Novel Areas for Prevention and Control of Canine Leishmaniosis.

PubMed

Miró, Guadalupe; Petersen, Christine; Cardoso, Luís; Bourdeau, Patrick; Baneth, Gad; Solano-Gallego, Laia; Pennisi, Maria Grazia; Ferrer, Lluís; Oliva, Gaetano

2017-09-01

There have been multiple recent advances regarding tools for the control and prevention of canine leishmaniosis (CanL), including new preventative vaccines. In this review, these advances are evaluated based on control targets, including vector and parasite. Leishvet recommendations are provided for control practices based on the dog's risk of infection. New topical insecticide formulations have proven to be effective in preventing sand fly bites, and subsequently infection. Parasite control occurs through chemotherapeutic or immunologic means, which decrease or prevent transmission to other animals, including humans. Leishmaniosis control programs that include a combination of coordinated measures, either in individuals or for prevention across reservoir populations, are required. Copyright © 2017 Elsevier Ltd. All rights reserved.

First survey of parasitic helminths of goats along the Han River in Hubei Province, China.

PubMed

Yang, Xin; Gasser, Robin B; Fang, Rui; Zeng, Jinrong; Zhu, Kaixiang; Qi, Mingwei; Zhang, Zongze; Tan, Li; Lei, Weiqiang; Zhou, Yanqin; Zhao, Junlong; Hu, Min

2016-09-01

Diseases caused by parasitic helminths cause considerable production and economic losses in livestock worldwide. Understanding the epidemiology of these parasites has important implications for controlling them. The main purpose of the present study was to estimate the prevalence of key parasitic helminths in goats along the Han River in Zhanggang, Hubei Province (from January to December 2014). We used faecal flotation and sedimentation techniques as well as PCR-based DNA sequencing to detect and identify helminths. Results showed that the prevalence of helminths was high throughout the year, particularly for gastrointestinal nematodes. These first findings provide useful baseline information for goat helminths in Zhanggang, and a starting point for the implementation of control programs. With an increased expansion of the goat industry in China, the findings also emphasise the need to undertake prevalence surveys in other regions of China where extensive farming practices are used.

A Survey Study on Gastrointestinal Parasites of Stray Cats in Northern Region of Nile Delta, Egypt

PubMed Central

Khalafalla, Reda E.

2011-01-01

A survey study on gastrointestinal parasites in 113 faecal samples from stray cats collected randomly from Kafrelsheikh province, northern region of Nile delta of Egypt; was conducted in the period between January and May 2010. The overall prevalence was 91%. The results of this study reported seven helminth species: Toxocara cati (9%), Ancylostoma tubaeforme (4%), Toxascaris leonina (5%), Dipylidium caninum (5%), Capillaria spp. (3%), Taenia taeniformis (22%) and Heterophyes heterophyes (3%), four protozoal species: Toxoplasma gondii (9%), Sarcocyst spp. (1%), Isospora spp. (2%) and Giardia spp. (2%) and two arthropod species; Linguatula serrata (2%) and mites eggs (13%). The overall prevalence of intestinal parasites may continue to rise due to lack of functional veterinary clinics for cat care in Egypt. Therefore, there is a need to plan adequate control programs to diagnose, treat and control gastrointestinal parasites of companion as well as stray cats in the region. PMID:21760884

Melatonin effects on Plasmodium life cycle: new avenues for therapeutic approach.

PubMed

Srinivasan, Venkataramanujam; Ahmad, Asma H; Mohamed, Mahaneem; Zakaria, Rahimah

2012-05-01

Malaria remains a global health problem affecting more than 515 million people all over the world including Malaysia. It is on the rise, even within unknown regions that previous to this were free of malaria. Although malaria eradication programs carried out by vector control programs are still effective, anti-malarial drugs are also used extensively for curtailing this disease. But resistance to the use of anti-malarial drugs is also increasing on a daily basis. With an increased understanding of mechanisms that cause growth, differentiation and development of malarial parasites in rodents and humans, new avenues of therapeutic approaches for controlling the growth, synchronization and development of malarial parasites are essential. Within this context, the recent discoveries related to IP3 interconnected signalling pathways, the release of Ca2+ from intracellular stores of Plasmodium, ubiquitin protease systems as a signalling pathway, and melatonin influencing the growth and differentiation of malarial parasites by its effects on these signalling pathways have opened new therapeutic avenues for arresting the growth and differentiation of malarial parasites. Indeed, the use of melatonin antagonist, luzindole, has inhibited the melatonin's effect on these signalling pathways and thereby has effectively reduced the growth and differentiation of malarial parasites. As Plasmodium has effective sensors which detect the nocturnal plasma melatonin concentrations, suppression of plasma melatonin levels with the use of bright light during the night or by anti-melatonergic drugs and by using anti-kinase drugs will help in eradicating malaria on a global level. A number of patients have been admitted with regards to the control and management of malarial growth. Patents related to the discovery of serpentine receptors on Plasmodium, essential for modulating intra parasitic melatonin levels, procedures for effective delivery of bright light to suppress plasma melatonin levels and thereby arresting the growth and elimination of malarial parasites from the blood of the host are all cited in the paper. The purpose of the paper is to highlight the importance of melatonin acting as a cue for Plasmodium faciparum growth and to discuss the ways of curbing the effects of melatonin on Plasmodium growth and for arresting its life cycle, as a method of eliminating the parasite from the host.

Geographic strain differentiation of Schistosoma japonicum in the Philippines using microsatellite markers

PubMed Central

Moendeg, Kharleezelle J.; Angeles, Jose Ma M.; Nakao, Ryo; Leonardo, Lydia R.; Fontanilla, Ian Kendrich C.; Goto, Yasuyuki; Kirinoki, Masashi; Villacorte, Elena A.; Rivera, Pilarita T.; Inoue, Noboru; Chigusa, Yuichi

2017-01-01

Background Microsatellites have been found to be useful in determining genetic diversities of various medically-important parasites which can be used as basis for an effective disease management and control program. In Asia and Africa, the identification of different geographical strains of Schistosoma japonicum, S. haematobium and S. mansoni as determined through microsatellites could pave the way for a better understanding of the transmission epidemiology of the parasite. Thus, the present study aims to apply microsatellite markers in analyzing the populations of S. japonicum from different endemic areas in the Philippines for possible strain differentiation. Methodology/ Principal findings Experimental mice were infected using the cercariae of S. japonicum collected from infected Oncomelania hupensis quadrasi snails in seven endemic municipalities. Adult worms were harvested from infected mice after 45 days of infection and their DNA analyzed against ten previously characterized microsatellite loci. High genetic diversity was observed in areas with high endemicity. The degree of genetic differentiation of the parasite population between endemic areas varies. Geographical separation was considered as one of the factors accounting for the observed difference between populations. Two subgroups have been observed in one of the study sites, suggesting that co-infection with several genotypes of the parasite might be present in the population. Clustering analysis showed no particular spatial structuring between parasite populations from different endemic areas. This result could possibly suggest varying degrees of effects of the ongoing control programs and the existing gene flow in the populations, which might be attributed to migration and active movement of infected hosts from one endemic area to another. Conclusions/ Significance Based on the results of the study, it is reasonable to conclude that genetic diversity could be one possible criterion to assess the infection status in highly endemic areas. Genetic surveillance using microsatellites is therefore important to predict the ongoing gene flow and degree of genetic diversity, which indirectly reflects the success of the control program in schistosomiasis-endemic areas. PMID:28692692

Fitness consequences of nest desertion in an endangered host, the least Bell's vireo

USGS Publications Warehouse

Kus, Barbara E.

2002-01-01

Recent analyses of the impact of cowbird parasitism on host productivity suggest that while parasitism reduces productivity on a per-nest basis, the ability of pairs to desert parasitized nests and renest allows them to achieve productivity comparable to that of unparasitized pairs. This has implications for the management of several endangered species that are highly vulnerable to parasitism and consequently the target of cowbird control programs. I calculated seasonal nesting effort (number of nests per pair) and productivity of 568 pairs of Least Bell's Vireos (Vireo bellii pusillus) monitored over 11 years at the San Luis Rey River in San Diego County, California (where cowbird trapping has reduced, but not eliminated, parasitism), assigning pairs to one of three groups: (1) deserters, (2) rescued (parasitized pairs with nests “rescued” from probable failure by the removal of cowbird eggs), and (3) unparasitized. Parasitized pairs attempted significantly more nests per season than did unparasitized pairs, with deserters producing more nests than rescued pairs. However, productivity of deserting pairs was significantly lower than that of both rescued and unparasitized pairs, largely because subsequent nests of deserting pairs were also parasitized. Seasonal productivity of rescued and unparasitized pairs was comparable, indicating that in this species, reduction of cowbird impacts through nest manipulation to remove cowbird eggs is effective. Desertion by Least Bell's Vireos does not appear to be an adequate natural defense against parasitism, suggesting the need for continued cowbird control while vireo populations are re-established.

Differential parasitism of seed-feeding Cydia (Lepidoptera: Tortricidae) by native and alien wasp species relative to elevation in subalpine Sophora (Fabaceae) forests on Mauna Kea, Hawaii

USGS Publications Warehouse

Oboyski, P.T.; Slotterback, J.W.; Banko, P.C.

2004-01-01

Alien parasitic wasps, including accidental introductions and purposefully released biological control agents, have been implicated in the decline of native Hawaiian Lepidoptera. Understanding the potential impacts of alien wasps requires knowledge of ecological parameters that influence parasitism rates for species in their new environment. Sophora seed-feeding Cydia spp. (Lepidoptera: Tortricidae) were surveyed for larval parasitoids to determine how native and alien wasps are partitioned over an elevation gradient (2200-2800 m) on Hawaii Island, Hawaii. Parasitism rate of native Euderus metallicus (Eulophidae) increased with increased elevation, while parasitism rate by immigrant Calliephialtes grapholithae (Ichneumonidae) decreased. Parasitism by Pristomerus hawaiiensis (Ichneumonidae), origins uncertain, also decreased with increased elevation. Two other species, Diadegma blackburni (Ichneumonidae), origins uncertain, and Brasema cushmani (Eupelmidae), a purposefully introduced biological control agent for pepper weevil, did not vary significantly with elevation. Results are contrasted with a previous study of this system with implications for the conservation of an endangered bird species that feed on Cydia larvae. Interpretation of results is hindered by lack of knowledge of autecology of moths and wasps, origins, phylogeny, systematics, competitive ability, and physiological limitations of each wasp species. These factors should be incorporated into risk analysis for biological control introductions and invasive species programs. ?? 2004 Kluwer Academic Publishers.

Prevalence of intestinal parasites among food handlers in Western Iran.

PubMed

Kheirandish, Farnaz; Tarahi, Mohammad Javad; Ezatpour, Behrouz

2014-01-01

Parasitic infection is one of the problems that affect human health, especially in developing countries. In this study, all of the fast food shops, restaurants, and roast meat outlets of Khorramabad (Western Iran) and all the staff employed by them, some 210 people, were selected through a census and their stools were examined for the presence of parasites. The parasitological tests of direct wet-mount, Lugol's iodine staining, formaldehyde-ether sedimentation and Trichrome staining techniques were performed on the samples. The data was analyzed with a chi-square test and logistic regression was selected as the analytical model. The results showed 19 (9%) stool specimens were positive for different intestinal parasites. These intestinal parasites included Giardia lamblia 2.9%, Entamoeba coli 4.3%, Blastocystis sp. 1.4%, and Hymenolepis nana 0.5%. There was a significant difference between the presence of a valid health card, awareness of transmission of intestinal parasites, participation in training courses in environmental health with intestinal parasites (p < 0.05). No statistically significant difference was found between the rate of literacy and gender among patients infected with intestinal parasites (p > 0.05). To control parasitic infection in food handlers, several strategies are recommended such as stool examinations every three months, public education, application of health regulations, controlling the validity of health cards and training on parasitic infection transmission. In this regard, the findings of the present study can be used as a basis to develop preventive programs targeting food handlers because the spread of disease via them is a common problem worldwide.

External quality assurance of malaria nucleic acid testing for clinical trials and eradication surveillance.

PubMed

Murphy, Sean C; Hermsen, Cornelus C; Douglas, Alexander D; Edwards, Nick J; Petersen, Ines; Fahle, Gary A; Adams, Matthew; Berry, Andrea A; Billman, Zachary P; Gilbert, Sarah C; Laurens, Matthew B; Leroy, Odile; Lyke, Kristen E; Plowe, Christopher V; Seilie, Annette M; Strauss, Kathleen A; Teelen, Karina; Hill, Adrian V S; Sauerwein, Robert W

2014-01-01

Nucleic acid testing (NAT) for malaria parasites is an increasingly recommended diagnostic endpoint in clinical trials of vaccine and drug candidates and is also important in surveillance of malaria control and elimination efforts. A variety of reported NAT assays have been described, yet no formal external quality assurance (EQA) program provides validation for the assays in use. Here, we report results of an EQA exercise for malaria NAT assays. Among five centers conducting controlled human malaria infection trials, all centers achieved 100% specificity and demonstrated limits of detection consistent with each laboratory's pre-stated expectations. Quantitative bias of reported results compared to expected results was generally <0.5 log10 parasites/mL except for one laboratory where the EQA effort identified likely reasons for a general quantitative shift. The within-laboratory variation for all assays was low at <10% coefficient of variation across a range of parasite densities. Based on this study, we propose to create a Molecular Malaria Quality Assessment program that fulfills the need for EQA of malaria NAT assays worldwide.

The complexities of malaria disease manifestations with a focus on asymptomatic malaria

PubMed Central

2012-01-01

Malaria is a serious parasitic disease in the developing world, causing high morbidity and mortality. The pathogenesis of malaria is complex, and the clinical presentation of disease ranges from severe and complicated, to mild and uncomplicated, to asymptomatic malaria. Despite a wealth of studies on the clinical severity of disease, asymptomatic malaria infections are still poorly understood. Asymptomatic malaria remains a challenge for malaria control programs as it significantly influences transmission dynamics. A thorough understanding of the interaction between hosts and parasites in the development of different clinical outcomes is required. In this review, the problems and obstacles to the study and control of asymptomatic malaria are discussed. The human and parasite factors associated with differential clinical outcomes are described and the management and treatment strategies for the control of the disease are outlined. Further, the crucial gaps in the knowledge of asymptomatic malaria that should be the focus of future research towards development of more effective malaria control strategies are highlighted. PMID:22289302

Battling Wormy apples in the Home Orchard Using a SOFT Approach

USDA-ARS?s Scientific Manuscript database

A program was developed for use by homeowners to control codling moth in backyard apple and pear trees. Coined SOFT (Selective Organic Fruit Tree), this management program uses a combination of granulosis virus, parasitic nematodes, and a trap and lure for females. This multi-tactic approach reduced...

Tissue parasitic helminthiases are prevalent at Cheongjin, North Korea

PubMed Central

Shen, Chenghua; Li, Shunyu; Zheng, Shanzi; Choi, Min-Ho; Bae, Young Mee

2007-01-01

We investigated a small-scale serological survey to screen tissue-parasitic helminthiases of North Koreans as one of research programs for re-unification of Korea. Soil-transmitted helminthiases were found highly prevalent among North Korean residents at the border with China. ELISA using 4 tissue-parasitic helminth antigens was applied to 137 residents living in Cheongjin-shi, Hamgyeongbuk-do, North Korea and 133 female refugees in South Korea in 2004-2005. Among a total of 270 samples, 31 (11.5%), 25 (9.3%), and 11 (4.1%) were positive for specific IgG antibodies to antigens of Clonorchis sinensis, Taenia solium metacestode, and sparganum, respectively. The overall positive rate was 21.5%; 38.2% in males and 15.8% in females. The present finding suggests that tissue parasites, such as C. sinensis, T. solium metacestode and sparganum are highly prevalent in some limited areas of North Korea. These foodborne tissue-parasitic helminthiases should be considered for future control measures of parasitic diseases in North Korea. PMID:17570978

Tissue parasitic helminthiases are prevalent at Cheongjin, North Korea.

PubMed

Shen, Chenghua; Li, Shunyu; Zheng, Shanzi; Choi, Min Ho; Bae, Young Mee; Hong, Sung Tae

2007-06-01

We investigated a small-scale serological survey to screen tissue-parasitic helminthiases of North Koreans as one of research programs for re-unification of Korea. Soil-transmitted helminthiases were found highly prevalent among North Korean residents at the border with China. ELISA using 4 tissue-parasitic helminth antigens was applied to 137 residents living in Cheongjin-shi, Hamgyeongbuk-do, North Korea and 133 female refugees in South Korea in 2004-2005. Among a total of 270 samples, 31 (11.5%), 25 (9.3%), and 11 (4.1%) were positive for specific IgG antibodies to antigens of Clonorchis sinensis, Taenia solium metacestode, and sparganum, respectively. The overall positive rate was 21.5%; 38.2% in males and 15.8% in females. The present finding suggests that tissue parasites, such as C. sinensis, T. solium metacestode and sparganum are highly prevalent in some limited areas of North Korea. These foodborne tissue-parasitic helminthiases should be considered for future control measures of parasitic diseases in North Korea.

Soil-transmitted helminthiases: implications of climate change and human behavior.

PubMed

Weaver, Haylee J; Hawdon, John M; Hoberg, Eric P

2010-12-01

Soil-transmitted helminthiases (STHs) collectively cause the highest global burden of parasitic disease after malaria and are most prevalent in the poorest communities, especially in sub-Saharan Africa. Climate change is predicted to alter the physical environment through cumulative impacts of warming and extreme fluctuations in temperature and precipitation, with cascading effects on human health and wellbeing, food security and socioeconomic infrastructure. Understanding how the spectrum of climate change effects will influence STHs is therefore of critical importance to the control of the global burden of human parasitic disease. Realistic progress in the global control of STH in a changing climate requires a multidisciplinary approach that includes the sciences (e.g. thermal thresholds for parasite development and resilience) and social sciences (e.g. behavior and implementation of education and sanitation programs). Copyright © 2010 Elsevier Ltd. All rights reserved.

Major Threat to Malaria Control Programs by Plasmodium falciparum Lacking Histidine-Rich Protein 2, Eritrea

PubMed Central

Berhane, Araia; Anderson, Karen; Mihreteab, Selam; Gresty, Karryn; Rogier, Eric; Mohamed, Salih; Hagos, Filmon; Embaye, Ghirmay; Chinorumba, Anderson; Zehaie, Assefash; Dowd, Simone; Waters, Norman C.; Gatton, Michelle L.; Udhayakumar, Venkatachalam; Cunningham, Jane

2018-01-01

False-negative results for Plasmodium falciparum histidine-rich protein (HRP) 2–based rapid diagnostic tests (RDTs) are increasing in Eritrea. We investigated HRP gene 2/3 (pfhrp2/pfhrp3) status in 50 infected patients at 2 hospitals. We showed that 80.8% (21/26) of patients at Ghindae Hospital and 41.7% (10/24) at Massawa Hospital were infected with pfhrp2-negative parasites and 92.3% (24/26) of patients at Ghindae Hospital and 70.8% (17/24) at Massawa Hospital were infected with pfhrp3-negative parasites. Parasite densities between pfhrp2-positive and pfhrp2-negative patients were comparable. All pfhrp2-negative samples had no detectable HRP2/3 antigen and showed negative results for HRP2-based RDTs. pfhrp2-negative parasites were genetically less diverse and formed 2 clusters with no close relationships to parasites from Peru. These parasites probably emerged independently by selection in Eritrea. High prevalence of pfhrp2-negative parasites caused a high rate of false-negative results for RDTs. Determining prevalence of pfhrp2-negative parasites is urgently needed in neighboring countries to assist case management policies. PMID:29460730

Major Threat to Malaria Control Programs by Plasmodium falciparum Lacking Histidine-Rich Protein 2, Eritrea.

PubMed

Berhane, Araia; Anderson, Karen; Mihreteab, Selam; Gresty, Karryn; Rogier, Eric; Mohamed, Salih; Hagos, Filmon; Embaye, Ghirmay; Chinorumba, Anderson; Zehaie, Assefash; Dowd, Simone; Waters, Norman C; Gatton, Michelle L; Udhayakumar, Venkatachalam; Cheng, Qin; Cunningham, Jane

2018-03-01

False-negative results for Plasmodium falciparum histidine-rich protein (HRP) 2-based rapid diagnostic tests (RDTs) are increasing in Eritrea. We investigated HRP gene 2/3 (pfhrp2/pfhrp3) status in 50 infected patients at 2 hospitals. We showed that 80.8% (21/26) of patients at Ghindae Hospital and 41.7% (10/24) at Massawa Hospital were infected with pfhrp2-negative parasites and 92.3% (24/26) of patients at Ghindae Hospital and 70.8% (17/24) at Massawa Hospital were infected with pfhrp3-negative parasites. Parasite densities between pfhrp2-positive and pfhrp2-negative patients were comparable. All pfhrp2-negative samples had no detectable HRP2/3 antigen and showed negative results for HRP2-based RDTs. pfhrp2-negative parasites were genetically less diverse and formed 2 clusters with no close relationships to parasites from Peru. These parasites probably emerged independently by selection in Eritrea. High prevalence of pfhrp2-negative parasites caused a high rate of false-negative results for RDTs. Determining prevalence of pfhrp2-negative parasites is urgently needed in neighboring countries to assist case management policies.

An automatic device for detection and classification of malaria parasite species in thick blood film.

PubMed

Kaewkamnerd, Saowaluck; Uthaipibull, Chairat; Intarapanich, Apichart; Pannarut, Montri; Chaotheing, Sastra; Tongsima, Sissades

2012-01-01

Current malaria diagnosis relies primarily on microscopic examination of Giemsa-stained thick and thin blood films. This method requires vigorously trained technicians to efficiently detect and classify the malaria parasite species such as Plasmodium falciparum (Pf) and Plasmodium vivax (Pv) for an appropriate drug administration. However, accurate classification of parasite species is difficult to achieve because of inherent technical limitations and human inconsistency. To improve performance of malaria parasite classification, many researchers have proposed automated malaria detection devices using digital image analysis. These image processing tools, however, focus on detection of parasites on thin blood films, which may not detect the existence of parasites due to the parasite scarcity on the thin blood film. The problem is aggravated with low parasitemia condition. Automated detection and classification of parasites on thick blood films, which contain more numbers of parasite per detection area, would address the previous limitation. The prototype of an automatic malaria parasite identification system is equipped with mountable motorized units for controlling the movements of objective lens and microscope stage. This unit was tested for its precision to move objective lens (vertical movement, z-axis) and microscope stage (in x- and y-horizontal movements). The average precision of x-, y- and z-axes movements were 71.481 ± 7.266 μm, 40.009 ± 0.000 μm, and 7.540 ± 0.889 nm, respectively. Classification of parasites on 60 Giemsa-stained thick blood films (40 blood films containing infected red blood cells and 20 control blood films of normal red blood cells) was tested using the image analysis module. By comparing our results with the ones verified by trained malaria microscopists, the prototype detected parasite-positive and parasite-negative blood films at the rate of 95% and 68.5% accuracy, respectively. For classification performance, the thick blood films with Pv parasite was correctly classified with the success rate of 75% while the accuracy of Pf classification was 90%. This work presents an automatic device for both detection and classification of malaria parasite species on thick blood film. The system is based on digital image analysis and featured with motorized stage units, designed to easily be mounted on most conventional light microscopes used in the endemic areas. The constructed motorized module could control the movements of objective lens and microscope stage at high precision for effective acquisition of quality images for analysis. The analysis program could accurately classify parasite species, into Pf or Pv, based on distribution of chromatin size.

Nutritional status in parasitized and nonparasitized children from two districts of Buenos Aires, Argentina.

PubMed

Orden, Alicia B; Apezteguía, María C; Ciarmela, María L; Molina, Nora B; Pezzani, Betina C; Rosa, Diana; Minvielle, Marta C

2014-01-01

The Program for the Control of Intestinal Parasites and Nutrition was designed to intervene in small communities to prevent and control the effects of parasitic infections on children's health. To analyze the association between nutritional status and parasitic infection in suburban and rural children from Buenos Aires, Argentina. Nutritional status was assessed by anthropometric (weight, height, BMI, skinfolds, upper arm circumference, muscle, and fat upper arm areas) and biochemical (Hb, Ca, Mg, Zn, and Cu) indicators. Parasitological analysis were made on both serial stool and perianal swab samples. A total of 708 children aged 3-11 were measured. The biochemical analysis included 217 blood samples and the parasitological study included 284 samples. Anthropometric status was similar in both settings with low rates of underweight and stunting (<6%), and high rates of overweight (~17%) and obesity (~12%). Ca deficiency was significantly higher in suburban children where 80% of them were hypocalcemic. Around 70% of fecal samples contained parasites. Among infected children, the most prevalent species were Blastocystis hominis and Enterobius vermicularis (~43%) followed by Giardia lamblia (~17%). Differences in parasitological status between districts were not significant. In the suburban district parasitized children were lighter, shorter, and had a lower upper arm circumference than their non-infected peers. No differences in anthropometric status were seen among infected and uninfected rural children. The results suggest an association between intestinal parasites and physical growth in suburban children. Rural children seem to be protected against the effects of parasitic infection. Copyright © 2013 Wiley Periodicals, Inc.

Generation of quinolone antimalarials targeting the Plasmodium falciparum mitochondrial respiratory chain for the treatment and prophylaxis of malaria

PubMed Central

Biagini, Giancarlo A.; Fisher, Nicholas; Shone, Alison E.; Mubaraki, Murad A.; Srivastava, Abhishek; Hill, Alisdair; Antoine, Thomas; Warman, Ashley J.; Davies, Jill; Pidathala, Chandrakala; Amewu, Richard K.; Leung, Suet C.; Sharma, Raman; Gibbons, Peter; Hong, David W.; Pacorel, Bénédicte; Lawrenson, Alexandre S.; Charoensutthivarakul, Sitthivut; Taylor, Lee; Berger, Olivier; Mbekeani, Alison; Stocks, Paul A.; Nixon, Gemma L.; Chadwick, James; Hemingway, Janet; Delves, Michael J.; Sinden, Robert E.; Zeeman, Anne-Marie; Kocken, Clemens H. M.; Berry, Neil G.; O’Neill, Paul M.; Ward, Stephen A.

2012-01-01

There is an urgent need for new antimalarial drugs with novel mechanisms of action to deliver effective control and eradication programs. Parasite resistance to all existing antimalarial classes, including the artemisinins, has been reported during their clinical use. A failure to generate new antimalarials with novel mechanisms of action that circumvent the current resistance challenges will contribute to a resurgence in the disease which would represent a global health emergency. Here we present a unique generation of quinolone lead antimalarials with a dual mechanism of action against two respiratory enzymes, NADH:ubiquinone oxidoreductase (Plasmodium falciparum NDH2) and cytochrome bc1. Inhibitor specificity for the two enzymes can be controlled subtly by manipulation of the privileged quinolone core at the 2 or 3 position. Inhibitors display potent (nanomolar) activity against both parasite enzymes and against multidrug-resistant P. falciparum parasites as evidenced by rapid and selective depolarization of the parasite mitochondrial membrane potential, leading to a disruption of pyrimidine metabolism and parasite death. Several analogs also display activity against liver-stage parasites (Plasmodium cynomolgi) as well as transmission-blocking properties. Lead optimized molecules also display potent oral antimalarial activity in the Plasmodium berghei mouse malaria model associated with favorable pharmacokinetic features that are aligned with a single-dose treatment. The ease and low cost of synthesis of these inhibitors fulfill the target product profile for the generation of a potent, safe, and inexpensive drug with the potential for eventual clinical deployment in the control and eradication of falciparum malaria. PMID:22566611

Schistosomiasis Sustained Control Program in Ethnic Groups Around Ninefescha (Eastern Senegal).

PubMed

N'Diaye, Monique; Dioukhane, Elhadji M; Ndao, Babacar; Diedhiou, Kemo; Diawara, Lamine; Talla, Idrissa; Vernet, Charlotte; Bessin, François; Barbier, Dominique; Dewavrin, Patrick; Klotz, Francis; Georges, Pierre

2016-09-07

Schistosomiasis is the second most significant parasitic disease in children in several African countries. For this purpose, the "Programme National de Lutte contre les Bilharzioses" (PNLB) was developed in partnership with the World Health Organization (WHO) to control this disease in Senegal. However, geographic isolation of Bedik ethnic groups challenged implementation of the key elements of the schistosomiasis program in eastern Senegal, and therefore, a hospital was established in Ninefescha to improve access to health care as well as laboratory support for this population. The program we have implemented from 2008 in partnership with the PNLB/WHO involved campaigns to 1) evaluate schistosomiasis prevalence in children of 53 villages around Ninefescha hospital, 2) perform a mass drug administration following the protocol established by the PNLB in school-aged children, 3) monitor annual prevalence, 4) implement health education campaigns, and 5) oversee the building of latrines. This campaign led to a drop in schistosomiasis prevalence but highlighted that sustainable schistosomiasis control by praziquantel treatment, awareness of the use of latrines, and inhabitants' voluntary commitment to the program are crucial to improve Schistosoma elimination. Moreover, this study revealed that preschool-aged children, for whom praziquantel was not recommended until 2014 in Senegal, constituted a significant reservoir for the parasite. © The American Society of Tropical Medicine and Hygiene.

Malaria in South Asia: Prevalence and control

PubMed Central

Kumar, Ashwani; Chery, Laura; Biswas, Chinmoy; Dubhashi, Nagesh; Dutta, Prafulla; Dua, Virendra Kumar; Kacchap, Mridula; Kakati, Sanjeeb; Khandeparkar, Anar; Kour, Dalip; Mahajanj, Satish N.; Maji, Ardhendu; Majumder, Partha; Mohanta, Jagadish; Mohapatra, Pradyumna K.; Narayanasamy, Krishnamoorthy; Roy, Krishnangshu; Shastri, Jayanthi; Valecha, Neena; Vikash, Rana; Wani, Reena; White, John; Rathod, Pradipsinh K

2013-01-01

The “Malaria Evolution in South Asia” (MESA) program project is an International Center of Excellence for Malaria Research (ICEMR) sponsored by the US National Institutes of Health. This US–India collaborative program will study the origin of genetic diversity of malaria parasites and their selection on the Indian subcontinent. This knowledge should contribute to a better understanding of unexpected disease outbreaks and unpredictable disease presentations from Plasmodium falciparum and Plasmodium vivax infections. In this first of two reviews, we highlight malaria prevalence in India. In particular, we draw attention to variations in distribution of different human-parasites and different vectors, variation in drug resistance traits, and multiple forms of clinical presentations. Uneven malaria severity in India is often attributed to large discrepancies in health care accessibility as well as human migrations within the country and across neighboring borders. Poor access to health care goes hand in hand with poor reporting from some of the same areas, combining to possibly distort disease prevalence and death from malaria in some parts of India. Corrections are underway in the form of increased resources for disease control, greater engagement of village-level health workers for early diagnosis and treatment, and possibly new public–private partnerships activities accompanying traditional national malaria control programs in the most severely affected areas. A second accompanying review raises the possibility that, beyond uneven health care, evolutionary pressures may alter malaria parasites in ways that contribute to severe disease in India, particularly in the NE corridor of India bordering Myanmar Narayanasamy et al., 2012. PMID:22248528

Malaria in South Asia: prevalence and control.

PubMed

Kumar, Ashwani; Chery, Laura; Biswas, Chinmoy; Dubhashi, Nagesh; Dutta, Prafulla; Dua, Virendra Kumar; Kacchap, Mridula; Kakati, Sanjeeb; Khandeparkar, Anar; Kour, Dalip; Mahajan, Satish N; Maji, Ardhendu; Majumder, Partha; Mohanta, Jagadish; Mohapatra, Pradyumna K; Narayanasamy, Krishnamoorthy; Roy, Krishnangshu; Shastri, Jayanthi; Valecha, Neena; Vikash, Rana; Wani, Reena; White, John; Rathod, Pradipsinh K

2012-03-01

The "Malaria Evolution in South Asia" (MESA) program project is an International Center of Excellence for Malaria Research (ICEMR) sponsored by the US National Institutes of Health. This US-India collaborative program will study the origin of genetic diversity of malaria parasites and their selection on the Indian subcontinent. This knowledge should contribute to a better understanding of unexpected disease outbreaks and unpredictable disease presentations from Plasmodium falciparum and Plasmodium vivax infections. In this first of two reviews, we highlight malaria prevalence in India. In particular, we draw attention to variations in distribution of different human-parasites and different vectors, variation in drug resistance traits, and multiple forms of clinical presentations. Uneven malaria severity in India is often attributed to large discrepancies in health care accessibility as well as human migrations within the country and across neighboring borders. Poor access to health care goes hand in hand with poor reporting from some of the same areas, combining to possibly distort disease prevalence and death from malaria in some parts of India. Corrections are underway in the form of increased resources for disease control, greater engagement of village-level health workers for early diagnosis and treatment, and possibly new public-private partnerships activities accompanying traditional national malaria control programs in the most severely affected areas. A second accompanying review raises the possibility that, beyond uneven health care, evolutionary pressures may alter malaria parasites in ways that contribute to severe disease in India, particularly in the NE corridor of India bordering Myanmar Narayanasamy et al., 2012. Copyright © 2012 Elsevier B.V. All rights reserved.

JWST ISIM Harness Thermal Evaluation

NASA Technical Reports Server (NTRS)

Kobel, Mark; Glazer, Stuart; Tuttle, Jim; Martins, Mario; Ruppel, Sean

2008-01-01

The James Webb Space Telescope (JWST) will be a large infrared telescope with a 6.5-meter primary mirror. Launch is planned for 2013. JWST wl1 be the premier observatory of the next decade serving thousands of astronomers worldwide. The Integrated Science Instrument Module (ISIM) is the unit that will house thc four main JWST instruments. The ISIM enclosure passively cooled to 37 Kelvin and has a tightly managed thermal budget. A significant portion of the ISIM heat load is due to parasitic heat gains from the instrument harnesses. These harnesses provide a thermal path from the Instrument Electronics Control (IEC) to the ISIM. Because of the impact of this load to the ISIM thermal design, understanding the harness parasitic heat gains is critical. To this effect, a thermal test program has been conducted in order to characterize these parasitic loads and verify harness thermal models. Recent parasitic heat loads tests resulted in the addition of a dedicated multiple stage harness radiator. In order for the radiator to efficiently reject heat from the harness, effective thermal contact conductance values for multiple harnesses had to be determined. This presentation will describe the details and the results of this test program.

A PCR-based survey of selected Babesia and Theileria parasites in cattle in Sri Lanka.

PubMed

Sivakumar, Thillaiampalam; Kothalawala, Hemal; Abeyratne, Sembukutti Arachchige Eranga; Vimalakumar, Singarayar Caniciyas; Meewewa, Asela Sanjeewa; Hadirampela, Dilhani Thilanka; Puvirajan, Thamotharampillai; Sukumar, Subramaniyam; Kuleswarakumar, Kulanayagam; Chandrasiri, Alawattage Don Nimal; Igarashi, Ikuo; Yokoyama, Naoaki

2012-11-23

Hemoprotozoan parasites are responsible for significant economic losses in cattle. We screened Sri Lankan cattle populations for the presence of Babesia bovis, Babesia bigemina, Theileria annulata, and Theileria orientalis, using species-specific PCR assays. Out of 316 samples collected from animals in four different districts of Sri Lanka (Nuwara Eliya, Polonnaruwa, Ampara, and Jaffna), 231 (73.1%) were positive for at least one parasite species. All four parasite species were detected among the study groups from all of the districts surveyed. The first and second commonest hemoprotozoan parasites identified were T. orientalis (53.5%) and B. bigemina (30.1%), respectively. We found that the dry zones (Polonnaruwa, Ampara, and Jaffna) had more Babesia-positive animals than the hill country wet zone (Nuwara Eliya). In contrast, T. orientalis was the predominant species detected in Nuwara Eliya, while infection with T. annulata was more common in the dry zones. In addition, 81 (35.1%) of the 231 positive samples were infected with more than one parasite species. The presence of multiple parasite species among the different cattle populations is of clinical and economic significance. Therefore, island-wide control and prevention programs against bovine babesiosis and theileriosis are needed to minimize the financial burden caused by these parasites. Copyright © 2012 Elsevier B.V. All rights reserved.

Molecular diagnosis of malaria by photo-induced electron transfer fluorogenic primers: PET-PCR.

PubMed

Lucchi, Naomi W; Narayanan, Jothikumar; Karell, Mara A; Xayavong, Maniphet; Kariuki, Simon; DaSilva, Alexandre J; Hill, Vincent; Udhayakumar, Venkatachalam

2013-01-01

There is a critical need for developing new malaria diagnostic tools that are sensitive, cost effective and capable of performing large scale diagnosis. The real-time PCR methods are particularly robust for large scale screening and they can be used in malaria control and elimination programs. We have designed novel self-quenching photo-induced electron transfer (PET) fluorogenic primers for the detection of P. falciparum and the Plasmodium genus by real-time PCR. A total of 119 samples consisting of different malaria species and mixed infections were used to test the utility of the novel PET-PCR primers in the diagnosis of clinical samples. The sensitivity and specificity were calculated using a nested PCR as the gold standard and the novel primer sets demonstrated 100% sensitivity and specificity. The limits of detection for P. falciparum was shown to be 3.2 parasites/µl using both Plasmodium genus and P. falciparum-specific primers and 5.8 parasites/µl for P. ovale, 3.5 parasites/µl for P. malariae and 5 parasites/µl for P. vivax using the genus specific primer set. Moreover, the reaction can be duplexed to detect both Plasmodium spp. and P. falciparum in a single reaction. The PET-PCR assay does not require internal probes or intercalating dyes which makes it convenient to use and less expensive than other real-time PCR diagnostic formats. Further validation of this technique in the field will help to assess its utility for large scale screening in malaria control and elimination programs.

Broomrape Weeds. Underground Mechanisms of Parasitism and Associated Strategies for their Control: A Review

PubMed Central

Fernández-Aparicio, Mónica; Reboud, Xavier; Gibot-Leclerc, Stephanie

2016-01-01

Broomrapes are plant-parasitic weeds which constitute one of the most difficult-to-control of all biotic constraints that affect crops in Mediterranean, central and eastern Europe, and Asia. Due to their physical and metabolic overlap with the crop, their underground parasitism, their achlorophyllous nature, and hardly destructible seed bank, broomrape weeds are usually not controlled by management strategies designed for non-parasitic weeds. Instead, broomrapes are in current state of intensification and spread due to lack of broomrape-specific control programs, unconscious introduction to new areas and may be decline of herbicide use and global warming to a lesser degree. We reviewed relevant facts about the biology and physiology of broomrape weeds and the major feasible control strategies. The points of vulnerability of some underground events, key for their parasitism such as crop-induced germination or haustorial development are reviewed as inhibition targets of the broomrape-crop association. Among the reviewed strategies are those aimed (1) to reduce broomrape seed bank viability, such as fumigation, herbigation, solarization and use of broomrape-specific pathogens; (2) diversion strategies to reduce the broomrape ability to timely detect the host such as those based on promotion of suicidal germination, on introduction of allelochemical interference, or on down-regulating host exudation of germination-inducing factors; (3) strategies to inhibit the capacity of the broomrape seedling to penetrate the crop and connect with the vascular system, such as biotic or abiotic inhibition of broomrape radicle growth and crop resistance to broomrape penetration either natural, genetically engineered or elicited by biotic- or abiotic-resistance-inducing agents; and (4) strategies acting once broomrape seedling has bridged its vascular system with that of the host, aimed to impede or to endure the parasitic sink such as those based on the delivery of herbicides via haustoria, use of resistant or tolerant varieties and implementation of cultural practices improving crop competitiveness. PMID:26925071

Gastrointestinal parasites of canids, a latent risk to human health in Tunisia.

PubMed

Oudni-M'rad, Myriam; Chaâbane-Banaoues, Raja; M'rad, Selim; Trifa, Fatma; Mezhoud, Habib; Babba, Hamouda

2017-06-05

Although data on the parasite environmental contamination are crucial to implement strategies for control and treatment, information about zoonotic helminths is very limited in Tunisia. Contamination of areas with canid faeces harboring infective parasite elements represents a relevant health-risk impact for humans. The aim of this study was to assess the environmental contamination with eggs and oocysts of gastrointestinal parasites of dogs and wild canids in Tunisia with special attention to those that can be transmitted to humans. One thousand two hundred and seventy faecal samples from stray dogs and 104 from wild canids (red foxes and golden jackals) were collected from different geographical regions throughout Tunisia. The helminth eggs and protozoan oocysts were concentrated by sucrose flotation and identified by microscopic examination. The most frequently observed parasites in dog samples were Toxocara spp. (27.2%), E. granulosus (25.8%), and Coccidia (13.1%). For wild canid faeces, the most commonly encountered parasites were Toxocara spp. (16.3%) followed by Capillaria spp. (9.6%). The parasite contamination of dog faeces varied significantly from one region to another in function of the climate. To our knowledge, the study highlights for the first time in Tunisia a serious environmental contamination by numerous parasitic stages infective to humans. Efforts should be made to increase the awareness of the contamination risk of such parasites in the environment and implement a targeted educational program.

Quantifying the impact of human mobility on malaria

PubMed Central

Wesolowski, Amy; Eagle, Nathan; Tatem, Andrew J.; Smith, David L.; Noor, Abdisalan M.; Snow, Robert W.; Buckee, Caroline O.

2013-01-01

Human movements contribute to the transmission of malaria on spatial scales that exceed the limits of mosquito dispersal. Identifying the sources and sinks of imported infections due to human travel and locating high-risk sites of parasite importation could greatly improve malaria control programs. Here we use spatially explicit mobile phone data and malaria prevalence information from Kenya to identify the dynamics of human carriers that drive parasite importation between regions. Our analysis identifies specific importation routes that contribute to malaria epidemiology on regional spatial scales. PMID:23066082

How molecular epidemiology studies can support the National Malaria Control Program in Papua New Guinea.

PubMed

Koepfli, Cristian; Barry, Alyssa; Javati, Sarah; Timinao, Lincoln; Nate, Elma; Mueller, Ivo; Barnadas, Celine

2014-01-01

Papua New Guinea (PNG) is undertaking intensified efforts to control malaria. The National Malaria Control Program aims to reduce the burden of disease by large-scale distribution of insecticide-treated bednets, improved diagnosis and implementation of new treatments. A scientific program monitoring the effect of these interventions, including molecular epidemiology studies, closely accompanies the program. Laboratory assays have been developed in (or transferred to) PNG to measure prevalence of infection and intensity of transmission as well as potential resistance to currently used drugs. These assays help to assess the impact of the National Malaria Control Program, and they reveal a much clearer picture of malaria epidemiology in PNG. In addition, analysis of the geographical clustering of parasites aids in selecting areas where intensified control will be most successful. This paper gives an overview of current research and recently completed studies in the molecular epidemiology of malaria conducted in Papua New Guinea.

The interrelation between intestinal parasites and latent TB infections among newly resettled refugees in Texas.

PubMed

Board, Amy R; Suzuki, Sumihiro

2016-01-01

Previous research has documented that parasite infection may increase vulnerability to TB among certain at risk populations. The purpose of this study was to identify whether an association exists between latent tuberculosis infection (LTBI) and intestinal parasite infection among newly resettled refugees in Texas while controlling for additional effects of region of origin, age and sex. Data for all refugees screened for both TB and intestinal parasites between January 2010 and mid-October 2013 were obtained from the Texas Refugee Health Screening Program and were analyzed using logistic regression. A total of 9860 refugees were included. In multivariable logistic regression analysis, pathogenic and non-pathogenic intestinal parasite infections yielded statistically significant reduced odds of LTBI. However, when individual parasite species were analyzed, hookworm infection indicated statistically significant increased odds of LTBI (OR 1.674, CI: 1.126-2.488). A positive association exists between hookworm infection and LTBI in newly arrived refugees to Texas. More research is needed to assess the nature and extent of these associations. © The Author 2015. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Trypanosoma cruzi: adaptation to its vectors and its hosts

PubMed Central

Noireau, François; Diosque, Patricio; Jansen, Ana Maria

2009-01-01

American trypanosomiasis is a parasitic zoonosis that occurs throughout Latin America. The etiological agent, Trypanosoma cruzi, is able to infect almost all tissues of its mammalian hosts and spreads in the environment in multifarious transmission cycles that may or not be connected. This biological plasticity, which is probably the result of the considerable heterogeneity of the taxon, exemplifies a successful adaptation of a parasite resulting in distinct outcomes of infection and a complex epidemiological pattern. In the 1990s, most endemic countries strengthened national control programs to interrupt the transmission of this parasite to humans. However, many obstacles remain to the effective control of the disease. Current knowledge of the different components involved in elaborate system that is American trypanosomiasis (the protozoan parasite T. cruzi, vectors Triatominae and the many reservoirs of infection), as well as the interactions existing within the system, is still incomplete. The Triatominae probably evolve from predatory reduvids in response to the availability of vertebrate food source. However, the basic mechanisms of adaptation of some of them to artificial ecotopes remain poorly understood. Nevertheless, these adaptations seem to be associated with a behavioral plasticity, a reduction in the genetic repertoire and increasing developmental instability. PMID:19250627

Sublethal effects of insecticides used in soybean on the parasitoid Trichogramma pretiosum.

PubMed

de Paiva, Ana Clara Ribeiro; Beloti, Vitor Hugo; Yamamoto, Pedro Takao

2018-05-01

To control crop pests, parasitoid wasps of the genus Trichogramma are one alternative to the use of insecticides. Since a wide variety of agrochemicals may be applied to the same crops, it is essential to assess the selectivity of insecticides used for pest control on Trichogramma pretiosum. Information on which insecticides are less harmful to T. pretiosum can improve biological control using this insect, an important tactic in IPM programs for field crops. This study aimed to determine the effects of insecticides on the pupal stage and on the parasitism capacity of T. pretiosum. Lambda-cyhalothrin + thiamethoxam were slightly harmful and chlorpyriphos was moderately harmful to the pupal stage, while acephate, chlorfenapyr and flubendiamide, although considered innocuous, affected the succeeding generations of wasps, with low emergence of F 1 . Chlorfenapyr, chlorpyriphos and lambda-cyhalothrin + thiamethoxam reduced the parasitism, and acephate had a deleterious effect on the generation that contacted the insecticide residue. For an effective IPM program, it is important to apply selective insecticides. Further studies are needed to determine the selectivity of these insecticides under field conditions.

Exploring the Gastrointestinal "Nemabiome": Deep Amplicon Sequencing to Quantify the Species Composition of Parasitic Nematode Communities.

PubMed

Avramenko, Russell W; Redman, Elizabeth M; Lewis, Roy; Yazwinski, Thomas A; Wasmuth, James D; Gilleard, John S

2015-01-01

Parasitic helminth infections have a considerable impact on global human health as well as animal welfare and production. Although co-infection with multiple parasite species within a host is common, there is a dearth of tools with which to study the composition of these complex parasite communities. Helminth species vary in their pathogenicity, epidemiology and drug sensitivity and the interactions that occur between co-infecting species and their hosts are poorly understood. We describe the first application of deep amplicon sequencing to study parasitic nematode communities as well as introduce the concept of the gastro-intestinal "nemabiome". The approach is analogous to 16S rDNA deep sequencing used to explore microbial communities, but utilizes the nematode ITS-2 rDNA locus instead. Gastro-intestinal parasites of cattle were used to develop the concept, as this host has many well-defined gastro-intestinal nematode species that commonly occur as complex co-infections. Further, the availability of pure mono-parasite populations from experimentally infected cattle allowed us to prepare mock parasite communities to determine, and correct for, species representation biases in the sequence data. We demonstrate that, once these biases have been corrected, accurate relative quantitation of gastro-intestinal parasitic nematode communities in cattle fecal samples can be achieved. We have validated the accuracy of the method applied to field-samples by comparing the results of detailed morphological examination of L3 larvae populations with those of the sequencing assay. The results illustrate the insights that can be gained into the species composition of parasite communities, using grazing cattle in the mid-west USA as an example. However, both the technical approach and the concept of the 'nemabiome' have a wide range of potential applications in human and veterinary medicine. These include investigations of host-parasite and parasite-parasite interactions during co-infection, parasite epidemiology, parasite ecology and the response of parasite populations to both drug treatments and control programs.

Major trends in human parasitic diseases in China.

PubMed

Li, Ting; He, Shenyi; Zhao, Hong; Zhao, Guanghui; Zhu, Xing-Quan

2010-05-01

Tremendous progress has been made in the control and prevention of human parasitic diseases in mainland China in the past 30 years because of China's Reform and Opening to the Outside Policies initiated in 1978. However, parasitic diseases remain a major human health problem, with significant morbidity and mortality as well as adverse socioeconomic consequences. Although soil-transmitted parasitic diseases are in the process of being gradually controlled, food-borne parasitic diseases and emerging parasitic diseases are becoming the focus of new campaigns for control and prevention. This article reviews major trends in human parasitic diseases in mainland China, with perspectives for control.

Molecular Diagnosis of Malaria by Photo-Induced Electron Transfer Fluorogenic Primers: PET-PCR

PubMed Central

Lucchi, Naomi W.; Narayanan, Jothikumar; Karell, Mara A.; Xayavong, Maniphet; Kariuki, Simon; DaSilva, Alexandre J.; Hill, Vincent; Udhayakumar, Venkatachalam

2013-01-01

There is a critical need for developing new malaria diagnostic tools that are sensitive, cost effective and capable of performing large scale diagnosis. The real-time PCR methods are particularly robust for large scale screening and they can be used in malaria control and elimination programs. We have designed novel self-quenching photo-induced electron transfer (PET) fluorogenic primers for the detection of P. falciparum and the Plasmodium genus by real-time PCR. A total of 119 samples consisting of different malaria species and mixed infections were used to test the utility of the novel PET-PCR primers in the diagnosis of clinical samples. The sensitivity and specificity were calculated using a nested PCR as the gold standard and the novel primer sets demonstrated 100% sensitivity and specificity. The limits of detection for P. falciparum was shown to be 3.2 parasites/µl using both Plasmodium genus and P. falciparum-specific primers and 5.8 parasites/µl for P. ovale, 3.5 parasites/µl for P. malariae and 5 parasites/µl for P. vivax using the genus specific primer set. Moreover, the reaction can be duplexed to detect both Plasmodium spp. and P. falciparum in a single reaction. The PET-PCR assay does not require internal probes or intercalating dyes which makes it convenient to use and less expensive than other real-time PCR diagnostic formats. Further validation of this technique in the field will help to assess its utility for large scale screening in malaria control and elimination programs. PMID:23437209

Programmed cell death in trypanosomatids and other unicellular organisms.

PubMed

Debrabant, Alain; Lee, Nancy; Bertholet, Sylvie; Duncan, Robert; Nakhasi, Hira L

2003-03-01

In multicellular organisms, cellular growth and development can be controlled by programmed cell death (PCD), which is defined by a sequence of regulated events. However, PCD is thought to have evolved not only to regulate growth and development in multicellular organisms but also to have a functional role in the biology of unicellular organisms. In protozoan parasites and in other unicellular organisms, features of PCD similar to those in multicellular organisms have been reported, suggesting some commonality in the PCD pathway between unicellular and multicellular organisms. However, more extensive studies are needed to fully characterise the PCD pathway and to define the factors that control PCD in the unicellular organisms. The understanding of the PCD pathway in unicellular organisms could delineate the evolutionary origin of this pathway. Further characterisation of the PCD pathway in the unicellular parasites could provide information regarding their pathogenesis, which could be exploited to target new drugs to limit their growth and treat the disease they cause.

Role of parasitic vaccines in integrated control of parasitic diseases in livestock

PubMed Central

Sharma, Neelu; Singh, Veer; Shyma, K. P.

2015-01-01

Parasitic infections adversely affect animal’s health and threaten profitable animal production, thus affecting the economy of our country. These infections also play a major role in the spread of zoonotic diseases. Parasitic infections cause severe morbidity and mortality in animals especially those affecting the gastrointestinal system and thus affect the economy of livestock owner by decreasing the ability of the farmer to produce economically useful animal products. Due to all these reasons proper control of parasitic infection is critically important for sustained animal production. The most common and regularly used method to control parasitic infection is chemotherapy, which is very effective but has several disadvantages like drug resistance and drug residues. Integrated approaches to control parasitic infections should be formulated including grazing management, biological control, genetic resistance of hosts, and parasitic vaccines. India ranks first in cattle and buffalo population, but the majority of livestock owners have fewer herds, so other measures like grazing management, biological control, genetic resistance of hosts are not much practical to use. The most sustainable and economical approach to control parasitic infection in our country is to vaccinate animals, although vaccines increase the initial cost, but the immunity offered by the vaccine are long lived. Thus, vaccination of animals for various clinical, chronic, subclinical parasitic infections will be a cheaper and effective alternative to control parasitic infection for long time and improve animal production. PMID:27047140

Cowbird removals unexpectedly increase productivity of a brood parasite and the songbird host.

PubMed

Kosciuch, Karl L; Sandercock, Brett K

2008-03-01

Generalist brood parasites reduce productivity and population growth of avian hosts and have been implicated in population declines of several songbirds of conservation concern. To estimate the demographic effects of brood parasitism on Bell's Vireos (Vireo bellii), we removed Brown-headed Cowbirds (Molothrus ater) in a replicated switchback experimental design. Cowbird removals decreased parasitism frequency from 77% and 85% at unmanipulated plots to 58% and 47% at removal plots in 2004 and 2005, respectively. Vireo productivity per pair was higher at cowbird removal plots when years were pooled (mean = 2.6 +/- 0.2 [SE] young per pair) compared to unmanipulated plots (1.2 +/- 0.1). Nest desertion frequency was lower at cowbird removal plots (35% of parasitized nests) compared to unmanipulated plots (69%) because removal of host eggs was the proximate cue for nest desertion, and vireos experienced lower rates of egg loss at cowbird removal plots. Nest success was higher among unparasitized than parasitized nests, and parasitized nests at cowbird removal plots had a higher probability of success than parasitized nests at unmanipulated plots. Unexpectedly, cowbird productivity from vireo pairs was higher at cowbird removal plots (mean = 0.3 +/- 0.06 young per pair) than at unmanipulated plots (0.1 +/- 0.03) because fewer parasitized nests were deserted and the probability of nest success was higher. Our study provides the first evidence that increases in cowbird productivity may be an unintended consequence of cowbird control programs, especially during the initial years of trapping when parasitism may only be moderately reduced. Thus, understanding the demographic impacts of cowbird removals requires an informed understanding of the behavioral ecology of host-parasite interactions.

Stray Cats Gastrointestinal Parasites and its Association With Public Health in Ahvaz City, South Western of Iran

PubMed Central

Khademvatan, Shahram; Abdizadeh, Rahman; Rahim, Fakher; Hashemitabar, Mahamoud; Ghasemi, Mohammad; Tavalla, Mahdi

2014-01-01

Background: Cats are the hosts for some zoonotic parasites such as Toxoplasma gondii and Toxocara spp. which are important in medicine and veterinary. Studies on the prevalence of intestinal parasites of cats have received little attention in south west of Iran. Objectives: The current study aimed to investigate the prevalence of parasites in stray cats in Ahvaz. Materials and Methods: Random sampling was carried out from January to May 2012. One hundred and forty fecal samples from stray cats were examined using sucrose flotation method. Results: Gastrointestinal parasites were found in 121 of the 140 (86.4%) examined samples. The parasites detected in stray cats were Toxocara spp. (45%, 63/140), Isospora spp. (21.4%, 30/140), nematode larvae (21.4%, 30/140), Taenia spp. (18.6%, 26/140), Sarcocystis spp. (17.1%, 24/140), Eimeria spp. (15%, 21/140), Blastocystis spp. (14.3%, 20/140), Giardia spp, (10.7%, 15/140), Physaloptera spp. (7.1%, 10/140), and amoeba cyst (5.7%, 8/140) respectively. The prevalence of infection by Joyexiella spp. and hook worms (4.3%, 6/140), for example, Dipylidium caninum (2.9%, 4/140) was similar; and the prevalence of infection by T. gondii and Dicrocoelium dendriticum was similar (1.4%, 2/140). Conclusions: Since the prevalence of zoonotic gastrointestinal parasites such as Toxocara spp. in stray cats is high, there is a need to plan adequate programs to control these zoonotic parasites. PMID:25485047

World Epidemiology Review, Number 103.

DTIC Science & Technology

1978-08-30

meeting. One of the papers dealt with a special research done on gastro- intestinal parasites on Speaking about other issues discussed...Reported (EL DIA, 28 Jul 78) 32 DENMARK Government To Tighten Control Over Use of Animal Medicines (POLITIKEN, 21 Jul 78) 34 ETHIOPIA ... ETHIOPIA Briefs Locust Invasion 44 GHANA FRG To Finance Tsetse Fly Control Program (Clement Asante; GHANAIAN TIMES, 2 Aug 78) 45 HUNGARY Briefs

25 CFR 700.723 - Control of livestock disease and parasites.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 25 Indians 2 2011-04-01 2011-04-01 false Control of livestock disease and parasites. 700.723... RELOCATION PROCEDURES New Lands Grazing § 700.723 Control of livestock disease and parasites. Whenever livestock within the New Lands become infected with contagious or infectious disease or parasites or have...

25 CFR 700.723 - Control of livestock disease and parasites.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 25 Indians 2 2010-04-01 2010-04-01 false Control of livestock disease and parasites. 700.723... RELOCATION PROCEDURES New Lands Grazing § 700.723 Control of livestock disease and parasites. Whenever livestock within the New Lands become infected with contagious or infectious disease or parasites or have...

25 CFR 700.723 - Control of livestock disease and parasites.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 25 Indians 2 2014-04-01 2014-04-01 false Control of livestock disease and parasites. 700.723... RELOCATION PROCEDURES New Lands Grazing § 700.723 Control of livestock disease and parasites. Whenever livestock within the New Lands become infected with contagious or infectious disease or parasites or have...

25 CFR 700.723 - Control of livestock disease and parasites.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 25 Indians 2 2013-04-01 2013-04-01 false Control of livestock disease and parasites. 700.723... RELOCATION PROCEDURES New Lands Grazing § 700.723 Control of livestock disease and parasites. Whenever livestock within the New Lands become infected with contagious or infectious disease or parasites or have...

25 CFR 700.723 - Control of livestock disease and parasites.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 25 Indians 2 2012-04-01 2012-04-01 false Control of livestock disease and parasites. 700.723... RELOCATION PROCEDURES New Lands Grazing § 700.723 Control of livestock disease and parasites. Whenever livestock within the New Lands become infected with contagious or infectious disease or parasites or have...

Assessing assessment: Can the expected effects of the St. Marys River sea lamprey control strategy be detected?

USGS Publications Warehouse

Adams, Jean V.; Bergstedt, Roger A.; Christie, Gavin C.; Cuddy, Douglas W.; Fodale, Michael F.; Heinrich, John W.; Jones, Michael L.; McDonald, Rodney B.; Mullett, Katherine M.; Young, Robert J.

2003-01-01

In 1997 the Great Lakes Fishery Commission approved a 5-year (1998 to 2002) control strategy to reduce sea lamprey (Petromyzon marinus) production in the St. Marys River, the primary source of parasitic sea lampreys in northern Lake Huron. An assessment plan was developed to measure the success of the control strategy and decide on subsequent control efforts. The expected effects of the St. Marys River control strategy are described, the assessments in place to measure these effects are outlined, and the ability of these assessments to detect the expected effects are quantified. Several expected changes were predicted to be detectable: abundance of parasitic-phase sea lampreys and annual mortality of lake trout (Salvelinus namaycush) by 2001, abundance of spawning-phase sea lampreys by 2002, and relative return rates of lake trout and sea lamprey wounding rates on lake trout by 2005. Designing an effective assessment program to quantify the consequences of fishery management actions is a critical, but often overlooked ingredient of sound fisheries management.

Effect of Insecticide Regimens on Biological Control of the Tarnished Plant Bug, Lygus lineolaris, by Peristenus spp. in New York State Apple Orchards

PubMed Central

Crampton, Lora A.; Loeb, Greg M.; Hoelmer, Kim A.; Hoffmann, Michael P.

2010-01-01

To improve biological control of Lygus lineolaris (Palisot de Beauvois) (Hemiptera: Miridae), the European parasitoid Peristenus digoneutis Loan (Hymenoptera: Braconidae) was introduced into the US in the 1980's and has become established in forage alfalfa, strawberries and apples. The objective of this study was to determine how four different insecticide management regimes affected parasitism of L. lineolaris by Peristenus spp. During the summers of 2005 and 2006, L. lineolaris nymphs were collected from New York State apple orchards using industry standard, reduced risk, and organically approved insecticides only. A ‘no insecticide’ (abandoned orchard) treatment was also included in 2006. Rates of parasitism of L. lineolaris nymphs were determined using a DNA-based laboratory technique. Results indicated that insecticide treatment had a significant effect on rates of parasitism of L. lineolaris by Peristenus spp. Compared to the industry standard treatment, rates of parasitism were higher in reduced risk orchards and lower in organic orchards. These results suggest that it is difficult to predict a priori the consequences of insecticide programs and point to the need to take into consideration the specific pests and beneficial organisms involved as well as the crop and the specific insecticides being applied. PMID:20578957

Assessment of nurses' performance related to control of some parasites acquired from fresh vegetables as a patient safety measure in a military hospital.

PubMed

Ahmed Saleh, Ahmed Megahed; El-Raouf Ali, Hisham Abd; Mohamed Ahmed, Salwa Abdalla; Mohamed, Naglaa Elsaid; Morsy, Tosson A

2014-12-01

Foodborne parasitic infection in the hospital constitutes a major health problem particularly for patients who are more vulnerable than healthy subjects to parasitic risks. Parasitic infection. represents an area of concern for advanced practice nurse. The work assessed the military nursing staff performance regarding the nosocomial food-borne parasitic infection control. Research design; A descriptive research design was used to identify knowledge, attitudes and practice of nurses related to nosocomial food-borne parasitic infection control measures. The study was conducted at a general military hospital. 50 nurses, the whole available number who covered the inclusion, criteria. DATA COLLECTION TOOLS: It included; (1): Structured interview sheet was constructed after reviewing the relevant literature to elicit information, it included two parts a) subjects' sociodemographic characteristics b) nurses' knowledge regarding nosocomial parasites infections. (2): RATING SCALE: to assess attitude of nursing staff towards nosocomial parasites infections and its prevention. (3): Obselrvational CHECKLIST: to assess the nurses' practice of self-protection and' control of nosocomial parasitic' infections control measures.. A statistically insignificant difference between knowledge levels about nosocomial parasites infection among military nurses. More than half of participant nurses had positive attitude towards nosoconijal parasite infection control and prevention without significant difference between all topics (P>0.056). That most participant nurses had unsatisfactory practice to infection control measures with significant lower score for procurement, storage and preparation of raw material followed by personal hygiene (P<0.05). Nurses in all roles and settings can demonstrate leadership in infection prevention. and control by using their knowledge, skill and judgment to initiate appropriate and immediate infection control procedures.

[Challenge and strategy of prevention and control of important parasitic diseases under the Belt and Road Initiative].

PubMed

Chun-Li, Cao; Jia-Gang, Guo

2018-04-17

China was once a country with the heaviest burden of parasitic diseases. Under the leadership of the Communist Party and national authority, after more than 60 years' efforts of prevention and control, the remarkable results have been achieved in China. However, affected by the social and economic development and environmental changes, the prevention and control of parasitic diseases, especially imported parasitic diseases, are facing new challenges, and the parasitic diseases, such as malaria, schistosomiasis, leishmaniasis, filariasis and trypanosomiasis, appear increasingly. With the development of the Belt and Road Initiative, the transmission risks of these diseases are more increased. The purpose of this paper is to describe the experience and results of parasitic disease prevention and control in China, understand the present parasitic disease epidemic situation of the Belt and Road Initiative related countries, analyze the transmission risks of important parasitic diseases, and present some relevant suggestions, so as to provide the evidence for the health administrative department formulating the prevention and control strategies of such parasitic diseases timely and effectively.

[Performance assessment employing slide sets: A tool for the classification of senior microscopists from Colombia´s Malaria Control Program].

PubMed

Mendoza, Nohora Marcela; González, Nohora Elizabeth

2015-01-01

One of the most important activities for quality assurance of malaria diagnosis is performance assessment. In Colombia, performance assessment of malaria microscopists has been done through the external performance assessment and indirect external performance assessment programs. To assess the performance of malaria microscopists of public reference laboratories using slide sets, and to describe the methodology used for this purpose. This was a retrospective study to evaluate the concordance of senior microscopists regarding parasite detection, species identification and parasite count based on the results of the assessment of competences using two sets, one comprising 40 slides, and another one with 17 slides. The concordance for parasite detection was 96.9% (95% CI: 96.0-97.5) and 88.7% (95% CI: 86.6-90.5) for species identification. The average percentage of concordant slides in the group evaluated was 89.7% (95% CI: 87.5-91.6). Most of the senior microscopists in Colombia were classified in the two top categories in the performance assessment using slide sets. The most common difficulty encountered was the identification of parasite species. The use of this tool to assess individual performance of microscopists in the evaluation of samples with different degrees of difficulty allows for characterizing the members of the malaria diagnosis network and strengthening the abilities of those who require it.

Host-mediated impairment of parasite maturation during blood-stage Plasmodium infection

PubMed Central

Khoury, David S.; Cromer, Deborah; Akter, Jasmin; Sebina, Ismail; Elliott, Trish; Thomas, Bryce S.; Soon, Megan S. F.; James, Kylie R.; Best, Shannon E.; Haque, Ashraful; Davenport, Miles P.

2017-01-01

Severe malaria and associated high parasite burdens occur more frequently in humans lacking robust adaptive immunity to Plasmodium falciparum. Nevertheless, the host may partly control blood-stage parasite numbers while adaptive immunity is gradually established. Parasite control has typically been attributed to enhanced removal of parasites by the host, although in vivo quantification of this phenomenon remains challenging. We used a unique in vivo approach to determine the fate of a single cohort of semisynchronous, Plasmodium berghei ANKA- or Plasmodium yoelii 17XNL-parasitized red blood cells (pRBCs) after transfusion into naive or acutely infected mice. As previously shown, acutely infected mice, with ongoing splenic and systemic inflammatory responses, controlled parasite population growth more effectively than naive controls. Surprisingly, however, this was not associated with accelerated removal of pRBCs from circulation. Instead, transfused pRBCs remained in circulation longer in acutely infected mice. Flow cytometric assessment and mathematical modeling of intraerythrocytic parasite development revealed an unexpected and substantial slowing of parasite maturation in acutely infected mice, extending the life cycle from 24 h to 40 h. Importantly, impaired parasite maturation was the major contributor to control of parasite growth in acutely infected mice. Moreover, by performing the same experiments in rag1−/− mice, which lack T and B cells and mount weak inflammatory responses, we revealed that impaired parasite maturation is largely dependent upon the host response to infection. Thus, impairment of parasite maturation represents a host-mediated, immune system-dependent mechanism for limiting parasite population growth during the early stages of an acute blood-stage Plasmodium infection. PMID:28673996

Selective therapy in equine parasite control--application and limitations.

PubMed

Nielsen, M K; Pfister, K; von Samson-Himmelstjerna, G

2014-05-28

Since the 1960s equine parasite control has relied heavily on frequent anthelmintic treatments often applied with frequent intervals year-round. However, increasing levels of anthelmintic resistance in cyathostomins and Parascaris equorum are now forcing the equine industry to change to a more surveillance-based treatment approach to facilitate a reduction in treatment intensity. The principle of selective therapy has been implemented with success in small ruminant parasite control, and has also found use in horse populations. Typically, egg counts are performed from all individuals in the population, and those exceeding a predetermined cutoff threshold are treated. Several studies document the applicability of this method in populations of adult horses, where the overall cyathostomin egg shedding can be controlled by only treating about half the horses. However, selective therapy has not been evaluated in foals and young horses, and it remains unknown whether the principle is adequate to also provide control over other important parasites such as tapeworms, ascarids, and large strongyles. One recent study associated selective therapy with increased occurrence of Strongylus vulgaris. Studies are needed to evaluate potential health risks associated with selective therapy, and to assess to which extent development of anthelmintic resistance can be delayed with this approach. The choice of strongyle egg count cutoff value for anthelmintic treatment is currently based more on tradition than science, and a recent publication illustrated that apparently healthy horses with egg counts below 100 eggs per gram (EPG) can harbor cyathostomin burdens in the range of 100,000 luminal worms. It remains unknown whether leaving such horses untreated constitutes a potential threat to equine health. The concept of selective therapy has merit for equine strongyle control, but several questions remain as it has not been fully scientifically evaluated. There is a great need for new and improved methods for diagnosis and surveillance to supplement or replace the fecal egg counts, and equine health parameters need to be included in studies evaluating any parasite control program. Copyright © 2014 Elsevier B.V. All rights reserved.

Programmed death 1-mediated T cell exhaustion during visceral leishmaniasis impairs phagocyte function.

PubMed

Esch, Kevin J; Juelsgaard, Rachel; Martinez, Pedro A; Jones, Douglas E; Petersen, Christine A

2013-12-01

Control of Leishmania infantum infection is dependent upon Th1 CD4(+) T cells to promote macrophage intracellular clearance of parasites. Deficient CD4(+) T cell effector responses during clinical visceral leishmaniasis (VL) are associated with elevated production of IL-10. In the primary domestic reservoir of VL, dogs, we define occurrence of both CD4(+) and CD8(+) T cell exhaustion as a significant stepwise loss of Ag-specific proliferation and IFN-γ production, corresponding to increasing VL symptoms. Exhaustion was associated with a 4-fold increase in the population of T cells with surface expression of programmed death 1 (PD-1) between control and symptomatic populations. Importantly, exhausted populations of CD8(+) T cells and to a lesser extent CD4(+) T cells were present prior to onset of clinical VL. VL-exhausted T cells did not undergo significant apoptosis ex vivo after Ag stimulation. Ab block of PD-1 ligand, B7.H1, promoted return of CD4(+) and CD8(+) T cell function and dramatically increased reactive oxygen species production in cocultured monocyte-derived phagocytes. As a result, these phagocytes had decreased parasite load. To our knowledge, we demonstrate for the first time that pan-T cell, PD-1-mediated, exhaustion during VL influenced macrophage-reactive oxygen intermediate production. Blockade of the PD-1 pathway improved the ability of phagocytes isolated from dogs presenting with clinical VL to clear intracellular parasites. T cell exhaustion during symptomatic canine leishmaniasis has implications for the response to vaccination and therapeutic strategies for control of Leishmania infantum in this important reservoir species.

Evolution of apoptosis-like programmed cell death in unicellular protozoan parasites.

PubMed

Kaczanowski, Szymon; Sajid, Mohammed; Reece, Sarah E

2011-03-25

Apoptosis-like programmed cell death (PCD) has recently been described in multiple taxa of unicellular protists, including the protozoan parasites Plasmodium, Trypanosoma and Leishmania. Apoptosis-like PCD in protozoan parasites shares a number of morphological features with programmed cell death in multicellular organisms. However, both the evolutionary explanations and mechanisms involved in parasite PCD are poorly understood. Explaining why unicellular organisms appear to undergo 'suicide' is a challenge for evolutionary biology and uncovering death executors and pathways is a challenge for molecular and cell biology. Bioinformatics has the potential to integrate these approaches by revealing homologies in the PCD machinery of diverse taxa and evaluating their evolutionary trajectories. As the molecular mechanisms of apoptosis in model organisms are well characterised, and recent data suggest similar mechanisms operate in protozoan parasites, key questions can now be addressed. These questions include: which elements of apoptosis machinery appear to be shared between protozoan parasites and multicellular taxa and, have these mechanisms arisen through convergent or divergent evolution? We use bioinformatics to address these questions and our analyses suggest that apoptosis mechanisms in protozoan parasites and other taxa have diverged during their evolution, that some apoptosis factors are shared across taxa whilst others have been replaced by proteins with similar biochemical activities.

Evolution of apoptosis-like programmed cell death in unicellular protozoan parasites

PubMed Central

2011-01-01

Apoptosis-like programmed cell death (PCD) has recently been described in multiple taxa of unicellular protists, including the protozoan parasites Plasmodium, Trypanosoma and Leishmania. Apoptosis-like PCD in protozoan parasites shares a number of morphological features with programmed cell death in multicellular organisms. However, both the evolutionary explanations and mechanisms involved in parasite PCD are poorly understood. Explaining why unicellular organisms appear to undergo 'suicide' is a challenge for evolutionary biology and uncovering death executors and pathways is a challenge for molecular and cell biology. Bioinformatics has the potential to integrate these approaches by revealing homologies in the PCD machinery of diverse taxa and evaluating their evolutionary trajectories. As the molecular mechanisms of apoptosis in model organisms are well characterised, and recent data suggest similar mechanisms operate in protozoan parasites, key questions can now be addressed. These questions include: which elements of apoptosis machinery appear to be shared between protozoan parasites and multicellular taxa and, have these mechanisms arisen through convergent or divergent evolution? We use bioinformatics to address these questions and our analyses suggest that apoptosis mechanisms in protozoan parasites and other taxa have diverged during their evolution, that some apoptosis factors are shared across taxa whilst others have been replaced by proteins with similar biochemical activities. PMID:21439063

Refined stratified-worm-burden models that incorporate specific biological features of human and snail hosts provide better estimates of Schistosoma diagnosis, transmission, and control.

PubMed

Gurarie, David; King, Charles H; Yoon, Nara; Li, Emily

2016-08-04

Schistosoma parasites sustain a complex transmission process that cycles between a definitive human host, two free-swimming larval stages, and an intermediate snail host. Multiple factors modify their transmission and affect their control, including heterogeneity in host populations and environment, the aggregated distribution of human worm burdens, and features of parasite reproduction and host snail biology. Because these factors serve to enhance local transmission, their inclusion is important in attempting accurate quantitative prediction of the outcomes of schistosomiasis control programs. However, their inclusion raises many mathematical and computational challenges. To address these, we have recently developed a tractable stratified worm burden (SWB) model that occupies an intermediate place between simpler deterministic mean worm burden models and the very computationally-intensive, autonomous agent models. To refine the accuracy of model predictions, we modified an earlier version of the SWB by incorporating factors representing essential in-host biology (parasite mating, aggregation, density-dependent fecundity, and random egg-release) into demographically structured host communities. We also revised the snail component of the transmission model to reflect a saturable form of human-to-snail transmission. The new model allowed us to realistically simulate overdispersed egg-test results observed in individual-level field data. We further developed a Bayesian-type calibration methodology that accounted for model and data uncertainties. The new model methodology was applied to multi-year, individual-level field data on S. haematobium infections in coastal Kenya. We successfully derived age-specific estimates of worm burden distributions and worm fecundity and crowding functions for children and adults. Estimates from the new SWB model were compared with those from the older, simpler SWB with some substantial differences noted. We validated our new SWB estimates in prediction of drug treatment-based control outcomes for a typical Kenyan community. The new version of the SWB model provides a better tool to predict the outcomes of ongoing schistosomiasis control programs. It reflects parasite features that augment and perpetuate transmission, while it also readily incorporates differences in diagnostic testing and human sub-population differences in treatment coverage. Once extended to other Schistosoma species and transmission environments, it will provide a useful and efficient tool for planning control and elimination strategies.

Precision QTL mapping of downy mildew resistance in Hop (Humulus lupulus L.)

USDA-ARS?s Scientific Manuscript database

Hop Downy mildew (DM) is an obligate parasite causing severe losses in hop if not controlled. Resistance to this pathogen is a primary goal for hop breeding programs. The objective of this study was to identify QTLs linked to DM resistance. Next-generation-sequencing was performed on a mapping po...

No apparent reduction in schistosome burden or genetic diversity following four years of school-based mass drug administration in mwea, central kenya, a heavy transmission area.

PubMed

Lelo, Agola E; Mburu, David N; Magoma, Gabriel N; Mungai, Ben N; Kihara, Jimmy H; Mwangi, Ibrahim N; Maina, Geoffrey M; Kinuthia, Joseph M; Mutuku, Martin W; Loker, Eric S; Mkoji, Gerald M; Steinauer, Michelle L

2014-10-01

Schistosomiasis is a debilitating neglected tropical disease that infects over 200 million people worldwide. To combat this disease, in 2012, the World Health Organization announced a goal of reducing and eliminating transmission of schistosomes. Current control focuses primarily on mass drug administration (MDA). Therefore, we monitored transmission of Schistosoma mansoni via fecal egg counts and genetic markers in a typical school based MDA setting to ascertain the actual impacts of MDA on the targeted schistosome population. For 4 years, we followed 67 children enrolled in a MDA program in Kenya. Infection status and egg counts were measured each year prior to treatment. For 15 of these children, for which there was no evidence of acquired resistance, meaning they became re-infected following each treatment, we collected microsatellite genotype data from schistosomes passed in fecal samples as a representation of the force of transmission between drug treatments. We genotyped a total of 4938 parasites from these children, with an average of 329.2 parasites per child for the entire study, and an average of 82.3 parasites per child per annual examination. We compared prevalence, egg counts, and genetic measures including allelic richness, gene diversity (expected heterozygosity), adult worm burdens and effective number of breeders among time points to search for evidence for a change in transmission or schistosome populations during the MDA program. We found no evidence of reduced transmission or schistosome population decline over the course of the program. Although prevalence declined in the 67 children as it did in the overall program, reinfection rates were high, and for the 15 children studied in detail, schistosome egg counts and estimated adult worm burdens did not decline between years 1 and 4, and genetic diversity increased over the course of drug treatment. School based control programs undoubtedly improve the health of individuals; however, our data show that in an endemic area, such a program has had no obvious effect on reducing transmission or of significantly impacting the schistosome population as sampled by the children we studied in depth. Results like these, in combination with other sources of information, suggest more integrated approaches for interrupting transmission and significantly diminishing schistosome populations will be required to achieve sustainable control.

Prevalence of zoonotic intestinal parasites in domestic and stray dogs in a rural area of Iran.

PubMed

Beiromvand, Molouk; Akhlaghi, Lame; Fattahi Massom, Seyed Hossein; Meamar, Ahmad Reza; Motevalian, Abbas; Oormazdi, Hormozd; Razmjou, Elham

2013-04-01

Certain zoonotic parasites are enteropathogens in dogs that cause serious human disease such as cystic echinococcosis, human alveolar echinococcosis, visceral larva migrans, and ocular larva migrans. This study investigated the prevalence of intestinal parasites in dogs in the Chenaran County, Razavi Khorasan Province, Iran. Sampling was carried out randomly in 17 villages from November 2009 to January 2010. Seventy-seven fecal samples from 28 domestic and 49 stray dogs were examined using sieving/flotation and modified Ziehl-Neelsen staining. Intestinal parasites were found in 51 of the 77 (66%) dogs most common being Toxascaris leonina (29%, 22/77), Toxocara spp. (25%, 19/77), Eimeria spp. (19%, 15/77), Taenia/Echinococcus spp. (18%, 14/77), Sarcocystis spp. (17%, 13/77), and Dicrocoelium dendriticum (14%, 11/77). Lower infection rates of parasites were observed for Trichuris vulpis (6%, 5/77), Cryptosporidium spp. (5%, 4/77), and Physaloptera spp. (3%, 2/77). Prevalence of infection by Dipylidium caninum, Capillaria spp., Cystoisospora spp., and hookworms was similar (1%, 1/77). This study is the first report of the prevalence of intestinal parasites of domestic and stray dogs in Chenaran County, Northeast Iran. The higher prevalence of zoonotic intestinal parasites such as Toxascaris leonina, Toxocara spp. and Taenia/Echinococcus spp. compared to other parasites indicates the need for control programs to minimize the risk of transmission of zoonotic disease, particularly cystic echinococcosis, alveolar echinococcosis, visceral larva migrans, and ocular larva migrans to people living in these areas. Copyright © 2012 Elsevier B.V. All rights reserved.

A cross-sectional study on intestinal parasitic infections in rural communities, northeast Thailand.

PubMed

Boonjaraspinyo, Sirintip; Boonmars, Thidarut; Kaewsamut, Butsara; Ekobol, Nuttapon; Laummaunwai, Porntip; Aukkanimart, Ratchadawan; Wonkchalee, Nadchanan; Juasook, Amornrat; Sriraj, Pranee

2013-12-01

Despite the existence of effective anthelmintics, parasitic infections remain a major public health problem in Southeast Asia, including Thailand. In rural communities, continuing infection is often reinforced by dietary habits that have a strong cultural basis and by poor personal hygiene and sanitation. This study presents a survey of the prevalence of intestinal parasitic infections among the people in rural Thailand. The community-based cross-sectional study was conducted in villages in Khon Kaen Province, northeastern Thailand, from March to August 2013. A total of 253 stool samples from 102 males and 140 females, aged 2-80 years, were prepared using formalin-ethyl acetate concentration methods and examined using light microscopy. Ninety-four individuals (37.2%) were infected with 1 or more parasite species. Presence of parasitic infection was significantly correlated with gender (P=0.001); nearly half of males in this survey (49.0%) were infected. Older people had a higher prevalence than younger members of the population. The most common parasite found was Opisthorchis viverrini (26.9%), followed by Strongyloides stercoralis (9.5%), Taenia spp. (1.6%), echinostomes (0.4%), and hookworms (0.4%). The prevalence of intestinal protozoa was Blastocystis hominis 1.6%, Entamoeba histolytica 0.8%, Entamoeba coli 0.8%, Balantidium coli 0.4%, Iodamoeba bütschlii 0.4%, and Sarcocystis hominis 0.4%. Co-infections of various helminths and protozoa were present in 15.9% of the people. The present results show that the prevalence of parasitic infections in this region is still high. Proactive education about dietary habits, personal hygiene, and sanitation should be provided to the people in this community to reduce the prevalence of intestinal parasite infections. Moreover, development of policies and programs to control parasites is needed.

A Cross-Sectional Study on Intestinal Parasitic Infections in Rural Communities, Northeast Thailand

PubMed Central

Boonjaraspinyo, Sirintip; Kaewsamut, Butsara; Ekobol, Nuttapon; Laummaunwai, Porntip; Aukkanimart, Ratchadawan; Wonkchalee, Nadchanan; Juasook, Amornrat; Sriraj, Pranee

2013-01-01

Despite the existence of effective anthelmintics, parasitic infections remain a major public health problem in Southeast Asia, including Thailand. In rural communities, continuing infection is often reinforced by dietary habits that have a strong cultural basis and by poor personal hygiene and sanitation. This study presents a survey of the prevalence of intestinal parasitic infections among the people in rural Thailand. The community-based cross-sectional study was conducted in villages in Khon Kaen Province, northeastern Thailand, from March to August 2013. A total of 253 stool samples from 102 males and 140 females, aged 2-80 years, were prepared using formalin-ethyl acetate concentration methods and examined using light microscopy. Ninety-four individuals (37.2%) were infected with 1 or more parasite species. Presence of parasitic infection was significantly correlated with gender (P=0.001); nearly half of males in this survey (49.0%) were infected. Older people had a higher prevalence than younger members of the population. The most common parasite found was Opisthorchis viverrini (26.9%), followed by Strongyloides stercoralis (9.5%), Taenia spp. (1.6%), echinostomes (0.4%), and hookworms (0.4%). The prevalence of intestinal protozoa was Blastocystis hominis 1.6%, Entamoeba histolytica 0.8%, Entamoeba coli 0.8%, Balantidium coli 0.4%, Iodamoeba bütschlii 0.4%, and Sarcocystis hominis 0.4%. Co-infections of various helminths and protozoa were present in 15.9% of the people. The present results show that the prevalence of parasitic infections in this region is still high. Proactive education about dietary habits, personal hygiene, and sanitation should be provided to the people in this community to reduce the prevalence of intestinal parasite infections. Moreover, development of policies and programs to control parasites is needed. PMID:24516280

[Intestinal parasitosis among non-permanent resident students in Tunisia: a review of 23 years of monitoring in the department of Parasitology-Mycology at the Rabta Hospital of Tunisia].

PubMed

Dridi, Kalthoum; Fakhfakh, Najla; Belhadj, Sleh; Kaouech, Emira; Kallel, Kalthoum; Chaker, Emna

2015-07-01

In order to fight digestive parasitism in Tunisia, a national program of surveillance of non-permanent resident students in Tunisia has been found to detect these parasitosis in this target population. To determine the prevalence of intestinal parasitosis among non-permanent resident students in Tunisia, to identify the different parasitic species founded and to show the interest of this screening. During a period of 23 years (1990-2012), 7386 parasitological examinations of stools has been made among students essentially from or had visited tropical Africa, Maghreb and Middle-East, at the laboratory of Parasitology-Mycology at the Rabta Hospital of Tunis. The prevalence of intestinal parasitism found was 34.45% (i.e. 2545 infested students). Among the protozoa that have been isolated in the majority of cases (78.75%), amoebae were most frequently found (86.4%) represented mainly by Entamoeba coli and Endolimax nanus in respectively, 25.62 and 23.33% of parasites isolated; while Entamoeba histolytica/dispar, only pathogenic Amoeba was found in 8.05% of the total of parasites isolated. Regarding helminths, found in 21.25% of parasites isolated, Ankylostome was predominant (34.5%) represented by the species of Necator americanus. A single case of Ancylostom duodenale has been isolated. Among the identified parasite species, 38.7% were known parasitic pathogens for humans. These results note the interest of the control of the non-permanent resident students in Tunisia. The precocious tracking and treatment of affected subjects permits to avoid the introduction and the dissemination of parasites already rare and virulent strains in our country.

Major parasitic diseases of poverty in mainland China: perspectives for better control.

PubMed

Wang, Jin-Lei; Li, Ting-Ting; Huang, Si-Yang; Cong, Wei; Zhu, Xing-Quan

2016-08-01

Significant progress has been made in the prevention, control, and elimination of human parasitic diseases in China in the past 60 years. However, parasitic diseases of poverty remain major causes of morbidity and mortality, and inflict enormous economic costs on societies.In this article, we review the prevalence rates, geographical distributions, epidemic characteristics, risk factors, and clinical manifestations of parasitic diseases of poverty listed in the first issue of the journal Infectious Diseases of Poverty on 25 October 2012. We also address the challenges facing control of parasitic diseases of poverty and provide suggestions for better control.

[Current situation of human resources of parasitic disease control and prevention organizations in Henan Province].

PubMed

Ya-Lan, Zhang; Yan-Kun, Zhu; Wei-Qi, Chen; Yan, Deng; Peng, Li

2018-01-10

To understand the current status of human resources of parasitic disease control and prevention organizations in Henan Province, so as to provide the reference for promoting the integrative ability of the prevention and control of parasitic diseases in Henan Province. The questionnaires were designed and the method of census was adopted. The information, such as the amounts, majors, education background, technical titles, working years, and turnover in each parasitic disease control and prevention organization was collected by the centers for disease control and prevention (CDCs) at all levels. The data were descriptively analyzed. Totally 179 CDCs were investigated, in which only 19.0% (34/179) had the independent parasitic diseases control institution (department) . There were only 258 full-time staffs working on parasitic disease control and prevention in the whole province, in which only 61.9% (159/258) were health professionals. Those with junior college degree or below in the health professionals accounted for 60.3% (96/159) . Most of them (42.1%) had over 20 years of experience, but 57.9% (92/159) of their technical post titles were at primary level or below. The proportion of the health professionals is low in the parasitic disease control and prevention organizations in Henan Province. The human resource construction for parasitic disease control and prevention at all levels should be strengthened.

The Emergence of Resistance to the Benzimidazole Anthlemintics in Parasitic Nematodes of Livestock Is Characterised by Multiple Independent Hard and Soft Selective Sweeps

PubMed Central

Redman, Elizabeth; Whitelaw, Fiona; Tait, Andrew; Burgess, Charlotte; Bartley, Yvonne; Skuce, Philip John; Jackson, Frank; Gilleard, John Stuart

2015-01-01

Anthelmintic resistance is a major problem for the control of parasitic nematodes of livestock and of growing concern for human parasite control. However, there is little understanding of how resistance arises and spreads or of the “genetic signature” of selection for this group of important pathogens. We have investigated these questions in the system for which anthelmintic resistance is most advanced; benzimidazole resistance in the sheep parasites Haemonchus contortus and Teladorsagia circumcincta. Population genetic analysis with neutral microsatellite markers reveals that T. circumcincta has higher genetic diversity but lower genetic differentiation between farms than H. contortus in the UK. We propose that this is due to epidemiological differences between the two parasites resulting in greater seasonal bottlenecking of H. contortus. There is a remarkably high level of resistance haplotype diversity in both parasites compared with drug resistance studies in other eukaryotic systems. Our analysis suggests a minimum of four independent origins of resistance mutations on just seven farms for H. contortus, and even more for T. circumincta. Both hard and soft selective sweeps have occurred with striking differences between individual farms. The sweeps are generally softer for T. circumcincta than H. contortus, consistent with its higher level of genetic diversity and consequent greater availability of new mutations. We propose a model in which multiple independent resistance mutations recurrently arise and spread by migration to explain the widespread occurrence of resistance in these parasites. Finally, in spite of the complex haplotypic diversity, we show that selection can be detected at the target locus using simple measures of genetic diversity and departures from neutrality. This work has important implications for the application of genome-wide approaches to identify new anthelmintic resistance loci and the likelihood of anthelmintic resistance emerging as selection pressure is increased in human soil-transmitted nematodes by community wide treatment programs. PMID:25658086

[Establishment of response system to emergency parasitic disease affairs in China].

PubMed

Chun-Li, C; Le-Ping, S; Qing-Biao, H; Bian-Li, X U; Bo, Z; Jian-Bing, L; Dan-Dan, L; Shi-Zhu, L I; Oning, X; Xiao-Nong, Z

2017-08-14

China's prevention and control of parasitic diseases has made remarkable achievements. However, the prevalence and transmission of parasitic diseases is impacted by the complicated natural and social factors of environment, natural disasters, population movements, and so on. Therefore, there are still the risks of the outbreak of emergency parasitic diseases affairs, which may affect the control effectiveness of parasitic diseases and endanger the social stability seriously. In this article, we aim at the analysis of typical cases of emergency parasitic disease affairs and their impacts on public health security in China in recently years, and we also elaborate the disposal characteristics of emergency parasitic disease affairs, and propose the establishment of response system to emergency parasitic disease affairs in China, including the organizational structure and response flow path, and in addition, point out that, in the future, we should strengthen the system construction and measures of the response system to emergency parasitic disease affairs, so as to control the risk and harm of parasitic disease spread as much as possible and to realize the early intervention and proper disposal of emergency parasitic disease affairs.

Snail-borne parasitic diseases: an update on global epidemiological distribution, transmission interruption and control methods.

PubMed

Lu, Xiao-Ting; Gu, Qiu-Yun; Limpanont, Yanin; Song, Lan-Gui; Wu, Zhong-Dao; Okanurak, Kamolnetr; Lv, Zhi-Yue

2018-04-09

Snail-borne parasitic diseases, such as angiostrongyliasis, clonorchiasis, fascioliasis, fasciolopsiasis, opisthorchiasis, paragonimiasis and schistosomiasis, pose risks to human health and cause major socioeconomic problems in many tropical and sub-tropical countries. In this review we summarize the core roles of snails in the life cycles of the parasites they host, their clinical manifestations and disease distributions, as well as snail control methods. Snails have four roles in the life cycles of the parasites they host: as an intermediate host infected by the first-stage larvae, as the only intermediate host infected by miracidia, as the first intermediate host that ingests the parasite eggs are ingested, and as the first intermediate host penetrated by miracidia with or without the second intermediate host being an aquatic animal. Snail-borne parasitic diseases target many organs, such as the lungs, liver, biliary tract, intestines, brain and kidneys, leading to overactive immune responses, cancers, organ failure, infertility and even death. Developing countries in Africa, Asia and Latin America have the highest incidences of these diseases, while some endemic parasites have developed into worldwide epidemics through the global spread of snails. Physical, chemical and biological methods have been introduced to control the host snail populations to prevent disease. In this review, we summarize the roles of snails in the life cycles of the parasites they host, the worldwide distribution of parasite-transmitting snails, the epidemiology and pathogenesis of snail-transmitted parasitic diseases, and the existing snail control measures, which will contribute to further understanding the snail-parasite relationship and new strategies for controlling snail-borne parasitic diseases.

Knowledge, attitudes, and practices regarding cystic echinococcosis and sheep herding in Peru: a mixed-methods approach.

PubMed

Merino, Veronika; Westgard, Christopher M; Bayer, Angela M; García, Patricia J

2017-07-06

The parasitic disease, cystic echinococcosis (CE), is prevalent in low-income, livestock-raising communities and 2000 new people will be diagnosed this year in South America alone. The disease usually passes from livestock to dogs to humans, making it a zoonotic disease and part of the One Health Initiative. Control of CE has been infamously difficult; no endemic areas of South America have succeeded in maintaining sustainable eradication of the parasite. For the current study, we aimed to gain a better understanding of the knowledge, attitudes, and practices of rural sheep farmers and other community leaders regarding their sheep herding practices and perspectives about a control program for CE. We also hope to identify potential barriers and opportunities that could occur in a control program. The authors conducted Knowledge, Attitude and Practices (KAP) surveys and semi-structured interviews in rural communities in the highlands of Peru. The KAP surveys were administered to 51 local shepherds, and the semi-structured interviews were administered to 40 individuals, including shepherds, community leaders, and health care providers. We found that the shepherds already deworm their sheep at a median of 2 times per year (N = 49, range 2-4) and have a mean willingness-to-pay of U.S. $ 0.60 for dog dewormer medication (N = 20, range = 0.00- $2.00 USD). We were not able to learn the deworming agent or agents that were being used, for neither sheep nor dogs. Additionally, 90% of shepherds slaughter their own sheep (N = 49). We also learned that the main barriers to an effective control program include: lack of education about the cause and control options for CE, accessibility to the distant communities and sparse grazing pastures, and a lack of economic incentive. Findings suggest it may be feasible to develop an effective CE control program which can be used to create an improved protocol to control CE in the region.

Point of care diagnosis of multiple schistosome parasites: Species-specific DNA detection in urine by loop-mediated isothermal amplification (LAMP).

PubMed

Lodh, Nilanjan; Mikita, Kei; Bosompem, Kwabena M; Anyan, William K; Quartey, Joseph K; Otchere, Joseph; Shiff, Clive J

2017-09-01

Schistosomes are easily transmitted and high chance of repeat infection, so if control strategies based on targeted mass drug administration (MDA) are to succeed it is essential to have a test that is sensitive, accurate and simple to use. It is known and regularly demonstrated that praziquantel does not always eliminate an infection so in spite of the successes of control programs a residual of the reservoir survives to re-infect snails. The issue of diagnostic sensitivity becomes more critical in the assessment of program effectiveness. While serology, such as antigen capture tests might improve sensitivity, it has been shown that the presence of species-specific DNA fragments will indicate, most effectively, the presence of active parasites. Polymerase chain reaction (PCR) can amplify and detect DNA from urine residue captured on Whatman No. 3 filter paper that is dried after filtration. Previously we have detected S. mansoni and S. haematobium parasite-specific small repeat DNA fragment from filtered urine on filter paper by PCR. In the current study, we assessed the efficacy of detection of 86 urine samples for either or both schistosome parasites by PCR and loop-mediated isothermal amplification (LAMP) that were collected from a low to moderate transmission area in Ghana. Two different DNA extraction methods, standard extraction kit and field usable LAMP-PURE kit were also evaluated by PCR and LAMP amplification. With S. haematobium LAMP amplification for both extractions showed similar sensitivity and specificity when compared with PCR amplification (100%) verified by gel electrophoresis. For S. mansoni sensitivity was highest for LAMP amplification (100%) for standard extraction than PCR and LAMP with LAMP-PURE (99% and 94%). The LAMP-PURE extraction produced false negatives, which require further investigation for this field usable extraction kit. Overall high positive and negative predictive values (90% - 100%) for both species demonstrated a highly robust approach. The LAMP approach is close to point of care use and equally sensitive and specific to detection of species-specific DNA by PCR. LAMP can be an effective means to detect low intensity infection due to its simplicity and minimal DNA extraction requirement. This will enhance the effectiveness of surveillance and MDA control programs of schistosomiasis. Copyright © 2017 Elsevier B.V. All rights reserved.

Estimating parasitic sea lamprey abundance in Lake Huron from heterogenous data sources

USGS Publications Warehouse

Young, Robert J.; Jones, Michael L.; Bence, James R.; McDonald, Rodney B.; Mullett, Katherine M.; Bergstedt, Roger A.

2003-01-01

The Great Lakes Fishery Commission uses time series of transformer, parasitic, and spawning population estimates to evaluate the effectiveness of its sea lamprey (Petromyzon marinus) control program. This study used an inverse variance weighting method to integrate Lake Huron sea lamprey population estimates derived from two estimation procedures: 1) prediction of the lake-wide spawning population from a regression model based on stream size and, 2) whole-lake mark and recapture estimates. In addition, we used a re-sampling procedure to evaluate the effect of trading off sampling effort between the regression and mark-recapture models. Population estimates derived from the regression model ranged from 132,000 to 377,000 while mark-recapture estimates of marked recently metamorphosed juveniles and parasitic sea lampreys ranged from 536,000 to 634,000 and 484,000 to 1,608,000, respectively. The precision of the estimates varied greatly among estimation procedures and years. The integrated estimate of the mark-recapture and spawner regression procedures ranged from 252,000 to 702,000 transformers. The re-sampling procedure indicated that the regression model is more sensitive to reduction in sampling effort than the mark-recapture model. Reliance on either the regression or mark-recapture model alone could produce misleading estimates of abundance of sea lampreys and the effect of the control program on sea lamprey abundance. These analyses indicate that the precision of the lakewide population estimate can be maximized by re-allocating sampling effort from marking sea lampreys to trapping additional streams.

21 CFR 520.1807 - Piperazine.

Code of Federal Regulations, 2011 CFR

2011-04-01

... control of parasitism. (2) Turkeys—(i) Amount. 100 milligrams per bird up to 12 weeks and 200 milligrams... veterinarian for assistance in the diagnosis, treatment, and control of parasitism. (3) Swine—(i) Amount. 50... control of parasitism. [64 FR 23018, Apr. 29, 1999] ...

Prevalence and co-infection of intestinal parasites among thai rural residents at high-risk of developing cholangiocarcinoma: a cross-sectional study in a prospective cohort study.

PubMed

Songserm, Nopparat; Promthet, Supannee; Wiangnon, Surapon; Sithithaworn, Paiboon

2012-01-01

Intestinal parasitic infections (IPIs) are still important to the health of Thai rural residents. IPIs are the cause of many chronic diseases with, for example, opisthorchiasis resulting in progression to cholangiocarcinoma (CCA). This cross-sectional study in a prospective cohort study aimed to examine the prevalence and co- infection of intestinal parasites among Northeastern Thai rural residents, recruited into the Khon Kaen Cohort Study (KKCS), and who were residing in areas of high-risk for developing CCA. On recruitment, subjects had completed questionnaires and provided fecal samples for IPI testing using the formalin ethyl acetate concentration technique. Data on selected general characteristics and the results of the fecal tests were analysed. IPI test results were available for 18,900 of cohort subjects, and 38.50% were found to be positive for one or more types of intestinal parasite. The prevalence of Opisthorchis viverrini (O. viverrini) infection was the highest (45.7%), followed by intestinal flukes (31.9%), intestinal nematodes (17.7%), intestinal protozoa (3.02%), and intestinal cestodes (1.69%). The pattern of different infections was similar in all age groups. According to a mapping analysis, a higher CCA burden was correlated with a higher prevalence of O. viverrini and intestinal flukes and a greater intensity of O. viverrini. Both prevention and control programs against liver fluke and other intestinal parasites are needed and should be delivered simultaneously. We can anticipate that the design of future control and prevention programmes will accommodate a more community-orientated and participatory approach.

Genetic analysis of resistance to ticks, gastrointestinal nematodes and Eimeria spp. in Nellore cattle.

PubMed

Passafaro, Tiago Luciano; Carrera, Juan Pablo Botero; dos Santos, Livia Loiola; Raidan, Fernanda Santos Silva; dos Santos, Dalinne Chrystian Carvalho; Cardoso, Eduardo Penteado; Leite, Romário Cerqueira; Toral, Fabio Luiz Buranelo

2015-06-15

The aim of the present study was to obtain genetic parameters for resistance to ticks, gastrointestinal nematodes (worms) and Eimeria spp. in Nellore cattle, analyze the inclusion of resistance traits in Nellore breeding programs and evaluate genetic selection as a complementary tool in parasite control programs. Counting of ticks, gastrointestinal nematode eggs and Eimeria spp. oocysts per gram of feces totaling 4270; 3872 and 3872 records from 1188; 1142 and 1142 animals, respectively, aged 146 to 597 days were used. The animals were classified as resistant (counts equal to zero) or susceptible (counts above zero) to each parasite. The statistical models included systematics effects of contemporary groups and the mean trajectory. The random effects included additive genetic effects, direct permanent environmental effects and residual. The mean trajectory and random effects were modeled with linear Legendre polynomials for all traits except for the mean trajectory of resistance to Eimeria spp., which employed the cubic polynomial. Heritability estimates were of low to moderate magnitude and ranged from 0.06 to 0.30, 0.06 to 0.33 and 0.04 to 0.33 for resistance to ticks, gastrointestinal nematodes and Eimeria spp., respectively. The posterior mean of genetic and environmental correlations for the same trait at different ages (205, 365, 450 and 550 days) were favorable at adjacent ages and unfavorable at distant ages. In general, the posterior mean of the genetic and environmental correlations between traits of resistance were low and high-density intervals were large and included zero in many cases. The heritability estimates support the inclusion of resistance to ticks, gastrointestinal nematodes and Eimeria spp. in Nellore breeding programs. Genetic selection can increase the frequency of resistant animals and be used as a complementary tool in parasite control programs. Copyright © 2015 Elsevier B.V. All rights reserved.

Population genetics, community of parasites, and resistance to rodenticides in an urban brown rat (Rattus norvegicus) population

PubMed Central

Gasqui, Patrick; Cosson, Jean-François; Benoît, Etienne; Lattard, Virginie; Crespin, Laurent; Lorvelec, Olivier; Pisanu, Benoît; Teynié, Alexandre; Vayssier-Taussat, Muriel; Bonnet, Sarah; Marianneau, Philippe; Lacôte, Sandra; Bourhy, Pascale; Berny, Philippe; Pavio, Nicole; Le Poder, Sophie; Gilot-Fromont, Emmanuelle; Jourdain, Elsa; Hammed, Abdessalem; Fourel, Isabelle; Chikh, Farid; Vourc’h, Gwenaël

2017-01-01

Brown rats are one of the most widespread urban species worldwide. Despite the nuisances they induce and their potential role as a zoonotic reservoir, knowledge on urban rat populations remains scarce. The main purpose of this study was to characterize an urban brown rat population from Chanteraines park (Hauts-de-Seine, France), with regards to haematology, population genetics, immunogenic diversity, resistance to anticoagulant rodenticides, and community of parasites. Haematological parameters were measured. Population genetics was investigated using 13 unlinked microsatellite loci. Immunogenic diversity was assessed for Mhc-Drb. Frequency of the Y139F mutation (conferring resistance to rodenticides) and two linked microsatellites were studied, concurrently with the presence of anticoagulant residues in the liver. Combination of microscopy and molecular methods were used to investigate the occurrence of 25 parasites. Statistical approaches were used to explore multiple parasite relationships and model parasite occurrence. Eighty-six rats were caught. The first haematological data for a wild urban R. norvegicus population was reported. Genetic results suggested high genetic diversity and connectivity between Chanteraines rats and surrounding population(s). We found a high prevalence (55.8%) of the mutation Y139F and presence of rodenticide residues in 47.7% of the sampled individuals. The parasite species richness was high (16). Seven potential zoonotic pathogens were identified, together with a surprisingly high diversity of Leptospira species (4). Chanteraines rat population is not closed, allowing gene flow and making eradication programs challenging, particularly because rodenticide resistance is highly prevalent. Parasitological results showed that co-infection is more a rule than an exception. Furthermore, the presence of several potential zoonotic pathogens, of which four Leptospira species, in this urban rat population raised its role in the maintenance and spread of these pathogens. Our findings should stimulate future discussions about the development of a long-term rat-control management program in Chanteraines urban park. PMID:28886097

Population genetics, community of parasites, and resistance to rodenticides in an urban brown rat (Rattus norvegicus) population.

PubMed

Desvars-Larrive, Amélie; Pascal, Michel; Gasqui, Patrick; Cosson, Jean-François; Benoît, Etienne; Lattard, Virginie; Crespin, Laurent; Lorvelec, Olivier; Pisanu, Benoît; Teynié, Alexandre; Vayssier-Taussat, Muriel; Bonnet, Sarah; Marianneau, Philippe; Lacôte, Sandra; Bourhy, Pascale; Berny, Philippe; Pavio, Nicole; Le Poder, Sophie; Gilot-Fromont, Emmanuelle; Jourdain, Elsa; Hammed, Abdessalem; Fourel, Isabelle; Chikh, Farid; Vourc'h, Gwenaël

2017-01-01

Brown rats are one of the most widespread urban species worldwide. Despite the nuisances they induce and their potential role as a zoonotic reservoir, knowledge on urban rat populations remains scarce. The main purpose of this study was to characterize an urban brown rat population from Chanteraines park (Hauts-de-Seine, France), with regards to haematology, population genetics, immunogenic diversity, resistance to anticoagulant rodenticides, and community of parasites. Haematological parameters were measured. Population genetics was investigated using 13 unlinked microsatellite loci. Immunogenic diversity was assessed for Mhc-Drb. Frequency of the Y139F mutation (conferring resistance to rodenticides) and two linked microsatellites were studied, concurrently with the presence of anticoagulant residues in the liver. Combination of microscopy and molecular methods were used to investigate the occurrence of 25 parasites. Statistical approaches were used to explore multiple parasite relationships and model parasite occurrence. Eighty-six rats were caught. The first haematological data for a wild urban R. norvegicus population was reported. Genetic results suggested high genetic diversity and connectivity between Chanteraines rats and surrounding population(s). We found a high prevalence (55.8%) of the mutation Y139F and presence of rodenticide residues in 47.7% of the sampled individuals. The parasite species richness was high (16). Seven potential zoonotic pathogens were identified, together with a surprisingly high diversity of Leptospira species (4). Chanteraines rat population is not closed, allowing gene flow and making eradication programs challenging, particularly because rodenticide resistance is highly prevalent. Parasitological results showed that co-infection is more a rule than an exception. Furthermore, the presence of several potential zoonotic pathogens, of which four Leptospira species, in this urban rat population raised its role in the maintenance and spread of these pathogens. Our findings should stimulate future discussions about the development of a long-term rat-control management program in Chanteraines urban park.

[A cross analysis on the capability of examining helminths: national technique competition for parasitic disease diagnosis in 2011].

PubMed

Zhang, Li; Li, Shi-Zhu; Li, Yu; Wang, Qiang; Fu, Qing; Liu, Wei; Zhu, Hong-Qing; Xu, Jing; Chen, Ying-Dan; Chen, Shao-Hong; Chen, Jia-Xu; Chen, Zhao; Wang, Li-Ying; Zhou, Xiao-Nong

2012-08-30

To understand the comprehensive capability of helminth detection among professionals at different level of parasitic disease control institutions and promote the overall strength of diagnosis. Four professionals from each parasitic diseases control institutions were selected as contestant (age < 45 and at least two contestant from county-level institution). The content of contest included making stool slides with Kato-Katz method (five slides in thirty minutes, a total score of 15 and 9 as passing score) and identification of eleven common helminth eggs with microscopy (ten slides, five minutes per slide, a total score of 60, 36 as passing score). The average score of making slides in 119 contestants from 30 provinces was 11.4, and 119 contestants passed accounted for 93.3%. The average score of film-reading was 22.0, and 20 contestants passed accounted for 16.8%. There were no statistically significant differences between the results in different gender, age (< or = 30, 31-40, > 40), job title (the junior, intermediate, and senior), institution level (provincial, municipal, and county level) (P > 0.05). By Kato-Katz slide-making and film-reading, the scores in contestants from provinces with schistosomiasis control task (12.1 +/- 1.7, 32.1 +/- 11.5, respectively) were better than contestants from other provinces (11.1 +/- 1.8, 18.1 +/- 10.5, respectively). The scores in contestants from western (18.4 +/- 11.4) were lower than those from eastern (25.2 +/- 12.4) and central (24.1 +/- 13.1) for film-reading. The overall capability of parasitic disease examination is unbalanced among regions, and evidently there is a need to strengthen the capacity of pathogen detection in the disease control programs.

Global change, parasite transmission and disease control: lessons from ecology

PubMed Central

Boag, Brian; Ellison, Amy R.; Morgan, Eric R.; Murray, Kris; Pascoe, Emily L.; Sait, Steven M.; Booth, Mark

2017-01-01

Parasitic infections are ubiquitous in wildlife, livestock and human populations, and healthy ecosystems are often parasite rich. Yet, their negative impacts can be extreme. Understanding how both anticipated and cryptic changes in a system might affect parasite transmission at an individual, local and global level is critical for sustainable control in humans and livestock. Here we highlight and synthesize evidence regarding potential effects of ‘system changes’ (both climatic and anthropogenic) on parasite transmission from wild host–parasite systems. Such information could inform more efficient and sustainable parasite control programmes in domestic animals or humans. Many examples from diverse terrestrial and aquatic natural systems show how abiotic and biotic factors affected by system changes can interact additively, multiplicatively or antagonistically to influence parasite transmission, including through altered habitat structure, biodiversity, host demographics and evolution. Despite this, few studies of managed systems explicitly consider these higher-order interactions, or the subsequent effects of parasite evolution, which can conceal or exaggerate measured impacts of control actions. We call for a more integrated approach to investigating transmission dynamics, which recognizes these complexities and makes use of new technologies for data capture and monitoring, and to support robust predictions of altered parasite dynamics in a rapidly changing world. This article is part of the themed issue ‘Opening the black box: re-examining the ecology and evolution of parasite transmission’. PMID:28289256

Molecular epidemiology of bovine Babesia spp. and Theileria orientalis parasites in beef cattle from northern and northeastern Thailand.

PubMed

Jirapattharasate, Charoonluk; Adjou Moumouni, Paul Franck; Cao, Shinuo; Iguchi, Aiko; Liu, Mingming; Wang, Guanbo; Zhou, Mo; Vudriko, Patrick; Changbunjong, Tanasak; Sungpradit, Sivapong; Ratanakorn, Parntep; Moonarmart, Walasinee; Sedwisai, Poonyapat; Weluwanarak, Thekhawet; Wongsawang, Witsanu; Suzuki, Hiroshi; Xuan, Xuenan

2016-02-01

Beef cattle production represents the largest cattle population in Thailand. Their productivity is constrained by tick-borne diseases such as babesiosis and theileriosis. In this study, we determined the prevalence of Babesia bigemina, Babesia bovis and Theileria orientalis using polymerase chain reaction (PCR). The genetic markers that were used for detection of the above parasites were sequenced to determine identities and similarity for Babesia spp. and genetic diversity of T. orientalis. Furthermore the risk factors for the occurrence of the above protozoan parasites in beef cattle from northern and northeastern parts of Thailand were assessed. A total of 329 blood samples were collected from beef cattle in 6 provinces. The study revealed that T. orientalis was the most prevalent (30.1%) parasite in beef cattle followed by B. bigemina (13.1%) and B. bovis (5.5%). Overall, 78.7% of the cattle screened were infected with at least one of the above parasites. Co-infection with Babesia spp. and T. orientalis was 30.1%. B. bigemina and T. orientalis were the most prevalent (15.1%) co-infection although triple infection with the three parasites was observed in 3.0% of the samples. Sequencing analysis revealed that B. bigemina RAP1 gene and B. bovis SBP2 gene were conserved among the parasites from different cattle samples. Phylogenetic analysis showed that the T. orientalis MPSP gene from parasites isolated from cattle in north and northeast Thailand was classified into types 5 and 7 as reported previously. Lack of tick control program was the universal risk factor of the occurrence of Babesia spp. and T. orientalis infection in beef cattle in northern and northeastern Thailand. We therefore recommend training of farmers on appropriate tick control strategies and further research on potential vectors for T. orientalis and elucidate the effect of co-infection with Babesia spp. on the pathogenicity of T. orientalis infection on beef in northern and northeastern Thailand. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

42 CFR 493.917 - Parasitology.

Code of Federal Regulations, 2011 CFR

2011-10-01

... purposes— (1) Those that determine the presence or absence of parasites by direct observation (wet mount... certified in the subspecialty of parasitology for identification; (2) Those that identify parasites using... designee for on-site testing. An annual program must include samples that contain parasites that are...

Radiographing puparia of tachinid parasites of the gypsy moth, and application in parasite-release programs

Treesearch

T. M. Odell; P. A. Godwin; W. B. White

1974-01-01

A radiographic technique has been developed for observing and quantifying development and mortality of Blepharipa scutellata ( Robineau-Desvoidy), Parasetigena agilis (Robineau-Desvoidy), and Compsilura concinnata (Meigen), tachinid parasites of the gypsy moth, Porthetria dispar (L.). Puparia...

Dual RNA-seq reveals no plastic transcriptional response of the coccidian parasite Eimeria falciformis to host immune defenses.

PubMed

Ehret, Totta; Spork, Simone; Dieterich, Christoph; Lucius, Richard; Heitlinger, Emanuel

2017-09-05

Parasites can either respond to differences in immune defenses that exist between individual hosts plastically or, alternatively, follow a genetically canalized ("hard wired") program of infection. Assuming that large-scale functional plasticity would be discernible in the parasite transcriptome we have performed a dual RNA-seq study of the lifecycle of Eimeria falciformis using infected mice with different immune status as models for coccidian infections. We compared parasite and host transcriptomes (dual transcriptome) between naïve and challenge infected mice, as well as between immune competent and immune deficient ones. Mice with different immune competence show transcriptional differences as well as differences in parasite reproduction (oocyst shedding). Broad gene categories represented by differently abundant host genes indicate enrichments for immune reaction and tissue repair functions. More specifically, TGF-beta, EGF, TNF and IL-1 and IL-6 are examples of functional annotations represented differently depending on host immune status. Much in contrast, parasite transcriptomes were neither different between Coccidia isolated from immune competent and immune deficient mice, nor between those harvested from naïve and challenge infected mice. Instead, parasite transcriptomes have distinct profiles early and late in infection, characterized largely by biosynthesis or motility associated functional gene groups, respectively. Extracellular sporozoite and oocyst stages showed distinct transcriptional profiles and sporozoite transcriptomes were found enriched for species specific genes and likely pathogenicity factors. We propose that the niche and host-specific parasite E. falciformis uses a genetically canalized program of infection. This program is likely fixed in an evolutionary process rather than employing phenotypic plasticity to interact with its host. This in turn might limit the potential of the parasite to adapt to new host species or niches, forcing it to coevolve with its host.

Ivermectin: a complimentary weapon against the spread of malaria?

PubMed Central

Alout, Haoues; Foy, Brian

2017-01-01

Introduction Ivermectin has transformed the treatment of parasitic diseases and led to incommensurable benefits to humans and animals. Ivermectin is effective in treating several neglected infectious diseases and recently it has been shown to reduce malaria parasite transmission. Areas covered Malaria control strategies could benefit from the addition of ivermectin to interrupt the transmission cycle if it is a long lasting formulation or repeatedly administered. In turn, this will help also to control neglected infectious diseases where the elimination goal has been slower to achieve. Despite the relevance of using ivermectin for integrated and sustained disease control, there are still essential questions that remain to be addressed about safety and practicality. The efficacy in various malaria ecologies and the interaction between control tools, either drugs or insecticides, are also important to assess. Expert commentary Overlapping distribution of several infectious diseases reveals the benefit of integrating control programs against several infectious diseases into one strategy for cost effectiveness and to reach the elimination goals. The use of ivermectin to control malaria transmission will necessitate development and testing of long-lasting formulations or repeated treatments, and implementation of these treatments with other disease control tools may increase the chance of successful and sustained control. PMID:27960597

Exploring the host transcriptome for mechanisms underlying protective immunity and resistance to nematode infections in ruminants.

PubMed

Li, Robert W; Choudhary, Ratan K; Capuco, Anthony V; Urban, Joseph F

2012-11-23

Nematode infections in ruminants are a major impediment to the profitable production of meat and dairy products, especially for small farms. Gastrointestinal parasitism not only negatively impacts weight gain and milk yield, but is also a major cause of mortality in small ruminants. The current parasite control strategy involves heavy use of anthelmintics that has resulted in the emergence of drug-resistant parasite strains. This, in addition to increasing consumer demand for animal products that are free of drug residues has stimulated development of alternative strategies, including selective breeding of parasite resistant ruminants. The development of protective immunity and manifestations of resistance to nematode infections relies upon the precise expression of the host genome that is often confounded by mechanisms simultaneously required to control multiple nematode species as well as ecto- and protozoan parasites, and microbial and viral pathogens. Understanding the molecular mechanisms underlying these processes represents a key step toward development of effective new parasite control strategies. Recent progress in characterizing the transcriptome of both hosts and parasites, utilizing high-throughput microarrays and RNA-seq technology, has led to the recognition of unique interactions and the identification of genes and biological pathways involved in the response to parasitism. Innovative use of the knowledge gained by these technologies should provide a basis for enhancing innate immunity while limiting the polarization of acquired immunity can negatively affect optimal responses to co-infection. Strategies for parasite control that use diet and vaccine/adjuvant combination could be evaluated by monitoring the host transcriptome for induction of appropriate mechanisms for imparting parasite resistance. Knowledge of different mechanisms of host immunity and the critical regulation of parasite development, physiology, and virulence can also selectively identify targets for parasite control. Comparative transcriptome analysis, in concert with genome-wide association (GWS) studies to identify quantitative trait loci (QTLs) affecting host resistance, represents a promising molecular technology to evaluate integrated control strategies that involve breed and environmental factors that contribute to parasite resistance and improved performance. Tailoring these factors to control parasitism without severely affecting production qualities, management efficiencies, and responses to pathogenic co-infection will remain a challenge. This review summarizes recent progress and limitations of understanding regulatory genetic networks and biological pathways that affect host resistance and susceptibility to nematode infection in ruminants. Published by Elsevier B.V.

Parasite control in the age of drug resistance and changing agricultural practices.

PubMed

Molento, Marcelo Beltrão

2009-08-07

The benefits of using antiparasitic drugs in farm animals are unquestionable. However, despite anthelmintic use as the predominant control strategy, extreme parasite infection cases are appearing in sheep and goat production; these impact productivity and have show mortality rates reaching pre-drug use levels. This was a predictable situation resulting from the loss of efficacy by all available products, particularly when some products were used as the sole intervention. The concepts of agroecology and holistic agriculture, which advocate the use of integrated management strategies, such as target selected treatment, herbal medicine, and the application of other parasite control alternatives, are not completely new, but are undergoing a resurgence because of their more sustainable appeal. The objective of this review article is to examine the problem of parasite control in the face of parasite drug resistance and to outline some strategies that may be used in parasite control programmes. Before they are accepted and recommended by the WAAVP, agroecological methods such as those listed above and described in detail herein should be validated based on scientific evidence of their efficacy for parasite control and should be tested for both host and environmental safety.

Significance of Plankton Community Structure and Nutrient Availability for the Control of Dinoflagellate Blooms by Parasites: A Modeling Approach

PubMed Central

Alves-de-Souza, Catharina; Pecqueur, David; Le Floc’h, Emilie; Mas, Sébastien; Roques, Cécile; Mostajir, Behzad; Vidussi, Franscesca; Velo-Suárez, Lourdes; Sourisseau, Marc; Fouilland, Eric; Guillou, Laure

2015-01-01

Dinoflagellate blooms are frequently observed under temporary eutrophication of coastal waters after heavy rains. Growth of these opportunistic microalgae is believed to be promoted by sudden input of nutrients and the absence or inefficiency of their natural enemies, such as grazers and parasites. Here, numerical simulations indicate that increasing nutrient availability not only promotes the formation of dinoflagellate blooms but can also stimulate their control by protozoan parasites. Moreover, high abundance of phytoplankton other than dinoflagellate hosts might have a significant dilution effect on the control of dinoflagellate blooms by parasites, either by resource competition with dinoflagellates (thus limiting the number of hosts available for infection) or by affecting numerical-functional responses of grazers that consume free-living parasite stages. These outcomes indicate that although both dinoflagellates and their protozoan parasites are directly affected by nutrient availability, the efficacy of the parasitic control of dinoflagellate blooms under temporary eutrophication depends strongly on the structure of the plankton community as a whole. PMID:26030411

Comparative anatomy and histology of developmental and parasitic stages in the life cycle of the lined sea anemone Edwardsiella lineata.

PubMed

Reitzel, Adam M; Daly, Marymegan; Sullivan, James C; Finnerty, John R

2009-02-01

The evolution of parasitism is often accompanied by profound changes to the developmental program. However, relatively few studies have directly examined the developmental evolution of parasitic species from free-living ancestors. The lined sea anemone Edwardsiella lineata is a relatively recently evolved parasite for which closely related free-living outgroups are known, including the starlet sea anemone Nematostella vectensis. The larva of E. lineata parasitizes the ctenophore Mnemiopsis leidyi, and, once embedded in its host, the anemone assumes a novel vermiform body plan. That we might begin to understand how the developmental program of this species has been transformed during the evolution of parasitism, we characterized the gross anatomy, histology, and cnidom of the parasitic stage, post-parasitic larval stage, and adult stage of the E. lineata life cycle. The distinct parasitic stage of the life cycle differs from the post-parasitic larva with respect to overall shape, external ciliation, cnida frequency, and tissue architecture. The parasitic stage and planula both contain holotrichs, a type of cnida not previously reported in Edwardsiidae. The internal morphology of the post-parasitic planula is extremely similar to the adult morphology, with a complete set of mesenterial tissue and musculature despite this stage having little external differentiation. Finally, we observed 2 previously undocumented aspects of asexual reproduction in E. lineata: (1) the parasitic stage undergoes transverse fission via physal pinching, the first report of asexual reproduction in a pre-adult stage in the Edwardsiidae; and (2) the juvenile polyp undergoes transverse fission via polarity reversal, the first time this form of fission has been reported in E. lineata.

25 CFR 168.15 - Control of livestock diseases and parasites.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 25 Indians 1 2010-04-01 2010-04-01 false Control of livestock diseases and parasites. 168.15... REGULATIONS FOR THE HOPI PARTITIONED LANDS AREA § 168.15 Control of livestock diseases and parasites. Whenever livestock within the Hopi Partitioned Lands become infected with contagious or infectious diseases or...

25 CFR 168.15 - Control of livestock diseases and parasites.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 25 Indians 1 2011-04-01 2011-04-01 false Control of livestock diseases and parasites. 168.15... REGULATIONS FOR THE HOPI PARTITIONED LANDS AREA § 168.15 Control of livestock diseases and parasites. Whenever livestock within the Hopi Partitioned Lands become infected with contagious or infectious diseases or...

25 CFR 168.15 - Control of livestock diseases and parasites.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 25 Indians 1 2014-04-01 2014-04-01 false Control of livestock diseases and parasites. 168.15... REGULATIONS FOR THE HOPI PARTITIONED LANDS AREA § 168.15 Control of livestock diseases and parasites. Whenever livestock within the Hopi Partitioned Lands become infected with contagious or infectious diseases or...

25 CFR 168.15 - Control of livestock diseases and parasites.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 25 Indians 1 2012-04-01 2011-04-01 true Control of livestock diseases and parasites. 168.15... REGULATIONS FOR THE HOPI PARTITIONED LANDS AREA § 168.15 Control of livestock diseases and parasites. Whenever livestock within the Hopi Partitioned Lands become infected with contagious or infectious diseases or...

25 CFR 168.15 - Control of livestock diseases and parasites.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 25 Indians 1 2013-04-01 2013-04-01 false Control of livestock diseases and parasites. 168.15... REGULATIONS FOR THE HOPI PARTITIONED LANDS AREA § 168.15 Control of livestock diseases and parasites. Whenever livestock within the Hopi Partitioned Lands become infected with contagious or infectious diseases or...

[Study on a new prevention and control model on soil-borne parasitic diseases in rural areas of China].

PubMed

Li, Xue-Ming; Chen, Ying-Dan; Xu, Long-Qi; Zhou, Chang-Hai; Ou-Yang, Yi; Lin, Rui; Yang, Fang-Fang; Zhang, Xiao-Juan; Wang, Ge; Liu, Teng; Wang, Jing

2011-12-01

To explore a new prevention and control model on soil-borne parasitic diseases in rural areas of China. Eight provinces and autonomous regions were selected in China as demonstration areas implementing integrated control on soil-borne parasitic diseases. The integrated control measures included authority organization and harmonization, health education, deworming, and environment modification. After three years, the infection rates of soil-borne parasitic diseases were significantly decreased in these areas. There were three safe guard and organization modes, three health education modes, four mass worming medication modes, and two modes of water, toilet and environment changes. The work in the various demonstration areas was summarized which pointed out a new model with efficiency and local characteristics on soil-borne parasitic disease prevention and control.

Development of a health education intervention strategy using an implementation research method to control taeniasis and cysticercosis in Burkina Faso.

PubMed

Ngowi, Helena; Ozbolt, Ivan; Millogo, Athanase; Dermauw, Veronique; Somé, Télesphore; Spicer, Paul; Jervis, Lori L; Ganaba, Rasmané; Gabriel, Sarah; Dorny, Pierre; Carabin, Hélène

2017-06-01

Taeniasis and cysticercosis are two diseases caused by Taenia solium, a parasite transmitted between humans and pigs, leading to considerable economic loss and disabilities. Transmission of the parasite is linked to environmental and behavioural factors such as inadequate sanitation and hygiene, poor pig management, and consumption of infected pork. This study used implementation research method to design a health education intervention strategy for reducing T. solium infections in Burkina Faso, a country endemic for the parasite. Eighteen group discussions were conducted with 8-18 participants each in three villages. In addition, structured interviews were conducted among 4 777 participants and 2 244 pig owners, who were selected through cluster random sampling in 60 villages of three provinces of Burkina Faso. Both approaches assessed knowledge and practices related to T. solium. The information obtained was used to develop a community-adapted health education intervention strategy to control taeniasis and cysticercosis in Burkina Faso. The group discussions revealed that participants had a poor quality of life due to the diseases as well as inadequate access to latrines, safe water, and healthcare services. In addition, it was found that pig production was an important economic activity, especially for women. Furthermore, financial and knowledge constraints were important limitations to improved pig management and latrine construction. The survey data also showed that open defecation and drinking unboiled water were common behaviours, enhanced by a lack of knowledge regarding the transmission of the parasite, perceived financial barriers to the implementation of control measures, lack of public sensitization, as well as a lack of self-efficacy towards control of the parasite. Nevertheless, the perceived financial benefits of controlling porcine cysticercosis could be emphasized by an education program that discourages open defecation and encourages drinking safe water. The final intervention strategy included a Participatory Hygiene and Sanitation Transformation (PHAST) approach, as well as a 52-min film and an accompanying comic booklet. The main problem in the study communities regarding the transmission of T. solium cysticercosis is the random disposal of human faeces, which can be contaminated with parasite eggs. Prevention of open defecation requires the building of latrines, which can be quite problematic in economically challenged settings. Providing the community with the skills to construct durable latrines using low-cost locally available materials would likely help to resolve this problem. Further studies are required to implement and evaluate the T. solium control strategy developed in this study.

Fecal parasite identification by microscopy and PCR in scimitar-horned oryx, Oryx dammah, managed at two sites.

PubMed

Pauling, Cassandra Dawn; Oller, Anna R; Jackson, Victoria

2016-12-01

The scimitar-horned oryx, Oryx dammah , an endangered species extinct in the wild, is managed in various captive management programs and is the focus of reintroduction efforts. Management variability can contribute to substantial parasite load differences, which can affect deworming programs and potentially transfer parasites to different regions with translocations. Parasite studies in O. dammah are lacking. In this study, we determined fecal egg/oocyst counts of O. dammah in two captive herds, Fossil Rim Wildlife Center (FRWC) and Kansas City Zoo (KCZ). Fecal egg counts (FEC) were performed on O. dammah feces collected seasonally using the modified McMaster method, and microscopy provided additional identification of parasite genera ova and oocysts. To identify parasites to species level, homogenized fecals provided DNA subjected to the polymerase chain reaction (PCR) using genus specific primers. Microscopy and sequencing results indicated the presence of Strongylus (Strongylus vulgaris, Angiostrongylus cantonensis) , Trichostrongylus (Haemonchus contortus, Camelostrongylus mentulatus) , Trichuris (T. leporis, T. ovis, and T. discolor) , Isospora (Isospora gryphoni) and Eimeria (E. zuernii and E. bovis) , with Strongylus being the most common. Nematodirus was identified through microscopy at FRWC. Fecal egg counts were significantly higher in (FRWC) than in (KCZ) in all samplings (P = <0.001). No significant difference was seen between parasite load and seasons (P = 0.103), nor site and season (P = 0.51). Both study sites maintained most animals within commonly accepted FEC levels found in domestic livestock. Individuals with high numbers of EPG or OPG were subordinate males, pregnant females, or neonates. Several significant interactions were found between genera of parasites, age, sex, season, and pregnancy status in the FRWC herd. Sampling limitations prevented further analysis of the KCZ herd. Understanding interactions between parasite loads and physiological, environmental, and regional differences can help determine inter-specific transfer of parasites, and establish appropriate anthelmintic programs for O. dammah herds.

[Molecular characterization of Echinococcus granulosus isolates obtained from different hosts].

PubMed

Erdoğan, Emrah; Özkan, Bora; Mutlu, Fatih; Karaca, Serkan; Şahin, İzzet

2017-01-01

Echinococcus granulosus is a parasite that can be seen throughout the world. So far, five species of genus Echinococcus have been identified as parasite in people: E.granulosus, E.multilocularis, E.vogeli, E.oligarthrus, E.shiquicus. Larval (metacestod) form of parasite settles in internal organs of hoofed animals (cattle, goats, pigs, horses, sheep, etc.) and human; the adult form is found in small intestine of final host, canine. Disease caused by parasite called as "Cystic echinococcosis" (CE) is an important health problem and causes economic losses in many countries including our country that livestock is common. Infective eggs cause infections in intermediate hosts by taking oral way and rarely inhalation. Received egg opens in the stomach and intestines of intermediate host and oncosphere is released. Oncosphere quickly reaches the lamina propria of the villus epithelium by its histolytic enzymes and hooks. It usually transported from here to the liver and lungs, less frequently, muscle, brain, spleen, kidney and to other organs through the veins. By molecular studies, five species have been validated taxonomically and 10 different variants or strains of E.granulosus have been identified. Host and developmental differences between strains may negatively affect control studies and fight against the parasite. This study aimed to determinate E.granulosus strains obtained from cyst material of different intermediate hosts from different regions of Turkey by molecular methods. In the study, 25 human, 8 cattle, 6 sheep and 2 goat cysts material has been collected. Total genomic DNA was isolated from protoscoleces in cyst fluid and analyzed by PCR with COX-1 (L) and COX-1 (S) genes specific primers. DNA sequence analysis for each PCR product has been made. DNA sequence analysis results evaluated phylogenetically by MEGA analyze and BLAST software. As a result of this study, all isolates were identified as E.granulosus sensu stricto (G1) by DNA sequence analysis. CE is a major public health problem for our country so we believe that obtained data from this study is an important source for parasite control, effective diagnosis, treatment techniques, eradication, vaccination and drug development. Similar studies will be beneficial to cover all other regions of Turkey and to develop effective and successful control programs.

Ecotope-Based Entomological Surveillance and Molecular Xenomonitoring of Multidrug Resistant Malaria Parasites in Anopheles Vectors

PubMed Central

2014-01-01

The emergence and spread of multidrug resistant (MDR) malaria caused by Plasmodium falciparum or Plasmodium vivax have become increasingly important in the Greater Mekong Subregion (GMS). MDR malaria is the heritable and hypermutable property of human malarial parasite populations that can decrease in vitro and in vivo susceptibility to proven antimalarial drugs as they exhibit dose-dependent drug resistance and delayed parasite clearance time in treated patients. MDR malaria risk situations reflect consequences of the national policy and strategy as this influences the ongoing national-level or subnational-level implementation of malaria control strategies in endemic GMS countries. Based on our experience along with current literature review, the design of ecotope-based entomological surveillance (EES) and molecular xenomonitoring of MDR falciparum and vivax malaria parasites in Anopheles vectors is proposed to monitor infection pockets in transmission control areas of forest and forest fringe-related malaria, so as to bridge malaria landscape ecology (ecotope and ecotone) and epidemiology. Malaria ecotope and ecotone are confined to a malaria transmission area geographically associated with the infestation of Anopheles vectors and particular environments to which human activities are related. This enables the EES to encompass mosquito collection and identification, salivary gland DNA extraction, Plasmodium- and species-specific identification, molecular marker-based PCR detection methods for putative drug resistance genes, and data management. The EES establishes strong evidence of Anopheles vectors carrying MDR P. vivax in infection pockets epidemiologically linked with other data obtained during which a course of follow-up treatment of the notified P. vivax patients receiving the first-line treatment was conducted. For regional and global perspectives, the EES would augment the epidemiological surveillance and monitoring of MDR falciparum and vivax malaria parasites in hotspots or suspected areas established in most endemic GMS countries implementing the National Malaria Control Programs, in addition to what is guided by the World Health Organization. PMID:25349605

Emission and soil distribution of fumigants in forest tree nurseries

Treesearch

Dong Wang; Jennifer Juzwik; Stephen Fraedrich

2005-01-01

Production of tree seedlings in the majority of forest nurseries in the USA has relied on soil fumigation with methyl bromide (MeBr) to control soil-borne plant pathogens, weeds, parasitic nematodes and insects. Since the announcement of the scheduled MeBr phase-out, a number of nurseries throughout the United States have participated in research programs on MeBr...

Possible application of a nematophagous fungus as a biological control agent of parasitic nematodes on commercial sheep farms in South Africa.

PubMed

Faedo, M; Krecek, R C

2002-03-01

Biological control of parasitic nematodes of livestock is currently under development and represents another tool that may be integrated into helminth parasite control strategies. This paper presents a brief introduction to commercial sheep farming in South Africa and currently available nematode parasite control methods. These include the FAMACHA clinical assay, strategies of pasture management, dilution of resistant worm species by introduction of susceptible worms, breed resistant sheep and nutritional supplementation. The purpose of this paper is to outline the principles of biological control using nematophagous fungi and how it may be applied on sheep farms in South Africa.

Predation on transmission stages reduces parasitism: sea anemones consume transmission stages of a barnacle parasite.

PubMed

Fong, Caitlin R; Kuris, Armand M

2017-06-01

While parasites serve as prey, it is unclear how the spatial distribution of parasite predators provides transmission control and influences patterns of parasitism. Because many of its organisms are sessile, the rocky intertidal zone is a valuable but little used system to understand spatial patterns of parasitism and elucidate the underlying mechanisms driving these patterns. Sea anemones and barnacles are important space competitors in the rocky intertidal zone along the Pacific coast of North America. Anemones are voracious, indiscriminate predators; thus, they may intercept infectious stages of parasites before they reach a host. We investigate whether a sea anemone protects an associated barnacle from parasitism by Hemioniscus balani, an isopod parasitic castrator. At Coal Oil Point, Santa Barbara, California USA, 29% of barnacles were within 1 cm from an anemone at the surveyed tidal height. Barnacles associated with anemones had reduced parasite prevalence and higher reproductive productivity than those remote from sea anemones. In the laboratory, anemones readily consumed the transmission stage of the parasite. Hence, anemone consumption of parasite transmission stages may provide a mechanism by which community context regulates parasite prevalence at a local scale. Our results suggest predation may be an important process providing parasite transmission control.

The Diagnosis of Human Fascioliasis by Enzyme-Linked Immunosorbent Assay (ELISA) Using Recombinant Cathepsin L Protease

PubMed Central

Gonzales Santana, Bibiana; Vasquez Camargo, Fabio; Parkinson, Michael

2013-01-01

Background Fascioliasis is a worldwide parasitic disease of domestic animals caused by helminths of the genus Fasciola. In many parts of the world, particularly in poor rural areas where animal disease is endemic, the parasite also infects humans. Adult parasites reside in the bile ducts of the host and therefore diagnosis of human fascioliasis is usually achieved by coprological examinations that search for parasite eggs that are carried into the intestine with the bile juices. However, these methods are insensitive due to the fact that eggs are released sporadically and may be missed in low-level infections, and fasciola eggs may be misclassified as other parasites, leading to problems with specificity. Furthermore, acute clinical symptoms as a result of parasites migrating to the bile ducts appear before the parasite matures and begins egg laying. A human immune response to Fasciola antigens occurs early in infection. Therefore, an immunological method such as ELISA may be a more reliable, easy and cheap means to diagnose human fascioliasis than coprological analysis. Methodology/Principal findings Using a panel of serum from Fasciola hepatica-infected patients and from uninfected controls we have optimized an enzyme-linked immunosorbent assay (ELISA) which employs a recombinant form of the major F. hepatica cathepsin L1 as the antigen for the diagnosis of human fascioliasis. We examined the ability of the ELISA test to discern fascioliasis from various other helminth and non-helminth parasitic diseases. Conclusions/Significance A sensitive and specific fascioliasis ELISA test has been developed. This test is rapid and easy to use and can discriminate fasciola-infected individuals from patients harbouring other parasites with at least 99.9% sensitivity and 99.9% specificity. This test will be a useful standardized method not only for testing individual samples but also in mass screening programs to assess the extent of human fascioliasis in regions where this zoonosis is suspected. PMID:24069474

The diagnosis of human fascioliasis by enzyme-linked immunosorbent assay (ELISA) using recombinant cathepsin L protease.

PubMed

Gonzales Santana, Bibiana; Dalton, John P; Vasquez Camargo, Fabio; Parkinson, Michael; Ndao, Momar

2013-01-01

Fascioliasis is a worldwide parasitic disease of domestic animals caused by helminths of the genus Fasciola. In many parts of the world, particularly in poor rural areas where animal disease is endemic, the parasite also infects humans. Adult parasites reside in the bile ducts of the host and therefore diagnosis of human fascioliasis is usually achieved by coprological examinations that search for parasite eggs that are carried into the intestine with the bile juices. However, these methods are insensitive due to the fact that eggs are released sporadically and may be missed in low-level infections, and fasciola eggs may be misclassified as other parasites, leading to problems with specificity. Furthermore, acute clinical symptoms as a result of parasites migrating to the bile ducts appear before the parasite matures and begins egg laying. A human immune response to Fasciola antigens occurs early in infection. Therefore, an immunological method such as ELISA may be a more reliable, easy and cheap means to diagnose human fascioliasis than coprological analysis. Using a panel of serum from Fasciola hepatica-infected patients and from uninfected controls we have optimized an enzyme-linked immunosorbent assay (ELISA) which employs a recombinant form of the major F. hepatica cathepsin L1 as the antigen for the diagnosis of human fascioliasis. We examined the ability of the ELISA test to discern fascioliasis from various other helminth and non-helminth parasitic diseases. A sensitive and specific fascioliasis ELISA test has been developed. This test is rapid and easy to use and can discriminate fasciola-infected individuals from patients harbouring other parasites with at least 99.9% sensitivity and 99.9% specificity. This test will be a useful standardized method not only for testing individual samples but also in mass screening programs to assess the extent of human fascioliasis in regions where this zoonosis is suspected.

Between a bug and a hard place: Trypanosoma cruzi genetic diversity and the clinical outcomes of Chagas disease

PubMed Central

Messenger, Louisa A; Miles, Michael A; Bern, Caryn

2015-01-01

Over the last 30 years, concomitant with successful transnational disease control programs across Latin America, Chagas disease has expanded from a neglected, endemic parasitic infection of the rural poor to an urbanized chronic disease, and now a potentially emergent global health problem. Trypanosoma cruzi infection has a highly variable clinical course, ranging from complete absence of symptoms to severe and often fatal cardiovascular and/or gastrointestinal manifestations. To date, few correlates of clinical disease progression have been identified. Elucidating a putative role for T. cruzi strain diversity in Chagas disease pathogenesis is complicated by the scarcity of parasites in clinical specimens and the limitations of our contemporary genotyping techniques. This article systematically reviews the historical literature, given our current understanding of parasite genetic diversity, to evaluate the evidence for any association between T. cruzi genotype and chronic clinical outcome, risk of congenital transmission or reactivation and orally transmitted outbreaks. PMID:26162928

Towards the Development of THz-Sensors for the Detection of African Trypanosomes

NASA Astrophysics Data System (ADS)

Knieß, Robert; Wagner, Carolin B.; Ulrich Göringer, H.; Mueh, Mario; Damm, Christian; Sawallich, Simon; Chmielak, Bartos; Plachetka, Ulrich; Lemme, Max

2018-03-01

Human African trypanosomiasis (HAT) is a neglected tropical disease (NTD) for which adequate therapeutic and diagnostic measures are still lacking. Causative agent of HAT is the African trypanosome, a single-cell parasite, which propagates in the blood and cerebrospinal fluid of infected patients. Although different testing methods for the pathogen exist, none is robust, reliable and cost-efficient enough to support large-scale screening and control programs. Here we propose the design of a new sensor-type for the detection of infective-stage trypanosomes. The sensor exploits the highly selective binding capacity of nucleic acid aptamers to the surface of the parasite in combination with passive sensor structures to allow an electromagnetic remote read-out using terahertz (THz)-radiation. The short wavelength provides a superior interaction with the parasite cells than longer wavelengths, which is essential for a high sensitivity. We present two different sensor structures using both, micro- and nano-scale elements, as well as different measurement principles.

Beneficial Insect Attraction to Milkweeds (Asclepias speciosa, Asclepias fascicularis) in Washington State, USA

PubMed Central

James, David G.; Seymour, Lorraine; Lauby, Gerry; Buckley, Katie

2016-01-01

Native plant and beneficial insect associations are relatively unstudied yet are important in native habitat restoration programs for improving and sustaining conservation biological control of arthropod pests in agricultural crops. Milkweeds (Asclepias spp.) are currently the focus of restoration programs in the USA aimed at reversing a decline in populations of the milkweed-dependent monarch butterfly (Danaus plexippus); however, little is known of the benefits of these plants to other beneficial insects. Beneficial insects (predators, parasitoids, pollinators) attracted to two milkweed species (Asclepias speciosa, Asclepias fascicularis) in central Washington State, WA, USA were identified and counted on transparent sticky traps attached to blooms over five seasons. Combining all categories of beneficial insects, means of 128 and 126 insects per trap were recorded for A. speciosa and A. fascicularis, respectively. Predatory and parasitic flies dominated trap catches for A. speciosa while parasitic wasps were the most commonly trapped beneficial insects on A. fascicularis. Bees were trapped commonly on both species, especially A. speciosa with native bees trapped in significantly greater numbers than honey bees. Beneficial insect attraction to A. speciosa and A. fascicularis was substantial. Therefore, these plants are ideal candidates for habitat restoration, intended to enhance conservation biological control, and for pollinator conservation. In central Washington, milkweed restoration programs for enhancement of D. plexippus populations should also provide benefits for pest suppression and pollinator conservation. PMID:27367733

Beneficial Insect Attraction to Milkweeds (Asclepias speciosa, Asclepias fascicularis) in Washington State, USA.

PubMed

James, David G; Seymour, Lorraine; Lauby, Gerry; Buckley, Katie

2016-06-29

Native plant and beneficial insect associations are relatively unstudied yet are important in native habitat restoration programs for improving and sustaining conservation biological control of arthropod pests in agricultural crops. Milkweeds (Asclepias spp.) are currently the focus of restoration programs in the USA aimed at reversing a decline in populations of the milkweed-dependent monarch butterfly (Danaus plexippus); however, little is known of the benefits of these plants to other beneficial insects. Beneficial insects (predators, parasitoids, pollinators) attracted to two milkweed species (Asclepias speciosa, Asclepias fascicularis) in central Washington State, WA, USA were identified and counted on transparent sticky traps attached to blooms over five seasons. Combining all categories of beneficial insects, means of 128 and 126 insects per trap were recorded for A. speciosa and A. fascicularis, respectively. Predatory and parasitic flies dominated trap catches for A. speciosa while parasitic wasps were the most commonly trapped beneficial insects on A. fascicularis. Bees were trapped commonly on both species, especially A. speciosa with native bees trapped in significantly greater numbers than honey bees. Beneficial insect attraction to A. speciosa and A. fascicularis was substantial. Therefore, these plants are ideal candidates for habitat restoration, intended to enhance conservation biological control, and for pollinator conservation. In central Washington, milkweed restoration programs for enhancement of D. plexippus populations should also provide benefits for pest suppression and pollinator conservation.

United States Department of Agriculture-Agricultural Research Service research programs on microbes for management of plant-parasitic nematodes.

PubMed

Meyer, Susan L F

2003-01-01

Restrictions on the use of conventional nematicides have increased the need for new methods of managing plant-parasitic nematodes. Consequently, nematode-antagonistic microbes, and active compounds produced by such organisms, are being explored as potential additions to management practices. Programs in this area at the USDA Agricultural Research Service investigate applied biocontrol agents, naturally occurring beneficial soil microbes and natural compounds. Specific research topics include use of plant growth-promoting rhizobacteria and cultural practices for management of root-knot and ring nematodes, determination of management strategies that enhance activity of naturally occurring Pasteuria species (bacterial obligate parasites of nematodes), studies on interactions between biocontrol bacteria and bacterial-feeding nematodes, and screening of microbes for compounds active against plant-parasitic nematodes. Some studies involve biocontrol agents that are active against nematodes and soil-borne plant-pathogenic fungi, or combinations of beneficial bacteria and fungi, to manage a spectrum of plant diseases or to increase efficacy over a broader range of environmental conditions. Effective methods or agents identified in the research programs are investigated as additions to existing management systems for plant-parasitic nematodes.

Stress Response and Artemisinin Resistance in Malaria Parasite

DTIC Science & Technology

2017-07-01

AWARD NUMBER: W81XWH-16-1-0241 TITLE: Stress Response and Artemisinin Resistance in Malaria Parasite PRINCIPAL INVESTIGATOR: Juan C. Pizarro...SUBTITLE Stress Response and Artemisinin Resistance in Malaria Parasite 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-16-1-0241 5c. PROGRAM ELEMENT...explored the role of GRP78, a protein chaperone from the stress response, in arteminisin resistant parasites. The GRP78 expression at the mRNA and

An assessment of interspecific competition between two introduced parasitoids of Diaphorina citri (Hemiptera: Liviidae) on caged citrus plants.

PubMed

Vankosky, Meghan A; Hoddle, Mark S

2017-06-07

Two parasitoids attacking nymphs of Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), Tamarixia radiata (Waterston) (Hymenoptera: Eulophidae) and Diaphorencyrtus aligarhensis (Shafee, Alam & Agarwal) (Hymenoptera: Encyrtidae) are being released in California, USA in a classical biological control program. To evaluate the effect of multiple parasitoid species on D. citri mortality, we conducted mesocosm experiments under controlled conditions using a complete block design with 6 treatments (D. citri nymphs exposed to: no parasitoids; D. aligarhensis or T. radiata alone; D. aligarhensis or T. radiata released first (by 48 h); and both species released simultaneously). Parasitism of D. citri nymphs by T. radiata exceeded 60% and was unchanged when D. aligarhensis were present. Parasitism by D. aligarhensis was greatest when T. radiata was absent (∼28%) and was reduced in all treatments with T. radiata present (<3%). D. citri mortality and parasitoid-related mortality of D. citri was consistent across parasitoid treatments. Laboratory results suggest that competition between D. aligarhensis and T. radiata is asymmetric and favors T. radiata. It may be difficult for D. aligarhensis to contribute significantly to D. citri biological control where T. radiata is present. However, results reported here suggest that competition between T. radiata and D. aligarhensis is not likely to reduce parasitism by T. radiata or reduce parasitoid-induced mortality of D. citri. © 2017 Institute of Zoology, Chinese Academy of Sciences.

Short report: secondary transmission in porcine cysticercosis: description and their potential implications for control sustainability.

PubMed

Gonzalez, Armando E; López-Urbina, Teresa; Tsang, Byron Y; Gavidia, César M; Garcia, Héctor H; Silva, María E; Ramos, Daphne D; Manzanedo, Rafael; Sánchez-Hidalgo, Lelia; Gilman, Robert H; Tsang, Victor C W

2005-09-01

Taenia solium taeniasis/cysticercosis is one of few potentially eradicable infectious diseases and is the target of control programs in several countries. The larval stage of this zoonotic cestode invades the human brain and is responsible for most cases of adult-onset epilepsy in the world. The pig is the natural intermediate host, harboring the larvae or cysticerci. Our current understanding of the life cycle implicates humans as the only definitive host and tapeworm carrier (developing taeniasis) and thus the sole source of infective eggs that are responsible for cysticercosis in both human and pigs through oral-fecal transmission. Here we show evidence of an alternative pig-to-pig route of transmission, previously not suspected to exist. In a series of four experiments, naive sentinel pigs were exposed to pigs that had been infected orally with tapeworm segments (containing infective eggs) and moved to a clean environment. Consistently in all four experiments, at least one of the sentinel pigs became seropositive or infected with parasite cysts with much lower cyst burdens than did primarily infected animals. Second-hand transmission of Taenia solium eggs could explain the overdispersed pattern of porcine cysticercosis, with few pigs harboring heavy parasite burdens and many more harboring small numbers of parasites. This route of transmission opens new avenues for consideration with respect to control strategies.

Local host specialization, host-switching, and dispersal shape the regional distributions of avian haemosporidian parasites.

PubMed

Ellis, Vincenzo A; Collins, Michael D; Medeiros, Matthew C I; Sari, Eloisa H R; Coffey, Elyse D; Dickerson, Rebecca C; Lugarini, Camile; Stratford, Jeffrey A; Henry, Donata R; Merrill, Loren; Matthews, Alix E; Hanson, Alison A; Roberts, Jackson R; Joyce, Michael; Kunkel, Melanie R; Ricklefs, Robert E

2015-09-08

The drivers of regional parasite distributions are poorly understood, especially in comparison with those of free-living species. For vector-transmitted parasites, in particular, distributions might be influenced by host-switching and by parasite dispersal with primary hosts and vectors. We surveyed haemosporidian blood parasites (Plasmodium and Haemoproteus) of small land birds in eastern North America to characterize a regional parasite community. Distributions of parasite populations generally reflected distributions of their hosts across the region. However, when the interdependence between hosts and parasites was controlled statistically, local host assemblages were related to regional climatic gradients, but parasite assemblages were not. Moreover, because parasite assemblage similarity does not decrease with distance when controlling for host assemblages and climate, parasites evidently disperse readily within the distributions of their hosts. The degree of specialization on hosts varied in some parasite lineages over short periods and small geographic distances independently of the diversity of available hosts and potentially competing parasite lineages. Nonrandom spatial turnover was apparent in parasite lineages infecting one host species that was well-sampled within a single year across its range, plausibly reflecting localized adaptations of hosts and parasites. Overall, populations of avian hosts generally determine the geographic distributions of haemosporidian parasites. However, parasites are not dispersal-limited within their host distributions, and they may switch hosts readily.

Parasites that cause problems in Malaysia: soil-transmitted helminths and malaria parasites.

PubMed

Singh, B; Cox-Singh, J

2001-12-01

Malaysia is a developing country with a range of parasitic infections. Indeed, soil-transmitted helminths and malaria parasites continue to have a significant impact on public health in Malaysia. In this article, the prevalence and distribution of these parasites, the problems associated with parasitic infections, the control measures taken to deal with these parasites and implications for the future will be discussed.

Identification of Wolbachia Strains in Mosquito Disease Vectors

PubMed Central

Osei-Poku, Jewelna; Han, Calvin; Mbogo, Charles M.; Jiggins, Francis M.

2012-01-01

Wolbachia bacteria are common endosymbionts of insects, and some strains are known to protect their hosts against RNA viruses and other parasites. This has led to the suggestion that releasing Wolbachia-infected mosquitoes could prevent the transmission of arboviruses and other human parasites. We have identified Wolbachia in Kenyan populations of the yellow fever vector Aedes bromeliae and its relative Aedes metallicus, and in Mansonia uniformis and Mansonia africana, which are vectors of lymphatic filariasis. These Wolbachia strains cluster together on the bacterial phylogeny, and belong to bacterial clades that have recombined with other unrelated strains. These new Wolbachia strains may be affecting disease transmission rates of infected mosquito species, and could be transferred into other mosquito vectors as part of control programs. PMID:23185484

Control strategies for a stochastic model of host-parasite interaction in a seasonal environment.

PubMed

Gómez-Corral, A; López García, M

2014-08-07

We examine a nonlinear stochastic model for the parasite load of a single host over a predetermined time interval. We use nonhomogeneous Poisson processes to model the acquisition of parasites, the parasite-induced host mortality, the natural (no parasite-induced) host mortality, and the reproduction and death of parasites within the host. Algebraic results are first obtained on the age-dependent distribution of the number of parasites infesting the host at an arbitrary time t. The interest is in control strategies based on isolation of the host and the use of an anthelmintic at a certain intervention instant t0. This means that the host is free living in a seasonal environment, and it is transferred to a uninfected area at age t0. In the uninfected area, the host does not acquire new parasites, undergoes a treatment to decrease the parasite load, and its natural and parasite-induced mortality are altered. For a suitable selection of t0, we present two control criteria that appropriately balance effectiveness and cost of intervention. Our approach is based on simple probabilistic principles, and it allows us to examine seasonal fluctuations of gastrointestinal nematode burden in growing lambs. Copyright © 2014 Elsevier Ltd. All rights reserved.

The Lawa model: A sustainable, integrated opisthorchiasis control program using the EcoHealth approach in the Lawa Lake region of Thailand.

PubMed

Sripa, Banchob; Tangkawattana, Sirikachorn; Sangnikul, Thinnakorn

2017-08-01

Opisthorchiasis caused by the carcinogenic liver fluke Opisthorchis viverrini is a major foodborne parasitic zoonotic disease in Thailand and neighboring Mekong countries. The infection is associated with several hepatobiliary diseases including cholangiocarcinoma (CCA). The rates of CCA in regions where the parasite is endemic are unprecedented. Extensive research on various aspects of opisthorchiasis has been conducted in recent decades. However, the current status of O. viverrini infection in the country is approaching 85% prevalence in certain endemic areas even after more than 30years of control programs in Thailand. The complex life cycle of the fluke, which involves several hosts/environments, makes it difficult to control by conventional methods. Therefore, a new control strategy using the EcoHealth/One Health approach named the "Lawa model" was introduced into the liver fluke endemic Lawa Lake region in Khon Kaen Province. This program has been underway for over ten years. The program includes treatment with anthelmintic drugs, novel intensive health education methods both in the communities and in schools, ecosystem monitoring and active community participation. We developed the "Liver fluke-free school program" as a part of the Lawa model with successful results. All key stakeholders were empowered to obtain competency in their control activities for the sustainability of the program in the community. Nowadays, the infection rate in the 12 villages surrounding the lake has declined to less than 10% from an average of 60% at the start. The Cyprinid fish species now show less than 1% prevalence of infection compared with a maximum of 70% during the baseline survey. No infected Bithynia snails in the lake were found during recent field studies. Of the lessons learned from the Lawa model, the importance of community participation is one practical and essential component. The key to the success of the project is multi-stakeholder participation with the active local Health Promoting Hospitals and the village health volunteers. The idea of the Lawa model is on the national agenda against liver fluke infection and CCA and is being scaled up to work in larger areas in Thailand. Internationally, the "Lawa model" is one of two programs that are showcased as successful control programs for helminths by the WHO Neglected Zoonotic Diseases (NZD4). Several media outlets have broadcast news reports about the program. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Neotropical Zoonotic Parasites in Bush Dogs (Speothos venaticus) from Upper Paraná Atlantic Forests in Misiones, Argentina.

PubMed

Vizcaychipi, Katherina A; Rinas, Miguel; Irazu, Lucia; Miyagi, Adriana; Argüelles, Carina F; DeMatteo, Karen E

2016-10-01

Wildlife remains an important source of zoonotic diseases for the most vulnerable groups of humans, primarily those living in rural areas or coexisting with forest. The Upper Paraná Atlantic forest of Misiones, Argentina is facing ongoing environmental and anthropogenic changes, which affect the local biodiversity, including the bush dog (Speothos venaticus), a small canid considered Near Threatened globally and Endangered locally. This project aimed to expand the knowledge of zoonotic parasites present in the bush dog and the potential implications for human health and conservation medicine. From May to August 2011, a detection dog located 34 scats that were genetically confirmed as bush dog and georeferenced to northern Misiones. Of these 34 scats, 27 had sufficient quantity that allowed processing for zoonotic parasites using morphological (sedimentation and flotation) and antigen (coproantigen technique) analyses. Within these 27 scats, we determined that the parasitic prevalence was 63.0% (n = 17) with 8 (47.1%) having mixed infections with 2-4 parasitic genera. No significant differences (p > 0.05) between sampling areas, sex, and parasite taxa were found. We were able to summarize the predominant nematodes (Ancylostoma caninum, Toxocara canis, and Lagochilascaris spp.), cestodes (Taenia spp. and Spirometra spp.), and apicomplexa (Cystoisospora caninum) found in these bush dogs. With the copro-ELISA technique, 14.8% (n = 4) of the samples were positive for Echinococcus spp. This study represents the first comprehensive study about parasitic fauna with zoonotic potential in the free-ranging bush dog. This information combined with the innovative set of techniques used to collect the samples constitute a valuable contribution that can be used in control programs, surveillance of zoonotic diseases, and wildlife conservation, both regionally and across the bush dog's broad distribution.

Control of intestinal parasitic infections in Seychelles: a comprehensive and sustainable approach.

PubMed Central

Albonico, M.; Shamlaye, N.; Shamlaye, C.; Savioli, L.

1996-01-01

Intestinal parasitic infections have been perceived as a public health problem in Seychelles for decades. A comprehensive strategy to reduce morbidity and, in the long term, transmission of intestinal parasites has been implemented successfully since 1993. Management of the programme is integrated into the well established primary health care system, with control activities being undertaken through existing health facilities. The strategy is based on periodic chemotherapy of schoolchildren, intense health education and improvement of sanitation and safe water supply. The initial objectives of the control programme were met after 2 years of activities, with an overall reduction in prevalence of intestinal parasitic infections of 44%. The intensity of infection with Trichuris trichiura, the commonest parasite, was halved (from 780 to 370 eggs per g of faeces). The programme's integrated approach, in concert with political commitment and limited operational costs, is a warranty for the future sustainability of control activities. The programme can be seen as a model for other developing countries, even where health and socioeconomic conditions are different and the control of parasitic infections will need a much longer-term commitment. PMID:9060217

Epigenetic modulation, stress and plasticity in susceptibility of the snail host, Biomphalaria glabrata, to Schistosoma mansoni infection.

PubMed

Knight, Matty; Ittiprasert, Wannaporn; Arican-Goktas, Halime D; Bridger, Joanna M

2016-06-01

Blood flukes are the causative agent of schistosomiasis - a major neglected tropical disease that remains endemic in numerous countries of the tropics and sub-tropics. During the past decade, a concerted effort has been made to control the spread of schistosomiasis, using a drug intervention program aimed at curtailing transmission. These efforts notwithstanding, schistosomiasis has re-emerged in southern Europe, raising concerns that global warming could contribute to the spread of this disease to higher latitude countries where transmission presently does not take place. Vaccines against schistosomiasis are not currently available and reducing transmission by drug intervention programs alone does not prevent reinfection in treated populations. These challenges have spurred awareness that new interventions to control schistosomiasis are needed, especially since the World Health Organization hopes to eradicate the disease by 2025. For one of the major species of human schistosomes, Schistosoma mansoni, the causative agent of hepatointestinal schistosomiasis in Africa and the Western Hemisphere, freshwater snails of the genus Biomphalaria serve as the obligate intermediate host of this parasite. To determine mechanisms that underlie parasitism by S. mansoni of Biomphalaria glabrata, which might be manipulated to block the development of intramolluscan larval stages of the parasite, we focused effort on the impact of schistosome infection on the epigenome of the snail. Results to date reveal a complex relationship, manifested by the ability of the schistosome to manipulate the snail genome, including the expression of specific genes. Notably, the parasite subverts the stress response of the host to ensure productive parasitism. Indeed, in isolates of B. glabrata native to central and South America, susceptible to infection with S. mansoni, the heat shock protein 70 (Bg-HSP70) gene of this snail is rapidly relocated in the nucleus and transcribed to express HSP70. Concurrently, hypomethylation of the CpG sites, within the Bg-HSP70 intergenic DNA region, proceeds by conveying epigenetic and spatio-epigenetic mechanisms in temporal concordance. It is notable that this is only the second example reported where a pathogen has been shown to control host cell spatio-epigenetics for its own advantage. Nonetheless, the remarkable mechanisms through which genes become activated i.e. DNA and chromatin remodeling and relocation to a nuclear compartment conducive to gene expression may represent novel intervention targets. Copyright © 2016 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

Parasitic plants in agriculture: Chemical ecology of germination and host-plant location as targets for sustainable control: A review

Treesearch

Justin B. Runyon; John F. Tooker; Mark C. Mescher; Consuelo M. De Moraes

2009-01-01

Parasitic plants are among the most problematic pests of agricultural crops worldwide. Effective means of control are generally lacking, in part because of the close physiological connection between the established parasite and host plant hindering efficient control using traditional methods. Seed germination and host location are critical early-growth stages that...

Automated Design Tools for Integrated Mixed-Signal Microsystems (NeoCAD)

DTIC Science & Technology

2005-02-01

method, Model Order Reduction (MOR) tools, system-level, mixed-signal circuit synthesis and optimization tools, and parsitic extraction tools. A unique...Mission Area: Command and Control mixed signal circuit simulation parasitic extraction time-domain simulation IC design flow model order reduction... Extraction 1.2 Overall Program Milestones CHAPTER 2 FAST TIME DOMAIN MIXED-SIGNAL CIRCUIT SIMULATION 2.1 HAARSPICE Algorithms 2.1.1 Mathematical Background

Durably controlling bovine hypodermosis.

PubMed

Boulard, Chantal

2002-01-01

Cattle hypodermosis, due to insect larvae, is widely spread over the northern hemisphere. Very efficient insecticides are available and their use in most countries are done on an individual level but never cover the whole cattle population of a country. Untreated animals remain the reservoir of the disease and annually re-infest the cattle population. The economic effects of this disease on animal production (meat, milk and the leather industry) but also on the general cattle health status, have led many European countries to launch organised control programs. The first example of definitive hypodermosis control goes back one hundred years ago when Danish farmers eradicated hypodermosis from the Danish islands by manual elimination of the warbles. Since then, more and more European countries have considered the feasibility and economic returns of such programs. The various factors which foster these programs are related to (i) biological factors, (parasite cattle specificity, synchronous biological cycles of both species of insects involved), (ii) the development of more and more efficient insecticides used only once a year by systemic application, with high efficiency at very low dosages against the first larval stage of Hypoderma spp., (iii) the development of acute techniques of detection of the disease for the monitoring of hypodermosis free countries and (iv) the durable successful results obtained in more and more European countries. Although the programs were imposed by different partners of the livestock channel production (farmers, dairy industry, leather industry) and have been engaged within the last 50 years in many European countries (Denmark, The Netherlands, Ireland, the United Kingdom, the Czech Republic, Germany, France and Switzerland) common features have emerged among these different eradication programs. They all need a preliminary statement of the economic impact of this pest and the farmers' awareness of the economic returns of such programs. The programs' efficacy depends: (i) on a good knowledge ofthe epidemiology of the parasites, (ii) on the simultaneous implementation of the control program on the whole national cattle population whatever the structure monitoring the treatments (veterinary services, farmers association), (iii) on a national Warble fly legislation making the treatments compulsory and (iv) on an acute epidemiological survey as soon as the status of a hypodermosis free country is reached and the treatments are suspended. The sanitary and financial returns of such programs are a benefit to all the partners of livestock production, to the quality of the environment and to the consumers.

Prevalence of Intestinal Parasite Infections among Individuals with Mental Retardation in New York State.

ERIC Educational Resources Information Center

Schupf, Nicole; And Others

1995-01-01

Prevalence of intestinal parasite infection among program participants of the New York State Office of Mental Retardation and Developmental Disabilities for 1986-87 was estimated at 7.3%, suggesting that management of parasitic infection is improving. Males and individuals with severe/profound mental retardation were twice as likely to have…

In sickness or in health: TDR's partners. 6. The French Development Research Institute (ORSTOM).

PubMed

1997-10-01

One of the partner agencies working with the UN Development Program/World Bank/World Health Organization Special Programme for Research and Training in Tropical Diseases (TDR) is the French development research agency, ORSTOM. ORSTOM has been conducting research in intertropical regions for approximately 50 years with a particular focus on entomoparasitological aspects of vector-borne diseases. ORSTOM's close collaboration with TDR since the TDR Special Program was launched in 1975 has led to 1) improved knowledge about various aspects of trypanosomiasis that allowed identification of ways to control the epidemic; 2) reappraisal of the taxonomy of the parasitic protozoa responsible for Chagas disease and leishmaniasis; 3) improvements in the strategy to fight malaria; 4) assessment of the efficacy of ivermectin as a form of mass treatment for onchocerciasis; 5) improved knowledge about dracunculiasis that contributed to an eradication campaign; 6) expansion of the scope of biological control of bancroftian filariasis and other parasites; and 7) improved knowledge about ways to control two schistosome species. ORSTOM also participated in a training and structural enhancement initiative that resulted in creation of the Boake Medical and Veterinary Entomology Training Center. ORSTOM is currently undergoing a complete restructuring to respond to changes in international tropical disease research and to changing priorities that focus on vector-borne diseases, nutrition, AIDS, and health systems.

Trichinae certification in the United States pork industry.

PubMed

Pyburn, David G; Gamble, H Ray; Wagstrom, Elizabeth A; Anderson, Lowell A; Miller, Lawrence E

2005-09-05

Control of Trichinella infection in U.S. pork has traditionally been accomplished by inspection of individual carcasses at slaughter or by post-slaughter processing to inactivate parasites. We propose that an alternative to individual carcass testing or processing can be used when pigs are raised in production systems where risk of exposure to Trichinella spiralis has been mitigated. Declines in prevalence of this parasite in U.S. domestic swine during the last 30 years, coupled with improvements in pork production systems, now allow Trichinella control to be shifted to the farm through implementation of specific pork production practices. Knowledge of risk factors for exposure of swine to T. spiralis was used to develop an objective audit of risk that can be applied to pork production sites. In a pilot study, 461 production site audits were performed by trained veterinary practitioners. The on-farm audit included aspects of farm management, bio-security, feed and feed storage, rodent control programs and general hygiene. Of the 461 production site audits, 450 audits (97.6%) indicated compliance with the required good production practices. These sites are eligible for certification under the U.S. Trichinae Certification Program and will be audited regularly to maintain that status. The described trichinae certification mechanism will establish a process for ensuring the Trichinella safety of swine, and ultimately food products derived from swine, at the production level.

Control of human parasitic diseases: Context and overview.

PubMed

Molyneux, David H

2006-01-01

The control of parasitic diseases of humans has been undertaken since the aetiology and natural history of the infections was recognized and the deleterious effects on human health and well-being appreciated by policy makers, medical practitioners and public health specialists. However, while some parasitic infections such as malaria have proved difficult to control, as defined by a sustained reduction in incidence, others, particularly helminth infections can be effectively controlled. The different approaches to control from diagnosis, to treatment and cure of the clinically sick patient, to control the transmission within the community by preventative chemotherapy and vector control are outlined. The concepts of eradication, elimination and control are defined and examples of success summarized. Overviews of the health policy and financing environment in which programmes to control or eliminate parasitic diseases are positioned and the development of public-private partnerships as vehicles for product development or access to drugs for parasite disease control are discussed. Failure to sustain control of parasites may be due to development of drug resistance or the failure to implement proven strategies as a result of decreased resources within the health system, decentralization of health management through health-sector reform and the lack of financial and human resources in settings where per capita government expenditure on health may be less than $US 5 per year. However, success has been achieved in several large-scale programmes through sustained national government investment and/or committed donor support. It is also widely accepted that the level of investment in drug development for the parasitic diseases of poor populations is an unattractive option for pharmaceutical companies. The development of partnerships to specifically address this need provides some hope that the intractable problems of the treatment regimens for the trypanosomiases and leishmaniases can be solved in the not too distant future. However, it will be difficult to implement and sustain such interventions in fragile health services often in settings where resources are limited but also in unstable, conflict-affected or post-conflict countries. Emphasis is placed on the importance of co-endemicity and polyparasitism and the opportunity to control parasites susceptible to cost-effective and proven chemotherapeutic interventions for a package of diseases which can be implemented at low cost and which would benefit the poorest and most marginalized groups. The ecology of parasitic diseases is discussed in the context of changing ecology, environment, sociopolitical developments and climate change. These drivers of global change will affect the epidemiology of parasites over the coming decades, while in many of the most endemic and impoverished countries parasitic infections will be accorded lower priority as resourced stressed health systems cope with the burden of the higher-profile killing diseases viz., HIV/AIDS, TB and malaria. There is a need for more holistic thinking about the interactions between parasites and other infections. It is clear that as the prevalence and awareness of HIV has increased, there is a growing recognition of a host of complex interactions that determine disease outcome in individual patients. The competition for resources in the health as well as other social sectors will be a continuing challenge; effective parasite control will be dependent on how such resources are accessed and deployed to effectively address well-defined problems some of which are readily amenable to successful interventions with proven methods. In the health sector, the problems of the HIV/AIDS and TB pandemics and the problem of the emerging burden of chronic non-communicable diseases will be significant competitors for these limited resources as parasitic infections aside from malaria tend to be chronic disabling problems of the poorest who have limited access to scarce health services and are representative of the poorest quintile. Prioritization and advocacy for parasite control in the national and international political environments is the challenge.

Analytical design of a parasitic-loading digital speed controller for a 400-hertz turbine driven alternator

NASA Technical Reports Server (NTRS)

Ingle, B. D.; Ryan, J. P.

1972-01-01

A design for a solid-state parasitic speed controller using digital logic was analyzed. Parasitic speed controllers are used in space power electrical generating systems to control the speed of turbine-driven alternators within specified limits. The analysis included the performance characteristics of the speed controller and the generation of timing functions. The speed controller using digital logic applies step loads to the alternator. The step loads conduct for a full half wave starting at either zero or 180 electrical degrees.

Congenital Chagas disease as an ecological model of interactions between Trypanosoma cruzi parasites, pregnant women, placenta and fetuses.

PubMed

Carlier, Yves; Truyens, Carine

2015-11-01

The aim of this paper is to discuss the main ecological interactions between the parasite Trypanosoma cruzi and its hosts, the mother and the fetus, leading to the transmission and development of congenital Chagas disease. One or several infecting strains of T. cruzi (with specific features) interact with: (i) the immune system of a pregnant woman whom responses depend on genetic and environmental factors, (ii) the placenta harboring its own defenses, and, finally, (iii) the fetal immune system displaying responses also susceptible to be modulated by maternal and environmental factors, as well as his own genetic background which is different from her mother. The severity of congenital Chagas disease depends on the magnitude of such final responses. The paper is mainly based on human data, but integrates also complementary observations obtained in experimental infections. It also focuses on important gaps in our knowledge of this congenital infection, such as the role of parasite diversity vs host genetic factors, as well as that of the maternal and placental microbiomes and the microbiome acquisition by infant in the control of infection. Investigations on these topics are needed in order to improve the programs aiming to diagnose, manage and control congenital Chagas disease. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Vaccination of chickens against coccidiosis ameliorates drug resistance in commercial poultry production

PubMed Central

Chapman, H. David; Jeffers, Thomas K.

2014-01-01

Drug resistance is a problem wherever livestock are raised under intensive conditions and drugs are used to combat parasitic infections. This is particularly true for the anticoccidial agents used for the prevention of coccidiosis caused by protozoa of the apicomplexan genus Eimeria in poultry. Resistance has been documented for all the dozen or so drugs approved for use in chickens and varying levels of resistance is present for those currently employed. A possible solution may be the introduction of drug-sensitive parasites into the houses where poultry are raised so that they may replace such drug-resistant organisms. This can be achieved by utilizing live vaccines that contain strains of Eimeria that were isolated before most anticoccidial compounds were introduced. Such strains are inherently drug-sensitive. Practical proposals to achieve this objective involve the alternation of vaccination with medication (known as rotation programs) in successive flocks reared in the same poultry house. A proposal for a yearly broiler production cycle involving chemotherapy and vaccination is presented. There are few, if any, examples in veterinary parasitology where it has proved possible to restore sensitivity to drugs used to control a widespread parasite. Further research is necessary to ascertain whether this can result in sustainable and long-term control of Eimeria infections in poultry. PMID:25516830

The integrated project: a promising promotional strategy for primary health care.

PubMed

Daniel, C; Mora, B

1985-10-01

The integrated project using parasite control and nutrition as entry points for family planning practice has shown considerable success in promoting health consciousness among health workers and project beneficiaries. This progress is evident in the Family Planning, Parasite Control and Nutrition (FAPPCAN) areas. The project has also mobilized technical and financial support from the local government as well as from private and civic organizations. The need for integration is underscored by the following considerations: parasite control has proved to be effective for preventive health care; the integrated project uses indigenous community health workers to accomplish its objectives; the primary health care (PHC) movement depends primarily on voluntary community participation and the integrated project has shown that it can elicit this participation. The major health problems in the Philippines are: a prevalence of communicable and other infectious diseases; poor evironmental sanitation; malnutrition; and a rapid population growth rate. The integrated program utilizes the existing village health workers in identifying problems related to family planning, parasite control and nutrition and integrates these activities into the health delivery system; educates family members on how to detect health and health-related problems; works out linkages with government agencies and the local primary health care committee in defining the scope of health-related problems; mobilizes community members to initiate their own projects; gets the commitment of village officials and committe members. The integrated project operates within the PHC. A health van with a built-in video playback system provides educational and logistical support to the village worker. The primary detection and treatment of health problems are part of the village health workers' responsibilities. Research determines the project's capability to reactivate the village primary health care committees and sustain community commitment. The project initially covered 4 villages. Implementation problems included: inactive village health workers, inadequate supervision and monitoring of PHC, a lack of commitment of committee members, and the lack of financial support.

[Effect of comprehensive control in demonstration plots of parasitic diseases in Guizhou Province].

PubMed

Ai-Ya, Zhu; An-Mei, Li; Guang-Chu, Lin; Jian-Jun, Xu; Liang-Xian, Sun

2011-10-01

To evaluate the effect of comprehensive control in demonstration plots of parasitic diseases in Guizhou Province. The data of parasitic disease control in demonstration plots from 2006 to 2009 were collected and analyzed, including deworming, water and latrines renovation, health education, survey on infections in crowd, etc. After 3 years comprehensive control, the infection rates of soil-transmitted nematodes among people reduced from 30.25% to 8.37%, with the reduction rate of 72.32%. The infection rates of Ascaris lumbricoides, hookworm and Trichuris trichiura reduced from 26.88%, 2.86% and 4.13% to 7.43%, 0.09% and 1.13%, respectively. The awareness rate of health knowledge among residents increased from 44.18% to 93.64%, with an increasing rate of 111.94%. The coverage rate of non-hazardous sanitary latrines was 81.29%. The beneficial rate of the water renovation reached 96.31%. The comprehensive control strategies mainly based on health education and infectious source control correspond to the reality of rural parasitic disease control nowadays. The comprehensive control model integrating government leadership, department cooperation and social concern is useful for parasitic disease control and should be popularized.

Regulation of gene expression in protozoa parasites.

PubMed

Gomez, Consuelo; Esther Ramirez, M; Calixto-Galvez, Mercedes; Medel, Olivia; Rodríguez, Mario A

2010-01-01

Infections with protozoa parasites are associated with high burdens of morbidity and mortality across the developing world. Despite extensive efforts to control the transmission of these parasites, the spread of populations resistant to drugs and the lack of effective vaccines against them contribute to their persistence as major public health problems. Parasites should perform a strict control on the expression of genes involved in their pathogenicity, differentiation, immune evasion, or drug resistance, and the comprehension of the mechanisms implicated in that control could help to develop novel therapeutic strategies. However, until now these mechanisms are poorly understood in protozoa. Recent investigations into gene expression in protozoa parasites suggest that they possess many of the canonical machineries employed by higher eukaryotes for the control of gene expression at transcriptional, posttranscriptional, and epigenetic levels, but they also contain exclusive mechanisms. Here, we review the current understanding about the regulation of gene expression in Plasmodium sp., Trypanosomatids, Entamoeba histolytica and Trichomonas vaginalis.

Relationship of parasites and pathologies to contaminant body burden in sentinel bivalves: NOAA Status and Trends 'Mussel Watch' Program.

PubMed

Kim, Yungkul; Powell, Eric N; Wade, Terry L; Presley, Bobby J

2008-03-01

The 1995-1998 database from NOAA's National Status and Trends 'Mussel Watch' Program was used to compare the distributional patterns of parasites and pathologies with contaminant body burdens. Principal components analysis (PCA) resolved five groups of contaminants in both mussels and oysters: one dominated by polycyclic aromatic hydrocarbons (PAHs), one dominated by pesticides, and three dominated by metals. Metals produced a much more complex picture of spatial trends in body burden than did either the pesticides or PAHs. Contrasted to the relative simplicity of the contaminant groupings, PCA exposed a suite of parasite/pathology groups with few similarities between the sentinel bivalve taxa. Thus, the relationship between parasites/pathologies and contaminants differs significantly between taxa despite the similarity in contaminant pattern. Moreover, the combined effects of many contaminants and parasites may be important, leading to complex biological-contaminant interactions with synergies both of biological and chemical origin. Overall, correlations between parasites/pathologies and contaminants were more frequent with metals, frequent with pesticides, and less frequent with PAHs in mussels. In oysters, correlations with pesticides and metals were about equally frequent, but correlations with PAHs were still rare. In mytilids, correlations with metals predominated. Negative and positive correlations with metals occurred with about the same frequency in both taxa. The majority of correlations with pesticides were negative in oysters; not so for mytilids. Of the many significant correlations involving parasites, few involved single-celled eukaryotes or prokaryotes. The vast majority involved multi-cellular eukaryotes and nearly all of them either cestodes, trematode sporocysts, or trematode metacercariae. The few correlations for single-celled parasites all involved proliferating protozoa or protozoa reaching high body burdens through transmission. The tendency for the larger or more numerous parasites to be involved suggests that unequal sequestration of contaminates between host and parasite tissue is a potential mediator. An alternative is that contaminants differentially affect parasites and their hosts by varying host susceptibility or parasite survival.

Population genetics of Schistosoma japonicum within the Philippines suggest high levels of transmission between humans and dogs.

PubMed

Rudge, James W; Carabin, Hélène; Balolong, Ernesto; Tallo, Veronica; Shrivastava, Jaya; Lu, Da-Bing; Basáñez, María-Gloria; Olveda, Remigio; McGarvey, Stephen T; Webster, Joanne P

2008-01-01

Schistosoma japonicum, which remains a major public health problem in the Philippines and mainland China, is the only schistosome species for which zoonotic transmission is considered important. While bovines are suspected as the main zoonotic reservoir in parts of China, the relative contributions of various non-human mammals to S. japonicum transmission in the Philippines remain to be determined. We examined the population genetics of S. japonicum in the Philippines in order to elucidate transmission patterns across host species and geographic areas. S. japonicum miracidia (hatched from eggs within fecal samples) from humans, dogs, pigs and rats, and cercariae shed from snail-intermediate hosts, were collected across two geographic areas of Samar Province. Individual isolates were then genotyped using seven multiplexed microsatellite loci. Wright's F(ST) values and phylogenetic trees calculated for parasite populations suggest a high frequency of parasite gene-flow across definitive host species, particularly between dogs and humans. Parasite genetic differentiation between areas was not evident at the definitive host level, possibly suggesting frequent import and export of infections between villages, although there was some evidence of geographic structuring at the snail-intermediate host level. These results suggest very high levels of transmission across host species, and indicate that the role of dogs should be considered when planning control programs. Furthermore, a regional approach to treatment programs is recommended where human migration is extensive.

Trichinella spiralis: the evolution of adaptation and parasitism

USDA-ARS?s Scientific Manuscript database

Parasitism among nematodes has occurred in multiple, independent events. Deciphering processes that drive species diversity and adaptation are keys to understanding parasitism and advancing control strategies. Studies have been put forth on morphological and physiological aspects of parasitism and a...

Parasites resistant to the antimalarial atovaquone fail to transmit by mosquitoes.

PubMed

Goodman, Christopher D; Siregar, Josephine E; Mollard, Vanessa; Vega-Rodríguez, Joel; Syafruddin, Din; Matsuoka, Hiroyuki; Matsuzaki, Motomichi; Toyama, Tomoko; Sturm, Angelika; Cozijnsen, Anton; Jacobs-Lorena, Marcelo; Kita, Kiyoshi; Marzuki, Sangkot; McFadden, Geoffrey I

2016-04-15

Drug resistance compromises control of malaria. Here, we show that resistance to a commonly used antimalarial medication, atovaquone, is apparently unable to spread. Atovaquone pressure selects parasites with mutations in cytochrome b, a respiratory protein with low but essential activity in the mammalian blood phase of the parasite life cycle. Resistance mutations rescue parasites from the drug but later prove lethal in the mosquito phase, where parasites require full respiration. Unable to respire efficiently, resistant parasites fail to complete mosquito development, arresting their life cycle. Because cytochrome b is encoded by the maternally inherited parasite mitochondrion, even outcrossing with wild-type strains cannot facilitate spread of resistance. Lack of transmission suggests that resistance will be unable to spread in the field, greatly enhancing the utility of atovaquone in malaria control. Copyright © 2016, American Association for the Advancement of Science.

Telescience operations with the solar array module plasma interaction experiment

NASA Technical Reports Server (NTRS)

Wald, Lawrence W.; Bibyk, Irene K.

1995-01-01

The Solar Array Module Plasma Interactions Experiment (SAMPIE) is a flight experiment that flew on the Space Shuttle Columbia (STS-62) in March 1994, as part of the OAST-2 mission. The overall objective of SAMPIE was to determine the adverse environmental interactions within the space plasma of low earth orbit (LEO) on modern solar cells and space power system materials which are artificially biased to high positive and negative direct current (DC) voltages. The two environmental interactions of interest included high voltage arcing from the samples to the space plasma and parasitic current losses. High voltage arcing can cause physical damage to power system materials and shorten expected hardware life. parasitic current losses can reduce power system efficiency because electric currents generated in a power system drain into the surrounding plasma via parasitic resistance. The flight electronics included two programmable high voltage DC power supplies to bias the experiment samples, instruments to measure the surrounding plasma environment in the STS cargo bay, and the on-board data acquisition system (DAS). The DAS provided in-flight experiment control, data storage, and communications through the Goddard Space Flight Center (GSFC) Hitchhiker flight avionics to the GSFC Payload Operations Control Center (POCC). The DAS and the SAMPIE POCC computer systems were designed for telescience operations; this paper will focus on the experiences of the SAMPIE team regarding telescience development and operations from the GSFC POCC during STS-62. The SAMPIE conceptual development, hardware design, and system verification testing were accomplished at the NASA Lewis Research Center (LeRC). SAMPIE was developed under the In-Space Technology Experiment Program (IN-STEP), which sponsors NASA, industry, and university flight experiments designed to enable and enhance space flight technology. The IN-STEP Program is sponsored by the Office of Space Access and Technology (OSAT).

Short report: entomologic inoculation rates and Plasmodium falciparum malaria prevalence in Africa.

PubMed

Beier, J C; Killeen, G F; Githure, J I

1999-07-01

Epidemiologic patterns of malaria infection are governed by environmental parameters that regulate vector populations of Anopheles mosquitoes. The intensity of malaria parasite transmission is normally expressed as the entomologic inoculation rate (EIR), the product of the vector biting rate times the proportion of mosquitoes infected with sporozoite-stage malaria parasites. Malaria transmission intensity in Africa is highly variable with annual EIRs ranging from < 1 to > 1,000 infective bites per person per year. Malaria control programs often seek to reduce morbidity and mortality due to malaria by reducing or eliminating malaria parasite transmission by mosquitoes. This report evaluates data from 31 sites throughout Africa to establish fundamental relationships between annual EIRs and the prevalence of Plasmodium falciparum malaria infection. The majority of sites fitted a linear relationship (r2 = 0.71) between malaria prevalence and the logarithm of the annual EIR. Some sites with EIRs < 5 infective bites per year had levels of P. falciparum prevalence exceeding 40%. When transmission exceeded 15 infective bites per year, there were no sites with prevalence rates < 50%. Annual EIRs of 200 or greater were consistently associated with prevalence rates > 80%. The basic relationship between EIR and P. falciparum prevalence, which likely holds in east and west Africa, and across different ecologic zones, shows convincingly that substantial reductions in malaria prevalence are likely to be achieved only when EIRs are reduced to levels less than 1 infective bite per person per year. The analysis also highlights that the EIR is a more direct measure of transmission intensity than traditional measures of malaria prevalence or hospital-based measures of infection or disease incidence. As such, malaria field programs need to consider both entomologic and clinical assessments of the efficacy of transmission control measures.

Identifying Geographic Areas at Risk of Soil-transmitted Helminthes Infection Using Remote Sensing and Geographical Information Systems: Boaco, Nicaragua as a Case Study

NASA Technical Reports Server (NTRS)

Moreno, Max J.; Al-Hamdan, Mohammad Z.; Parajon, David G.; Rickman, Douglas L.; Luvall, Jeffrey; Estes, Sue; Podest, Erika

2011-01-01

Several types of intestinal nematodes, that can infect humans and specially school-age children living in poverty, develop part of their life cycle in soil. Presence and survival of these parasites in the soil depend on given environmental characteristics like temperature and moisture that can be inferred with remote sensing (RS) technology. Prevalence of diseases caused by these parasitic worms can be controlled and even eradicated with anthelmintic drug treatments and sanitation improvement. Reliable and updated identification of geographic areas at risk is required to implement effective public health programs; to calculate amount of drug required and to distribute funding for sanitation projects. RS technology and geographical information systems (GIS) will be used to analyze for associations between in situ prevalence and remotely sensed data in order to establish RS proxies of environmental parameters that indicate the presence of these parasits. In situ data on helminthisasis will be overlaid over an ecological map derived from RS data using ARC Map 9.3 (ESRI). Temperature, vegetation, and distance to bodies of water will be inferred using data from Moderate-Resolution Imaging Spectroradiometer (MODIS) and Landsat TM and ETM+. Elevation will be estimated with data from The Shuttle Radar Topography Mission (SRTM). Prevalence and intensity of infections are determined by parasitological survey (Kato Katz) of children enrolled in rural schools in Boaco, Nicaragua, in the communities of El Roblar, Cumaica Norte, Malacatoya 1, and Malacatoya 2). This study will demonstrate the importance of an integrated GIS/RS approach to define clusters and areas at risk. Such information will help to the implementation of time and cost efficient control programs and sanitation efforts.

Management practices to control gastrointestinal parasites in dairy and beef goats in Minas Gerais; Brazil.

PubMed

Guimarães, Alessandro de Sá; Gouveia, Aurora Maria Guimarães; do Carmo, Filipe Borges; Gouveia, Gabriela Canabrava; Silva, Marcos Xavier; Vieira, Luiz da Silva; Molento, Marcelo Beltrão

2011-03-10

Parasitic infection is recognized worldwide as a limiting factor in the production of goats, and various control methods are used to reduce economic losses, often without considering the epidemiology of the parasites. This has led to the development of highly tolerant parasite populations and the presence of chemical residues in the beef and milk. The objective of this study was to determine the level of knowledge of goat farmers about parasitic diseases and to correlate this with the epidemiology of endoparasites and parasite control practices in goat farms in the state of Minas Gerais, Brazil. The analysis was based on a questionnaire applied by trained veterinarians. The sample was homogeneous throughout the state, covering 18.4% (157/853) of municipalities. Eighty-four dairy goat farms in 81 municipalities and 200 properties with beef goats in 76 municipalities were evaluated. The herd size per goat farm ranged from 4 to 57 (average 24) for beef herds and from 2 to 308 (average 63) for dairy farms. The majority of the beef herd production was extensive and semi-extensive (98.5%), while the dairy herds were maintained under intensive farming (98.8%). The mixed production of goats and sheep was reported by 36.5% of beef goat farmers and by 20.2% of dairy goat farmers. Among the beef goats farms on which the technological level was determined, 2.0% were categorized as having high technological level, 34.5% as medium, and 63.5% as low. Of the 84 dairy farms, 30% operated at a high, 47% at a medium, and 23% at a low technological level. The adoption of practices to reduce parasitism, such as the quarantine of animals, treatment of newly arrived animals, regular cleaning of the floor, and technical assistance, was significantly higher on dairy farms than on beef farms. Although 85.7% of dairy farmers and 83% of beef farmers medicate their animals, the treatments were performed without technical criteria, and deworming intervals ranged from 30 to 120 days or more. The average interval between treatments was significantly longer in dairy goat herds (4.8 months) than in the beef herds (3.6 months). The most commonly used drugs were macrocyclic lactones (37.7% in dairy and 39.5% in beef herds) and benzimidazoles (48.9% in dairy and 31.5% in beef herds). Goat production in Minas Gerais is still in its infancy, and even though using a control program associated with other health practices, producers still rely heavily on chemicals to get satisfactory results. Copyright © 2011. Published by Elsevier B.V.

Prevalence of intestinal parasitism and associated symptomatology among hemodialysis patients.

PubMed

Gil, Frederico F; Barros, Maxlene J; Macedo, Nazaré A; Júnior, Carmelino G E; Redoan, Roseli; Busatti, Haendel; Gomes, Maria A; Santos, Joseph F G

2013-01-01

Intestinal parasites are an important cause of morbidity and mortality. Immunocompromised individuals may develop more severe forms of these infections. Taking into account the immunity impairment in patients suffering from chronic renal failure (CRF), we will determine the prevalence and associated symptoms of intestinal parasites in these patients. Controls without CRF were used for comparison. Stool samples were collected and processed for microscopic identification of parasites using the Formalin-ether concentration method. For Cryptosporidium diagnosis, the ELISA technique was used. One hundred and ten fecal samples from hemodialysis patients were analyzed, as well as 86 from a community group used as control group. A result of 51.6% of intestinal parasites was observed in hemodialysis patients and 61.6% in the control group. Cryptosporidium and Blastocystis were the most common infections in patients with CRF (26.4% and 24.5%, respectively). Blastocystis was the most common infection in the control group (41.9%), however no individual was found positive for Cryptosporidium. Among the CRF patients, 73.6% were symptomatic, 54.3% of these tested positive for at least one parasite, in contrast to 44.8% in asymptomatic patients (p = 0.38). The most common symptoms in this group were flatulence (36.4%), asthenia (30.0%) and weight loss (30.0%). In the control group, 91.9% were symptomatic, 60.8% of these tested positive for at least one parasite, in contrast to 71.4% in asymptomatic patients (p = 0.703). A significant difference between the two groups was observed with regard to symptoms, with bloating, postprandial fullness, and abdominal pain being more frequent in the control group than in the hemodialysis group (all p < 0.05). Comparing symptomatic with asymptomatic, there was no association in either group between symptoms or the prevalence of parasitic infection, nor with the type of parasite or with multiple parasitic infections. Patients with chronic renal failure are frequent targets for renal transplantation, which as well as the inherent immunological impairment of the disease itself, results in immunosuppression by medication. For this reason, carriers of intestinal parasites with pathogenic potential can develop serious clinical complications influencing the success of transplantation. This fact, coupled with the high prevalence of intestinal parasites and the dissociation between symptoms and infection in CRF patients, suggests that the stool test should be incorporated in routine propedeutics. Furthermore, preventive measures for the acquisition of parasites through the fecal-oral contamination route should be introduced.

Investigation of Amino Acids As Herbicides for Control of Orobanche minor Parasitism in Red Clover.

PubMed

Fernández-Aparicio, Mónica; Bernard, Alexandre; Falchetto, Laurent; Marget, Pascal; Chauvel, Bruno; Steinberg, Christian; Morris, Cindy E; Gibot-Leclerc, Stephanie; Boari, Angela; Vurro, Maurizio; Bohan, David A; Sands, David C; Reboud, Xavier

2017-01-01

Certain amino acids induce inhibitory effects in plant growth due to feedback inhibition of metabolic pathways. The inhibition patterns depend on plant species and the plant developmental stage. Those amino acids with inhibitory action on specific weeds could be utilized as herbicides, however, their use for weed control has not been put into practice. Orobanche minor is a weed that parasitizes red clover. O. minor germination is stimulated by clover root exudates. The subsequent seedling is an obligated parasite that must attach quickly to the clover root to withdraw its nutrients. Early development of O. minor is vulnerable to amino acid inhibition and therefore, a series of in vitro , rhizotron, and field experiments were conducted to investigate the potential of amino acids to inhibit O. minor parasitism. In in vitro experiments it was found that among a collection of 20 protein amino acids, lysine, methionine and tryptophan strongly interfere with O. minor early development. Field research confirmed their inhibitory effect but revealed that methionine was more effective than lysine and tryptophan, and that two successive methionine applications at 308 and 543 growing degree days inhibited O. minor emergence in red clover up to 67%. We investigated additional effects with potential to influence the practical use of amino acids against broomrape weeds, whether the herbicidal effect may be reversible by other amino acids exuded by host plants or may be amplified by inducing host resistance barriers against O. minor penetration. This paper suggests that amino acids may have the potential to be integrated into biorational programs of broomrape management.

Investigation of Amino Acids As Herbicides for Control of Orobanche minor Parasitism in Red Clover

PubMed Central

Fernández-Aparicio, Mónica; Bernard, Alexandre; Falchetto, Laurent; Marget, Pascal; Chauvel, Bruno; Steinberg, Christian; Morris, Cindy E.; Gibot-Leclerc, Stephanie; Boari, Angela; Vurro, Maurizio; Bohan, David A.; Sands, David C.; Reboud, Xavier

2017-01-01

Certain amino acids induce inhibitory effects in plant growth due to feedback inhibition of metabolic pathways. The inhibition patterns depend on plant species and the plant developmental stage. Those amino acids with inhibitory action on specific weeds could be utilized as herbicides, however, their use for weed control has not been put into practice. Orobanche minor is a weed that parasitizes red clover. O. minor germination is stimulated by clover root exudates. The subsequent seedling is an obligated parasite that must attach quickly to the clover root to withdraw its nutrients. Early development of O. minor is vulnerable to amino acid inhibition and therefore, a series of in vitro, rhizotron, and field experiments were conducted to investigate the potential of amino acids to inhibit O. minor parasitism. In in vitro experiments it was found that among a collection of 20 protein amino acids, lysine, methionine and tryptophan strongly interfere with O. minor early development. Field research confirmed their inhibitory effect but revealed that methionine was more effective than lysine and tryptophan, and that two successive methionine applications at 308 and 543 growing degree days inhibited O. minor emergence in red clover up to 67%. We investigated additional effects with potential to influence the practical use of amino acids against broomrape weeds, whether the herbicidal effect may be reversible by other amino acids exuded by host plants or may be amplified by inducing host resistance barriers against O. minor penetration. This paper suggests that amino acids may have the potential to be integrated into biorational programs of broomrape management. PMID:28588599

Epidemiological review of human and animal fascioliasis in Egypt.

PubMed

Soliman, Maha F M

2008-06-01

One of the neglected food-borne-diseases in the international public health arena is fascioliasis. It is a serious infectious parasitic disease infecting humans and animals worldwide and tops all the zoonotic helminthes. Human cases are being increasingly reported from Europe, the Americas, Oceania, Africa and Asia. Hence, human fascioliasis is considered now as a zoonosis of major global and regional importance. In Egypt, animal and human fascioliasis is an endemic clinical and epidemiological health problem. Doubtless, understanding the epidemiology of the parasitic diseases and factors affecting their incidence provides the foundation upon which effective prevention and control programs should be established. This article reviews the history, life cycles, transmission, incidence, geographical distribution, and environmental and human determinants that contribute to the epidemiological picture of fascioliasis with special reference to Egypt.

Association between parasitic infections and tuberculin skin test results in refugees.

PubMed

Watts, Nathaniel S; Mizinduko, Mucho M; Barnett, Elizabeth D; White, Laura F; Hochberg, Natasha S

Parasitic infections are known to modulate the immune response necessary for controlling Mycobacterium tuberculosis infection. We sought to investigate species-specific effects of parasite infection on M. tuberculosis infection. As part of the Refugee Health Assessment Program, stool examinations and tuberculin skin testing were performed on refugees seen at Boston Medical Center between 1995 and 2012. Tuberculin skin test (TST) and stool examination data were collected for 6669 refugees; 3349 (50.2%) were TST positive (≥10 mm). Among TST-positive subjects, 176 (5.3%) had helminth infections and 1149 (34.3%) protozoa. After adjusting for sex, age, and country of origin, helminth and protozoan infections were not associated with TST-positivity. When species-specific effects were examined, subjects infected with Trichuris trichiura and Giardia lamblia had reduced odds of TST-positivity (adjusted OR [aOR] 0.65 [95%CI 0.44-0.96; p = 0.03] and aOR 0.79 [95%CI 0.65-0.95, p = 0.01], respectively). Our findings suggest that T. trichiura and G. lamblia may provide protection against M. tuberculosis infection. This study adds to a growing body of literature suggesting that immune response modulation and susceptibility to M. tuberculosis infection is parasite species-dependent. Copyright © 2017 Elsevier Ltd. All rights reserved.

Zoonotic diseases: health aspects of Canadian geese.

PubMed

Dieter, R A; Dieter, R S; Dieter, R A; Gulliver, G

2001-11-01

Review zoonotic diseases associated with Canadian geese. Review article: A review of the multiple physical, microbiologic and safety concerns, and methods used in controlling this potential problem. Over the last decade the Canadian goose population (protected by international treaties and protection acts) has increased rapidly such that in many cities they have become a pest rather than an admired wild bird. Their increasing numbers have caused a number of potential healthcare concerns including: physical, bacterial, parasitic, allergic and viral potential problems. The Canadian goose fecal droppings of one per minute have caused falls and the flying geese have caused air traffic accidents. Bacterial concerns, including botulism, salmonella and E. coli have all been reviewed and presented concerns. The viral Newcastle disease may be detected with hemagglutination studies and the Giardia psittaci parasites have been repeatedly found in their droppings. The Cryptosporidium parvum oocytes have been present on stool study. Definite links to human infectious diseases have been difficult to prove. Revision of the current laws and new control programs must be developed.

[Evaluation on intervention measures of comprehensive control for parasitic diseases in demonstration plot of Xiangyun County].

PubMed

Wen-Juan, Li; Shao-Rong, Chen; Yan-Hong, Li; Wen, Fang; Chun-Rong, Ke; Li-Bo, Wang

2011-10-01

To evaluate the effect of comprehensive intervention measures to control and prevent parasitic diseases in the demonstration plot of Xiangyun County, so as to provide the evidence for establishing appropriate measures of parasitic diseases control and prevention. The baseline data of soil-transmitted nematode infections were obtained in 2006. A series of intervention measures, including health education, deworming, drinking water improvement,latrine improvement, and environment reconstruction, were performed for three years and the effect of the comprehensive intervention measures was evaluated by the national expert group in 2009. The awareness rate of parasitic disease knowledge of residents in 2009 (86.96%) was significantly higher than that in 2006 (35.20%) (Chi2 = 122.95, P < 0.01). The passing rate of resident health behavior in 2009 (97.10%) was significantly higher than that in 2006 (48.00%) (Chi2 = 122.95, P < 0.01). The general infection rate of parasites in 2009 (2.47%) was significantly lower than that in 2006 (19.14%) (Chi2 = 162.88, P < 0.01). Of soil-transmitted nematode infections, the infection rates of Ascaris lumbricoides in both 2006 and 2009 were the highest and the rates were 18.74% and 2.08%, respectively. In the demonstration plots for parasitic diseases control and prevention of Xiangyun County, the effect of the comprehensive intervention measures which take health education as the forerunner and give priority to control source of parasite infection is remarkable. The measures implemented can achieve the purpose to reduce the infection rates of parasites and improve human health.

Reduced neophobia: a potential mechanism explaining the emergence of self-medicative behavior in sheep.

PubMed

Egea, A Vanina; Hall, Jeffery O; Miller, James; Spackman, Casey; Villalba, Juan J

2014-08-01

Gastrointestinal helminths challenge ruminants in ways that reduce their fitness. In turn, ruminants have evolved physiological and behavioral adaptations that counteract this challenge. For instance, emerging behavioral evidence suggests that ruminants self-select medicinal compounds and foods that reduce parasitic burdens. However, the mechanism/s leading to self-medicative behaviors in sick animals is still unknown. We hypothesized that when homeostasis is disturbed by a parasitic infection, consumers should respond by increasing the acceptability of novel foods relative to healthy individuals. Three groups of lambs (N=10) were dosed with 0 (Control-C), 5000 (Medium-M) and 15000 (High-H) L3 stage larvae of Haemonchus contortus. When parasites had reached the adult stage, all animals were offered novel foods and flavors in pens and then novel forages at pasture. Ingestive responses by parasitized lambs were different from non-parasitized Control animals and they varied with the type of food and flavor on offer. Parasitized lambs consumed initially more novel beet pulp and less novel beet pulp mixed with tannins than Control lambs, but the pattern reversed after 9d of exposure to these foods. Parasitized lambs ingested more novel umami-flavored food and less novel bitter-flavored food than Control lambs. When offered choices of novel unflavored and bitter-flavored foods or different forage species to graze, parasitized lambs selected a more diverse array of foods than Control lambs. Reductions in food neophobia or selection of a more diverse diet may enhance the likelihood of sick herbivores encountering novel medicinal plants and nutritious forages that contribute to restore health. Published by Elsevier Inc.

Human onchocerciasis in Brazil: an overview.

PubMed

Shelley, Anthony J

2002-01-01

Human onchocerciasis was recently discovered in Brazil among Yanomámi Indians living along the border region with Venezuela in the States of Amazonas and Roraima. The article reports on the history of the disease's discovery, its distribution, and incrimination of vector simuliid species. The literature that has been generated on the parasite, its vectors, and control of the disease is critically analyzed as well as the organization of epidemiological surveys and the control program developed by the Brazilian government and an international agency. Suggestions for future work are made.

Frontiers of parasitology research in the People's Republic of China: infection, diagnosis, protection and surveillance

PubMed Central

2012-01-01

Control and eventual elimination of human parasitic diseases in the People's Republic of China (P.R. China) requires novel approaches, particularly in the areas of diagnostics, mathematical modelling, monitoring, evaluation, surveillance and public health response. A comprehensive effort, involving the collaboration of 188 scientists (>85% from P.R. China) from 48 different institutions and universities (80% from P.R. China), covers this collection of 29 articles published in Parasites & Vectors. The research mainly stems from a research project entitled “Surveillance and diagnostic tools for major parasitic diseases in P.R. China” (grant no. 2008ZX10004-011) and highlights the frontiers of research in parasitology. The majority of articles in this thematic series deals with the most important parasitic diseases in P.R. China, emphasizing Schistosoma japonicum, Plasmodium vivax and Clonorchis sinensis plus some parasites of emerging importance such as Angiostrongylus cantonensis. Significant achievements have been made through the collaborative research programme in the following three fields: (i) development of strategies for the national control programme; (ii) updating the surveillance data of parasitic infections both in human and animals; and (iii) improvement of existing, and development of novel, diagnostic tools to detect parasitic infections. The progress is considerable and warrants broad validation efforts. Combined with the development of improved tools for diagnosis and surveillance, integrated and multi-pronged control strategies should now pave the way for elimination of parasitic diseases in P.R. China. Experiences and lessons learned can stimulate control and elimination efforts of parasitic diseases in other parts of the world. PMID:23036110

Intestinal parasites and genotypes of Giardia intestinalis in school children from Berisso, Argentina.

PubMed

Molina, Nora; Pezzani, Betina; Ciarmela, Maria; Orden, Alicia; Rosa, Diana; Apezteguía, Maria; Basualdo, Juan; Minvielle, Marta

2011-07-27

Intestinal parasitic infections have been reported in different regions of Argentina. Giardia intestinalis is recognized as "the national parasite". The aim of this work was to determine the prevalence of both intestinal parasites and G. intestinalis genotypes, as well as to analyze the clinical and epidemiological characteristics in schoolchildren from a suburban community. Serial coproparasitological analysis and perianal swab method were performed in 244 schoolchildren. Demographic, sociocultural and environmental variables were registered. The presence of signs/symptoms and risk behaviours were also recorded. Stools with G. intestinalis were selected for genotyping. Out of 244 schoolchildren, 179/244 (73.4%) were infected with intestinal parasites. The presence of intestinal parasitosis was associated only with house flooding. Multivariate analysis identified that use of a latrine is significantly correlated with G. intestinalis and age six to 11 years with E. vermicularis. Signs and symptoms were recorded in 62% of infected children and in 57.9% of those not infected. Genomic amplification was revealed that 65.7% (46/70) of Giardia positive samples corresponded to genotype B, 31.4% (22/70) to genotype AII, and two samples (2.8%) had mixed infection (AII + B). This study shows a high percentage of infected children living in a suburban community in poor sanitary conditions, and not visiting the doctor in spite of evident signs and symptoms associated a digestive pathology. This situation supports the need for continuing the development of community programs allowing the improvement of quality of life and control of parasitosis in deprived populations.

Linking parasite populations in hosts to parasite populations in space through Taylor's law and the negative binomial distribution

PubMed Central

Poulin, Robert; Lagrue, Clément

2017-01-01

The spatial distribution of individuals of any species is a basic concern of ecology. The spatial distribution of parasites matters to control and conservation of parasites that affect human and nonhuman populations. This paper develops a quantitative theory to predict the spatial distribution of parasites based on the distribution of parasites in hosts and the spatial distribution of hosts. Four models are tested against observations of metazoan hosts and their parasites in littoral zones of four lakes in Otago, New Zealand. These models differ in two dichotomous assumptions, constituting a 2 × 2 theoretical design. One assumption specifies whether the variance function of the number of parasites per host individual is described by Taylor's law (TL) or the negative binomial distribution (NBD). The other assumption specifies whether the numbers of parasite individuals within each host in a square meter of habitat are independent or perfectly correlated among host individuals. We find empirically that the variance–mean relationship of the numbers of parasites per square meter is very well described by TL but is not well described by NBD. Two models that posit perfect correlation of the parasite loads of hosts in a square meter of habitat approximate observations much better than two models that posit independence of parasite loads of hosts in a square meter, regardless of whether the variance–mean relationship of parasites per host individual obeys TL or NBD. We infer that high local interhost correlations in parasite load strongly influence the spatial distribution of parasites. Local hotspots could influence control and conservation of parasites. PMID:27994156

Control of toxic marine dinoflagellate blooms by serial parasitic killers.

PubMed

Chambouvet, Aurelie; Morin, Pascal; Marie, Dominique; Guillou, Laure

2008-11-21

The marine dinoflagellates commonly responsible for toxic red tides are parasitized by other dinoflagellate species. Using culture-independent environmental ribosomal RNA sequences and fluorescence markers, we identified host-specific infections among several species. Each parasitoid produces 60 to 400 offspring, leading to extraordinarily rapid control of the host's population. During 3 consecutive years of observation in a natural estuary, all dinoflagellates observed were chronically infected, and a given host species was infected by a single genetically distinct parasite year after year. Our observations in natural ecosystems suggest that although bloom-forming dinoflagellates may escape control by grazing organisms, they eventually succumb to parasite attack.

Ecological multiplex interactions determine the role of species for parasite spread amplification

PubMed Central

Stella, Massimo; Selakovic, Sanja; Antonioni, Alberto

2018-01-01

Despite their potential interplay, multiple routes of many disease transmissions are often investigated separately. As a unifying framework for understanding parasite spread through interdependent transmission paths, we present the ‘ecomultiplex’ model, where the multiple transmission paths among a diverse community of interacting hosts are represented as a spatially explicit multiplex network. We adopt this framework for designing and testing potential control strategies for Trypanosoma cruzi spread in two empirical host communities. We show that the ecomultiplex model is an efficient and low data-demanding method to identify which species enhances parasite spread and should thus be a target for control strategies. We also find that the interplay between predator-prey and host-parasite interactions leads to a phenomenon of parasite amplification, in which top predators facilitate T. cruzi spread, offering a mechanistic interpretation of previous empirical findings. Our approach can provide novel insights in understanding and controlling parasite spreading in real-world complex systems. PMID:29683427

Sensing parasites: Proteomic and advanced bio-detection alternatives.

PubMed

Sánchez-Ovejero, Carlos; Benito-Lopez, Fernando; Díez, Paula; Casulli, Adriano; Siles-Lucas, Mar; Fuentes, Manuel; Manzano-Román, Raúl

2016-03-16

Parasitic diseases have a great impact in human and animal health. The gold standard for the diagnosis of the majority of parasitic infections is still conventional microscopy, which presents important limitations in terms of sensitivity and specificity and commonly requires highly trained technicians. More accurate molecular-based diagnostic tools are needed for the implementation of early detection, effective treatments and massive screenings with high-throughput capacities. In this respect, sensitive and affordable devices could greatly impact on sustainable control programmes which exist against parasitic diseases, especially in low income settings. Proteomics and nanotechnology approaches are valuable tools for sensing pathogens and host alteration signatures within microfluidic detection platforms. These new devices might provide novel solutions to fight parasitic diseases. Newly described specific parasite derived products with immune-modulatory properties have been postulated as the best candidates for the early and accurate detection of parasitic infections as well as for the blockage of parasite development. This review provides the most recent methodological and technological advances with great potential for bio-sensing parasites in their hosts, showing the newest opportunities offered by modern "-omics" and platforms for parasite detection and control. Copyright © 2016 Elsevier B.V. All rights reserved.

microRNAs in parasites and parasite infection

PubMed Central

Zheng, Yadong; Cai, Xuepeng; Bradley, Janette E.

2013-01-01

miRNAs, a subclass of small regulatory RNAs, are present from ancient unicellular protozoans to parasitic helminths and parasitic arthropods. The miRNA-silencing mechanism appears, however, to be absent in a number of protozoan parasites. Protozoan miRNAs and components of their silencing machinery possess features different from other eukaryotes, providing some clues on the evolution of the RNA-induced silencing machinery. miRNA functions possibly associate with neoblast biology, development, physiology, infection and immunity of parasites. Parasite infection can alter host miRNA expression that can favor both parasite clearance and infection. miRNA pathways are, thus, a potential target for the therapeutic control of parasitic diseases. PMID:23392243

Evidence of a species complex within the food-borne trematode Opisthorchis viverrini and possible co-evolution with their first intermediate hosts.

PubMed

Saijuntha, Weerachai; Sithithaworn, Paiboon; Wongkham, Sopit; Laha, Thewarach; Pipitgool, Vichit; Tesana, Smarn; Chilton, Neil B; Petney, Trevor N; Andrews, Ross H

2007-05-01

The food-borne trematodes, Opisthorchis viverrini, O. felineus and Clonorchis sinensis, have long been recognized as the cause of major human health problems, with an estimated 40 million infected persons. Of the three species of liver fluke, only O. viverrini is classified as a type 1 carcinogen because of its role as an initiator of chronic inflammation and the subsequent development of cholangiocarcinoma. At present, there are no techniques for the early diagnosis of cholangiocarcinoma and it is fatal for most patients. There is considerable variation in parasite prevalence and disease presentation in different geographical areas, the latter of which may be associated with genetic differences among parasites. In the present study, multilocus enzyme electrophoresis was used to provide a comprehensive genetic characterization of O. viverrini from different geographical localities in Thailand and the Peoples' Democratic Republic of Laos. Parasites from different localities were compared genetically at 32 enzyme loci. The results of the genetic analyses are sufficient to reject the null hypothesis that O. viverrini represents a single species. Therefore, O. viverrini consists of at least two genetically distinct, yet morphologically similar (i.e. cryptic) species. Moreover, there was also separation of the different populations of snails (i.e. the first intermediate hosts) into two distinct genetic groups that corresponded with the delineation of O. viverrini into two species. This suggests that there may be a history of co-evolution in this host-parasite lineage. Additionally, five distinct genetic groups of parasites were detected, each of which occurred within a different and independent river wetland system. Our findings have major implications for the implementation of effective control and surveillance programs targeted to these medically important food-borne parasites.

A Dynamic Stress Model Explains the Delayed Drug Effect in Artemisinin Treatment of Plasmodium falciparum

PubMed Central

Cao, Pengxing; Klonis, Nectarios; Zaloumis, Sophie; Dogovski, Con; Xie, Stanley C.; Saralamba, Sompob; White, Lisa J.; Fowkes, Freya J. I.; Tilley, Leann; Simpson, Julie A.

2017-01-01

ABSTRACT Artemisinin resistance constitutes a major threat to the continued success of control programs for malaria, particularly in light of developing resistance to partner drugs. Improving our understanding of how artemisinin-based drugs act and how resistance manifests is essential for the optimization of dosing regimens and the development of strategies to prolong the life span of current first-line treatment options. Recent short-drug-pulse in vitro experiments have shown that the parasite killing rate depends not only on drug concentration but also the exposure time, challenging the standard pharmacokinetic-pharmacodynamic (PK-PD) paradigm in which the killing rate depends only on drug concentration. Here, we introduce a dynamic stress model of parasite killing and show through application to 3D7 laboratory strain viability data that the inclusion of a time-dependent parasite stress response dramatically improves the model's explanatory power compared to that of a traditional PK-PD model. Our model demonstrates that the previously reported hypersensitivity of early-ring-stage parasites of the 3D7 strain to dihydroartemisinin compared to other parasite stages is due primarily to a faster development of stress rather than a higher maximum achievable killing rate. We also perform in vivo simulations using the dynamic stress model and demonstrate that the complex temporal features of artemisinin action observed in vitro have a significant impact on predictions for in vivo parasite clearance. Given the important role that PK-PD models play in the design of clinical trials for the evaluation of alternative drug dosing regimens, our novel model will contribute to the further development and improvement of antimalarial therapies. PMID:28993326

Transcriptionally Driven DNA Replication Program of the Human Parasite Leishmania major.

PubMed

Lombraña, Rodrigo; Álvarez, Alba; Fernández-Justel, José Miguel; Almeida, Ricardo; Poza-Carrión, César; Gomes, Fábia; Calzada, Arturo; Requena, José María; Gómez, María

2016-08-09

Faithful inheritance of eukaryotic genomes requires the orchestrated activation of multiple DNA replication origins (ORIs). Although origin firing is mechanistically conserved, how origins are specified and selected for activation varies across different model systems. Here, we provide a complete analysis of the nucleosomal landscape and replication program of the human parasite Leishmania major, building on a better evolutionary understanding of replication organization in Eukarya. We found that active transcription is a driving force for the nucleosomal organization of the L. major genome and that both the spatial and the temporal program of DNA replication can be explained as associated to RNA polymerase kinetics. This simple scenario likely provides flexibility and robustness to deal with the environmental changes that impose alterations in the genetic programs during parasitic life cycle stages. Our findings also suggest that coupling replication initiation to transcription elongation could be an ancient solution used by eukaryotic cells for origin maintenance. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

Toxoplasma gondii as a parasite in food: analysis and control

USDA-ARS?s Scientific Manuscript database

Toxoplasmosis, caused by Toxoplasma gondii, is one of the most common parasitic infections of humans and other warmblooded animals. Nearly one third of humans have been exposed to the parasite. Congenital infection occurs when a woman becomes infected during pregnancy and transmits the parasite to t...

Simulated selection responses for breeding programs including resistance and resilience to parasites in Creole goats.

PubMed

Gunia, M; Phocas, F; Gourdine, J-L; Bijma, P; Mandonnet, N

2013-02-01

The Creole goat is a local breed used for meat production in Guadeloupe (French West Indies). As in other tropical countries, improvement of parasite resistance is needed. In this study, we compared predicted selection responses for alternative breeding programs with or without parasite resistance and resilience traits. The overall breeding goal included traits for production, reproduction, and parasite resilience and resistance to ensure a balanced selection outcome. The production traits were BW and dressing percentage (DP). The reproduction trait was fertility (FER), which was the number of doe kiddings per mating. The resistance trait was worm fecal egg count (FEC), which is a measurement of the number of gastro-intestinal parasite eggs found in the feces. The resilience trait was the packed cell volume (PCV), which is a measurement of the volume of red blood cells in the blood. Dressing percentage, BW, and FEC were measured at 11 mo of age, which is the mating or selling age. Fertility and PCV were measured on females at each kidding period. The breeding program accounting for the overall breeding goal and a selection index including all traits gave annual selection responses of 800 g for BW, 3.75% for FER, 0.08% for DP, -0.005 ln(eggs/g) for FEC, and 0.28% for PCV. The expected selection responses for BW and DP in this breeding program were reduced by 2% and 6%, respectively, compared with a breeding program not accounting for FEC and PCV. The overall breeding program, proposed for the Creole breed, offers the best breeding strategy in terms of expected selection responses, making it possible to improve all traits together. It offers a good balance between production and adaptation traits and may present some interest for the selection of other goat breeds in the tropics.

A research agenda for helminth diseases of humans: basic research and enabling technologies to support control and elimination of helminthiases.

PubMed

Lustigman, Sara; Geldhof, Peter; Grant, Warwick N; Osei-Atweneboana, Mike Y; Sripa, Banchob; Basáñez, María-Gloria

2012-01-01

Successful and sustainable intervention against human helminthiases depends on optimal utilisation of available control measures and development of new tools and strategies, as well as an understanding of the evolutionary implications of prolonged intervention on parasite populations and those of their hosts and vectors. This will depend largely on updated knowledge of relevant and fundamental parasite biology. There is a need, therefore, to exploit and apply new knowledge and techniques in order to make significant and novel gains in combating helminthiases and supporting the sustainability of current and successful mass drug administration (MDA) programmes. Among the fields of basic research that are likely to yield improved control tools, the Disease Reference Group on Helminth Infections (DRG4) has identified four broad areas that stand out as central to the development of the next generation of helminth control measures: 1) parasite genetics, genomics, and functional genomics; 2) parasite immunology; 3) (vertebrate) host-parasite interactions and immunopathology; and 4) (invertebrate) host-parasite interactions and transmission biology. The DRG4 was established in 2009 by the Special Programme for Research and Training in Tropical Diseases (TDR). The Group was given the mandate to undertake a comprehensive review of recent advances in helminthiases research in order to identify notable gaps and highlight priority areas. This paper summarises recent advances and discusses challenges in the investigation of the fundamental biology of those helminth parasites under the DRG4 Group's remit according to the identified priorities, and presents a research and development agenda for basic parasite research and enabling technologies that will help support control and elimination efforts against human helminthiases.

Methods to Increase the Sensitivity of High Resolution Melting Single Nucleotide Polymorphism Genotyping in Malaria.

PubMed

Daniels, Rachel; Hamilton, Elizabeth J; Durfee, Katelyn; Ndiaye, Daouda; Wirth, Dyann F; Hartl, Daniel L; Volkman, Sarah K

2015-11-10

Despite decades of eradication efforts, malaria remains a global burden. Recent renewed interest in regional elimination and global eradication has been accompanied by increased genomic information about Plasmodium parasite species responsible for malaria, including characteristics of geographical populations as well as variations associated with reduced susceptibility to anti-malarial drugs. One common genetic variation, single-nucleotide polymorphisms (SNPs), offers attractive targets for parasite genotyping. These markers are useful not only for tracking drug resistance markers but also for tracking parasite populations using markers not under drug or other selective pressures. SNP genotyping methods offer the ability to track drug resistance as well as to fingerprint individual parasites for population surveillance, particularly in response to malaria control efforts in regions nearing elimination status. While informative SNPs have been identified that are agnostic to specific genotyping technologies, high-resolution melting (HRM) analysis is particularly suited to field-based studies. Compared to standard fluorescent-probe based methods that require individual SNPs in a single labeled probe and offer at best 10% sensitivity to detect SNPs in samples that contain multiple genomes (polygenomic), HRM offers 2-5% sensitivity. Modifications to HRM, such as blocked probes and asymmetric primer concentrations as well as optimization of amplification annealing temperatures to bias PCR towards amplification of the minor allele, further increase the sensitivity of HRM. While the sensitivity improvement depends on the specific assay, we have increased detection sensitivities to less than 1% of the minor allele. In regions approaching malaria eradication, early detection of emerging or imported drug resistance is essential for prompt response. Similarly, the ability to detect polygenomic infections and differentiate imported parasite types from cryptic local reservoirs can inform control programs. This manuscript describes modifications to high resolution melting technology that further increase its sensitivity to identify polygenomic infections in patient samples.

Stage-Specific Transcriptome and Proteome Analyses of the Filarial Parasite Onchocerca volvulus and Its Wolbachia Endosymbiont

PubMed Central

Bennuru, Sasisekhar; Cotton, James A.; Ribeiro, Jose M. C.; Grote, Alexandra; Harsha, Bhavana; Holroyd, Nancy; Mhashilkar, Amruta; Molina, Douglas M.; Randall, Arlo Z.; Shandling, Adam D.; Unnasch, Thomas R.; Ghedin, Elodie; Berriman, Matthew

2016-01-01

ABSTRACT Onchocerciasis (river blindness) is a neglected tropical disease that has been successfully targeted by mass drug treatment programs in the Americas and small parts of Africa. Achieving the long-term goal of elimination of onchocerciasis, however, requires additional tools, including drugs, vaccines, and biomarkers of infection. Here, we describe the transcriptome and proteome profiles of the major vector and the human host stages (L1, L2, L3, molting L3, L4, adult male, and adult female) of Onchocerca volvulus along with the proteome of each parasitic stage and of its Wolbachia endosymbiont (wOv). In so doing, we have identified stage-specific pathways important to the parasite’s adaptation to its human host during its early development. Further, we generated a protein array that, when screened with well-characterized human samples, identified novel diagnostic biomarkers of O. volvulus infection and new potential vaccine candidates. This immunomic approach not only demonstrates the power of this postgenomic discovery platform but also provides additional tools for onchocerciasis control programs. PMID:27881553

Role of Chemokines and Trafficking of Immune Cells in Parasitic Infections

PubMed Central

McGovern, Kathryn E.; Wilson, Emma H.

2014-01-01

Parasites are diverse eukaryotic pathogens that can have complex life cycles. Their clearance, or control within a mammalian host requires the coordinated effort of the immune system. The cell types recruited to areas of infection can combat the disease, promote parasite replication and survival, or contribute to disease pathology. Location and timing of cell recruitment can be crucial. In this review, we explore the role chemokines play in orchestrating and balancing the immune response to achieve optimal control of parasite replication without promoting pathology. PMID:25383073

Rationale for the Coadministration of Albendazole and Ivermectin to Humans for Malaria Parasite Transmission Control

DTIC Science & Technology

2014-07-28

programs and supported by global public health funding agencies. Albendazole belongs to the class of benzimidazole anthel- mintics that are active against...blood-stage P. falciparum in vitro83,84 and P. berghei in vivo85,86 but not at human-relevant concentrations. The benzimidazoles are microtubule...cycles at which benzimidazoles may inhibit microtubule assem- bly, including micro- and macrogametocytogenisis, microga- mete exflaggelation, and the

Natural enemies of Atta vollenweideri (Hymenoptera: Formicidae) leaf-cutter ants negatively affected by synthetic pesticides, chlorpyrifos and fipronil.

PubMed

Guillade, Andrea C; Folgarait, Patricia J

2014-02-01

In southern South America, Ada vollenweideri Forel (Hymenoptera: Formicidae) is a significant pest of several crops and forestry, also considered to reduce the carrying capacity of pastures. The most usual control method used in Latin America is the application of synthetic pesticides, mainly chlorpyrifos and fipronil. However, no studies have assessed the effects of these agrochemicals on natural enemies of ants. We aimed to evaluate the efficiency of these pesticides on leaf-cutter ants' control and to test their effect on phorid fly parasitoids. Chlorpyrifos failed to exert complete control over ant colonies in the field and was gravely detrimental to specific parasitoids, reducing their percentage of parasitism, pupal survivorship, and adult longevity. Fipronil, however, exerted complete control over the treated colonies. Laboratory tests using both pesticides, either on ants from foraging trails or on pupariae, showed that chlorpyrifos and fipronil decreased larval and pupal survivorship, as well as adult longevity of parasitoids, in comparison to controls. In conclusion, these pesticides will likely affect parasitoids with regard to their reproductive capacity, leading to the decreased levels of natural parasitism observed in the field after treatments. We discuss why neither pesticide should be taken into account for integrated pest management programs.

Host-Parasite Interactions from the Inside: Plant Reproductive Ontogeny Drives Specialization in Parasitic Insects

PubMed Central

Boivin, Thomas; Gidoin, Cindy; von Aderkas, Patrick; Safrana, Jonathan; Candau, Jean-Noël; Chalon, Alain; Sondo, Marion; El Maâtaoui, Mohamed

2015-01-01

Host plant interactions are likely key drivers of evolutionary processes involved in the diversification of phytophagous insects. Granivory has received substantial attention for its crucial role in shaping the interaction between plants and their seed parasites, but fine-scale mechanisms explaining the role of host plant reproductive biology on specialization of seed parasites remain poorly described. In a comparative approach using plant histological techniques, we tested the hypotheses that different seed parasite species synchronize their life cycles to specific stages in seed development, and that the stage they target depends on major differences in seed development programs. In a pinaceous system, seed storage products are initiated before ovule fertilization and the wasps target the ovule’s nucellus during megagametogenesis, a stage at which larvae may benefit from the by-products derived from both secreting cells and dying nucellar cells. In a cupressaceous system, oviposition activity peaks later, during embryogenesis, and the wasps target the ovule’s megagametophyte where larvae may benefit from cell disintegration during embryogenesis. Our cytohistological approach shows for the first time how, despite divergent oviposition targets, different parasite species share a common strategy that consists of first competing for nutrients with developing plant structures, and then consuming these developed structures to complete their development. Our results support the prediction that seed developmental program is an axis for specialization in seed parasites, and that it could be an important parameter in models of their ecological and taxonomic divergence. This study provides the basis for further investigating the possibility of the link between plant ontogeny and pre-dispersal seed parasitism. PMID:26441311

Host-Parasite Interactions from the Inside: Plant Reproductive Ontogeny Drives Specialization in Parasitic Insects.

PubMed

Boivin, Thomas; Gidoin, Cindy; von Aderkas, Patrick; Safrana, Jonathan; Candau, Jean-Noël; Chalon, Alain; Sondo, Marion; El Maâtaoui, Mohamed

2015-01-01

Host plant interactions are likely key drivers of evolutionary processes involved in the diversification of phytophagous insects. Granivory has received substantial attention for its crucial role in shaping the interaction between plants and their seed parasites, but fine-scale mechanisms explaining the role of host plant reproductive biology on specialization of seed parasites remain poorly described. In a comparative approach using plant histological techniques, we tested the hypotheses that different seed parasite species synchronize their life cycles to specific stages in seed development, and that the stage they target depends on major differences in seed development programs. In a pinaceous system, seed storage products are initiated before ovule fertilization and the wasps target the ovule's nucellus during megagametogenesis, a stage at which larvae may benefit from the by-products derived from both secreting cells and dying nucellar cells. In a cupressaceous system, oviposition activity peaks later, during embryogenesis, and the wasps target the ovule's megagametophyte where larvae may benefit from cell disintegration during embryogenesis. Our cytohistological approach shows for the first time how, despite divergent oviposition targets, different parasite species share a common strategy that consists of first competing for nutrients with developing plant structures, and then consuming these developed structures to complete their development. Our results support the prediction that seed developmental program is an axis for specialization in seed parasites, and that it could be an important parameter in models of their ecological and taxonomic divergence. This study provides the basis for further investigating the possibility of the link between plant ontogeny and pre-dispersal seed parasitism.

Impacts of Parasites in Early Life: Contrasting Effects on Juvenile Growth for Different Family Members

PubMed Central

Reed, Thomas E.; Daunt, Francis; Kiploks, Adam J.; Burthe, Sarah J.; Granroth-Wilding, Hanna M. V.; Takahashi, Emi A.; Newell, Mark; Wanless, Sarah; Cunningham, Emma J. A.

2012-01-01

Parasitism experienced early in ontogeny can have a major impact on host growth, development and future fitness, but whether siblings are affected equally by parasitism is poorly understood. In birds, hatching asynchrony induced by hormonal or behavioural mechanisms largely under parental control might predispose young to respond to infection in different ways. Here we show that parasites can have different consequences for offspring depending on their position in the family hierarchy. We experimentally treated European Shag (Phalacrocorax aristoteli) nestlings with the broad-spectrum anti-parasite drug ivermectin and compared their growth rates with nestlings from control broods. Average growth rates measured over the period of linear growth (10 days to 30 days of age) and survival did not differ for nestlings from treated and control broods. However, when considering individuals within broods, parasite treatment reversed the patterns of growth for individual family members: last-hatched nestlings grew significantly slower than their siblings in control nests but grew faster in treated nests. This was at the expense of their earlier-hatched brood-mates, who showed an overall growth rate reduction relative to last-hatched nestlings in treated nests. These results highlight the importance of exploring individual variation in the costs of infection and suggest that parasites could be a key factor modulating within-family dynamics, sibling competition and developmental trajectories from an early age. PMID:22384190

Strategic evaluation of vaccine candidate antigens for the prevention of Visceral Leishmaniasis.

PubMed

Duthie, Malcolm S; Favila, Michelle; Hofmeyer, Kimberley A; Tutterrow, Yeung L; Reed, Steven J; Laurance, John D; Picone, Alessandro; Guderian, Jeffrey; Bailor, H Remy; Vallur, Aarthy C; Liang, Hong; Mohamath, Raodoh; Vergara, Julie; Howard, Randall F; Coler, Rhea N; Reed, Steven G

2016-05-27

Infection with Leishmania parasites results in a range of clinical manifestations and outcomes, the most severe of which is visceral leishmaniasis (VL). Vaccination will likely provide the most effective long-term control strategy, as the large number of vectors and potential infectious reservoirs renders sustained interruption of Leishmania parasite transmission extremely difficult. Selection of the best vaccine is complicated because, although several vaccine antigen candidates have been proposed, they have emerged following production in different platforms. To consolidate the information that has been generated into a single vaccine platform, we expressed seven candidates as recombinant proteins in E. coli. After verifying that each recombinant protein could be recognized by VL patients, we evaluated their protective efficacy against experimental L. donovani infection of mice. Administration in formulation with the Th1-potentiating adjuvant GLA-SE indicated that each antigen could elicit antigen-specific Th1 responses that were protective. Considering the ability to reduce parasite burden along with additional factors such as sequence identity across Leishmania species, we then generated a chimeric fusion protein comprising a combination of the 8E, p21 and SMT proteins. This E. coli -expressed fusion protein was also demonstrated to protect against L. donovani infection. These data indicate a novel recombinant vaccine antigen with the potential for use in VL control programs. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

PCR-Based Molecular Characterization of Toxocara spp. Using Feces of Stray Cats: A Study from Southwest Iran

PubMed Central

Tavalla, Mahdi; Abdizadeh, Rahman; Hashemitabar, Mahmoud

2013-01-01

Feces of stray cat are potential sources of gastrointestinal parasites and play a crucial role in spreading and transmitting parasite eggs, larvae, and oocysts through contamination of soil, food, or water. In this study, we investigated the prevalence of Toxocara spp. infection in stray cats in Ahvaz city, southwest Iran. Eggs of Toxocara spp. in feces of stray cats were detected by the sucrose flotation method, and identification was conducted by polymerase chain reaction (PCR) and DNA sequencing. Of the 140 fecal samples that were randomly collected from public environments during the months of January to May 2012, 45% were found to harbour Toxocara spp. eggs. The highest prevalence of Toxocara spp. eggs was found in the central area of Ahvaz city (28.6%). T. canis eggs were found in 4 (6.34%) of the 63 positive samples. Stray cats are found in parks, playgrounds, and other public places and may be a potential contamination risk. Identification of Toxocara spp. using molecular methods is sufficiently sensitive to detect low levels of parasites and identify the different Toxocara spp. in feces. The relatively high prevalence of Toxocara spp. infection may continue to increase due to lack of effective environmental hygiene control in Iran. Consequently, there is a need to plan adequate programs to detect, identify, and control this infection as well as stray cats in the region. PMID:23755213

PCR-based molecular characterization of Toxocara spp. using feces of stray cats: a study from Southwest Iran.

PubMed

Khademvatan, Shahram; Rahim, Fakher; Tavalla, Mahdi; Abdizadeh, Rahman; Hashemitabar, Mahmoud

2013-01-01

Feces of stray cat are potential sources of gastrointestinal parasites and play a crucial role in spreading and transmitting parasite eggs, larvae, and oocysts through contamination of soil, food, or water. In this study, we investigated the prevalence of Toxocara spp. infection in stray cats in Ahvaz city, southwest Iran. Eggs of Toxocara spp. in feces of stray cats were detected by the sucrose flotation method, and identification was conducted by polymerase chain reaction (PCR) and DNA sequencing. Of the 140 fecal samples that were randomly collected from public environments during the months of January to May 2012, 45% were found to harbour Toxocara spp. eggs. The highest prevalence of Toxocara spp. eggs was found in the central area of Ahvaz city (28.6%). T. canis eggs were found in 4 (6.34%) of the 63 positive samples. Stray cats are found in parks, playgrounds, and other public places and may be a potential contamination risk. Identification of Toxocara spp. using molecular methods is sufficiently sensitive to detect low levels of parasites and identify the different Toxocara spp. in feces. The relatively high prevalence of Toxocara spp. infection may continue to increase due to lack of effective environmental hygiene control in Iran. Consequently, there is a need to plan adequate programs to detect, identify, and control this infection as well as stray cats in the region.

Resistance of a rodent malaria parasite to a thymidylate synthase inhibitor induces an apoptotic parasite death and imposes a huge cost of fitness.

PubMed

Muregi, Francis W; Ohta, Isao; Masato, Uchijima; Kino, Hideto; Ishih, Akira

2011-01-01

The greatest impediment to effective malaria control is drug resistance in Plasmodium falciparum, and thus understanding how resistance impacts on the parasite's fitness and pathogenicity may aid in malaria control strategy. To generate resistance, P. berghei NK65 was subjected to 5-fluoroorotate (FOA, an inhibitor of thymidylate synthase, TS) pressure in mice. After 15 generations of drug pressure, the 2% DT (the delay time for proliferation of parasites to 2% parasitaemia, relative to untreated wild-type controls) reduced from 8 days to 4, equalling the controls. Drug sensitivity studies confirmed that FOA-resistance was stable. During serial passaging in the absence of drug, resistant parasite maintained low growth rates (parasitaemia, 15.5%±2.9, 7 dpi) relative to the wild-type (45.6%±8.4), translating into resistance cost of fitness of 66.0%. The resistant parasite showed an apoptosis-like death, as confirmed by light and transmission electron microscopy and corroborated by oligonucleosomal DNA fragmentation. The resistant parasite was less fit than the wild-type, which implies that in the absence of drug pressure in the field, the wild-type alleles may expand and allow drugs withdrawn due to resistance to be reintroduced. FOA resistance led to depleted dTTP pools, causing thymineless parasite death via apoptosis. This supports the tenet that unicellular eukaryotes, like metazoans, also undergo apoptosis. This is the first report where resistance to a chemical stimulus and not the stimulus itself is shown to induce apoptosis in a unicellular parasite. This finding is relevant in cancer therapy, since thymineless cell death induced by resistance to TS-inhibitors can further be optimized via inhibition of pyrimidine salvage enzymes, thus providing a synergistic impact. We conclude that since apoptosis is a process that can be pharmacologically modulated, the parasite's apoptotic machinery may be exploited as a novel drug target in malaria and other protozoan diseases of medical importance.

Rationale for Quality Assurance in Fecal Egg Monitoring of Soil-Transmitted Helminthiasis

PubMed Central

Hoekendijk, David J. L.; Hill, Philip C.; Sowerby, Stephen J.

2016-01-01

Substantial investment has been made into the once “neglected” tropical disease, soil-transmitted helminthiasis, and into control programs that operate within a framework of mapping baseline disease distribution, measuring the effectiveness of applied interventions, establishing when to cease drug administration, and for posttreatment evaluations. However, critical to each of these stages is the determination of helminth infection. The limitations of traditional microscope-based fecal egg diagnostics have not provided quality assurance in the monitoring of parasite disease and suboptimal treatment regimes provide for the potential development of parasite resistance to anthelmintic drugs. Improved diagnostic and surveillance tools are required to protect therapeutic effectiveness and to maintain funder confidence. Such tools may be on the horizon with emergent technologies that offer potential for enhanced visualization and quality-assured quantitation of helminth eggs. PMID:27352875

Intestinal and haematic parasitism in the birds of the Almuñecar (Granada, Spain) ornithological garden.

PubMed

Cordón, G Pérez; Prados, A Hitos; Romero, D; Moreno, M Sánchez; Pontes, A; Osuna, A; Rosales, M J

2009-11-12

Birds from the Almuñecar ornithological garden (Granada, Spain) were surveyed from June 2006 to May 2007 to establish programmes to prevent, control, and treat intestinal and haematic parasites. A total of 984 faecal samples and 41 samples of blood were collected from Psittacidae, Cacatuidae, Phasianidae, and Anatidae. One or more intestinal parasites were identified in 51.6% of the samples. Blood parasites were found in 26.8% of the birds examined. The most frequent pathogenic endoparasites were coccidians, such as Cyclospora sp. (4.5%), Eimeria sp. (4.1%) and Isospora sp. (2%) and helminths such as Capillaria sp. (10. 1%), Ascaridia sp. (4.9%) and Heterakis gallinarum (4.9%). All the parasites varied with season but the most were found year round. Multiple parasitic infections by intestinal parasites were common, with 196 of 984 faecal samples having 2-5 intestinal parasites. The most frequent cases of multiple parasitism were Blastocystis plus Entamoeba sp. and Blastocystis plus Cyclospora sp. The haematic protozoa detected were Haemoproteus sp. (17%) and Plasmodium sp. (7.3%). Multiple parasitism by Haemoproteus sp. and Plasmodium sp. was detected in 1 sample of Gallus gallus. After each sampling, some of the affected animals were treated according to our results, and the corresponding programmes of prevention and control were designed.

Parasite epidemiology in a changing world: can molecular phylogeography help us tell the wood from the trees?

PubMed

Morgan, E R; Clare, E L; Jefferies, R; Stevens, J R

2012-12-01

SUMMARY Molecular phylogeography has revolutionised our ability to infer past biogeographic events from cross-sectional data on current parasite populations. In ecological parasitology, this approach has been used to address fundamental questions concerning host-parasite co-evolution and geographic patterns of spread, and has raised many technical issues and problems of interpretation. For applied parasitologists, the added complexity inherent in adding population genetic structure to perceived parasite distributions can sometimes seem to cloud rather than clarify approaches to control. In this paper, we use case studies firstly to illustrate the potential extent of cryptic diversity in parasite and parasitoid populations, secondly to consider how anthropogenic influences including movement of domestic animals affect the geographic distribution and host associations of parasite genotypes, and thirdly to explore the applied relevance of these processes to parasites of socio-economic importance. The contribution of phylogeographic approaches to deeper understanding of parasite biology in these cases is assessed. Thus, molecular data on the emerging parasites Angiostrongylus vasorum in dogs and wild canids, and the myiasis-causing flies Lucilia spp. in sheep and Cochliomyia hominovorax in humans, lead to clear implications for control efforts to limit global spread. Broader applications of molecular phylogeography to understanding parasite distributions in an era of rapid global change are also discussed.

Calcein+/PI- as an early apoptotic feature in Leishmania.

PubMed

Basmaciyan, Louise; Azas, Nadine; Casanova, Magali

2017-01-01

Although leishmaniases are responsible for high morbidity and mortality all over the world, no really satisfying treatment exists. Furthermore, the corresponding parasite Leishmania undergoes a very characteristic form of programmed cell death. Indeed, different stimuli can induce morphological and biochemical apoptotic-like features. However, the key proteins involved in mammal apoptosis, such as caspases and death receptors, are not encoded in the genome of this parasite. Currently, little is known about Leishmania apoptosis, notably owing to the lack of specific tools for programmed cell death analysis in these parasites. Furthermore, there is a need for a better understanding of Leishmania programmed cell death in order (i) to better understand the role of apoptosis in unicellular organisms, (ii) to better understand apoptosis in general through the study of an ancestral eukaryote, and (iii) to identify new therapeutic targets against leishmaniases. To advance understanding of apoptosis in Leishmania, in this study we developed a new tool based on the quantification of calcein and propidium iodide by flow cytometry. This double labeling can be employed to distinguish early apoptosis, late apoptosis and necrosis in Leishmania live cells with a very simple and rapid assay. This paper should, therefore, be of interest for people working on Leishmania and related parasites.

Association of Helicobacter pylori and protozoal parasites in patients with chronic diarrhoea.

PubMed

Yakoob, J; Abbas, Z; Khan, R; Tariq, K; Awan, S; Beg, M A

2018-02-16

Introduction An association of Helicobacter pylori and common protozoal parasites in patients with abdominal discomfort and chronic diarrhoea is unclear and may be pathological. Materials and methods One hundred and sixty-one patients with diarrhoea were compared to 114 age and sex matched controls. Stool samples were examined by microscopy and DNA extracted for PCR with specific primers for H. pylori and protozoal parasites Blastocystis sp., Entamoeba sp. (Entamoeba histolytica, Entamoeba dispar and Entamoeba moshkovskii) and Giardia duodenalis (G. duodenalis). Results There was a marked difference in the presence of parasites between patients and controls: no parasite 42/75%, one parasite 42/15%, two or more parasites 16/10%, respectively (p < 0.001). Patients with diarrhoea were more likely to be infected with Blastocystis sp (p < 0.001), E. histolytica (p = 0.027) and E moshkovskii (p = 0.003). There was no difference in the frequency of H. pylori (p = 0.528), G duodenalis (p = 0.697) or E dispar (p = 0.425). Thirty-three patients and 27 controls had H. pylori infection. Of these, 22 patients and 6 controls were infected with Blastocystis sp (p = 0.001), 6 patients and no controls were infected with E. histolytica (p = 0.02), whilst 7 patents and 9 controls were infected with E dispar (p = 0.292). Conclusion In this population, diarrhoea is linked to infection with Blastocystis sp, E. histolytica and E moshkoviskii. In H. pylori infection, diarrhoea is linked to Blastocystis sp and E. histolytica infection. These associations may be linked pathogenically.

Beyond symbiosis: cleaner shrimp clean up in culture.

PubMed

Militz, Thane A; Hutson, Kate S

2015-01-01

Cleaner organisms exhibit a remarkable natural behaviour where they consume ectoparasites attached to "client" organisms. While this behaviour can be utilized as a natural method of parasitic disease control (or biocontrol), it is not known whether cleaner organisms can also limit reinfection from parasite eggs and larvae within the environment. Here we show that cleaner shrimp, Lysmata amboinensis, consume eggs and larvae of a harmful monogenean parasite, Neobenedenia sp., in aquaculture. Shrimp consumed parasite eggs under diurnal (63%) and nocturnal (14%) conditions as well as infectious larvae (oncomiracidia) diurnally (26%). Furthermore, we trialled the inclusion of cleaner shrimp for preventative parasite management of ornamental fish, Pseudanthias squamipinnis, and found shrimp reduced oncomiracidia infection success of host fish by half compared to controls (held without shrimp). Fish held without cleaner shrimp exhibited pigmentation changes as a result of infection, possibly indicative of a stress response. These results provide the first empirical evidence that cleaner organisms reduce parasite loads in the environment through non-symbiotic cleaning activities. Our research findings have relevance to aquaculture and the marine ornamental trade, where cleaner shrimp could be applied for prophylaxis and control of ectoparasite infections.

Surveillance and diagnosis of zoonotic foodborne parasites.

PubMed

Zolfaghari Emameh, Reza; Purmonen, Sami; Sukura, Antti; Parkkila, Seppo

2018-01-01

Foodborne parasites are a source of human parasitic infection. Zoonotic infections of humans arise from a variety of domestic and wild animals, including sheep, goats, cattle, camels, horses, pigs, boars, bears, felines, canids, amphibians, reptiles, poultry, and aquatic animals such as fishes and shrimp. Therefore, the implementation of efficient, accessible, and controllable inspection policies for livestock, fisheries, slaughterhouses, and meat processing and packaging companies is highly recommended. In addition, more attention should be paid to the education of auditors from the quality control (QC) and assurance sectors, livestock breeders, the fishery sector, and meat inspection veterinarians in developing countries with high incidence of zoonotic parasitic infections. Furthermore, both the diagnosis of zoonotic parasitic infections by inexpensive, accessible, and reliable identification methods and the organization of effective control systems with sufficient supervision of product quality are other areas to which more attention should be paid. In this review, we present some examples of successful inspection policies and recent updates on present conventional, serologic, and molecular diagnostic methods for zoonotic foodborne parasites from both human infection and animal-derived foods.

Restaurant Policies and Practices for Serving Raw Fish in Minnesota.

PubMed

Hedeen, Nicole

2016-10-01

The number of restaurants serving sushi within Minnesota is continuously increasing. The practices and protocols of serving raw fish are complex and require detailed planning to ensure that food served to patrons will not cause illness. Although the popularity of sushi is increasing, there is a lack of research on food safety issues pertaining to preparation of raw fish and sushi rice. To address this gap, the Minnesota Department of Health Environmental Health Specialists Network Food program collected descriptive data on restaurant practices and policies concerning the service of raw fish and sushi rice in 40 Minnesota restaurants. At each restaurant, a specialist interviewed a restaurant manager, conducted an observation of the sushi prep areas in the restaurant kitchen, and reviewed parasite destruction letters and invoices from fish supplier(s). Over half of the restaurants (59%) were missing one or more of the parasite destruction letters from their fish supplier(s) guaranteeing that fish had been properly frozen to the time and temperature requirements in the Minnesota Food Code. A total of 42 parasite destruction letters from suppliers were observed; 10% were considered "adequate" letters. The majority of the letters were missing details pertaining to the types of fish frozen, the length of time fish were frozen, or details on what temperatures fish were held frozen or a combination of all three. Most restaurants were using time as a public health control for their sushi rice. For those restaurants using time as a public health control, 26% had a written procedure on-site, and approximately 53% were keeping track of time. Bare hand contact during sushi prep was observed in 17% of restaurants, and in more than 40% of the restaurants, at least one fish was mislabeled on the menu. Findings from this study indicate that many Minnesota restaurants are not complying with the Food Code requirements pertaining to parasite destruction for the service of raw fish or the use of time as a public health control for sushi rice.

The role of domestic dogs in the transmission of zoonotic helminthes in a rural area of Mekong river basin.

PubMed

Otake Sato, Marcello; Sato, Megumi; Yoonuan, Tippayarat; Pongvongsa, Tiengkham; Sanguankiat, Surapol; Kounnavong, Sengchanh; Maipanich, Wanna; Chigusa, Yuichi; Moji, Kazuhiko; Waikagul, Jitra

2017-06-01

Dogs have been bred since ancient times for companionship, hunting, protection, shepherding and other human activities. Some canine helminth parasites can cause significant clinical diseases in humans as Opisthorchis viverrini causing cholangiocarcinoma in Southeast Asian Countries. In this study, socio-cultural questionnaire, canine parasitological analysis, necropsy, parasite molecular confirmation and dog roaming data were evaluated in Savannakhet, Lao-PDR, a typical Mekong Basin area. Dog owners comprised 48.8% of the studied population, with 61.2% owning one dog, 25.1% 2 dogs, 8.5% 3 dogs and 1.8% owning more than 4 dogs. Data from GPS logger attached to dogs showed they walked from 1.4 to 13.3 km per day, covering an area of 3356.38m2 average, with a routine of accessing water sources. Thirteen zoonotic helminth species were observed. Causative agents of visceral and cutaneous larva migrans occurred in 44.1% and 70% of the samples respectively. Spirometra erinaceieuropaei was detected in 44.1% of samples. Importantly, O. viverrini was found in 8.8% of samples. Besides the known importance of dogs in the transmission of Ancylostoma spp., Toxocara spp. and S. erinaceieuropaei, the observed roaming pattern of dogs confirmed it as an important host perpetuating O. viverrini in endemic areas; their routine access to waterbodies may spread O. viverrini eggs in a favorable environment for the fluke development, facilitating the infection of fishes, and consequently infecting humans living in the same ecosystem. Therefore, parasitic NTDs control programs in humans should be done in parallel with parasite control in animals, especially dogs, in the Mekong River basin area.

Population Genetics of Schistosoma japonicum within the Philippines Suggest High Levels of Transmission between Humans and Dogs

PubMed Central

Rudge, James W.; Carabin, Hélène; Balolong, Ernesto; Tallo, Veronica; Shrivastava, Jaya; Lu, Da-Bing; Basáñez, María-Gloria; Olveda, Remigio; McGarvey, Stephen T.; Webster, Joanne P.

2008-01-01

Background Schistosoma japonicum, which remains a major public health problem in the Philippines and mainland China, is the only schistosome species for which zoonotic transmission is considered important. While bovines are suspected as the main zoonotic reservoir in parts of China, the relative contributions of various non-human mammals to S. japonicum transmission in the Philippines remain to be determined. We examined the population genetics of S. japonicum in the Philippines in order to elucidate transmission patterns across host species and geographic areas. Methodology/Principal Findings S. japonicum miracidia (hatched from eggs within fecal samples) from humans, dogs, pigs and rats, and cercariae shed from snail-intermediate hosts, were collected across two geographic areas of Samar Province. Individual isolates were then genotyped using seven multiplexed microsatellite loci. Wright's FST values and phylogenetic trees calculated for parasite populations suggest a high frequency of parasite gene-flow across definitive host species, particularly between dogs and humans. Parasite genetic differentiation between areas was not evident at the definitive host level, possibly suggesting frequent import and export of infections between villages, although there was some evidence of geographic structuring at the snail–intermediate host level. Conclusions/Significance These results suggest very high levels of transmission across host species, and indicate that the role of dogs should be considered when planning control programs. Furthermore, a regional approach to treatment programs is recommended where human migration is extensive. PMID:19030225

Parasites of fishes in the Colorado River and selected tributaries in Grand Canyon, Arizona.

USGS Publications Warehouse

Cole, Rebecca A.; Sterner, Mauritz C.; Linder, Chad; Hoffnagle, Timothy L.; Persons, Bill; Choudhury, Anindo; Haro, Roger

2012-01-01

As part of the endangered humpback chub (HBC; Gila cypha) Adaptive Management Program, a parasite survey was conducted from 28 June to 17 July 2006 in 8 tributaries and 7 adjacent sections of the main stem of the Colorado River, U.S.A. In total, 717 fish were caught, including 24 HBC. Field necropsies yielded 19 parasite species, 5 of which (Achtheres sp., Kathlaniidae gen. sp., Caryophyllaidae gen. sp., Myxidium sp., and Octomacrum sp.) are new records for Grand Canyon, Arizona, U.S.A. Spearman's correlation coefficient analyses showed no correlations between parasite burden and fork length for various combinations of fish and parasite species. Regression analyses suggest that no parasite species had a strong effect on fish length. The most diverse parasite community (n=14) was at river kilometer (Rkm) 230, near the confluence of Kanab Creek. The most diverse parasite infracommunity (n=12) was found in the non-native channel catfish (CCF; Ictaluris punctatus). Overall parasite prevalence was highest in CCF (85%) followed by that in HBC (58%). The parasite fauna of humpback chub was mainly composed of Bothriocephalus acheilognathi and Ornithodiplostomum sp. metacercariae.

Trade-Off Between Fitness Gain and Cost Determines Profitability of a Peach Aphid Parasitoid.

PubMed

Khatri, Diwas; He, Xiong Z; Wang, Qiao

2016-08-01

Aphidius colemani (Viereck) (Hymenoptera: Aphidiidae) is commercially produced and utilized for biological control of peach aphid Myzus persicae (Sulzer) (Hemiptera: Aphididae) on greenhouse crops in many countries. To provide knowledge for the evaluation of parasitoid-host interactions and development of effective mass rearing programs, we investigated how and why host age or size affected fitness gain in A. colemani We show that the parasitoid was significantly more likely to encounter larger hosts and that an encounter almost always triggered an attack attempt. However, the attack attempt did not proportionally translate into oviposition because larger aphids had greater ability to defend themselves and the parasitoid spent more time in handling larger aphids. The host age at parasitization had no effect on emergence rates and sex ratio of parasitoid progeny, suggesting that pupae and larvae have similar survival rate in hosts of different ages and/or the parasitoid females do not adjust sex allocation based on host size. When parasitizing mid-aged hosts, the parasitoid gained maximum fitness for their progeny in developmental period, body size, and parasitism. Taking all findings together, we suggest that parasitizing mid-aged green peach aphid nymphs is most profitable for A. colemani. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Bulk tank milk prevalence and production losses, spatial analysis, and predictive risk mapping of Ostertagia ostertagi infections in Mexican cattle herds.

PubMed

Villa-Mancera, Abel; Pastelín-Rojas, César; Olivares-Pérez, Jaime; Córdova-Izquierdo, Alejandro; Reynoso-Palomar, Alejandro

2018-05-01

This study investigated the prevalence, production losses, spatial clustering, and predictive risk mapping in different climate zones in five states of Mexico. The bulk tank milk samples obtained between January and April 2015 were analyzed for antibodies against Ostertagia ostertagi using the Svanovir ELISA. A total of 1204 farm owners or managers answered the questionnaire. The overall herd prevalence and mean optical density ratio (ODR) of parasite were 61.96% and 0.55, respectively. Overall, the production loss was approximately 0.542 kg of milk per parasited cow per day (mean ODR = 0.92, 142 farms, 11.79%). The spatial disease cluster analysis using SatScan software indicated that two high-risk clusters were observed. In the multivariable analysis, three models were tested for potential association with the ELISA results supported by climatic, environmental, and management factors. The final logistic regression model based on both climatic/environmental and management variables included the factors rainfall, elevation, land surface temperature (LST) day, and parasite control program that were significantly associated with an increased risk of infection. Geostatistical kriging was applied to generate a risk map for the presence of parasite in dairy cattle herds in Mexico. The results indicate that climatic and meteorological factors had a higher potential impact on the spatial distribution of O. ostertagi than the management factors.

Molecular Detection of Plasmodium malariae/Plasmodium brasilianum in Non-Human Primates in Captivity in Costa Rica.

PubMed

Fuentes-Ramírez, Alicia; Jiménez-Soto, Mauricio; Castro, Ruth; Romero-Zuñiga, Juan José; Dolz, Gaby

2017-01-01

One hundred and fifty-two blood samples of non-human primates of thirteen rescue centers in Costa Rica were analyzed to determine the presence of species of Plasmodium using thick blood smears, semi-nested multiplex polymerase chain reaction (SnM-PCR) for species differentiation, cloning and sequencing for confirmation. Using thick blood smears, two samples were determined to contain the Plasmodium malariae parasite, with SnM-PCR, a total of five (3.3%) samples were positive to P. malariae, cloning and sequencing confirmed both smear samples as P. malariae. One sample amplified a larger and conserved region of 18S rDNA for the genus Plasmodium and sequencing confirmed the results obtained microscopically and through SnM-PCR tests. Sequencing and construction of a phylogenetic tree of this sample revealed that the P. malariae/P. brasilianum parasite (GenBank KU999995) found in a howler monkey (Alouatta palliata) is identical to that recently reported in humans in Costa Rica. The SnM-PCR detected P. malariae/P. brasilianum parasite in different non-human primate species in captivity and in various regions of the southern Atlantic and Pacific coast of Costa Rica. The similarity of the sequences of parasites found in humans and a monkey suggests that monkeys may be acting as reservoirs of P.malariae/P. brasilianum, for which reason it is important, to include them in control and eradication programs.

Technique for controlling spread of limnotic oncomelania

NASA Astrophysics Data System (ADS)

Li, Damei; Wang, Xiangsan; Lai, Yonggen

2003-09-01

Schistosomiasis is a parasitic disease mostly found in areas along the Changjiang River of China. The disease is spread solely through an intermediary named oncomelania, so its spread of schistosomiasis can be controlled by properly designing water intakes which prevent oncomelania from entering farming land or residential areas. This paper reports a successful design process and a new oncomelania-free intake device. The design of the new intake is based on a sound research program in which extensive experimental studies were carried out to gain knowledge of oncomelania eco-hydraulic behavior and detailed flow field information through CFD simulation.

Development of conventional and real-time multiplex PCR-based assays for estimation of natural infection rates and Trypanosoma cruzi load in triatomine vectors.

PubMed

Moreira, Otacilio C; Verly, Thaiane; Finamore-Araujo, Paula; Gomes, Suzete A O; Lopes, Catarina M; de Sousa, Danielle M; Azevedo, Lívia R; da Mota, Fabio F; d'Avila-Levy, Claudia M; Santos-Mallet, Jacenir R; Britto, Constança

2017-08-29

Chagas disease is a complex anthropozoonosis with distinct domestic and sylvatic mammal species acting as potential reservoirs. The diversity of vector species and their habitats are among the factors that hinder the control of the disease. Control programs periodically monitor the prevalence of T. cruzi infection in insect bugs through microscopical observation of diluted feces. However, microscopy presents limited sensitivity in samples with low parasite numbers, difficulties in examining all evolutionary stages of the insect and may in turn be limited to differentiate T. cruzi from other morphologically similar trypanosomatids. Here, we report two highly sensitive and accurate methodologies to infer T. cruzi infection rates and to quantify parasite load in the gut of field-collected triatomines. Triatomines were manually collected in the period 2011-2012 and 2014-2015, in domestic, peridomestic or sylvatic habitats in rural areas of 26 municipalities, encompassing three distinct Brazilian biomes: Caatinga, Cerrado and Atlantic Rainforest. Following morphological and taxonomical identification, the search for flagellated protozoa was performed by optical microscopy. A conventional PCR targeting T. cruzi kDNA and a TaqMan qPCR directed to the parasite nuclear satellite DNA (SAT) were developed, both in multiplex, with the triatomine 12S subunit ribosomal RNA gene, used as internal amplification control. Both methods were used for detection (kDNA-PCR) and parasite load quantification (SAT-DNA-qPCR), to investigate T. cruzi infection in captured triatomines. The combined methods were assayed on a panel of 205 field-collected triatomine samples. Diagnostic analysis revealed 21% positivity for the kDNA-PCR, whereas microscopic examination enabled identification of T. cruzi in only 7.0% of the PCR-positive samples. Negative PCR results were confirmed by the absence of T. cruzi flagellates using microscopy. Caatinga biome yielded the highest T. cruzi infection rate (60%), followed by the Atlantic Rainforest and Cerrado with 7.1 and 6.1%, respectively. In addition, a wide range distribution of parasite load, varying from 8.05 × 10 -2 to 6.31 × 10 10 was observed with a median of 2.29 × 10 3  T. cruzi/intestine units. When parasite load was analyzed by triatomine species, a significantly higher median was found for Panstrongylus lutzi in comparison with Triatoma brasiliensis. Our results demonstrate highly sensitive PCR-based methodologies to monitor T. cruzi infection in triatomines. In addition, the qPCR assay offers the possibility of further evaluation parasite load, as a promising biomarker of the vectorial capacity of triatomines in Chagas disease endemic areas.

21 CFR 520.1870 - Praziquantel tablets.

Code of Federal Regulations, 2011 CFR

2011-04-01

... debilitated animals and for assistance in the diagnosis, treatment, and control of parasitism. (B) If labeled..., treatment, and control of parasitism. [46 FR 60570, Dec. 11, 1981, as amended at 47 FR 26377, June 18, 1982...

21 CFR 500.25 - Anthelmintic drugs for use in animals.

Code of Federal Regulations, 2010 CFR

2010-04-01

..., and control of parasitism. (b) The label and any labeling furnishing or purporting to furnish... assistance in the diagnosis, treatment, and control of parasitism.” (c) For drugs covered by approved new...

21 CFR 500.25 - Anthelmintic drugs for use in animals.

Code of Federal Regulations, 2011 CFR

2011-04-01

..., and control of parasitism. (b) The label and any labeling furnishing or purporting to furnish... assistance in the diagnosis, treatment, and control of parasitism.” (c) For drugs covered by approved new...

Adaptive Augmenting Control Flight Characterization Experiment on an F/A-18

NASA Technical Reports Server (NTRS)

VanZwieten, Tannen S.; Orr, Jeb S.; Wall, John H.; Gilligan, Eric T.

2014-01-01

This paper summarizes the Adaptive Augmenting Control (AAC) flight characterization experiments performed using an F/A-18 (TN 853). AAC was designed and developed specifically for launch vehicles, and is currently part of the baseline autopilot design for NASA's Space Launch System (SLS). The scope covered here includes a brief overview of the algorithm (covered in more detail elsewhere), motivation and benefits of flight testing, top-level SLS flight test objectives, applicability of the F/A-18 as a platform for testing a launch vehicle control design, test cases designed to fully vet the AAC algorithm, flight test results, and conclusions regarding the functionality of AAC. The AAC algorithm developed at Marshall Space Flight Center is a forward loop gain multiplicative adaptive algorithm that modifies the total attitude control system gain in response to sensed model errors or undesirable parasitic mode resonances. The AAC algorithm provides the capability to improve or decrease performance by balancing attitude tracking with the mitigation of parasitic dynamics, such as control-structure interaction or servo-actuator limit cycles. In the case of the latter, if unmodeled or mismodeled parasitic dynamics are present that would otherwise result in a closed-loop instability or near instability, the adaptive controller decreases the total loop gain to reduce the interaction between these dynamics and the controller. This is in contrast to traditional adaptive control logic, which focuses on improving performance by increasing gain. The computationally simple AAC attitude control algorithm has stability properties that are reconcilable in the context of classical frequency-domain criteria (i.e., gain and phase margin). The algorithm assumes that the baseline attitude control design is well-tuned for a nominal trajectory and is designed to adapt only when necessary. Furthermore, the adaptation is attracted to the nominal design and adapts only on an as-needed basis (see Figure 1). The MSFC algorithm design was formulated during the Constellation Program and reached a high maturity level during SLS through simulation-based development and internal and external analytical review. The AAC algorithm design has three summary-level objectives: (1) "Do no harm;" return to baseline control design when not needed, (2) Increase performance; respond to error in ability of vehicle to track command, and (3) Regain stability; respond to undesirable control-structure interaction or other parasitic dynamics. AAC has been successfully implemented as part of the Space Launch System baseline design, including extensive testing in high-fidelity 6-DOF simulations the details of which are described in [1]. The Dryden Flight Research Center's F/A-18 Full-Scale Advanced Systems Testbed (FAST) platform is used to conduct an algorithm flight characterization experiment intended to fully vet the aforementioned design objectives. FAST was specifically designed with this type of test program in mind. The onboard flight control system has full-authority experiment control of ten aerodynamic effectors and two throttles. It has production and research sensor inputs and pilot engage/disengage and real-time configuration of up to eight different experiments on a single flight. It has failure detection and automatic reversion to fail-safe mode. The F/A-18 aircraft has an experiment envelope cleared for full-authority control and maneuvering and exhibits characteristics for robust recovery from unusual attitudes and configurations aided by the presence of a qualified test pilot. The F/A-18 aircraft has relatively high mass and inertia with exceptional performance; the F/A-18 also has a large thrust-to-weight ratio, owing to its military heritage. This enables the simulation of a portion of the ascent trajectory with a high degree of dynamic similarity to a launch vehicle, and the research flight control system can simulate unstable longitudinal dynamics. Parasitic dynamics such as slosh and bending modes, as well as atmospheric disturbances, are being produced by the airframe via modification of bending filters and the use of secondary control surfaces, including leading and trailing edge flaps, symmetric ailerons, and symmetric rudders. The platform also has the ability to inject signals in flight to simulate structural mode resonances or other challenging dynamics. This platform also offers more test maneuvers and longer maneuver times than a single rocket or missile test, which provides ample opportunity to fully and repeatedly exercise all aspects of the algorithm. Prior to testing on an F/A-18, AAC was the only component of the SLS autopilot design that had not been flight tested. The testing described in this paper raises the Technology Readiness Level (TRL) early in the SLS Program and is able to demonstrate its capabilities and robustness in a flight environment.

Can a single "powerless" mitochondrion in the malaria parasite contribute to parasite programmed cell death in the asexual stages?

PubMed

Ch'ng, Jun-Hong; Yeo, Su-Ping; Shyong-Wei Tan, Kevin

2013-05-01

The protozoan pathogens responsible for malaria are from the Plasmodium genus, with Plasmodium falciparum and Plasmodium vivax accounting for almost all clinical infections. With recent estimates of mortality exceeding 800,000 annually, malaria continues to take a terrible toll on lives and the early promises of medicine to eradicate the disease have yet to approach realization, in part due to the spread of drug resistant parasites. Recent reports of artemisinin-resistance have prompted renewed efforts to identify novel therapeutic options, and one such pathway being considered for antimalarial exploit is the parasite's programmed cell death (PCD) pathway. In this mini-review, we will discuss the roles of the plasmodium mitochondria in cell death and as a target of antimalarial compounds, taking into account recent data suggesting that PCD pathways involving the mitochondria may be attractive antimalarial targets. Copyright © 2012 Elsevier B.V. and Mitochondria Research Society. All rights reserved.

A Novel Molecular Test to Diagnose Canine Visceral Leishmaniasis at the Point of Care

PubMed Central

Castellanos-Gonzalez, Alejandro; Saldarriaga, Omar A.; Tartaglino, Lilian; Gacek, Rosana; Temple, Elissa; Sparks, Hayley; Melby, Peter C.; Travi, Bruno L.

2015-01-01

Dogs are the principal reservoir hosts of zoonotic visceral leishmaniasis (VL) but current serological methods are not sensitive enough to detect all subclinically infected animals, which is crucial to VL control programs. Polymerase chain reaction (PCR) methods have greater sensitivity but require expensive equipment and trained personnel, impairing its implementation in endemic areas. We developed a diagnostic test that uses isothermal recombinase polymerase amplification (RPA) to detect Leishmania infantum. This method was coupled with lateral flow (LF) reading with the naked eye to be adapted as a point-of-care test. The L. infantum RPA-LF had an analytical sensitivity similar to real time-PCR, detecting DNA of 0.1 parasites spiked in dog blood, which was equivalent to 40 parasites/mL. There was no cross amplification with dog or human DNA or with Leishmania braziliensis, Leishmania amazonensis, or Trypanosoma cruzi. The test also amplified Leishmania donovani strains (N = 7). In a group of clinically normal dogs (N = 30), RPA-LF detected more subclinical infections than rK39 strip test, a standard serological method (50% versus 13.3% positivity, respectively; P = 0.005). Also, RPA-LF detected L. infantum in noninvasive mucosal samples of dogs with a sensitivity comparable to blood samples. This novel molecular test may have a positive impact in leishmaniasis control programs. PMID:26240156

Country specific predictions of the cost-effectiveness of malaria vaccine RTS,S/AS01 in endemic Africa.

PubMed

Galactionova, Katya; Tediosi, Fabrizio; Camponovo, Flavia; Smith, Thomas A; Gething, Peter W; Penny, Melissa A

2017-01-03

RTS,S/AS01 is a safe and moderately efficacious vaccine considered for implementation in endemic Africa. Model predictions of impact and cost-effectiveness of this new intervention could aid in country adoption decisions. The impact of RTS,S was assessed in 43 countries using an ensemble of models of Plasmodium falciparum epidemiology. Informed by the 32months follow-up data from the phase 3 trial, vaccine effectiveness was evaluated at country levels of malaria parasite prevalence, coverage of control interventions and immunization. Benefits and costs of the program incremental to routine malaria control were evaluated for a four dose schedule: first dose administered at six months, second and third - before 9months, and fourth dose at 27months of age. Sensitivity analyses around vaccine properties, transmission, and economic inputs were conducted. If implemented in all 43 countries the vaccine has the potential to avert 123 (117;129) million malaria episodes over the first 10years. Burden averted averages 18,413 (range of country median estimates 156-40,054) DALYs per 100,000 fully vaccinated children with much variation across settings primarily driven by differences in transmission intensity. At a price of $5 per dose program costs average $39.8 per fully vaccinated child with a median cost-effectiveness ratio of $188 (range $78-$22,448) per DALY averted; the ratio is lower by one third - $136 (range $116-$220) - in settings where parasite prevalence in children aged 2-10years is at or above 10%. RTS,S/AS01has the potential to substantially reduce malaria burden in children across Africa. Conditional on assumptions on price, coverage, and vaccine properties, adding RTS,S to routine malaria control interventions would be highly cost-effective. Implementation decisions will need to further consider feasibility of scaling up existing control programs, and operational constraints in reaching children at risk with the schedule. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Ecosystem energetic implications of parasite and free-living biomass in three estuaries

USGS Publications Warehouse

Kuris, Armand M.; Hechinger, Ryan F.; Shaw, Jenny C.; Whitney, Kathleen L.; Aguirre-Macedo, Leopoldina; Boch, Charlie A.; Dobson, Andrew P.; Dunham, Eleca J.; Fredensborg, Brian L.; Huspeni, Todd C.; Lorda, Julio; Mababa, Luzviminda; Mancini, Frank T.; Mora, Adrienne B.; Pickering, Maria; Talhouk, Nadia L.; Torchin, Mark E.; Lafferty, Kevin D.

2008-01-01

Parasites can have strong impacts but are thought to contribute little biomass to ecosystems. We quantified the biomass of free-living and parasitic species in three estuaries on the Pacific coast of California and Baja California. Here we show that parasites have substantial biomass in these ecosystems. We found that parasite biomass exceeded that of top predators. The biomass of trematodes was particularly high, being comparable to that of the abundant birds, fishes, burrowing shrimps and polychaetes. Trophically transmitted parasites and parasitic castrators subsumed more biomass than did other parasitic functional groups. The extended phenotype biomass controlled by parasitic castrators sometimes exceeded that of their uninfected hosts. The annual production of free-swimming trematode transmission stages was greater than the combined biomass of all quantified parasites and was also greater than bird biomass. This biomass and productivity of parasites implies a profound role for infectious processes in these estuaries.

Parasites in marine food webs

USGS Publications Warehouse

Lafferty, Kevin D.

2013-01-01

Most species interactions probably involve parasites. This review considers the extent to which marine ecologists should consider parasites to fully understand marine communities. Parasites are influential parts of food webs in estuaries, temperate reefs, and coral reefs, but their ecological importance is seldom recognized. Though difficult to observe, parasites can have substantial biomass, and they can be just as common as free-living consumers after controlling for body mass and trophic level. Parasites have direct impacts on the energetics of their hosts and some affect host behaviors, with ecosystem-level consequences. Although they cause disease, parasites are sensitive components of ecosystems. In particular, they suffer secondary extinctions due to biodiversity loss. Some parasites can also return to a system after habitat restoration. For these reasons, parasites can make good indicators of ecosystem integrity. Fishing can indirectly increase or decrease parasite populations and the effects of climate change on parasites are likely to be equally as complex.

Intestinal Parasite Co-infection among Pulmonary Tuberculosis Cases without Human Immunodeficiency Virus Infection in a Rural County in China

PubMed Central

Li, Xin-Xu; Chen, Jia-Xu; Wang, Li-Xia; Tian, Li-Guang; Zhang, Yu-Ping; Dong, Shuang-Pin; Hu, Xue-Guang; Liu, Jian; Wang, Feng-Feng; Wang, Yue; Yin, Xiao-Mei; He, Li-Jun; Yan, Qiu-Ye; Zhang, Hong-Wei; Xu, Bian-Li; Zhou, Xiao-Nong

2014-01-01

Epidemiologic studies of co-infection with tuberculosis (TB) and intestinal parasites in humans have not been extensively investigated in China. A cross-section study was conducted in a rural county of Henan Province, China. Pulmonary TB (PTB) case-patients receiving treatment for infection with Mycobacterium tuberculosis and healthy controls matched for geographic area, age, and sex were surveyed by using questionnaires. Fecal and blood specimens were collected for detection of intestinal parasites, routine blood examination, and infection with human immunodeficiency virus. The chi-square test was used for univariate analysis and multivariate logistic regression models were used to adjust for potential confounding factors. A total of 369 persons with PTB and 366 healthy controls were included; all participants were negative for human immunodeficiency virus. The overall prevalence of intestinal parasites in persons with PTB was 14.9%, including intestinal protozoa (7.9%) and helminthes (7.6%). The infection spectrum of intestinal parasites was Entamoeba spp. (1.4%), Blastocystis hominis (6.2%), Trichomonas hominis (0.3%), Clonorchis sinensis (0.3%), Ascaris lumbricoides (0.5%), Trichuris trichiura (2.2%), and hookworm (4.6%). The prevalence of intestinal parasites showed no significant difference between persons with PTB and healthy controls after adjusting for potential confounding factors. There was no factor that affected infection rates for intestinal parasites between the two groups. Infection with intestinal parasites of persons with PTB was associated with female sex (adjusted odds ratio [AOR] = 2.05, 95% confidence interval [CI] = 1.01–4.17), body mass index ≤ 19 (AOR = 3.02, 95% CI = 1.47–6.20), and anemia (AOR = 2.43, 95% CI = 1.17–5.03). Infection of healthy controls was only associated with an annual labor time in farmlands > 2 months (AOR = 4.50, 95% CI = 2.03–10.00). In addition, there was no significant trend between rates of infection with intestinal parasites and duration of receiving treatment for infection with M. tuberculosis in persons with PTB. The prevalence of intestinal parasites was not higher in persons with PTB, and there was no evidence that PTB increased susceptibility to intestinal parasites in this study. However, for patients with PTB, women and patients with comorbidities were more likely to be infected with intestinal parasites. PMID:24166044

Genetic variability and population structure of Plasmodium falciparum parasite populations from different malaria ecological regions of Kenya.

PubMed

Ingasia, Luicer A; Cheruiyot, Jelagat; Okoth, Sheila Akinyi; Andagalu, Ben; Kamau, Edwin

2016-04-01

Transmission intensity, movement of human and vector hosts, biogeographical features, and malaria control measures are some of the important factors that determine Plasmodium falciparum parasite genetic variability and population structure. Kenya has different malaria ecologies which might require different disease intervention methods. Refined parasite population genetic studies are critical for informing malaria control and elimination strategies. This study describes the genetic diversity and population structure of P. falciparum parasites from the different malaria ecological zones in Kenya. Twelve multi-locus microsatellite (MS) loci previously described were genotyped in 225 P. falciparum isolates collected between 2012 and 2013 from five sites; three in lowland endemic regions (Kisumu, Kombewa, and Malindi) and two in highland, epidemic regions (Kisii and Kericho). Parasites from the lowland endemic and highland epidemic regions of western Kenya had high genetic diversity compared to coastal lowland endemic region of Kenya [Malindi]. The Kenyan parasites had a mean genetic differentiation index (FST) of 0.072 (p=0.011). The multi-locus genetic analysis of the 12 MS revealed all the parasites had unique haplotypes. Significant linkage disequilibrium (LD) was observed in all the five parasite populations. Kisumu had the most significant index of association values (0.16; p<0.0001) whereas Kisii had the least significant index of association values (0.03; p<0.0001). Our data suggest high genetic diversity in Kenyan parasite population with the exception of parasite from Malindi where malaria has been on the decline. The presence of significant LD suggests that there is occurrence of inbreeding in the parasite population. Parasite populations from Kisii showed the strongest evidence for epidemic population structure whereas the rest of the regions showed panmixia. Defining the genetic diversity of the parasites in different ecological regions of Kenya after introduction of the artemether-lumefantrine is important in refining the spread of drug resistant strains and malaria transmission for more effective control and eventual elimination of malaria in Kenya. Copyright © 2015. Published by Elsevier B.V.

Plasmodium falciparum Calcium-Dependent Protein Kinase 2 Is Critical for Male Gametocyte Exflagellation but Not Essential for Asexual Proliferation.

PubMed

Bansal, Abhisheka; Molina-Cruz, Alvaro; Brzostowski, Joseph; Mu, Jianbing; Miller, Louis H

2017-10-17

Drug development efforts have focused mostly on the asexual blood stages of the malaria parasite Plasmodium falciparum Except for primaquine, which has its own limitations, there are no available drugs that target the transmission of the parasite to mosquitoes. Therefore, there is a need to validate new parasite proteins that can be targeted for blocking transmission. P. falciparum calcium-dependent protein kinases ( Pf CDPKs) play critical roles at various stages of the parasite life cycle and, importantly, are absent in the human host. These features mark them as attractive drug targets. In this study, using CRISPR/Cas9 we successfully knocked out Pf CDPK2 from blood-stage parasites, which was previously thought to be an indispensable protein. The growth rate of the Pf CDPK2 knockout (KO) parasites was similar to that of wild-type parasites, confirming that Pf CDPK2 function is not essential for the asexual proliferation of the parasite in vitro The mature male and female gametocytes of Pf CDPK2 KO parasites become round after induction. However, they fail to infect female Anopheles stephensi mosquitoes due to a defect(s) in male gametocyte exflagellation and possibly in female gametes. IMPORTANCE Despite reductions in the number of deaths it causes, malaria continues to be a leading infectious disease of the developing world. For effective control and elimination of malaria, multiple stages of the parasite need to be targeted. One such stage includes the transmission of the parasite to mosquitoes. Here, we demonstrate the successful knockout of Pf CDPK2, which was previously thought to be indispensable for parasite growth in red blood cells. The Pf CDPK2 KO parasites are incapable of establishing an infection in mosquitoes. Therefore, our study suggests that targeting Pf CDPK2 may be a good strategy to control malaria transmission in countries with high transmission. Moreover, molecular understanding of the signaling pathway of Pf CDPK2 may provide additional targets for malaria control. Copyright © 2017 Bansal et al.

Parasitic nematode interactions with mammals and plants.

PubMed

Jasmer, Douglas P; Goverse, Aska; Smant, Geert

2003-01-01

Parasitic nematodes that infect humans, animals, and plants cause serious diseases that are deleterious to human health and agricultural productivity. Chemical and biological control methods have reduced the impact of these parasites. However, surviving environmental stages lead to persistent reinfection of host species. In addition, development of resistance to nematicides and anthelmintics by these parasites and reduced availability of some nematicides, for environmental protection, pose significant obstacles for current and future prospects of effective parasite control. Due to marked differences in host species, research on animal and plant parasitic nematodes often proceeds independently. Despite the differences between animals and plants, basic cellular properties are shared among these host organisms. Some common properties may be important for mechanisms [homologous or convergent (homoplastic)] by which nematodes successfully infect these diverse hosts or by which animal and plant hosts resist infections by these pathogens. Here we compare host/parasite interactions between plant parasitic nematodes (PPN) and animal parasitic nematodes, with an emphasis on mammalian hosts (MPN). Similarities and differences are considered in the context of progress on molecular dissection of these interactions. A comprehensive coverage is not possible in the space allotted. Instead, an illustrative approach is used to establish examples that, it is hoped, exemplify the value of the comparative approach.

Gastrointestinal parasite egg excretion in young calves in periurban livestock production in Mali.

PubMed

Wymann, Monica Natalie; Traore, Koniba; Bonfoh, Bassirou; Tembely, Saïdou; Tembely, Sékouba; Zinsstag, Jakob

2008-04-01

To acquire the information needed to improve parasite control in periurban cattle production in Mali, repeated sampling of faeces of 694 calves kept around Bamako was done in 2003/2004. The effects of season, age, breed, management type, parasite control and presence of sheep on egg and oocyst counts were determined. A Bayesian model was used with a negative binomial distribution and herd and individual effects, to account for the clustering of calves in herds and the repeated sampling. Interviews were conducted to report the current control strategies. We found eggs of Strongyloides papillosus (Age class 0-1 month: prevalence 39%, 2-3 months: 59%, 5-6 months: 42%), strongyles (14%, 24%, 36%), coccidian oocysts (37%, 68%, 64%) and at low prevalence eggs of Toxocara vitulorum, Moniezia sp., Trichuris sp. and Paramphistomum sp. Season and age effects occurred. Reported utilisation of parasite control was high (92%) but monthly recorded use was significantly lower (61%).

Gastrointestinal parasites of feral cats from Christmas Island.

PubMed

Adams, P J; Elliot, A D; Algar, D; Brazell, R I

2008-01-01

To investigate the gastrointestinal parasites present in feral cats on Christmas Island, with particular interest in the protozoan parasite Toxoplasma gondii. Faecal and serum samples were collected from 28 and 25 cats respectively that were trapped as part of an ongoing eradication program being run on Christmas Island by the Department of Environment and Conservation. Faecal samples were screened microscopically for helminth and protozoan parasites. Serum samples were screened for antibodies to T gondii using a commercial indirect immunofluorescence assay (IFA) and a latex agglutination test (LAT). The most common helminth parasites detected were Toxocara cati (present in 15 of 28 faecal samples), Strongyloides sp (13/28), Aelurostrongylus abstrusus, (7/28), an unidentified capillarid (6/28) and Ancylostoma sp (4/28). Based on serology, T gondii was the most common parasite detected (protozoan or otherwise) with antibodies detected in 24 serum samples by IFA and 23 serum samples by LAT. Cats on Christmas Island harbour many of the helminth and protozoan parasites reported from feral cats elsewhere in Australia. The high seroprevalence of T gondii in these cats indicates a high level of exposure to the parasite in this environment.

Excretory-secretory antigens: a suitable candidate for immunization against ocular toxoplasmosis in a murine model.

PubMed

Norouzpour Deilami, Kiumars; Daryani, Ahmad; Ahmadpour, Ehsan; Sharif, Mehdi; Dadimoghaddam, Yousef; Sarvi, Shahabeddin; Alizadeh, Ahad

2014-12-01

Toxoplasmosis, responsible for ocular impairment, is caused by Toxoplasma gondii. We investigated the effect of Toxoplasma excretory-secretory antigens (ESA) on parasite load and distribution in the eye tissue of a murine model. Case and control groups were immunized with ESA and PBS, respectively. Two weeks after the second immunization, the mice were challenged intraperitoneally with virulent RH strain of Toxoplasma; eye tissue samples of both groups were collected daily (days 1, 2, 3, and the last day before death). Parasite load was determined using real-time quantitative PCR targeted at the B1 gene. Compared to the control group, infected mice that received ESA vaccine presented a considerable decrease in parasite load in the eye tissue, demonstrating the effect of ESA on parasite load and distribution. Diminution of parasite load in mouse eye tissue indicated that ESA might help control disease-related complications and could be a valuable immunization candidate against ocular toxoplasmosis. Copyright © 2014 Elsevier Ltd. All rights reserved.

Genetic Surveillance Detects Both Clonal and Epidemic Transmission of Malaria following Enhanced Intervention in Senegal

PubMed Central

Séne, Papa Diogoye; Park, Danny C.; Neafsey, Daniel E.; Schaffner, Stephen F.; Hamilton, Elizabeth J.; Lukens, Amanda K.; Van Tyne, Daria; Mboup, Souleymane; Sabeti, Pardis C.; Ndiaye, Daouda; Wirth, Dyann F.

2013-01-01

Using parasite genotyping tools, we screened patients with mild uncomplicated malaria seeking treatment at a clinic in Thiès, Senegal, from 2006 to 2011. We identified a growing frequency of infections caused by genetically identical parasite strains, coincident with increased deployment of malaria control interventions and decreased malaria deaths. Parasite genotypes in some cases persisted clonally across dry seasons. The increase in frequency of genetically identical parasite strains corresponded with decrease in the probability of multiple infections. Further, these observations support evidence of both clonal and epidemic population structures. These data provide the first evidence of a temporal correlation between the appearance of identical parasite types and increased malaria control efforts in Africa, which here included distribution of insecticide treated nets (ITNs), use of rapid diagnostic tests (RDTs) for malaria detection, and deployment of artemisinin combination therapy (ACT). Our results imply that genetic surveillance can be used to evaluate the effectiveness of disease control strategies and assist a rational global malaria eradication campaign. PMID:23593309

Experimental Vaccines against Chagas Disease: A Journey through History.

PubMed

Rodríguez-Morales, Olivia; Monteón-Padilla, Víctor; Carrillo-Sánchez, Silvia C; Rios-Castro, Martha; Martínez-Cruz, Mariana; Carabarin-Lima, Alejandro; Arce-Fonseca, Minerva

2015-01-01

Chagas disease, or American trypanosomiasis, which is caused by the protozoan parasite Trypanosoma cruzi, is primarily a vector disease endemic in 21 Latin American countries, including Mexico. Although many vector control programs have been implemented, T. cruzi has not been eradicated. The development of an anti-T. cruzi vaccine for prophylactic and therapeutic purposes may significantly contribute to the transmission control of Chagas disease. Immune protection against experimental infection with T. cruzi has been studied since the second decade of the last century, and many types of immunogens have been used subsequently, such as killed or attenuated parasites and new DNA vaccines. This primary prevention strategy appears feasible, effective, safe, and inexpensive, although problems remain. The objective of this review is to summarize the research efforts about the development of vaccines against Chagas disease worldwide. A thorough literature review was conducted by searching PubMed with the terms "Chagas disease" and "American trypanosomiasis" together with "vaccines" or "immunization". In addition, reports and journals not cited in PubMed were identified. Publications in English, Spanish, and Portuguese were reviewed.

Advances in the application of genetic manipulation methods to apicomplexan parasites.

PubMed

Suarez, C E; Bishop, R P; Alzan, H F; Poole, W A; Cooke, B M

2017-10-01

Apicomplexan parasites such as Babesia, Theileria, Eimeria, Cryptosporidium and Toxoplasma greatly impact animal health globally, and improved, cost-effective measures to control them are urgently required. These parasites have complex multi-stage life cycles including obligate intracellular stages. Major gaps in our understanding of the biology of these relatively poorly characterised parasites and the diseases they cause severely limit options for designing novel control methods. Here we review potentially important shared aspects of the biology of these parasites, such as cell invasion, host cell modification, and asexual and sexual reproduction, and explore the potential of the application of relatively well-established or newly emerging genetic manipulation methods, such as classical transfection or gene editing, respectively, for closing important gaps in our knowledge of the function of specific genes and proteins, and the biology of these parasites. In addition, genetic manipulation methods impact the development of novel methods of control of the diseases caused by these economically important parasites. Transient and stable transfection methods, in conjunction with whole and deep genome sequencing, were initially instrumental in improving our understanding of the molecular biology of apicomplexan parasites and paved the way for the application of the more recently developed gene editing methods. The increasingly efficient and more recently developed gene editing methods, in particular those based on the CRISPR/Cas9 system and previous conceptually similar techniques, are already contributing to additional gene function discovery using reverse genetics and related approaches. However, gene editing methods are only possible due to the increasing availability of in vitro culture, transfection, and genome sequencing and analysis techniques. We envisage that rapid progress in the development of novel gene editing techniques applied to apicomplexan parasites of veterinary interest will ultimately lead to the development of novel and more efficient methods for disease control. Published by Elsevier Ltd.

How have fisheries affected parasite communities?

USGS Publications Warehouse

Wood, Chelsea L.; Lafferty, Kevin D.

2015-01-01

To understand how fisheries affect parasites, we conducted a meta-analysis of studies that contrasted parasite assemblages in fished and unfished areas. Parasite diversity was lower in hosts from fished areas. Larger hosts had a greater abundance of parasites, suggesting that fishing might reduce the abundance of parasites by selectively removing the largest, most heavily parasitized individuals. After controlling for size, the effect of fishing on parasite abundance varied according to whether the host was fished and the parasite's life cycle. Parasites of unfished hosts were more likely to increase in abundance in response to fishing than were parasites of fished hosts, possibly due to compensatory increases in the abundance of unfished hosts. While complex life cycle parasites tended to decline in abundance in response to fishing, directly transmitted parasites tended to increase. Among complex life cycle parasites, those with fished hosts tended to decline in abundance in response to fishing, while those with unfished hosts tended to increase. However, among directly transmitted parasites, responses did not differ between parasites with and without fished hosts. This work suggests that parasite assemblages are likely to change substantially in composition in increasingly fished ecosystems, and that parasite life history and fishing status of the host are important in predicting the response of individual parasite species or groups to fishing.

Self-regulating control of parasitic loads in a fuel cell power system

NASA Technical Reports Server (NTRS)

Vasquez, Arturo (Inventor)

2011-01-01

A fuel cell power system comprises an internal or self-regulating control of a system or device requiring a parasitic load. The internal or self-regulating control utilizes certain components and an interconnection scheme to produce a desirable, variable voltage potential (i.e., power) to a system or device requiring parasitic load in response to varying operating conditions or requirements of an external load that is connected to a primary fuel cell stack of the system. Other embodiments comprise a method of designing such a self-regulated control scheme and a method of operating such a fuel cell power system.

Digitally controlled twelve-pulse firing generator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berde, D.; Ferrara, A.A.

1981-01-01

Control System Studies for the Tokamak Fusion Test Reactor (TFTR) indicate that accurate thyristor firing in the AC-to-DC conversion system is required in order to achieve good regulation of the various field currents. Rapid update and exact firing angle control are required to avoid instabilities, large eddy currents, or parasitic oscillations. The Prototype Firing Generator was designed to satisfy these requirements. To achieve the required /plus or minus/0.77/degree/firing accuracy, a three-phase-locked loop reference was designed; otherwise, the Firing Generator employs digital circuitry. The unit, housed in a standard CAMAC crate, operates under microcomputer control. Functions are performed under program control,more » which resides in nonvolatile read-only memory. Communication with CICADA control system is provided via an 11-bit parallel interface.« less

Water-Related Parasitic Diseases in China

PubMed Central

Lv, Shan; Tian, Li-Guang; Liu, Qin; Qian, Men-Bao; Fu, Qing; Steinmann, Peter; Chen, Jia-Xu; Yang, Guo-Jing; Yang, Kun; Zhou, Xiao-Nong

2013-01-01

Water-related parasitic diseases are directly dependent on water bodies for their spread or as a habitat for indispensable intermediate or final hosts. Along with socioeconomic development and improvement of sanitation, overall prevalence is declining in the China. However, the heterogeneity in economic development and the inequity of access to public services result in considerable burden due to parasitic diseases in certain areas and populations across the country. In this review, we demonstrated three aspects of ten major water-related parasitic diseases, i.e., the biology and pathogenicity, epidemiology and recent advances in research in China. General measures for diseases control and special control strategies are summarized. PMID:23685826

Beyond Symbiosis: Cleaner Shrimp Clean Up in Culture

PubMed Central

Militz, Thane A.; Hutson, Kate S.

2015-01-01

Cleaner organisms exhibit a remarkable natural behaviour where they consume ectoparasites attached to “client” organisms. While this behaviour can be utilized as a natural method of parasitic disease control (or biocontrol), it is not known whether cleaner organisms can also limit reinfection from parasite eggs and larvae within the environment. Here we show that cleaner shrimp, Lysmata amboinensis, consume eggs and larvae of a harmful monogenean parasite, Neobenedenia sp., in aquaculture. Shrimp consumed parasite eggs under diurnal (63%) and nocturnal (14%) conditions as well as infectious larvae (oncomiracidia) diurnally (26%). Furthermore, we trialled the inclusion of cleaner shrimp for preventative parasite management of ornamental fish, Pseudanthias squamipinnis, and found shrimp reduced oncomiracidia infection success of host fish by half compared to controls (held without shrimp). Fish held without cleaner shrimp exhibited pigmentation changes as a result of infection, possibly indicative of a stress response. These results provide the first empirical evidence that cleaner organisms reduce parasite loads in the environment through non-symbiotic cleaning activities. Our research findings have relevance to aquaculture and the marine ornamental trade, where cleaner shrimp could be applied for prophylaxis and control of ectoparasite infections. PMID:25706952

Motility and infectivity of Plasmodium berghei sporozoites expressing avian Plasmodium gallinaceum circumsporozoite protein.

PubMed

Tewari, Rita; Rathore, Dharmendar; Crisanti, Andrea

2005-05-01

Avian and rodent malaria sporozoites selectively invade different vertebrate cell types, namely macrophages and hepatocytes, and develop in distantly related vector species. To investigate the role of the circumsporozoite (CS) protein in determining parasite survival in different vector species and vertebrate host cell types, we replaced the endogenous CS protein gene of the rodent malaria parasite Plasmodium berghei with that of the avian parasite P. gallinaceum and control rodent parasite P. yoelii. In anopheline mosquitoes, P. berghei parasites carrying P. gallinaceum and rodent parasite P. yoelii CS protein gene developed into oocysts and sporozoites. Plasmodium gallinaceum CS expressing transgenic sporozoites, although motile, failed to invade mosquito salivary glands and to infect mice, which suggests that motility alone is not sufficient for invasion. Notably, a percentage of infected Anopheles stephensi mosquitoes showed melanotic encapsulation of late stage oocysts. This was not observed in control infections or in A. gambiae infections. These findings shed new light on the role of the CS protein in the interaction of the parasite with both the mosquito vector and the rodent host.

The most important parasites in Serbia involving the foodborne route of transmission

NASA Astrophysics Data System (ADS)

Petrović, J. M.; Prodanov-Radulović, J. Z.; Vasilev, S. D.

2017-09-01

Food can be an important route for transmission of parasites to humans. Compared to other foodborne pathogens in Serbia, foodborne (or potentially foodborne) parasites do not get the attention they undoubtedly deserve. The aim of this article is to give an overview of the most important parasitic pathogens that can be transmitted by food, and that cause disease in humans: Echinococcus, Trichinella, Taenia solium and Toxoplasma gondii. For each of these pathogens, the severity of human diseases they cause, incidence, mortality and case fatality rate among humans in Serbia as well as their prevalence in animal species in Serbia are described. Some of the described foodborne parasites can induce severe disease symptoms in humans associated with high case fatality rates, while others can cause massive outbreaks. All of the aforementioned parasites occur throughout Serbia and cause both severe public health problems and substantial economic losses in livestock production. In conclusion, the control measures of foodborne parasites certainly need to include education of farmers and improvement of veterinary sanitary measures in animal farming and animal waste control.

Impact of gastrointestinal parasitic nematodes of sheep, and the role of advanced molecular tools for exploring epidemiology and drug resistance - an Australian perspective

PubMed Central

2013-01-01

Parasitic nematodes (roundworms) of small ruminants and other livestock have major economic impacts worldwide. Despite the impact of the diseases caused by these nematodes and the discovery of new therapeutic agents (anthelmintics), there has been relatively limited progress in the development of practical molecular tools to study the epidemiology of these nematodes. Specific diagnosis underpins parasite control, and the detection and monitoring of anthelmintic resistance in livestock parasites, presently a major concern around the world. The purpose of the present article is to provide a concise account of the biology and knowledge of the epidemiology of the gastrointestinal nematodes (order Strongylida), from an Australian perspective, and to emphasize the importance of utilizing advanced molecular tools for the specific diagnosis of nematode infections for refined investigations of parasite epidemiology and drug resistance detection in combination with conventional methods. It also gives a perspective on the possibility of harnessing genetic, genomic and bioinformatic technologies to better understand parasites and control parasitic diseases. PMID:23711194

A circular analysis of chronobiology of Schistosoma japonicum cercarial emergence from hilly areas of Anhui, China.

PubMed

Su, Jing; Zhou, Feng; Lu, Da-Bing

2013-10-01

About 46 mammal species have been suspected as reservoir hosts for Schistosoma japonicum and therefore the track of the target parasites, in relation to definitive host species, may be of great importance in terms of theoretical and practical implications. The circadian rhythm of cercariae emergence, a genetically controlled behavior for parasites to adapt to their definitive hosts, may seem to be a perfect biological marker for S. japonicum. In this study, a late (or nocturnal) cercarial emergence pattern was observed on the parasites from one hilly region in Anhui of China, where rodents serve as reservoirs, and on the first generation of the parasites. Moreover, by using the circular statistics, the homogeneity of parasites in such trait was also demonstrated. All these provide evidence for the genetically controlled biological trait, which seems essential in the investigation of macro- or micro-dynamics of parasite transmission of interest. This is particularly true in the case of S. japonicum when multiple parasite isolates or strains are more likely to exist. Copyright © 2013 Elsevier Inc. All rights reserved.

Prevalence of Trichomonas vaginalis and risk factors in women treated at public health units in Brazil: a transversal study.

PubMed

Grama, Daliane Faria; Casarotti, Leonardo da Silva; Morato, Michelle Gonçalves Vilela de Andrade; Silva, Lidyane Suellen; Mendonça, Daniella Fernandes; Limongi, Jean Ezequiel; Viana, João da Costa; Cury, Márcia Cristina

2013-09-01

Studies have revealed high prevalence rates of Trichomonas vaginalis in men and women worldwide. In Brazil, where reporting is not mandatory, the true prevalence rate is unknown. This study determined the prevalence of the parasite in women attending public health units in the city of Uberlândia, Minas Gerais, Brazil, identifying possible risk factors for infection, and also compared three diagnostic techniques for detecting the parasite. Samples of vaginal secretions collected from 742 women attending public health units were analyzed by direct wet mount examination, culture and smear test. Epidemiological questionnaires were administered. Of the total of 742 samples analyzed, 19 (2.6%) tested positive for T. vaginalis. The variables significantly associated with infection were: being of black ethnicity, smoking, having knowledge about sexually transmitted diseases and presenting clinical signs. The culture method was considered the gold standard test. Although there are programs to control other sexually transmitted diseases, there are none for trichomoniasis. The results of this study indicate the presence of T. vaginalis in the female population, and points to the need for more research in Brazil to gain a better understanding of the profile and epidemiology of the parasite.

Superparasitism in the Fruit Fly Parasitoid Diachasmimorpha longicaudata (Hymenoptera: Braconidae) and the Implications for Mass Rearing and Augmentative Release

PubMed Central

Montoya, Pablo; Pérez-Lachaud, Gabriela; Liedo, Pablo

2012-01-01

Superparasitism, a strategy in which a female lays eggs in/on a previously parasitized host, was attributed in the past to the inability of females to discriminate between parasitized and non-parasitized hosts. However, superparasitism is now accepted as an adaptive strategy under specific conditions. In fruit fly parasitoids, superparasitism has mainly been studied as concerns the new association between Diachasmimorpha longicaudata (Ashmead) (Hymenoptera: Braconidae) and the Mexican fruit fly Anastrepha ludens (Loew) (Diptera: Tephritidae), wherein this phenomenon is a common occurrence in both mass rearing and field conditions. Studies of this species have shown that moderate levels of superparasitism result in a female-biased sex ratio and that both massreared and wild females superparasitize their hosts without detrimental effects on offspring demographic parameters, including longevity and fecundity. These studies suggest that superparasitism in this species is advantageous. In this paper, we review superparasitism in D. longicaudata, discuss these findings in the context of mass rearing and field releases and address the possible implications of superparasitism in programs employing augmentative releases of parasitoids for the control of fruit fly pests. PMID:26466718

40 CFR 180.1101 - Parasitic (parasitoid) and predatory insects; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2010 CFR

2010-07-01

... with good agricultural and pest control practices to control insect pests of stored raw whole grains... PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1101 Parasitic (parasitoid) and...

40 CFR 180.1101 - Parasitic (parasitoid) and predatory insects; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2012 CFR

2012-07-01

... with good agricultural and pest control practices to control insect pests of stored raw whole grains... PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1101 Parasitic (parasitoid) and...

40 CFR 180.1101 - Parasitic (parasitoid) and predatory insects; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2014 CFR

2014-07-01

... with good agricultural and pest control practices to control insect pests of stored raw whole grains... PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1101 Parasitic (parasitoid) and...

40 CFR 180.1101 - Parasitic (parasitoid) and predatory insects; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2013 CFR

2013-07-01

... with good agricultural and pest control practices to control insect pests of stored raw whole grains... PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1101 Parasitic (parasitoid) and...

40 CFR 180.1101 - Parasitic (parasitoid) and predatory insects; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2011 CFR

2011-07-01

... with good agricultural and pest control practices to control insect pests of stored raw whole grains... PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1101 Parasitic (parasitoid) and...

Rationale for Quality Assurance in Fecal Egg Monitoring of Soil-Transmitted Helminthiasis.

PubMed

Hoekendijk, David J L; Hill, Philip C; Sowerby, Stephen J

2016-09-07

Substantial investment has been made into the once "neglected" tropical disease, soil-transmitted helminthiasis, and into control programs that operate within a framework of mapping baseline disease distribution, measuring the effectiveness of applied interventions, establishing when to cease drug administration, and for posttreatment evaluations. However, critical to each of these stages is the determination of helminth infection. The limitations of traditional microscope-based fecal egg diagnostics have not provided quality assurance in the monitoring of parasite disease and suboptimal treatment regimes provide for the potential development of parasite resistance to anthelmintic drugs. Improved diagnostic and surveillance tools are required to protect therapeutic effectiveness and to maintain funder confidence. Such tools may be on the horizon with emergent technologies that offer potential for enhanced visualization and quality-assured quantitation of helminth eggs. © The American Society of Tropical Medicine and Hygiene.

Advances in the application of genetic manipulation methods to apicomplexan parasites

USDA-ARS?s Scientific Manuscript database

Apicomplexan parasites such as Babesia, Theileria, Cryptosporidium, and Toxoplasma have a high negative impact on animal health globally, and improved, cost-effective measures to control them are urgently required. These parasites have complex multi-stage life cycles including obligate intracellular...

When parasites become prey: ecological and epidemiological significance of eating parasites

USGS Publications Warehouse

Johnson, Pieter T.J.; Dobson, Andrew P.; Lafferty, Kevin D.; Marcogliese, David J.; Memmott, Jane; Orlofske, Sarah A.; Poulin, Robert; Thieltges, David W.

2010-01-01

Recent efforts to include parasites in food webs have drawn attention to a previously ignored facet of foraging ecology: parasites commonly function as prey within ecosystems. Because of the high productivity of parasites, their unique nutritional composition and their pathogenicity in hosts, their consumption affects both food-web topology and disease risk in humans and wildlife. Here, we evaluate the ecological, evolutionary and epidemiological significance of feeding on parasites, including concomitant predation, grooming, predation on free-living stages and intraguild predation. Combining empirical data and theoretical models, we show that consumption of parasites is neither rare nor accidental, and that it can sharply affect parasite transmission and food web properties. Broader consideration of predation on parasites will enhance our understanding of disease control, food web structure and energy transfer, and the evolution of complex life cycles.

Canine and feline parasitic zoonoses in China

PubMed Central

2012-01-01

Canine and feline parasitic zoonoses have not been given high priority in China, although the role of companion animals as reservoirs for zoonotic parasitic diseases has been recognized worldwide. With an increasing number of dogs and cats under unregulated conditions in China, the canine and feline parasitic zoonoses are showing a trend towards being gradually uncontrolled. Currently, canine and feline parasitic zoonoses threaten human health, and cause death and serious diseases in China. This article comprehensively reviews the current status of major canine and feline parasitic zoonoses in mainland China, discusses the risks dogs and cats pose with regard to zoonotic transmission of canine and feline parasites, and proposes control strategies and measures. PMID:22839365

Towards sustainable parasite control practices in livestock production with emphasis in Latin America.

PubMed

Henrioud, A Nari

2011-08-04

Endo and ectoparasites of domestic ruminants directly or indirectly contribute to reduce sustainability affecting food security in subsistence or small scale farming systems, food safety (food borne diseases and pesticide residues), environment (pesticides, pollution and ecotoxicity) and farmer's equity (limited or uneven access to relevant technical information/training). This is especially true for some regions of Latin America where there still are huge areas of natural grazing land for cattle, sheep and goats. Sustainable parasite control is not an absolute concept given the different regions and productive systems of the world and therefore, could have different levels of adoption and impact on farmers. This article develops a conceptual framework to better understand where each region or country is situated in terms of attaining a reasonable increase in animal production while preserving sustainability. Within this context the capacity to prioritize the target parasite species for control according to local epidemiology and production systems, the early diagnosis and monitoring of parasite resistance as well as the availability of well trained field professionals acquire a major role, creating an enabling environment for present and future decision support system approaches. Until new and different means of controlling parasites become available; the challenge is to utilize Good Animal Husbandry Practices and Integrated Parasite Management (IPM) principles in a pragmatic way allowing the rational use of pesticides. Copyright © 2011 Elsevier B.V. All rights reserved.

A Comprehensive Review of Common Bacterial, Parasitic and Viral Zoonoses at the Human-Animal Interface in Egypt

PubMed Central

El-Adawy, Hosny; Abdelwhab, Elsayed M.

2017-01-01

Egypt has a unique geographical location connecting the three old-world continents Africa, Asia and Europe. It is the country with the highest population density in the Middle East, Northern Africa and the Mediterranean basin. This review summarizes the prevalence, reservoirs, sources of human infection and control regimes of common bacterial, parasitic and viral zoonoses in animals and humans in Egypt. There is a gap of knowledge conerning the epidemiology of zoonotic diseases at the human-animal interface in different localities in Egypt. Some zoonotic agents are “exotic” for Egypt (e.g., MERS-CoV and Crimean-Congo hemorrhagic fever virus), others are endemic (e.g., Brucellosis, Schistosomiasis and Avian influenza). Transboundary transmission of emerging pathogens from and to Egypt occurred via different routes, mainly importation/exportation of apparently healthy animals or migratory birds. Control of the infectious agents and multidrug resistant bacteria in the veterinary sector is on the frontline for infection control in humans. The implementation of control programs significantly decreased the prevalence of some zoonoses, such as schistosomiasis and fascioliasis, in some localities within the country. Sustainable awareness, education and training targeting groups at high risk (veterinarians, farmers, abattoir workers, nurses, etc.) are important to lessen the burden of zoonotic diseases among Egyptians. There is an urgent need for collaborative surveillance and intervention plans for the control of these diseases in Egypt. PMID:28754024

A Comprehensive Review of Common Bacterial, Parasitic and Viral Zoonoses at the Human-Animal Interface in Egypt.

PubMed

Helmy, Yosra A; El-Adawy, Hosny; Abdelwhab, Elsayed M

2017-07-21

Egypt has a unique geographical location connecting the three old-world continents Africa, Asia and Europe. It is the country with the highest population density in the Middle East, Northern Africa and the Mediterranean basin. This review summarizes the prevalence, reservoirs, sources of human infection and control regimes of common bacterial, parasitic and viral zoonoses in animals and humans in Egypt. There is a gap of knowledge conerning the epidemiology of zoonotic diseases at the human-animal interface in different localities in Egypt. Some zoonotic agents are "exotic" for Egypt (e.g., MERS-CoV and Crimean-Congo hemorrhagic fever virus), others are endemic (e.g., Brucellosis, Schistosomiasis and Avian influenza). Transboundary transmission of emerging pathogens from and to Egypt occurred via different routes, mainly importation/exportation of apparently healthy animals or migratory birds. Control of the infectious agents and multidrug resistant bacteria in the veterinary sector is on the frontline for infection control in humans. The implementation of control programs significantly decreased the prevalence of some zoonoses, such as schistosomiasis and fascioliasis, in some localities within the country. Sustainable awareness, education and training targeting groups at high risk (veterinarians, farmers, abattoir workers, nurses, etc.) are important to lessen the burden of zoonotic diseases among Egyptians. There is an urgent need for collaborative surveillance and intervention plans for the control of these diseases in Egypt.

Parasitic outbreak of the copepod Balaenophilus manatorum in neonate loggerhead sea turtles (Caretta caretta) from a head-starting program.

PubMed

Crespo-Picazo, J L; García-Parraga, D; Domènech, F; Tomás, J; Aznar, F J; Ortega, J; Corpa, J M

2017-06-02

Diseases associated to external parasitosis are scarcely reported in sea turtles. During the last decades several organism have been documented as a part of normal epibiont community connected to sea turtles. The copepod Balaenophilus manatorum has been cited as a part of epibiont fauna with some concern about its parasitic capacity. This study serves three purposes, i.e. (i) it sheds light on the type of life style that B. manatorum has developed with its hosts, particularly turtles; (ii) it makes a cautionary note of the potential health risks associated with B. manatorum in sea turtles under captivity conditions and in the wild, and (iii) it provides data on effective treatments against B. manatorum. We report for the first time a massive infestation of the copepod B. manatorum and subsequent acute mortality in a group of loggerhead sea turtle hatchlings. Four-month-old turtles from a head-starting program started exhibiting excitatory and fin rubbing behavior preceding an acute onset of lethargy, skin ulceration and death in some animals. All the individuals (n = 57) were affected by severe copepod load and presented different degrees of external macroscopic skin lesions. The ventral area of front flippers, axillar and pericloacal skin were mostly affected, and were the main parasite distribution regions. Copepods were also detected on plastron and carapace sutures. The gut contents of B. manatorum reacted positively for cytokeratin, indicating consumption of turtle skin. Severe ulcerative necrotic dermatitis and large amount of bacteria presence were the major histopathological findings. Individual fresh water immersion for 10 min and lufenuron administration (0.1 ppm) to the water system every 2 weeks proved effective for removing turtle parasites and to control re-infestation, respectively. The results from our study clearly indicated that B. manatorum individuals consume turtle skin. The pathological effects of this agent and the potential implications in sea turtle conservation and management are discussed.

High forage quality helps maintain resilience to gastrointestinal parasites on sheep and goats

USDA-ARS?s Scientific Manuscript database

Control of gastrointestinal (GI) parasites (especially the blood feeder Haemonchus contortus) in small ruminants is a problem for sheep and goat producers. Gastrointestinal parasite overloads reduce livestock performance and production efficiency, and can result in increased death losses of animals...

Regional parasite density in the skin of dogs with symptomatic canine leishmaniosis.

PubMed

Saridomichelakis, Manolis N; Koutinas, Alexander F; Olivry, Thierry; Dunston, Stan M; Farmaki, Rania; Koutinas, Christos K; Petanides, Theodoros

2007-08-01

In canine leishmaniosis, the parasitic density of the skin may be important for the infection of sandflies, and increased accumulation of inflammatory cells infected with Leishmania is believed to occur in dermal areas subjected to mechanical trauma. Parasite density and inflammatory responses in the upper and lower dermis of three body sites: flank (control site), dorsal muzzle (sandfly feeding site), and footpads (mechanical stress sites) were thus investigated in 15 dogs with symptomatic leishmaniosis. Parasite density did not differ between the control and tested sites or between the upper and lower dermis, apart from the footpads where it was higher in the upper dermis, and there was no correlation with severity of the macroscopic lesions or inflammatory infiltrate, except for the lower footpad dermis. No selective accumulation of the parasite in the muzzle that would favour its transmission to sandflies occurred, and the mechanical stress imposed on the footpads was not associated with increased parasitic density, or with inflammatory infiltrate.

Identification of opportunistic enteric parasites among immunocompetent patients with diarrhoea from Northern India and genetic characterisation of Cryptosporidium and Microsporidia.

PubMed

Ghoshal, U; Dey, A; Ranjan, P; Khanduja, S; Agarwal, V; Ghoshal, U C

2016-01-01

Enteric parasitic infestation is a major public health problem in developing countries. Parasites such as Cryptosporidium spp., Cyclospora spp., Cystoisospora spp. and Microsporidia may cause severe diarrhoea among immunocompromised patients. There is scanty data on their frequency among immunocompetent patients. Accordingly, we studied the frequency of enteric opportunistic parasites among immunocompetent patients with diarrhoea from northern India; we also performed genetic characterisation of Cryptosporidia and Microsporidia among them. Stool samples from 80 immunocompetent patients with diarrhoea, and 110 healthy controls were examined. Parasites were detected by direct microscopy, modified acid-fast (Kinyoun's) and modified trichrome stain. Polymerase chain reaction--restriction fragment length polymorphism was used for genetic characterisation of selected species such as Cryptosporidia and Microsporidia. Enteric parasites were detected in 16/80 (20%) patients (mean age 28.8±20 years, 45, 56% males) and in 2/110 (1.8%) healthy controls (P=0.00007). Parasites detected were Cryptosporidium spp. (8/16, 50.0%), Cystoisospora spp. (4/16, 25%), Microsporidia (1/16, 6.25%), Cyclospora spp. (1/16, 6.25%) and Giardia spp. (1/16, 6.25%). One patient had mixed infection with Cystoisospora spp. and Giardia spp. The species of Cryptosporidia and Microsporidia detected were Cryptosporidium hominis and Enterocytozoon bieneusi, respectively. Parasites were more often detected in younger patients (≤20 years of age) than in older. Most of the parasite infected patients presented with chronic diarrhoea. Opportunistic enteric parasitic infestation was more common among immunocompetent patients with diarrhoea than healthy subjects. Special staining as well as molecular methods are essential for appropriate diagnosis of these parasites.

Reduced erythrocyte susceptibility and increased host clearance of young parasites slows Plasmodium growth in a murine model of severe malaria

NASA Astrophysics Data System (ADS)

Khoury, David S.; Cromer, Deborah; Best, Shannon E.; James, Kylie R.; Sebina, Ismail; Haque, Ashraful; Davenport, Miles P.

2015-05-01

The best correlate of malaria severity in human Plasmodium falciparum (Pf) infection is the total parasite load. Pf-infected humans could control parasite loads by two mechanisms, either decreasing parasite multiplication, or increasing parasite clearance. However, few studies have directly measured these two mechanisms in vivo. Here, we have directly quantified host clearance of parasites during Plasmodium infection in mice. We transferred labelled red blood cells (RBCs) from Plasmodium infected donors into uninfected and infected recipients, and tracked the fate of donor parasites by frequent blood sampling. We then applied age-based mathematical models to characterise parasite clearance in the recipient mice. Our analyses revealed an increased clearance of parasites in infected animals, particularly parasites of a younger developmental stage. However, the major decrease in parasite multiplication in infected mice was not mediated by increased clearance alone, but was accompanied by a significant reduction in the susceptibility of RBCs to parasitisation.

Alternative approaches for the control of gastrointestinal nematodes in sheep farming: a review.

PubMed

Šimpraga, Miljenko; Ljubičić, Iva; Hlede, Jadranka Pejaković; Vugrovečki, Ana Shek; Marinculić, Albert; Tkalčić, Suzana

2015-01-01

Gastrointestinal nematodes (GIN) are a serious health problem and represent the most significant constraint in sheep grazing operations. Problems tend to be worse in organic sheep farming systems, as a consequence of a less restricted access of animals to outdoor environment with a higher exposure to infective larvae. In domestic animals, GIN are effectively controlled by an aggressive prophylactic administration of commercially available anthelmintics. As a consequence to a common overdose and misuse of readily available antiparasitic treatments, there is an inevitable development of populations of GIN resistant to all major classes of anthelmintics. Also, the control of GIN that is based entirely on the anthelmintic use, threatens sustainability of the sheep farming worldwide. The combination of the optimized use of anthelmintic drugs and alternative approaches seem to be a reasonable choice in sustainable parasitic control programs that offer a substantial reduction of anthelmintic treatments and conservation of anthelmintic efficacy. In that aspect, a "targeted selective treatment (TST)" directed towards animals clinically diagnosed with GIN, seems to be an effective approach to leave some parasite populations unexposed to anthelmintics (refugia) and to reduce development of anthelmintic resistance. Also, many current research efforts aim to find and validate sustainable non-chemotherapeutic approaches to GIN control, including changes in grazing management, optimized nutrition, dietary supplementation, consumption of plants with anthelmintic properties, biological control by nematophagous fungi, copper oxide wire particles (COWP), and homeopathic treatments. This manuscript outlines (outlines) and discusses relevant alternative approaches for GIN control in modern sheep farming systems.

Paradigms for parasite conservation.

PubMed

Dougherty, Eric R; Carlson, Colin J; Bueno, Veronica M; Burgio, Kevin R; Cizauskas, Carrie A; Clements, Christopher F; Seidel, Dana P; Harris, Nyeema C

2016-08-01

Parasitic species, which depend directly on host species for their survival, represent a major regulatory force in ecosystems and a significant component of Earth's biodiversity. Yet the negative impacts of parasites observed at the host level have motivated a conservation paradigm of eradication, moving us farther from attainment of taxonomically unbiased conservation goals. Despite a growing body of literature highlighting the importance of parasite-inclusive conservation, most parasite species remain understudied, underfunded, and underappreciated. We argue the protection of parasitic biodiversity requires a paradigm shift in the perception and valuation of their role as consumer species, similar to that of apex predators in the mid-20th century. Beyond recognizing parasites as vital trophic regulators, existing tools available to conservation practitioners should explicitly account for the unique threats facing dependent species. We built upon concepts from epidemiology and economics (e.g., host-density threshold and cost-benefit analysis) to devise novel metrics of margin of error and minimum investment for parasite conservation. We define margin of error as the risk of accidental host extinction from misestimating equilibrium population sizes and predicted oscillations, while minimum investment represents the cost associated with conserving the additional hosts required to maintain viable parasite populations. This framework will aid in the identification of readily conserved parasites that present minimal health risks. To establish parasite conservation, we propose an extension of population viability analysis for host-parasite assemblages to assess extinction risk. In the direst cases, ex situ breeding programs for parasites should be evaluated to maximize success without undermining host protection. Though parasitic species pose a considerable conservation challenge, adaptations to conservation tools will help protect parasite biodiversity in the face of an uncertain environmental future. © 2015 Society for Conservation Biology.

Unitized Regenerative Fuel Cell System Development

NASA Technical Reports Server (NTRS)

Burke, Kenneth A.

2003-01-01

Unitized Regenerative Fuel Cells (URFC) have recently been developed by several fuel cell manufacturers. These manufacturers have concentrated their efforts on the development of the cell stack technology itself, and have not up to this point devoted much effort to the design and development of the balance of plant. A fuel cell technology program at the Glenn Research Center (GRC) that has as its goal the definition and feasibility testing of the URFC system balance of plant. Besides testing the feasibility, the program also intends to minimize the system weight, volume, and parasitic power as its goal. The design concept currently being developed uses no pumps to circulate coolant or reactants, and minimizes the ancillary components to only the oxygen and hydrogen gas storage tanks, a water storage tank, a loop heat pipe to control the temperature and two pressure control devices to control the cell stack pressures during operation. The information contained in this paper describes the design and operational concepts employed in this concept. The paper also describes the NASA Glenn research program to develop this concept and test its feasibility.

Leveraging rural energy investment for parasitic disease control: schistosome ova inactivation and energy co-benefits of anaerobic digesters in rural China.

PubMed

Remais, Justin; Chen, Lin; Seto, Edmund

2009-01-01

Cooking and heating remain the most energy intensive activities among the world's poor, and thus improved access to clean energies for these tasks has been highlighted as a key requirement of attaining the major objectives of the UN Millennium Development Goals. A move towards clean energy technologies such as biogas systems (which produce methane from human and animal waste) has the potential to provide immediate benefits for the control of neglected tropical diseases. Here, an assessment of the parasitic disease and energy benefits of biogas systems in Sichuan Province, China, is presented, highlighting how the public health sector can leverage the proliferation of rural energy projects for infectious disease control. First, the effectiveness of biogas systems at inactivating and removing ova of the human parasite Schistosoma japonicum is experimentally evaluated. Second, the impact of biogas infrastructure on energy use and environmental quality as reported by surveyed village populations is assessed, as is the community acceptance of the technology. No viable eggs were recovered in the effluent collected weekly from biogas systems for two months following seeding with infected stool. Less than 1% of ova were recovered viable from a series of nylon bags seeded with ova, a 2-log removal attributable to biochemical inactivation. More than 90% of Ascaris lumbricoides ova (used as a proxy for S. japonicum ova) counted at the influent of two biogas systems were removed in the systems when adjusted for system residence time, an approximate 1-log removal attributable to sedimentation. Combined, these inactivation/removal processes underscore the promise of biogas infrastructure for reducing parasite contamination resulting from nightsoil use. When interviewed an average of 4 years after construction, villagers attributed large changes in fuel usage to the installation of biogas systems. Household coal usage decreased by 68%, wood by 74%, and crop waste by 6%. With reported energy savings valued at roughly 600 CNY per year, 2-3 years were required to recoup the capital costs of biogas systems. In villages without subsidies, no new biogas systems were implemented. Sustainable strategies that integrate rural energy needs and sanitation offer tremendous promise for long-term control of parasitic diseases, while simultaneously reducing energy costs and improving quality of life. Government policies can enhance the financial viability of such strategies by introducing fiscal incentives for joint sanitation/sustainable energy projects, along with their associated public outreach and education programs.

Leveraging Rural Energy Investment for Parasitic Disease Control: Schistosome Ova Inactivation and Energy Co-Benefits of Anaerobic Digesters in Rural China

PubMed Central

Remais, Justin; Chen, Lin; Seto, Edmund

2009-01-01

Background Cooking and heating remain the most energy intensive activities among the world's poor, and thus improved access to clean energies for these tasks has been highlighted as a key requirement of attaining the major objectives of the UN Millennium Development Goals. A move towards clean energy technologies such as biogas systems (which produce methane from human and animal waste) has the potential to provide immediate benefits for the control of neglected tropical diseases. Here, an assessment of the parasitic disease and energy benefits of biogas systems in Sichuan Province, China, is presented, highlighting how the public health sector can leverage the proliferation of rural energy projects for infectious disease control. Methodology/Findings First, the effectiveness of biogas systems at inactivating and removing ova of the human parasite Schistosoma japonicum is experimentally evaluated. Second, the impact of biogas infrastructure on energy use and environmental quality as reported by surveyed village populations is assessed, as is the community acceptance of the technology. No viable eggs were recovered in the effluent collected weekly from biogas systems for two months following seeding with infected stool. Less than 1% of ova were recovered viable from a series of nylon bags seeded with ova, a 2-log removal attributable to biochemical inactivation. More than 90% of Ascaris lumbricoides ova (used as a proxy for S. japonicum ova) counted at the influent of two biogas systems were removed in the systems when adjusted for system residence time, an approximate 1-log removal attributable to sedimentation. Combined, these inactivation/removal processes underscore the promise of biogas infrastructure for reducing parasite contamination resulting from nightsoil use. When interviewed an average of 4 years after construction, villagers attributed large changes in fuel usage to the installation of biogas systems. Household coal usage decreased by 68%, wood by 74%, and crop waste by 6%. With reported energy savings valued at roughly 600 CNY per year, 2–3 years were required to recoup the capital costs of biogas systems. In villages without subsidies, no new biogas systems were implemented. Conclusions Sustainable strategies that integrate rural energy needs and sanitation offer tremendous promise for long-term control of parasitic diseases, while simultaneously reducing energy costs and improving quality of life. Government policies can enhance the financial viability of such strategies by introducing fiscal incentives for joint sanitation/sustainable energy projects, along with their associated public outreach and education programs. PMID:19293926

Resist Globally, Infect Locally: A Transcontinental Test of Adaptation by Stickleback and Their Tapeworm Parasite.

PubMed

Weber, Jesse N; Kalbe, Martin; Shim, Kum Chuan; Erin, Noémie I; Steinel, Natalie C; Ma, Lei; Bolnick, Daniel I

2017-01-01

Parasite infections are a product of both ecological processes affecting host-parasite encounter rates and evolutionary dynamics affecting host susceptibility. However, few studies examine natural infection variation from both ecological and evolutionary perspectives. Here, we describe the ecological and evolutionary factors generating variation in infection rates by a tapeworm (Schistocephalus solidus) in a vertebrate host, the threespine stickleback (Gasterosteus aculeatus). To explore ecological aspects of infection, we measured tapeworm prevalence in Canadian stickleback inhabiting two distinct environments: marine and freshwater. Consistent with ecological control of infection, the tapeworm is very rare in marine environments, even though marine fish are highly susceptible. Conversely, commonly infected freshwater stickleback exhibit substantial resistance in controlled laboratory trials, suggesting that high exposure risk overwhelms their recently evolved resistance. We also tested for parasite adaptation to its host by performing transcontinental reciprocal infections, using stickleback and tapeworm populations from Europe and western Canada. More infections occurred in same-continent host-parasite combinations, indicating parasite "local" adaptation, at least on the scale of continents. However, the recently evolved immunity of freshwater hosts applies to both local and foreign parasites. The pattern of adaptation described here is not wholly compatible with either of the common models of host-parasite coevolution (i.e., matching infection or targeted recognition). Instead, we propose a hybrid, eco-evolutionary model to explain the remarkable pattern of global host resistance and local parasite infectivity.

The dauer hypothesis and the evolution of parasitism: 20 years on and still going strong

PubMed Central

Crook, Matt

2013-01-01

How any complex trait has evolved is a fascinating question, yet the evolution of parasitism among the nematodes is arguably one of the most arresting. How did free-living nematodes cross that seemingly insurmountable evolutionary chasm between soil dwelling and survival inside another organism? Which of the many finely honed responses to the varied and harsh environments of free-living nematodes provided the material upon which natural selection could act? Although several complementary theories explain this phenomenon, I will focus on the dauer hypothesis. The dauer hypothesis posits that the arrested third-stage dauer larvae of free-living nematodes such as Caenorhabditis elegans are, due to their many physiological similarities with infective third-stage larvae of parasitic nematodes, a pre-adaptation to parasitism. If so, then a logical extension of this hypothesis is that the molecular pathways which control entry into and recovery from dauer formation by free-living nematodes in response to environmental cues have been co-opted to control the processes of infective larval arrest and activation in parasitic nematodes. The molecular machinery that controls dauer entry and exit is present in a wide range of parasitic nematodes. However, the developmental outputs of the different pathways are both conserved and divergent, not only between populations of C. elegans or between C. elegans and parasitic nematodes but also between different species of parasitic nematodes. Thus the picture that emerges is more nuanced than originally predicted and may provide insights into the evolution of such an interesting and complex trait. PMID:24095839

Donor CD8+ T Cells Prevent Toxoplasma gondii De-Encystation but Fail To Rescue the Exhausted Endogenous CD8+ T Cell Population

PubMed Central

Bhadra, Rajarshi; Cobb, Dustin A.

2013-01-01

Functional exhaustion of CD8+ T cells due to increased expression of inhibitory molecule PD-1 (Programmed Death-1) causes reactivation of latent disease during later phases of chronic toxoplasmosis. Onset of disease recrudescence results in decreased parasite cyst burden concomitant with parasites undergoing stage conversion from a primarily encysted, quiescent bradyzoite to a fast-replicating, highly motile tachyzoite. Thus, reduced cyst burden is one of the early hallmarks of disease recrudescence. This was further validated by depleting gamma interferon (IFN-γ), a cytokine known to control latent toxoplasmosis, in chronically infected prerecrudescent mice. Since CD8+ T cells (an important source of IFN-γ) lose their functionality during the later phases of chronic toxoplasmosis, we next examined if adoptive transfer of functional CD8+ T cells from acutely infected donors to the chronically infected prerecrudescent hosts could impede parasite de-encystation and rescue exhausted CD8+ T cells. While the transfer of immune CD8+ T cells temporarily restricted the breakdown of cysts, the exhausted endogenous CD8+ T cell population was not rescued. Over time, the donor population got deleted, resulting in parasite de-encystation and host mortality. Considering that donor CD8+ T cells fail to become long-lived, one of the cardinal features of memory CD8+ T cells, it bears the implication that memory CD8 differentiation is impaired during chronic toxoplasmosis. Moreover, our data strongly suggest that while adoptive immunotherapy can prevent parasite de-encystation transiently, reduced antigen burden in the chronic phase by itself is insufficient for rescue of exhausted CD8+ T cells. The conclusions of this study have profound ramifications in designing immunotherapeutics against chronic toxoplasmosis. PMID:23817617

Parasite control practices on pasture-based dairy farms in the Republic of Ireland.

PubMed

Bloemhoff, Yris; Danaher, Martin; Andrew Forbes; Morgan, Eric; Mulcahy, Grace; Power, Clare; Sayers, Ríona

2014-08-29

Dictyocaulus viviparus, Ostertagia ostertagi (nematode parasites), and Fasciola hepatica (trematode parasite) result in productivity losses on dairy farms and impact on animal health through clinical and sub-clinical disease. Parasite control in livestock systems is largely based on the use of chemoprophylactic agents (anthelmintics), grazing management, or a combination of both. The objective of this study was to document current parasite control measures employed by Irish dairy farmers in a predominantly pasture-based livestock system. A questionnaire survey of 312 geographically representative farmers was completed in 2009 with a follow up survey completed in 2011. Statistical analysis highlighted significant differences in chemoprophylactic usage between 2009 and 2011. In particular, an increase in the use of albendazole for both trematode (19% in 2009 to 36% in 2011) and nematode (30% in 2009 to 58% in 2011) control was observed. This was most likely due to flukicide restrictions introduced in the Republic of Ireland in 2010 for dairy animals. Logistic regression highlighted regional differences in chemoprophylactic use. Farmers in southern parts of Ireland, an area with good quality soil, less rainfall, and a higher density of dairy farms than other regions, were approximately half as likely to dose for F. hepatica and were more likely (OR>2.0) to use albendazole for both nematode and fluke control. Approximately 30% of respondents who used a chemoprophylactic treatment for nematodes, used a product which was 'unsuitable for purpose' (e.g. ivermectin for the treatment of F. hepatica), highlighting the need for increased awareness, continuing research, and regionally targeted education tools regarding optimal parasite control. Copyright © 2014 Elsevier B.V. All rights reserved.

The parasitic castration and gigantism of Lymnaea truncatula infected with the larval stages of Fasciola hepatica.

PubMed

Wilson, R A; Denison, J

1980-01-01

The shells of Lymnaea truncatula infected with the larval stages of Fasciola hepatica were significantly longer than those of comparable uninfected controls. The dry mass (tissue, shell + parasite) of the same infected snails, 56 days after infection, was approximately twice that of the controls (tissue + shell). The increased mass of infected snails was not due to a disproportionate increase in shell weight relative to tissues. Infected snails maintained at 20 degrees C had virtually ceased egg production by 21 days post-infection whereas control snails continued to lay eggs steadily for the duration of the experiment. The dry mass of snail tissue plus the cumulative dry weight of eggs produced was taken as an indication of the ability of control snails to generate biomass. Similarly the tissue mass plus cumulative egg weight and parasite weight was taken as an indication of the ability of the infected snails to generate biomass. The control and infected snails were not significantly different in this respect indicating that the gigantism of infected snails could be the result of a switch in nutrient supply from reproduction to somatic tissue growth and parasite growth. Castration was brought about 17-21 days after infection as a result of the direct consumption of the ovotestis by a proportion of the redial population. In a separate experiment it was demonstrated that a population of infected snails maintained at 20 degrees C survived as long as a similar group of control snails. The findings with this host-parasite system are discussed in relation to possible mechanisms causing castration and gigantism in other digene-snail interactions, and in relation to parasitic castration in other groups. It is concluded that the observed gigantism of infected snails is more likely to have a nutritional rather than endocrine origin.

Controlling and Coordinating Development in Vector-Transmitted Parasites

PubMed Central

Matthews, Keith R.

2013-01-01

Vector-borne parasites cause major human diseases of the developing world, including malaria, human African trypanosomiasis, Chagas disease, leishmaniasis, filariasis, and schistosomiasis. Although the life cycles of these parasites were defined over 100 years ago, the strategies they use to optimize their successful transmission are only now being understood in molecular terms. Parasites are now known to monitor their environment in both their host and vector and in response to other parasites. This allows them to adapt their developmental cycles and to counteract any unfavorable conditions they encounter. Here, I review the interactions that parasites engage in with their hosts and vectors to maximize their survival and spread. PMID:21385707

Preliminary assessment of the computer-based Taenia solium educational program 'The Vicious Worm' on knowledge uptake in primary school students in rural areas in eastern Zambia.

PubMed

Hobbs, Emma C; Mwape, Kabemba Evans; Van Damme, Inge; Berkvens, Dirk; Zulu, Gideon; Mambwe, Moses; Chembensofu, Mwelwa; Phiri, Isaac Khozozo; Masuku, Maxwell; Bottieau, Emmanuel; Devleesschauwer, Brecht; Speybroeck, Niko; Colston, Angela; Dorny, Pierre; Willingham, Arve Lee; Gabriël, Sarah

2018-03-01

The zoonotic helminth Taenia solium is endemic in Zambia, causing human (taeniasis and (neuro)cysticercosis) and pig (porcine cysticercosis) diseases with high health, social and economic burdens. We aimed to evaluate the impact of a health educational program intended to lead to powerful and cumulative improvements in knowledge, attitudes and practices that decrease parasite transmission and disease occurrence. Half-day health education workshops were conducted in three primary schools in the highly endemic Eastern Province of Zambia, using the computer-based T. solium educational program 'The Vicious Worm'. Questionnaires were administered before and after the educational component to determine the program's impact on knowledge uptake in primary school students. In total, 99 students participated: 38 males and 61 females, with a median age of 14 years (range 10-18 years). Baseline general knowledge of T. solium, including awareness of the different human and pig disease states, and disease diagnosis, treatment and prevention, was quite high (average score 62%) and consistent across all three study areas. Participants' knowledge had significantly increased after the educational component, particularly regarding parasite transmission and disease prevention. Preliminary assessment of 'The Vicious Worm' indicates it is an effective tool for the short-term T. solium education of primary school students in Zambia. Follow-up studies are planned to assess the longer term impact of the program on knowledge uptake in the study neighbourhoods. Inclusion of tailored 'The Vicious Worm' educational workshops should be considered in integrated cysticercosis control programs in endemic areas of sub-Saharan Africa. © 2018 The Authors. Tropical Medicine & International Health Published by John Wiley & Sons Ltd.

The Beringian Coevolution Project: Holistic collections of mammals and associated parasites reveal novel perspectives on changing environments in the north

USDA-ARS?s Scientific Manuscript database

The Beringian Coevolution Project (BCP), a field program underway in the Arctic since 1999, has focused on building key scientific infrastructure for integrated specimen-based studies on mammals and their associated parasites. BCP has contributed new insights across temporal and spatial scales into...

Infection in the Classroom: Parasites as Models to Teach Biology

ERIC Educational Resources Information Center

Seville, R. Scott; Couch, Lee; Seed, Richard; Chappell, Cynthia; Patton, Sharon

2004-01-01

The American Society of Parasitologists established a five-year plan to educate various groups about parasites and parasitology, which were targeted at K-12 students and teachers, college students and teachers and biologists in other disciplines. This program also developed the idea to host a symposium and workshop for these targeted groups.

"Koko et les lunettes magiques": An educational entertainment tool to prevent parasitic worms and diarrheal diseases in Côte d'Ivoire.

PubMed

Essé, Clémence; Koffi, Véronique A; Kouamé, Abel; Dongo, Kouassi; Yapi, Richard B; Moro, Honorine M; Kouakou, Christiane A; Palmeirim, Marta S; Bonfoh, Bassirou; N'Goran, Eliézer K; Utzinger, Jürg; Raso, Giovanna

2017-09-01

Integrated control programs, emphasizing preventive chemotherapy along with health education, can reduce the incidence of soil-transmitted helminthiasis and schistosomiasis. The aim of this study was to develop an educational animated cartoon to improve school children's awareness regarding soil-transmitted helminthiasis, diarrheal diseases, and related hygiene practices in Côte d'Ivoire. The key messages included in the cartoon were identified through prior formative research to specifically address local knowledge gaps. In a first step, preliminary research was conducted to assess the knowledge, attitudes, practices, and beliefs of school-aged children regarding parasitic worm infections and hygiene, to identify key health messages to be included in an animated cartoon. Second, an animated cartoon was produced, which included the drafting of the script and story board, and the production of the cartoon's initial version. Finally, the animated cartoon was pilot tested in eight selected schools and further fine-tuned. According to the questionnaire results, children believed that the consumption of sweet food, eating without washing their hands, sitting on the floor, and eating spoiled food were the main causes of parasitic worm infections. Abdominal pain, diarrhea, lack of appetite, failure to grow, and general fatigue were mentioned as symptoms of parasitic worm infections. Most of the children knew that they should go to the hospital for treatment if they experienced symptoms of parasitic worm diseases. The animated cartoon titled "Koko et les lunettes magiques" was produced by Afrika Toon, in collaboration with a scientific team composed of epidemiologists, civil engineers, and social scientists, and the local school children and teachers. Pilot testing of the animated cartoon revealed that, in the short term, children grasped and kept key messages. Most of the children who were shown the cartoon reported to like it. Acceptance of the animated cartoon was high among children and teachers alike. The messaging was tailored to improve knowledge and practices for prevention of helminthiases and diarrheal diseases through prior identification of knowledge gaps. Integration of such education tools into the school curriculum, along with deworming campaigns, might improve sustainability of control and elimination efforts against helminthiases and diarrheal diseases.

Molecular Detection of Plasmodium malariae/Plasmodium brasilianum in Non-Human Primates in Captivity in Costa Rica

PubMed Central

Fuentes-Ramírez, Alicia; Jiménez-Soto, Mauricio; Castro, Ruth; Romero-Zuñiga, Juan José

2017-01-01

One hundred and fifty-two blood samples of non-human primates of thirteen rescue centers in Costa Rica were analyzed to determine the presence of species of Plasmodium using thick blood smears, semi-nested multiplex polymerase chain reaction (SnM-PCR) for species differentiation, cloning and sequencing for confirmation. Using thick blood smears, two samples were determined to contain the Plasmodium malariae parasite, with SnM-PCR, a total of five (3.3%) samples were positive to P. malariae, cloning and sequencing confirmed both smear samples as P. malariae. One sample amplified a larger and conserved region of 18S rDNA for the genus Plasmodium and sequencing confirmed the results obtained microscopically and through SnM-PCR tests. Sequencing and construction of a phylogenetic tree of this sample revealed that the P. malariae/P. brasilianum parasite (GenBank KU999995) found in a howler monkey (Alouatta palliata) is identical to that recently reported in humans in Costa Rica. The SnM-PCR detected P. malariae/P. brasilianum parasite in different non-human primate species in captivity and in various regions of the southern Atlantic and Pacific coast of Costa Rica. The similarity of the sequences of parasites found in humans and a monkey suggests that monkeys may be acting as reservoirs of P.malariae/P. brasilianum, for which reason it is important, to include them in control and eradication programs. PMID:28125696

Assessing the burden of intestinal parasites affecting newly arrived immigrants in Qatar.

PubMed

Abu-Madi, Marawan A; Behnke, Jerzy M; Ismail, Ahmed; Boughattas, Sonia

2016-12-01

In the last decades, the enormous influx of immigrants to industrialized countries has led to outbreaks of parasitic diseases, with enteric infections being amongst the most frequently encountered. In its strategy to control such infection, Qatar has established the Pre-Employment Certificate (PEC) program which requires medical inspection before arrival in Qatar and which is mandatory for immigrant workers travelling to the country. To assess the reliability of the PEC, we conducted a survey of intestinal parasites, based on examination of stool samples provided by immigrant workers (n = 2,486) recently arrived in Qatar. Overall prevalence of helminths was 7.0% and that of protozoa was 11.7%. Prevalence of combined helminths was highest among the western Asians and the highest prevalence of combined protozoan parasites was among workers from North to Saharan Africa. Analysis of temporal changes showed an increasing trend of protozoan infections over the investigated 3 years. A major contribution to this temporal change in prevalence came from Blastocystis hominis as well as from other protozoan species: Giardia duodenalis and Endolimax nana. Analysis of the temporal trend in species richness of the protozoan species showed a significant increase in the mean number of species harboured per subject across this period. The increase of protozoan infections over recent years raises some concerns. It suggests that screening protocols for applicants for visas/work permits needs to be revised giving more careful attention to the intestinal protozoan infections that potential immigrants may harbor.

How do humans affect wildlife nematodes?

USGS Publications Warehouse

Weinstein, Sara B.; Lafferty, Kevin D.

2015-01-01

Human actions can affect wildlife and their nematode parasites. Species introductions and human-facilitated range expansions can create new host–parasite interactions. Novel hosts can introduce parasites and have the potential to both amplify and dilute nematode transmission. Furthermore, humans can alter existing nematode dynamics by changing host densities and the abiotic conditions that affect larval parasite survival. Human impacts on wildlife might impair parasites by reducing the abundance of their hosts; however, domestic animal production and complex life cycles can maintain transmission even when wildlife becomes rare. Although wildlife nematodes have many possible responses to human actions, understanding host and parasite natural history, and the mechanisms behind the changing disease dynamics might improve disease control in the few cases where nematode parasitism impacts wildlife.

From a lifestyle revolution in a small village in Japan. Interview [with Chojiro Kunii].

PubMed

1990-10-01

In this interview, Chojiro Kunii, JOICFP chairman and president of the Japan Family Planning Organization (JFPA), addresses the status of family planning in Japan and the world, and explains how a people-oriented approach can make family planning effective - evident from the successful Integrated Family Planning, Nutrition and Parasite-Control Project (IP). According to Chojiro, poverty and social instability in Japan shortly after World War II forced many women to resort to illegal abortions. But beginning in the early 1950s, the government introduced family planning, and by the middle of the decade, population growth had ceased to be a problem. On the contrary, by the 1960s, worries centered around labor shortages and an aging population, which some blamed on family planning. Chojiro, however, defends family planning, since its focus in on maternal and child health. For family planning worldwide, one of the most pressing issues is adolescent sex, and Chojiro says that the JFPA has begun conducting research on the subject. As far as the approach towards family planning, Chojiro stresses the importance of a people-oriented, humanistic strategy. He says that the World Population Conference held in Bucharest, Romania is an example of an inhumane approach. Many of the speakers focuses only on reducing birth rates, and not on reducing infant mortality rates. Besides, a people oriented approach can be extremely effective, evident from the Integrated Family Planning, Nutrition and Parasite-Control Project. Chojiro first introduced the idea of combining family planning and parasite control in Japan; since then, JOICFP has helped other countries develop similar programs. Finally, Chojiro points out the need for international cooperation in promoting family planning.

76 FR 81806 - Ophthalmic and Topical Dosage Form New Animal Drugs; Ivermectin Topical Solution

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-29

... effectiveness against various species of external and internal parasites when cattle are treated with a topical... control infestations of certain species of external and internal parasites. The supplemental ANADA adds claims for persistent effectiveness against various species of external and internal parasites that were...

Genetic parameters for fecal egg counts and their relationship with body weights in Katahdin lambs

USDA-ARS?s Scientific Manuscript database

Reliance on anthelminthic drugs to control internal parasites in sheep is no longer sustainable because of the development of resistance to these drugs in parasite populations. Genetic selection may offer an alternative long-term solution, as differences in parasite resistance exist both within and ...

Information and Guidelines for Identification of Children with Parasitic Intestinal Infections.

ERIC Educational Resources Information Center

Doi, Lorraine

This report presents (1) information on the incidence, causes, development, transmission, control and prevention of parasitic infections and (2) a report of how Hawaiian Follow Through Students infected by parasites were identified and provided with treatment. The students were enrolled in kindgergarten through third grade classes at three…

Reliable enumeration of malaria parasites in thick blood films using digital image analysis.

PubMed

Frean, John A

2009-09-23

Quantitation of malaria parasite density is an important component of laboratory diagnosis of malaria. Microscopy of Giemsa-stained thick blood films is the conventional method for parasite enumeration. Accurate and reproducible parasite counts are difficult to achieve, because of inherent technical limitations and human inconsistency. Inaccurate parasite density estimation may have adverse clinical and therapeutic implications for patients, and for endpoints of clinical trials of anti-malarial vaccines or drugs. Digital image analysis provides an opportunity to improve performance of parasite density quantitation. Accurate manual parasite counts were done on 497 images of a range of thick blood films with varying densities of malaria parasites, to establish a uniformly reliable standard against which to assess the digital technique. By utilizing descriptive statistical parameters of parasite size frequency distributions, particle counting algorithms of the digital image analysis programme were semi-automatically adapted to variations in parasite size, shape and staining characteristics, to produce optimum signal/noise ratios. A reliable counting process was developed that requires no operator decisions that might bias the outcome. Digital counts were highly correlated with manual counts for medium to high parasite densities, and slightly less well correlated with conventional counts. At low densities (fewer than 6 parasites per analysed image) signal/noise ratios were compromised and correlation between digital and manual counts was poor. Conventional counts were consistently lower than both digital and manual counts. Using open-access software and avoiding custom programming or any special operator intervention, accurate digital counts were obtained, particularly at high parasite densities that are difficult to count conventionally. The technique is potentially useful for laboratories that routinely perform malaria parasite enumeration. The requirements of a digital microscope camera, personal computer and good quality staining of slides are potentially reasonably easy to meet.

Are herbicide-resistant crops the answer to controlling Cuscuta?

PubMed

Nadler-Hassar, Talia; Shaner, Dale L; Nissen, Scott; Westra, Phill; Rubin, Baruch

2009-07-01

Herbicide-resistant crop technology could provide new management strategies for the control of parasitic plants. Three herbicide-resistant oilseed rape (Brassica napus L.) genotypes were used to examine the response of attached Cuscuta campestris Yuncker to glyphosate, imazamox and glufosinate. Cuscata campestris was allowed to establish on all oilseed rape genotypes before herbicides were applied. Unattached seedlings of C. campestris, C. subinclusa Durand & Hilg. and C. gronovii Willd. were resistant to imazamox and glyphosate and sensitive to glufosinate, indicating that resistance initially discovered in C. campestris is universal to all Cuscuta species. Glufosinate applied to C. campestris attached to glufosinate-resistant oilseed rape had little impact on the parasite, while imazamox completely inhibited C. campestris growth on the imidazolinone-resistant host. The growth of C. campestris on glyphosate-resistant host was initially inhibited by glyphosate, but the parasite recovered and resumed growth within 3-4 weeks. The ability of C. campestris to recover was related to the quality of interaction between the host and parasite and to the resistance mechanism of the host. The parasite was less likely to recover when it had low compatibility with the host, indicating that parasite-resistant crops coupled with herbicide resistance could be highly effective in controlling Cuscuta. (c) 2009 by John Wiley & Sons, Ltd.

Guidelines for zoo and aquarium veterinary medical programs and veterinary hospitals.

PubMed

Backues, Kay; Clyde, Vickie; Denver, Mary; Fiorello, Christine; Hilsenroth, Rob; Lamberski, Nadine; Larson, Scott; Meehan, Tom; Murray, Mike; Ramer, Jan; Ramsay, Ed; Suedmeyer, Kirk; Whiteside, Doug

2011-03-01

These guidelines for veterinary medical care and veterinary hospitals are written to conform with the requirements of the Animal Welfare Act, which states that programs of disease prevention and parasite control, euthanasia, and adequate veterinary care shall be established and maintained under the supervision of a veterinarian. Ideally the zoo and aquarium should be providing the best possible veterinary medical care for the animals in their collections. Many of these animals are rare and endangered and the institutions should endeavor both to provide for the long term health and well being of these animals and to advance the field of non-domestic animal medicine. It is hoped that this publication will aid in this process.

Application of small RNA technology for improved control of parasitic helminths.

PubMed

Britton, Collette; Winter, Alan D; Marks, Neil D; Gu, Henry; McNeilly, Tom N; Gillan, Victoria; Devaney, Eileen

2015-08-15

Over the last decade microRNAs (miRNAs) and small interfering RNAs (siRNAs) have emerged as important regulators of post-transcriptional gene expression. miRNAs are short, non-coding RNAs that regulate a variety of processes including cancer, organ development and immune function. This class of small RNAs bind with partial complementarity to their target mRNA sequences, most often in the 3'UTR, to negatively regulate gene expression. In parasitic helminths, miRNAs are being increasingly studied for their potential roles in development and host-parasite interactions. The availability of genome data, combined with small RNA sequencing, has paved the way to profile miRNAs expressed at particular developmental stages for many parasitic helminths. While some miRNAs are conserved across species, others appear to be unique to specific parasites, suggesting important roles in adaptation and survival in the host environment. Some miRNAs are released from parasites, in exosomes or in protein complexes, and the potential effects of these on host immune function are being increasingly studied. In addition, release of miRNAs from schistosome and filarial parasites into host plasma can be exploited for the development of specific and sensitive diagnostic biomarkers of infection. Interfering with miRNA function, as well as silencing key components of the pathways they regulate, will progress our understanding of parasite development and provide a novel approach to therapeutic control. RNA interference (RNAi) by siRNAs has proven to be inconsistent in parasitic nematodes. However, the recent successes reported for schistosome and liver fluke RNAi, encourage further efforts to enhance delivery of RNA and improve in vitro culture systems and assays to monitor phenotypic effects in nematodes. These improvements are important for the establishment of reliable functional genomic platforms for novel drug and vaccine development. In this review we focus on the important roles of miRNAs and siRNAs in post-transcriptional gene regulation in veterinary parasitic helminths and the potential value of these in parasite diagnosis and control. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

My university. What I learned from the Productive Cooperative Movement to Promotion of Humanistic Family Planning.

PubMed

Kunii, C

1990-07-01

Based on experiences with the Productive Cooperative Movement and the Parasite Control Movement in Japan, the Japanese Family Planning Movement began in April 1954. The resultant private and nonprofit Japan Family Planning Association (JFPA) followed and it served to help Japan achieve its goal of reducing fertility by promoting family planning. It did so by publishing a monthly newsletter on family planning, hosting meetings and national conventions, spreading information via the mass media, and selling contraceptives and educational materials. JFPA earned funding from these sales with no support from the government thereby establishing self dependence and freedom to speak candidly to the government. The JFPA learned that families wanted to improve their standard of living and were willing to limit family size to 2 children. After the birth rate peaked in 1955, the birth rate and the number of illegal abortions decreased. In the 1950s, JFPA joined the International Planned Parenthood Federation and subsequently learned of the problems faced by developing countries. Based on the successful reduction of fertility in Japan and a strong economic base, JFPA and the government were in a position to organize an international cooperation program for family planning. Therefore, the leader of JFPA resigned to found the Japanese Organization for International Cooperation in Family Planning which promotes family planning in developing countries via its integrated family planning, nutrition, and parasite control program. A steering committee composed of leaders from government, universities, and private organizations sets the policies for the program in each country. It is to the Japanese government's advantage to work with private organizations instead of providing all social services because they are flexible and provide administrative stability and national expenses are minimized.

Culinary delights and travel? A review of zoonotic cestodiases and metacestodiases.

PubMed

Ito, Akira; Budke, Christine M

2014-01-01

Due to increased globalization, food-borne parasitic infections are becoming more prevalent worldwide, including in countries where these parasites and parasitic diseases had previously been well controlled or eradicated. Improved sanitation, health education, and establishment of appropriate food safety mechanisms can go a long way towards the control of many these infections. However, food-borne parasitic infections are still common diseases in developing countries, especially in rural areas. As many of today's travelers are looking to explore more distant locations and partake in the local cuisine, they may be at greater risk of acquiring a food-borne parasitic infection, including those caused by a number of adult and larval tapeworms. This review discusses fish and meat-borne tapeworms and zoonotic metacestodiases of public health importance to both developing and developed countries, with a focus on infection prevention in travelers. Copyright © 2014 Elsevier Ltd. All rights reserved.

Comparative reproductive biology of the social parasite Acromyrmex ameliae de Souza, Soares & Della Lucia and of its host Acromyrmex subterraneus subterraneus Forel (Hymenoptera: Formicidae).

PubMed

Soares, Ilka M F; Della Lucia, Terezinha M C; Pereira, Alice S; Serrão, José E; Ribeiro, Myriam M R; De Souza, Danival J

2010-01-01

Social parasites exhibit several characteristics that allow them to exploit their host species efficiently. The smaller size of parasite species is a trait commonly found in ants. In this work, we investigated several aspects of the reproductive biology of Acromyrmex ameliae De Souza, Soares & Della Lucia, a recently discovered parasite of Acromyrmex subterraneus subterraneus Forel. Sexuals of A. ameliae are substantially smaller than those from host species. Parasite queens laid significantly less worker eggs than host queens and inhibit sexual production of the host. The sex ratio of parasite species is highly female biased. Interestingly, we have observed parasite coupling on the laboratory, inside the nests and in the ground, opening the possibility to use controlled mating to study genetic approaches of parasitism in the ants.

Conflict between co-occurring manipulative parasites? An experimental study of the joint influence of two acanthocephalan parasites on the behaviour of Gammarus pulex.

PubMed

Cezilly, F; Gregoire, A; Bertin, A

2000-06-01

When two parasite species are manipulators and have different definitive hosts, there is a potential for conflict between them. Selection may then exist for either avoiding hosts infected with conflicting parasites, or for hijacking, i.e. competitive processes to gain control of the intermediate host. The evidence for both phenomena depends largely on the study of the relative competitive abilities of parasites within their common intermediate host. We studied the effects of simultaneous infection by a fish acanthocephalan parasite, Pomphorhynchus laevis, and a bird acanthocephalan parasite, Polymorphus minutus, on the behaviour of their common intermediate host, the amphipod Gammarus pulex. We compared the reaction to light and vertical distribution of individuals infected with both parasites to those of individuals harbouring a single parasite species and uninfected ones under controlled conditions. Compared to uninfected gammarids that were photophobic and tended to remain at the bottom of the water column, P. laevis-infected gammarids were attracted to light, whereas P. minutus-infected individuals showed a modified vertical distribution and were swimming closer to the water surface. The effects of both P. laevis and P. minutus appeared to be dependent only on their presence, not on their intensity. Depending on the behavioural trait under study, however, the outcome of the antagonism between P. laevis and P. minutus differed. The vertical distribution of gammarids harbouring both parasites was half-way between those of P. laevis- and P. minutus-infected individuals, whereas P. laevis was able to induce altered reaction to light even in the presence of P. minutus. We discuss our results in relation to the occurrence of active avoidance or hijacking between conflicting manipulative parasites and provide some recommendations for future research.

Optimal profit of the parasitation by Aphelinus mali in an IPM complementary strategy for the control of Eriosoma lanigerum.

PubMed

Goossens, D; Bangels, E; Belien, T; Schoevaerts, C; De Maeyer, L

2011-01-01

During summer the parasitoid Aphelinus mali may certainly reduce the infestation of woolly apple aphid (Eriosoma lanigerum), but studies on the single interaction rarely indicate sufficient biological control in the period May-June. In this period chemical control by spirotetramat or pirimicarb remains indispensable in order to anticipate on dense migration waves and subsequent colonization of extension shoots by E. lanigerum. The limited parasitation by A. mali around flowering is linked with a delayed emergence from diapause and with a slower reproduction rate than its host. In 2010 and 2011 the first adult flights monitored on yellow sticky traps corresponded perfectly with the currently used prediction models for A. mali. Further accurate monitoring all along the season enabled also to determine a well defined endo-parasitic phase of A. mali occurring after the small peak observed around flowering. During this endo-parasitic phase A. mali larvae reside inside their mummified host. Compounds with higher acute toxicity on A. mali adults, like chloronicotinyl insecticides (CNI's), are preferably positioned here. Selectivity in the time can then be claimed. Respecting this principle, the further parasitation potential of A. mali in summer is not hampered. Preservation of the first peak of flights of A. mali in the pre-flowering period is essential for an exponential flight increase. This is essential for the parasitation of E. lanigerum in summer, which constitutes a valuable complement in the integrated control strategy.

Helminth infections in domestic dogs from Russia

PubMed Central

Moskvina, T. V.; Ermolenko, A. V.

2016-01-01

Dogs are the hosts for a wide helminth spectrum including tapeworms, flatworms, and nematodes. These parasites affect the dog health and cause morbidity and mortality, especially in young and old animals. Some species, as Toxocara canis, Ancylostoma caninum, Dipylidium caninum, and Echinococcus spp. are well-known zoonotic parasites worldwide, resulting in high public health risks. Poor data about canine helminth species and prevalence are available in Russia, mainly due to the absence of official guidelines for the control of dog parasites. Moreover, the consequent low quality of veterinary monitoring and use of preventive measures, the high rate of environmental contamination by dog feces and the increase of stray dog populations, make the control of the environmental contamination by dog helminths very difficult in this country. This paper reviews the knowledge on canine helminth fauna and prevalence in Russia. Practical aspects related to diagnosis, treatment, and control of parasitic diseases of dogs in Russia are discussed. PMID:27956777

Molecular mechanisms of nematode-nematophagous microbe interactions: basis for biological control of plant-parasitic nematodes.

PubMed

Li, Juan; Zou, Chenggang; Xu, Jianping; Ji, Xinglai; Niu, Xuemei; Yang, Jinkui; Huang, Xiaowei; Zhang, Ke-Qin

2015-01-01

Plant-parasitic nematodes cause significant damage to a broad range of vegetables and agricultural crops throughout the world. As the natural enemies of nematodes, nematophagous microorganisms offer a promising approach to control the nematode pests. Some of these microorganisms produce traps to capture and kill the worms from the outside. Others act as internal parasites to produce toxins and virulence factors to kill the nematodes from within. Understanding the molecular basis of microbe-nematode interactions provides crucial insights for developing effective biological control agents against plant-parasitic nematodes. Here, we review recent advances in our understanding of the interactions between nematodes and nematophagous microorganisms, with a focus on the molecular mechanisms by which nematophagous microorganisms infect nematodes and on the nematode defense against pathogenic attacks. We conclude by discussing several key areas for future research and development, including potential approaches to apply our recent understandings to develop effective biocontrol strategies.

P. falciparum in vitro killing rates allow to discriminate between different antimalarial mode-of-action.

PubMed

Sanz, Laura M; Crespo, Benigno; De-Cózar, Cristina; Ding, Xavier C; Llergo, Jose L; Burrows, Jeremy N; García-Bustos, Jose F; Gamo, Francisco-Javier

2012-01-01

Chemotherapy is still the cornerstone for malaria control. Developing drugs against Plasmodium parasites and monitoring their efficacy requires methods to accurately determine the parasite killing rate in response to treatment. Commonly used techniques essentially measure metabolic activity as a proxy for parasite viability. However, these approaches are susceptible to artefacts, as viability and metabolism are two parameters that are coupled during the parasite life cycle but can be differentially affected in response to drug actions. Moreover, traditional techniques do not allow to measure the speed-of-action of compounds on parasite viability, which is an essential efficacy determinant. We present here a comprehensive methodology to measure in vitro the direct effect of antimalarial compounds over the parasite viability, which is based on limiting serial dilution of treated parasites and re-growth monitoring. This methodology allows to precisely determine the killing rate of antimalarial compounds, which can be quantified by the parasite reduction ratio and parasite clearance time, which are key mode-of-action parameters. Importantly, we demonstrate that this technique readily permits to determine compound killing activities that might be otherwise missed by traditional, metabolism-based techniques. The analysis of a large set of antimalarial drugs reveals that this viability-based assay allows to discriminate compounds based on their antimalarial mode-of-action. This approach has been adapted to perform medium throughput screening, facilitating the identification of fast-acting antimalarial compounds, which are crucially needed for the control and possibly the eradication of malaria.

P. falciparum In Vitro Killing Rates Allow to Discriminate between Different Antimalarial Mode-of-Action

PubMed Central

Sanz, Laura M.; Crespo, Benigno; De-Cózar, Cristina; Ding, Xavier C.; Llergo, Jose L.; Burrows, Jeremy N.; García-Bustos, Jose F.; Gamo, Francisco-Javier

2012-01-01

Chemotherapy is still the cornerstone for malaria control. Developing drugs against Plasmodium parasites and monitoring their efficacy requires methods to accurately determine the parasite killing rate in response to treatment. Commonly used techniques essentially measure metabolic activity as a proxy for parasite viability. However, these approaches are susceptible to artefacts, as viability and metabolism are two parameters that are coupled during the parasite life cycle but can be differentially affected in response to drug actions. Moreover, traditional techniques do not allow to measure the speed-of-action of compounds on parasite viability, which is an essential efficacy determinant. We present here a comprehensive methodology to measure in vitro the direct effect of antimalarial compounds over the parasite viability, which is based on limiting serial dilution of treated parasites and re-growth monitoring. This methodology allows to precisely determine the killing rate of antimalarial compounds, which can be quantified by the parasite reduction ratio and parasite clearance time, which are key mode-of-action parameters. Importantly, we demonstrate that this technique readily permits to determine compound killing activities that might be otherwise missed by traditional, metabolism-based techniques. The analysis of a large set of antimalarial drugs reveals that this viability-based assay allows to discriminate compounds based on their antimalarial mode-of-action. This approach has been adapted to perform medium throughput screening, facilitating the identification of fast-acting antimalarial compounds, which are crucially needed for the control and possibly the eradication of malaria. PMID:22383983

Experimental demonstration of the fitness consequences of an introduced parasite of Darwin's finches.

PubMed

Koop, Jennifer A H; Huber, Sarah K; Laverty, Sean M; Clayton, Dale H

2011-05-11

Introduced parasites are a particular threat to small populations of hosts living on islands because extinction can occur before hosts have a chance to evolve effective defenses. An experimental approach in which parasite abundance is manipulated in the field can be the most informative means of assessing a parasite's impact on the host. The parasitic fly Philornis downsi, recently introduced to the Galápagos Islands, feeds on nestling Darwin's finches and other land birds. Several correlational studies, and one experimental study of mixed species over several years, reported that the flies reduce host fitness. Here we report the results of a larger scale experimental study of a single species at a single site over a single breeding season. We manipulated the abundance of flies in the nests of medium ground finches (Geospiza fortis) and quantified the impact of the parasites on nestling growth and fledging success. We used nylon nest liners to reduce the number of parasites in 24 nests, leaving another 24 nests as controls. A significant reduction in mean parasite abundance led to a significant increase in the number of nests that successfully fledged young. Nestlings in parasite-reduced nests also tended to be larger prior to fledging. Our results confirm that P. downsi has significant negative effects on the fitness of medium ground finches, and they may pose a serious threat to other species of Darwin's finches. These data can help in the design of management plans for controlling P. downsi in Darwin's finch breeding populations.

Mind Control: How Parasites Manipulate Cognitive Functions in Their Insect Hosts.

PubMed

Libersat, Frederic; Kaiser, Maayan; Emanuel, Stav

2018-01-01

Neuro-parasitology is an emerging branch of science that deals with parasites that can control the nervous system of the host. It offers the possibility of discovering how one species (the parasite) modifies a particular neural network, and thus particular behaviors, of another species (the host). Such parasite-host interactions, developed over millions of years of evolution, provide unique tools by which one can determine how neuromodulation up-or-down regulates specific behaviors. In some of the most fascinating manipulations, the parasite taps into the host brain neuronal circuities to manipulate hosts cognitive functions. To name just a few examples, some worms induce crickets and other terrestrial insects to commit suicide in water, enabling the exit of the parasite into an aquatic environment favorable to its reproduction. In another example of behavioral manipulation, ants that consumed the secretions of a caterpillar containing dopamine are less likely to move away from the caterpillar and more likely to be aggressive. This benefits the caterpillar for without its ant bodyguards, it is more likely to be predated upon or attacked by parasitic insects that would lay eggs inside its body. Another example is the parasitic wasp, which induces a guarding behavior in its ladybug host in collaboration with a viral mutualist. To exert long-term behavioral manipulation of the host, parasite must secrete compounds that act through secondary messengers and/or directly on genes often modifying gene expression to produce long-lasting effects.

Health of an ex situ population of raptors (Falconiformes and Strigiformes) in Mexico: diagnosis of internal parasites.

PubMed

Santos, Tiziano; de Oliveira, Jaqueline B; Vaughan, Christopher; Santiago, Heber

2011-09-01

Successful programs for ex situ and in situ conservation and management of raptors require detailed knowledge about their pathogens. The purpose of this study was to identify the internal parasites of some captive raptors in Mexico, as well as to verify their impact in the health status of infected birds. Birds of prey were confiscated and kept in captivity at the Centro de Investigación y Conservación de Vida Silvestre (CIVS) in Los Reyes La Paz, Mexico State. For this, fecal and blood samples from 74 birds of prey (66 Falconiformes and eight Strigiformes) of 15 species, juveniles and adults from both sexes (39 males and 35 female), were examined for the presence of gastrointestinal and blood parasites. Besides, the oropharyngeal cavity was macroscopically examined for the presence of lesions compatible with trichomoniasis. Among our results we found that lesions compatible with Trichomonas gallinae infection were detected only in two Red-tailed hawks (Buteo jamaicensis) (2.7%); nevertheless, infected birds were in good physical condition. Overall, gastrointestinal parasites were found in 10 (13.5%) raptors: nine falconiforms (13.6%) and one strigiform (12.5%), which mainly presented a single type of gastrointestinal parasite (90%). Eimeria spp. was detected in Harris's hawk (Parabuteo unicinctus), Swainson's hawk (Buteo swainsoni), Red-tailed hawk (B. jamaicensis) and Great horned owl (Bubo virginianus); whereas trematodes eggs were found in Peregrine falcon (Falco peregrinus) and Swainson's hawk (B. swainsoni). Furthermore, eggs of Capillaria spp. were found in one Swainson's hawk (B. swainsoni), which was also infected by trematodes. Hemoprotozoarian were detected in five (6.7%) falconiforms: Haemoproteus spp. in American kestrel (F. sparverius) and Leucocytozoon spp. in Red-tailed hawk (B. jamaicencis). Despite this, no clinical signs referable to gastrointestinal or blood parasite infection were observed in any birds. All parasites identified were recorded for the first time in raptors from Mexico. Furthermore, this represents the first report for T. gallinae, trematodes, Haemoproteus spp. and Leucocytozoon spp. in raptors from Latin America. Diagnosis and control of parasitic infections should be a part of the routine in health care evaluations for ex situ raptor populations. Finally, this information is also valuable for in situ conservation actions on these birds.

The dauer hypothesis and the evolution of parasitism: 20 years on and still going strong.

PubMed

Crook, Matt

2014-01-01

How any complex trait has evolved is a fascinating question, yet the evolution of parasitism among the nematodes is arguably one of the most arresting. How did free-living nematodes cross that seemingly insurmountable evolutionary chasm between soil dwelling and survival inside another organism? Which of the many finely honed responses to the varied and harsh environments of free-living nematodes provided the material upon which natural selection could act? Although several complementary theories explain this phenomenon, I will focus on the dauer hypothesis. The dauer hypothesis posits that the arrested third-stage dauer larvae of free-living nematodes such as Caenorhabditis elegans are, due to their many physiological similarities with infective third-stage larvae of parasitic nematodes, a pre-adaptation to parasitism. If so, then a logical extension of this hypothesis is that the molecular pathways which control entry into and recovery from dauer formation by free-living nematodes in response to environmental cues have been co-opted to control the processes of infective larval arrest and activation in parasitic nematodes. The molecular machinery that controls dauer entry and exit is present in a wide range of parasitic nematodes. However, the developmental outputs of the different pathways are both conserved and divergent, not only between populations of C. elegans or between C. elegans and parasitic nematodes but also between different species of parasitic nematodes. Thus the picture that emerges is more nuanced than originally predicted and may provide insights into the evolution of such an interesting and complex trait. Copyright © 2013 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

Cryptosporidiosis and other intestinal parasitic infections in patients with chronic diarrhea.

PubMed

Mahdi, Nadham K; Ali, Naeel H

2004-09-01

To consider the relationship of the parasitic infections including cryptosporidium with chronic diarrhea. Also the effect of chronic disease as pulmonary tuberculosis (TB) and nosocomial infection on the occurrence rate of parasites in cases of chronic diarrhea. Stool samples were collected from 205 patients in teaching, general, child and maternity hospitals in Basrah, Iraq, suffering from chronic diarrhea during 2000. Out of these patients, there were 40 patients with pulmonary TB and 50 inpatients with nosocomial infection. Also 175 apparently healthy individuals who have no episodes of diarrhea for at least 2-months were served as a control group. Direct smear method and then formalin ether sedimentation method were carried out for stool samples to detect intestinal parasites. Fecal smears were prepared from the sediment and stained by the modified Ziehl Neelsen stain for the recovery of red pink oocysts of cryptosporidium. Out of the 205 examined patients, cryptosporidium oocysts were found to be excreted in 20 (9.7%) patients in comparing to 1.1% of the control group. The difference is statistically significant. There were 109 (53.2%) patients found to be positive for intestinal parasitic infections compared to 26 (14.8%) of the control group. The difference is also statistically significant. Out of the 40 TB patients, 2 (5%) were found to excrete cryptosporidium oocysts and also 27 (67.3%) were positive for intestinal parasites. In addition, there were 4 (8%) excreting cryptosporidium oocysts and 23 (46%) infecting by intestinal parasites among the in patients with nosocomial infection. Both acid and non-acid fast parasites should be considered in the differential diagnosis of undiagnosed chronic diarrhea especially among patients with pulmonary TB or nosocomial infection.

Pathological and Ecological Host Consequences of Infection by an Introduced Fish Parasite

PubMed Central

Britton, J. Robert; Pegg, Josephine; Williams, Chris F.

2011-01-01

The infection consequences of the introduced cestode fish parasite Bothriocephalus acheilognathi were studied in a cohort of wild, young-of-the-year common carp Cyprinus carpio that lacked co-evolution with the parasite. Within the cohort, parasite prevalence was 42% and parasite burdens were up to 12% body weight. Pathological changes within the intestinal tract of parasitized carp included distension of the gut wall, epithelial compression and degeneration, pressure necrosis and varied inflammatory changes. These were most pronounced in regions containing the largest proportion of mature proglottids. Although the body lengths of parasitized and non-parasitized fish were not significantly different, parasitized fish were of lower body condition and reduced weight compared to non-parasitized conspecifics. Stable isotope analysis (δ15N and δ13C) revealed trophic impacts associated with infection, particularly for δ15N where values for parasitized fish were significantly reduced as their parasite burden increased. In a controlled aquarium environment where the fish were fed ad libitum on an identical food source, there was no significant difference in values of δ15N and δ13C between parasitized and non-parasitized fish. The growth consequences remained, however, with parasitized fish growing significantly slower than non-parasitized fish, with their feeding rate (items s−1) also significantly lower. Thus, infection by an introduced parasite had multiple pathological, ecological and trophic impacts on a host with no experience of the parasite. PMID:22022606

Host and parasite thermal ecology jointly determine the effect of climate warming on epidemic dynamics.

PubMed

Gehman, Alyssa-Lois M; Hall, Richard J; Byers, James E

2018-01-23

Host-parasite systems have intricately coupled life cycles, but each interactor can respond differently to changes in environmental variables like temperature. Although vital to predicting how parasitism will respond to climate change, thermal responses of both host and parasite in key traits affecting infection dynamics have rarely been quantified. Through temperature-controlled experiments on an ectothermic host-parasite system, we demonstrate an offset in the thermal optima for survival of infected and uninfected hosts and parasite production. We combine experimentally derived thermal performance curves with field data on seasonal host abundance and parasite prevalence to parameterize an epidemiological model and forecast the dynamical responses to plausible future climate-warming scenarios. In warming scenarios within the coastal southeastern United States, the model predicts sharp declines in parasite prevalence, with local parasite extinction occurring with as little as 2 °C warming. The northern portion of the parasite's current range could experience local increases in transmission, but assuming no thermal adaptation of the parasite, we find no evidence that the parasite will expand its range northward under warming. This work exemplifies that some host populations may experience reduced parasitism in a warming world and highlights the need to measure host and parasite thermal performance to predict infection responses to climate change.

Survey of parasites in threatened stocks of coho salmon (Oncorhynchus kisutch) in Oregon by examination of wet tissues and histology.

PubMed

Ferguson, Jayde A; St-Hilaire, Sophie; Peterson, Tracy S; Rodnick, Kenneth J; Kent, Michael L

2011-12-01

We are conducting studies on the impacts of parasites on Oregon coastal coho salmon (Oncorhynchus kistuch). An essential first step is documenting the geographic distribution of infections, which may be accomplished by using different methods for parasite detection. Thus, the objectives of the current study were to (1) identify parasite species infecting these stocks of coho salmon and document their prevalence, density, and geographic distribution; (2) assess the pathology of these infections; and (3) for the first time, determine the sensitivity and specificity of histology for detecting parasites compared with examining wet preparations for muscle and gill infections. We examined 576 fry, parr, and smolt coho salmon in total by histology. The muscle and gills of 219 of these fish also were examined by wet preparation. Fish were collected from 10 different locations in 2006-2007. We identified 21 different species of parasites in these fish. Some parasites, such as Nanophyetus salmincola and Myxobolus insidiosus, were common across all fish life stages from most basins. Other parasites, such as Apophallus sp., were more common in underyearling fish than smolts and had a more restricted geographic distribution. Additional parasites commonly observed were as follows: Sanguinicola sp., Trichodina truttae , Epistylis sp., Capriniana piscium, and unidentified metacercariae in gills; Myxobolus sp. in brain; Myxidium salvelini and Chloromyxum majori in kidney; Pseudocapillaria salvelini and adult digenean spp. in the intestine. Only a few parasites, such as the unidentified gill metacercariae, elicted overt pathologic changes. Histology had generally poor sensitivity for detecting parasites; however, it had relatively good specificity. We recommend using both methods for studies or monitoring programs requiring a comprehensive assessment of parasite identification, enumeration, and parasite-related pathology.

Chronology of parasite-induced alteration of fish behaviour: effects of parasite maturation and host experience.

PubMed

Shirakashi, S; Goater, C P

2005-02-01

We monitored temporal changes in the magnitude of altered host behaviour in minnows (Pimephales promelas) experimentally infected with metacercariae of a brain-encysting trematode (Ornithodiplostomum ptychocheilus). This parasite develops and then encysts in a region of the brain that mediates the optomotor response (OMR), an innate behaviour that links visual stimuli with motor performance. The OMR of infected and uninfected minnows was evaluated between 0 and 10 weeks post-infection (p.i.), an interval spanning the development period of metacercariae to infectivity in birds. Trials involved monitoring the time an individual minnow spent following a spinning drum that had been painted with alternating black and white stripes. At 2 and 4 weeks p.i., infected minnows followed the drum 40% less often than controls. Differences between controls and infected fish declined thereafter, and were undetectable by 10 weeks p.i. Both control and infected fish habituated equally rapidly to the spinning drum. However, the difference in performance between controls and infected fish was 29% for experienced fish and 48% for fish that had never experienced the drum. Because maximum parasite-induced reduction in OMR coincided with the period of maximum parasite development, the behavioural effects are most likely due to unavoidable pathology in the brain associated with developing larvae.

Enforcing host cell polarity: an apicomplexan parasite strategy towards dissemination.

PubMed

Baumgartner, Martin

2011-08-01

The propagation of apicomplexan parasites through transmitting vectors is dependent on effective dissemination of parasites inside the mammalian host. Intracellular Toxoplasma and Theileria parasites face the challenge that their spread inside the host depends in part on the motile capacities of their host cells. In response, these parasites influence the efficiency of dissemination by altering adhesive and/or motile properties of their host cells. Theileria parasites do so by targeting signalling pathways that control host cell actin dynamics. The resulting enforced polar host cell morphology facilitates motility and invasiveness, by establishing focal adhesion and invasion structures at the leading edge of the infected cell. This parasite strategy highlights mechanisms of motility regulation that are also likely relevant for immune or cancer cell motility. Copyright © 2011 Elsevier Ltd. All rights reserved.

Finishing meat goats on birdsfoot trefoil, chicory, or red clover pastures

USDA-ARS?s Scientific Manuscript database

Control of gastrointestinal (GI) parasites in goats is a major challenge for producers. Some forages may contain natural compounds that can help in GI parasite control. This experiment was conducted to evaluate forage production patterns, animal performance, and health when meat goat kids were fin...

75 FR 26647 - Implantation or Injectable Dosage Form New Animal Drugs; Ivermectin

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-12

... solution in cattle and swine for treatment and control of various internal and external parasites. DATES... Veterinary Medicine (HFV-170), Food and Drug Administration, 7500 Standish Pl., Rockville, MD 20855, 240-276... and swine for treatment and control of various internal and external parasites. Sparhawk Laboratories...

Description of the Prometheus Program Alternator/Thruster Integration Laboratory (ATIL)

NASA Technical Reports Server (NTRS)

Baez, Anastacio N.; Birchenough, Arthur G.; Lebron-Velilla, Ramon C.; Gonzalez, Marcelo C.

2005-01-01

The Project Prometheus Alternator Electric Thruster Integration Laboratory's (ATIL) primary two objectives are to obtain test data to influence the power conversion and electric propulsion systems design, and to assist in developing the primary power quality specifications prior to system Preliminary Design Review (PDR). ATIL is being developed in stages or configurations of increasing fidelity and complexity in order to support the various phases of the Prometheus program. ATIL provides a timely insight of the electrical interactions between a representative Permanent Magnet Generator, its associated control schemes, realistic electric system loads, and an operating electric propulsion thruster. The ATIL main elements are an electrically driven 100 kWe Alternator Test Unit (ATU), an alternator controller using parasitic loads, and a thruster Power Processing Unit (PPU) breadboard. This paper describes the ATIL components, its development approach, preliminary integration test results, and current status.

Enhanced Host-Parasite Resistance Based on Down-Regulation of Phelipanche aegyptiaca Target Genes Is Likely by Mobile Small RNA

PubMed Central

Dubey, Neeraj K.; Eizenberg, Hanan; Leibman, Diana; Wolf, Dalia; Edelstein, Menahem; Abu-Nassar, Jackline; Marzouk, Sally; Gal-On, Amit; Aly, Radi

2017-01-01

RNA silencing refers to diverse mechanisms that control gene expression at transcriptional and post-transcriptional levels which can also be used in parasitic pathogens of plants that Broomrapes (Orobanche/Phelipanche spp.) are holoparasitic plants that subsist on the roots of a variety of agricultural crops and cause severe negative effects on the yield and yield quality of those crops. Effective methods for controlling parasitic weeds are scarce, with only a few known cases of genetic resistance. In the current study, we suggest an improved strategy for the control of parasitic weeds based on trans-specific gene-silencing of three parasite genes at once. We used two strategies to express dsRNA containing selected sequences of three Phelipanche aegyptiaca genes PaACS, PaM6PR, and PaPrx1 (pma): transient expression using Tobacco rattle virus (TRV:pma) as a virus-induced gene-silencing vector and stable expression in transgenic tomato Solanum lycopersicum (Mill.) plants harboring a hairpin construct (pBINPLUS35:pma). siRNA-mediated transgene-silencing (20–24 nt) was detected in the host plants. Our results demonstrate that the quantities of PaACS and PaM6PR transcripts from P. aegyptiaca tubercles grown on transgenic tomato or on TRV-infected Nicotiana benthamiana plants were significantly reduced. However, only partial reductions in the quantity of PaPrx1 transcripts were observed in the parasite tubercles grown on tomato and on N. benthamiana plants. Concomitant with the suppression of the target genes, there were significant decreases in the number and weight of the parasite tubercles that grew on the host plants, in both the transient and the stable experimental systems. The results of the work carried out using both strategies point to the movement of mobile exogenous siRNA from the host to the parasite, leading to the impaired expression of essential parasite target genes. PMID:28955363

Effect of Varroa destructor, Wounding and Varroa Homogenate on Gene Expression in Brood and Adult Honey Bees.

PubMed

Koleoglu, Gun; Goodwin, Paul H; Reyes-Quintana, Mariana; Hamiduzzaman, Mollah Md; Guzman-Novoa, Ernesto

2017-01-01

Honey bee (Apis mellifera) gene expression related to immunity for hymenoptaecin (AmHym) and defensin-1 (AmDef-1), longevity for vitellogenin (AmVit2) and stem cell proliferation for poly U binding factor 68 kDa (AmPuf68) was compared following Varroa destructor parasitism, buffer injection and injection of V. destructor compounds in its homogenate. In adults, V. destructor parasitism decreased expression of all four genes, while buffer injection decreased expression of AmHym, AmPuf68 and AmVit2, and homogenate injection decreased expression of AmPuf68 and AmVit2 but increased expression of AmDef-1 relative to their respective controls. The effect of V. destructor parasitism in adults relative to the controls was not significantly different from buffer injection for AmHym and AmVit2 expression, and it was not significantly different from homogenate injection for AmPuf68 and AmVit2. In brood, V. destructor parasitism, buffer injection and homogenate injection decreased AmVit2 expression, whereas AmHym expression was decreased by V. destructor parasitism but increased by buffer and homogenate injection relative to the controls. The effect of varroa parasitism in brood was not significantly different from buffer or homogenate injection for AmPuf68 and AmVit2. Expression levels of the four genes did not correlate with detectable viral levels in either brood or adults. The results of this study indicate that the relative effects of V. destructor parasitism on honey bee gene expression are also shared with other types of stresses. Therefore, some of the effects of V. destructor on honey bees may be mostly due to wounding and injection of foreign compounds into the hemolymph of the bee during parasitism. Although both brood and adults are naturally parasitized by V. destructor, their gene expression responded differently, probably the result of different mechanisms of host responses during development.

Effect of Varroa destructor, Wounding and Varroa Homogenate on Gene Expression in Brood and Adult Honey Bees

PubMed Central

Koleoglu, Gun; Goodwin, Paul H.; Reyes-Quintana, Mariana; Hamiduzzaman, Mollah Md.; Guzman-Novoa, Ernesto

2017-01-01

Honey bee (Apis mellifera) gene expression related to immunity for hymenoptaecin (AmHym) and defensin-1 (AmDef-1), longevity for vitellogenin (AmVit2) and stem cell proliferation for poly U binding factor 68 kDa (AmPuf68) was compared following Varroa destructor parasitism, buffer injection and injection of V. destructor compounds in its homogenate. In adults, V. destructor parasitism decreased expression of all four genes, while buffer injection decreased expression of AmHym, AmPuf68 and AmVit2, and homogenate injection decreased expression of AmPuf68 and AmVit2 but increased expression of AmDef-1 relative to their respective controls. The effect of V. destructor parasitism in adults relative to the controls was not significantly different from buffer injection for AmHym and AmVit2 expression, and it was not significantly different from homogenate injection for AmPuf68 and AmVit2. In brood, V. destructor parasitism, buffer injection and homogenate injection decreased AmVit2 expression, whereas AmHym expression was decreased by V. destructor parasitism but increased by buffer and homogenate injection relative to the controls. The effect of varroa parasitism in brood was not significantly different from buffer or homogenate injection for AmPuf68 and AmVit2. Expression levels of the four genes did not correlate with detectable viral levels in either brood or adults. The results of this study indicate that the relative effects of V. destructor parasitism on honey bee gene expression are also shared with other types of stresses. Therefore, some of the effects of V. destructor on honey bees may be mostly due to wounding and injection of foreign compounds into the hemolymph of the bee during parasitism. Although both brood and adults are naturally parasitized by V. destructor, their gene expression responded differently, probably the result of different mechanisms of host responses during development. PMID:28081188

Reproductive ecology of phorid parasitoids in relation to the head size of leaf-cutting ants Atta sexdens Forel.

PubMed

Farder-Gomes, C F; Oliveira, M A; Gonçalves, P L; Gontijo, L M; Zanuncio, J C; Bragança, M A L; Pires, E M

2017-08-01

The leaf-cutting ant Atta sexdens Forel (Hymenoptera: Formicidae) is one of the most damaging agricultural pests in the Neotropics. Management strategies predominantly rely on the use of general insecticides. What is needed are more species-specific and environmentally friendly options. Parasitioids such as phorid flies (Diptera: Phoridae) may be one such option, but a greater understanding of the ecology of the flies and their ant hosts is essential to devise biological control strategies. Here we report parasitism rates, ant host size, parasitoid abundance per host and resultant sex ratios of two phorid species Apocephalus attophilus Borgmeier and Eibesfeldtphora tonhascai Brown parasitizing A.sexdens. The two species achieved parasitism rates of 1.48 and 1.46%, respectively and the pupal period was 14.7 ± 1.1 days and 22.1 ± 2.8 days, respectively. There was no significant difference between the head capsule width of ants parasitized by either A. attophilus or E. tonhascai. Likewise, there was no significant effect between the head capsule width of parasitized and unparasitized ants for both species. A significant positive correlation was found between the head capsule width of the parasitized ants and the number of adult parasitoids A. attophilus emerged. Ants parasitized by E. tonhascai survived significantly longer than those parasitized by A. attophilus. There was no significant effect of ant head width on the sex ratio of the offspring of either parasitoid species and no significant difference in the sex ratio (male: female) of their offspring. In summary, these data addressed here are important steps when considering natural enemies for biological control. Studying survival of the parasitized ants, parasitoid offspring sex ratio and host size preference allows for a better understanding of ant natural biological control in the field and can help in rearing of A. attophilus and E. tonhascai in laboratory.

Parasite infection and immune and health-state in wild fish exposed to marine pollution.

PubMed

Sueiro, María Cruz; Bagnato, Estefanía; Palacios, María Gabriela

2017-06-15

Association between parasitism and immunity and health-state was investigated in wild Sebastes oculatus after having determined that pollution exposure is associated with altered immune and health-state parameters. Given the importance of the immune system in antiparasite defense we predicted: (i) parasite infection would be higher in pollution-exposed than in control fish and (ii) fish with lower immune and health-state parameters would show higher parasitism than fish in better condition. Metazoan parasite fauna was compared between pollution-exposed and non-exposed fish and parasitic indices were correlated with integrated measures of immunity and health-state. Results provided little support for the predictions; some parasite taxa increased, some decreased, and some were not affected in pollution-exposed fish despite their altered health and immunity. Furthermore, there was no link between individual immune and health-state parameters and parasitism. These findings highlight the complexity of host-parasite-environment interactions in relation to pollution in natural marine ecosystems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Influence of parasitism in controlling the health, reproduction and PAH body burden of petroleum seep mussels

NASA Astrophysics Data System (ADS)

Powell, Eric N.; Barber, Robert D.; Kennicutt, Mahlon C., II; Ford, Susan E.

1999-12-01

Petroleum seep mussels are often exposed to high hydrocarbon concentrations in their natural habitat and, thus, offer the opportunity to examine the relationship between parasitism, disease and contaminant exposure under natural conditions. This is the first report on the histopathology of cold-seep mussels. Seep mussels were collected by submersible from four primary sites in the Gulf of Mexico, lease blocks Green Canyon (GC) 184, GC-234, GC-233, and Garden Banks 425 in 550-650 m water depth. Five types of parasites were identified in section: (1) gill "rosettes" of unknown affinity associated with the gill bacteriocytes, (2) gill "inclusions" similar to chlamydia/rickettsia inclusions, (3) extracellular gill ciliates, (4) body "inclusions" that also resemble chlamydial/rickettsial inclusions, and (5) Bucephalus-like trematodes. Comparison to shallow-water mytilids demonstrates that: (1) both have similar parasite faunas; (2) seep mytilids are relatively heavily parasitized; and (3) infection intensities are extremely high in comparison to shallow-water mytilids for Bucephalus and chlamydia/rickettsia. In this study, the lowest prevalence for chlamydia/rickettsia was 67%. Prevalences of 100% were recorded from three populations. Bucephalus prevalence was ⩾70% in three of 10 populations. The parasite fauna was highly variable between populations. Some important parasites were not observed in some primary sites. Even within primary sites, some important parasites were not observed in some populations. Bucephalus may exert a significant influence on seep mussel population dynamics. Forty percent of the populations in this study are severely reproductively compromised by Bucephalus infection. Only a fraction of petroleum seep mussel populations are maintaining the entire beta-level population structure of this species. Variation in two parasites, gill ciliates and Bucephalus, explained most of the variation in PAH body burden between mussel populations. PAHs are known to be sequestered preferentially in gametic tissue. Bucephalus would be expected to reduce overall body burden, at high infection intensities, by replacing gametic tissue. PAH concentrations exceeded 1 ppm in 4 of 9 populations, a ratio significantly higher than the 8 of 30 mussel locales in the NOAA Mussel Watch Program. Only five Mussel Watch locales exceeded the highest value for a petroleum seep population. Digestive gland and gill tissue atrophy were not significantly correlated with PAH body burden, even though some populations were characterized by body burdens exceeding 1 ppm, suggesting that seep mussels may not be as sensitive to PAH exposure as are some shallow-water mytilid populations.

Impact of introduction of Bactrocera dorsalis (Diptera: Tephritidae) and classical biological control releases of Fopius arisanus (Hymenoptera: Braconidae) on economically important fruit flies in French Polynesia.

PubMed

Vargas, Roger I; Leblanc, Luc; Putoa, Rudolph; Eitam, Avi

2007-06-01

Oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), was discovered on Tahiti Island in July 1996. Eradication programs were conducted from 1997 to 2001, but failed. From 1998 to 2006, B. dorsalis was recovered from 29 different host fruit from the five Society Islands: Tahiti, Moorea, Raiatea, Tahaa, and Huahine. Analysis of coinfestation patterns by B. dorsalis, Bactrocera tryoni (Froggatt), and Bactrocera kirki (Froggatt) suggested B. dorsalis had displaced these two species and become the most abundant fruit fly in coastal areas. To suppress B. dorsalis populations, a classical biological control program was initiated to introduce the natural enemy Fopius arisanus (Sonan) (Hymenoptera: Braconidae) into French Polynesia from Hawaii. Wasps were released and established on Tahiti, Moorea, Raiatea, Tahaa, and Huahine Islands. In guava, Psidium guajava L., collections for Tahiti, F. arisanus parasitism of fruit flies was 2.1, 31.8, 37.5, and 51.9% for fruit collected for 2003, 2004, 2005 and 2006, respectively. Based on guava collections in 2002 (before releases) and 2006 (after releases), there was a subsequent decrease in numbers of B. dorsalis, B. tryoni, and B. kirki fruit flies emerging (per kilogram of fruit) by 75.6, 79.3, and 97.9%, respectively. These increases in F. arisanus parasitism and decreases in infestation were similar for other host fruit. Establishment of F. arisanus is the most successful example of classical biological control of fruit flies in the Pacific area outside of Hawaii and serves as a model for introduction into South America, Africa, and China where species of the B. dorsalis complex are established.

Parasite species of the endangered Iberian wolf (Canis lupus signatus) and a sympatric widespread carnivore.

PubMed

Figueiredo, Ana; Oliveira, Lucia; Madeira de Carvalho, Luís; Fonseca, Carlos; Torres, Rita Tinoco

2016-08-01

Parasites have a profound impact on wildlife population dynamics. However, until some years ago, studies on the occurrence and prevalence of wildlife parasites were neglected comparatively with the studies on humans and domestic animals. In this study, we determined the parasite prevalence of two sympatric wild canids: the endangered Iberian wolf (Canis lupus signatus) and the widespread red fox (Vulpes vulpes), in central Portugal. From November 2014 to July 2015, fresh fecal samples from both species were collected monthly in several transects distributed throughout the study area. All samples were submitted to several coprological techniques. In total, 6 helminth parasites (Crenosoma vulpis, Angiostrongylus vasorum, Toxocara canis, Trichuris vulpis, Ancylostomatidae, Toxascaris leonina), and a protozoa (Balantidium coli) were identified based on size and morphology. The red fox was infected by seven different parasites while the Iberian wolf was infected by four. All parasites present in wolf were also present in the red fox. C. vulpis had the higher prevalence in red fox, while Ancylostomatidae were the most prevalent parasites in wolf. To our knowledge, this is the first study in this isolated subpopulation of the Iberian wolf. Our results show that both carnivores carry parasites that are of concern as they are pathogenic to humans and other wild and domestic animals. We suggest that surveillance programs must also include monitoring protocols of wildlife; particularly endangered species.

Selective predation and productivity jointly drive complex behavior in host-parasite systems.

PubMed

Hall, Spencer R; Duffy, Meghan A; Cáceres, Carla E

2005-01-01

Successful invasion of a parasite into a host population and resulting host-parasite dynamics can depend crucially on other members of a host's community such as predators. We do not fully understand how predation intensity and selectivity shape host-parasite dynamics because the interplay between predator density, predator foraging behavior, and ecosystem productivity remains incompletely explored. By modifying a standard susceptible-infected model, we show how productivity can modulate complex behavior induced by saturating and selective foraging behavior of predators in an otherwise stable host-parasite system. When predators strongly prefer parasitized hosts, the host-parasite system can oscillate, but predators can also create alternative stable states, Allee effects, and catastrophic extinction of parasites. In the latter three cases, parasites have difficulty invading and/or persisting in ecosystems. When predators are intermediately selective, these more complex behaviors become less important, but the host-parasite system can switch from stable to oscillating and then back to stable states along a gradient of predator control. Surprisingly, at higher productivity, predators that neutrally select or avoid parasitized hosts can catalyze extinction of both hosts and parasites. Thus, synergy between two enemies can end disastrously for the host. Such diverse outcomes underscore the crucial importance of the community and ecosystem context in which host-parasite interactions occur.

RNA interference as a resistance mechanism against crop parasites in Africa: a 'Trojan horse' approach.

PubMed

Runo, Steven; Alakonya, Amos; Machuka, Jesse; Sinha, Neelima

2011-02-01

Biological crop pests cause serious economic losses. In Africa, the most prevalent parasites are insect pests, plant pathogenic root-knot nematodes, viruses and parasitic plants. African smallholder farmers struggle to overcome these parasitic constraints to agricultural production. Crop losses and the host range of these parasites have continued to increase in spite of the use of widely advocated control methods. A sustainable method to overcome biological pests in Africa would be to develop crop germplasm resistant to parasites. This is achievable using either genetic modification (GM) or a non-GM approach. However, there is a paucity of resistant genes available for introduction. Additionally, the biological processes underpinning host parasite resistance are not sufficiently well understood. The authors review a technology platform for using RNA-mediated interference (RNAi) as bioengineered resistance to important crop parasites in Africa. To achieve acquired resistance, a host crop is stably transformed with a transgene that encodes a hairpin RNA targeting essential parasitic genes. The RNAi sequence is chosen in such a way that it shares no homology with the host's genes, so it remains 'inactive' until parasitism. Upon parasitism, the RNAi sequence enters the parasite and post-transcriptional gene silencing (PTGS) mechanisms are activated, leading to the death of the parasite. Copyright © 2010 Society of Chemical Industry.

Multidrug resistance in parasites: ABC transporters, P-glycoproteins and molecular modelling.

PubMed

Jones, P M; George, A M

2005-04-30

Parasitic diseases, caused by protozoa, helminths and arthropods, rank among the most important problems in human and veterinary medicine, and in agriculture, leading to debilitating sicknesses and loss of life. In the absence of vaccines and with the general failure of vector eradication programs, drugs are the main line of defence, but the newest drugs are being tracked by the emergence of resistance in parasites, sharing ominous parallels with multidrug resistance in bacterial pathogens. Any of a number of mechanisms will elicit a drug resistance phenotype in parasites, including: active efflux, reduced uptake, target modification, drug modification, drug sequestration, by-pass shunting, or substrate competition. The role of ABC transporters in parasitic multidrug resistance mechanisms is being subjected to more scrutiny, due in part to the established roles of certain ABC transporters in human diseases, and also to an increasing portfolio of ABC transporters from parasite genome sequencing projects. For example, over 100 ABC transporters have been identified in the Escherichia coli genome, but to date only about 65 in all parasitic genomes. Long established laboratory investigations are now being assisted by molecular biology, bioinformatics, and computational modelling, and it is in these areas that the role of ABC transporters in parasitic multidrug resistance mechanisms may be defined and put in perspective with that of other proteins. We discuss ABC transporters in parasites, and conclude with an example of molecular modelling that identifies a new interaction between the structural domains of a parasite P-glycoprotein.

Epidemiological assessment of neglected diseases in children: lymphatic filariasis and soil-transmitted helminthiasis.

PubMed

Aguiar-Santos, Ana M; Medeiros, Zulma; Bonfim, Cristine; Rocha, Abraham C; Brandão, Eduardo; Miranda, Tereza; Oliveira, Paula; Sarinho, Emanuel S C

2013-01-01

To report the prevalence of lymphatic filariasis and intestinal parasitic infections in school-aged children living in a filariasis endemic area and discuss about the therapeutic regimen adopted in Brazil for the large-scale treatment of filariasis. A cross-sectional study including 508 students aged 5-18 years old, enrolled in public schools within the city of Olinda, Pernambuco. The presence of intestinal parasites was analyzed using the Hoffman, Pons and Janer method on 3 stool samples. The diagnosis of filarial infection was performed using the rapid immunochromatographic technique (ICT) for the antigen, and the polycarbonate membrane filtration for the presence of microfilariae. Descriptive statistics of the data was performed using EpiInfo version 7. The prevalence of filariasis was 13.8% by ICT and 1.2% by microfilaraemia, while intestinal parasites were detected in 64.2% of cases. Concurrent diagnosis of filariasis and intestinal parasites was 9.4%, while 31.5% of students were parasite-free. Among individuals with intestinal parasites, 55% had one parasite and 45% had more than one parasite. Geohelminths occurred in 72.5% of the parasited individuals. In the group with filarial infection the prevalence of soil-transmitted helminthiasis was 54.5%. The simultaneous diagnosis of filariasis and intestinal parasites as well as the high frequency of geohelminths justify the need to reevaluate the treatment strategy used in the Brazilian filariasis large-scale treatment program. Copyright © 2013 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

Parasites and genetic diversity in an invasive bumblebee.

PubMed

Jones, Catherine M; Brown, Mark J F

2014-11-01

Biological invasions are facilitated by the global transportation of species and climate change. Given that invasions may cause ecological and economic damage and pose a major threat to biodiversity, understanding the mechanisms behind invasion success is essential. Both the release of non-native populations from natural enemies, such as parasites, and the genetic diversity of these populations may play key roles in their invasion success. We investigated the roles of parasite communities, through enemy release and parasite acquisition, and genetic diversity in the invasion success of the non-native bumblebee, Bombus hypnorum, in the United Kingdom. The invasive B. hypnorum had higher parasite prevalence than most, or all native congeners for two high-impact parasites, probably due to higher susceptibility and parasite acquisition. Consequently parasites had a higher impact on B. hypnorum queens' survival and colony-founding success than on native species. Bombus hypnorum also had lower functional genetic diversity at the sex-determining locus than native species. Higher parasite prevalence and lower genetic diversity have not prevented the rapid invasion of the United Kingdom by B. hypnorum. These data may inform our understanding of similar invasions by commercial bumblebees around the world. This study suggests that concerns about parasite impacts on the small founding populations common to re-introduction and translocation programs may be less important than currently believed. © 2014 The Authors. Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.

Hexamermis popilliae n. sp. (Nematoda: Mermithidae) parasitizing the Japanese beetle Popillia japonica Newman (Coleoptera: Scarabaeidae) in Italy.

PubMed

Mazza, Giuseppe; Paoli, Francesco; Strangi, Agostino; Torrini, Giulia; Marianelli, Leonardo; Peverieri, Giuseppino Sabbatini; Binazzi, Francesco; Bosio, Giovanni; Sacchi, Stefano; Benvenuti, Claudia; Venanzio, Davide; Giacometto, Emanuela; Roversi, Pio F; Poinar, George O

2017-10-01

A new species of mermithid nematode, Hexamermis popilliae n. sp. (Nematoda: Mermithidae) is described from the Japanese beetle Popillia japonica Newman in Italy, an area of new introduction for this invasive pest. The combination of the following characters separates H. popilliae from other members of the genus Hexamermis Steiner, 1924: adult head obtuse; amphidial pouches slightly posterior to lateral head papillae in female but adjacent to lateral head papillae in males; amphidial openings large, well developed; amphidial pouches elliptical in females and oblong in males; cuticular vulvar cone well developed, vulvar lips greatly reduced or lacking, vagina curved at tip where meeting uteri, without reverse bend (not S-shaped), spicules slightly curved, with a slight bend in the basal portion, approximately equal to body width at cloaca. This is the first record of a species of Hexamermis parasitizing the Japanese beetle Popillia japonica. The only previous mention of mermithid nematodes from P. japonica was an undescribed species of Psammomermis in North America. Hexamermis popilliae will be evaluated as a potential biological control agent in an integrated control program of the Japanese beetle in Italy.

Management Options for Control of a Stunt and Needle Nematode in Southern Forest Nurseries

Treesearch

Michelle M. Cram; Stephen W. Fraedrich

2005-01-01

Crop rotation and fallow are management options that can be used to control plant parasitic nematodes in forest tree nurseries. Before these options can be put into practice, it is important to determine the host range and survivability under fallow of the parasitic nematode to be controlled. The results of host range tests on a needle nematode (Longidorus...

The conserved apicomplexan Aurora kinase TgArk3 is involved in endodyogeny, duplication rate and parasite virulence

PubMed Central

Morlon-Guyot, Juliette; Bordat, Yann; Lebrun, Maryse; Gubbels, Marc-Jan; Doerig, Christian; Daher, Wassim

2016-01-01

Aurora kinases are eukaryotic serine/threonine protein kinases that regulate key events associated with chromatin condensation, centrosome and spindle function, and cytokinesis. Elucidating the roles of Aurora kinases in apicomplexan parasites is crucial to understand the cell cycle control during Plasmodium schizogony or Toxoplasma endodyogeny. Here, we report on the localization of two previously uncharacterized Toxoplasma Aurora-related kinases (Ark2 and Ark3) in tachyzoites and of the uncharacterized Ark3 orthologue in Plasmodium falciparum erythrocytic stages. In T. gondii, we show that TgArk2 and TgArk3 concentrate at specific sub-cellular structures linked to parasite division: the mitotic spindle and intranuclear mitotic structures (TgArk2), and the outer core of the centrosome and the budding daughter cells cytoskeleton (TgArk3). By tagging the endogenous PfArk3 gene with the green fluorescent protein (GFP) in live parasites, we show that PfArk3 protein expression peaks late in schizogony and localizes at the periphery of budding schizonts. Disruption of the TgArk2 gene reveals no essential function for tachyzoite propagation in vitro, which is surprising giving that the P. falciparum and P. berghei orthologues are essential for erythrocyte schizogony. In contrast, knock-down of TgArk3 protein results in pronounced defects in parasite division and a major growth deficiency. TgArk3-depleted parasites display several defects, such as reduced parasite growth rate, delayed egress and parasite duplication, defect in rosette formation, reduced parasite size and invasion efficiency and lack of virulence in mice. Our study provides new insights into cell cycle control in Toxoplasma and malaria parasites, and highlights Aurora kinase 3 as potential drug target. PMID:26833682

A Bovine Lymphosarcoma Cell Line Infected with Theileria annulata Exhibits an Irreversible Reconfiguration of Host Cell Gene Expression

PubMed Central

Durrani, Zeeshan; Pillai, Sreerekha S.; Baird, Margaret; Shiels, Brian R.

2013-01-01

Theileria annulata, an intracellular parasite of bovine lymphoid cells, induces substantial phenotypic alterations to its host cell including continuous proliferation, cytoskeletal changes and resistance to apoptosis. While parasite induced modulation of host cell signal transduction pathways and NFκB activation are established, there remains considerable speculation on the complexities of the parasite directed control mechanisms that govern these radical changes to the host cell. Our objectives in this study were to provide a comprehensive analysis of the global changes to host cell gene expression with emphasis on those that result from direct intervention by the parasite. By using comparative microarray analysis of an uninfected bovine cell line and its Theileria infected counterpart, in conjunction with use of the specific parasitacidal agent, buparvaquone, we have identified a large number of host cell gene expression changes that result from parasite infection. Our results indicate that the viable parasite can irreversibly modify the transformed phenotype of a bovine cell line. Fifty percent of genes with altered expression failed to show a reversible response to parasite death, a possible contributing factor to initiation of host cell apoptosis. The genes that did show an early predicted response to loss of parasite viability highlighted a sub-group of genes that are likely to be under direct control by parasite infection. Network and pathway analysis demonstrated that this sub-group is significantly enriched for genes involved in regulation of chromatin modification and gene expression. The results provide evidence that the Theileria parasite has the regulatory capacity to generate widespread change to host cell gene expression in a complex and largely irreversible manner. PMID:23840536

Are We on Our Way to Achieving the 2020 Goals for Schistosomiasis Morbidity Control Using Current World Health Organization Guidelines?

PubMed

Toor, Jaspreet; Alsallaq, Ramzi; Truscott, James E; Turner, Hugo C; Werkman, Marleen; Gurarie, David; King, Charles H; Anderson, Roy M

2018-06-01

Schistosomiasis remains an endemic parasitic disease affecting millions of people around the world. The World Health Organization (WHO) has set goals of controlling morbidity to be reached by 2020, along with elimination as a public health problem in certain regions by 2025. Mathematical models of parasite transmission and treatment impact have been developed to assist in controlling the morbidity caused by schistosomiasis. These models can inform and guide implementation policy for mass drug administration programs, and help design monitoring and evaluation activities. We use these models to predict whether the guidelines set by the WHO are on track for achieving their 2020 goal for the control of morbidity, specifically for Schistosoma mansoni. We examine whether programmatic adaptations; namely increases in treatment coverage and/or expansion to adult inclusion in treatment, will improve the likelihood of reaching the WHO goals. We find that in low-prevalence settings, the goals are likely to be attainable under current WHO guidelines, but in moderate to high-prevalence settings, the goals are less likely to be achieved unless treatment coverage is increased and expanded to at least 85% for school-aged children and 40% for adults. To improve the likelihood of reaching the WHO goals, programmatic adaptations are required, particularly for moderate- to high-prevalence settings. Furthermore, improvements in adherence to treatment, potential development of candidate vaccines, and enhanced snail control and WASH (water, sanitation, and hygiene) measures will all assist in achieving the goals.

Evaluation of Clonostachys rosea for Control of Plant-Parasitic Nematodes in Soil and in Roots of Carrot and Wheat.

PubMed

Iqbal, Mudassir; Dubey, Mukesh; McEwan, Kerstin; Menzel, Uwe; Franko, Mikael Andersson; Viketoft, Maria; Jensen, Dan Funck; Karlsson, Magnus

2018-01-01

Biological control is a promising approach to reduce plant diseases caused by nematodes. We tested the effect of the fungus Clonostachys rosea strain IK726 inoculation on nematode community composition in a naturally nematode infested soil in a pot experiment, and the effect of C. rosea on plant health. The numbers of plant-parasitic nematode genera extracted from soil and plant roots decreased by 40 to 73% when C. rosea was applied, while genera of nonparasitic nematodes were not affected. Soil inoculation of C. rosea increased fresh shoot weight and shoot length of wheat plants by 20 and 24%, respectively, while only shoot dry weight increased by 48% in carrots. Light microscopy of in vitro C. rosea-nematode interactions did not reveal evidence of direct parasitism. However, culture filtrates of C. rosea growing in potato dextrose broth, malt extract broth and synthetic nutrient broth exhibited toxicity toward nematodes and immobilized 57, 62, and 100% of the nematodes, respectively, within 48 h. This study demonstrates that C. rosea can control plant-parasitic nematodes and thereby improve plant growth. The most likely mechanism responsible for the antagonism is antibiosis through production of nematicidal compounds, rather than direct parasitism.

Parasitic load control system for exhaust temperature control

DOEpatents

Strauser, Aaron D.; Coleman, Gerald N.; Coldren, Dana R.

2009-04-28

A parasitic load control system is provided. The system may include an exhaust producing engine and a fuel pumping mechanism configured to pressurize fuel in a pressure chamber. The system may also include an injection valve configured to cause fuel pressure to build within the pressure chamber when in a first position and allow injection of fuel from the pressure chamber into one or more combustion chambers of the engine when in a second position. The system may further include a controller configured to independently regulate the pressure in the pressure chamber and the injection of fuel into the one or more combustion chambers, to increase a load on the fuel pumping mechanism, increasing parasitic load on the engine, thereby increasing a temperature of the exhaust produced by the engine.

Natural genetic and induced plant resistance, as a control strategy to plant-parasitic nematodes alternative to pesticides.

PubMed

Molinari, Sergio

2011-03-01

Plant-parasitic nematodes are pests of a wide range of economically important crops, causing severe losses to agriculture. Natural genetic resistance of plants is expected to be a valid solution of the many problems nematodes cause all over the world. Progress in resistance applications is particularly important for the less-developed countries of tropical and subtropical regions, since use of resistant cultivars may be the only possible and economically feasible control strategy in those farming systems. Resistance is being considered of particular importance also in modern high-input production systems of developed countries, as the customary reliance on chemical nematicides has been restricted or has come to an end. This review briefly describes the genetic bases of resistance to nematodes in plants and focuses on the chances and problems of its exploitation as a key element in an integrated management program. Much space is dedicated to the major problem of resistance durability, in that the intensive use of resistant cultivars is likely to increasingly induce the selection of virulent populations able to "break" the resistance. Protocols of pest-host suitability are described, as bioassays are being used to evaluate local nematode populations in their potential to be selected on resistant germplasm and endanger resistant crops. The recent progress in using robust and durable resistances against nematodes as an efficient method for growers in vegetable cropping systems is reported, as well as the possible use of chemicals that do not show any unfavorable impact on environment, to induce in plants resistance against plant-parasitic nematodes.

Effects of plant tannin extracts supplementation on animal performance and gastrointestinal parasites infestation in steers grazing winter wheat

USDA-ARS?s Scientific Manuscript database

Twenty-six stocker cattle (286.1 ± 25.7 kg) were used to quantify the effect of commercial plant tannin extracts (control vs. mimosa and chestnut tannins) on animal performance, gastrointestinal parasites control, and plasma metabolite changes in heifers grazing winter wheat forage (Triticum aestivu...

Efficacy of several soil amendments for the control of Xiphinema index and Meloidogyne javanica on grapevine seedlings in Pakistan

USDA-ARS?s Scientific Manuscript database

This study was done to investigate the effect of several organic amendments for the control of plant-parasitic nematodes. The effects of four soil amendments applied individually or in several combinations and a chemical nematicide (carbofuran) on plant-parasitic nematodes associated with the rhizos...

Detecting genotypic variation among the single spore isolates of Pasteuria penetrans population occuring in Florida using SNP-based markers

USDA-ARS?s Scientific Manuscript database

Pasteuria penetrans is a naturally occurring soil-borne endospore-forming bacterium, which functions as a castrating parasite of plant-parasitic nematodes belonging to the genus Meloidogyne. Pasteuria penetrans is established as an effective biological control agent for control and management o...

Behavioural aspects of the control of parasitic diseases*

PubMed Central

Dunn, Frederick L.

1979-01-01

Human behaviour has been largely neglected in research on the parasitic diseases, in part because of the long-standing separation of the behavioural disciplines from the physical and biomedical sciences. Some of the reasons for the persistence of this ”intellectual discontinuity” are discussed. The paper is principally concerned with the prospects for greater use of the methods and orientations of the behavioural sciences in parasitic disease research and control programmes. Behavioural research tends to fall into two categories employing, on the one hand, survey research and epidemiological methods and, on the other, participant observation and interviewing in depth. These approaches are shown to be complementary—equally useful and necessary. Various categories of health-related behaviour and kinds of research objective are reviewed in the following sections. Special attention is given to psychosocial cost—benefit studies, to analyses of control sectors, and to the formulation of a control philosophy. Finally, some specific behavioural research needs are discussed for some of the parasitic diseases of priority in the UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases—schistosomiasis, filariasis, American and African trypanosomiases, and malaria. PMID:316733

One world health: socioeconomic burden and parasitic disease control priorities.

PubMed

Torgerson, Paul R

2013-08-01

Parasitic diseases present a considerable socio-economic impact to society. Zoonotic parasites can result in a considerable burden of disease in people and substantive economic losses to livestock populations. Ameliorating the effects of these diseases may consist of attempts at eradicating specific diseases at a global level, eliminating them at a national or local level or controlling them to minimise incidence. Alternatively with some parasitic zoonoses it may only be possible to treat human and animal cases as they arise. The choice of approach will be determined by the potential effectiveness of a disease control programme, its cost and the cost effectiveness or cost benefit of undertaking the intervention. Furthermore human disease burden is being increasingly measured by egalitarian non-financial measures which are difficult to apply to livestock. This adds additional challenges to the assessment of socio-economic burdens of zoonotic diseases. Using examples from the group of neglected zoonotic diseases, information regarding the socio-economic effects is reviewed together with how this information is used in decision making with regard to disease control and treatment. Copyright © 2013 Elsevier B.V. All rights reserved.

Parasitic resistive switching uncovered from complementary resistive switching in single active-layer oxide memory device

NASA Astrophysics Data System (ADS)

Zhu, Lisha; Hu, Wei; Gao, Chao; Guo, Yongcai

2017-12-01

This paper reports the reversible transition processes between the bipolar and complementary resistive switching (CRS) characteristics on the binary metal-oxide resistive memory devices of Pt/HfO x /TiN and Pt/TaO x /TiN by applying the appropriate bias voltages. More interestingly, by controlling the amplitude of the negative bias, the parasitic resistive switching effect exhibiting repeatable switching behavior is uncovered from the CRS behavior. The electrical observation of the parasitic resistive switching effect can be explained by the controlled size of the conductive filament. This work confirms the transformation and interrelationship among the bipolar, parasitic, and CRS effects, and thus provides new insight into the understanding of the physical mechanism of the binary metal-oxide resistive switching memory devices.

Evaluation of Copper Supplementation to Control Haemonchus contortus Infections of Sheep in Sweden

PubMed Central

Waller, PJ; Bernes, G; Rudby-Martin, L; Ljungström, B-L; Rydzik, A

2004-01-01

A pen study was conducted to assess the effect of providing daily copper mineral supplement, or copper wire particle (COWP) capsules, on established or incoming mixed nematode infections in young sheep. For lambs with established (6 week old) infections, COWP resulted in 97% and 56% reduction of the adult and early L4 stages of H. contortus, respectively, compared with controls (p < 0.001). Additionally there was a 74% reduction in Teladorsagia circumcincta infections in the COWP lambs compared with controls (p < 0.01). However, no effect was observed when COWP were given at the commencement of a larval dosing period of 6 weeks. There was no significant effect of copper mineral supplement (given at the recommended rate to prevent Cu deficiency) on either established, or developing parasite infections. In addition, a field trial was conducted on a commercial farm to assess the effects of COWP in the management of recurrent H. contortus infections, but lack of parasites during the grazing season prevented an adequate assessment from being made. These results indicate that there is little, if any, benefit from a parasite control standpoint in recommending copper therapy, specifically to control parasites in Swedish sheep flocks. PMID:15663075

Translational Control in Plasmodium and Toxoplasma Parasites

PubMed Central

Joyce, Bradley R.; Sullivan, William J.; Nussenzweig, Victor

2013-01-01

The life cycles of apicomplexan parasites such as Plasmodium spp. and Toxoplasma gondii are complex, consisting of proliferative and latent stages within multiple hosts. Dramatic transformations take place during the cycles, and they demand precise control of gene expression at all levels, including translation. This review focuses on the mechanisms that regulate translational control in Plasmodium and Toxoplasma, with a particular emphasis on the phosphorylation of the α subunit of eukaryotic translation initiation factor 2 (eIF2α). Phosphorylation of eIF2α (eIF2α∼P) is a conserved mechanism that eukaryotic cells use to repress global protein synthesis while enhancing gene-specific translation of a subset of mRNAs. Elevated levels of eIF2α∼P have been observed during latent stages in both Toxoplasma and Plasmodium, indicating that translational control plays a role in maintaining dormancy. Parasite-specific eIF2α kinases and phosphatases are also required for proper developmental transitions and adaptation to cellular stresses encountered during the life cycle. Identification of small-molecule inhibitors of apicomplexan eIF2α kinases may selectively interfere with parasite translational control and lead to the development of new therapies to treat malaria and toxoplasmosis. PMID:23243065

Translational control in Plasmodium and toxoplasma parasites.

PubMed

Zhang, Min; Joyce, Bradley R; Sullivan, William J; Nussenzweig, Victor

2013-02-01

The life cycles of apicomplexan parasites such as Plasmodium spp. and Toxoplasma gondii are complex, consisting of proliferative and latent stages within multiple hosts. Dramatic transformations take place during the cycles, and they demand precise control of gene expression at all levels, including translation. This review focuses on the mechanisms that regulate translational control in Plasmodium and Toxoplasma, with a particular emphasis on the phosphorylation of the α subunit of eukaryotic translation initiation factor 2 (eIF2α). Phosphorylation of eIF2α (eIF2α∼P) is a conserved mechanism that eukaryotic cells use to repress global protein synthesis while enhancing gene-specific translation of a subset of mRNAs. Elevated levels of eIF2α∼P have been observed during latent stages in both Toxoplasma and Plasmodium, indicating that translational control plays a role in maintaining dormancy. Parasite-specific eIF2α kinases and phosphatases are also required for proper developmental transitions and adaptation to cellular stresses encountered during the life cycle. Identification of small-molecule inhibitors of apicomplexan eIF2α kinases may selectively interfere with parasite translational control and lead to the development of new therapies to treat malaria and toxoplasmosis.

Preharvest food safety.

PubMed

Childers, A B; Walsh, B

1996-07-23

Preharvest food safety is essential for the protection of our food supply. The production and transport of livestock and poultry play an integral part in the safety of these food products. The goals of this safety assurance include freedom from pathogenic microorganisms, disease, and parasites, and from potentially harmful residues and physical hazards. Its functions should be based on hazard analysis and critical control points from producer to slaughter plant with emphasis on prevention of identifiable hazards rather than on removal of contaminated products. The production goal is to minimize infection and insure freedom from potentially harmful residues and physical hazards. The marketing goal is control of exposure to pathogens and stress. Both groups should have functional hazard analysis and critical control points management programs which include personnel training and certification of producers. These programs must cover production procedures, chemical usage, feeding, treatment practices, drug usage, assembly and transportation, and animal identification. Plans must use risk assessment principles, and the procedures must be defined. Other elements would include preslaughter certification, environmental protection, control of chemical hazards, live-animal drug-testing procedures, and identification of physical hazards.

Targeting ticks for control of selected hemoparasitic diseases of cattle.

PubMed

Kocan, K M

1995-03-01

Development in and transmission of hemoparasites by tick vectors are phenomena closely synchronized with the tick feeding cycle. In all known life cycles, initial infection of tick tissues occurs in midgut epithelial cells and transmission is effected as ticks feed after parasites have developed and multiplied in salivary glands. Many factors reviewed affect development and transmission of hemoparasites by ticks including age of ticks, artificial temperature, climate and/or season, tick stage or sex, hemoparasite variation, concurrent infection of ticks with other pathogens, host cell susceptibility, transovarial transmission, effect of hemoparasites on tick biology, and the effect of infecting parasitemia level in cattle on infection rates in ticks. Four hemoparasites of cattle, Anaplasma marginale, Cowdria ruminantium, Theileria parva, and Babesia spp., are all dependent on ticks for biological transmission. Babesia is transmitted transovarially whereas the other three are transmitted transstadially. Mechanical transfer of infective blood via fomites and mouthparts of biting arthropods is also a major means of transmission for Anaplasma marginale but not of the others. Potential control methods for hemoparasites that target parasites as they are developing in their respective tick hosts include tick control, vaccines (against ticks and parasites), and drugs (against ticks and parasites). Successful application of control strategies will be dependent upon thorough understanding of parasite developmental cycles, biology of the tick vectors and the immune response of cattle to ticks and to hemoparasites. The most effective control measures will be those that are targeted against both ticks and the hemoparasites they vector.

Ethnoveterinary plants and practices used for ecto-parasite control in semi-arid smallholder farming areas of Zimbabwe.

PubMed

Nyahangare, Emmanuel Tendai; Mvumi, Brighton Marimanzi; Mutibvu, Tonderai

2015-04-30

The inclusion of traditional plant-based ecto-parasite control methods in primary health care of livestock is increasingly becoming an important intervention for improving livestock productivity in resource-challenged smallholder farming areas. In this study, commonly used plants used for the control of cattle ticks and other pests were identified through a survey in four semi-arid districts of Zimbabwe. A standard structured questionnaire with details of demographics, socioeconomic status of households, livestock parasites, control practices and list of ethnoveterinary plants used was used to interview 233 knowledgeable smallholder farmers in four districts. Focus group discussions with community members further provided insights on how the plants were being used and other issues surrounding ecto-parasite control and indigenous knowledge systems in the study areas. The older generation (>40 years) of the respondents were knowledgeable about ethnoveterinary plants and practices. Overall, 51 plant species were reportedly effective against cattle ticks and other livestock parasites. The most frequently mentioned plants were in descending order, Cissus quadrangularis (30.1%), Lippia javanica (19.6%), Psydrax livida (14.9%) and Aloe sp (14.9%). Most of the plant materials were prepared by crushing and soaking in water and spraying the extract on animals. Despite the knowledge of these useful pesticidal plants, the preferred animal health care for cattle and other highly ranked livestock species is still the use of commercial acaricides. Cattle dipping services were reported sporadic by 48% of the respondents. Traditional knowledge and plants are considered only as an alternative in the absence of conventional synthetic products. Livestock farming communities know of plant species used for livestock ecto-parasite control. The plant species are mostly used to complement commercial products. More work, is required to confirm the acaricidal properties claimed by the farmers in order to optimize and promote sustainable use of these plants.

The past, present, and future of Leishmania genomics and transcriptomics

PubMed Central

Cantacessi, Cinzia; Dantas-Torres, Filipe; Nolan, Matthew J.; Otranto, Domenico

2015-01-01

It has been nearly 10 years since the completion of the first entire genome sequence of a Leishmania parasite. Genomic and transcriptomic analyses have advanced our understanding of the biology of Leishmania, and shed new light on the complex interactions occurring within the parasite–host–vector triangle. Here, we review these advances and examine potential avenues for translation of these discoveries into treatment and control programs. In addition, we argue for a strong need to explore how disease in dogs relates to that in humans, and how an improved understanding in line with the ‘One Health’ concept may open new avenues for the control of these devastating diseases. PMID:25638444

Malaria Evolution in South Asia: Knowledge for Control and Elimination

PubMed Central

Narayanasamy, Krishnamoorthy; Chery, Laura; Basu, Analabha; Duraisingh, Manoj T.; Escalante, Ananias; Fowble, Joseph; Guler, Jennifer L.; Herricks, Thurston; Kumar, Ashwani; Majumder, Partha; Maki, Jennifer; Mascarenhas, Anjali; Rodrigues, Janneth; Roy, Bikram; Sen, Somdutta; Shastri, Jayanthi; Smith, Joseph; Valecha, Neena; White, John; Rathod, Pradipsinh K.

2013-01-01

The study of malaria parasites on the Indian subcontinent should help us understand unexpected disease outbreaks and unpredictable disease presentations from Plasmodium falciparum and from Plasmodium vivax infections. The Malaria Evolution in South Asia (MESA) research program is one of ten International Centers of Excellence for Malaria Research (ICEMR) sponsored by the US National Institute of Health. In this second of two reviews, we describe why population structures of Plasmodia in India will be characterized and how we will determine their consequences on disease presentation, outcome and patterns. Specific projects will determine if genetic diversity, possibly driven by parasites with higher genetic plasticity, plays a role in changing epidemiology, pathogenesis, vector competence of parasite populations, and whether innate human genetic traits protect Indians from malaria today. Deep local clinical knowledge of malaria in India will be supplemented by basic scientists who bring new research tools. Such tools will include whole genome sequencing and analysis methods; in vitro assays to measure genome plasticity, RBC cytoadhesion, invasion, and deformability; mosquito infectivity assays to evaluate changing parasite-vector compatibilities; and host genetics to understand protective traits in Indian populations. The MESA-ICEMR study sites span diagonally across India, including a mixture of very urban and rural hospitals, each with very different disease patterns and patient populations. Research partnerships include government-associated research institutes, private medical schools, city and state government hospitals, and hospitals with industry ties. Between 2012-2017, in addition to developing clinical research and basic science infrastructure at new clinical sites, our training workshops will engage new scientists and clinicians throughout South Asia in the malaria research field. PMID:22266213

Regulation of the resistance to nematode parasites of single- and twin-bearing Merino ewes through nutrition and genetic selection.

PubMed

Kahn, L P; Knox, M R; Walkden-Brown, S W; Lea, J M

2003-05-15

Periparturient Merino ewes obtained from lines of sheep that had been selected either for increased resistance to Haemonchus contortus (R) or at random (C) were supplemented, while grazing at pasture, with either nil or 250 g/day cottonseed meal (CSM) for the 6 weeks prior to or the 6 weeks after the start of parturition. Ewes from both supplement groups had lower (mean 66% reduction) faecal egg counts (FECs) during the postpartum period and this coincided with a period of maternal body weight loss. Factors which increased the rate of maternal body weight loss, such as pregnancy and lactation status, also increased FEC. Evidence is presented that the magnitude of the periparturient rise (PPR) in FEC in grazing ewes will be greatest during periods of maternal weight loss and at these times supplementation to increase metabolisable protein (MP) supply will be most effective in increasing resistance to nematode parasites. The resistance of R ewes to nematode parasites was greater than that of C ewes throughout the experiment and was sufficiently low such that anthelmintic treatment in a commercial environment may not have been required. Irrespective of actual FEC, ewes from all treatment combinations exhibited a PPR in FEC. Reduced FEC of R ewes resulted in reduced apparent pasture larval contamination after 18 weeks of continuous grazing but supplementation was ineffective in this regard. It is suggested that integrated parasite management (IPM) programs for periparturient ewes should make use of both protein supplementation and genetic selection to increase worm resistance and reduce dependency on anthelmintics for worm control.

Ticks collected from humans, domestic animals, and wildlife in Yucatan, Mexico.

PubMed

Rodríguez-Vivas, R I; Apanaskevich, D A; Ojeda-Chi, M M; Trinidad-Martínez, I; Reyes-Novelo, E; Esteve-Gassent, M D; Pérez de León, A A

2016-01-15

Domestic animals and wildlife play important roles as reservoirs of zoonotic pathogens that are transmitted to humans by ticks. Besides their role as vectors of several classes of microorganisms of veterinary and public health relevance, ticks also burden human and animal populations through their obligate blood-feeding habit. It is estimated that in Mexico there are around 100 tick species belonging to the Ixodidae and Argasidae families. Information is lacking on tick species that affect humans, domestic animals, and wildlife through their life cycle. This study was conducted to bridge that knowledge gap by inventorying tick species that infest humans, domestic animals and wildlife in the State of Yucatan, Mexico. Amblyomma ticks were observed as euryxenous vertebrate parasites because they were found parasitizing 17 animal species and human. Amblyomma mixtum was the most eryxenous species found in 11 different animal species and humans. Both A. mixtum and A. parvum were found parasitizing humans. Ixodes near affinis was the second most abundant species parasitizing six animal species (dogs, cats, horses, white-nosed coati, white-tail deer and black vulture) and was found widely across the State of Yucatan. Ixodid tick populations may increase in the State of Yucatan with time due to animal production intensification, an increasing wildlife population near rural communities because of natural habitat reduction and fragmentation. The diversity of ticks across host taxa documented here highlights the relevance of ecological information to understand tick-host dynamics. This knowledge is critical to inform public health and veterinary programs for the sustainable control of ticks and tick-borne diseases. Copyright © 2015. Published by Elsevier B.V.

Potent Plasmodium falciparum gametocytocidal activity of diaminonaphthoquinones, lead antimalarial chemotypes identified in an antimalarial compound screen.

PubMed

Tanaka, Takeshi Q; Guiguemde, W Armand; Barnett, David S; Maron, Maxim I; Min, Jaeki; Connelly, Michele C; Suryadevara, Praveen Kumar; Guy, R Kiplin; Williamson, Kim C

2015-03-01

Forty percent of the world's population is threatened by malaria, which is caused by Plasmodium parasites and results in an estimated 200 million clinical cases and 650,000 deaths each year. Drug resistance has been reported for all commonly used antimalarials and has prompted screens to identify new drug candidates. However, many of these new candidates have not been evaluated against the parasite stage responsible for transmission, gametocytes. If Plasmodium falciparum gametocytes are not eliminated, patients continue to spread malaria for weeks after asexual parasite clearance. Asymptomatic individuals can also harbor gametocyte burdens sufficient for transmission, and a safe, effective gametocytocidal agent could also be used in community-wide malaria control programs. Here, we identify 15 small molecules with nanomolar activity against late-stage gametocytes. Fourteen are diaminonaphthoquinones (DANQs), and one is a 2-imino-benzo[d]imidazole (IBI). One of the DANQs identified, SJ000030570, is a lead antimalarial candidate. In contrast, 94% of the 650 compounds tested are inactive against late-stage gametocytes. Consistent with the ineffectiveness of most approved antimalarials against gametocytes, of the 19 novel compounds with activity against known anti-asexual-stage targets, only 3 had any strong effect on gametocyte viability. These data demonstrate the distinct biology of the transmission stages and emphasize the importance of screening for gametocytocidal activity. The potent gametocytocidal activity of DANQ and IBI coupled with their efficacy against asexual parasites provides leads for the development of antimalarials with the potential to prevent both the symptoms and the spread of malaria. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Strongyloides stercoralis and relatives: recent advances in general and molecular biology.

PubMed

Lok, James B

2014-12-01

Human strongyloidiasis is a threat to global health, presenting significant challenges in diagnosis and clinical management. The imperative to incorporate strongyoidiasis more fully into control programs for soil-transmitted helminths is increasingly recognized. The unique life cycles of S. stercoralis and congeneric species contain both free-living and parasitic generations, and transcriptomic methods have recently identified genes of potential importance to parasitism in these parasites. Proteomics recently revealed stage-specific secreted proteins that appear crucial to the host-parasite interaction. A comprehensive genome sequencing project for Strongyloides spp. is now nearing completion. Recent technical advances in transgenesis for S. stercoralis and S. ratti , including the first establishment of stable transgenic lines, promise to advance functional evaluations of genes expressed in conjunction with crucial life cycle events. Studies employing these methods recently bolstered the hypothesis that S. stercoralis uses cellular signaling pathways homologous to three that regulate dauer larval development in Caenorhabditis elegans to regulate morphogenesis and development of its infective third-stage larva. The free-living generation of Strongyloides makes classical genetics formally possible. Recent advances, such as a genetic map of S. ratti and a molecular genetic and karyotypic analysis of sex determination in S. papillosus , will greatly facilitate this approach. Advanced methods for study of chemosensation in C. elegans were recently applied to discover numerous host attractant molecules that mediate host finding and contact by infective third-stage larvae of Strongyloides spp. Finally, nucleic acid-based diagnostic methods have recently come to the fore as alternatives to parasitological and immunodiagnostic techniques.

An experimental test of host’s life history traits modulation in response to cuckoo parasitism risk

PubMed Central

Parejo, Deseada; Martínez, Juan Gabriel; Sánchez-Tójar, Alfredo; Precioso, Marta; Molina-Morales, Mercedes; Avilés, Jesús M.

2017-01-01

Hosts can counteract parasites through defences based on resistance and/or tolerance. The mechanistic basis of tolerance, which involve defensive mechanisms minimizing parasite damage after a successful parasitic attack, remains poorly explored in the study of cuckoo-host interactions. Here, we experimentally explore the possibility that the risk of great spotted cuckoo Clamator glandarius parasitism may induce tolerance defences in magpie Pica pica hosts through plasticity in life-history traits. We predict that magpies exposed to auditory cues indicating high parasitism risk will more likely exhibit resistance and/or modify their life-history traits to minimize parasitism costs (i.e. tolerance) compared to magpies under low parasitism risk. We found that manipulating the perceived parasitism risk did not affect host resistance (i.e. rejection of parasitic eggs) nor host life-history traits. Unexpectedly, host’s egg volume increased over the season in nests exposed to auditory cues of control non-harmful hoopoes Upupa epops. Our results do not provide support for inducible defences (either based on resistance or tolerance) in response to risk of parasitism in magpie hosts. Even so, we encourage studying plastic expression of breeding strategies in response to risk of cuckoo parasitism to achieve a better understanding of the mechanistic basis of tolerance defences. PMID:28658287

Modeling effective transmission pathways and control of the world's most successful parasite.

PubMed

Turner, Matthew; Lenhart, Suzanne; Rosenthal, Benjamin; Zhao, Xiaopeng

2013-06-01

Toxoplasma gondii(T. gondii) is a single-celled, intracellular protozoan responsible for the disease toxoplasmosis. The parasite is prevalent worldwide, and it infects all warm-blooded vertebrates. Consumption of meats in which this parasite has encysted confers risk of infection to people and other animals, as does ingestion of water or foods contaminated with environmentally resistant oocysts excreted by cats. Vertical transmission (from mother to offspring) is also possible, leading to disease risk and contributing additional means of ensuring perpetuation of transmission. In this work, we adopt a differential equation model to investigate the effective transmission pathways of T. gondii, as well as potential control mechanisms. Detailed analyses are carried out to examine the significance of transmission routes, virulence, vertical transmission, parasite-induced changes in host behavior, and controls based on vaccination and harvesting. Modeling and analysis efforts may shed insights into understanding the complex life cycle of T. gondii. Copyright © 2013 Elsevier Inc. All rights reserved.

The effect of India's total sanitation campaign on defecation behaviors and child health in rural Madhya Pradesh: a cluster randomized controlled trial.

PubMed

Patil, Sumeet R; Arnold, Benjamin F; Salvatore, Alicia L; Briceno, Bertha; Ganguly, Sandipan; Colford, John M; Gertler, Paul J

2014-08-01

Poor sanitation is thought to be a major cause of enteric infections among young children. However, there are no previously published randomized trials to measure the health impacts of large-scale sanitation programs. India's Total Sanitation Campaign (TSC) is one such program that seeks to end the practice of open defecation by changing social norms and behaviors, and providing technical support and financial subsidies. The objective of this study was to measure the effect of the TSC implemented with capacity building support from the World Bank's Water and Sanitation Program in Madhya Pradesh on availability of individual household latrines (IHLs), defecation behaviors, and child health (diarrhea, highly credible gastrointestinal illness [HCGI], parasitic infections, anemia, growth). We conducted a cluster-randomized, controlled trial in 80 rural villages. Field staff collected baseline measures of sanitation conditions, behaviors, and child health (May-July 2009), and revisited households 21 months later (February-April 2011) after the program was delivered. The study enrolled a random sample of 5,209 children <5 years old from 3,039 households that had at least one child <24 months at the beginning of the study. A random subsample of 1,150 children <24 months at enrollment were tested for soil transmitted helminth and protozoan infections in stool. The randomization successfully balanced intervention and control groups, and we estimated differences between groups in an intention to treat analysis. The intervention increased percentage of households in a village with improved sanitation facilities as defined by the WHO/UNICEF Joint Monitoring Programme by an average of 19% (95% CI for difference: 12%-26%; group means: 22% control versus 41% intervention), decreased open defecation among adults by an average of 10% (95% CI for difference: 4%-15%; group means: 73% intervention versus 84% control). However, the intervention did not improve child health measured in terms of multiple health outcomes (diarrhea, HCGI, helminth infections, anemia, growth). Limitations of the study included a relatively short follow-up period following implementation, evidence for contamination in ten of the 40 control villages, and bias possible in self-reported outcomes for diarrhea, HCGI, and open defecation behaviors. The intervention led to modest increases in availability of IHLs and even more modest reductions in open defecation. These improvements were insufficient to improve child health outcomes (diarrhea, HCGI, parasite infection, anemia, growth). The results underscore the difficulty of achieving adequately large improvements in sanitation levels to deliver expected health benefits within large-scale rural sanitation programs. ClinicalTrials.gov NCT01465204. Please see later in the article for the Editors' Summary.

The Effect of India's Total Sanitation Campaign on Defecation Behaviors and Child Health in Rural Madhya Pradesh: A Cluster Randomized Controlled Trial

PubMed Central

Patil, Sumeet R.; Arnold, Benjamin F.; Salvatore, Alicia L.; Briceno, Bertha; Ganguly, Sandipan; Colford, John M.; Gertler, Paul J.

2014-01-01

Background Poor sanitation is thought to be a major cause of enteric infections among young children. However, there are no previously published randomized trials to measure the health impacts of large-scale sanitation programs. India's Total Sanitation Campaign (TSC) is one such program that seeks to end the practice of open defecation by changing social norms and behaviors, and providing technical support and financial subsidies. The objective of this study was to measure the effect of the TSC implemented with capacity building support from the World Bank's Water and Sanitation Program in Madhya Pradesh on availability of individual household latrines (IHLs), defecation behaviors, and child health (diarrhea, highly credible gastrointestinal illness [HCGI], parasitic infections, anemia, growth). Methods and Findings We conducted a cluster-randomized, controlled trial in 80 rural villages. Field staff collected baseline measures of sanitation conditions, behaviors, and child health (May–July 2009), and revisited households 21 months later (February–April 2011) after the program was delivered. The study enrolled a random sample of 5,209 children <5 years old from 3,039 households that had at least one child <24 months at the beginning of the study. A random subsample of 1,150 children <24 months at enrollment were tested for soil transmitted helminth and protozoan infections in stool. The randomization successfully balanced intervention and control groups, and we estimated differences between groups in an intention to treat analysis. The intervention increased percentage of households in a village with improved sanitation facilities as defined by the WHO/UNICEF Joint Monitoring Programme by an average of 19% (95% CI for difference: 12%–26%; group means: 22% control versus 41% intervention), decreased open defecation among adults by an average of 10% (95% CI for difference: 4%–15%; group means: 73% intervention versus 84% control). However, the intervention did not improve child health measured in terms of multiple health outcomes (diarrhea, HCGI, helminth infections, anemia, growth). Limitations of the study included a relatively short follow-up period following implementation, evidence for contamination in ten of the 40 control villages, and bias possible in self-reported outcomes for diarrhea, HCGI, and open defecation behaviors. Conclusions The intervention led to modest increases in availability of IHLs and even more modest reductions in open defecation. These improvements were insufficient to improve child health outcomes (diarrhea, HCGI, parasite infection, anemia, growth). The results underscore the difficulty of achieving adequately large improvements in sanitation levels to deliver expected health benefits within large-scale rural sanitation programs. Trial Registration ClinicalTrials.gov NCT01465204 Please see later in the article for the Editors' Summary PMID:25157929

Mind Control: How Parasites Manipulate Cognitive Functions in Their Insect Hosts

PubMed Central

Libersat, Frederic; Kaiser, Maayan; Emanuel, Stav

2018-01-01

Neuro-parasitology is an emerging branch of science that deals with parasites that can control the nervous system of the host. It offers the possibility of discovering how one species (the parasite) modifies a particular neural network, and thus particular behaviors, of another species (the host). Such parasite–host interactions, developed over millions of years of evolution, provide unique tools by which one can determine how neuromodulation up-or-down regulates specific behaviors. In some of the most fascinating manipulations, the parasite taps into the host brain neuronal circuities to manipulate hosts cognitive functions. To name just a few examples, some worms induce crickets and other terrestrial insects to commit suicide in water, enabling the exit of the parasite into an aquatic environment favorable to its reproduction. In another example of behavioral manipulation, ants that consumed the secretions of a caterpillar containing dopamine are less likely to move away from the caterpillar and more likely to be aggressive. This benefits the caterpillar for without its ant bodyguards, it is more likely to be predated upon or attacked by parasitic insects that would lay eggs inside its body. Another example is the parasitic wasp, which induces a guarding behavior in its ladybug host in collaboration with a viral mutualist. To exert long-term behavioral manipulation of the host, parasite must secrete compounds that act through secondary messengers and/or directly on genes often modifying gene expression to produce long-lasting effects. PMID:29765342

Host protective roles of type 2 immunity: Parasite killing and tissue repair, flip sides of the same coin

PubMed Central

Allen, Judith E.; Sutherland, Tara E.

2014-01-01

Metazoan parasites typically induce a type 2 immune response, characterized by T helper 2 (Th2) cells that produce the cytokines IL-4, IL-5 and IL-13 among others. The type 2 response is host protective, reducing the number of parasites either through direct killing in the tissues, or expulsion from the intestine. Type 2 immunity also protects the host against damage mediated by these large extracellular parasites as they migrate through the body. At the center of both the innate and adaptive type 2 immune response, is the IL-4Rα that mediates many of the key effector functions. Here we highlight the striking overlap between the molecules, cells and pathways that mediate both parasite control and tissue repair. We have proposed that adaptive Th2 immunity evolved out of our innate repair pathways to mediate both accelerated repair and parasite control in the face of continual assault from multicellular pathogens. Type 2 cytokines are involved in many aspects of mammalian physiology independent of helminth infection. Therefore understanding the evolutionary relationship between helminth killing and tissue repair should provide new insight into immune mechanisms of tissue protection in the face of physical injury. PMID:25028340

Prediction and prevention of parasitic diseases using a landscape genomics framework

PubMed Central

Schwabl, Philipp; Llewellyn, Martin; Landguth, Erin L.; Andersson, Björn; Kitron, Uriel; Costales, Jaime A.; Ocaña, Sofía; Grijalva, Mario J.

2016-01-01

Summary Substantial heterogeneity exists in the dispersal, distribution and transmission of parasitic species. Understanding and predicting how such features are governed by the ecological variation of landscape they inhabit is the central goal of spatial epidemiology. Genetic data can further inform functional connectivity among parasite, host and vector populations in a landscape. Gene flow correlates with the spread of epidemiologically relevant phenotypes among parasite and vector populations (e.g., virulence, drug and pesticide resistance), as well as invasion and re-invasion risk where parasite transmission is absent due to current or past intervention measures. However, the formal integration of spatial and genetic data (‘landscape genetics’) is scarcely ever applied to parasites. Here, we discuss the specific challenges and practical prospects for the use of landscape genetics and genomics to understand the biology and control of parasitic disease and present a practical framework for doing so. PMID:27863902

Prediction and Prevention of Parasitic Diseases Using a Landscape Genomics Framework.

PubMed

Schwabl, Philipp; Llewellyn, Martin S; Landguth, Erin L; Andersson, Björn; Kitron, Uriel; Costales, Jaime A; Ocaña, Sofía; Grijalva, Mario J

2017-04-01

Substantial heterogeneity exists in the dispersal, distribution and transmission of parasitic species. Understanding and predicting how such features are governed by the ecological variation of landscape they inhabit is the central goal of spatial epidemiology. Genetic data can further inform functional connectivity among parasite, host and vector populations in a landscape. Gene flow correlates with the spread of epidemiologically relevant phenotypes among parasite and vector populations (e.g., virulence, drug and pesticide resistance), as well as invasion and re-invasion risk where parasite transmission is absent due to current or past intervention measures. However, the formal integration of spatial and genetic data ('landscape genetics') is scarcely ever applied to parasites. Here, we discuss the specific challenges and practical prospects for the use of landscape genetics and genomics to understand the biology and control of parasitic disease and present a practical framework for doing so. Copyright © 2016 Elsevier Ltd. All rights reserved.

Reduction of parasitic lasing

NASA Technical Reports Server (NTRS)

Storm, Mark E. (Inventor)

1994-01-01

A technique was developed which carefully retro-reflects precisely controlled amounts of light back into a laser system thereby intentionally forcing the laser system components to oscillate in a new resonator called the parasitic oscillator. The parasitic oscillator uses the laser system to provide the gain and an external mirror is used to provide the output coupling of the new resonator. Any change of gain or loss inside the new resonator will directly change the lasing threshold of the parasitic oscillator. This change in threshold can be experimentally measured as a change in the absolute value of reflectivity, provided by the external mirror, necessary to achieve lasing in the parasitic oscillator. Discrepancies between experimental data and a parasitic oscillator model are direct evidence of optical misalignment or component performance problems. Any changes in the optical system can instantly be measured as a change in threshold for the parasitic oscillator. This technique also enables aligning the system for maximum parasitic suppression with the system fully operational.

Trade-offs in parasitism efficiency and brood size mediate parasitoid coexistence, with implications for biological control of the invasive emerald ash borer

USDA-ARS?s Scientific Manuscript database

Parasitoids often are selected for use as biological control agents because of their high host specificity, yet such host specificity can result in strong interspecific competition. However, few studies have examined if and how various extrinsic factors (such as parasitism efficiency) influence the ...

Epidemiology and detection as options for control of viral and parasitic foodborne disease.

PubMed Central

Jaykus, L. A.

1997-01-01

Human enteric viruses and protozoal parasites are important causes of emerging food and waterborne disease. Epidemiologic investigation and detection of the agents in clinical, food, and water specimens, which are traditionally used to establish the cause of disease outbreaks, are either cumbersome, expensive, and frequently unavailable or unattempted for the important food and waterborne enteric viruses and protozoa. However, the recent introduction of regulatory testing mandates, alternative testing strategies, and increased epidemiologic surveillance for food and waterborne disease should significantly improve the ability to detect and control these agents. We discuss new methods of investigating foodborne viral and parasitic disease and the future of these methods in recognizing, identifying, and controlling disease agents. PMID:9366607

Evidence for parasite-mediated selection during short-lasting toxic algal blooms.

PubMed

Blanquart, François; Valero, Myriam; Alves-de-Souza, Catharina; Dia, Aliou; Lepelletier, Frédéric; Bigeard, Estelle; Jeanthon, Christian; Destombe, Christophe; Guillou, Laure

2016-10-26

Parasites play a role in the control of transient algal blooms, but it is not known whether parasite-mediated selection results in coevolution of the host and the parasites over this short time span. We investigated the presence of coevolution between the toxic dinoflagellate Alexandrium minutum and two naturally occurring endoparasites during blooms lasting a month in two river estuaries, using cross-inoculation experiments across time and space. Higher parasite abundance was associated with a large daily reduction in relative A. minutum abundances, demonstrating strong parasite-mediated selection. There was genetic variability in infectivity in both parasite species, and in resistance in the host. We found no evidence for coevolution in one estuary; however, in the other estuary, we found high genetic diversity in the two parasite species, fluctuations in infectivity and suggestion that the two parasites are well adapted to their host, as in 'Red Queen' dynamics. Thus, coevolution is possible over the short time span of a bloom, but geographically variable, and may feedback on community dynamics. © 2016 The Authors.

The parasite connection in ecosystems and macroevolution

NASA Astrophysics Data System (ADS)

Seilacher, Adolf; Reif, Wolf-Ernst; Wenk, Peter

2007-03-01

In addition to their obvious negative effects (“pathogens”), endoparasites of various kinds play an important role in shaping and maintaining modern animal communities. In the long-term, parasites including pathogens are indispensable entities of any ecosystem. To understand this, it is essential that one changes the viewpoint from the host’s interests to that of the parasite. Together with geographic isolation, trophic arms race, symbiosis, and niche partitioning, all parasites (including balance strategists, i.e. seemingly non-pathogenic ones) modulate their hosts’ population densities. In addition, heteroxenic parasites control the balance between predator and prey species, particularly if final and intermediate hosts are vertebrates. Thereby, such parasites enhance the bonds in ecosystems and help maintain the status quo. As the links between eukaryotic parasites and their hosts are less flexible than trophic connections, parasite networks probably contributed to the observed stasis and incumbency of ecosystems over geologic time, in spite of continuous Darwinian innovation. Because heteroxenic parasites target taxonomic levels above that of the species (e.g. families), these taxa may have also become units of selection in global catastrophies. Macroevolutionary extrapolations, however, are difficult to verify because endoparasites cannot fossilize.

Shared elements of host-targeting pathways among apicomplexan parasites of differing lifestyles.

PubMed

Pellé, Karell G; Jiang, Rays H Y; Mantel, Pierre-Yves; Xiao, Yu-Ping; Hjelmqvist, Daisy; Gallego-Lopez, Gina M; O T Lau, Audrey; Kang, Byung-Ho; Allred, David R; Marti, Matthias

2015-11-01

Apicomplexans are a diverse group of obligate parasites occupying different intracellular niches that require modification to meet the needs of the parasite. To efficiently manipulate their environment, apicomplexans translocate numerous parasite proteins into the host cell. Whereas some parasites remain contained within a parasitophorous vacuole membrane (PVM) throughout their developmental cycle, others do not, a difference that affects the machinery needed for protein export. A signal-mediated pathway for protein export into the host cell has been characterized in Plasmodium parasites, which maintain the PVM. Here, we functionally demonstrate an analogous host-targeting pathway involving organellar staging prior to secretion in the related bovine parasite, Babesia bovis, a parasite that destroys the PVM shortly after invasion. Taking into account recent identification of a similar signal-mediated pathway in the coccidian parasite Toxoplasma gondii, we suggest a model in which this conserved pathway has evolved in multiple steps from signal-mediated trafficking to specific secretory organelles for controlled secretion to a complex protein translocation process across the PVM. © 2015 John Wiley & Sons Ltd.

RNA translocation between parasitic plants and their hosts.

PubMed

Westwood, James H; Roney, Jeannine K; Khatibi, Piyum A; Stromberg, Verlyn K

2009-05-01

Recent research indicates that RNA translocation occurs between certain parasitic plant species and their hosts. The movement of at least 27 mRNAs has been demonstrated between hosts and Cuscuta pentagona Engelm., with the largest proportion of these being regulatory genes. Movement of RNAi signals has been documented from hosts to the parasites Triphysaria versicolor (Frisch & CA Mey) and Orobanche aegyptiaca (Pers.), demonstrating that the regulation of genes in one species can be influenced by transfer of RNA signals through a parasitic association. This review considers the implications of these findings in light of present understanding of host-parasite connections and the growing body of evidence that RNAs are able to act as signal molecules that convey regulatory information in a cell- and tissue-specific manner. Together, this suggests that parasitic plants can exchange RNAs with their hosts, and that this may be part of the coordinated growth and development that occurs during the process of parasitism. This phenomenon offers promise for new insights into parasitic plants, and new opportunities for the control of parasitic weeds.

Membrane transport in the malaria parasite and its host erythrocyte.

PubMed

Kirk, Kiaran; Lehane, Adele M

2014-01-01

As it grows and replicates within the erythrocytes of its host the malaria parasite takes up nutrients from the extracellular medium, exports metabolites and maintains a tight control over its internal ionic composition. These functions are achieved via membrane transport proteins, integral membrane proteins that mediate the passage of solutes across the various membranes that separate the biochemical machinery of the parasite from the extracellular environment. Proteins of this type play a key role in antimalarial drug resistance, as well as being candidate drug targets in their own right. This review provides an overview of recent work on the membrane transport biology of the malaria parasite-infected erythrocyte, encompassing both the parasite-induced changes in the membrane transport properties of the host erythrocyte and the cell physiology of the intracellular parasite itself.

Current procedures of the integrated urban vector-mosquito control as an example in Cotonou (Benin, West Africa) and Wrocław area (Poland).

PubMed

Rydzanicz, Katarzyna; Lonc, Elzbieta; Becker, Norbert

2009-01-01

Current strategy of Integrated Vector Management (IVM) comprises the general approach of environmentally friendly control measures. With regard to mosquitoes it includes first of all application of microbial insecticides based on Bacillus thuringiensis israelensis (Bti) and B. sphaericus (Bs) delta-endotoxins as well as the reduction of breeding habitats and natural enemy augmentation. It can be achieved thorough implementation of the interdisciplinary program, i. e., understanding of mosquito vector ecology, the appropriate vector-diseases (e. g., malariometric) measurements and training of local personnel responsible for mosquito abatement activities, as well as community involvement. Biocontrol methods as an alternative to chemical insecticides result from the sustainability development concept, growing awareness of environmental pollution and the development of insecticide-resistant strains of vector-mosquito populations in many parts of the world. Although sustainable trends are usually considered in terms of the monetary and training resources within countries, environmental concerns are actually more limiting factors for the duration of an otherwise successful vector control effort. In order to meet these new needs, increasing efforts have been made in search of and application of natural enemies, such as parasites, bacterial pathogens and predators which may control populations of insect vectors. The biological control agent based on the bacterial toxins Bti and Bs has been used in the Wrocław's University and Municipal Mosquito Control Programs since 1998. In West-Africa biocontrol appears to be an effective and safe tool to combat malaria in addition to bed-nets, residual indoor spraying and appropriate diagnosis and treatment of malaria parasites which are the major tools in the WHO Roll Back Malaria Program. IVM studies carried out 2005-2008 in Cotonou (Benin) as well those in Wrocław Irrigated Fields during the last years include the following major steps: 1. Mapping of all breeding sites in the project area and recording data in a geographical information system (GIS/relational database). All districts, streets and houses are numbered for quick reference during the operation; 2. Studying mosquito vector bionomics, migration and vectorial capacity in the project area, before, during and after the routine Bti treatments; 3. Assessment of the optimum for effective larvicide insecticide dosages at major breeding sites against the different target mosquito species; 4. Implementation of the microbial control agents in the integrated routine program. Adaptation of the application equipment to the local situation, training of the field staff, and routine treatments; 5. Conducting surveillance of vector-disease (e. g., malariometric) parameters in the control and experimental area before, during, and after the application of biocontrol agents.

Obligate brood parasites show more functionally effective innate immune responses: an eco-immunological hypothesis

USGS Publications Warehouse

Hahn, D. Caldwell; Summers, Scott G.; Genovese, Kenneth J.; He, Haiqi; Kogut, Michael H.

2013-01-01

Immune adaptations of obligate brood parasites attracted interest when three New World cowbird species (Passeriformes, Icteridae, genus Molothrus) proved unusually resistant to West Nile virus. We have used cowbirds as models to investigate the eco-immunological hypothesis that species in parasite-rich environments characteristically have enhanced immunity as a life history adaptation. As part of an ongoing program to understand the cowbird immune system, in this study we measured degranulation and oxidative burst, two fundamental responses of the innate immune system. Innate immunity provides non-specific, fast-acting defenses against a variety of invading pathogens, and we hypothesized that innate immunity experiences particularly strong selection in cowbirds, because their life history strategy exposes them to diverse novel and unpredictable parasites. We compared the relative effectiveness of degranulation and oxidative burst responses in two cowbird species and one related, non-parasitic species. Both innate immune defenses were significantly more functionally efficient in the two parasitic cowbird species than in the non-parasitic red-winged blackbird (Icteridae, Agelaius phoeniceus). Additionally, both immune defenses were more functionally efficient in the brown-headed cowbird (M. ater), an extreme host-generalist brood parasite, than in the bronzed cowbird (M. aeneus), a moderate host-specialist with lower exposure to other species and their parasites. Thus the relative effectiveness of these two innate immune responses corresponds to the diversity of parasites in the niche of each species and to their relative resistance to WNV. This study is the first use of these two specialized assays in a comparative immunology study of wild avian species.

Questionnaire study on parasite control practices on Thoroughbred and Standardbred breeding farms in New Zealand.

PubMed

Bolwell, Charlotte F; Rosanowski, Sarah M; Scott, Ian; Sells, Patrick D; Rogers, Chris W

2015-04-15

Against a global background of increasing anthelmintic resistance in parasites, little is known about the current parasite control strategies adopted within the equine industry in New Zealand. The aim of the study was to describe and compare the current parasite management and control practices used on Thoroughbred and Standardbred stud farms in New Zealand. An online questionnaire was used to collect data on the demographics of respondents, parasite control methods, grazing management, and use of faecal egg counts. Questions regarding parasite control strategy, how often horses were dewormed, number of treatments per year and stocking density were stratified by horse type: young stock (foals/weanlings/yearlings), wet mares (nursing a foal) or dry mares, and industry (Thoroughbred and Standardbred). Questions on grazing management were stratified by horse type and the breeding and non-breeding season. In total, 136 respondents completed the survey, of which most (66%; 90/136) were involved in the Thoroughbred breeding industry. Most (98%; 134/136) respondents used anthelmintic products to treat the horses on their property, and regardless of industry type most respondents were using interval drenching for young stock (86/129; 53%), dry mares (51/124; 41%) or wet mares (50/126; 40%). Of those respondents treating on regular interval, 55% (68/123), 42% (50/119) and 38% (46/122) were treating young stock, wet mares and dry mares every 6-8 weeks. The median number of treatments per year for young stock, dry mares and wet mares was 6 (IQR 4-8), 4 (IQR 3-6) and 4 (IQR 3-6), respectively; there was no difference in frequency of treatments by industry type. In the last 12 months respondents used a median of 2 (IQR 2-4) and 3 (IQR 2-4) different anthelmintic products to treat horses on Thoroughbred and Standardbred breeding farms, respectively. Of the respondents reporting the anthelmintic products used in the last 12 months, 95% used at least one product containing macrocyclic lactones. Overall, faecal egg counts were done by 20% (25/124) of respondents and over half of respondents in both industries were consulting their veterinarian for advice on worming products. This study identified a high reliance on anthelmintic products and limited on-farm control practices that would delay the development of anthelmintic resistance in equine parasites. Further research is now required to identify the level of resistance in the New Zealand equine parasite population. Copyright © 2015 Elsevier B.V. All rights reserved.

[The effect of ivermectin on geohelminth frequency (i.e. as used in the onchocerciasis control program in Colombia)].

PubMed

Knudson, Angélica; Ariza, Yoseth; López, Myriam C; Fajardo, Oscar S; Reyes, Patricia; Moncada, Ligia I; Duque, Sofía; Álvarez, Carlos A; Nicholls, Rubén S

2012-08-01

Evaluating the effect of ivermectin on soil-transmitted helminthes (STH) infection frequency in a Colombian population included in the Onchocerciasis Elimination Program for the Americas (OEPA). This was an impact evaluation study which adopted a longitudinal approach using the population of Naicioná (1996) as baseline for comparison to people from the same population as controls (2008). The cross-sectional approach involved comparing the reference population of Naicioná (2008) to the population of Dos Quebradas (2008) used as controls. Fecal samples were processed by a modified Ritchie-Frick method. Ascaris lumbricoides was the most frequently found parasite in Naicioná (60/121; 49.6 %: 37.8-63.895%CI) and in Dos Quebradas (36/76; 47.4 %: 33.2-65.6 95 % CI). Ivermectin's main effect on the population aged over 5 years was a decreased risk of Trichiuris trichiura infection in both longitudinal assessment (86 % reduction: 74-93 95 % CI) and cross-sectional assessment (63 %:24-82 95 % CI). A 93 % reduction (45-99 95 % CI) in Strongyloides stercoralis frequency was found in longitudinal assessment, compared to 85 % in cross-sectional assessment (-031-99 95 % CI). Ivermectin use in the OEPA is not sufficient for STH morbidity control. Integrated programs including education and basic sanitation are required.

Impact of integrated gastrointestinal nematode management training for U.S. goat and sheep producers.

PubMed

Whitley, N C; Oh, S-H; Lee, S J; Schoenian, S; Kaplan, R M; Storey, B; Terrill, T H; Mobini, S; Burke, J M; Miller, J E; Perdue, M A

2014-03-01

The objective of this study was to determine the impact of integrated parasite management (IPM) training, including FAMACHA(©) eyelid color scoring, on the ability of U.S. sheep and goat producers to control gastrointestinal nematodes (GIN) on their farms. A survey was developed and provided to over 2000 producers trained from 2004 to 2008 in IPM with questions involving farm size (number of sheep/goats), location (U.S. state), impact of training on parasite control efforts and parasite problems on farm, and IPM practices used. Responses were divided into U.S. Census regions of the U.S. Descriptive statistics and logistic regression were used to describe results. Most of the 729 respondents were from the southern region of the U.S. (54.3%) and were small-scale producers (50 or less animals; 64.8%). Nearly all of the respondents (95.1%) agreed that IPM workshop attendance made a difference in their ability to control and monitor parasitism in their herd or flock and employed IPM practices to control GIN (96.3%). The most popular practices respondents used were rotational grazing (71.2%), genetic selection (choosing a parasite resistant breed and/or culling susceptible animals; 52.7%), grain supplementation on pasture to improve nutrition (44.0%), and increased height of plants being grazed (41.8%). Although reporting using a practice decreased (P<0.05) the likelihood of reporting fewer problems, for each 1-point increase in the number of practices which producers employed to control internal parasitism in their herd or flock, they were 16% more likely to report fewer GIN problems (P<0.05). Approximately 75% of respondents indicated an economic benefit of IPM on their farm (P<0.05), and those reporting savings of over $80 were more likely to report fewer problems (P<0.05) with parasites after the training while those reporting no economic benefit were less likely to report fewer problems with GIN (P<0.001). Overall, IPM training resulted in positive impacts for producers responding to the survey and should continue. Copyright © 2013 Elsevier B.V. All rights reserved.

Can Interactions Between an Omnivorous Hemipteran and an Egg Parasitoid Limit the Level of Biological Control for the Tomato Pinworm?

PubMed

Cabello, Tomas; Bonfil, Francisco; Gallego, Juan R; Fernandez, Francisco J; Gamez, Manuel; Garay, Jozsef

2015-02-01

Relationships between the omnivorous predator Nesidiocoris tenuis (Reuter) and the egg parasitoid Trichogramma achaeae Nagaraja and Nagarkatti were studied in the laboratory (no-choice and choice assays, and functional responses) and in a greenhouse experiment. Both natural enemies are utilized in the biological control of tomato pinworm on greenhouse-grown tomato crops. Three different food items were offered to the predator: nonparasitized prey, prey parasitized for less than 4 d by T. achaeae, and prey parasitized for more than 4 d by the parasitoid. There were significant differences in consumption of food types, with highest consumption for nonparasitized prey, followed by parasitized (<4 d) and then parasitized (>4 d), both in no-choice and choice trials. At the same time, the predator causes a significant mortality in the prey (over 80%) regardless of previous parasitism, resulting in a very coincidental intraguild predation detrimental to the parasitoid. It has also been observed that there was a change in the functional response by the predator from Type II in presence of nonparasitized prey to Type I when there was a combination of parasitized and nonparasitized prey. This represents an increase of instantaneous search rate (a') and a decrease of handling time (Th), which indicates a change in feeding behavior on the two prey types. Under greenhouse conditions, the intraguild predation reduced the percentage of parasitism by T. achaeae in just over 20%. However, when both natural enemies were present, a better control of pest Tuta absoluta (Meyrick) was achieved than in the case of application of any of them alone. © The Author 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Efficacy of a mermithid nematode Romanomermis iyengari (Welch) (Nematoda: Mermithidae) in controlling tree hole-breeding mosquito Aedes albopictus (Skuse) (Diptera: Culicidae) in a rubber plantation area of Kerala, India.

PubMed

Paily, K P; Chandhiran, K; Vanamail, P; Kumar, N Pradeep; Jambulingam, P

2013-03-01

In rubber plantations, tree holes are one of the major types of breeding habitats of Aedes mosquitoes which transmit dengue and chikungunya. A mermithid nematode, Romanomermis iyengari, was evaluated in tree holes for its efficacy in controlling Aedes albopictus. Infection of mosquito larvae by the nematode was determined through microscopic examination on the next day of application, and evaluation of immature density of mosquito was done on the seventh day. After application of the infective stage of the nematode in a host-parasite ratio of 1:3 or 1:4, the infection rates on the different larval instars of mosquito were similar, 85.7-95.8 % in first to third instars and 79.3 % in fourth instar larvae or 100 and 92.9 %, respectively. Parasite burden varied from 1.1 to 2.4, respectively, among first and third instar larvae applied at 1:3. At 1:4, the parasite burden was between 1.6 (fourth instar) and 4 (second instar). The increase in parasite burden due to parasite density was significant in all the larval instars (P < 0.05). High parasite burden is detrimental to parasite recycling as it can cause premature mortality of the host. Hence, the dosage of 1:3 could be considered as suitable for rubber tree hole habitats. In the nematode-applied tree holes, there was a significant level (P < 0.05) of reduction in the immature density of A. albopictus, especially late instars and pupae, confirming the efficacy of R. iyengari in infecting the mosquito and controlling pupal emergence.

Therapeutic PD-L1 and LAG-3 blockade rapidly clears established blood-stage Plasmodium infection

PubMed Central

Butler, Noah S.; Moebius, Jacqueline; Pewe, Lecia L.; Traore, Boubacar; Doumbo, Ogobara K.; Tygrett, Lorraine T.; Waldschmidt, Thomas J.; Crompton, Peter D.; Harty, John T.

2011-01-01

Plasmodium infection of erythrocytes induces clinical malaria. Parasite-specific CD4+ T cells correlate with reduced parasite burdens and severity of human malaria, and are required to control blood-stage infection in mice. However, the characteristics of CD4+ T cells that determine protection or parasite persistence remain unknown. Here we show that P. falciparum infection of humans increased expression of an inhibitory receptor (PD-1) associated with T cell dysfunction. In vivo blockade of PD-L1 and LAG-3 restored CD4+ T cell function, amplified T follicular helper cell and germinal center B cell and plasmablast numbers, enhanced protective antibodies and rapidly cleared blood-stage malaria in mice. Thus, chronic malaria drives specific T cell dysfunction, which can be rescued to enhance parasite control using inhibitory therapies. PMID:22157630

Prevalences of gastrointestinal parasites in sheep and parasite-control practices in NW Spain.

PubMed

Pedreira, J; Paz-Silva, A; Sánchez-Andrade, R; Suárez, J L; Arias, M; Lomba, C; Díaz, P; López, C; Díez-Baños, P; Morrondo, P

2006-07-17

A coprological survey to know the presence of gastro-intestinal nematode parasites infecting sheep was done in Galicia (NW Spain), an area with Atlantic climate where sheep production is replacing cattle due to the Agricultural Community Politics of the European Union. From September 2001 to November 2002, 1710 faecal samples were randomly collected from 49 sheep farms and examined by using the flotation technique to determine the prevalence of gastro-intestinal nematode parasites. The sheep-level prevalence was 100%, and the genera identified were Chabertia, Cooperia, Haemonchus, Nematodirus, Oesophagostomum, Teladorsagia, Trichostrongylus and Trichuris spp. A questionnaire was distributed to the farmers (at the same time as sampling) about parasite-control practices during the year before sampling (2000). Ninety percent (95% CI 81%, 98%) of the farmers said they used antiparasitic drugs occasionally, but none of them asked for a coprological analysis prior to the treatment and the efficacy of the drugs was never evaluated. A higher median EPG was observed in the treated sheep (163) than in the untreated ones (26). Chemotherapy was the only parasite-control practice. Flocks that treated according to the farmer's previous experience had higher median EPG (236) than other flocks (185 following the prescription of their veterinary clinician and 232 based on the commercial agent's counsel). Typically, one benzimidazole-treatment per year was applied in autumn and non-veterinary counsel was used. Sheep treated with imidotiazoles had lower EPG (144) than other drugs (164 for the benzimidazoles and 166 for the macrocyclic lactones). We found a higher median EPG in the sheep receiving two treatments/year (175) than in those treated only once per year (156). These results suggest lack of knowledge about worm-control strategies and anthelmintic use or unwillingness to apply such knowledge.

Efficacy of an energy block containing Duddingtonia flagrans in the control of gastrointestinal nematodes of sheep.

PubMed

Sagüés, María F; Fusé, Luis A; Fernández, Alicia S; Iglesias, Lucía E; Moreno, Fabiana C; Saumell, Carlos A

2011-09-01

The efficacy of the nematode-trapping fungus Duddingtonia flagrans incorporated into an energy block was evaluated for the control of gastrointestinal nematodes in sheep. Four naturally parasitised sheep with average nematode egg counts of 2,470 eggs per gram grazed by pairs on two similar parasite-free paddocks for 30 days. During that period, one pair of sheep (treated animals, T1) received an energy block containing chlamydospores of D. flagrans at a dose of 200,000 chlamydopores/kg bw/day, while the second pair (control animals, C1) received a fungus-free energy block. The animals in both groups were taken off the paddocks after contaminating the pastures for a month with either nematode eggs plus fungal chlamydospores (T1) or nematode eggs alone (C1). Twelve parasite-free sheep were divided into two groups of six animals each, the treated group (T2) was placed on the paddock previously contaminated with parasites and fungus, while the control group (C2) was placed on the parasite-only paddock. These two groups grazed on their respective paddocks during 30 days and were then housed for 15 days, after which period they were slaughtered in order to determine the parasite burden present in each animal. Results showed that animals in group T2 harboured significantly less nematodes than their counterpart in group C2. The efficacy of D. flagrans was 92% against the total parasite burden, 100% against Haemonchus contortus and Teladorsagia circumcincta, 89.9% against Trichostrongylus colubriformis, 87.5% against Cooperia onchopora, and 90% against Trichostrongylus axei. No efficacy was detected against Nematodirus spathiger, Trichuris ovis and T. skrjabini.

Comparison of statistical models to estimate parasite growth rate in the induced blood stage malaria model.

PubMed

Wockner, Leesa F; Hoffmann, Isabell; O'Rourke, Peter; McCarthy, James S; Marquart, Louise

2017-08-25

The efficacy of vaccines aimed at inhibiting the growth of malaria parasites in the blood can be assessed by comparing the growth rate of parasitaemia in the blood of subjects treated with a test vaccine compared to controls. In studies using induced blood stage malaria (IBSM), a type of controlled human malaria infection, parasite growth rate has been measured using models with the intercept on the y-axis fixed to the inoculum size. A set of statistical models was evaluated to determine an optimal methodology to estimate parasite growth rate in IBSM studies. Parasite growth rates were estimated using data from 40 subjects published in three IBSM studies. Data was fitted using 12 statistical models: log-linear, sine-wave with the period either fixed to 48 h or not fixed; these models were fitted with the intercept either fixed to the inoculum size or not fixed. All models were fitted by individual, and overall by study using a mixed effects model with a random effect for the individual. Log-linear models and sine-wave models, with the period fixed or not fixed, resulted in similar parasite growth rate estimates (within 0.05 log 10 parasites per mL/day). Average parasite growth rate estimates for models fitted by individual with the intercept fixed to the inoculum size were substantially lower by an average of 0.17 log 10 parasites per mL/day (range 0.06-0.24) compared with non-fixed intercept models. Variability of parasite growth rate estimates across the three studies analysed was substantially higher (3.5 times) for fixed-intercept models compared with non-fixed intercept models. The same tendency was observed in models fitted overall by study. Modelling data by individual or overall by study had minimal effect on parasite growth estimates. The analyses presented in this report confirm that fixing the intercept to the inoculum size influences parasite growth estimates. The most appropriate statistical model to estimate the growth rate of blood-stage parasites in IBSM studies appears to be a log-linear model fitted by individual and with the intercept estimated in the log-linear regression. Future studies should use this model to estimate parasite growth rates.

Density of the Waterborne Parasite Ceratomyxa shasta and Its Biological Effects on Salmon

PubMed Central

Ray, R. Adam; Hurst, Charlene N.; Holt, Richard A.; Buckles, Gerri R.; Atkinson, Stephen D.

2012-01-01

The myxozoan parasite Ceratomyxa shasta is a significant pathogen of juvenile salmonids in the Pacific Northwest of North America and is limiting recovery of Chinook (Oncorhynchus tshawytscha) and coho (O. kisutch) salmon populations in the Klamath River. We conducted a 5-year monitoring program that comprised concurrent sentinel fish exposures and water sampling across 212 river kilometers of the Klamath River. We used percent mortality and degree-days to death to measure disease severity in fish. We analyzed water samples using quantitative PCR and Sanger sequencing, to determine total parasite density and relative abundance of C. shasta genotypes, which differ in their pathogenicity to salmonids. We detected the parasite throughout the study zone, but parasite density and genetic composition fluctuated spatially and temporally. Chinook and coho mortality increased with density of their specific parasite genotype, but mortality-density thresholds and time to death differed. A lethality threshold of 40% mortality was reached with 10 spores liter−1 for Chinook but only 5 spores liter−1 for coho. Parasite density did not affect degree-days to death for Chinook but was negatively correlated for coho, and there was wider variation among coho individuals. These differences likely reflect the different life histories and genetic heterogeneity of the salmon populations. Direct quantification of the density of host-specific parasite genotypes in water samples offers a management tool for predicting host population-level impacts. PMID:22407689

Parasite Removal, but Not Herbivory, Deters Future Parasite Attachment on Tomato

PubMed Central

Tjiurutue, Muvari Connie; Palmer-Young, Evan C.; Adler, Lynn S.

2016-01-01

Plants face many antagonistic interactions that occur sequentially. Often, plants employ defense strategies in response to the initial damage that are highly specific and can affect interactions with subsequent antagonists. In addition to herbivores and pathogens, plants face attacks by parasitic plants, but we know little about how prior herbivory compared to prior parasite attachment affects subsequent host interactions. If host plants can respond adaptively to these different damage types, we predict that prior parasitism would have a greater deterrent effect on subsequent parasites than would prior herbivory. To test the effects of prior parasitism and prior herbivory on subsequent parasitic dodder (Cuscuta spp.) preference, we conducted two separate greenhouse studies with tomato hosts (Solanum lycopersicum). In the first experiment, we tested the effects of previous dodder attachment on subsequent dodder preference on tomato hosts using three treatments: control plants that had no previous dodder attachment; dodder-removed plants that had an initial dodder seedling attached, removed and left in the same pot to simulate parasite death; and dodder-continuous plants with an initial dodder seedling that remained attached. In the second experiment, we tested the effects of previous caterpillar damage (Spodoptera exigua) and mechanical damage on future dodder attachment on tomato hosts. Dodder attached most slowly to tomato hosts that had dodder plants previously attached and then removed, compared to control plants or plants with continuous dodder attachment. In contrast, herbivory did not affect subsequent dodder attachment rate. These results indicate that dodder preference depended on the identity and the outcome of the initial attack, suggesting that early-season interactions have the potential for profound impacts on subsequent community dynamics. PMID:27529694

Parasite-altered feeding behavior in insects: integrating functional and mechanistic research frontiers.

PubMed

Bernardo, Melissa A; Singer, Michael S

2017-08-15

Research on parasite-altered feeding behavior in insects is contributing to an emerging literature that considers possible adaptive consequences of altered feeding behavior for the host or the parasite. Several recent ecoimmunological studies show that insects can adaptively alter their foraging behavior in response to parasitism. Another body of recent work shows that infection by parasites can change the behavior of insect hosts to benefit the parasite; manipulations of host feeding behavior may be part of this phenomenon. Here, we address both the functional and the underlying physiological frontiers of parasite-altered feeding behavior in order to spur research that better integrates the two. Functional categories of parasite-altered behavior that are adaptive for the host include prophylaxis, therapy and compensation, while host manipulation is adaptive for the parasite. To better understand and distinguish prophylaxis, therapy and compensation, further study of physiological feedbacks affecting host sensory systems is especially needed. For host manipulation in particular, research on mechanisms by which parasites control host feedbacks will be important to integrate with functional approaches. We see this integration as critical to advancing the field of parasite-altered feeding behavior, which may be common in insects and consequential for human and environmental health. © 2017. Published by The Company of Biologists Ltd.

Chick loss from mixed broods reflects severe nestmate competition between an evictor brood parasite and its hosts.

PubMed

Moskát, Csaba; Hauber, Márk E

2010-03-01

Hatchlings of the obligate brood parasite common cuckoo Cuculus canorus typically evict eggs and nestmates but, rarely, host and parasite nestlings may grow up together. As part of previous experiments, we manipulated host clutches by inducing two great reed warbler Acrocephalus arundinaceus and one parasite young to share a nest from 4 days posthatch, when the cuckoo's eviction behaviour is thought to cease. We documented that in mixed broods typically at least one nestling eventually fell out of nest during the period of 5-10 days posthatch. In 83% of nests one or two host chicks disappeared, and in 17% of nests parasite chicks were lost. All nestlings remained in control broods of three hosts or one parasite. These results imply strong physical competition for space in mixed broods. We suggest that continued foster care for parasitized broods may occasionally be beneficial because host nestlings have some chance to escape the costs of parasitism, even when their parents fail to reject the parasite's egg and the parasite hatchling fails to evict nestmates. Conversely, evictor parasite chicks benefit not only through improved growth, as reported before, but also through the elimination of nestmate competition for space and the risk of displacement from mixed broods. Copyright (c) 2010 Elsevier B.V. All rights reserved.

[Parasites and cancer: is there a causal link?

PubMed

Cheeseman, Kevin; Certad, Gabriela; Weitzman, Jonathan B

2016-10-01

Over 20 % of cancers have infectious origins, including well-known examples of microbes such as viruses (HPV, EBV) and bacteria (H. pylori). The contribution of intracellular eukaryotic parasites to cancer etiology is largely unexplored. Epidemiological and clinical reports indicate that eukaryotic protozoan, such as intracellular apicomplexan that cause diseases of medical or economic importance, can be linked to various cancers: Theileria and Cryptosporidium induce host cell transformation while Plasmodium was linked epidemiologically to the "African lymphoma belt" over fifty years ago. These intracellular eukaryotic parasites hijack cellular pathways to manipulate the host cell epigenome, cellular machinery, signaling pathways and epigenetic programs and marks, such as methylation and acetylation, for their own benefit. In doing so, they tinker with the same pathways as those deregulated during cancer onset. Here we discuss how epidemiological evidence linking eukaryotic intracellular parasites to cancer onset are further strengthened by recent mechanistic studies in three apicomplexan parasites. © 2016 médecine/sciences – Inserm.

Impairment of T Cell Function in Parasitic Infections

PubMed Central

Rodrigues, Vasco; Cordeiro-da-Silva, Anabela; Laforge, Mireille; Ouaissi, Ali; Akharid, Khadija; Silvestre, Ricardo; Estaquier, Jérôme

2014-01-01

In mammals subverted as hosts by protozoan parasites, the latter and/or the agonists they release are detected and processed by sensors displayed by many distinct immune cell lineages, in a tissue(s)-dependent context. Focusing on the T lymphocyte lineage, we review our present understanding on its transient or durable functional impairment over the course of the developmental program of the intracellular parasites Leishmania spp., Plasmodium spp., Toxoplasma gondii, and Trypanosoma cruzi in their mammalian hosts. Strategies employed by protozoa to down-regulate T lymphocyte function may act at the initial moment of naïve T cell priming, rendering T cells anergic or unresponsive throughout infection, or later, exhausting T cells due to antigen persistence. Furthermore, by exploiting host feedback mechanisms aimed at maintaining immune homeostasis, parasites can enhance T cell apoptosis. We will discuss how infections with prominent intracellular protozoan parasites lead to a general down-regulation of T cell function through T cell anergy and exhaustion, accompanied by apoptosis, and ultimately allowing pathogen persistence. PMID:24551250

Fifty Years of the Korean Society for Parasitology

PubMed Central

2009-01-01

In 1959, the Korean Society for Parasitology was founded by clinical scientists, specialists of public health, and 5 core parasitologists with experience in American science and medicine. The Society this year celebrates its 50th anniversary. Due to public health importance at the time of foundation, medical parasitology was the main stream for next 3 decades. Domestic problems of niche parasitic diseases, unlisted in 6 tropical diseases of major importance, had been studied by own efforts. To cope with the demand of parasite control, evaluation system for control activity was built up. Control activity against soil-transmitted nematodes, conducted for almost 3 decades, was evaluated as a success. Evaluation of praziquantel efficacy for clonorchiasis, paragonimiasis, and neurocysticercosis, population dynamics of Ascaris lumbricoides infection in a situation of continuous reinfections, diagnostic modalities of antibody tests combined with brain imaging developed for helminthiasis of the central nervous system and researches on intestinal trematodes were achievements in the first 30 years. During the recent 2 decades, science researches, such as cell and molecular biology of parasites and immunology of parasitic infections have been studied especially on parasitic allergens and proteolytic and anti-oxidant enzymes. Experiences of international cooperation for world health have been accumulated and would be expanded in the future. PMID:19885338

Novel Mutations in the Voltage-Gated Sodium Channel of Pyrethroid-Resistant Varroa destructor Populations from the Southeastern USA.

PubMed

González-Cabrera, Joel; Rodríguez-Vargas, Sonia; Davies, T G Emyr; Field, Linda M; Schmehl, Daniel; Ellis, James D; Krieger, Klemens; Williamson, Martin S

2016-01-01

The parasitic mite Varroa destructor has a significant worldwide impact on bee colony health. In the absence of control measures, parasitized colonies invariably collapse within 3 years. The synthetic pyrethroids tau-fluvalinate and flumethrin have proven very effective at managing this mite within apiaries, but intensive control programs based mainly on one active ingredient have led to many reports of pyrethroid resistance. In Europe, a modification of leucine to valine at position 925 (L925V) of the V. destructor voltage-gated sodium channel was correlated with resistance, the mutation being found at high frequency exclusively in hives with a recent history of pyrethroid treatment. Here, we identify two novel mutations, L925M and L925I, in tau-fluvalinate resistant V. destructor collected at seven sites across Florida and Georgia in the Southeastern region of the USA. Using a multiplexed TaqMan® allelic discrimination assay, these mutations were found to be present in 98% of the mites surviving tau-fluvalinate treatment. The mutations were also found in 45% of the non-treated mites, suggesting a high potential for resistance evolution if selection pressure is applied. The results from a more extensive monitoring programme, using the Taqman® assay described here, would clearly help beekeepers with their decision making as to when to include or exclude pyrethroid control products and thereby facilitate more effective mite management programmes.

“Koko et les lunettes magiques”: An educational entertainment tool to prevent parasitic worms and diarrheal diseases in Côte d’Ivoire

PubMed Central

Kouamé, Abel; Dongo, Kouassi; Yapi, Richard B.; Moro, Honorine M.; Kouakou, Christiane A.; Palmeirim, Marta S.; Bonfoh, Bassirou; N’Goran, Eliézer K.; Utzinger, Jürg

2017-01-01

Background Integrated control programs, emphasizing preventive chemotherapy along with health education, can reduce the incidence of soil-transmitted helminthiasis and schistosomiasis. The aim of this study was to develop an educational animated cartoon to improve school children’s awareness regarding soil-transmitted helminthiasis, diarrheal diseases, and related hygiene practices in Côte d’Ivoire. The key messages included in the cartoon were identified through prior formative research to specifically address local knowledge gaps. Methodology In a first step, preliminary research was conducted to assess the knowledge, attitudes, practices, and beliefs of school-aged children regarding parasitic worm infections and hygiene, to identify key health messages to be included in an animated cartoon. Second, an animated cartoon was produced, which included the drafting of the script and story board, and the production of the cartoon’s initial version. Finally, the animated cartoon was pilot tested in eight selected schools and further fine-tuned. Principal findings According to the questionnaire results, children believed that the consumption of sweet food, eating without washing their hands, sitting on the floor, and eating spoiled food were the main causes of parasitic worm infections. Abdominal pain, diarrhea, lack of appetite, failure to grow, and general fatigue were mentioned as symptoms of parasitic worm infections. Most of the children knew that they should go to the hospital for treatment if they experienced symptoms of parasitic worm diseases. The animated cartoon titled “Koko et les lunettes magiques” was produced by Afrika Toon, in collaboration with a scientific team composed of epidemiologists, civil engineers, and social scientists, and the local school children and teachers. Pilot testing of the animated cartoon revealed that, in the short term, children grasped and kept key messages. Most of the children who were shown the cartoon reported to like it. Acceptance of the animated cartoon was high among children and teachers alike. The messaging was tailored to improve knowledge and practices for prevention of helminthiases and diarrheal diseases through prior identification of knowledge gaps. Integration of such education tools into the school curriculum, along with deworming campaigns, might improve sustainability of control and elimination efforts against helminthiases and diarrheal diseases. PMID:28934198

Recovery of Anisakid larvae by means of chloro-peptic digestion and proposal of the method for the official control.

PubMed

Fraulo, Pasquale; Morena, Carmelo; Costa, Antonella

2014-10-01

Anisakidae larvae belonging to the genera Anisakis and Pseudoterranova, are the most responsible for zoonosis transmitted by fish products (anisakidosis). Acquired by the consumption of raw or undercooked marine fish or squid, the anisakid larvae may cause pathogenic diseases like gastric or intestinal anisakiasis and gastro-allergic disorders. In accordance with current EU legislation, the fresh fish products must be inspected visually in order to detect the possible presence of visible parasites. It is recognized that the visual method is not accurate enough to detect the larvae of parasites in food preparations containing raw or practically raw seafood and it clearly emerges that the official system of control needs to be able to utilise an most efficient analytical technique. In this work, the authors have drawn up and validated an analytical method, which involves artificial digestion and the use of a heated magnetic stirrer, based on the EU Regulation n. 2075/2005. The larvae isolated are then subjected to morphological identification at genus level by using optical microscope. The method, proved to be suitable for the detection of live and dead larvae of anisakidae in ready-to-eat foodstuffs containing raw fish or cephalopods and it is fast and accurate. The method showed high levels of sensitivity and specificity, and the suitability of its use in official food control was confirmed. Its use should be incorporated systematically into specific monitoring programs for the control of foodstuffs containing raw fish products.

Mice deficient in LRG-47 display enhanced susceptibility to Trypanosoma cruzi infection associated with defective hemopoiesis and intracellular control of parasite growth.

PubMed

Santiago, Helton C; Feng, Carl G; Bafica, Andre; Roffe, Ester; Arantes, Rosa M; Cheever, Allen; Taylor, Gregory; Vieira, Leda Q; Vierira, Leda Q; Aliberti, Julio; Gazzinelli, Ricardo T; Sher, Alan

2005-12-15

IFN-gamma is known to be required for host control of intracellular Trypanosoma cruzi infection in mice, although the basis of its protective function is poorly understood. LRG-47 is an IFN-inducible p47GTPase that has been shown to regulate host resistance to intracellular pathogens. To investigate the possible role of LRG-47 in IFN-gamma-dependent control of T. cruzi infection, LRG-47 knockout (KO) and wild-type (WT) mice were infected with the Y strain of this parasite, and host responses were analyzed. When assayed on day 12 after parasite inoculation, LRG-47 KO mice, in contrast to IFN-gamma KO mice, controlled early parasitemia almost as effectively as WT animals. However, the infected LRG-47 KO mice displayed a rebound in parasite growth on day 15, and all succumbed to the infection by day 19. Additional analysis indicated that LRG-47-deficient mice exhibit unimpaired proinflammatory responses throughout the infection. Instead, reactivated disease in the KO animals was associated with severe splenic and thymic atrophy, anemia, and thrombocytopenia not observed in their WT counterparts. In addition, in vitro studies revealed that IFN-gamma-stimulated LRG-47 KO macrophages display defective intracellular killing of amastigotes despite normal expression of TNF and NO synthetase type 2 and that both NO synthetase type 2 and LRG-47 are required for optimum IFN-gamma-dependent restriction of parasite growth. Together, these data establish that LRG-47 can influence pathogen control by simultaneously regulating macrophage-microbicidal activity and hemopoietic function.

Msp40 effector of root-knot nematode manipulates plant immunity to facilitate parasitism.

PubMed

Niu, Junhai; Liu, Pei; Liu, Qian; Chen, Changlong; Guo, Quanxin; Yin, Junmei; Yang, Guangsui; Jian, Heng

2016-01-22

Root-knot nematodes (RKNs) are obligate biotrophic parasites that invade plant roots and engage in prolonged and intimate relationships with their hosts. Nematode secretions, some of which have immunosuppressing activity, play essential roles in successful parasitism; however, their mechanisms of action remain largely unknown. Here, we show that the RKN-specific gene MiMsp40, cloned from Meloidogyne incognita, is expressed exclusively in subventral oesophageal gland cells and is strongly upregulated during early parasitic stages. Arabidopsis plants overexpressing MiMsp40 were more susceptible to nematode infection than were wild type plants. Conversely, the host-derived MiMsp40 RNAi suppressed nematode parasitism and/or reproduction. Moreover, overexpression of MiMsp40 in plants suppressed the deposition of callose and the expression of marker genes for bacterial elicitor elf18-triggered immunity. Transient expression of MiMsp40 prevented Bax-triggered defence-related programmed cell death. Co-agroinfiltration assays indicated that MiMsp40 also suppressed macroscopic cell death triggered by MAPK cascades or by the ETI cognate elicitors R3a/Avr3a. Together, these results demonstrate that MiMsp40 is a novel Meloidogyne-specific effector that is injected into plant cells by early parasitic stages of the nematode and that plays a role in suppressing PTI and/or ETI signals to facilitate RKN parasitism.

The relative contribution of climate variability and vector control coverage to changes in malaria parasite prevalence in Zambia 2006-2012.

PubMed

Bennett, Adam; Yukich, Josh; Miller, John M; Keating, Joseph; Moonga, Hawela; Hamainza, Busiku; Kamuliwo, Mulakwa; Andrade-Pacheco, Ricardo; Vounatsou, Penelope; Steketee, Richard W; Eisele, Thomas P

2016-08-05

Four malaria indicator surveys (MIS) were conducted in Zambia between 2006 and 2012 to evaluate malaria control scale-up. Nationally, coverage of insecticide-treated nets (ITNs) and indoor residual spraying (IRS) increased over this period, while parasite prevalence in children 1-59 months decreased dramatically between 2006 and 2008, but then increased from 2008 to 2010. We assessed the relative effects of vector control coverage and climate variability on malaria parasite prevalence over this period. Nationally-representative MISs were conducted in April-June of 2006, 2008, 2010 and 2012 to collect household-level information on malaria control interventions such as IRS, ITN ownership and use, and child parasite prevalence by microscopic examination of blood smears. We fitted Bayesian geostatistical models to assess the association between IRS and ITN coverage and climate variability and malaria parasite prevalence. We created predictions of the spatial distribution of malaria prevalence at each time point and compared results of varying IRS, ITN, and climate inputs to assess their relative contributions to changes in prevalence. Nationally, the proportion of households owning an ITN increased from 37.8 % in 2006 to 64.3 % in 2010 and 68.1 % in 2012, with substantial heterogeneity sub-nationally. The population-adjusted predicted child malaria parasite prevalence decreased from 19.6 % in 2006 to 10.4 % in 2008, but rose to 15.3 % in 2010 and 13.5 % in 2012. We estimated that the majority of this prevalence increase at the national level between 2008 and 2010 was due to climate effects on transmission, although there was substantial heterogeneity at the provincial level in the relative contribution of changing climate and ITN availability. We predict that if climate factors preceding the 2010 survey were the same as in 2008, the population-adjusted prevalence would have fallen to 9.9 % nationally. These results suggest that a combination of climate factors and reduced intervention coverage in parts of the country contributed to both the reduction and rebound in malaria parasite prevalence. Unusual rainfall patterns, perhaps related to moderate El Niño conditions, may have contributed to this variation. Zambia has demonstrated considerable success in scaling up vector control. This analysis highlights the importance of accounting for climate variability when using cross-sectional data for evaluation of malaria control efforts.

Disease-protective symbiosis among fishes and other aquatic animals

USGS Publications Warehouse

Snieszko, S.F.

1962-01-01

There have been numerous observations of one species of animal removing parasites from another. These are, however, generally regarded as biological curiosities rather than as significant factors in the control of parasites or disease.

The effects of parasite age and intensity on variability in acanthocephalan-induced behavioural manipulation.

PubMed

Franceschi, Nathalie; Bauer, Alexandre; Bollache, Loïc; Rigaud, Thierry

2008-08-01

Numerous parasites with complex life cycles are able to manipulate the behaviour of their intermediate host in a way that increases their trophic transmission to the definitive host. Pomphorhynchus laevis, an acanthocephalan parasite, is known to reverse the phototactic behaviour of its amphipod intermediate host, Gammarus pulex, leading to an increased predation by fish hosts. However, levels of behavioural manipulation exhibited by naturally-infected gammarids are extremely variable, with some individuals being strongly manipulated whilst others are almost not affected by infection. To investigate parasite age and parasite intensity as potential sources of this variation, we carried out controlled experimental infections on gammarids using parasites from two different populations. We first determined that parasite intensity increased with exposure dose, but found no relationship between infection and host mortality. Repeated measures confirmed that the parasite alters host behaviour only when it reaches the cystacanth stage which is infective for the definitive host. They also revealed, we believe for the first time, that the older the cystacanth, the more it manipulates its host. The age of the parasite is therefore a major source of variation in parasite manipulation. The number of parasites within a host was also a source of variation. Manipulation was higher in hosts infected by two parasites than in singly infected ones, but above this intensity, manipulation did not increase. Since the development time of the parasite was also different according to parasite intensity (it was longer in doubly infected hosts than in singly infected ones, but did not increase more in multi-infected hosts), individual parasite fitness could depend on the compromise between development time and manipulation efficiency. Finally, the two parasite populations tested induced slightly different degrees of behavioural manipulation.

The scaling of total parasite biomass with host body mass.

PubMed

Poulin, Robert; George-Nascimento, Mario

2007-03-01

The selective pressure exerted by parasites on their hosts will to a large extent be influenced by the abundance or biomass of parasites supported by the hosts. Predicting how much parasite biomass can be supported by host individuals or populations should be straightforward: ultimately, parasite biomass must be controlled by resource supply, which is a direct function of host metabolism. Using comparative data sets on the biomass of metazoan parasites in vertebrate hosts, we determined how parasite biomass scales with host body mass. If the rate at which host resources are converted into parasite biomass is the same as that at which host resources are channelled toward host growth, then on a log-log plot parasite biomass should increase with host mass with a slope of 0.75 when corrected for operating temperature. Average parasite biomass per host scaled with host body mass at a lower rate than expected (across 131 vertebrate species, slope=0.54); this was true independently of phylogenetic influences and also within the major vertebrate groups separately. Since most host individuals in a population harbour a parasite load well below that allowed by their metabolic rate, because of the stochastic nature of infection, it is maximum parasite biomass, and not average biomass, that is predicted to scale with metabolic rate among host species. We found that maximum parasite biomass scaled isometrically (i.e., slope=1) with host body mass. Thus, larger host species can potentially support the same parasite biomass per gram of host tissues as small host species. The relationship found between maximum parasite biomass and host body mass, with its slope greater than 0.75, suggests that parasites are not like host tissues: they are able to appropriate more host resources than expected from metabolically derived host growth rates.

[SWOT Analysis of the National Survey on Current Status of Major Human Parasitic Diseases in China].

PubMed

ZHU, Hui-hui; ZHOU, Chang-hai; CHEN, Ying-dan; ZANG, Wei; XIAO, Ning; ZHOU, Xiao-nong

2015-10-01

The National Survey on Current Status of Major Human Parasitic Diseases in China has been carried out since 2014 under the organization of the National Health and Family Planning Commission of the People's Republic of China. The National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (NIPD, China CDC) provided technical support and was responsible for quality control in this survey. This study used SWOT method to analyze the strengths, weaknesses, opportunities and threats that were encountered by he NIPD, China CDC during the completion of the survey. Accordingly, working strategies were proposed to facilitate the future field work.

Host genotype by parasite genotype interactions underlying the resistance of anopheline mosquitoes to Plasmodium falciparum.

PubMed

Lambrechts, Louis; Halbert, Jean; Durand, Patrick; Gouagna, Louis C; Koella, Jacob C

2005-01-11

Most studies on the resistance of mosquitoes to their malaria parasites focus on the response of a mosquito line or colony against a single parasite genotype. In natural situations, however, it may be expected that mosquito-malaria relationships are based, as are many other host-parasite systems, on host genotype by parasite genotype interactions. In such systems, certain hosts are resistant to one subset of the parasite's genotypes, while other hosts are resistant to a different subset. To test for genotype by genotype interactions between malaria parasites and their anopheline vectors, different genetic backgrounds (families consisting of the F1 offspring of individual females) of the major African vector Anopheles gambiae were challenged with several isolates of the human malaria parasite Plasmodium falciparum (obtained from naturally infected children in Kenya). Averaged across all parasites, the proportion of infected mosquitoes and the number of oocysts found in their midguts were similar in all mosquito families. Both indices of resistance, however, differed considerably among isolates of the parasite. In particular, no mosquito family was most resistant to all parasites, and no parasite isolate was most infectious to all mosquitoes. These results suggest that the level of mosquito resistance depends on the interaction between its own and the parasite's genotype. This finding thus emphasizes the need to take into account the range of genetic diversity exhibited by mosquito and malaria field populations in ideas and studies concerning the control of malaria.

Productivity and fishing pressure drive variability in fish parasite assemblages of the Line Islands, equatorial Pacific.

PubMed

Wood, Chelsea L; Baum, Julia K; Reddy, Sheila M W; Trebilco, Rowan; Sandin, Stuart A; Zgliczynski, Brian J; Briggs, Amy A; Micheli, Fiorenza

2015-05-01

Variability in primary productivity and fishing pressure can shape the abundance, species composition, and diversity of marine life. Though parasites comprise nearly half of marine species, their responses to these important forces remain little explored. We quantified parasite assemblages at two spatial scales, across a gradient in productivity and fishing pressure that spans six coral islands of the Line Islands archipelago and within the largest Line Island, Kiritimati, which experiences a west-to-east gradient in fishing pressure and upwelling-driven productivity. In the across-islands data set, we found that increasing productivity was correlated with increased parasite abundance overall, but that the effects of productivity differed among parasite groups. Trophically transmitted parasites increased in abundance with increasing productivity, but directly transmitted parasites did not exhibit significant changes. This probably arises because productivity has stronger effects on the abundance of the planktonic crustaceans and herbivorous snails that serve as the intermediate hosts of trophically transmitted parasites than on the higher-trophic level fishes that are the sole hosts of directly transmitted parasites. We also found that specialist parasites increased in response to increasing productivity, while generalists did not, possibly because specialist parasites tend to be more strongly limited by host availability than are generalist parasites. After the effect of productivity was controlled for, fishing was correlated with decreases in the abundance of trophically transmitted parasites, while directly transmitted parasites appeared to track host density; we observed increases in the abundance of parasites using hosts that experienced fishing-driven compensatory increases in abundance. The within-island data set confirmed these patterns for the combined effects of productivity and fishing on parasite abundance, suggesting that our conclusions are robust across a span of spatial scales. Overall, these results indicate that there are strong and variable effects of anthropogenic and natural drivers on parasite abundance and taxonomic richness. These effects are likely to be mediated by parasite traits, particularly by parasite transmission strategies.

RNA mobility in parasitic plant - host interactions.

PubMed

Westwood, James H; Kim, Gunjune

2017-04-03

The parasitic plant Cuscuta exchanges mRNAs with its hosts. Systemic mobility of mRNAs within plants is well documented, and has gained increasing attention as studies using grafted plant systems have revealed new aspects of mobile mRNA regulation and function. But parasitic plants take this phenomenon to a new level by forming seamless connections to a wide range of host species, and raising questions about how mRNAs might function after transfer to a different species. Cuscuta and other parasitic plant species also take siRNAs from their hosts, indicating that multiple types of RNA are capable of trans-specific movement. Parasitic plants are intriguing systems for studying RNA mobility, in part because such exchange opens new possibilities for control of parasitic weeds, but also because they provide a fresh perspective into understanding roles of RNAs in inter-organismal communication.

[Parasites of zoonotic importance in dog feces collected in parks and public squares of the city of Los Angeles, Bío-Bío, Chile].

PubMed

Luzio, Álvaro; Belmar, Pablo; Troncoso, Ignacio; Luzio, Patricia; Jara, Alexis; Fernández, Ítalo

2015-08-01

The contamination of public squares and parks with dog feces poses a risk to the population, since it may contain parasitic elements of zoonotic importance. To identify human pathogenic parasites in samples of dog feces collected from parks and public squares. 452 fecal dog samples collected from 65 squares and public parks were analyzed using the technique of Burrows. 60% (39/65) of the samples contained some parasitic forms with a zoonotic potential. Parasitic taxa with zoonotic risk were Toxocara sp., Ancylostoma sp., Dipylidium caninum, Giardia sp., Taenia sp., Toxascaris sp., Strongyloides sp., and Uncinaria sp. The detected parasites present a risk to human health, so it seems necessary to implement health education activities in the community, develop deworming plans, and control the canine overpopulation.

Gastrointestinal nematode species diversity in Soay sheep kept in a natural environment without active parasite control.

PubMed

Sinclair, Rona; Melville, Lynsey; Sargison, Fiona; Kenyon, Fiona; Nussey, Dan; Watt, Kathryn; Sargison, Neil

2016-08-30

Molecular methods based on ITS2 sequence analysis were used to identify strongylid parasites and describe their diversity in a management intervention and anthelmintic drug treatment-free sheep flock. Fourteen different nematode parasite species were identified in the flock and the results showed a greater level of nematode species diversity than is normally reported in managed farmed flocks, with the presence of parasites such as Bunostomum trigonocephalum, Ostertagia leptospicularis, Spiculopteragia houdemeri and Trichostrongylus retortaeformis that are considered to be absent or rare in sheep kept in comparable localities. The implied prevalences of Haemonchus contortus in lambs, and of Trichostrongylus axei in lambs, ewes and rams, were higher than those in farmed sheep kept in similar regions, while those of Teladorsagia circumcincta and Trichostrongylus vitrinus were lower. Comparison of the patterns of nematode parasite infection between the summer and autumn sampling periods showed differences from the scenarios that are commonplace in comparable managed flocks; with T. vitrinus burdens of the lambs being higher in the summer than in the winter, and Oesophagostomum venulosum being the predominant nematode species in the adult sheep during the summer, while more-or-less absent from these groups during the winter. Rams played an important role in the epidemiology of certain parasitic nematode species. The relatively non-pathogenic O. venulosum was the only parasitic nematode species to predominate in any group during the study. This preliminary characterisation of the nematode parasite burdens of sheep extensively grazed on diverse unimproved pastures will aid in the understanding of the parasitological consequences of intensive grazing management and of the manner in which modern agriculture upsets the equilibrium between parasites and their hosts. These factors must be accounted for when defining the concept of sustainable parasite control and informing sustainability with reference to commercially efficient sheep farming. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

Prevalence of intestinal parasitic infections among highland and lowland dwellers in Gamo area, South Ethiopia.

PubMed

Wegayehu, Teklu; Tsalla, Tsegaye; Seifu, Belete; Teklu, Takele

2013-02-18

Epidemiological information on the prevalence of intestinal parasitic infections in different regions is a prerequisite to develop appropriate control strategies. Therefore, this present study was conducted to assess the magnitude and pattern of intestinal parasitism in highland and lowland dwellers in Gamo area, South Ethiopia. Community-based cross-sectional study was conducted between September 2010 and July 2011 at Lante, Kolla Shelle, Dorze and Geressie kebeles of Gamo Gofa Zone, South Ethiopia. The study sites and study participants were selected using multistage sampling method. Data were gathered through house-to-house survey. A total of 858 stool specimens were collected and processed using direct wet mount and formol-ether concentration techniques for the presence of parasite. Out of the total examined subjects, 342(39.9%) were found positive for at least one intestinal parasite. The prevalence of Entamoeba histolytica/dispar was the highest 98(11.4%), followed by Giardia lamblia 91(10.6%), Ascaris lumbricoides 67(7.8%), Strongyloides stercoralis 51(5.9%), hookworm 42(4.9%), Trichuris trichiura 24(2.8%), Taenia species 18(2.1%), Hymenolepis nana 7(0.6%) and Schistosoma mansoni 1(0.12%). No statistically significant difference was observed in the prevalence of intestinal parasitic infections among lowland (37.9%) and highland dwellers (42.3%) (P = 0.185). The prevalence of intestinal parasitic infection was not significantly different among the study sites but it was relatively higher in Geressie (42.8%) than other kebeles. Sex was not associated with parasitic infections (P = 0.481). No statistically significant difference of infection was observed among the age groups (P = 0.228) but it was higher in reproductive age group. The high prevalence of intestinal parasitic infections among the lowland and highland dwellers in Gamo area indicated that parasitic infections are important public health problems. Thus, infection control measures and the development of awareness strategies to improve sanitation and health education should be considered.

Intestinal Parasitic Infections in HIV Infected and Non-Infected Patients in a Low HIV Prevalence Region, West-Cameroon

PubMed Central

Nkenfou, Céline Nguefeu; Nana, Christelle Tafou; Payne, Vincent Khan

2013-01-01

The magnitude of intestinal parasitic infection in acquired immunodeficiency syndrome patients requires careful consideration in the developing world where poor nutrition is associated with poor hygiene and several tropical diseases. However, there have been very few studies addressing this issue in Cameroon. This study was conducted to determine the prevalence of intestinal parasitosis in HIV/AIDS patients in Dschang -Cameroon. Stool and blood specimens from HIV/AIDS patients and control group were screened respectively for intestinal parasites and for HIV antibodies. Intestinal parasites were identified using direct microscopy, formalin-ether concentration and Ziehl Neelsen methods. Out of 396 participants recruited among patients consulting at hospital, 42 (10.6%) were HIV positive, thirty of them treatment naïve. The overall prevalence of intestinal parasites was 14.64%. Out of 42 HIV/AIDS patients, 59.5% (25/42) were infected with intestinal parasites, while only 9.32% (33/354) of the HIV negative patients were infected with intestinal parasites. The parasites detected in our study population included Crystosporidium parvum (2.53%), Entamoeba histolytica (7.52%), Entamoeba coli (4.04%), Giardia lamblia (0.25%), Trichuris trichura (0.25%), Strongyloides stercoralis (0.25%) and Taenia spp. (0.25%). In the HIV infected group, Crystosporidium parvum (19.04%), Entamoeba histolytica (19.04%), Entamoeba coli (21.42%), Giardia lamblia (2.38%), Strongyloides stercoralis (0.25%) and Taenia spp. (0.25%) were found. Crystosporidium parvum was found to be significantly higher in HIV/AIDS patients than in controls (P<0.05). Multivariate analysis showed that the HIV status and the quality of water were the major risk factors for intestinal parasitosis. Routine examinations of stool samples for parasites would significantly benefit the HIV patients by contributing in reducing morbidity and improving the efficiency of antiretroviral treatment. Even after the introduction of free anti-retroviral drugs, opportunistic intestinal infections are still a threat. HIV patients should be screened routinely for intestinal parasites and treated for their overall well being. PMID:23451283

Effects of Intra- and Interpatch Host Density on Egg Parasitism by Three Species of Trichogramma

PubMed Central

Grieshop, Matthew J.; Flinn, Paul W.; Nechols, James R.

2010-01-01

Host-foraging responses to different intra- and interpatch densities were used to assess three Trichogramma spp. (Hymenoptera: Trichogrammatidae) Trichogramma deion Pinto and Oatman, T. ostriniae Pang and Chen, and T. pretiosum Riley — as potential biological control agents for the Indian meal moth, Plodia interpunctella Hübner (Lepidoptera: Pyralidae). Single naïve females were allowed 6 h to forage in Plexiglas arenas with four different spatial arrangements of host eggs, nine single-egg patches), nine four-egg patches, 36 single-egg patches, and 36 four-egg patches. No significant differences were found among species in the number of patches parasitized. As expected, all three species parasitized the most eggs in the 36 four-egg patch treatment and the least in the nine single-egg patch treatment. T. deion parasitized significantly more eggs than T. pretiosum on the nine four-egg patches. T. ostriniae parasitized significantly more patches when intrapatch density was greater, regardless of interpatch density. In contrast, T. deion only parasitized more patches at the greater intrapatch density when the interpatch density was low. Patch density had no effect on T. pretiosum. The spatial pattern of parasitism was more aggregated for T. deion and T. ostriniae in the 36 four-egg patches treatment compared to the 36 single-egg patches treatment. Therefore, intrapatch density was more important than interpatch density for T. ostriniae, and potentially for T. deion, but not for T. pretiosum. T. deion may be the best candidate for augmentative biological control because it parasitized either slightly or significantly more eggs than the other two species in all four treatments. Furthermore, the pattern of parasitism by T. deion in the 36 four-egg patches treatment was the most aggregated among the three species, suggesting a more thorough searching pattern. In contrast, T. pretiosum had the least aggregated pattern of parasitism and therefore may have used a more random foraging pattern. PMID:20673123

Effects of intra- and interpatch host density on egg parasitism by three species of Trichogramma.

PubMed

Grieshop, Matthew J; Flinn, Paul W; Nechols, James R

2010-01-01

Host-foraging responses to different intra- and interpatch densities were used to assess three Trichogramma spp. (Hymenoptera: Trichogrammatidae) Trichogramma deion Pinto and Oatman, T. ostriniae Pang and Chen, and T. pretiosum Riley - as potential biological control agents for the Indian meal moth, Plodia interpunctella Hübner (Lepidoptera: Pyralidae). Single naïve females were allowed 6 h to forage in Plexiglas arenas with four different spatial arrangements of host eggs, nine single-egg patches), nine four-egg patches, 36 single-egg patches, and 36 four-egg patches. No significant differences were found among species in the number of patches parasitized. As expected, all three species parasitized the most eggs in the 36 four-egg patch treatment and the least in the nine single-egg patch treatment. T. deion parasitized significantly more eggs than T. pretiosum on the nine four-egg patches. T. ostriniae parasitized significantly more patches when intrapatch density was greater, regardless of interpatch density. In contrast, T. deion only parasitized more patches at the greater intrapatch density when the interpatch density was low. Patch density had no effect on T. pretiosum. The spatial pattern of parasitism was more aggregated for T. deion and T. ostriniae in the 36 four-egg patches treatment compared to the 36 single-egg patches treatment. Therefore, intrapatch density was more important than interpatch density for T. ostriniae, and potentially for T. deion, but not for T. pretiosum. T. deion may be the best candidate for augmentative biological control because it parasitized either slightly or significantly more eggs than the other two species in all four treatments. Furthermore, the pattern of parasitism by T. deion in the 36 four-egg patches treatment was the most aggregated among the three species, suggesting a more thorough searching pattern. In contrast, T. pretiosum had the least aggregated pattern of parasitism and therefore may have used a more random foraging pattern.

An attempt to replace an ivermectin-resistant Cooperia spp. population by a susceptible one on grazing pastures based on epidemiological principles and refugia management.

PubMed

Fiel, C A; Steffan, P E; Muchiut, S M; Fernández, A S; Bernat, G; Riva, E; Lloberas, M M; Almada, A; Homer, D

2017-11-15

The maintenance of anthelmintic-susceptible parasite refugia to delay the onset of anthelmintic resistance is an almost impossible effort in many grazing livestock production countries given that current refugia consist of already resistant parasites. Rather, efforts could be focused on replacing the resistant parasite refugia by susceptible parasite ones and implementing sustainable parasite control measures from then on. To this purpose, a trial was conducted to attempt to establish a new population of ivermectin-susceptible Cooperia sp. on a beef cattle farm with proven problems of ivermectin-resistant Cooperia. During two consecutive years, 82 (Year 1) and 100 (Year 2) recently weaned and parasite-free heifers were inoculated with 40,000 or 30,000 susceptible Cooperia L3, respectively, at a time when levels of resistant parasite refugia were normally low. The animals were subsequently allowed to graze on the problem pastures during autumn until the end of spring. Levels of parasitism in the animals and on pasture were monitored monthly and animals were treated with levamisole when needed. The combination of parasitological monitoring and local epidemiological knowledge was essential to determine when treatments were to be administered. No clinical signs of gastrointestinal parasitosis in the herd were observed throughout the study and unnecessary treatments were avoided. Faecal egg counts reduction tests (FECRT) and controlled efficacy tests (CET) employing worm counts were carried out at different times throughout the study to determine the clinical efficacy (FECRT) and the absolute efficacy (CET) of ivermectin, respectively. The clinical efficacy of ivermectin increased from an initial 73% to 99.4%, while the absolute efficacy increased from 54.1% to 87.5% after just two animal production cycles. The switch from a resistant parasite population to a susceptible one requires knowledge of parasitological epidemiology, especially in relation to seasonal variations of parasite populations in both the host and in refugia. Copyright © 2017 Elsevier B.V. All rights reserved.

Parasitic infections associated with malignancy and leprosy.

PubMed

Azab, M E; Mohamed, N H; Salem, S A; Safar, E H; Bebars, M A; Sabry, N M; Mohamed, M S

1992-04-01

Results of parasitic infections, as revealed by urine and stool examination was significant (P less than 0.05) in 43.3% of patients suffering from different malignant diseases and non significant (P greater than 0.05) in 29.3% of leprosy patients compared to 22% in control subjects. The most prevalent parasites were E. histolytica and G. lamblia. Cryptosporidium occysts were not detected. By stool examination and culture, S. stercoralis larvae were detected only in the malignancy group. The most common parasites occurring concomitantly were A. duodenale and S. stercoralis. By the IFAT, strongyloidiasis gave significantly higher positive results in the malignancy group than in the leprosy and control groups. IFAT for toxocariasis, showed highly significant positivity in the leprosy group and significantly positivity in the malignancy group. For toxoplasmosis, it showed highly significant positive results in both leprosy and malignancy groups. Eosinophilia was significantly more prominent among malignancy patients and insignificant among those with leprosy. Parasitic infection detected by urine and stool examination among patients with eosinophilia was found in 76% of the malignancy patients and in 66.7% of the leprosy patients.

Uncovering the transmission dynamics of Plasmodium vivax using population genetics

PubMed Central

Barry, Alyssa E.; Waltmann, Andreea; Koepfli, Cristian; Barnadas, Celine; Mueller, Ivo

2015-01-01

Population genetic analysis of malaria parasites has the power to reveal key insights into malaria epidemiology and transmission dynamics with the potential to deliver tools to support control and elimination efforts. Analyses of parasite genetic diversity have suggested that Plasmodium vivax populations are more genetically diverse and less structured than those of Plasmodium falciparum indicating that P. vivax may be a more ancient parasite of humans and/or less susceptible to population bottlenecks, as well as more efficient at disseminating its genes. These population genetic insights into P. vivax transmission dynamics provide an explanation for its relative resilience to control efforts. Here, we describe current knowledge on P. vivax population genetic structure, its relevance to understanding transmission patterns and relapse and how this information can inform malaria control and elimination programmes. PMID:25891915

Prevention and Control of Cryptosporidiosis

MedlinePlus

... Submit" /> Parasites Home Prevention & Control Recommend on Facebook Tweet Share Compartir Prevention & Control Topics Prevention & Control - General Public Prevention & Control - Immunocompromised ...

[Investigation of major parasitic diseases and related knowledge, attitude and practice among rural residents in Liyang City].

PubMed

Yan-Li, Guo; Yong-Gen, Zou; Yi-Qing, Xie; Hong, Chen; Ming-Zhen, He; Lai-Fu, Lü; Li-Zhong, Huang; Xiao-Lin, Jin

2017-09-27

To investigate the prevalence of major parasitic diseases and related knowledge, attitude and practice among rural residents in Liyang City, so as to provide the evidence for formulating appropriate preventive strategies and measures. Three villages were selected from three towns as survey sites, and the residents who were above three years old and had been in the village for over six months were investigated. The Kato-Katz technique was applied to detect intestinal parasite eggs in residents' feces, and the cellophane anal swab was used to detect Enterobius vermicularis eggs among children aged 3-6 years. The iodine liquid smear and saline smear methods were used to examine intestinal protozoa cysts or trophozoites. Hookworm species were identified by the tube filter paper culture method. A structured questionnaire was used to collect the information on residents' knowledge, attitude and practice of the prevention and control of major parasitic diseases. Totally 759 residents were investigated and tested at the three rural survey sites, and only 2 cases were detected of parasitic infection and the total infection rate was 0.26%. Both cases were mild infections without mixed infection. The total awareness rate of knowledge on ascariasis, trichuriasis and ancylostomiasis was 37.9%, while the awareness rate of knowledge on clonorchiasis was 13.8%. The age and educational level were important factors of the knowledge on prevention and control of parasitic diseases among the residents. The formation rates of washing hands before meal and after using the toilet, and never drinking unboiled water were 83.8% and 92.1%, respectively. Totally 11.6% of the residents usually ate raw or half-cooked freshwater fishes and shrimps, and 53.0% had not the behavior to prepare raw and cooked food using the different chopping boards. The proportions of residents using fresh feces as manure and working in the field with bare feet were 13.8% and 22.8% respectively. The proportions of residents who thought they could, could not, or were not sure to change the risk behaviors and habits of parasitic infections were 40.2%, 28.5% and 31.4%, respectively. The infection rate of major parasitic diseases among the rural residents in Liyang City is low, and the awareness rate of knowledge on preventing parasitic diseases is also low. Therefore, the health education on the prevention and control of parasitic diseases should be strengthened to guide them to develop good hygiene, diet and farming habits. The environmental sanitation should be continuously improved to block the endemic of parasitic infection.

To Live Like a Pig and Die Like a Dog: Environmental Implications for World War I in East Africa

DTIC Science & Technology

2009-12-03

held decisive advantages including greater numbers of troops, more robust logistics, and unchallenged control of the sea lines of communications...The Center for Disease Control defines malaria as “a serious and sometimes fatal disease caused by a parasite that commonly infects a certain type of...malaria parasites that can infect humans, Plasmodium falciparum remains indigenous to east 32 Center for Disease Control, “Malaria Home > Frequently

Rapid identification of genes controlling virulence and immunity in malaria parasites

PubMed Central

Xangsayarath, Phonepadith; Tang, Jianxia; Yahata, Kazuhide; Zoungrana, Augustin; Mitaka, Hayato; Acharjee, Arita; Datta, Partha P.; Hunt, Paul; Carter, Richard; Kaneko, Osamu; Mustonen, Ville; Pain, Arnab

2017-01-01

Identifying the genetic determinants of phenotypes that impact disease severity is of fundamental importance for the design of new interventions against malaria. Here we present a rapid genome-wide approach capable of identifying multiple genetic drivers of medically relevant phenotypes within malaria parasites via a single experiment at single gene or allele resolution. In a proof of principle study, we found that a previously undescribed single nucleotide polymorphism in the binding domain of the erythrocyte binding like protein (EBL) conferred a dramatic change in red blood cell invasion in mutant rodent malaria parasites Plasmodium yoelii. In the same experiment, we implicated merozoite surface protein 1 (MSP1) and other polymorphic proteins, as the major targets of strain-specific immunity. Using allelic replacement, we provide functional validation of the substitution in the EBL gene controlling the growth rate in the blood stages of the parasites. PMID:28704525

War on Two Fronts: The Fight against Parasites in Korea and Vietnam.

PubMed

Harrison, Mark; Yim, Sung Vin

2017-07-01

The Vietnam War has long been regarded as pivotal in the history of the Republic of Korea, although its involvement in this conflict remains controversial. While most scholarship has focused on the political and economic ramifications of the war - and allegations of brutality by Korean troops - few scholars have considered the impact of the conflict upon medicine and public health. This article argues that the war had a transformative impact on medical careers and public health in Korea, and that this can be most clearly seen in efforts to control parasitic diseases. These diseases were a major drain on military manpower and a matter of growing concern domestically. The deployment to Vietnam boosted research into parasitic diseases of all kinds and accelerated the domestic campaign to control malaria and intestinal parasites. It also had a formative impact upon the development of overseas aid.

War on Two Fronts: The Fight against Parasites in Korea and Vietnam

PubMed Central

Harrison, Mark; Yim, Sung Vin

2017-01-01

The Vietnam War has long been regarded as pivotal in the history of the Republic of Korea, although its involvement in this conflict remains controversial. While most scholarship has focused on the political and economic ramifications of the war – and allegations of brutality by Korean troops – few scholars have considered the impact of the conflict upon medicine and public health. This article argues that the war had a transformative impact on medical careers and public health in Korea, and that this can be most clearly seen in efforts to control parasitic diseases. These diseases were a major drain on military manpower and a matter of growing concern domestically. The deployment to Vietnam boosted research into parasitic diseases of all kinds and accelerated the domestic campaign to control malaria and intestinal parasites. It also had a formative impact upon the development of overseas aid. PMID:28604294

A conserved endocrine mechanism controls the formation of dauer and infective larvae in nematodes.

PubMed

Ogawa, Akira; Streit, Adrian; Antebi, Adam; Sommer, Ralf J

2009-01-13

Under harsh environmental conditions, Caenorhabditis elegans larvae undergo arrest and form dauer larvae that can attach to other animals to facilitate dispersal. It has been argued that this phenomenon, called phoresy, represents an intermediate step toward parasitism. Indeed, parasitic nematodes invade their hosts as infective larvae, a stage that shows striking morphological similarities to dauer larvae. Although the molecular regulation of dauer entry in C. elegans involves insulin and TGF-beta signaling, studies of TGF-beta orthologs in parasitic nematodes didn't provide evidence for a common origin of dauer and infective larvae. To identify conserved regulators between Caenorhabditis and parasitic nematodes, we used an evolutionary approach involving Pristionchus pacificus as an intermediate. We show by mutational and pharmacological analysis that Pristionchus and Caenorhabditis share the dafachronic acid-DAF-12 system as the core endocrine module for dauer formation. One dafachronic acid, Delta7-DA, has a conserved role in the mammalian parasite Strongyloides papillosus by controlling entry into the infective stage. Application of Delta7-DA blocks formation of infective larvae and results in free-living animals. Conservation of this small molecule ligand represents a fundamental link between dauer and infective larvae and might provide a general strategy for nematode parasitism.

Cessation of a salmon decline with control of parasites.

PubMed

Peacock, Stephanie J; Krkosek, Martin; Proboszcz, Stan; Orr, Craig; Lewis, Mark A

2013-04-01

The resilience of coastal social-ecological systems may depend on adaptive responses to aquaculture disease outbreaks that can threaten wild and farm fish. A nine-year study of parasitic sea lice (Lepeophtheirus salmonis) and pink salmon (Oncorhynchus gorbuscha) from Pacific Canada indicates that adaptive changes in parasite management on salmon farms have yielded positive conservation outcomes. After four years of sea lice epizootics and wild salmon population decline, parasiticide application on salmon farms was adapted to the timing of wild salmon migrations. Winter treatment of farm fish with parasiticides, prior to the out-migration of wild juvenile salmon, has reduced epizootics of wild salmon without significantly increasing the annual number of treatments. Levels of parasites on wild juvenile salmon significantly influence the growth rate of affected salmon populations, suggesting that these changes in management have had positive outcomes for wild salmon populations. These adaptive changes have not occurred through formal adaptive management, but rather, through multi-stakeholder processes arising from a contentious scientific and public debate. Despite the apparent success of parasite control on salmon farms in the study region, there remain concerns about the long-term sustainability of this approach because of the unknown ecological effects of parasticides and the potential for parasite resistance to chemical treatments.

[Survey and analysis of major human parasitic diseases in Chongqing City].

PubMed

Shan-Shan, Li; Fei, Luo; Jun, Xie; Yi, Yuan

2018-03-02

To investigate the epidemic of major human parasitic diseases in Chongqing City, so as to provide a reference for developing prevention and control strategies. According to the unified methods formulated by the national investigation scheme and stratified cluster random sampling, 36 rural pilots and 50 urban pilots were selected in Chongqing City. The number of the objects investigated in individual pilot was defined over 250. Totally 22 263 residents were detected. The overall infection rate of intestinal parasites was 5.41%. The infection rates of Ascaris lumbricoides , hookworm, Trichuris trichiura , and Enterobius vermicularis were 1.20%, 4.23%, 0.13% and 0.47% respectively. Only 0.22% of the infections were co-infections. The infection rate of overall intestinal parasites was statistically higher in the females than that in the males ( χ 2 = 15.19, P < 0.05), and the infection rates were significantly different among various age groups, occupations, education levels, and regions ( χ 2 = 15.19, 396.72, 421.07, 347.79, all P < 0.05). The infection rates of major human parasites in Chongqing show an obviously decreasing tendency compared with the rates of the past twice of national surveys. In the future, the controlling practices are obliged to focus on reducing the infection rates of soil-borne parasites.

Actin Filament Polymerization Regulates Gliding Motility by Apicomplexan ParasitesV⃞

PubMed Central

Wetzel, D.M.; Håkansson, S.; Hu, K.; Roos, D.; Sibley, L.D.

2003-01-01

Host cell entry by Toxoplasma gondii depends critically on actin filaments in the parasite, yet paradoxically, its actin is almost exclusively monomeric. In contrast to the absence of stable filaments in conventional samples, rapid-freeze electron microscopy revealed that actin filaments were formed beneath the plasma membrane of gliding parasites. To investigate the role of actin filaments in motility, we treated parasites with the filament-stabilizing drug jasplakinolide (JAS) and monitored the distribution of actin in live and fixed cells using yellow fluorescent protein (YFP)-actin. JAS treatment caused YFP-actin to redistribute to the apical and posterior ends, where filaments formed a spiral pattern subtending the plasma membrane. Although previous studies have suggested that JAS induces rigor, videomicroscopy demonstrated that JAS treatment increased the rate of parasite gliding by approximately threefold, indicating that filaments are rate limiting for motility. However, JAS also frequently reversed the normal direction of motility, disrupting forward migration and cell entry. Consistent with this alteration, subcortical filaments in JAS-treated parasites occurred in tangled plaques as opposed to the straight, roughly parallel orientation observed in control cells. These studies reveal that precisely controlled polymerization of actin filaments imparts the correct timing, duration, and directionality of gliding motility in the Apicomplexa. PMID:12589042

Mycelial forms of Coccidioides spp. in the parasitic phase associated to pulmonary coccidioidomycosis with type 2 diabetes mellitus.

PubMed

Muñoz-Hernández, B; Martínez-Rivera, M A; Palma Cortés, G; Tapia-Díaz, A; Manjarrez Zavala, M E

2008-09-01

Pulmonary coccidioidomycosis shares characteristics with other pulmonary pathologies. In tissue, spherules containing endospores are markers of Coccidioides immitis and C. posadasii infection. Mycelial forms presenting without classical parasitic structures are often misdiagnosed. The study was performed at the National Institute of Respiratory Diseases (INER) of Mexico between September 1991 and June 2005 and analyzed the association between cases, controls, and risk factors, including co-morbidity. A case was defined as any patient who presented mycelial forms and a control as any patient who presented only spherules or no parasitic forms. All patients (n = 44) with pulmonary coccidioidomycosis were diagnosed by culture, histopathology, cytology, and immunology. Type 2 diabetic patients with pulmonary coccidioidomycosis were four times more likely than non-diabetics to develop parasitic mycelial forms (95% confidence interval [CI], 0.85-20.10; P < 0.01). We formulated a comprehensive definition based on the results as follows: patients with pulmonary coccidioidomycosis with an evolution longer than 8 months, cough, hemoptysis, radiological evidence of a cavitary lesion, and type 2 diabetes mellitus, develop parasitic mycelial forms of Coccidioides spp. Based on microscopic images of patient specimens, we propose incorporating mycelial forms into the parasitic phase of Coccidioides spp. in patients with type 2 diabetes mellitus and chronic and cavitary pulmonary coccidioidomycosis.

Acanthocephala Parasite (Profilicollis spp.) Loads in Correlation to Pacific Mole Crab (Emerita analoga) Size

NASA Astrophysics Data System (ADS)

Cheng, T.; Huang, S.; Galathe, M.; Jenkins, M.; Ramirez, A.; Crosby, L.; Barrera, J.; FitzHoward, S.

2013-12-01

Since 2002, San Francisco Bay students have been conducting marine ecosystem monitoring through a joint project with the Long-term Monitoring Program and Experiential Training for Students (LiMPETS), in conjunction with the Gulf of Farallones National Marine Sanctuary. Each year students collect population and demographic data on Pacific mole crabs (Emerita analoga), an indicator species that lives in the sandy beach habitat in temperate regions along the Pacific Ocean. Pacific mole crabs are filter feeding crustaceans that inhabit the intertidal swash zone and are known to be an intermediate host for parasitic ';spiny-headed' worms in the phylum Acanthocephala (Profilicollis spp.). Sampling takes place during their reproductive period, which occurs from spring to fall, and includes measuring total body length of the Pacific mole crabs and dissecting them to determine presence of Acanthocephalan parasites. We hypothesize that due to larger body mass, larger Pacific mole crabs will have a greater number of Acanthocephala parasites.We conducted several analyses using the LiMPETS long-term data. Specifically, we compared body length, crab gender, and parasite abundance from Pacific mole crabs sampled from four beaches located in the county and city of San Francisco. Our results indicated that larger Pacific mole crabs do not necessarily have more parasites, but are more likely to have at least one parasite, while female Pacific mole crabs carrying eggs, have more parasites than males or females without eggs. We also found that parasite loads per mole crab was highest in the spring. Further analysis will be conducted to determine factors affecting Pacific mole crab parasite loads. Studying Pacific mole crabs help evaluate the health of California's intertidal systems and how human activities, geologic changes, and climate changes all make huge impacts to the intertidal ecosystems.

Epidemiology and control of echinococcosis in central Asia, with particular reference to the People's Republic of China.

PubMed

Zhang, Wenbao; Zhang, Zhuangzhi; Wu, Weiping; Shi, Baoxin; Li, Jun; Zhou, Xiaonong; Wen, Hao; McManus, Donald P

2015-01-01

At least 270 million people (58% of the total population) are at risk of cystic echinococcosis (CE) in Central Asia including areas of Mongolia, Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, Uzbekistan, Afghanistan, Iran, Pakistan and western China. The annual surgical incidence rate in Uzbekistan and Tadjikistan has been estimated to be as high as 25-27 cases/100,000 with the highest prevalence reaching 10% (range from 0.8 to 11.9%) in some Tibetan communities in western China. Echinococcus transmission in the region is largely associated with social factors including limited community knowledge of echinococcosis, small-scale household animal production, home killing of livestock, and the feeding of dogs with uncooked offal. Alveolar echinococcosis (AE) is also endemic in Central Asia and is recognized as a major problem in some Tibetan communities with up to 6% of villagers infected in some villages. In western China, 5-30% of the population are seropositive against E. granulosus antigens, indicating that a large number of individuals have been exposed to the parasite. Although echinococcosis control programs have been initiated in some countries in Central Asia, control efforts are generally fragmented and uncoordinated. Monthly deworming of dogs with praziquantel (PZQ), as a key measure to control the Echinococcus parasites, has been used in western China. However, the approach has proven difficult in local semi-nomadic communities. Additional control measures including health education, domestic livestock animal treatment/vaccination and dog vaccination are needed in CE-endemic areas to accelerate progress. Copyright © 2014. Published by Elsevier B.V.

A De Novo-Assembly Based Data Analysis Pipeline for Plant Obligate Parasite Metatranscriptomic Studies.

PubMed

Guo, Li; Allen, Kelly S; Deiulio, Greg; Zhang, Yong; Madeiras, Angela M; Wick, Robert L; Ma, Li-Jun

2016-01-01

Current and emerging plant diseases caused by obligate parasitic microbes such as rusts, downy mildews, and powdery mildews threaten worldwide crop production and food safety. These obligate parasites are typically unculturable in the laboratory, posing technical challenges to characterize them at the genetic and genomic level. Here we have developed a data analysis pipeline integrating several bioinformatic software programs. This pipeline facilitates rapid gene discovery and expression analysis of a plant host and its obligate parasite simultaneously by next generation sequencing of mixed host and pathogen RNA (i.e., metatranscriptomics). We applied this pipeline to metatranscriptomic sequencing data of sweet basil (Ocimum basilicum) and its obligate downy mildew parasite Peronospora belbahrii, both lacking a sequenced genome. Even with a single data point, we were able to identify both candidate host defense genes and pathogen virulence genes that are highly expressed during infection. This demonstrates the power of this pipeline for identifying genes important in host-pathogen interactions without prior genomic information for either the plant host or the obligate biotrophic pathogen. The simplicity of this pipeline makes it accessible to researchers with limited computational skills and applicable to metatranscriptomic data analysis in a wide range of plant-obligate-parasite systems.

Parasites of pigs in two farms with poor husbandry practices in Bishoftu, Ethiopia.

PubMed

Jufare, Alemnesh; Awol, Nesibu; Tadesse, Fanos; Tsegaye, Yisehak; Hadush, Birhanu

2015-04-30

A cross-sectional study was conducted from November 2011 to April 2012 on a total of 384 pigs from two privately owned intensive farms in Bishoftu, Ethiopia. The objectives of the study were to identify and determine the prevalence of common parasites of pigs. For the determination of gastrointestinal (GIT) parasites, faecal samples were collected from the study animals and subjected to standard parasitological examination techniques. Physical examination was conducted for the presence of skin parasitic lesions and skin scrapings were collected to determine prevalence of ectoparasites. The overall prevalence of GIT parasites in the pigs was 25% (96/384). Examination of faecal samples revealed the ova or oocysts of four different gastrointestinal parasites, namely Coccidia (12%), Strongyles (5.2%), Ascaris suum (4.9%) and Trichuris suis (2.9%). Mixed infection by at least two parasite species was observed in 3.65% (14/384) of the pigs. The only ectoparasite species identified was Sarcoptes scabiei var. suis, with a prevalence of 2.6%. This study indicates that pig parasites are a major problem in the study area, hence implementation of strategic control measures and appropriate hygienic management systems are recommended to reduce the prevalence of parasites.

Population Genetics of Plasmodium vivax in Four Rural Communities in Central Vietnam

PubMed Central

Hong, Nguyen Van; Delgado-Ratto, Christopher; Thanh, Pham Vinh; Van den Eede, Peter; Guetens, Pieter; Binh, Nguyen Thi Huong; Phuc, Bui Quang; Duong, Tran Thanh; Van Geertruyden, Jean Pierre; D’Alessandro, Umberto; Erhart, Annette; Rosanas-Urgell, Anna

2016-01-01

Background The burden of malaria in Vietnam has drastically reduced, prompting the National Malaria Control Program to officially engage in elimination efforts. Plasmodium vivax is becoming increasingly prevalent, remaining a major problem in the country's central and southern provinces. A better understanding of P. vivax genetic diversity and structure of local parasite populations will provide baseline data for the evaluation and improvement of current efforts for control and elimination. The aim of this study was to examine the population genetics and structure of P. vivax isolates from four communities in Tra Leng commune, Nam Tra My district in Quang Nam, Central Vietnam. Methodology/Principal Findings P. vivax mono infections collected from 234 individuals between April 2009 and December 2010 were successfully analyzed using a panel of 14 microsatellite markers. Isolates displayed moderate genetic diversity (He = 0.68), with no significant differences between study communities. Polyclonal infections were frequent (71.4%) with a mean multiplicity of infection of 1.91 isolates/person. Low but significant genetic differentiation (FST value from -0.05 to 0.18) was observed between the community across the river and the other communities. Strong linkage disequilibrium (IAS = 0.113, p < 0.001) was detected across all communities, suggesting gene flow within and among them. Using multiple approaches, 101 haplotypes were grouped into two genetic clusters, while 60.4% of haplotypes were admixed. Conclusions/Significance In this area of Central Vietnam, where malaria transmission has decreased significantly over the past decade, there was moderate genetic diversity and high occurrence of polyclonal infections. Local human populations have frequent social and economic interactions that facilitate gene flow and inbreeding among parasite populations, while decreasing population structure. Findings provide important information on parasites populations circulating in the study area and are relevant to current malaria elimination efforts. PMID:26872387

The sight of an adult brood parasite near the nest is an insufficient cue for a honeyguide host to reject foreign eggs.

PubMed

Tong, Wenfei; Horrocks, Nicholas P C; Spottiswoode, Claire N

2015-07-01

Hosts of brood-parasitic birds typically evolve anti-parasitism defences, including mobbing of parasitic intruders at the nest and the ability to recognize and reject foreign eggs from their clutches. The Greater Honeyguide Indicator indicator is a virulent brood parasite that punctures host eggs and kills host young, and accordingly, a common host, the Little Bee-eater Merops pusillus frequently rejects entire clutches that have been parasitized. We predicted that given the high costs of accidentally rejecting an entire clutch, and that the experimental addition of a foreign egg is insufficient to induce this defence, Bee-eaters require the sight of an adult parasite near the nest as an additional cue for parasitism before they reject a clutch. We found that many Little Bee-eater parents mobbed Greater Honeyguide dummies while ignoring barbet control dummies, showing that they recognized them as a threat. Surprisingly, however, neither a dummy Honeyguide nor the presence of a foreign egg, either separately or in combination, was sufficient to stimulate egg rejection.

The sight of an adult brood parasite near the nest is an insufficient cue for a honeyguide host to reject foreign eggs

PubMed Central

Tong, Wenfei; Horrocks, Nicholas P C; Spottiswoode, Claire N

2015-01-01

Hosts of brood-parasitic birds typically evolve anti-parasitism defences, including mobbing of parasitic intruders at the nest and the ability to recognize and reject foreign eggs from their clutches. The Greater Honeyguide Indicator indicator is a virulent brood parasite that punctures host eggs and kills host young, and accordingly, a common host, the Little Bee-eater Merops pusillus frequently rejects entire clutches that have been parasitized. We predicted that given the high costs of accidentally rejecting an entire clutch, and that the experimental addition of a foreign egg is insufficient to induce this defence, Bee-eaters require the sight of an adult parasite near the nest as an additional cue for parasitism before they reject a clutch. We found that many Little Bee-eater parents mobbed Greater Honeyguide dummies while ignoring barbet control dummies, showing that they recognized them as a threat. Surprisingly, however, neither a dummy Honeyguide nor the presence of a foreign egg, either separately or in combination, was sufficient to stimulate egg rejection. PMID:26300559

Diseases and parasites of the sea lamprey, Petromyzon marinus, in the Lake Huron basin

USGS Publications Warehouse

McLain, Alberton L.

1952-01-01

Sea lampreys from the Lake Huron basin carried no external parasites and showed a fairly low degree of infection by internal parasites. The material examined represented three life-history stages of the sea lamprey. Recently transformed downstream migrants (215 specimens) harbored only nematodes belonging to the genus Camallanus. The percentage of infection was 2.3. Active feeders from the lake (29 lampreys) revealed the highest degree of parasitism (31.0 percent) with the following parasites present: Echinorhynchus coregoni Linkins; Triaenophorus crassus Forel; and Camallanus sp. Among the 257 sexually mature upstream migrants (14.8 percent infected) Echinorhynchus coregoni and E. leidyi Van Cleave were the most common. Only occasional nematodes and cestodes were found, which fact indicates a failure of the lamprey to carry these parasites to the end of its natural life. Of the parasites observed, only the nematodes gave evidence of serious damage to the host. The study suggests that the role played by parasites in the natural control of the sea lamprey in its new habitat in the upper Great Lakes is of minor importance.

Cardiac Involvement with Parasitic Infections

PubMed Central

Hidron, Alicia; Vogenthaler, Nicholas; Santos-Preciado, José I.; Rodriguez-Morales, Alfonso J.; Franco-Paredes, Carlos; Rassi, Anis

2010-01-01

Summary: Parasitic infections previously seen only in developing tropical settings can be currently diagnosed worldwide due to travel and population migration. Some parasites may directly or indirectly affect various anatomical structures of the heart, with infections manifested as myocarditis, pericarditis, pancarditis, or pulmonary hypertension. Thus, it has become quite relevant for clinicians in developed settings to consider parasitic infections in the differential diagnosis of myocardial and pericardial disease anywhere around the globe. Chagas' disease is by far the most important parasitic infection of the heart and one that it is currently considered a global parasitic infection due to the growing migration of populations from areas where these infections are highly endemic to settings where they are not endemic. Current advances in the treatment of African trypanosomiasis offer hope to prevent not only the neurological complications but also the frequently identified cardiac manifestations of this life-threatening parasitic infection. The lack of effective vaccines, optimal chemoprophylaxis, or evidence-based pharmacological therapies to control many of the parasitic diseases of the heart, in particular Chagas' disease, makes this disease one of the most important public health challenges of our time. PMID:20375355

Helminth parasites alter protection against Plasmodium infection.

PubMed

Salazar-Castañon, Víctor H; Legorreta-Herrera, Martha; Rodriguez-Sosa, Miriam

2014-01-01

More than one-third of the world's population is infected with one or more helminthic parasites. Helminth infections are prevalent throughout tropical and subtropical regions where malaria pathogens are transmitted. Malaria is the most widespread and deadliest parasitic disease. The severity of the disease is strongly related to parasite density and the host's immune responses. Furthermore, coinfections between both parasites occur frequently. However, little is known regarding how concomitant infection with helminths and Plasmodium affects the host's immune response. Helminthic infections are frequently massive, chronic, and strong inductors of a Th2-type response. This implies that infection by such parasites could alter the host's susceptibility to subsequent infections by Plasmodium. There are a number of reports on the interactions between helminths and Plasmodium; in some, the burden of Plasmodium parasites increased, but others reported a reduction in the parasite. This review focuses on explaining many of these discrepancies regarding helminth-Plasmodium coinfections in terms of the effects that helminths have on the immune system. In particular, it focuses on helminth-induced immunosuppression and the effects of cytokines controlling polarization toward the Th1 or Th2 arms of the immune response.

Genetics and evolution of triatomines: from phylogeny to vector control

PubMed Central

Gourbière, S; Dorn, P; Tripet, F; Dumonteil, E

2012-01-01

Triatomines are hemipteran bugs acting as vectors of the protozoan parasite Trypanosoma cruzi. This parasite causes Chagas disease, one of the major parasitic diseases in the Americas. Studies of triatomine genetics and evolution have been particularly useful in the design of rational vector control strategies, and are reviewed here. The phylogeography of several triatomine species is now slowly emerging, and the struggle to reconcile the phenotypic, phylogenetic, ecological and epidemiological species concepts makes for a very dynamic field. Population genetic studies using different markers indicate a wide range of population structures, depending on the triatomine species, ranging from highly fragmented to mobile, interbreeding populations. Triatomines transmit T. cruzi in the context of complex interactions between the insect vectors, their bacterial symbionts and the parasites; however, an integrated view of the significance of these interactions in triatomine biology, evolution and in disease transmission is still lacking. The development of novel genetic markers, together with the ongoing sequencing of the Rhodnius prolixus genome and more integrative studies, will provide key tools to expanding our understanding of these important insect vectors and allow the design of improved vector control strategies. PMID:21897436

Impact of natural control agents of the citrus leafminer Phyllocnistis citrella on lemon trees varies among seasons.

PubMed

Goane, L; Casmuz, A; Salas, H; Willink, E; Mangeaud, A; Valladares, G

2015-12-01

Studies on insect natural enemies and their effects on host populations are of immense practical value in pest management. Predation and parasitism on a citrus pest, the leafminer Phyllocnistis citrella Stainton, were evaluated by sampling over 3 years in four locations within a world leading lemon producing area in Northwest Argentina. Both mortality factors showed seasonal trends consistent across locations, with predation exerting earlier and more sustained pressure than parasitism, which showed wider seasonal variations. The dominant parasitoids, native Cirrospilus neotropicus and introduced Ageniaspis citricola, showed different seasonal trends: C. neotropicus was dominant in spring whereas A. citricola superseded it in autumn and winter. Although parasitism rates were relatively low, the native C. neotropicus revealed favourable features as potential control agent, by showing density-dependence, parasitism rates comparable with those of the specific A. citricola during part of the cycle, and earlier synchronization with the host. The study provides highly relevant information for a sustainable management of this worldwide pest, for which biological control is considered the best long-term option.

Modelling Parasite Transmission in a Grazing System: The Importance of Host Behaviour and Immunity

PubMed Central

Fox, Naomi J.; Marion, Glenn; Davidson, Ross S.; White, Piran C. L.; Hutchings, Michael R.

2013-01-01

Parasitic helminths present one of the most pervasive challenges to grazing herbivores. Many macro-parasite transmission models focus on host physiological defence strategies, omitting more complex interactions between hosts and their environments. This work represents the first model that integrates both the behavioural and physiological elements of gastro-intestinal nematode transmission dynamics in a managed grazing system. A spatially explicit, individual-based, stochastic model is developed, that incorporates both the hosts’ immunological responses to parasitism, and key grazing behaviours including faecal avoidance. The results demonstrate that grazing behaviour affects both the timing and intensity of parasite outbreaks, through generating spatial heterogeneity in parasite risk and nutritional resources, and changing the timing of exposure to the parasites’ free-living stages. The influence of grazing behaviour varies with the host-parasite combination, dependent on the development times of different parasite species and variations in host immune response. Our outputs include the counterintuitive finding that under certain conditions perceived parasite avoidance behaviours (faecal avoidance) can increase parasite risk, for certain host-parasite combinations. Through incorporating the two-way interaction between infection dynamics and grazing behaviour, the potential benefits of parasite-induced anorexia are also demonstrated. Hosts with phenotypic plasticity in grazing behaviour, that make grazing decisions dependent on current parasite burden, can reduce infection with minimal loss of intake over the grazing season. This paper explores how both host behaviours and immunity influence macro-parasite transmission in a spatially and temporally heterogeneous environment. The magnitude and timing of parasite outbreaks is influenced by host immunity and behaviour, and the interactions between them; the incorporation of both regulatory processes is required to fully understand transmission dynamics. Understanding of both physiological and behavioural defence strategies will aid the development of novel approaches for control. PMID:24223133

Parasitism by Cuscuta pentagona Attenuates Host Plant Defenses against Insect Herbivores1

PubMed Central

Runyon, Justin B.; Mescher, Mark C.; De Moraes, Consuelo M.

2008-01-01

Considerable research has examined plant responses to concurrent attack by herbivores and pathogens, but the effects of attack by parasitic plants, another important class of plant-feeding organisms, on plant defenses against other enemies has not been explored. We investigated how attack by the parasitic plant Cuscuta pentagona impacted tomato (Solanum lycopersicum) defenses against the chewing insect beet armyworm (Spodoptera exigua; BAW). In response to insect feeding, C. pentagona-infested (parasitized) tomato plants produced only one-third of the antiherbivore phytohormone jasmonic acid (JA) produced by unparasitized plants. Similarly, parasitized tomato, in contrast to unparasitized plants, failed to emit herbivore-induced volatiles after 3 d of BAW feeding. Although parasitism impaired antiherbivore defenses, BAW growth was slower on parasitized tomato leaves. Vines of C. pentagona did not translocate JA from BAW-infested plants: amounts of JA in parasite vines grown on caterpillar-fed and control plants were similar. Parasitized plants generally contained more salicylic acid (SA), which can inhibit JA in some systems. Parasitized mutant (NahG) tomato plants deficient in SA produced more JA in response to insect feeding than parasitized wild-type plants, further suggesting cross talk between the SA and JA defense signaling pathways. However, JA induction by BAW was still reduced in parasitized compared to unparasitized NahG, implying that other factors must be involved. We found that parasitized plants were capable of producing induced volatiles when experimentally treated with JA, indicating that resource depletion by the parasite does not fully explain the observed attenuation of volatile response to herbivore feeding. Collectively, these findings show that parasitic plants can have important consequences for host plant defense against herbivores. PMID:18165323

Parasitism by Cuscuta pentagona attenuates host plant defenses against insect herbivores.

PubMed

Runyon, Justin B; Mescher, Mark C; De Moraes, Consuelo M

2008-03-01

Considerable research has examined plant responses to concurrent attack by herbivores and pathogens, but the effects of attack by parasitic plants, another important class of plant-feeding organisms, on plant defenses against other enemies has not been explored. We investigated how attack by the parasitic plant Cuscuta pentagona impacted tomato (Solanum lycopersicum) defenses against the chewing insect beet armyworm (Spodoptera exigua; BAW). In response to insect feeding, C. pentagona-infested (parasitized) tomato plants produced only one-third of the antiherbivore phytohormone jasmonic acid (JA) produced by unparasitized plants. Similarly, parasitized tomato, in contrast to unparasitized plants, failed to emit herbivore-induced volatiles after 3 d of BAW feeding. Although parasitism impaired antiherbivore defenses, BAW growth was slower on parasitized tomato leaves. Vines of C. pentagona did not translocate JA from BAW-infested plants: amounts of JA in parasite vines grown on caterpillar-fed and control plants were similar. Parasitized plants generally contained more salicylic acid (SA), which can inhibit JA in some systems. Parasitized mutant (NahG) tomato plants deficient in SA produced more JA in response to insect feeding than parasitized wild-type plants, further suggesting cross talk between the SA and JA defense signaling pathways. However, JA induction by BAW was still reduced in parasitized compared to unparasitized NahG, implying that other factors must be involved. We found that parasitized plants were capable of producing induced volatiles when experimentally treated with JA, indicating that resource depletion by the parasite does not fully explain the observed attenuation of volatile response to herbivore feeding. Collectively, these findings show that parasitic plants can have important consequences for host plant defense against herbivores.

Interspecific RNA Interference of SHOOT MERISTEMLESS-Like Disrupts Cuscuta pentagona Plant Parasitism[C][W][OA

PubMed Central

Alakonya, Amos; Kumar, Ravi; Koenig, Daniel; Kimura, Seisuke; Townsley, Brad; Runo, Steven; Garces, Helena M.; Kang, Julie; Yanez, Andrea; David-Schwartz, Rakefet; Machuka, Jesse; Sinha, Neelima

2012-01-01

Infection of crop species by parasitic plants is a major agricultural hindrance resulting in substantial crop losses worldwide. Parasitic plants establish vascular connections with the host plant via structures termed haustoria, which allow acquisition of water and nutrients, often to the detriment of the infected host. Despite the agricultural impact of parasitic plants, the molecular and developmental processes by which host/parasitic interactions are established are not well understood. Here, we examine the development and subsequent establishment of haustorial connections by the parasite dodder (Cuscuta pentagona) on tobacco (Nicotiana tabacum) plants. Formation of haustoria in dodder is accompanied by upregulation of dodder KNOTTED-like homeobox transcription factors, including SHOOT MERISTEMLESS-like (STM). We demonstrate interspecific silencing of a STM gene in dodder driven by a vascular-specific promoter in transgenic host plants and find that this silencing disrupts dodder growth. The reduced efficacy of dodder infection on STM RNA interference transgenics results from defects in haustorial connection, development, and establishment. Identification of transgene-specific small RNAs in the parasite, coupled with reduced parasite fecundity and increased growth of the infected host, demonstrates the efficacy of interspecific small RNA–mediated silencing of parasite genes. This technology has the potential to be an effective method of biological control of plant parasite infection. PMID:22822208

Interspecific RNA interference of SHOOT MERISTEMLESS-like disrupts Cuscuta pentagona plant parasitism.

PubMed

Alakonya, Amos; Kumar, Ravi; Koenig, Daniel; Kimura, Seisuke; Townsley, Brad; Runo, Steven; Garces, Helena M; Kang, Julie; Yanez, Andrea; David-Schwartz, Rakefet; Machuka, Jesse; Sinha, Neelima

2012-07-01

Infection of crop species by parasitic plants is a major agricultural hindrance resulting in substantial crop losses worldwide. Parasitic plants establish vascular connections with the host plant via structures termed haustoria, which allow acquisition of water and nutrients, often to the detriment of the infected host. Despite the agricultural impact of parasitic plants, the molecular and developmental processes by which host/parasitic interactions are established are not well understood. Here, we examine the development and subsequent establishment of haustorial connections by the parasite dodder (Cuscuta pentagona) on tobacco (Nicotiana tabacum) plants. Formation of haustoria in dodder is accompanied by upregulation of dodder KNOTTED-like homeobox transcription factors, including SHOOT MERISTEMLESS-like (STM). We demonstrate interspecific silencing of a STM gene in dodder driven by a vascular-specific promoter in transgenic host plants and find that this silencing disrupts dodder growth. The reduced efficacy of dodder infection on STM RNA interference transgenics results from defects in haustorial connection, development, and establishment. Identification of transgene-specific small RNAs in the parasite, coupled with reduced parasite fecundity and increased growth of the infected host, demonstrates the efficacy of interspecific small RNA-mediated silencing of parasite genes. This technology has the potential to be an effective method of biological control of plant parasite infection.

Heterogeneities in Leishmania infantum Infection: Using Skin Parasite Burdens to Identify Highly Infectious Dogs

PubMed Central

Calvo-Bado, Leo; Garcez, Lourdes M.; Quinnell, Rupert J.

2014-01-01

Background The relationships between heterogeneities in host infection and infectiousness (transmission to arthropod vectors) can provide important insights for disease management. Here, we quantify heterogeneities in Leishmania infantum parasite numbers in reservoir and non-reservoir host populations, and relate this to their infectiousness during natural infection. Tissue parasite number was evaluated as a potential surrogate marker of host transmission potential. Methods Parasite numbers were measured by qPCR in bone marrow and ear skin biopsies of 82 dogs and 34 crab-eating foxes collected during a longitudinal study in Amazon Brazil, for which previous data was available on infectiousness (by xenodiagnosis) and severity of infection. Results Parasite numbers were highly aggregated both between samples and between individuals. In dogs, total parasite abundance and relative numbers in ear skin compared to bone marrow increased with the duration and severity of infection. Infectiousness to the sandfly vector was associated with high parasite numbers; parasite number in skin was the best predictor of being infectious. Crab-eating foxes, which typically present asymptomatic infection and are non-infectious, had parasite numbers comparable to those of non-infectious dogs. Conclusions Skin parasite number provides an indirect marker of infectiousness, and could allow targeted control particularly of highly infectious dogs. PMID:24416460

Do native parasitic plants cause more damage to exotic invasive hosts than native non-invasive hosts? An implication for biocontrol.

PubMed

Li, Junmin; Jin, Zexin; Song, Wenjing

2012-01-01

Field studies have shown that native, parasitic plants grow vigorously on invasive plants and can cause more damage to invasive plants than native plants. However, no empirical test has been conducted and the mechanism is still unknown. We conducted a completely randomized greenhouse experiment using 3 congeneric pairs of exotic, invasive and native, non-invasive herbaceous plant species to quantify the damage caused by parasitic plants to hosts and its correlation with the hosts' growth rate and resource use efficiency. The biomass of the parasitic plants on exotic, invasive hosts was significantly higher than on congeneric native, non-invasive hosts. Parasites caused more damage to exotic, invasive hosts than to congeneric, native, non-invasive hosts. The damage caused by parasites to hosts was significantly positively correlated with the biomass of parasitic plants. The damage of parasites to hosts was significantly positively correlated with the relative growth rate and the resource use efficiency of its host plants. It may be the mechanism by which parasitic plants grow more vigorously on invasive hosts and cause more damage to exotic, invasive hosts than to native, non-invasive hosts. These results suggest a potential biological control effect of native, parasitic plants on invasive species by reducing the dominance of invasive species in the invaded community.

Designing for Damage: Robust Flight Control Design using Sliding Mode Techniques

NASA Technical Reports Server (NTRS)

Vetter, T. K.; Wells, S. R.; Hess, Ronald A.; Bacon, Barton (Technical Monitor); Davidson, John (Technical Monitor)

2002-01-01

A brief review of sliding model control is undertaken, with particular emphasis upon the effects of neglected parasitic dynamics. Sliding model control design is interpreted in the frequency domain. The inclusion of asymptotic observers and control 'hedging' is shown to reduce the effects of neglected parasitic dynamics. An investigation into the application of observer-based sliding mode control to the robust longitudinal control of a highly unstable is described. The sliding mode controller is shown to exhibit stability and performance robustness superior to that of a classical loop-shaped design when significant changes in vehicle and actuator dynamics are employed to model airframe damage.

Methodological issues affecting the study of fish parasites. III. Effect of fish preservation method.

PubMed

Kvach, Yuriy; Ondračková, Markéta; Janáč, Michal; Jurajda, Pavel

2018-03-05

The aim of this study was to evaluate the influence of preservation method on the results of parasite community studies. Two host species, European perch Perca fluviatilis and European bitterling Rhodeus amarus, were examined for parasites after having been subjected to 4 different storage treatments: freezing, preservation in 4% formaldehyde or 70% ethanol and transportation of live (fresh) fish as a control. Preservation prior to dissection resulted in a loss of information, leading to incomplete quantitative data (all preservation treatments), qualitative data (ethanol and formaldehyde preservation) and a lowered ability to determine parasites to species level based on morphology compared to dissecting fresh fish. Of the more abundant taxa, only crustaceans and acanthocephalans provided relatively even results between treatments. We conclude that preservation media, such as ethanol or formaldehyde, significantly affects the ability to obtain precise parasite community data; hence, we recommend the use of freshly sacrificed fish for parasite community studies whenever possible. Alternatively, freezing may prove acceptable for evaluating parasite community taxonomic composition.

Stress and sex in malaria parasites: Why does commitment vary?

PubMed

Carter, Lucy M; Kafsack, Björn F C; Llinás, Manuel; Mideo, Nicole; Pollitt, Laura C; Reece, Sarah E

2013-01-01

For vector-borne parasites such as malaria, how within- and between-host processes interact to shape transmission is poorly understood. In the host, malaria parasites replicate asexually but for transmission to occur, specialized sexual stages (gametocytes) must be produced. Despite the central role that gametocytes play in disease transmission, explanations of why parasites adjust gametocyte production in response to in-host factors remain controversial. We propose that evolutionary theory developed to explain variation in reproductive effort in multicellular organisms, provides a framework to understand gametocyte investment strategies. We examine why parasites adjust investment in gametocytes according to the impact of changing conditions on their in-host survival. We then outline experiments required to determine whether plasticity in gametocyte investment enables parasites to maintain fitness in a variable environment. Gametocytes are a target for anti-malarial transmission-blocking interventions so understanding plasticity in investment is central to maximizing the success of control measures in the face of parasite evolution.

Plasmodium falciparum: attenuation by irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Waki, S.; Yonome, I.; Suzuki, M.

The effect of irradiation on the in vitro growth of Plasmodium falciparum was investigated. The cultured malarial parasites at selected stages of development were exposed to gamma rays and the sensitivity of each stage was determined. The stages most sensitive to irradiation were the ring forms and the early trophozoites; late trophozoites were relatively insensitive. The greatest resistance was shown when parasites were irradiated at a time of transition from the late trophozoite and schizont stages to young ring forms. The characteristics of radiosensitive variation in the parasite cycle resembled that of mammalian cells. Growth curves of parasites exposed tomore » doses of irradiation upto 150 gray had the same slope as nonirradiated controls but parasites which were exposed to 200 gray exhibited a growth curve which was less steep than that for parasites in other groups. Less than 10 organisms survived from the 10(6) parasites exposed to this high dose of irradiation; the possibility exists of obtaining radiation-attenuated P. falciparum.« less

Parasitic diseases of the central nervous system: lessons for clinicians and policy makers

PubMed Central

Carpio, Arturo; Romo, Matthew L.; Parkhouse, R. M. E.; Short, Brooke; Dua, Tarun

2016-01-01

ABSTRACT Parasitic diseases of the central nervous system are associated with high mortality and morbidity, especially in resource-limited settings. The burden of these diseases is amplified as survivors are often left with neurologic sequelae affecting mobility, sensory organs, and cognitive functions, as well as seizures/epilepsy. These diseases inflict suffering by causing lifelong disabilities, reducing economic productivity, and causing social stigma. The complexity of parasitic life cycles and geographic specificities, as well as overlapping clinical manifestations in the host reflecting the diverse pathogenesis of parasites, can present diagnostic challenges. We herein provide an overview of these parasitic diseases and summarize clinical aspects, diagnosis, therapeutic strategies and recent milestones, and aspects related to prevention and control. PMID:26894629

The Effects of Herbicides Targeting Aromatic and Branched Chain Amino Acid Biosynthesis Support the Presence of Functional Pathways in Broomrape.

PubMed

Dor, Evgenia; Galili, Shmuel; Smirnov, Evgeny; Hacham, Yael; Amir, Rachel; Hershenhorn, Joseph

2017-01-01

It is not clear why herbicides targeting aromatic and branched-chain amino acid biosynthesis successfully control broomrapes-obligate parasitic plants that obtain all of their nutritional requirements, including amino acids, from the host. Our objective was to reveal the mode of action of imazapic and glyphosate in controlling the broomrape Phelipanche aegyptiaca and clarify if this obligatory parasite has its own machinery for the amino acids biosynthesis. P. aegyptiaca callus was studied to exclude the indirect influence of the herbicides on the parasite through the host plant. Using HRT - tomato plants resistant to imidazolinone herbicides, it was shown that imazapic is translocated from the foliage of treated plants to broomrape attachments on its roots and controls the parasite. Both herbicides inhibited P. aegyptiaca callus growth and altered the free amino acid content. Blasting of Arabidopsis thaliana 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) and acetolactate synthase (ALS) cDNA against the genomic DNA of P. aegyptiaca yielded a single copy of each homolog in the latter, with about 78 and 75% similarity, respectively, to A. thaliana counterparts at the protein level. We also show for the first time that both EPSPS and ALS are active in P. aegyptiaca callus and flowering shoots and are inhibited by glyphosate and imazapic, respectively. Thus leading to deficiency of those amino acids in the parasite tissues and ultimately, death of the parasite, indicating the ability of P. aegyptiaca to synthesize branched-chain and aromatic amino acids through the activity of ALS and EPSPS, respectively.

The Effects of Herbicides Targeting Aromatic and Branched Chain Amino Acid Biosynthesis Support the Presence of Functional Pathways in Broomrape

PubMed Central

Dor, Evgenia; Galili, Shmuel; Smirnov, Evgeny; Hacham, Yael; Amir, Rachel; Hershenhorn, Joseph

2017-01-01

It is not clear why herbicides targeting aromatic and branched-chain amino acid biosynthesis successfully control broomrapes—obligate parasitic plants that obtain all of their nutritional requirements, including amino acids, from the host. Our objective was to reveal the mode of action of imazapic and glyphosate in controlling the broomrape Phelipanche aegyptiaca and clarify if this obligatory parasite has its own machinery for the amino acids biosynthesis. P. aegyptiaca callus was studied to exclude the indirect influence of the herbicides on the parasite through the host plant. Using HRT – tomato plants resistant to imidazolinone herbicides, it was shown that imazapic is translocated from the foliage of treated plants to broomrape attachments on its roots and controls the parasite. Both herbicides inhibited P. aegyptiaca callus growth and altered the free amino acid content. Blasting of Arabidopsis thaliana 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) and acetolactate synthase (ALS) cDNA against the genomic DNA of P. aegyptiaca yielded a single copy of each homolog in the latter, with about 78 and 75% similarity, respectively, to A. thaliana counterparts at the protein level. We also show for the first time that both EPSPS and ALS are active in P. aegyptiaca callus and flowering shoots and are inhibited by glyphosate and imazapic, respectively. Thus leading to deficiency of those amino acids in the parasite tissues and ultimately, death of the parasite, indicating the ability of P. aegyptiaca to synthesize branched-chain and aromatic amino acids through the activity of ALS and EPSPS, respectively. PMID:28523011

High rate of adaptation of mammalian proteins that interact with Plasmodium and related parasites

PubMed Central

Telis, Natalie; Petrov, Dmitri A.

2017-01-01

Plasmodium parasites, along with their Piroplasm relatives, have caused malaria-like illnesses in terrestrial mammals for millions of years. Several Plasmodium-protective alleles have recently evolved in human populations, but little is known about host adaptation to blood parasites over deeper evolutionary timescales. In this work, we analyze mammalian adaptation in ~500 Plasmodium- or Piroplasm- interacting proteins (PPIPs) manually curated from the scientific literature. We show that (i) PPIPs are enriched for both immune functions and pleiotropy with other pathogens, and (ii) the rate of adaptation across mammals is significantly elevated in PPIPs, compared to carefully matched control proteins. PPIPs with high pathogen pleiotropy show the strongest signatures of adaptation, but this pattern is fully explained by their immune enrichment. Several pieces of evidence suggest that blood parasites specifically have imposed selection on PPIPs. First, even non-immune PPIPs that lack interactions with other pathogens have adapted at twice the rate of matched controls. Second, PPIP adaptation is linked to high expression in the liver, a critical organ in the parasite life cycle. Finally, our detailed investigation of alpha-spectrin, a major red blood cell membrane protein, shows that domains with particularly high rates of adaptation are those known to interact specifically with P. falciparum. Overall, we show that host proteins that interact with Plasmodium and Piroplasm parasites have experienced elevated rates of adaptation across mammals, and provide evidence that some of this adaptation has likely been driven by blood parasites. PMID:28957326

LABCG2, a New ABC Transporter Implicated in Phosphatidylserine Exposure, Is Involved in the Infectivity and Pathogenicity of Leishmania

PubMed Central

González-Rey, Elena; Delgado, Mario; Castanys, Santiago; Pérez-Victoria, José M.; Gamarro, Francisco

2013-01-01

Leishmaniasis is a neglected disease produced by the intracellular protozoan parasite Leishmania. In the present study, we show that LABCG2, a new ATP-binding cassette half-transporter (ABCG subfamily) from Leishmania, is involved in parasite virulence. Down-regulation of LABCG2 function upon expression of an inactive mutant version of this half-transporter (LABCG2K/M) is shown to reduce the translocation of short-chain analogues of phosphatidylserine (PS). This dominant-negative phenotype is specific for the headgroup of the phospholipid, as the movement of phospholipid analogues of phosphatidylcholine, phosphatidylethanolamine or sphingomyelin is not affected. In addition, promastigotes expressing LABCG2K/M expose less endogenous PS in the stationary phase than control parasites. Transient exposure of PS at the outer leaflet of the plasma membrane is known to be one of the mechanisms used by Leishmania to infect macrophages and to silence their immune response. Stationary phase/metacyclic promastigotes expressing LABCG2K/M are less infective for macrophages and show decreased pathogenesis in a mouse model of cutaneous leishmaniasis. Thus, mice infected with parasites expressing LABCG2K/M did not develop any lesion and showed significantly lower inflammation and parasite burden than mice infected with control parasites. Our results indicate that LABCG2 function is required for the externalization of PS in Leishmania promastigotes, a process that is involved in the virulence of the parasite. PMID:23638200

Randomized Controlled Trial of Levamisole Hydrochloride as Adjunctive Therapy in Severe Falciparum Malaria With High Parasitemia

PubMed Central

Maude, Richard J.; Silamut, Kamolrat; Plewes, Katherine; Charunwatthana, Prakaykaew; Ho, May; Abul Faiz, M.; Rahman, Ridwanur; Hossain, Md Amir; Hassan, Mahtab U.; Bin Yunus, Emran; Hoque, Gofranul; Islam, Faridul; Ghose, Aniruddha; Hanson, Josh; Schlatter, Joel; Lacey, Rachel; Eastaugh, Alison; Tarning, Joel; Lee, Sue J.; White, Nicholas J.; Chotivanich, Kesinee; Day, Nicholas P. J.; Dondorp, Arjen M.

2014-01-01

Background. Cytoadherence and sequestration of erythrocytes containing mature stages of Plasmodium falciparum are central to the pathogenesis of severe malaria. The oral anthelminthic drug levamisole inhibits cytoadherence in vitro and reduces sequestration of late-stage parasites in uncomplicated falciparum malaria treated with quinine. Methods. Fifty-six adult patients with severe malaria and high parasitemia admitted to a referral hospital in Bangladesh were randomized to receive a single dose of levamisole hydrochloride (150 mg) or no adjuvant to antimalarial treatment with intravenous artesunate. Results. Circulating late-stage parasites measured as the median area under the parasite clearance curves were 2150 (interquartile range [IQR], 0–28 025) parasites/µL × hour in patients treated with levamisole and 5489 (IQR, 192–25 848) parasites/µL × hour in controls (P = .25). The “sequestration ratios” at 6 and 12 hours for all parasite stages and changes in microvascular blood flow did not differ between treatment groups (all P > .40). The median time to normalization of plasma lactate (<2 mmol/L) was 24 (IQR, 12–30) hours with levamisole vs 28 (IQR, 12–36) hours without levamisole (P = .15). Conclusions. There was no benefit of a single-dose of levamisole hydrochloride as adjuvant to intravenous artesunate in the treatment of adults with severe falciparum malaria. Rapid parasite killing by intravenous artesunate might obscure the effects of levamisole. PMID:23943850

Effect of oral washes on the diagnosis of Pneumocystis carinii pneumonia with a low parasite burden and on detection of organisms in subclinical infections.

PubMed

Matos, O; Costa, M C; Lundgren, B; Caldeira, L; Aguiar, P; Antunes, F

2001-08-01

This study was designed to assess the efficacy of using oral washes (OWs) to diagnose Pneumocystis carinii pneumonia (PCP) in patients with a low parasite burden and to detect cases of subclinical infection. A total of 104 paired induced sputum (IS) samples and OWs from 104 HIV-seropositive patients and 32 OWs from immunocompetent healthy controls were studied. All of the control samples were negative. Fifty-two IS specimens were positive for Pneumocystis carinii, and 26 of these cases were also detected in the OWs using conventional stain or polymerase chain reaction. Twenty-four of the PCP cases had a high or a moderate parasite load and 28 had a low parasite load; among them, Pneumocystis carinii was detected in the OWs of 15 and 11 cases, respectively. Fifteen of the 104 IS samples studied belonged to patients who were asymptomatic carriers or who had a subclinical infection, and Pneumocystis carinii was detected in the OWs of 4 of these cases. The parasite was not detected in 37 IS samples and in 74 OWs. The results of this study indicate that in patients with a low pulmonary parasite burden, the number of organisms reaching the oral cavity is insufficient for reliable detection in OWs. Thus, OWs are less useful than IS samples for detecting Pneumocystis carinii in cases of pneumonia in which a low parasite burden and/or subclinical infection are present.

Highly sensitive and specific detection of Giardia duodenalis, Entamoeba histolytica, and Cryptosporidium spp. in human stool samples by the BD MAX™ Enteric Parasite Panel.

PubMed

Parčina, Marijo; Reiter-Owona, Ingrid; Mockenhaupt, Frank P; Vojvoda, Valerija; Gahutu, Jean Bosco; Hoerauf, Achim; Ignatius, Ralf

2018-02-01

Detection of intestinal protozoan parasites by light microscopy is cumbersome, needs experienced personnel, and may lack sensitivity and/or specificity as compared with molecular-based stool assays. Here, we evaluated the BD MAX™ Enteric Parasite Panel, i.e., a multiplex real-time PCR assay for simultaneous detection of Giardia duodenalis, Entamoeba histolytica, and cryptosporidia (Cryptosporidium parvum and C. hominis), by examining 200 positive human stool samples (138 × G. duodenalis, 27 × E. histolytica, 35 × Cryptosporidium spp.) and 119 controls including 18 samples with E. dispar. The majority of the samples, i.e., 153/200 (76.5%) positive samples and 66/119 (55.5%) controls, were confirmed by multiplex in-house PCR detecting the same parasites as the BD MAX™ Enteric Parasite Panel. The BD MAX™ assay did not yield false-positive results. Sensitivity and specificity were 97.8% (95% CI, 93.3-99.4%) and 100% (95% CI, 97.4-100%) for G. duodenalis, 100% (95% CI, 84.5-100%) and 100% (95% CI, 98.4-100%) for E. histolytica, and 100% (95% CI, 87.7-100%) and 100% (95% CI, 98.3-100%) for cryptosporidia, and similar data were obtained when only the 219 PCR-confirmed samples were analyzed. Thus, the BD MAX™ Enteric Parasite Panel provides a highly sensitive and specific tool for the laboratory diagnosis of three predominant protozoan parasites causing enteritis.

Best linear unbiased prediction of host range of the facultative parasite Colletotrichum gloeosporioides f. sp. salsolae, a potential biological control agent of Russian thistle

USDA-ARS?s Scientific Manuscript database

Tumbleweed or Russian thistle (Salsola tragus L.) is an introduced invasive weed in N. America. It is widely distributed in the U.S. and is a target of biological control efforts. The facultative parasitic fungus Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. in Penz. f. sp. salsolae is a po...

Foals raised on pasture with or without daily pyrantel tartrate feed additive: comparison of parasite burdens and host responses following experimental challenge with large and small strongyle larvae.

PubMed

Monahan, C M; Chapman, M R; Taylor, H W; French, D D; Klei, T R

1997-12-31

Three groups of foals were raised under different management programs in this study: Group 1 (n = 6) and Group 2 (n = 6) were raised with their dams on pasture; Group 3 foals (n = 5) were raised under parasite-free conditions. Mares and foals of Group 1 received daily pyrantel tartrate (PT) treatment with their pelleted feed ration, whereas mares and foals of Groups 2 and 3 received only the pelleted ration. Pasture-reared foals were weaned and moved to a heavily contaminated pasture for 5 weeks. Group 1 foals continued to receive daily PT treatment whereas Group 2 foals received only the pelleted feed ration. Following this period, all foals were moved into box stalls. Half of each group was challenged with 10(3) Strongylus vulgaris infective third-stage larvae (L3), 5 x 10(3) Strongylus edentatus L3 and 10(5) mixed cyathostome L3; the remaining half served as unchallenged controls. Necropsy examinations were performed 6-week post-challenge for evaluation of parasite burdens and lesions. Daily PT treatment of Group 1 reduced the patent cyathostome infections of both mares and foals and was effective in reducing pasture burdens of infective larvae. Daily treatment of Group 1 foals during weaning continued to suppress EPG levels; however, it did not prevent large strongyle infections during the weaning period. Group 1 foals were more sensitive to challenge than Group 2 foals, which did not exhibit any post-challenge disturbances. Group 1 foals were equally susceptible to challenge as parasite-free foals.

Synthetic peptide vaccine against Taenia solium pig cysticercosis: successful vaccination in a controlled field trial in rural Mexico.

PubMed

Huerta, M; de Aluja, A S; Fragoso, G; Toledo, A; Villalobos, N; Hernández, M; Gevorkian, G; Acero, G; Díaz, A; Alvarez, I; Avila, R; Beltrán, C; Garcia, G; Martinez, J J; Larralde, C; Sciutto, E

2001-10-12

Taenia solium cysticercosis seriously affects human health when localised in the central nervous system (CNS) and causes great economic loss in pig husbandry in rural areas of endemic countries. Increasing the resistance to the parasite in the obligatory host pig may help in curbing transmission. Three synthetic peptides based on protein sequences of the murine parasite Taenia crassiceps, which had previously been shown to induce protection in mice against homologous challenge, were tested as a vaccine against T. solium cysticercosis in pigs. Vaccinated and unvaccinated piglets (240 in all) were distributed in pairs among the peasants' households of two rural villages in Mexico in which 14% of the native pigs were cysticercotic. Ten to twelve months later, the effect of vaccination was evaluated at necropsy. Vaccination decreased the total number of T. solium cysticerci (98.7%) and reduced the prevalence (52.6%). The natural challenge conditions used in this field trial strengthen the likelihood of successful transmission control to both pig and human through a large-scale pig vaccination program. We believe this is a major contribution in anticysticercosis vaccine development as these rather simple yet protective peptides are potentially more cost-effective to produce and less variable in results than antigens that are more complex.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fryer, John L.

The Department of Microbiology at Oregon State University with funding from the Bonneville Power Administration has been conducting a study concerning the epidemiology and control of three fish pathogens which cause major disease problems in salmonids of the Columbia River basin. The pathogens studied include Cera to myxa Shasta, the myxosporean parasite which causes ceratomyxosis; Renibacterium salmoninarum, the bacterium which is the etiological agent of bacterial kidney disease; and the rhabdovirus which causes infectious hematopoietic necrosis (IHN). During this project, the host and geographic range of C. Shasta have been more precisely determined and the known geographic range has beenmore » significantly expanded. The effects of the parasite on fish migrating through the Columbia River and on their introduction into salt water have been examined. Similar studies have been conducted with R. salmoninarum and it has been shown that bacterial kidney disease occurs at all life stages of salmonids and is responsible for mortality in both fresh and salt water. It has also been demonstrated that different isolates of R. salmoninarum have different antigenic composition. Results of demonstration projects designed to control IHN by using UV treated water for early rearing of salmonid fry were equivocal. The scope of the project was considerably narrowed and focused during the past two years The project has concentrated on a study concerning the biology of C. Shasta and the identification of potential chemotherapeutants for control of bacterial kidney disease. The emphasis of work on C. Shasta has been its pathogenesis. This aspect of the parasite has been investigated using histopathologic and immunologic methodology. Mode of transmission, the nature of the infectious stage, and potential intermediate hosts of the parasite have also been areas of active research. Classes of chemotherapeutants with the highest potential for efficacy against R. salmoninarum have been identified through literature searches and consultation with pharmacologists. Experimental drugs have been requested and received from several pharmaceutical manufacturers. The in vitro sensitivity of R. salmoninarum and other selected fish pathogens to more than 100 antimicrobial compounds has been tested. The project is related to measure 704(h)(2)(d) of the Columbia River Basin Fish and Wildlife Program. The results will contribute to fish health which will directly contribute to the protection of fish.« less

RNA mobility in parasitic plant – host interactions

PubMed Central

Kim, Gunjune

2017-01-01

ABSTRACT The parasitic plant Cuscuta exchanges mRNAs with its hosts. Systemic mobility of mRNAs within plants is well documented, and has gained increasing attention as studies using grafted plant systems have revealed new aspects of mobile mRNA regulation and function. But parasitic plants take this phenomenon to a new level by forming seamless connections to a wide range of host species, and raising questions about how mRNAs might function after transfer to a different species. Cuscuta and other parasitic plant species also take siRNAs from their hosts, indicating that multiple types of RNA are capable of trans-specific movement. Parasitic plants are intriguing systems for studying RNA mobility, in part because such exchange opens new possibilities for control of parasitic weeds, but also because they provide a fresh perspective into understanding roles of RNAs in inter-organismal communication. PMID:28277936

Host nutrition alters the variance in parasite transmission potential

PubMed Central

Vale, Pedro F.; Choisy, Marc; Little, Tom J.

2013-01-01

The environmental conditions experienced by hosts are known to affect their mean parasite transmission potential. How different conditions may affect the variance of transmission potential has received less attention, but is an important question for disease management, especially if specific ecological contexts are more likely to foster a few extremely infectious hosts. Using the obligate-killing bacterium Pasteuria ramosa and its crustacean host Daphnia magna, we analysed how host nutrition affected the variance of individual parasite loads, and, therefore, transmission potential. Under low food, individual parasite loads showed similar mean and variance, following a Poisson distribution. By contrast, among well-nourished hosts, parasite loads were right-skewed and overdispersed, following a negative binomial distribution. Abundant food may, therefore, yield individuals causing potentially more transmission than the population average. Measuring both the mean and variance of individual parasite loads in controlled experimental infections may offer a useful way of revealing risk factors for potential highly infectious hosts. PMID:23407498

Host nutrition alters the variance in parasite transmission potential.

PubMed

Vale, Pedro F; Choisy, Marc; Little, Tom J

2013-04-23

The environmental conditions experienced by hosts are known to affect their mean parasite transmission potential. How different conditions may affect the variance of transmission potential has received less attention, but is an important question for disease management, especially if specific ecological contexts are more likely to foster a few extremely infectious hosts. Using the obligate-killing bacterium Pasteuria ramosa and its crustacean host Daphnia magna, we analysed how host nutrition affected the variance of individual parasite loads, and, therefore, transmission potential. Under low food, individual parasite loads showed similar mean and variance, following a Poisson distribution. By contrast, among well-nourished hosts, parasite loads were right-skewed and overdispersed, following a negative binomial distribution. Abundant food may, therefore, yield individuals causing potentially more transmission than the population average. Measuring both the mean and variance of individual parasite loads in controlled experimental infections may offer a useful way of revealing risk factors for potential highly infectious hosts.

Immunity against Helminths: Interactions with the Host and the Intercurrent Infections

PubMed Central

Moreau, Emmanuelle; Chauvin, Alain

2010-01-01

Helminth parasites are of considerable medical and economic importance. Studies of the immune response against helminths are of great interest in understanding interactions between the host immune system and parasites. Effector immune mechanisms against tissue-dwelling helminths and helminths localized in the lumen of organs, and their regulation, are reviewed. Helminth infections are characterized by an association of Th2-like and Treg responses. Worms are able to persist in the host and are mainly responsible for chronic infection despite a strong immune response developed by the parasitized host. Two types of protection against the parasite, namely, premune and partial immunities, have been described. Immune responses against helminths can also participate in pathogenesis. Th2/Treg-like immunomodulation allows the survival of both host and parasite by controlling immunopathologic disorders and parasite persistence. Consequences of the modified Th2-like responses on co-infection, vaccination, and inflammatory diseases are discussed. PMID:20150967

De novo assembly and characterization of the transcriptome of the parasitic weed dodder identifies genes associated with plant parasitism.

PubMed

Ranjan, Aashish; Ichihashi, Yasunori; Farhi, Moran; Zumstein, Kristina; Townsley, Brad; David-Schwartz, Rakefet; Sinha, Neelima R

2014-11-01

Parasitic flowering plants are one of the most destructive agricultural pests and have major impact on crop yields throughout the world. Being dependent on finding a host plant for growth, parasitic plants penetrate their host using specialized organs called haustoria. Haustoria establish vascular connections with the host, which enable the parasite to steal nutrients and water. The underlying molecular and developmental basis of parasitism by plants is largely unknown. In order to investigate the process of parasitism, RNAs from different stages (i.e. seed, seedling, vegetative strand, prehaustoria, haustoria, and flower) were used to de novo assemble and annotate the transcriptome of the obligate plant stem parasite dodder (Cuscuta pentagona). The assembled transcriptome was used to dissect transcriptional dynamics during dodder development and parasitism and identified key gene categories involved in the process of plant parasitism. Host plant infection is accompanied by increased expression of parasite genes underlying transport and transporter categories, response to stress and stimuli, as well as genes encoding enzymes involved in cell wall modifications. By contrast, expression of photosynthetic genes is decreased in the dodder infective stages compared with normal stem. In addition, genes relating to biosynthesis, transport, and response of phytohormones, such as auxin, gibberellins, and strigolactone, were differentially expressed in the dodder infective stages compared with stems and seedlings. This analysis sheds light on the transcriptional changes that accompany plant parasitism and will aid in identifying potential gene targets for use in controlling the infestation of crops by parasitic weeds. © 2014 American Society of Plant Biologists. All Rights Reserved.

De Novo Assembly and Characterization of the Transcriptome of the Parasitic Weed Dodder Identifies Genes Associated with Plant Parasitism1[C][W][OPEN

PubMed Central

Ranjan, Aashish; Ichihashi, Yasunori; Farhi, Moran; Zumstein, Kristina; Townsley, Brad; David-Schwartz, Rakefet; Sinha, Neelima R.

2014-01-01

Parasitic flowering plants are one of the most destructive agricultural pests and have major impact on crop yields throughout the world. Being dependent on finding a host plant for growth, parasitic plants penetrate their host using specialized organs called haustoria. Haustoria establish vascular connections with the host, which enable the parasite to steal nutrients and water. The underlying molecular and developmental basis of parasitism by plants is largely unknown. In order to investigate the process of parasitism, RNAs from different stages (i.e. seed, seedling, vegetative strand, prehaustoria, haustoria, and flower) were used to de novo assemble and annotate the transcriptome of the obligate plant stem parasite dodder (Cuscuta pentagona). The assembled transcriptome was used to dissect transcriptional dynamics during dodder development and parasitism and identified key gene categories involved in the process of plant parasitism. Host plant infection is accompanied by increased expression of parasite genes underlying transport and transporter categories, response to stress and stimuli, as well as genes encoding enzymes involved in cell wall modifications. By contrast, expression of photosynthetic genes is decreased in the dodder infective stages compared with normal stem. In addition, genes relating to biosynthesis, transport, and response of phytohormones, such as auxin, gibberellins, and strigolactone, were differentially expressed in the dodder infective stages compared with stems and seedlings. This analysis sheds light on the transcriptional changes that accompany plant parasitism and will aid in identifying potential gene targets for use in controlling the infestation of crops by parasitic weeds. PMID:24399359

Host-Parasite-Bacteria Triangle: The Microbiome of the Parasitic Weed Phelipanche aegyptiaca and Tomato-Solanum lycopersicum (Mill.) as a Host

PubMed Central

Iasur Kruh, Lilach; Lahav, Tamar; Abu-Nassar, Jacline; Achdari, Guy; Salami, Raghda; Freilich, Shiri; Aly, Radi

2017-01-01

Broomrapes (Phelipanche/Orobanche spp.) are holoparasitic plants that subsist on the roots of a variety of agricultural crops, establishing direct connections with the host vascular system. This connection allows for the exchange of various substances and a possible exchange of endophytic microorganisms that inhabit the internal tissues of both plants. To shed some light on bacterial interactions occurring between the parasitic Phelipanche aegyptiaca and its host tomato, we characterized the endophytic composition in the parasite during the parasitization process and ascertained if these changes were accompanied by changes to endophytes in the host root. Endophyte communities of the parasitic weed were significantly different from that of the non-parasitized tomato root but no significant differences were observed between the parasite and its host after parasitization, suggesting the occurrence of bacterial exchange between these two plants. Moreover, the P. aegyptiaca endophytic community composition showed a clear shift from gram negative to gram-positive bacteria at different developmental stages of the parasite life cycle. To examine possible functions of the endophytic bacteria in both the host and the parasite plants, a number of unique bacterial candidates were isolated and characterized. Results showed that a Pseudomonas strain PhelS10, originating from the tomato roots, suppressed approximately 80% of P. aegyptiaca seed germination and significantly reduced P. aegyptiaca parasitism. The information gleaned in the present study regarding the endophytic microbial communities in this unique ecological system of two plants connected by their vascular system, highlights the potential of exploiting alternative environmentally friendly approaches for parasitic weed control. PMID:28298918

Parasite biodiversity and its determinants in coastal marine teleost fishes of Brazil.

PubMed

Luque, J L; Mouillot, D; Poulin, R

2004-06-01

Recent studies of the forces behind the diversification of parasite assemblages have shed light on many aspects of parasite biodiversity. By using only parasite species richness as their measure of diversity, however, previous investigations have ignored the relatedness among parasite species and the taxonomic structure of the assemblages, which contain much information about their evolutionary origins. Here, we performed a comparative analysis across 50 species of fish from the coast of Brazil; we evaluated the effects of several host traits (body size, social behaviour, feeding habits, preference for benthic vs. pelagic habitats, depth range, and ability to enter brackish waters) on the diversity of their assemblages of metazoan parasites. As measures of diversity, we used parasite species richness, as well as the average taxonomic distinctness of the assemblage and its variance; the latter measures are based on the average taxonomic distance between any two parasite species in an assemblage. Unlike parasite species richness, taxonomic distinctness was unaffected by the number of host individuals examined per species. Fish body length proved to be the main predictor of parasite species richness, even when controlling for the confounding influences of host phylogeny and sampling effort, although it did not correlate with measures of parasite taxonomic distinctness. Predatory fish also had higher parasite species richness than planktivores, but this trend could not be confirmed using phylogenetically independent contrasts between host taxa. The main host feature associated with the taxonomic diversity of parasites was schooling behaviour, with schooling fish having more taxonomically diverse parasite assemblages than those of their non-schooling relatives. When focusing on endoparasite species only, both predatory feeding habits and a broad depth range were associated with the taxonomic distinctness of parasites. Our results suggest that certain host traits (i.e. body size) determine how many parasite species a host can accumulate over evolutionary time, whereas different host features influence the processes causing the taxonomic diversification of parasite assemblages.

Medicinal plants used to control internal and external parasites in goats.

PubMed

Sanhokwe, Marcia; Mupangwa, Johnfisher; Masika, Patrick J; Maphosa, Viola; Muchenje, Voster

2016-04-29

The use of medicinal plants plays a major role in the primary health care of animals in South Africa. A survey was conducted to document medicinal plants used to control parasites in goats in Kwezi and Ntambethemba villages in the Eastern Cape Province, South Africa. Information from 50 farmers and 3 herbalists was obtained through the use of a structured questionnaire, and a snowball sampling technique was used to identify key informants. The obtained data were analysed using PROC FREQ of SAS (2003), and fidelity level values were determined to estimate the healing potential of the mentioned plants. The survey revealed nine plant species belonging to eight families that were used to control parasites in goats. Asphodelaceae (22.22%) was the most frequently used plant family. Leaves were the most used plant parts, constituting 60.38%. They were prepared either as infusions or decoctions of single plants or in mixtures. Aloe ferox, Acokanthera oppositifolia and Elephantorrhiza elephantina were the plants having the highest fidelity level for their use to control parasites, each scoring 100%, followed by Albuca setosa (83.33%). The study revealed low knowledge about ethnoveterinary medicine in the study area. It also revealed that information on ethno-veterinary medicine in this area is mostly confined to older people and there is danger that this knowledge can be lost before being passed on to other generations. Therefore, there is an urgent need to document information on these plant species so that the future generation can benefit. Further investigation should be carried out to validate the efficacy and safety of the above-mentioned plants so as to provide cheap alternative ways of controlling parasites.

New directions in Guatemala.

PubMed

1997-02-01

This news brief relates some new directions, since its inception in 1988, which the Family Welfare Association of Guatemala (APROFAM) will be undertaking during 1996-97. In December 1997, APROFAM restructured its program to include reproductive health services with family planning services. The program will target rural Mayan communities. The program will be working toward service sustainability, due to reduced external support. In October 1996 a new board was established that will focus on marketing, IEC, finance and administration, rural development, and clinical services. Meetings between the new board of directors of APROFAM and JOICFP focused on the use of integrated programs as a model for widespread programming among the rural Mayan population. The integrated program that was implemented by JOICFP was successful in reaching Mayan communities of Solola. This population was difficult to reach with conventional family planning approaches. The integrated program was successful in establishing trust with and participation of the rural Mayans. Activities such as parasite control, skills training, and income generation for women were useful in establishing trust and promoting self-reliance. Integrated programs will refocus on family planning and developing self-reliance. The UNFPA will be conducting an annual internal evaluation as a means of sharing information and deepening understanding of project implementation.

Identification of candidate transmission-blocking antigen genes in Theileria annulata and related vector-borne apicomplexan parasites.

PubMed

Lempereur, Laetitia; Larcombe, Stephen D; Durrani, Zeeshan; Karagenc, Tulin; Bilgic, Huseyin Bilgin; Bakirci, Serkan; Hacilarlioglu, Selin; Kinnaird, Jane; Thompson, Joanne; Weir, William; Shiels, Brian

2017-06-05

Vector-borne apicomplexan parasites are a major cause of mortality and morbidity to humans and livestock globally. The most important disease syndromes caused by these parasites are malaria, babesiosis and theileriosis. Strategies for control often target parasite stages in the mammalian host that cause disease, but this can result in reservoir infections that promote pathogen transmission and generate economic loss. Optimal control strategies should protect against clinical disease, block transmission and be applicable across related genera of parasites. We have used bioinformatics and transcriptomics to screen for transmission-blocking candidate antigens in the tick-borne apicomplexan parasite, Theileria annulata. A number of candidate antigen genes were identified which encoded amino acid domains that are conserved across vector-borne Apicomplexa (Babesia, Plasmodium and Theileria), including the Pfs48/45 6-cys domain and a novel cysteine-rich domain. Expression profiling confirmed that selected candidate genes are expressed by life cycle stages within infected ticks. Additionally, putative B cell epitopes were identified in the T. annulata gene sequences encoding the 6-cys and cysteine rich domains, in a gene encoding a putative papain-family cysteine peptidase, with similarity to the Plasmodium SERA family, and the gene encoding the T. annulata major merozoite/piroplasm surface antigen, Tams1. Candidate genes were identified that encode proteins with similarity to known transmission blocking candidates in related parasites, while one is a novel candidate conserved across vector-borne apicomplexans and has a potential role in the sexual phase of the life cycle. The results indicate that a 'One Health' approach could be utilised to develop a transmission-blocking strategy effective against vector-borne apicomplexan parasites of animals and humans.

The biological and practical significance of antigenic variability in protective T cell responses against Theileria parva.

PubMed

Morrison, W I

2007-08-19

The evolution of antigenically distinct pathogen strains that fail to cross-protect is well documented for pathogens controlled primarily by humoral immune responses. Unlike antibodies, which recognise native proteins, protective T cells can potentially recognise epitopes in a variety of proteins that are not necessarily displayed on the pathogen surface. Moreover, individual hosts of different MHC genotypes generally respond to different sets of epitopes. It is therefore less easy to envisage how strain restricted immunity can arise for pathogens controlled by T cell responses, particularly in antigenically complex parasites. Nevertheless, strain restricted immunity is clearly a feature of a number of parasitic infections, where immunity is known to be mediated by T cell responses. One such parasite is Theileria parva which induces potent CD8 T cell responses that play an important role in immunity. CD8 T cells specific for parasitized lymphoblasts exhibit strain specificity, which appears to correlate with the ability of parasite strains to cross-protect. Studies using recently identified T. parva antigens recognised by CD8 T cells have shown that the strain restricted nature of immunity is a consequence of the CD8 T cell response in individual animals being focused on a limited number of dominant polymorphic antigenic determinants. Responses in animals of different MHC genotypes are often directed to different parasite antigens, indicating that, at the host population level, a larger number of parasite proteins can serve as targets for the protective T cell response. Nevertheless, the finding that parasite strains show overlapping antigenic profiles, probably as a consequence of sexual recombination, suggests that induction of responses to an extended but limited set of antigens in individual animals may overcome the strain restricted nature of immunity.

A brief history and overview of Toxoplasma gondii.

PubMed

Innes, E A

2010-02-01

Toxoplasma gondii was discovered by scientists working in North Africa and Brazil around 100 years ago. The parasite has since been found to be capable of infecting all warm-blooded animals including humans making it one of the most successful parasitic organisms worldwide. The pathogenic potential of T. gondii was recognized in the 1920s and 1930s, in congenitally infected children presenting with the classic triad of symptoms, namely hydrocephalus, retinochoroiditis and encephalitis. In addition, around the same time T. gondii parasites were found to be associated with severe intraocular inflammation. In the 1980s, T. gondii emerged as a major cause of death in patients with acquired immunodeficiency syndrome, illustrating the importance of the immune system in controlling T. gondii infection. T. gondii was reported as a major cause of abortion in sheep in New Zealand in the 1950s, which raised questions about potential new transmission routes for the parasite. The discovery of the cat as the definitive host in the 1960s was a very important finding as it helped to complete our understanding of the parasite's life cycle, and the oocyst stage of T. gondii shed in the faeces of infected cats was found to be an important source of infection for many intermediate hosts and helped to explain infection in herbivorous animals and people with a vegetarian diet. In addition, this stage of the parasite was very robust and could survive in the environment, depending on the climatic conditions, for up to 12-18 months. Knowledge of the parasite's life cycle, transmission routes, risk groups and host immune responses has helped in the development of strategies to control the disease, reduce transmission of the parasite and limit environmental contamination.

Discovery of genomic intervals that underlie nematode responses to benzimidazoles.

PubMed

Zamanian, Mostafa; Cook, Daniel E; Zdraljevic, Stefan; Brady, Shannon C; Lee, Daehan; Lee, Junho; Andersen, Erik C

2018-03-01

Parasitic nematodes impose a debilitating health and economic burden across much of the world. Nematode resistance to anthelmintic drugs threatens parasite control efforts in both human and veterinary medicine. Despite this threat, the genetic landscape of potential resistance mechanisms to these critical drugs remains largely unexplored. Here, we exploit natural variation in the model nematodes Caenorhabditis elegans and Caenorhabditis briggsae to discover quantitative trait loci (QTL) that control sensitivity to benzimidazoles widely used in human and animal medicine. High-throughput phenotyping of albendazole, fenbendazole, mebendazole, and thiabendazole responses in panels of recombinant lines led to the discovery of over 15 QTL in C. elegans and four QTL in C. briggsae associated with divergent responses to these anthelmintics. Many of these QTL are conserved across benzimidazole derivatives, but others show drug and dose specificity. We used near-isogenic lines to recapitulate and narrow the C. elegans albendazole QTL of largest effect and identified candidate variants correlated with the resistance phenotype. These QTL do not overlap with known benzimidazole target resistance genes from parasitic nematodes and present specific new leads for the discovery of novel mechanisms of nematode benzimidazole resistance. Analyses of orthologous genes reveal conservation of candidate benzimidazole resistance genes in medically important parasitic nematodes. These data provide a basis for extending these approaches to other anthelmintic drug classes and a pathway towards validating new markers for anthelmintic resistance that can be deployed to improve parasite disease control.

Oestradiol and progesterone differentially alter cytoskeletal protein expression and flame cell morphology in Taenia crassiceps.

PubMed

Ambrosio, Javier R; Ostoa-Saloma, Pedro; Palacios-Arreola, M Isabel; Ruíz-Rosado, Azucena; Sánchez-Orellana, Pedro L; Reynoso-Ducoing, Olivia; Nava-Castro, Karen E; Martínez-Velázquez, Nancy; Escobedo, Galileo; Ibarra-Coronado, Elizabeth G; Valverde-Islas, Laura; Morales-Montor, Jorge

2014-09-01

We examined the effects of oestradiol (E2) and progesterone (P4) on cytoskeletal protein expression in the helminth Taenia crassiceps - specifically actin, tubulin and myosin. These proteins assemble into flame cells, which constitute the parasite excretory system. Total protein extracts were obtained from E2- and P4-treated T. crassiceps cysticerci and untreated controls, and analysed by one- and two-dimensional protein electrophoresis, flow cytometry, immunofluorescence and videomicroscopy. Exposure of T. crassiceps cysticerci to E2 and P4 induced differential protein expression patterns compared with untreated controls. Changes in actin, tubulin and myosin expression were confirmed by flow cytometry of parasite cells and immunofluorescence. In addition, parasite morphology was altered in response to E2 and P4 versus controls. Flame cells were primarily affected at the level of the ciliary tuft, in association with the changes in actin, tubulin and myosin. We conclude that oestradiol and progesterone act directly on T. crassiceps cysticerci, altering actin, tubulin and myosin expression and thus affecting the assembly and function of flame cells. Our results increase our understanding of several aspects of the molecular crosstalk between host and parasite, which might be useful in designing anthelmintic drugs that exclusively impair parasitic proteins which mediate cell signaling and pathogenic reproduction and establishment. Copyright © 2014 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

New clinical and experimental insights into Old World and neotropical ocular toxoplasmosis.

PubMed

Pfaff, Alexander W; de-la-Torre, Alejandra; Rochet, Elise; Brunet, Julie; Sabou, Marcela; Sauer, Arnaud; Bourcier, Tristan; Gomez-Marin, Jorge E; Candolfi, Ermanno

2014-02-01

Retinal lesions or other ocular manifestations are serious consequences of infection with the protozoan parasite Toxoplasma gondii. Whilst classically considered a consequence of congenital transmission, recent screening studies estimated that 2% of T. gondii seropositive persons in Europe and North America have retinal lesions, most of them persisting unnoticed. The situation is more dramatic in South America, probably due to the predominance of virulent strains. Some of these strains seem to exhibit ocular or neuronal tropism and are responsible for severe ocular lesions. Despite the medical importance, the physiopathological mechanisms have only recently begun to be elucidated. The particular immune-privileged situation in the eye has to be considered. Studies on French patients showed low or undetectable ocular parasite loads, but a clear Th1/Th17 type immune reaction. Suitable mouse models have appeared in the last few years. Using such a model, IL-17A proved to impair parasite control and induce pathology. In contrast, in South American patients, the parasite seems to be much less efficiently controlled through a Th2 type or suppressive immune response that favors parasite replication. Finally, several host genetic markers controlling immune response factors have been associated with ocular involvement of T. gondii infection, mainly in South America. Copyright © 2013 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

Potential chemotherapeutic targets in the purine metabolism of parasites.

PubMed

el Kouni, Mahmoud H

2003-09-01

Parasites are responsible for a wide variety of infectious diseases in human as well as in domestic and wild animals, causing an enormous health and economical blight. Current containment strategies are not entirely successful and parasitic infections are on the rise. In the absence of availability of antiparasitic vaccines, chemotherapy remains the mainstay for the treatment of most parasitic diseases. However, there is an urgent need for new drugs to prevent or combat some major parasitic infections because of lack of a single effective approach for controlling the parasites (e.g., trypanosomiasis) or because some serious parasitic infections developed resistance to presently available drugs (e.g., malaria). The rational design of a drug is usually based on biochemical and physiological differences between pathogens and host. Some of the most striking differences between parasites and their mammalian host are found in purine metabolism. Purine nucleotides can be synthesized by the de novo and/or the so-called "salvage" pathways. Unlike their mammalian host, most parasites studied lack the pathways for de novo purine biosynthesis and rely on the salvage pathways to meet their purine demands. Moreover, because of the great phylogenic separation between the host and the parasite, there are in some cases sufficient distinctions between corresponding enzymes of the purine salvage from the host and the parasite that can be exploited to design specific inhibitors or "subversive substrates" for the parasitic enzymes. Furthermore, the specificities of purine transport, the first step in purine salvage, diverge significantly between parasites and their mammalian host. This review highlights the unique transporters and enzymes responsible for the salvage of purines in parasites that could constitute excellent potential targets for the design of safe and effective antiparasitic drugs.

Efficacy of killed whole-parasite vaccines in the prevention of leishmaniasis: a meta-analysis.

PubMed

Noazin, Sassan; Khamesipour, Ali; Moulton, Lawrence H; Tanner, Marcel; Nasseri, Kiumarss; Modabber, Farrokh; Sharifi, Iraj; Khalil, E A G; Bernal, Ivan Dario Velez; Antunes, Carlos M F; Smith, Peter G

2009-07-30

Despite decades of investigation in countries on three continents, an efficacious vaccine against Leishmania infections has not been developed. Although some indication of protection was observed in some of the controlled trials conducted with "first-generation" whole, inactivated Leishmania parasite vaccines, convincing evidence of protection was lacking. After reviewing all previously published or unpublished randomized, controlled field efficacy clinical trials of prophylactic candidate vaccines, a meta-analysis of qualified trials was conducted to evaluate whether there was some evidence of protection revealed by considering the results of all trials together. The findings indicate that the whole-parasite vaccine candidates tested do not confer significant protection against human leishmaniasis.

Keeping the herds healthy and alert: Implications of predator control for infectious disease

USGS Publications Warehouse

Packer, Craig; Holt, Robert D.; Hudson, Peter J.; Lafferty, Kevin D.; Dobson, Andrew P.

2003-01-01

Predator control programmes are generally implemented in an attempt to increase prey population sizes. However, predator removal could prove harmful to prey populations that are regulated primarily by parasitic infections rather than by predation. We develop models for microparasitic and macroparasitic infection that specify the conditions where predator removal will (a) increase the incidence of parasitic infection, (b) reduce the number of healthy individuals in the prey population and (c) decrease the overall size of the prey population. In general, predator removal is more likely to be harmful when the parasite is highly virulent, macroparasites are highly aggregated in their prey, hosts are long-lived and the predators select infected prey.

Demonstration of relaxed static stability on a commercial transport

NASA Technical Reports Server (NTRS)

Rising, J. J.; Davis, W. J.; Willey, C. S.; Cokeley, R. C.

1984-01-01

Increasing jet aircraft fuel costs from 25 percent to nearly 60 percent of the aircraft direct operating costs have led to a heavy emphasis on the development of transport aircraft with significantly improved aerodynamic performance. The application of the concept of relaxed static stability (RSS) and the utilization of an active control stability augmentation system make it possible to design an aircraft with reduced aerodynamic trim drag due to a farther-aft cg balance. Reduced aerodynamic parasite drag and lower structural weight due to a smaller horizontal tail surface can also be obtained. The application of RSS has been studied under a NASA-sponsored program to determine ways of improving the energy efficiency in current and future transport aircraft. Attention is given to a near-term pitch active control system, an advanced pitch active control system, and an operational overview.

Using the Very Large Array (VLA) and other radio telescopes to perform a parasitic Search for Extraterrestrial Intelligence (SETI)

NASA Technical Reports Server (NTRS)

Tarter, J.

1985-01-01

This paper describes several attempts to utilize various radio telescopes in a manner that we term "parasitic," that is in a manner that does not interrupt or seriously impact the standard astronomical observing programs in progress at the radio observatories. In the extreme case, only recorded astronomical data are accessed off-line, after the fact, without any burden on the observatory at all.

Using the Very Large Array (VLA) and other radio telescopes to perform a parasitic search for extraterrestrial intelligence (SETI)

NASA Technical Reports Server (NTRS)

Tarter, J. C.

1984-01-01

This paper describes several attempts to utilize various radio telescopes in a manner that is termed 'parasitic', that is in a manner that does not interrupt or seriously impact the standard astronomical observing programs in progress at the radio observatories. In the extreme case, only recorded astronomical data are accessed off-line, after the fact, without any burden on the observatory at all.

Using the Very Large Array (VLA) and other radio telescopes to perform a parasitic Search for Extraterrestrial Intelligence (SETI).

PubMed

Tarter, J

1985-01-01

This paper describes several attempts to utilize various radio telescopes in a manner that we term "parasitic," that is in a manner that does not interrupt or seriously impact the standard astronomical observing programs in progress at the radio observatories. In the extreme case, only recorded astronomical data are accessed off-line, after the fact, without any burden on the observatory at all.

Perspectives in the control of infectious diseases by transgenic mosquitoes in the post-genomic era--a review.

PubMed

Sperança, Márcia Aparecida; Capurro, Margareth Lara

2007-06-01

Arthropod-borne diseases caused by a variety of microorganisms such as dengue virus and malaria parasites afflict billions of people worldwide imposing major economic and social burdens. Despite many efforts, vaccines against diseases transmitted by mosquitoes, with the exception of yellow fever, are not available. Control of such infectious pathogens is mainly performed by vector management and treatment of affected individuals with drugs. However, the numbers of insecticide-resistant insects and drug-resistant parasites are increasing. Therefore, inspired in recent years by a lot of new data produced by genomics and post-genomics research, several scientific groups have been working on different strategies to control infectious arthropod-borne diseases. This review focuses on recent advances and perspectives towards construction of transgenic mosquitoes refractory to malaria parasites and dengue virus transmission.

Targeted Screening Strategies to Detect Trypanosoma cruzi Infection in Children

PubMed Central

Levy, Michael Z.; Kawai, Vivian; Bowman, Natalie M.; Waller, Lance A.; Cabrera, Lilia; Pinedo-Cancino, Viviana V.; Seitz, Amy E.; Steurer, Frank J.; Cornejo del Carpio, Juan G.; Cordova-Benzaquen, Eleazar; Maguire, James H.; Gilman, Robert H.; Bern, Caryn

2007-01-01

Background Millions of people are infected with Trypanosoma cruzi, the causative agent of Chagas disease in Latin America. Anti-trypanosomal drug therapy can cure infected individuals, but treatment efficacy is highest early in infection. Vector control campaigns disrupt transmission of T. cruzi, but without timely diagnosis, children infected prior to vector control often miss the window of opportunity for effective chemotherapy. Methods and Findings We performed a serological survey in children 2–18 years old living in a peri-urban community of Arequipa, Peru, and linked the results to entomologic, spatial and census data gathered during a vector control campaign. 23 of 433 (5.3% [95% CI 3.4–7.9]) children were confirmed seropositive for T. cruzi infection by two methods. Spatial analysis revealed that households with infected children were very tightly clustered within looser clusters of households with parasite-infected vectors. Bayesian hierarchical mixed models, which controlled for clustering of infection, showed that a child's risk of being seropositive increased by 20% per year of age and 4% per vector captured within the child's house. Receiver operator characteristic (ROC) plots of best-fit models suggest that more than 83% of infected children could be identified while testing only 22% of eligible children. Conclusions We found evidence of spatially-focal vector-borne T. cruzi transmission in peri-urban Arequipa. Ongoing vector control campaigns, in addition to preventing further parasite transmission, facilitate the collection of data essential to identifying children at high risk of T. cruzi infection. Targeted screening strategies could make integration of diagnosis and treatment of children into Chagas disease control programs feasible in lower-resource settings. PMID:18160979

Development and implementation of an integrated program for control of sea lampreys in the St. Marys River

USGS Publications Warehouse

Schleen, Larry P.; Christie, Gavin C.; Heinrich, John W.; Bergstedt, Roger A.; Young, Robert J.; Morse, Terry J.; Lavis, Dennis S.; Bills, Terry D.; Johnson, James E.; Ebener, Mark P.

2003-01-01

The development and implementation of a strategy for control of sea lampreys (Petromyzon marinus) in the St. Marys River formed the basis for rehabilitation of lake trout (Salvelinus namaycush) and other fish in Lakes Huron and Michigan. The control strategy was implemented by the Great Lakes Fishery Commission (GLFC) upon recommendations by the interagency Sea Lamprey Integration Committee, and many managers and scientists from United States and Canada federal, state, provincial, tribal, and private institutions. Analyses of benefits vs. costs of control options and modeling of the cumulative effects on abundance of parasitic-phase sea lampreys and lake trout produced a strategy that involved an integration of control technologies that included long- and short-term measures. The longterm measures included interference with sea lamprey reproduction by the trapping and removal of spawning-phase sea lampreys from the river and the sterilization and release of the trapped male sea lampreys. The theoretical reduction of larvae produced in the river from these two combined techniques averaged almost 90% during 1997 to 1999. Lampricide treatment with granular Bayluscide of 880 ha of plots densely populated with larvae occurred during 1998, 1999, and 2001 because modeling showed the sooner parasitic-phase sea lamprey populations declined in Lake Huron the greater the improvement for restoration of lake trout during 1995 to 2015. Post-treatment assessments showed about 55% of the larvae had been removed from the river. An adaptive assessment plan predicted high probability of detection of control effects because of many available indicators. The GLFC will face several critical decisions beyond 2001, and initiated a decision analysis project to aid in those decisions.

Msp40 effector of root-knot nematode manipulates plant immunity to facilitate parasitism

PubMed Central

Niu, Junhai; Liu, Pei; Liu, Qian; Chen, Changlong; Guo, Quanxin; Yin, Junmei; Yang, Guangsui; Jian, Heng

2016-01-01

Root-knot nematodes (RKNs) are obligate biotrophic parasites that invade plant roots and engage in prolonged and intimate relationships with their hosts. Nematode secretions, some of which have immunosuppressing activity, play essential roles in successful parasitism; however, their mechanisms of action remain largely unknown. Here, we show that the RKN-specific gene MiMsp40, cloned from Meloidogyne incognita, is expressed exclusively in subventral oesophageal gland cells and is strongly upregulated during early parasitic stages. Arabidopsis plants overexpressing MiMsp40 were more susceptible to nematode infection than were wild type plants. Conversely, the host-derived MiMsp40 RNAi suppressed nematode parasitism and/or reproduction. Moreover, overexpression of MiMsp40 in plants suppressed the deposition of callose and the expression of marker genes for bacterial elicitor elf18-triggered immunity. Transient expression of MiMsp40 prevented Bax-triggered defence-related programmed cell death. Co-agroinfiltration assays indicated that MiMsp40 also suppressed macroscopic cell death triggered by MAPK cascades or by the ETI cognate elicitors R3a/Avr3a. Together, these results demonstrate that MiMsp40 is a novel Meloidogyne-specific effector that is injected into plant cells by early parasitic stages of the nematode and that plays a role in suppressing PTI and/or ETI signals to facilitate RKN parasitism. PMID:26797310

Discovery of quantitative trait loci for resistance to parasitic nematode infection in sheep: I. Analysis of outcross pedigrees

PubMed Central

Crawford, Allan M; Paterson, Korena A; Dodds, Ken G; Diez Tascon, Cristina; Williamson, Penny A; Roberts Thomson, Meredith; Bisset, Stewart A; Beattie, Anne E; Greer, Gordon J; Green, Richard S; Wheeler, Roger; Shaw, Richard J; Knowler, Kevin; McEwan, John C

2006-01-01

Background Currently most pastoral farmers rely on anthelmintic drenches to control gastrointestinal parasitic nematodes in sheep. Resistance to anthelmintics is rapidly increasing in nematode populations such that on some farms none of the drench families are now completely effective. It is well established that host resistance to nematode infection is a moderately heritable trait. This study was undertaken to identify regions of the genome, quantitative trait loci (QTL) that contain genes affecting resistance to parasitic nematodes. Results Rams obtained from crossing nematode parasite resistant and susceptible selection lines were used to derive five large half-sib families comprising between 348 and 101 offspring per sire. Total offspring comprised 940 lambs. Extensive measurements for a range of parasite burden and immune function traits in all offspring allowed each lamb in each pedigree to be ranked for relative resistance to nematode parasites. Initially the 22 most resistant and 22 most susceptible progeny from each pedigree were used in a genome scan that used 203 microsatellite markers spread across all sheep autosomes. This study identified 9 chromosomes with regions showing sufficient linkage to warrant the genotyping of all offspring. After genotyping all offspring with markers covering Chromosomes 1, 3, 4, 5, 8, 12, 13, 22 and 23, the telomeric end of chromosome 8 was identified as having a significant QTL for parasite resistance as measured by the number of Trichostrongylus spp. adults in the abomasum and small intestine at the end of the second parasite challenge. Two further QTL for associated immune function traits of total serum IgE and T. colubiformis specific serum IgG, at the end of the second parasite challenge, were identified on chromosome 23. Conclusion Despite parasite resistance being a moderately heritable trait, this large study was able to identify only a single significant QTL associated with it. The QTL concerned adult parasite burdens at the end of the second parasite challenge when the lambs were approximately 6 months old. Our failure to discover more QTL suggests that most of the genes controlling this trait are of relatively small effect. The large number of suggestive QTL discovered (more than one per family per trait than would be expected by chance) also supports this conclusion. PMID:16846521

Multihost Bartonella parasites display covert host specificity even when transmitted by generalist vectors.

PubMed

Withenshaw, Susan M; Devevey, Godefroy; Pedersen, Amy B; Fenton, Andy

2016-11-01

Many parasites infect multiple sympatric host species, and there is a general assumption that parasite transmission between co-occurring host species is commonplace. Such between-species transmission could be key to parasite persistence within a disease reservoir and is consequently an emerging focus for disease control. However, while a growing body of theory indicates the potential importance of between-species transmission for parasite persistence, conclusive empirical evidence from natural communities is lacking, and the assumption that between-species transmission is inevitable may therefore be wrong. We investigated the occurrence of between-species transmission in a well-studied multihost parasite system. We identified the flea-borne Bartonella parasites infecting sympatric populations of Apodemus sylvaticus (wood mice) and Myodes glareolus (bank voles) in the UK and confirmed that several Bartonella species infect both rodent species. However, counter to previous knowledge, genetic characterization of these parasites revealed covert host specificity, where each host species is associated with a distinct assemblage of genetic variants, indicating that between-species transmission is rare. Limited between-species transmission could result from rare encounters between one host species and the parasites infecting another and/or host-parasite incompatibility. We investigated the occurrence of such encounter and compatibility barriers by identifying the flea species associated with each rodent host, and the Bartonella variants carried by individual fleas. We found that the majority of fleas were host-generalists but the assemblage of Bartonella variants in fleas tended to reflect the assemblage of Bartonella variants in the host species they were collected from, thus providing evidence of encounter barriers mediated by limited between-species flea transfer. However, we also found several fleas that were carrying variants never found in the host species from which they were collected, indicating some degree of host-pathogen incompatibility when barriers to encounter are overcome. Overall, these findings challenge our default perceptions of multihost parasite persistence, as they show that despite considerable overlaps in host species ecology, separate populations of the same parasite species may circulate and persist independently in different sympatric host species. This questions our fundamental understanding of endemic transmission dynamics and the control of infection within natural reservoir communities. © 2016 The Authors. Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.

Discovery of quantitative trait loci for resistance to parasitic nematode infection in sheep: I. Analysis of outcross pedigrees.

PubMed

Crawford, Allan M; Paterson, Korena A; Dodds, Ken G; Diez Tascon, Cristina; Williamson, Penny A; Roberts Thomson, Meredith; Bisset, Stewart A; Beattie, Anne E; Greer, Gordon J; Green, Richard S; Wheeler, Roger; Shaw, Richard J; Knowler, Kevin; McEwan, John C

2006-07-18

Currently most pastoral farmers rely on anthelmintic drenches to control gastrointestinal parasitic nematodes in sheep. Resistance to anthelmintics is rapidly increasing in nematode populations such that on some farms none of the drench families are now completely effective. It is well established that host resistance to nematode infection is a moderately heritable trait. This study was undertaken to identify regions of the genome, quantitative trait loci (QTL) that contain genes affecting resistance to parasitic nematodes. Rams obtained from crossing nematode parasite resistant and susceptible selection lines were used to derive five large half-sib families comprising between 348 and 101 offspring per sire. Total offspring comprised 940 lambs. Extensive measurements for a range of parasite burden and immune function traits in all offspring allowed each lamb in each pedigree to be ranked for relative resistance to nematode parasites. Initially the 22 most resistant and 22 most susceptible progeny from each pedigree were used in a genome scan that used 203 microsatellite markers spread across all sheep autosomes. This study identified 9 chromosomes with regions showing sufficient linkage to warrant the genotyping of all offspring. After genotyping all offspring with markers covering Chromosomes 1, 3, 4, 5, 8, 12, 13, 22 and 23, the telomeric end of chromosome 8 was identified as having a significant QTL for parasite resistance as measured by the number of Trichostrongylus spp. adults in the abomasum and small intestine at the end of the second parasite challenge. Two further QTL for associated immune function traits of total serum IgE and T. colubiformis specific serum IgG, at the end of the second parasite challenge, were identified on chromosome 23. Despite parasite resistance being a moderately heritable trait, this large study was able to identify only a single significant QTL associated with it. The QTL concerned adult parasite burdens at the end of the second parasite challenge when the lambs were approximately 6 months old. Our failure to discover more QTL suggests that most of the genes controlling this trait are of relatively small effect. The large number of suggestive QTL discovered (more than one per family per trait than would be expected by chance) also supports this conclusion.

Malaria prevalence, prevention and treatment seeking practices among nomadic pastoralists in northern Senegal.

PubMed

Seck, Mame Cheikh; Thwing, Julie; Fall, Fatou Ba; Gomis, Jules Francois; Deme, Awa; Ndiaye, Yaye Die; Daniels, Rachel; Volkman, Sarah K; Ndiop, Medoune; Ba, Mady; Ndiaye, Daouda

2017-10-13

Malaria transmission in Senegal is highly stratified, from low in the dry north to moderately high in the moist south. In northern Senegal, along the Senegal River Valley and in the Ferlo semi-desert region, annual incidence is less than five cases per 1000 inhabitants. Many nomadic pastoralists have permanent dwellings in the Ferlo Desert and Senegal River Valley, but spend dry season in the south with their herds, returning north when the rains start, leading to a concern that this population could contribute to ongoing transmission in the north. A modified snowball sampling survey was conducted at six sites in northern Senegal to determine the malaria prevention and treatment seeking practices and parasite prevalence among nomadic pastoralists in the Senegal River Valley and the Ferlo Desert. Nomadic pastoralists aged 6 months and older were surveyed during September and October 2014, and data regarding demographics, access to care and preventive measures were collected. Parasite infection was detected using rapid diagnostic tests (RDTs), microscopy (thin and thick smears) and polymerase chain reaction (PCR). Molecular barcodes were determined by high resolution melting (HRM). Of 1800 participants, 61% were male. Sixty-four percent had at least one bed net in the household, and 53% reported using a net the night before. Only 29% had received a net from a mass distribution campaign. Of the 8% (142) who reported having had fever in the last month, 55% sought care, 20% of whom received a diagnostic test, one-third of which (n = 5) were reported to be positive. Parasite prevalence was 0.44% by thick smear and 0.50% by PCR. None of the molecular barcodes identified among the nomadic pastoralists had been previously identified in Senegal. While access to and utilization of malaria control interventions among nomadic pastoralists was lower than the general population, parasite prevalence was lower than expected and sheds doubt on the perception that they are a source of ongoing transmission in the north. The National Malaria Control Program is making efforts to improve access to malaria prevention and case management for nomadic populations.

Grazing limits natural biological controls of woody encroachment in Inner Mongolia Steppe

PubMed Central

Guo, Hongyu; Guan, Linjing; Wang, Yinhua; Xie, Lina; Prather, Chelse M.; Liu, Chunguang

2017-01-01

ABSTRACT Woody encroachment in grasslands has become increasingly problematic globally. Grazing by domestic animals can facilitate woody encroachment by reducing competition from herbaceous plants and fire frequency. Herbivorous insects and parasitic plants can each exert forces that result in the natural biological control of encroaching woody plants through reducing seeding of their host woody plants. However, the interplay of grazing and dynamics of herbivorous insects or parasitic plants, and its effects on the potential biological control of woody encroachment in grasslands remains unclear. We investigated the flower and pod damage by herbivorous insects, and the infection rates of a parasitic plant on the shrub Caragana microphylla, which is currently encroaching in Inner Mongolia Steppe, under different grazing management treatments (33-year non-grazed, 7-year non-grazed, currently grazed). Our results showed that Caragana biomass was highest at the currently grazed site, and lowest at the 33-year non-grazed site. Herbaceous plant biomass followed the opposite pattern, suggesting that grazing is indeed facilitating the encroachment of Caragana plants in Inner Mongolia Steppe. Grazing also reduced the abundance of herbivorous insects per Caragana flower, numbers of flowers and pods damaged by insect herbivores, and the infection rates of the parasitic plant on Caragana plants. Our results suggest that grazing may facilitate woody encroachment in grasslands not only through canonical mechanisms (e.g. competitive release via feeding on grasses, reductions in fires, etc.), but also by limiting natural biological controls of woody plants (herbivorous insects and parasitic plants). Thus, management efforts must focus on preventing overgrazing to better protect grassland ecosystems from woody encroachment. PMID:28912357

Genomics of apicomplexan parasites.

PubMed

Swapna, Lakshmipuram Seshadri; Parkinson, John

2017-06-01

The increasing prevalence of infections involving intracellular apicomplexan parasites such as Plasmodium, Toxoplasma, and Cryptosporidium (the causative agents of malaria, toxoplasmosis, and cryptosporidiosis, respectively) represent a significant global healthcare burden. Despite their significance, few treatments are available; a situation that is likely to deteriorate with the emergence of new resistant strains of parasites. To lay the foundation for programs of drug discovery and vaccine development, genome sequences for many of these organisms have been generated, together with large-scale expression and proteomic datasets. Comparative analyses of these datasets are beginning to identify the molecular innovations supporting both conserved processes mediating fundamental roles in parasite survival and persistence, as well as lineage-specific adaptations associated with divergent life-cycle strategies. The challenge is how best to exploit these data to derive insights into parasite virulence and identify those genes representing the most amenable targets. In this review, we outline genomic datasets currently available for apicomplexans and discuss biological insights that have emerged as a consequence of their analysis. Of particular interest are systems-based resources, focusing on areas of metabolism and host invasion that are opening up opportunities for discovering new therapeutic targets.

[Progress of research on genetic engineering antibody and its application in prevention and control of parasitic diseases].

PubMed

Yao, Yuan; Yu, Chuan-xin

2013-08-01

Antibody has extensive application prospects in the biomedical field. The inherent disadvantages of traditional polyclonal antibody and monoclonal antibody limit their application values. The humanized and fragmented antibody remodeling has given a rise to a series of genetic engineered antibody variant. This paper reviews the progress of research on genetic engineering antibody and its application in prevention and control of parasitic diseases.

Transfected Babesia bovis Expressing a Tick GST as a Live Vector Vaccine

PubMed Central

Oldiges, Daiane P.; Laughery, Jacob M.; Tagliari, Nelson Junior; Leite Filho, Ronaldo Viana; Davis, William C.; da Silva Vaz, Itabajara; Termignoni, Carlos; Knowles, Donald P.; Suarez, Carlos E.

2016-01-01

The Rhipicephalus microplus tick is a notorious blood-feeding ectoparasite of livestock, especially cattle, responsible for massive losses in animal production. It is the main vector for transmission of pathogenic bacteria and parasites, including Babesia bovis, an intraerythrocytic apicomplexan protozoan parasite responsible for bovine Babesiosis. This study describes the development and testing of a live B. bovis vaccine expressing the protective tick antigen glutathione-S-transferase from Haemaphysalis longicornis (HlGST). The B. bovis S74-T3B parasites were electroporated with a plasmid containing the bidirectional Ef-1α (elongation factor 1 alpha) promoter of B. bovis controlling expression of two independent genes, the selectable marker GFP-BSD (green fluorescent protein–blasticidin deaminase), and HlGST fused to the MSA-1 (merozoite surface antigen 1) signal peptide from B. bovis. Electroporation followed by blasticidin selection resulted in the emergence of a mixed B. bovis transfected line (termed HlGST) in in vitro cultures, containing parasites with distinct patterns of insertion of both exogenous genes, either in or outside the Ef-1α locus. A B. bovis clonal line termed HlGST-Cln expressing intracellular GFP and HlGST in the surface of merozoites was then derived from the mixed parasite line HlGST using a fluorescent activated cell sorter. Two independent calf immunization trials were performed via intravenous inoculation of the HlGST-Cln and a previously described control consisting of an irrelevant transfected clonal line of B. bovis designated GFP-Cln. The control GFP-Cln line contains a copy of the GFP-BSD gene inserted into the Ef-1α locus of B. bovis in an identical fashion as the HIGST-Cln parasites. All animals inoculated with the HlGST-Cln and GFP-Cln transfected parasites developed mild babesiosis. Tick egg fertility and fully engorged female tick weight was reduced significantly in R. microplus feeding on HlGST-Cln-immunized calves. Collectively, these data show the efficacy of a transfected HlGST-Cln B. bovis parasite to induce detectable anti-glutathione-S-transferase antibodies and a reduction in tick size and fecundity of R. microplus feeding in experimentally inoculated animals. PMID:27911903

Biotechnological application of functional genomics towards plant-parasitic nematode control.

PubMed

Li, Jiarui; Todd, Timothy C; Lee, Junghoon; Trick, Harold N

2011-12-01

Plant-parasitic nematodes are primary biotic factors limiting the crop production. Current nematode control strategies include nematicides, crop rotation and resistant cultivars, but each has serious limitations. RNA interference (RNAi) represents a major breakthrough in the application of functional genomics for plant-parasitic nematode control. RNAi-induced suppression of numerous genes essential for nematode development, reproduction or parasitism has been demonstrated, highlighting the considerable potential for using this strategy to control damaging pest populations. In an effort to find more suitable and effective gene targets for silencing, researchers are employing functional genomics methodologies, including genome sequencing and transcriptome profiling. Microarrays have been used for studying the interactions between nematodes and plant roots and to measure both plants and nematodes transcripts. Furthermore, laser capture microdissection has been applied for the precise dissection of nematode feeding sites (syncytia) to allow the study of gene expression specifically in syncytia. In the near future, small RNA sequencing techniques will provide more direct information for elucidating small RNA regulatory mechanisms in plants and specific gene silencing using artificial microRNAs should further improve the potential of targeted gene silencing as a strategy for nematode management. © 2011 The Authors. Plant Biotechnology Journal © 2011 Society for Experimental Biology, Association of Applied Biologists and Blackwell Publishing Ltd.

Assessment and monitoring of onchocerciasis in Latin America.

PubMed

Rodríguez-Pérez, Mario A; Unnasch, Thomas R; Real-Najarro, Olga

2011-01-01

Onchocerciasis has historically been one of the leading causes of infectious blindness worldwide. It is endemic to tropical regions both in Africa and Latin America and in the Yemen. In Latin America, it is found in 13 foci located in 6 different countries. The epidemiologically most important focus of onchocerciasis in the Americas is located in a region spanning the border between Guatemala and Mexico. However, the Amazonian focus straddling the border of Venezuela and Brazil is larger in overall area because the Yanomami populations are scattered over a very large geographical region. Onchocerciasis is caused by infection with the filarial parasite Onchocerca volvulus. The infection is spread through the bites of an insect vector, black flies of the genus Simulium. In Africa, the major vectors are members of the S. damnosum complex, while numerous species serve as vectors of the parasite in Latin America. Latin America has had a long history of attempts to control onchocerciasis, stretching back almost 100 years. The earliest programmes used a strategy of surgical removal of the adult parasites from affected individuals. However, because many of the adult parasites lodge in undetectable and inaccessible areas of the body, the overall effect of this strategy on the prevalence of infection was relatively minor. In 1988, a new drug, ivermectin, was introduced that effectively killed the larval stage (microfilaria) of the parasite in infected humans. As the microfilaria is both the stage that is transmitted by the vector fly and the cause of most of the pathologies associated with the infection, ivermectin opened up a new strategy for the control of onchocerciasis. Concurrent with the use of ivermectin for the treatment of onchocerciasis, a number of sensitive new diagnostic tools were developed (both serological and nucleic acid based) that provided the efficiency, sensitivity and specificity necessary to monitor the decline and eventual elimination of onchocerciasis as a result of successful control. As a result of these advances, a strategy for the elimination of onchocerciasis was developed, based upon mass distribution of ivermectin to afflicted communities for periods lasting long enough to ensure that the parasite population was placed on the road to local elimination. This strategy has been applied for the past decade to the foci in Latin America by a programme overseen by the Onchocerciasis Elimination Program for the Americas (OEPA). The efforts spearheaded by OEPA have been very successful, eliminating ocular disease caused by O. volvulus, and eliminating and interrupting transmission of the parasite in 8 of the 13 foci in the region. As onchocerciasis approaches elimination in Latin America, several questions still need to be addressed. These include defining an acceptable upper limit for transmission in areas in which transmission is thought to have been suppressed (e.g. what is the maximum value for the upper bound of the 95% confidence interval for transmission rates in areas where transmission is no longer detectable), how to develop strategies for conducting surveillance for recrudescence of infection in areas in which transmission is thought to be interrupted and how to address the problem in areas where the mass distribution of ivermectin seems to be unable to completely eliminate the infection. Copyright © 2011 Elsevier Ltd. All rights reserved.

Social transmission of a host defense against cuckoo parasitism.

PubMed

Davies, Nicholas B; Welbergen, Justin A

2009-06-05

Coevolutionary arms races between brood parasites and hosts involve genetic adaptations and counter-adaptations. However, hosts sometimes acquire defenses too rapidly to reflect genetic change. Our field experiments show that observation of cuckoo (Cuculus canorus) mobbing by neighbors on adjacent territories induced reed warblers (Acrocephalus scirpaceus) to increase the mobbing of cuckoos but not of parrots (a harmless control) on their own territory. In contrast, observation of neighbors mobbing parrots had no effect on reed warblers' responses to either cuckoos or parrots. These results indicate that social learning provides a mechanism by which hosts rapidly increase their nest defense against brood parasites. Such enemy-specific social transmission enables hosts to track fine-scale spatiotemporal variation in parasitism and may influence the coevolutionary trajectories and population dynamics of brood parasites and hosts.

Functional genomics approaches in parasitic helminths.

PubMed

Hagen, J; Lee, E F; Fairlie, W D; Kalinna, B H

2012-01-01

As research on parasitic helminths is moving into the post-genomic era, an enormous effort is directed towards deciphering gene function and to achieve gene annotation. The sequences that are available in public databases undoubtedly hold information that can be utilized for new interventions and control but the exploitation of these resources has until recently remained difficult. Only now, with the emergence of methods to genetically manipulate and transform parasitic worms will it be possible to gain a comprehensive understanding of the molecular mechanisms involved in nutrition, metabolism, developmental switches/maturation and interaction with the host immune system. This review focuses on functional genomics approaches in parasitic helminths that are currently used, to highlight potential applications of these technologies in the areas of cell biology, systems biology and immunobiology of parasitic helminths. © 2011 Blackwell Publishing Ltd.

The Babesia bovis hap2 gene is not required for blood stage replication, but expressed upon in vitro sexual stage induction

PubMed Central

Hussein, Hala E.; Bastos, Reginaldo G.; Schneider, David A.; Johnson, Wendell C.; Adham, Fatma K.; Davis, William C.; Laughery, Jacob M.; Herndon, David R.; Alzan, Heba F.

2017-01-01

Babesia bovis, is a tick borne apicomplexan parasite responsible for important cattle losses globally. Babesia parasites have a complex life cycle including asexual replication in the mammalian host and sexual reproduction in the tick vector. Novel control strategies aimed at limiting transmission of the parasite are needed, but transmission blocking vaccine candidates remain undefined. Expression of HAP2 has been recognized as critical for the fertilization of parasites in the Babesia-related Plasmodium, and is a leading candidate for a transmission blocking vaccine against malaria. Hereby we identified the B. bovis hap2 gene and demonstrated that it is widely conserved and differentially transcribed during development within the tick midgut, but not by blood stage parasites. The hap2 gene was disrupted by transfecting B. bovis with a plasmid containing the flanking regions of the hap2 gene and the GPF-BSD gene under the control of the ef-1α-B promoter. Comparison of in vitro growth between a hap2-KO B. bovis clonal line and its parental wild type strain showed that HAP2 is not required for the development of B. bovis in erythrocytes. However, xanthurenic acid-in vitro induction experiments of sexual stages of parasites recovered after tick transmission resulted in surface expression of HAP2 exclusively in sexual stage induced parasites. In addition, hap2-KO parasites were not able to develop such sexual stages as defined both by morphology and by expression of the B. bovis sexual marker genes 6-Cys A and B. Together, the data strongly suggests that tick midgut stage differential expression of hap2 is associated with the development of B. bovis sexual forms. Overall these studies are consistent with a role of HAP2 in tick stages of the parasite and suggest that HAP2 is a potential candidate for a transmission blocking vaccine against bovine babesiosis. PMID:28985216

Correlations Between Emerita analoga and Profilicollis spp. as Influenced by Environmental Factors at Ocean Beach, San Francisco CA

NASA Astrophysics Data System (ADS)

Fang, E.; Le, A.

2014-12-01

Since 2002 the Careers in Science (CiS) intern program has monitored Ocean Beach in San Francisco, California for the population of Emerita analoga (Pacific Mole Crab) as part of a partnership program with the Long-term Monitoring Program and Experiential Training for Students (LiMPETS). LiMPETS is an organization that conducts citizen science with Bay Area youth such as the CiS interns. We specifically assist in the collection of Pacific Mole Crab population statistics at Ocean Beach during the summer from June through August. The purpose of collecting Pacific Mole Crabs is to monitor Profilicollis spp. (Acanthocephalan parasites) - to which Pacific Mole Crabs serve as intermediate hosts - and to learn more about our environment as Pacific Mole Crabs are indicator species. During our collections at Ocean Beach we record size, sex, and number of individuals at specific transects. We then take a random sample from the day, return to the lab, and record their sizes, sexes, and Acanthocephalan parasite load. The results of the collection and dissections are then entered into the LiMPETS online database for scientist and researchers to use. Our project will focus on correlations relating to the data collected (Pacific Mole Crab population, parasite load, abiotic and biotic factors, et cetera).

Correlations Between Emerita analoga and Profilicollis spp. as Influenced by Environmetal Factors at Ocean Beach, San Francisco CA

NASA Astrophysics Data System (ADS)

Wright, S.; Garza, F.; Zhang, P.

2015-12-01

Since 2002 the Careers in Science (CiS) intern program has monitored Ocean Beach in San Francisco, California for the population of Emerita analoga (Pacific Mole Crab) as part of a partnership program with the Long-term Monitoring Program and Experiential Training for Students (LiMPETS). LiMPETS is an organization that conducts citizen science with Bay Area youth such as the CiS interns. We specifically assist in the collection of Pacific Mole Crab population statistics at Ocean Beach during the summer from June through August. The purpose of collecting Pacific Mole Crabs is to monitor Acanthocephalan parasites (Profilicollis spp.) - to which Pacific Mole Crabs serve as intermediate hosts - and to learn more about our environment as Pacific Mole Crabs are indicator species. During our collections at Ocean Beach we record size, sex, and number of individuals at specific transects. We then take a random sample from the day, return to the lab, and record their sizes, sexes, and Acanthocephalan parasite load. The results of the collection and dissections are then entered into the LiMPETS online database for scientist and researchers to use. Our project will focus on correlations relating to the data collected (Pacific Mole Crab population, parasite load, abiotic and biotic factors, et cetera).

Correlations Between Emerita analoga and Profilicollis spp. as Influenced by Environmental Factors at Ocean Beach, San Francisco CA

NASA Astrophysics Data System (ADS)

Ma, J. H.; Hackett, C.; Lucana, F.; Esquivel, A.

2016-12-01

Since 2002 the Careers in Science (CiS) intern program has monitored Ocean Beach in San Francisco, California for the population of Emerita analoga (Pacific Mole Crab) as part of a partnership program with the Long-term Monitoring Program and Experiential Training for Students (LiMPETS). LiMPETS is an organization that conducts citizen science with Bay Area youth such as the CiS interns. We specifically assist in the collection of Pacific Mole Crab population statistics at Ocean Beach during the summer from June through August. The purpose of collecting Pacific Mole Crabs is to monitor Profilicollis spp. (Acanthocephalan parasites) - to which Pacific Mole Crabs serve as intermediate hosts - and to learn more about our environment, as Pacific Mole Crabs are indicator species. During our collections at Ocean Beach we record size, sex, and number of individuals at specific transects. We then take a random sample from the day, return to the lab, and record their sizes, sexes, and Acanthocephalan parasite load. The results of the collection and dissections are then entered into the LiMPETS online database for scientist and researchers to use. Our project will focus on correlations relating to the data collected (Pacific Mole Crab population, parasite load, abiotic and biotic factors, et cetera).

Foodborne protozoan parasites.

PubMed

Dawson, David

2005-08-25

This report addresses Cryptosporidium, Giardia, Cyclospora, and more briefly, Toxoplasma as the main parasitic protozoa of concern to food production worldwide. Other parasitic protozoa may be spread in food or water but are not considered as great a risk to food manufacture. The protozoan parasites Cryptosporidium, Giardia, and Cyclospora have proven potential to cause waterborne and foodborne disease. Toxoplasma gondii has been considered a risk in specific cases, but humans are not its primary host. Cryptosporidium and Giardia are widespread in the environment, particularly the aquatic environment, and major outbreaks of cryptosporidiosis and giardiasis have occurred as a result of contaminated drinking water. Large outbreaks of waterborne cyclosporiasis have not been identified. Cryptosporidium, Giardia, and Cyclospora have potential significance in the preparation and consumption of fresh produce and in catering practice, in which ready-to-eat foods may be served that have not received heat treatment. None of the three organisms Cryptosporidium, Giardia, and Cyclospora has been shown to be a problem for heat processed food or tap water that has undergone appropriate treatment at a water treatment works. All three are sensitive to standard pasteurisation techniques. Although humans are not a primary host for T. gondii, the potential exists for both waterborne and foodborne toxoplasmosis. Parasitic protozoa do not multiply in foods, but they may survive in or on moist foods for months in cool, damp environments. Their ecology makes control of these parasites difficult. For general control of parasitic protozoa in the food chain, the following steps are necessary: - Follow good hygienic practice in food service and catering industries.- Minimise dissemination of cysts and oocysts in the farming environment and via human waste management.- Include these microorganisms in Hazard Analysis Critical Control Point (HACCP) plans of water suppliers, industries or sectors that use fresh produce, and operations in which contaminated process or ingredient water could end up in the product (e.g., where water supplies may become contaminated).

Spot drip application of dimethyl disulfide as a post-plant treatment for the control of plant parasitic nematodes and soilborne pathogens in grape production.

PubMed

Cabrera, J Alfonso; Wang, Dong; Gerik, James S; Gan, Jay

2014-07-01

Plant parasitic nematodes and soilborne pathogens can reduce the overall productivity in grape production. Not all grape growers apply soil fumigants before planting, and there is no single rootstock resistant to all nematode species. The aim of this investigation was to evaluate the effect of dimethyl disulfide (DMDS) applied at 112, 224, 448 and 897 kg ha(-1) as a post-plant treatment against soilborne plant parasitic nematodes and pathogens on the grape yield in established grapevines. In microplot and field trials, post-plant fumigation with DMDS controlled citrus (Tylenchulus semipenetrans), root-knot (Meloidogyne spp.), pin (Paratylenchus spp.) and ring (Mesocriconema xenoplax) nematodes in established Thomson Seedless grapevines. However, DMDS did not control the soilborne pathogens Pythium ultimum and Fusarium oxysporum. No indications of phytotoxicity were detected after post-plant fumigation with DMDS. In the field trial, grape yield was significantly higher with the lowest DMDS rate, but no difference among other rates was observed in comparison with the untreated control. Post-plant fumigation with DMDS controlled plant parasitic nematodes in established grapevines but was less efficacious against soilborne pathogens. Low rates of DMDS were sufficient for nematode control and increased the grape yield, probably without affecting beneficial soil organisms. Further research on evaluating the potential effect of DMDS against beneficial soil organisms is needed. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

An Overview of Trypanosoma brucei Infections: An Intense Host-Parasite Interaction.

PubMed

Ponte-Sucre, Alicia

2016-01-01

Trypanosoma brucei rhodesiense and T. brucei gambiense , the causative agents of Human African Trypanosomiasis, are transmitted by tsetse flies. Within the vector, the parasite undergoes through transformations that prepares it to infect the human host. Sequentially these developmental stages are the replicative procyclic (in which the parasite surface is covered by procyclins) and trypo-epimastigote forms, as well as the non-replicative, infective, metacyclic form that develops in the vector salivary glands. As a pre-adaptation to their life in humans, metacyclic parasites begin to express and be densely covered by the Variant Surface Glycoprotein (VSG). Once the metacyclic form invades the human host the parasite develops into the bloodstream form. Herein the VSG triggers a humoral immune response. To avoid this humoral response, and essential for survival while in the bloodstream, the parasite changes its cover periodically and sheds into the surroundings the expressed VSG, thus evading the consequences of the immune system activation. Additionally, tools comparable to quorum sensing are used by the parasite for the successful parasite transmission from human to insect. On the other hand, the human host promotes clearance of the parasite triggering innate and adaptive immune responses and stimulating cytokine and chemokine secretion. All in all, the host-parasite interaction is extremely active and leads to responses that need multiple control sites to develop appropriately.

Do Native Parasitic Plants Cause More Damage to Exotic Invasive Hosts Than Native Non-Invasive Hosts? An Implication for Biocontrol

PubMed Central

Li, Junmin; Jin, Zexin; Song, Wenjing

2012-01-01

Field studies have shown that native, parasitic plants grow vigorously on invasive plants and can cause more damage to invasive plants than native plants. However, no empirical test has been conducted and the mechanism is still unknown. We conducted a completely randomized greenhouse experiment using 3 congeneric pairs of exotic, invasive and native, non-invasive herbaceous plant species to quantify the damage caused by parasitic plants to hosts and its correlation with the hosts' growth rate and resource use efficiency. The biomass of the parasitic plants on exotic, invasive hosts was significantly higher than on congeneric native, non-invasive hosts. Parasites caused more damage to exotic, invasive hosts than to congeneric, native, non-invasive hosts. The damage caused by parasites to hosts was significantly positively correlated with the biomass of parasitic plants. The damage of parasites to hosts was significantly positively correlated with the relative growth rate and the resource use efficiency of its host plants. It may be the mechanism by which parasitic plants grow more vigorously on invasive hosts and cause more damage to exotic, invasive hosts than to native, non-invasive hosts. These results suggest a potential biological control effect of native, parasitic plants on invasive species by reducing the dominance of invasive species in the invaded community. PMID:22493703

Effects of ethanol extract of Artemisia annua L. against monogenean parasites of Heterobranchus longifilis.

PubMed

Ekanem, Albert P; Brisibe, Ebiamadon Andi

2010-04-01

Ethanol extract of Artemisia annua was effective in the dislodgement and mortality of monogenean parasites of juvenile Heterobranchus longifilis at concentrations ranging from 50 to 200 mg/l. Five hundred 1-week-old juvenile fish were stocked in hapa in earthen pond for 7 days to accumulate parasites. The approximate number of parasites per fish was confirmed by counting the number of parasites attached to body surfaces and the gills with a stereo-microscope before being exposed to the extract under in vivo conditions. The bioactivity of the extract was conducted in plastic Petri dishes with three replications and controls. The results obtained from A. annua extract were matched against those produced by pure artemisinin and artesunate powder, respectively, under similar experimental conditions. There was a faster effect of pure artemisinin crystals on the parasites as compared to A. annua extract and artesunate. Coagulation of parasite cells was observed with artemisinin treatment, whereas parasites were merely dislodged from their attachment organs and killed some hours later in the same concentration of A. annua. There were positive correlations between the number of parasites dislodged/killed and the concentration of A. annua extract, artemisinin, and artesunate powder, respectively, as well as the duration of exposure of affected fish to the substances. This led to the conclusion that A. annua contains substances that are effective against helminthes parasites of H. longifilis.

Parasite control practices and public perception of parasitic diseases: A survey of dog and cat owners.

PubMed

Matos, Mariana; Alho, Ana Margarida; Owen, Sinclair Patrick; Nunes, Telmo; Madeira de Carvalho, Luís

2015-11-01

Drugs used in the control of internal and external parasites in companion animals play a crucial role in Animal and Public Health. To ensure continuing protection, these drugs should be administered regularly and in intervals, as suggested by the manufacturers. To assess parasite control practices and other related factors, including the degree of public awareness on the topic, 312 dog and cat owners were surveyed while attending the Small Animal Hospital, Faculty of Veterinary Medicine, Lisbon University. Results showed that 89.7% of the dogs were currently being treated with endoparasitic drugs. Of these, 74.3% were dewormed every four months or longer and merely 11.8% with the recommended treatment regimen (minimum quarterly). In cats, 63.6% were being treated with endoparasitic drugs and 85.7% of these were irregularly dewormed every four months or longer and merely 5.5% with the recommended treatment regimen (minimum quarterly). Combinations of praziquantel, pyrantel embonate and febantel were the most commonly used drugs in dogs, whereas macrocyclic lactones were more frequently used in cats. Regarding external parasitic control, 92.2% of the dogs were being treated, 50.5% of these at monthly intervals (all-year round or seasonally). The most common ectoparasitic drug formulation used on dogs was the spot-on imidacloprid+permethrin (89%). Only 28.4% of the dogs were uninterruptedly protected throughout the year from the main canine vector borne diseases transmitted by fleas, ticks, sandflies and mosquitoes. Merely 63.6% of the cats were being controlled with ectoparasitic drugs, most at infrequent drug intervals and imidacloprid was the most frequently used drug on cats (44.4%). Additionally, 85% of the respondents had never heard of the word "zoonosis" and 37% of them did not collect their dog's faeces in all public places. Scabies, toxoplasmosis and leishmaniasis were the most frequent parasitic diseases identified by the public in this survey. Although the majority of pet owners give antiparasitic drugs, our results show that most of them do not follow the manufacturers recommendations, deworming at irregular and consequently ineffective intervals. Therefore, it is of utmost importance for the veterinarians to educate pet owners regarding parasite cycles, methods of prevention and transmission mechanisms, as well as to follow the drug recommendations, in order, respectively, to increase their awareness and thereby improve the effectiveness of the available control measures. Copyright © 2015 Elsevier B.V. All rights reserved.

Prevalence of Intestinal Parasites and Associated Factors among Pulmonary Tuberculosis Suspected Patients Attending University of Gondar Hospital, Gondar, Northwest Ethiopia.

PubMed

Tegegne, Yalewayker; Wondmagegn, Tadelo; Worku, Ligabaw; Jejaw Zeleke, Ayalew

2018-01-01

Intestinal parasitic infections are among the major public health problems in developing countries. Hence, it is significant to explore coinfection with intestinal parasites and pulmonary tuberculosis because coinfection increases the complexity of control and prevention of pulmonary tuberculosis and parasitic diseases. To assess the prevalence of intestinal parasites among pulmonary tuberculosis suspected patients. Institutional based cross-sectional study was conducted at University of Gondar Hospital from March to May, 2017. Stool samples were taken from each participant and examined by direct microscopy and concentration technique. Descriptive statistics was performed and chi-square test was used to show the association between variables. P values of <0.05 were considered statistically significant. Intestinal parasites were detected in 50 (19.6%) among a total of 256 pulmonary tuberculosis suspected patients who were included in the study, whereas the prevalence of pulmonary tuberculosis was 16.8% (43/256). Pulmonary tuberculosis and intestinal parasite coinfection was detected in 5 (2.0%) of the participants. The most prevalent intestinal parasites infection in this study was Ascaris lumbricoides, 15 (5.85%), followed by Entamoeba histolytica/dispar, 14 (5.46%), and Hookworm, 13 (5.1%). The prevalence of intestinal parasites and their coinfection rate with pulmonary tuberculosis among pulmonary tuberculosis suspected patients were considerable.

Longitudinal study of parasite-induced mortality of a long-lived host: the importance of exposure to non-parasitic stressors.

PubMed

Chin, Hilary M-H; Luong, Lien T; Shostak, Allen W

2017-12-01

Hosts face mortality from parasitic and environmental stressors, but interactions of parasitism with other stressors are not well understood, particularly for long-lived hosts. We monitored survival of flour beetles (Tribolium confusum) in a longitudinal design incorporating cestode (Hymenolepis diminuta) infection, starvation and exposure to the pesticide diatomaceous earth (DE). We found that cestode cysticercoids exhibit increasing morphological damage and decreasing ability to excyst over time, but were never eliminated from the host. In the presence of even mild environmental stressors, host lifespan was reduced sufficiently that extensive degradation of cysticercoids was never realized. Median host lifespan was 200 days in the absence of stressors, and 3-197 days with parasitism, starvation and/or DE. Early survival of parasitized hosts was higher relative to controls in the presence of intermediate concentrations of DE, but reduced under all other conditions tested. Parasitism increased host mortality in the presence of other stressors at times when parasitism alone did not cause mortality, consistent with an interpretation of synergy. Environmental stressors modified the parasite numbers needed to reveal intensity-dependent host mortality, but only rarely masked intensity dependence. The longitudinal approach produced observations that would have been overlooked or misinterpreted if survival had only been monitored at a single time point.

Parasitism as the main factor shaping peptide vocabularies in current organisms.

PubMed

Zemková, Michaela; Zahradník, Daniel; Mokrejš, Martin; Flegr, Jaroslav

2017-06-01

Self/non-self-discrimination by vertebrate immune systems is based on the recognition of the presence of peptides in proteins of a parasite that are not contained in the proteins of a host. Therefore, a reduction of the number of 'words' in its own peptide vocabulary could be an efficient evolutionary strategy of parasites for escaping recognition. Here, we compared peptide vocabularies of 30 endoparasitic and 17 free-living unicellular organisms and also eight multicellular parasitic and 16 multicellular free-living organisms. We found that both unicellular and multicellular parasites used a significantly lower number of different pentapeptides than free-living controls. Impoverished pentapeptide vocabularies in parasites were observed across all five clades that contain both the parasitic and free-living species. The effect of parasitism on a number of peptides used in an organism's proteins is larger than effects of all other studied factors, including the size of a proteome, the number of encoded proteins, etc. This decrease of pentapeptide diversity was partly compensated for by an increased number of hexapeptides. Our results support the hypothesis of parasitism-associated reduction of peptide vocabulary and suggest that T-cell receptors mostly recognize the five amino acids-long part of peptides that are presented in the groove of major histocompatibility complex molecules.

Expression of parasite genetic variation changes over the course of infection: implications of within-host dynamics for the evolution of virulence

PubMed Central

Clerc, Melanie; Ebert, Dieter; Hall, Matthew D.

2015-01-01

How infectious disease agents interact with their host changes during the course of infection and can alter the expression of disease-related traits. Yet by measuring parasite life-history traits at one or few moments during infection, studies have overlooked the impact of variable parasite growth trajectories on disease evolution. Here we show that infection-age-specific estimates of host and parasite fitness components can reveal new insight into the evolution of parasites. We do so by characterizing the within-host dynamics over an entire infection period for five genotypes of the castrating bacterial parasite Pasteuria ramosa infecting the crustacean Daphnia magna. Our results reveal that genetic variation for parasite-induced gigantism, host castration and parasite spore loads increases with the age of infection. Driving these patterns appears to be variation in how well the parasite maintains control of host reproduction late in the infection process. We discuss the evolutionary consequences of this finding with regard to natural selection acting on different ages of infection and the mechanism underlying the maintenance of castration efficiency. Our results highlight how elucidating within-host dynamics can shed light on the selective forces that shape infection strategies and the evolution of virulence. PMID:25761710

Prevalence of Intestinal Parasitic Infection among Food Handlers in Northwest Iran

PubMed Central

Balarak, Davoud; Modrek, Mohammad Jafari; Bazrafshan, Edris; Ansari, Hossein; Kord Mostafapour, Ferdos

2016-01-01

Parasitic diseases are among the most important infectious diseases and pose health problems in many countries, most especially in developing countries. Workers at food centers could transmit parasitic infections in the absence of sanitation. This is a descriptive study conducted to determine the prevalence of intestinal parasitic infections in food clerks in the city of Tabriz in 2014. Data was recorded in the offices of the health center for all food handlers who were referred to the laboratory for demographic and stool tests to receive the health card. Parasitic infection was observed in 172 cases (3.73%) of 4612 samples. A total of 156 positive samples (90.69%) were related to protozoa and 16 (9.3%) were related to helminthes. Most of the parasitic infections were related to Giardia and Entamoeba coli and the lowest infection was related to H. nana. Also, there was a significant relationship between level of education and parasitic infection rate (P = 0.0044). But there was no significant difference between the type of infection and amount of intestinal parasites. The results show that the prevalence of intestinal parasites, especially pathogenic protozoa, is common in some food handlers. Therefore, more sanitary controls are required and increasing of education will play a crucial role in improving the health of these people. PMID:27127643

Endohelminths in Bird Hosts from Northern California and an Analysis of the Role of Life History Traits on Parasite Richness.

PubMed

Hannon, Emily R; Kinsella, John M; Calhoun, Dana M; Joseph, Maxwell B; Johnson, Pieter T J

2016-04-01

The life history characteristics of hosts often influence patterns of parasite infection either by affecting the likelihood of parasite exposure or the probability of infection after exposure. In birds, migratory behavior has been suggested to affect both the composition and abundance of parasites within a host, although whether migratory birds have more or fewer parasites is unclear. To help address these knowledge gaps, we collaborated with airports, animal rescue/rehabilitation centers, and hunter check stations in the San Francisco Bay Area of California to collect 57 raptors, egrets, herons, ducks, and other waterfowl for parasitological analysis. After dissections of the gastrointestinal tract of each host, we identified 64 taxa of parasites: 5 acanthocephalans, 24 nematodes, 8 cestodes, and 27 trematodes. We then used a generalized linear mixed model to determine how life history traits influenced parasite richness among bird hosts, while controlling for host phylogeny. Parasite richness was greater in birds that were migratory with larger clutch sizes and lower in birds that were herbivorous. The effects of clutch size and diet are consistent with previous studies and have been linked to immune function and parasite exposure, respectively, whereas the effect of migration supports the hypothesis of "migratory exposure" rather than that of "migratory escape."

Potential interactions between metazoan parasites of the Mayan catfish Ariopsis assimilis and chemical pollution in Chetumal Bay, Mexico.

PubMed

Vidal-Martínez, V M; Aguirre-Macedo, M L; Noreña-Barroso, E; Gold-Bouchot, G; Caballero-Pinzón, P I

2003-06-01

The effect of pollutants on the intensity of infection of metazoan parasites in the Mayan catfish, Ariopsis assimilis was investigated. Data were collected on pollutants and metazoan parasites from 76 catfish from five localities in Chetumal Bay in October, 1996. Nineteen pollutants (pesticides, polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs)) were found in the catfish livers. Heavy metal content was not determined. Nineteen metazoan parasite species were recovered. After controlling for fish length and sampling station, there was a significant negative linear relationship between the intensity of the larval digenean Mesostephanus appendiculatoides and 1,1,1,-trichloro-2,2-bis (4-chlorophenyl) ethane (DDT) concentrations. This negative relationship may be explained either by the effect of the pesticide on the mortality of (i) free-living larval forms, (ii) metacercariae in the fish, (iii) infected fish or (iv) intermediate host snails. There were significant differences between fish parasitized and not parasitized with M. appendiculatoides with respect to their DDT concentrations. There were also significant differences between the variances of the mean Clark's coefficient of condition values between catfish parasitized and not parasitized by M. appendiculatoides, with the variance of non-parasitized catfish being significantly larger. The results provided statistical evidence that DDT has a detrimental effect on M. appendiculatoides infection intensity. Furthermore, the significantly larger variance value of Clark's coefficient for non-parasitized fish suggested that DDT affects both the parasite and general host condition.