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Sample records for parasite setaria cervi

  1. Effect of ferulic acid from Hibiscus mutabilis on filarial parasite Setaria cervi: molecular and biochemical approaches.

    PubMed

    Saini, Prasanta; Gayen, Prajna; Nayak, Ananya; Kumar, Deepak; Mukherjee, Niladri; Pal, Bikas C; Sinha Babu, Santi P

    2012-12-01

    In the reported work the in vitro activity of a methanolic extract of leaves of Hibiscus mutabilis (Malvaceae) against bovine Setaria cervi worms has been investigated. Bioassay-guided fractionation led to isolation of ferulic acid from ethyl acetate fraction. The crude extract and ferulic acid, the active molecule, showed significant microfilaricidal as well as macrofilaricidal activities against the microfilaria (L(1)) and adult of S. cervi by both a worm motility and MTT reduction assay. The findings thus provide a new lead for development of a filaricidal drug from natural products. To examine the possible mechanism of action of ferulic acid, the involvement of apoptosis in adult worms of S. cervi was investigated. We found extreme cellular disturbances in ferulic acid-treated adult worms characterized by chromatin condensation, in situ DNA fragmentation and nucleosomal DNA laddering. In this work we are reporting for the first time that ferulic acid exerts its antifilarial effect through induction of apoptosis and by downregulating and altering the level of some key antioxidants (GSH, GST and SOD) of the filarial nematode S. cervi. Our results have provided experimental evidence supporting that ferulic acid causes an increased proapoptotic gene expression and decreased expression of anti-apoptotic genes simultaneously with an elevated level of ROS and gradual dose dependent decline of parasitic GSH level. We also observed a gradual dose dependent elevation of GST and SOD activity in the ferulic acid treated worms.

  2. Identification and characterization of novel membrane-bound PRL protein tyrosine phosphatases from Setaria cervi, a bovine filarial parasite.

    PubMed

    Singh, Neetu; Yadav, Smita; Rathaur, Sushma

    2015-11-01

    A significant amount of protein tyrosine phosphatase (PTP) activity was detected in the detergent-soluble membrane-bound fraction of Setaria cervi, a bovine filarial parasite. The membrane-bound PTP activity was significantly inhibited when the adult parasites were exposed to compounds having antifilarial activity like aspirin and SK7 as well as phenylarsine oxide, a specific PTP inhibitor suggesting that this activity is stress regulated. Further, this enzyme was purified as a single protein of apparently 21 kDa using two different chromatographic techniques. The MALDI-MS/MS analysis of its peptides showed closest match with protein tyrosine phosphatase PRL (Aedes aegypti). This purified enzyme (named as PRL) showed maximum activity at pH 5.5/37 °C and hydrolysed para nitro phenyl phosphate (pNPP) at the highest rate followed by O-P-L-tyrosine and O-P-L-threonine. It showed significant inhibition by specific inhibitors of PTP such as sodium orthovanadate, phenylarsine oxide and ammonium molybdate and was activated by dithiothreitol (DTT). The active site modification studies suggested involvement of cysteine, arginine, histidine and aspartic acid in the catalytic activity of PRL. The activity of S. cervi PRL was also found to be resistant towards the external oxidative stress. Thus, S. cervi PRL could be taken as a potential target for the management of human lymphatic filariasis.

  3. Effect of diethylcarbamazine, butylated hydroxy anisole and methyl substituted chalcone on filarial parasite Setaria cervi: proteomic and biochemical approaches.

    PubMed

    Rathaur, Sushma; Yadav, Marshleen; Singh, Neetu; Singh, Alka

    2011-08-24

    For survival, parasite exerts several lines of defense of which drug neutralization is one of the major phenomena. Lack of phase I cytochrome P450 in some of the nematode render them depend on the phase II detoxification system involving GST as a major detoxifying enzymes. In present study, the antifilarial DEC, phenolic compound BHA and methyl chalcone have been evaluated for proteomic and biochemical studies in Setaria cervi. BHA and methyl chalcone showed cytotoxic effect leading to irreversible inhibition in motility and viability of parasites. These drugs showed marked alteration in proteomic profile of S. cervi at 100 μM concentration with 10.82, 8.52 and 6.75% downregulated (<0.5) and 7.64, 31.78 and 24.32% upregulated (>1.5) in DEC, BHA and methyl chalcone treatment respectively. Significant depletion in GSH level with increase in NO production was observed. Amongst these compounds, methyl chalcone demonstrated significant inhibitory effect (p<0.05) on GST, PGHS and PTP activity leading to loss of metabolic homeostasis and parasite death. The cytotoxic response and altered expression profile of major enzymes under drug exposure suggested the oxidative stress induced apoptosis as a major cause of parasite killing which was further supported by DNA fragmentation in BHA and methyl chalcone.

  4. Setaria cervi dual specific phosphatase: characterization and its effect on eosinophil degranulation.

    PubMed

    Rathaur, S; Rai, R; Srikanth, E; Srivastava, S

    2009-07-01

    Setaria cervi, a bovine filarial parasite contains significant acid phosphatase (AcP) activity in its various life stages. Two forms of AcP were separated from somatic extract of adult female parasite using cation exchange, gel filtration and concavalin affinity chromatography. One form having a molecular mass of 79 kDa was characterized as dual specific protein tyrosine phosphatase (ScDSP) based on substrate specificity and inhibition studies. With various substrates tested, it showed significant activity in the order of phospho-L-tyrosine>pNPP>ADP>phospho-L-serine. Inhibition by orthovanadate, fluoride, molybdate, and zinc ions further confirms protein tyrosine phosphatase nature of the enzyme. Km and Vmax determined with various substrates were found to be 16.66 mM, 25.0 microM/ml/min with pNPP; 20.0 mM, 40.0 microM/ml/min with phospho-L-tyrosine and 27.0 mM, 25.0 microM/ml/min with phospho-L-serine. KI with pNPP and sodium orthovanadate (IC50 33.0 microM) was calculated to be 50.0 mM. Inhibition with pHMB, silver nitrate, DEPC and EDAC suggested the presence of cysteine, histidine and carboxylate residues at its active site. Cross-reactivity with W. bancrofti-infected sera was demonstrated by Western blotting. ScDSP showed elevated levels of IgE in chronic filarial sera using ELISA. Under in vitro conditions, ScDSP resulted in increased effector function of human eosinophils when stimulated by IgG, which showed a further decrease with increasing enzyme concentration. Results presented here suggest that S. cervi DSP should be further studied to determine its role in pathogenesis and the persistence of filarial parasite.

  5. Identification and characterization of a selenium-dependent glutathione peroxidase in Setaria cervi

    SciTech Connect

    Singh, Anchal; Rathaur, Sushma . E-mail: sushmarathaur@yahoo.com

    2005-06-17

    Setaria cervi a bovine filarial parasite secretes selenium glutathione peroxidase during in vitro cultivation. A significant amount of enzyme activity was detected in the somatic extract of different developmental stages of the parasite. Among different stages, microfilariae showed a higher level of selenium glutathione peroxidase activity followed by males then females. However, when the activity was compared in excretory secretory products of these stages males showed higher activity than microfilariae and female worms. The enzyme was purified from female somatic extract using a combination of glutathione agarose and gel filtration chromatography, which migrated as a single band of molecular mass {approx}20 kDa. Selenium content of purified enzyme was estimated by atomic absorption spectroscopy and found to be 3.5 ng selenium/{mu}g of protein. Further, inhibition of enzyme activity by potassium cyanide suggested the presence of selenium at the active site of enzyme. This is the first report of identification of selenium glutathione peroxidase from any filarial parasite.

  6. Molecular evidence of curcumin-induced apoptosis in the filarial worm Setaria cervi.

    PubMed

    Nayak, Ananya; Gayen, Prajna; Saini, Prasanta; Mukherjee, Niladri; Babu, Santi P Sinha

    2012-09-01

    Curcumin (diferuloyl methane) is a major curcuminoid from Curcuma longa that exhibits various pharmacological effects and has shown multiple beneficial activities. Our understanding of its anticarcinogenic and other activities occurring through curcumin-induced apoptosis in several cancer cells has greatly expanded in recent years. Lymphatic filariasis is a worldwide health problem causing global disability in humans and is caused by filarial nematodes. Development of efficient strategies to promote programmed cell death in filarial worms remains a key challenge for anti-filarial drug developing research and a crucial unmet medical need. In this study, we have taken molecular and biochemical approaches toward understanding the molecular basis for curcumin-mediated anti-filarial activity in the filarial nematode Setaria cervi. Results of MTT assay showed that curcumin causes a significant reduction in viability of Mf and adults and thus acts as a potent macro- and micro-filaricidal agent. Hoechst staining, TUNEL staining, showed several apoptotic nuclei in different parts of curcumin-treated adults. At 25 μM concentration it showed chromosomal DNA fragmentation in adult worms. Our results indicate that curcumin decreases protein and mRNA expression levels of anti-apoptotic gene ced-9 and enhances both the levels of pro-apoptotic genes ced-3 and ced-4 in a dose-dependent manner. All these observations ascertained the apoptogenicity of curcumin at a minimum concentration of 50 μM in this filarial worm. Furthermore, we showed that curcumin causes depletion of parasitic glutathione level, enhances the activities of glutathione S-transferase and superoxide dismutase and stimulates rapid generation of reactive oxygen species (ROS). Here, we present molecular evidence on curcumin-induced apoptosis in the filarial nematode S. cervi with probable involvement of ROS in a caspase-dependent manner.

  7. Surface proteins of Setaria cervi induce inflammation in macrophage through Toll-like receptor 4 (TLR4)-mediated signalling pathway.

    PubMed

    Mukherjee, Su; Mukherjee, Sa; Bhattacharya, S; Sinha Babu, S P

    2017-01-01

    Lymphatic filariasis is a vectorborne parasitic disease that results in morbidities, disabilities and socio-economic loss each year globally. Inflammatory consequences associated with any form of filariasis have drawn special attention. However, the molecular insight behind the inflammation of host macrophage (MФ) is considered as one of the shaded areas in filarial research. Herein, major emphasis was given to study the signalling pathway of MФ inflammation induced by surface proteins (SPs) of filarial parasite through in vitro and in vivo approaches. Twenty-four hours of in vitro stimulation of Raw MФs with endotoxin-free SPs of Setaria cervi resulted in the secretion of pro-inflammatory cytokines (TNF-α and IL-1β) that revealed induction of inflammation, which was found to be elicited from classical NF-кB activation. Moreover, this NF-кB activation was found to be signalled from TLR4 and mediated by the downstream signalling intermediates, viz. MyD88, pTAK1 and NEMO. In vivo studies in adult Wistar rats, experimentally injected with SPs, clearly supported the outcomes of in vitro experiments by showing higher degree of inflammation rather classical activation of the peritoneal MФs. Therefore, SPs from S. cervi cuticle could be responsible for the induction of pro-inflammatory response in MФ, which appears to be propagated through TLR4-NF-кB route.

  8. Antifilarial activity of Mallotus philippensis Lam. on Setaria cervie (Nematoda: Filarioidea) in vitro.

    PubMed

    Singh, R; Singhal, K C; Khan, N U

    1997-10-01

    The effect of aqueous and alcoholic extracts of the leaves of Mallotus philippensis (Lam.) Muell. Arg. was studied on the spontaneous movements of the whole worm and nerve-muscle (n.m.) preparation of Setaria cervi and on the survival of microfilariae in vitro. Both the extracts caused inhibition of spontaneous motility of whole worm and the n.m. preparation of S. Cervi characterized by initial stimulation followed by depression in amplitude. The tone and rate of contractions remained visibly unaffected. Aqueous extract at higher concentration showed immediate reduction in tone. The concentration required to inhibit the movements of n.m. preparation was 1/5th for aqueous and 1/11th for alcoholic extract compared to that for the whole worm, suggesting a cuticular permeability barrier. The stimulatory response of acetylcholine was blocked by aqueous extract on whole worm movements. On the microfilariae the LC50 and LC90 were 18 and 20 ng/ml for aqueous and 12 and 15 ng/ml for alcoholic extracts respectively.

  9. Evidence for the presence of prostaglandin H synthase like enzyme in female Setaria cervi and its inhibition by diethylcarbamazine.

    PubMed

    Rathaur, Sushma; Singh, Alka; Yadav, Marshleen; Rai, Reeta

    2009-07-01

    Experimental evidence has shown that Setaria cervi a bovine filarial parasite contains significant amount of prostaglandin H synthase like activity in the somatic extract of its different life stages. A protein with characteristics of prostaglandin H synthase was purified to homogeneity from female somatic extract using a combination of affinity and gel filtration chromatography. Molecular weight of purified enzyme was 70kDa as determined by SDS-PAGE. Purified enzyme showed high activity with arachidonic acid and TMPD substrates suggests the presence of both cyclooxygenase and peroxidase activity in enzyme. Fluorescence spectroscopy and hemin-associated peroxidase activity confirmed presence of heme in purified enzyme. The K(m) and V(max) values using arachidonic acid were determined to be 79+/-1.5microM and 0.165+/-0.2U/ml, respectively. Further, indomethacin and aspirin, specific inhibitors for PGHS, significantly inhibited the enzyme activity. Diethylcarbamazine, an antifilarial drug inhibited the microfilarial PGHS like activity as well as their motility. Here we are reporting for the first time PGHS like activity in filarial parasite and its inhibition with DEC which provide that this enzyme could be used as a drug target.

  10. Evidence of reactive oxygen species (ROS) mediated apoptosis in Setaria cervi induced by green silver nanoparticles from Acacia auriculiformis at a very low dose.

    PubMed

    Saini, Prasanta; Saha, Swadhin Kr; Roy, Priya; Chowdhury, Pranesh; Sinha Babu, Santi P

    2016-01-01

    Green synthesis of silver nanomaterial plays a pivotal role in the growing field of nanotechnology. Development of anti-parasitic drugs from plant metabolites has been in regular practice from the ancient period but most of them were discarded due to their inefficiency to control diseases effectively. At present, nanoparticles are used for developing anti-parasitic therapy for their unique properties such as smallest in size, bio-ability, bio-compatibility and penetration capacity into a cell. The present study aims at synthesis of silver nanoparticles (AgNPs) by using funicles extract of Acacia auriculiformis and tests its efficacy as antifilarial. Experimental evidence show that AgNPs are effective at a very low concentration compared to crude plant extracts. Synthesis of these nanoparticles is a single-step, biogenic, cost effective and eco-friendly process. Synthesized nanoparticles were characterized by UV-Vis spectroscopy, TEM, SAED, FTIR, EDX, FESEM and Z-potential. The antifilarial efficacy of AgNPs was tested against different life cycle stages of bovine filarial parasite Setaria cervi by morphological study, motility assessment and viability assay. These nanoparticles are found to have antifilarial activity with LC50 of 5.61 μg/mL and LC90 of 15.54 μg/mL against microfilaria of S. cervi. The microscopic findings and the detailed molecular studies confirmed that green synthesized AgNPs were effective enough to induce apoptosis through up regulation of ROS (reactive oxygen species).

  11. Antifilarial effects of polyphenol rich ethanolic extract from the leaves of Azadirachta indica through molecular and biochemical approaches describing reactive oxygen species (ROS) mediated apoptosis of Setaria cervi.

    PubMed

    Mukherjee, Niladri; Mukherjee, Suprabhat; Saini, Prasanta; Roy, Priya; Sinha Babu, Santi P

    2014-01-01

    Lymphatic filariasis, a global cause of morbidity needs much more attention in developing potent therapeutics that can be effective against both microfilariae (mf) and adults. Efficient botanicals that can induce apoptosis of filarial parasites possibly can provide a direction towards developing new class of antifilarials. In this work we have evaluated the antifilarial efficacy of an optimized polyphenol rich ethanolic extract of Azadirachta indica leaves (EEA). A. indica A. Juss has been widely used in the traditional Indian medicinal system 'Ayurveda' for the treatment of a variety of ailments. A thorough investigation towards biochemical and molecular mechanisms describing ROS mediated apoptosis in Setaria cervi was performed. Motility reduction, MTT reduction assay and dye exclusion test have confirmed the micro- and macrofilaricidal potential of EEA. Alterations were visible in mf and trichrome stained section of EEA-treated adult worms. We have found cellular disturbances in EEA-treated parasites characterized by chromatin condensation, in situ DNA fragmentation and nucleosomal DNA laddering. Depletion in worm GSH level and elevation in parasite GST, SOD, catalase, GPx and superoxide anion indicated the generation of ROS. Our results provided experimental evidence supporting that EEA causes a decreased expression of anti-apoptotic genes and increased pro-apoptotic gene expression at the level of both transcription and translation. Here we are reporting for the first time that antifilarial activity of EEA is mediated by ROS up regulation and apoptosis.

  12. Parasitism of the deer ked, Lipoptena cervi, on the moose, Alces alces, in eastern Finland.

    PubMed

    Paakkonen, T; Mustonen, A-M; Roininen, H; Niemelä, P; Ruusila, V; Nieminen, P

    2010-12-01

    The deer ked, Lipoptena cervi L. (Diptera: Hippoboscidae), is an ectoparasitic fly that spread to Finland in the early 1960s from the southeast across the Soviet border. It is currently a common parasite of the moose, Alces alces (Artiodactyla: Cervidae), in the southern part of the country and its area of distribution is gradually spreading to Finnish Lapland, where it will come into contact with another potential cervid host, the semi-domesticated reindeer, Rangifer tarandus tarandus. The aim of this study was to determine the intensity of deer ked parasitism on the moose in eastern Finland. Whole skins of 23 moose were examined for the presence of deer keds, which were extracted and their total numbers estimated. The intensity of deer ked parasitism was correlated to the age, sex, skin area and anatomical region of the host. Bulls had the highest total number of keds (10616 ± 1375) and the highest deer ked density (35.7 ± 4.4 keds/dm(2) of skin). Cows had a higher total number of keds than calves (3549 ± 587 vs. 1730 ± 191), but ked densities on cows and calves were roughly equal (11.8 ± 1.7 vs. 9.4 ± 1.1 keds/dm(2) of skin). The density of keds was highest on the anterior back, followed by the posterior back, front limbs, abdomen, head and hind limbs. The sex ratio of deer keds was close to equal (male : female, 1.0 : 1.1). After they had consumed blood, male keds were heavier than females. As the total numbers and densities of deer keds were higher than reported previously on moose or for any other louse fly species, the effects of parasitism on the health of the host species should be determined.

  13. Oxidative activities in mitochondria-like particles from Setaria digitata, a filarial parasite.

    PubMed Central

    Raj, R K; Puranam, R S; Kurup, C K; Ramasarma, T

    1988-01-01

    The oxidative metabolic potential of Setaria digitata, a filarial parasite found in the intraperitoneal cavity of cattle, was investigated. These worms showed active wriggling movements which were not affected by respiratory poisons such as cyanide, rotenone and malonate. They also possessed cyanide-insensitive and glucose-independent oxygen consumption pathways. By differential centrifugation of sucrose homogenates, a fraction containing mitochondria-like particles was obtained in which the activity of the marker enzyme, succinate dehydrogenase, was recovered. This fraction catalysed succinate- and NADH-dependent reduction of both cytochrome c and dyes. Oxygen uptake found with succinate, NADH and ascorbate as substrates was not sensitive to cyanide. Cytochromes could not be detected in either this fraction or homogenates of the worms. H2O2 generation with a number of substrates and lipid peroxidation by measuring malondialdehyde formed as well as by accompanying oxygen uptake were demonstrated in the mitochondria-like particles. A lipid quinone, possibly with a short side chain and related to ubiquinone, was detected in the worms. The results suggested the existence of two cyanide-insensitive oxygen-consuming reactions in Setaria: one respiratory substrate-independent lipid peroxidation, and a second substrate-dependent reaction that requires an auto-oxidizable quinone but not a cytochrome system. PMID:3223930

  14. Oxidative activities in mitochondria-like particles from Setaria digitata, a filarial parasite.

    PubMed

    Raj, R K; Puranam, R S; Kurup, C K; Ramasarma, T

    1988-12-01

    The oxidative metabolic potential of Setaria digitata, a filarial parasite found in the intraperitoneal cavity of cattle, was investigated. These worms showed active wriggling movements which were not affected by respiratory poisons such as cyanide, rotenone and malonate. They also possessed cyanide-insensitive and glucose-independent oxygen consumption pathways. By differential centrifugation of sucrose homogenates, a fraction containing mitochondria-like particles was obtained in which the activity of the marker enzyme, succinate dehydrogenase, was recovered. This fraction catalysed succinate- and NADH-dependent reduction of both cytochrome c and dyes. Oxygen uptake found with succinate, NADH and ascorbate as substrates was not sensitive to cyanide. Cytochromes could not be detected in either this fraction or homogenates of the worms. H2O2 generation with a number of substrates and lipid peroxidation by measuring malondialdehyde formed as well as by accompanying oxygen uptake were demonstrated in the mitochondria-like particles. A lipid quinone, possibly with a short side chain and related to ubiquinone, was detected in the worms. The results suggested the existence of two cyanide-insensitive oxygen-consuming reactions in Setaria: one respiratory substrate-independent lipid peroxidation, and a second substrate-dependent reaction that requires an auto-oxidizable quinone but not a cytochrome system.

  15. Absence of Wolbachia endobacteria in Sri Lankan isolates of the nematode parasite of animals Setaria digitata.

    PubMed

    Voronin, Denis; Abeykoon, A M L L; Gunawardene, Y I Silva; Dassanayake, Ranil S

    2015-01-30

    Setaria digitata is an animal filarial parasite with natural hosts of cattle and buffaloes that causes mild disease conditions. Infection of non-permissive hosts such as goats, sheep and horses, by this nematode can cause cerebrospinal nematodiasis that leads to lumbar paralysis and the eventual death of the animals and inflicts considerable economic losses on livestock farmers. Wolbachia are obligate mutualistic endosymbionts for some filarial nematodes and are currently being targeted for the control of diseases caused by these parasites. However, little is known about the occurrence of this endosymbiont in the Setariidae family. In this work, worms collected from infected cattle in Sri Lanka were morphologically identified as S. digitata and tested for the presence of Wolbachia by PCR screening using the WSP- and Wolbachia-specific 16S rRNA and multilocus sequence typing primers that were designed to amplify the gatB, coxA, hcpA, ftsZ and fbpA sequences of Wolbachia. The presence of endobacteria in S. digitata was also examined by whole-mount immunofluorescence staining of the parasites and transmission electron microscopic studies. These analyses did not produce evidence of presence of Wolbachia or any other endosymbiotic bacteria in S. digitata, whereas such evidence was found in Brugia malayi, which was used as a positive control in this study.

  16. In silico characterization of a RNA binding protein of cattle filarial parasite Setaria digitata

    PubMed Central

    Nagaratnam, Nirupa; Karunanayake, Eric Hamilton; Tennekoon, Kamani Hemamala; Samarakoon, Sameera Ranganath; Mayan, Karthika

    2014-01-01

    Human lymphatic filariasis (HLF) is a neglected tropical disease which threatens nearly 1.4 billion people in 73 countries worldwide. Wuchereria bancrofti is the major causative agent of HLF and it closely resembles cattle filarial parasite Setaria digitata. Due to difficulties in procuring W. bancrofti parasite material, S. digitata cDNA library has been constructed to identify novel drug targets against HLF and many of the cDNA sequences are yet to be assigned structure and function. In this study, a 549 bp long cDNA (sdrbp) has been sequenced and characterized in silico. The shortest ORF of 249 bp from the isolated cDNA encodes a polypeptide of 82 amino acids and shows an amino acid identity of 54% with the RRM domain of human cleavage stimulation factor-64 kDa subunit (CstF-64). Structure of the protein (sdRBP) obtained by homology modelling using RRM of CstF-64 as template adopts classical RRM topology (β1α1β2β3α2β4). sdRBP model built was validated by superimposition tools and Ramachandran plot analysis. CstF-64 plays an important role in pre-mRNA polyadenylation by interacting with specific GU-rich downstream sequence element. Molecular docking studies of sdRBP with different RNA molecules revealed that sdRBP has greater binding affinity to GU-rich RNA and comparable results were obtained upon similar docking of RRM of CstF-64 with the same RNA molecules. Therefore, sdRBP is likely to perform homologous function in S. digitata. This study brings new dimensions to the functional analysis of RNA binding proteins of S. digitata and their evaluation as new drug targets against HLF. PMID:25258487

  17. In silico characterization of a RNA binding protein of cattle filarial parasite Setaria digitata.

    PubMed

    Nagaratnam, Nirupa; Karunanayake, Eric Hamilton; Tennekoon, Kamani Hemamala; Samarakoon, Sameera Ranganath; Mayan, Karthika

    2014-01-01

    Human lymphatic filariasis (HLF) is a neglected tropical disease which threatens nearly 1.4 billion people in 73 countries worldwide. Wuchereria bancrofti is the major causative agent of HLF and it closely resembles cattle filarial parasite Setaria digitata. Due to difficulties in procuring W. bancrofti parasite material, S. digitata cDNA library has been constructed to identify novel drug targets against HLF and many of the cDNA sequences are yet to be assigned structure and function. In this study, a 549 bp long cDNA (sdrbp) has been sequenced and characterized in silico. The shortest ORF of 249 bp from the isolated cDNA encodes a polypeptide of 82 amino acids and shows an amino acid identity of 54% with the RRM domain of human cleavage stimulation factor-64 kDa subunit (CstF-64). Structure of the protein (sdRBP) obtained by homology modelling using RRM of CstF-64 as template adopts classical RRM topology (β1α1β2β3α2β4). sdRBP model built was validated by superimposition tools and Ramachandran plot analysis. CstF-64 plays an important role in pre-mRNA polyadenylation by interacting with specific GU-rich downstream sequence element. Molecular docking studies of sdRBP with different RNA molecules revealed that sdRBP has greater binding affinity to GU-rich RNA and comparable results were obtained upon similar docking of RRM of CstF-64 with the same RNA molecules. Therefore, sdRBP is likely to perform homologous function in S. digitata. This study brings new dimensions to the functional analysis of RNA binding proteins of S. digitata and their evaluation as new drug targets against HLF.

  18. Oxidative stress plays major role in mediating apoptosis in filarial nematode Setaria cervi in the presence of trans-stilbene derivatives.

    PubMed

    Mukherjee, Niladri; Parida, Pravat Kumar; Santra, Abhishek; Ghosh, Tamashree; Dutta, Ananya; Jana, Kuladip; Misra, Anup Kumar; Sinha Babu, Santi P

    2016-04-01

    Lymphatic filariasis, affecting around 120 million people in 80 countries worldwide, is an extremely painful disease and caused permanent and long term disability. Owing to its alarming prevalence there is immediate need for development of new therapeutics. A series of trans-stilbene derivatives were synthesized using aqueous reaction condition showing potential as antifilarial agents demonstrated in vitro. MTT reduction assay and dye exclusion test were performed to evaluate the micro and macrofilaricidal potential of these compounds. Amid 20 trans-stilbene derivatives together with Resveratrol (RSV), a multifunctional natural product was screened; nine compounds (28, 29, 33, 35, 36, 38, 39, 41 and 42) have showed promising micro and macrofilaricidal activities and four of them (28, 39, 41 and 42) showed better effectiveness than RSV. In the treated parasites apoptosis was established by DNA laddering, in situ DNA fragmentation and FACS analysis. The generation of ROS in the treated parasites was indicated by the depletion in the level of GSH, GR and GST activity and elevation of SOD, catalase, GPx activity and superoxide anion and H2O2 level. Along with the ROS generation and oxidative stress, the decreased expression of anti-apoptotic ced-9 gene and increased expression of nematode specific pro-apoptotic genes, egl-1, ced-4 and ced-3 at the level of transcription and translation level; the up-regulation of caspase-3 activity and involvement of caspase-8,9,3, cytochrome-c and PARP were also observed and which denotes the probable existence of both extrinsic and intrinsic pathways apoptosis in parasitic nematodes. This observation is reported first time and thus it confirmed the mode of action and effectiveness of the compounds. Further, the comparative bioavailability-pharmacokinetics studies showed that compound 28 possesses comparable properties with Ivermectin. This study will certainly intensify our understanding of the pharmacological importance of trans

  19. Setaria viridis.

    PubMed

    Van Eck, Joyce; Swartwood, Kerry

    2015-01-01

    Interest in plant model systems for genetic, biological, and functional genomics studies stems from advantages they provide in terms of fast generation time, small stature, and simple growth requirements. A model species would be especially advantageous for the studies of C4 photosynthetic grasses, which currently present practical challenges. These include long seed-to-seed generation times, and because of their large size at maturity they require large growing areas. One potential model of interest for C4 photosynthetic grasses is Setaria viridis. It has all the desirable aforementioned attributes for a model; however, for it to be adopted as a model for functional genomics studies, gene transfer methodology is also needed. In this chapter, we describe methods for Agrobacterium tumefaciens-mediated transformation of seed-derived callus. Vectors used for gene constructs contained the hygromycin phosphotransferase gene as a selectable marker. The transition of transgenic lines to soil was straightforward; plants started to flower in 1-3 weeks, with seeds ready to harvest approximately 5 weeks later.

  20. The parasitic fauna of the European bison (Bison bonasus) (Linnaeus, 1758) and their impact on the conservation. Part 1. The summarising list of parasites noted.

    PubMed

    Karbowiak, Grzegorz; Demiaszkiewicz, Aleksander W; Pyziel, Anna M; Wita, Irena; Moskwa, Bożena; Werszko, Joanna; Bień, Justyna; Goździk, Katarzyna; Lachowicz, Jacek; Cabaj, Władysław

    2014-09-01

    During the current century, 88 species of parasites have been recorded in Bison bonasus. These are 22 species of protozoa (Trypanosoma wrublewskii, T. theileri, Giardia sp., Sarcocystis cruzi, S. hirsuta, S. hominis, S. fusiformis, Neospora caninum, Toxoplasma gondii, Cryptosporidium sp., Eimeria cylindrica, E. subspherica, E. bovis, E. zuernii, E. canadensis, E. ellipsoidalis, E. alabamensis, E. bukidnonensis, E. auburnensis, E. pellita, E. brasiliensis, Babesia divergens), 4 trematodes species (Dicrocoelium dendriticum, Fasciola hepatica, Parafasciolopsis fasciolaemorpha, Paramphistomum cervi), 4 cestodes species (Taenia hydatigena larvae, Moniezia benedeni, M. expansa, Moniezia sp.), 43 nematodes species (Bunostomum trigonocephalum, B. phlebotomum, Chabertia ovina, Oesophagostomum radiatum, O. venulosum, Dictyocaulus filaria, D.viviparus, Nematodirella alcidis, Nematodirus europaeus, N. helvetianus, N. roscidus, N. filicollis, N. spathiger, Cooperia oncophora, C. pectinata, C. punctata, C. surnabada, Haemonchus contortus, Mazamastrongylus dagestanicus, Ostertagia lyrata, O. ostertagi, O. antipini, O. leptospicularis, O. kolchida, O. circumcincta, O. trifurcata, Spiculopteragia boehmi, S. mathevossiani, S. asymmetrica, Trichostrongylus axei, T. askivali, T. capricola, T. vitrinus, Ashworthius sidemi, Onchocerca lienalis, O. gutturosa, Setaria labiatopapillosa, Gongylonema pulchrum, Thelazia gulosa, T. skrjabini, T. rhodesi, Aonchotheca bilobata, Trichuris ovis), 7 mites (Demodex bisonianus, D. bovis, Demodex sp., Chorioptes bovis, Psoroptes equi, P. ovis, Sarcoptes scabiei), 4 Ixodidae ticks (Ixodes ricinus, I. persulcatus, I. hexagonus, Dermacentor reticulatus), 1 Mallophaga species (Bisonicola sedecimdecembrii), 1 Anoplura (Haematopinus eurysternus), and 2 Hippoboscidae flies (Lipoptena cervi, Melophagus ovinus). There are few monoxenous parasites, many typical for cattle and many newly acquired from Cervidae.

  1. Evaluation of medicinal plant extracts and isolated compound epicatechin from Ricinus communis against Paramphistomum cervi.

    PubMed

    Zahir, Abdul Abduz; Rahuman, Abdul Abdul; Bagavan, Asokan; Geetha, Kannappan; Kamaraj, Chinnaperumal; Elango, Gandhi

    2012-10-01

    The purpose of this study is to determine the efficacies of hexane, chloroform, ethyl acetate, acetone, and methanol leaf extracts of Euphorbia hirta L., Psidium guajava L., Ricinus communis L., Solanum trilobatum L., and Tridax procumbens L. against sheep fluke Paramphistomum cervi (Digenea: Paramphistomatidae). All plant extracts showed moderate effects after 24 h of exposure; however, the highest parasite mortality was found in the methanol extract of R. communis. In the present study, bioassay-guided fractionation of methanol extract of R. communis led to the separation and identification of epicatechin as a potential new compound (LC(50) = 31.2; LC(90) = 105.0 ppm) against P. cervi. The structures were established from infrared, ultraviolet, (1)H-nuclear magnetic resonance (NMR), (13)C-NMR, and mass spectral data which confirmed the identification of the compound epicatechin from R. communis. Results of this study showed that the methanol extract of R. communis may be considered as a potent source and epicatechin as a new natural parasitic agent.

  2. Parasites

    MedlinePlus

    ... Where to Find Further Information on Parasitic Diseases Public Health Image Library Freedom of Information Act (FOIA) Explore Parasites A-Z Index Parasites Glossary Education and Training Healthy Water Travelers Health Laboratory ... Science Parasites About Parasites Animals ...

  3. Review of Cervi Cornu Parvum Pharmacopuncture in Korean Medicine

    PubMed Central

    Lee, Dong-Jin; Hwangbo, Min; Kwon, Kang; Seo, Hyung-Sik

    2013-01-01

    Objective: The endpoint of this review is to investigate existing studies of Cervi cornu parvum(CCP) pharmacopuncture within Korean medicine journals in order to present a better research method in the future. Methods: We searched all the papers through six Korean electrical databases that included the title of " Cervi cornu parvum pharmacopuncture" or " Cervi cornu parvum aqua-acupuncture". Articles that had been published until December 2012 were largely divided into experimental studies and clinical studies. Results: Fifty-three (53) experimental studies and six clinical studies were found. The number of published articles has been constantly increasing. Many of the experimental studies demonstrated anti-inflammatory effects for arthritis, and most of the clinical studies dealt with musculoskeletal problems. Conclusion: Various therapeutically significant effects of the CCP pharmacopuncture have been found through this review; however, more systematic clinical studies on the CCP pharmacopuncture seem to be necessary to substantially support its clinical effects. PMID:25780662

  4. Congenital Filariasis Caused by Setaria bidentata (Nematoda: Filarioidea) in the Red Brocket Deer (Mazama americana).

    PubMed

    Gomez-Puerta, Luis A; Mayor, Pedro

    2017-02-01

    The filarial nematode Setaria bidentata was found in 10 of 31 fetuses of the red brocket deer ( Mazama americana ) from the Loreto region of the Peruvian Amazon. A total of 25 specimens were collected and morphologically identified as S. bidentata. Filarial nematodes were found in the peritoneal cavity of 9 deer fetuses and the thoracic cavity of 1 fetus. Most specimens were adult stage. In this report, we provide morphometric data for these filarial specimens. This is the first study to demonstrate prenatal S. bidentata infection in cervid fetuses. Also, the finding of S. bidentata in Peru expands the geographic range of this parasite.

  5. The effects of an abundant ectoparasite, the deer ked (Lipoptena cervi), on the health of moose (Alces alces) in Finland.

    PubMed

    Paakkonen, Tommi; Mustonen, Anne-Mari; Käkelä, Reijo; Laaksonen, Sauli; Solismaa, Milla; Aho, Jari; Puukka, Katri; Nieminen, Petteri

    2012-09-01

    The deer ked (Lipoptena cervi, Diptera, Hippoboscidae) is a haematophagous parasitic fly of the moose (Alces alces) and other cervids, and it is very common in southern and central parts of Finland. The aim of this study was to determine how the intensive parasitism caused by the deer ked affects the health and welfare of the moose. Moose blood samples (n = 78) were collected from deer ked-infested and ked-free regions at 62-68° N and analysed for haematology and clinical chemistry. In addition, tissue samples of moose (n = 23) were collected from a deer ked-infested region at 62° N to determine how the parasite load correlates to several physiological variables of the host. The differences in the blood and plasma values between the deer ked-free and ked-infested animals were minor. In the infested regions, the moose had higher mean corpuscular haemoglobin concentrations unlikely to have been caused by the parasitism. The intensities of deer keds had no consistent correlations with the values of plasma clinical chemistry, endocrinology, amino acids, tissue enzyme activities or body energy stores. However, the hepatic percentages of several individual n-3 polyunsaturated fatty acids (PUFA) and the n-3 PUFA sum correlated inversely with the intensity and density of deer keds. Although a wide array of physiological variables was determined, only minor effects caused by the heavy deer ked parasitism could be detected, suggesting that the moose might tolerate this parasite relatively well.

  6. Reference genome sequence of the model plant Setaria

    SciTech Connect

    Bennetzen, Jeffrey L; Yang, Xiaohan; Ye, Chuyu; Tuskan, Gerald A

    2012-01-01

    We generated a high-quality reference genome sequence for foxtail millet (Setaria italica). The {approx}400-Mb assembly covers {approx}80% of the genome and >95% of the gene space. The assembly was anchored to a 992-locus genetic map and was annotated by comparison with >1.3 million expressed sequence tag reads. We produced more than 580 million RNA-Seq reads to facilitate expression analyses. We also sequenced Setaria viridis, the ancestral wild relative of S. italica, and identified regions of differential single-nucleotide polymorphism density, distribution of transposable elements, small RNA content, chromosomal rearrangement and segregation distortion. The genus Setaria includes natural and cultivated species that demonstrate a wide capacity for adaptation. The genetic basis of this adaptation was investigated by comparing five sequenced grass genomes. We also used the diploid Setaria genome to evaluate the ongoing genome assembly of a related polyploid, switchgrass (Panicum virgatum).

  7. Reference genome sequence of the model plant Setaria

    SciTech Connect

    Bennetzen, Jeffrey L; Schmutz, Jeremy; Wang, Hao; Percifield, Ryan; Hawkins, Jennifer; Pontaroli, Ana C.; Estep, Matt; Feng, Liang; Vaughn, Justin N; Grimwood, Jane; Jenkins, Jerry; Barry, Kerrie; Lindquist, Erika; Hellsten, Uffe; Deshpande, Shweta; Wang, Xuewen; Wu, Xiaomei; Mitros, Therese; Triplett, Jimmy; Yang, Xiaohan; Ye, Chuyu; Mauro-Herrera, Margarita; Wang, Lin; Li, Pinghua; Sharma, Manoj; Sharma, Rita; Ronald, Pamela; Panaud, Olivier; Kellogg, Elizabeth A.; Brutnell, Thomas P.; Doust, Andrew N.; Tuskan, Gerald A; Rokhsar, Daniel; Devos, Katrien M

    2012-01-01

    We generated a high-quality reference genome sequence for foxtail millet (Setaria italica). The ~400-Mb assembly covers ~80% of the genome and >95% of the gene space. The assembly was anchored to a 992-locus genetic map and was annotated by comparison with >1.3 million expressed sequence tag reads. We produced more than 580 million RNA-Seq reads to facilitate expression analyses. We also sequenced Setaria viridis, the ancestral wild relative of S. italica, and identified regions of differential single-nucleotide polymorphism density, distribution of transposable elements, small RNA content, chromosomal rearrangement and segregation distortion. The genus Setaria includes natural and cultivated species that demonstrate a wide capacity for adaptation. The genetic basis of this adaptation was investigated by comparing five sequenced grass genomes. We also used the diploid Setaria genome to evaluate the ongoing genome assembly of a related polyploid, switchgrass (Panicum virgatum).

  8. Hair-loss epizootic in moose (Alces alces) associated with massive deer ked (Lipoptena cervi) infestation.

    PubMed

    Madslien, Knut; Ytrehus, Bjørnar; Vikøren, Turid; Malmsten, Jonas; Isaksen, Ketil; Hygen, Hans Olav; Solberg, Erling J

    2011-10-01

    Deer keds (Lipoptena cervi) are blood-sucking flies in the family Hippoboscidae; moose (Alces alces) are their main host in Scandinavia. There are no detailed reports of the negative impacts of deer keds on moose. In 2006 and 2007, hunters in southeastern Norway and midwestern Sweden found several moose cadavers with severe alopecia; numerous moose had extensive hair loss. Between February 2006 and June 2007, materials from 23 moose were submitted for laboratory examination and large numbers of deer keds were found in the coat of most animals. The body condition of the moose varied but was poor in animals with severe alopecia. The findings of enormous numbers of deer keds in the coat of the majority of the affected animals and a consistent histologic image (acute to chronic, multifocal to coalescing, eosinophilic to lymphocytic dermatitis), concurrent with the absence of any other lesions, trace element deficiencies, or dermal infections which are known to cause alopecia, suggest that the hair-loss epizootic was linked to massive infestations with deer keds. The emergence of this hair-loss syndrome implies that the dynamics between parasite and host have been disrupted by a currently unknown environmental or ecological factor. A high moose density, combined with extraordinarily mild weather June 2006-June 2007 and a particularly long period with the absence of night-frost in autumn of 2006, may have been ideal for deer ked development, survival, and optimal host acquisition.

  9. Salt licks do not increase local densities of the deer ked, Lipoptena cervi, an abundant ectoparasite of cervids.

    PubMed

    Paakkonen, T; Nieminen, P; Roininen, H; Mustonen, A-M

    2014-09-01

    The deer ked, Lipoptena cervi (Diptera: Hippoboscidae), is a common ectoparasite of the moose, Alces alces (Artiodactyla: Cervidae). Salt licks are widely used to manipulate moose movements to prevent damage to saplings and traffic accidents. They may cause moose to gather in small areas, which could create aggregates of deer ked pupae as the parasite is a short-distance flyer and its dispersion depends on its hosts. We investigated whether the population density of flying deer keds could be influenced by manipulating salt licks and how environmental variables affect parasite density. Densities were estimated in 40 experimental sites with four treatments (no salt licks, introduced salt licks, removed salt licks, permanent salt licks) in September during 2007-2010. Forest edges, mixed forests on mineral soil and coniferous forests on peat soil were the habitats with high numbers of parasites. The manipulation of salt licks seemed to be ineffective in reducing the density of deer keds as the only factor to show statistical significance with parasite numbers in the mixed-model analysis was year of determination. Annual deer ked densities correlated with the abundance of moose in the region. Moreover, high spring and summer temperatures seemed to increase the numbers of flying imagos.

  10. [Experimental infection of 2 species of laboratory rodents with invasive larvae of Elaphostrongylus cervi (Nematoda, Metastrongyloidea)].

    PubMed

    Demiaszkiewicz, A W

    1989-01-01

    Single doses (from 300 to 1000 larvi per an animal) of invasive larvae E. cervi Cameron, 1931, obtained from experimentally infected snails Helix pomatia L. were given to 17 guinea pigs and 17 golden hamsters. Clinical nervous symptoms in the form of paresis and paralysis of limbs occurred only in the guinea pigs which were given a dose of 1000 larvi. These animals died in the period from the 75th to 117th day of infection. From their central nervous system single adult males and females of E. cervi were isolated. In the lungs and mesenteries of 2 dead pigs live larvae of E. cervi were found. This fact proves that the guinea pig can fulfil the role of a final and a paratenic host of E. cervi. No clinical symptoms were noticed in any hamster. In hamsters dissected on the 7th day of infection live larvae of E. cervi were found in the mesentery and in the fleshy part of the diaphgram. After 14 days the larvae found both in the mesentery and in the diaphragm were dead and surrounded by cellular infiltration. A strong tissue reaction of the hamster after the administration of E. cervi larvae is responsible for the larvae destruction and resorption.

  11. Phytolith analysis for differentiating between foxtail millet (Setaria italica) and green foxtail (Setaria viridis).

    PubMed

    Zhang, Jianping; Lu, Houyuan; Wu, Naiqin; Yang, Xiaoyan; Diao, Xianmin

    2011-05-06

    Foxtail millet (Setaria italica) is one of the oldest domesticated cereal crops in Eurasia, but identifying foxtail millets, especially in charred grains, and differentiating it from its wild ancestor, green foxtail (Setaria viridis), in the archaeobotanical remains, is still problematic. Phytolithic analysis provides a meaningful method for identifying this important crop. In this paper, the silicon structure patterns in the glumes, lemmas, and paleas from inflorescence bracts in 16 modern plants of foxtail millet and green foxtail from China and Europe are examined using light microscopy with phase-contrast and a microscopic interferometer. Our research shows that the silicon structure of ΩIII from upper lemmas and paleas in foxtail millet and green foxtail can be correspondingly divided into two groups. The size of ΩIII type phytolith of foxtail millet is bigger than that from green foxtail. Discriminant function analysis reveals that 78.4% of data on foxtail millet and 76.9% of data on green foxtail are correctly classified. This means certain morphotypes of phytoliths are relatively reliable tools for distinguishing foxtail millet from green foxtail. Our results also revealed that the husk phytolith morphologies of foxtail millets from China and Eastern Europe are markedly different from those from Western Europe. Our research gives a meaningful method of separating foxtail millet and green foxtail. The implications of these findings for understanding the history of foxtail millet domestication and cultivation in ancient civilizations are significant.

  12. Spike-dip transformation of Setaria viridis.

    PubMed

    Saha, Prasenjit; Blumwald, Eduardo

    2016-04-01

    Traditional method of Agrobacterium-mediated transformation through the generation of tissue culture had limited success for Setaria viridis, an emerging C4 monocot model. Here we present an efficient in planta method for Agrobacterium-mediated genetic transformation of S. viridis using spike dip. Pre-anthesis developing spikes were dipped into a solution of Agrobacterium tumefaciens strain AGL1 harboring the β-glucuronidase (GUS) reporter gene driven by the cauliflower mosaic virus 35S (CaMV35S) promoter to standardize and optimize conditions for transient as well as stable transformations. A transformation efficiency of 0.8 ± 0.1% was obtained after dipping of 5-day-old S3 spikes for 20 min in Agrobacterium cultures containing S. viridis spike-dip medium supplemented with 0.025% Silwet L-77 and 200 μm acetosyringone. Reproducibility of this method was demonstrated by generating stable transgenic lines expressing β-glucuronidase plus (GUSplus), green fluorescent protein (GFP) and Discosoma sp. red fluorescent protein (DsRed) reporter genes driven by either CaMV35S or intron-interrupted maize ubiquitin (Ubi) promoters from three S. viridis genotypes. Expression of these reporter genes in transient assays as well as in T1 stable transformed plants was monitored using histochemical, fluorometric GUS activity and fluorescence microscopy. Molecular analysis of transgenic lines revealed stable integration of transgenes into the genome, and inherited transgenes expressed in the subsequent generations. This approach provides opportunities for the high-throughput transformation and potentially facilitates translational research in a monocot model plant.

  13. Population genetics of Setaria viridis, a new model system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An extensive survey of the standing genetic variation in natural populations is among the priority steps in developing a species into a model system. In recent years, green foxtail (Setaria viridis), along with its domesticated form foxtail millet (S. italica), has rapidly become a promising new mod...

  14. The Mitochondrial Genome of Paramphistomum cervi (Digenea), the First Representative for the Family Paramphistomidae

    PubMed Central

    Lou, Zhong-Zi; Li, Li; Blair, David; Yin, Hong; Cai, Jin-Zhong; Dai, Xue-Ling; Lei, Meng-Tong; Zhu, Xing-Quan; Cai, Xue-Peng; Jia, Wan-Zhong

    2013-01-01

    We determined the complete mitochondrial DNA (mtDNA) sequence of a fluke, Paramphistomum cervi (Digenea: Paramphistomidae). This genome (14,014 bp) is slightly larger than that of Clonorchis sinensis (13,875 bp), but smaller than those of other digenean species. The mt genome of P. cervi contains 12 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes and 2 non-coding regions (NCRs), a complement consistent with those of other digeneans. The arrangement of protein-coding and ribosomal RNA genes in the P. cervi mitochondrial genome is identical to that of other digeneans except for a group of Schistosoma species that exhibit a derived arrangement. The positions of some transfer RNA genes differ. Bayesian phylogenetic analyses, based on concatenated nucleotide sequences and amino-acid sequences of the 12 protein-coding genes, placed P. cervi within the Order Plagiorchiida, but relationships depicted within that order were not quite as expected from previous studies. The complete mtDNA sequence of P. cervi provides important genetic markers for diagnostics, ecological and evolutionary studies of digeneans. PMID:23990943

  15. Sex, age, spleen size, and kidney fat of red deer relative to infection intensities of the lungworm Elaphostrongylus cervi.

    PubMed

    Vicente, J; Pérez-Rodríguez, L; Gortazar, C

    2007-07-01

    We analyzed the relationships among spleen size, body condition (measured as kidney fat), and larval counts of the nematode Elaphostrongylus cervi in red deer (Cervus elaphus). The aim was to investigate the interaction between host body condition and intensity of infection with parasites. As red deer are highly polygynous, we also tested whether these relationships varied with sex and age of the hosts. Kidney fat and spleen size were positively correlated in subadults (2-3 years old) and adults (>3 years old), but not in calves (<1 year old) or yearlings (1-2 years old). Spleen size was negatively associated with nematode load in subadult females and in adult males. These two age classes are potentially the most nutritionally stressed, as subadult hinds are still growing and often engaging in rearing their first calf, and adult stags were sampled just after the rut, which is recognized as a substantial energy drain in this age-sex class, as they compete to hold females during the mating season. Body condition related negatively to parasite count only in adult males. In the context of red deer life history, these findings suggest that spleen size is dependent on body condition and that it could be affected by variation in resource partitioning among immune defense, growth, and reproductive effort in red deer. For the first time in a wild mammal, the spleen mass is shown to be positively related to body condition and negatively related to parasite infection. We conclude that elucidating whether spleen mass reflects immune defense investment or a measure of general body condition should contribute to understanding topical issues in mammal ecology.

  16. Sex, age, spleen size, and kidney fat of red deer relative to infection intensities of the lungworm Elaphostrongylus cervi

    NASA Astrophysics Data System (ADS)

    Vicente, J.; Pérez-Rodríguez, L.; Gortazar, C.

    2007-07-01

    We analyzed the relationships among spleen size, body condition (measured as kidney fat), and larval counts of the nematode Elaphostrongylus cervi in red deer ( Cervus elaphus). The aim was to investigate the interaction between host body condition and intensity of infection with parasites. As red deer are highly polygynous, we also tested whether these relationships varied with sex and age of the hosts. Kidney fat and spleen size were positively correlated in subadults (2-3 years old) and adults (>3 years old), but not in calves (<1 year old) or yearlings (1-2 years old). Spleen size was negatively associated with nematode load in subadult females and in adult males. These two age classes are potentially the most nutritionally stressed, as subadult hinds are still growing and often engaging in rearing their first calf, and adult stags were sampled just after the rut, which is recognized as a substantial energy drain in this age-sex class, as they compete to hold females during the mating season. Body condition related negatively to parasite count only in adult males. In the context of red deer life history, these findings suggest that spleen size is dependent on body condition and that it could be affected by variation in resource partitioning among immune defense, growth, and reproductive effort in red deer. For the first time in a wild mammal, the spleen mass is shown to be positively related to body condition and negatively related to parasite infection. We conclude that elucidating whether spleen mass reflects immune defense investment or a measure of general body condition should contribute to understanding topical issues in mammal ecology.

  17. ANTI-PARASITIC ACTIVITY OF CERTAIN INDIGEOUS PLANTS

    PubMed Central

    Mathai, Annie; Devi, K.S.

    1992-01-01

    The antiparasitic activity of certain indigenous plant extracts was tested against the model bovine filarial parasite Setaria digitata. Among the plants tested, the extracts of Strebulus asper was found to be most effective. The chloroform and other phase of the organic solvents showed most activity indicating that the active compound may be a non polar substance having low molecular weight. PMID:22556601

  18. Setaria equina: in vivo effect of diethylcarbamazine citrate on microfilariae in albino rats.

    PubMed

    El-Shahawi, G A; Abdel-Latif, M; Saad, A H; Bahgat, M

    2010-12-01

    Although diethylcarbamazine citrate (DEC) is successful drug in eliminating human filariasis, yet, its mode of action is still debatable. Herein, the effect of DEC to treat albino rats infected with the animal filarial parasite Setaria equina was tested. Microfilarial (mf) counts and sections from liver, lung, kidney as well as spleen were investigated at different time points after treatment by light microscopy. After 45 and 300min of treatment, a significant decrease in blood mf was observed accompanied by adherence of degenerated mf to both kupffer cells and leukocyte in liver sections. In lung sections, loss of sheath was observed at 45min, while degeneration was observed at later time points. In kidney sections, more mf counts and less matrix were observed in the glomeruli at all time points after treatment. Degenerated mf were observed in spleen sections only at, late time point, 480min after treatment. In conclusion, one of the possible mechanisms by which DEC reduces blood microfilarial count is trapping larvae in organs and killing them through cellular adherence.

  19. Bartonella infections in deer keds (Lipoptena cervi) and moose (Alces alces) in Norway.

    PubMed

    Duodu, Samuel; Madslien, Knut; Hjelm, Eva; Molin, Ylva; Paziewska-Harris, Anna; Harris, Philip D; Colquhoun, Duncan J; Ytrehus, Bjørnar

    2013-01-01

    Infections with Bartonella spp. have been recognized as emerging zoonotic diseases in humans. Large knowledge gaps exist, however, relating to reservoirs, vectors, and transmission of these bacteria. We describe identification by culture, PCR, and housekeeping gene sequencing of Bartonella spp. in fed, wingless deer keds (Lipoptena cervi), deer ked pupae, and blood samples collected from moose, Alces alces, sampled within the deer ked distribution range in Norway. Direct sequencing from moose blood sampled in a deer ked-free area also indicated Bartonella infection but at a much lower prevalence. The sequencing data suggested the presence of mixed infections involving two species of Bartonella within the deer ked range, while moose outside the range appeared to be infected with a single species. Bartonella were not detected or cultured from unfed winged deer keds. The results may indicate that long-term bacteremia in the moose represents a reservoir of infection and that L. cervi acts as a vector for the spread of infection of Bartonella spp. Further research is needed to evaluate the role of L. cervi in the transmission of Bartonella to animals and humans and the possible pathogenicity of these bacteria for humans and animals.

  20. Detection and molecular characterization of the mosquito-borne filarial nematode Setaria tundra in Danish roe deer (Capreolus capreolus).

    PubMed

    Enemark, Heidi Larsen; Oksanen, Antti; Chriél, Mariann; le Fèvre Harslund, Jakob; Woolsey, Ian David; Al-Sabi, Mohammad Nafi Solaiman

    2017-04-01

    Setaria tundra is a mosquito-borne filarial nematode of cervids in Europe. It has recently been associated with an emerging epidemic disease causing severe morbidity and mortality in reindeer and moose in Finland. Here, we present the first report of S. tundra in six roe deer (Capreolus capreolus) collected between October 2010 and March 2014 in Denmark. The deer originated from various localities across the country: the eastern part of the Jutland peninsular and four locations on the island Zealand. With the exception of one deer, with parasites residing in a transparent cyst just under the liver capsule, worms (ranging from 2 to >20/deer) were found free in the peritoneal cavity. The worms were identified as S. tundra by morphological examination and/or molecular typing of the mitochondrial 12S rRNA and cox1 genes, which showed 99.1-99.8% identity to previously published S. tundra isolates from Europe. Roe deer are generally considered as asymptomatic carriers and their numbers in Denmark have increased significantly in recent decades. In light of climatic changes which result in warmer, more humid weather in Scandinavia greater numbers of mosquitoes and, especially, improved conditions for development of parasite larvae in the mosquito vectors are expected, which may lead to increasing prevalence of S. tundra. Monitoring of this vector-borne parasite may thus be needed in order to enhance the knowledge of factors promoting its expansion and prevalence as well as predicting disease outbreaks.

  1. Activity of buparvaquone against Theileria cervi in white-tailed deer.

    PubMed

    Mitema, E S; Kocan, A A; Mukolwe, S W; Sangiah, S; Sherban, D

    1991-01-01

    Buparvaquone, a naphthoquinone with known efficacy against Theileria parva parva in cattle, was tested for activity against Theileria cervi piroplasms in both an in vitro culture system and in vivo in experimentally infected white-tailed deer. The in vitro data showed a significant decrease in the incorporation of 3H-hypoxanthine by infected red blood cells treated with buparvaquone when compared to that seen with imidocarb and chloroquine treatment. In both intact and splenectomized deer treated with buparvaquone (2.5 mg kg-1) a gradual decrease in piroplasm parasitaemia was observed following treatment. However, in the splenectomized deer, parasitaemia levels returned to near pretreatment values after approximately 2 weeks.

  2. Effect of diethylcarbamazine citrate and Setaria equina excretory-secretory material on rat hepatocellular carcinoma.

    PubMed

    Abdel-Latif, Mahmoud; Sakran, Thabet; El-Shahawi, Gamal; El-Fayoumi, Hoda; El-Mallah, Al-Mahy

    2014-12-01

    Diethylcarbamazine citrate (DEC) has been known for its efficacy to eradicate bancroftian filariasis in Egypt and other countries in the world. One of the known effects was to decrease the level of circulating filarial antigen in the patient's serum. The target of this study was to examine the effect of DEC, excretory-secretory (ES) material from the filarial parasite Setaria equina or a combination of both on the status of oxidative stress and pathogenesis of rat hepatocellular carcinoma (HCC) induced by diethylnitrosamine and 2-acetylaminofluorene. This could be tested in vitro using nitroblue tetrazolium reduction test for measuring the level of superoxide anion (O₂(•-)) released from rat peritoneal macrophages. For in vivo test, a single dose before induction of carcinogenesis or continually repeated doses with DEC, ES or DEC + ES was used. Exposure of macrophages to ES could lead to a significant decrease (p < 0.01) in O₂(•-) release, while DEC (200 μM) could modulate such effect with significant increase (p < 0.05). Pathogenesis of liver cancer and treatment were evaluated using histological investigation, level of antioxidant and liver function enzymes. Repeated ES doses could increase the activity of antioxidant enzymes, especially the catalase enzyme and show a protective effect on liver architecture. DEC could modulate the later effects when combined with ES. No significant effect on the liver function enzymes after treatment was observed. Nuclear factor κB was found to be localized only in the cytoplasm after single and repeated treatments with ES. This study could indicate the effect of S. equina ES as antioxidant against rat HCC, while DEC could modulate such effect when combined with it.

  3. A Versatile Phenotyping System and Analytics Platform Reveals Diverse Temporal Responses to Water Availability in Setaria.

    PubMed

    Fahlgren, Noah; Feldman, Maximilian; Gehan, Malia A; Wilson, Melinda S; Shyu, Christine; Bryant, Douglas W; Hill, Steven T; McEntee, Colton J; Warnasooriya, Sankalpi N; Kumar, Indrajit; Ficor, Tracy; Turnipseed, Stephanie; Gilbert, Kerrigan B; Brutnell, Thomas P; Carrington, James C; Mockler, Todd C; Baxter, Ivan

    2015-10-05

    Phenotyping has become the rate-limiting step in using large-scale genomic data to understand and improve agricultural crops. Here, the Bellwether Phenotyping Platform for controlled-environment plant growth and automated multimodal phenotyping is described. The system has capacity for 1140 plants, which pass daily through stations to record fluorescence, near-infrared, and visible images. Plant Computer Vision (PlantCV) was developed as open-source, hardware platform-independent software for quantitative image analysis. In a 4-week experiment, wild Setaria viridis and domesticated Setaria italica had fundamentally different temporal responses to water availability. While both lines produced similar levels of biomass under limited water conditions, Setaria viridis maintained the same water-use efficiency under water replete conditions, while Setaria italica shifted to less efficient growth. Overall, the Bellwether Phenotyping Platform and PlantCV software detected significant effects of genotype and environment on height, biomass, water-use efficiency, color, plant architecture, and tissue water status traits. All ∼ 79,000 images acquired during the course of the experiment are publicly available.

  4. Setaria viridis floral-dip: A simple and rapid Agrobacterium-medicated transformation method

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Setaria viridis was recently described as a new monocotyledonous model species for C4 photosynthesis research and genetic transformation. It has biological attributes (rapid life cycle, small genome, diploid, short stature and simple growth requirements) that make it suitable for use as a model plan...

  5. The importance of parasite life history and host density in predicting the impact of infections in red deer.

    PubMed

    Vicente, Joaquín; Höfle, Ursula; Fernández-De-Mera, Isabel García; Gortazar, Christian

    2007-07-01

    We studied a macroparasite (Elaphostrongylus cervi, Nematoda) and a microparasite infection (tuberculosis, TB) in red deer (Cervus elaphus) across different populations where managers manipulated host condition, density and aggregation by providing supplemental food. We aimed to test whether and, if so, how persistence and transmission of both parasites differentially varied as host body condition and population density varied. We took account of sex, as red deer life history greatly concerns sex-related traits. Changes in host factors had different consequences for the spread of each parasite type. Individual presence of tuberculosis was positively associated with host density, whereas E. cervi abundance negatively related to host density and enhanced body condition. There was lack of body condition density dependence; and body condition was mainly dependent on the amount of supplemental food provided, but also on habitat quality descriptors. Overall, our results suggest that body condition was improved at the cost of increased host contact rates, which implied an ecological trade-off between acquiring resources to cope with E. cervi, a macroparasite, and concurrent exposure to mycobacteria. By the simultaneous study of both infections, this research suggests that the effects of changes in host number and population structure on disease spread and persistence need to take into account variation in life histories of the parasites. These findings also raise concern about the ecological consequences of diseases and management of wildlife on host life history.

  6. Cornu cervi pantotrichum supplementation improves exercise performance and protects against physical fatigue in mice.

    PubMed

    Huang, Chi-Chang; Chen, Yi-Ming; Kan, Nai-Wen; Chao, Hui-Ling; Ho, Chin-Shan; Hsu, Mei-Chich

    2014-04-15

    Cornu cervi pantotrichum (CCP) is a well-known yang-invigorating agent used in traditional Chinese medicine that can nourish the blood, tonify qi, and invigorate bones and tendons with multifunctional bioactivities. However, evidence on the effects of CCP on exercise performance and physical fatigue is limited. We evaluated the potential beneficial effects of ethanolic extract from CCP on ergogenic and antifatigue functions following a physiological challenge. Male ICR mice from four groups (n=8 per group) were orally administered CCP for 14 days at 0, 2054, and 4108 mg/kg/day, and were respectively designated as the vehicle, CCP-1X, and CCP-2X groups. The physical performance and antifatigue function were evaluated using forelimb grip strength and exhaustive swimming time as well as serum levels of lactate, ammonia, glucose, and creatine kinase after a 15-min swimming exercise. The results indicated that CCP-1X supplementation significantly improved grip strength; reduced fatigue-associated biochemical indices, including lactate and ammonia levels; and ameliorated skeletal muscle injury induced by acute exercise challenge. A trend analysis revealed that CCP supplementation significantly increased grip strength and dose-dependently reduced serum alkaline phosphatase, uric acid, triacylglycerol, and glucose levels in healthy mice. Therefore, CCP is a potential agent with an antifatigue pharmacological effect.

  7. Differential Gene Expression in Foxtail Millet during Incompatible Interaction with Uromyces setariae-italicae

    PubMed Central

    Dong, Li; Bai, Hui; Quan, Jian Zhang; Liu, Lei; Dong, Zhi-Ping

    2015-01-01

    Foxtail millet (Setaria italica) is an important food and fodder grain crop that is grown for human consumption. Production of this species is affected by several plant diseases, such as rust. The cultivar Shilixiang has been identified as resistant to the foxtail millet rust pathogen, Uromyces setariae-italicae. In order to identify signaling pathways and genes related to the plant’s defense mechanisms against rust, the Shilixiang cultivar was used to construct a digital gene expression (DGE) library during the interaction of foxtail millet with U. setariae-italicae. In this study, we determined the most abundant differentially expressed signaling pathways of up-regulated genes in foxtail millet and identified significantly up-regulated genes. Finally, quantitative real-time polymerase chain reaction (qRT-PCR) analysis was used to analyze the expression of nine selected genes, and the patterns observed agreed well with DGE analysis. Expression levels of the genes were also compared between a resistant cultivar Shilixiang and a susceptible cultivar Yugu-1, and the result indicated that expression level of Shilixiang is higher than that of Yugu-1. This study reveals the relatively comprehensive mechanisms of rust-responsive transcription in foxtail millet. PMID:25885767

  8. Circulation of Dirofilaria repens, Setaria tundra, and Onchocercidae species in Hungary during the period 2011-2013.

    PubMed

    Kemenesi, Gábor; Kurucz, Kornélia; Kepner, Anett; Dallos, Bianka; Oldal, Miklós; Herczeg, Róbert; Vajdovics, Péter; Bányai, Krisztián; Jakab, Ferenc

    2015-11-30

    Dirofilaria repens and recently Dirofilaria immitis are known to be endemic in Hungary. Since there is no related research on Dirofilaria carrier mosquito species from Hungary, we conducted a three-year mosquito surveillance study between 2011 and 2013. During the study period we examined 23,139 female mosquitoes with a generic filaria-specific TaqMan PCR assay, and characterized them by sequencing a 500 bp segment of 12S rRNA. An important result of our study was the detection of Setaria tundra and D. repens along with an unidentified Onchocercidae nematode. D. repens is known to be endemic in Hungary, however, the detection of S. tundra in all sampling sites throughout the study period indicates for the first time the endemicity of this parasite in Hungary. The Onchocercidae sp. nematode showed 95% nucleotide identity with previously detected unidentified nematodes from Germany, indicating a broader geographical distribution of this nematode in Europe. D. immitis specific DNA was not detected among the screened mosquitoes in this study. Here we report 11 mosquito species as potential vector organisms for local filarial infections, including Aedes vexans, Ochlerotatus annulipes, Ochlerotatus sticticus, Coquillettidia richiardii, Anopheles hyrcanus and Ochlerotatus rusticus. Dirofilaria development unit was calculated and the potential transmission period was estimated, which ranged between 65 and 113 days between sampling seasons. A relatively high infection rate (36.8%) was identified, which is a notable finding for veterinary and human health professionals. Moreover, the results of our study widen the group of possible mosquito vector species for D. repens and S. tundra in Central Europe.

  9. Cornu cervi pantotrichum supplementation improves physiological adaptions during intensive endurance training

    PubMed Central

    HUANG, Wen-Ching; HUANG, Chi-Chang; CHUANG, Hsiao-Li; CHIU, Chien-Chao; CHEN, Wen-Chyuan; HSU, Mei-Chich

    2017-01-01

    Cornu cervi pantotrichum (CCP), used in traditional Chinese medicine, is a well-known yang-invigorating agent with multifunctional bioactivities. We previously showed, through an acute exercise challenge, that short-term CCP supplementation improved physical activities and fatigue-associated biochemical indices. Questions about the long-term effects of CCP treatment on exercise performance and physical fatigue, as well as safety, with intensive exercise training need further research. ICR-strain mice were randomly assigned to three groups: (1) sedentary control and vehicle treatment (SC); (2) exercise training with vehicle treatment (ET); and (3) ET with CCP treatment at 4,108 mg/kg/day (ET+CCP). We assessed the physical performance, body compositions, and serum levels of lactate, ammonia, glucose and creatine kinase (CK) after an acute exercise challenge. The ET and ET+CCP groups had significantly increased grip strength and endurance swimming time, and decreased serum lactate and ammonia levels after the acute exercise challenge than the SC group. Moreover, serum ammonia and CK levels in the ET+CCP group were significantly decreased when compared to that of the ET only group. In regard to the body composition, the ET+CCP group inhibits the decrease in fat tissue, and related biochemical changes induced by the high intensity endurance training CCP supplementation combined with high-intensity endurance exercise could significantly improve the physiological adaptions related to fatigue or energy consumption and maintain the fat composition when compared to treatment with training only. Therefore, CCP may potentially improve the physiological adaptions in intensive exercise training. PMID:28163267

  10. Cornu cervi pantotrichum Pharmacopuncture Solution Facilitate Hair Growth in C57BL/6 Mice

    PubMed Central

    Lee, Seon-Yong; Lee, Dong-Jin; Kwon, Kang; Lee, Chang-Hyun; Shin, Hyun Jong; Kim, Jai Eun; Ha, Ki-Tae; Jeong, Han-Sol

    2016-01-01

    Objectives: Cornu cervi pantotrichum (CCP) has been widely used in Korean and China, as an anti-fatigue, anti-aging, and tonic agent to enhance the functions of the reproductive and the immune systems. Because CCP has various growth factors that play important roles in the development of hair follicles, we examined whether CCP pharmacopuncture solution (CCPPS) was capable of promoting hair growth in an animal model. Methods: One day after hair depilation, CCPPS were topically applied to the dorsal skin of C57BL/6 mice once a day for 15 days. Hair growth activity was evaluated by using macro- and microscopic observations. Dorsal skin tissues were stained with hematoxylin and eosin. Expressions of bromodeoxyuridine (BrdU), proliferating cell nuclear antigen (PCNA), and fibroblast growth factor (FGF)-7 were examined by using immunohistochemical staining. A reverse transcription polymerase chain reaction (RT-PCR) analysis was also conducted to measure the messenger RNA (mRNA) expression of FGF-7. Results: CCPPS induced more active hair growth than normal saline. Histologic analysis showed enlargement of the dermal papilla, elongation of the hair shaft, and expansion of hair thickness in CCPPS treated mice, indicating that CCPPS effectively induced the development of anagen. CCPPS treatment markedly increased the expressions of BrdU and PCNA in the hair follicles of C57BL/6 mice. In addition, CCPPS up regulated the expression of FGF-7, which plays an important role in the development of hair follicles. Conclusion: These results reveal that CCPPS facilitates hair re-growth by proliferation of hair follicular cells and up-regulation of FGF-7 and suggest that CCPPS can potentially be applied as an alternative treatment for patients with alopecia. PMID:27386145

  11. Development and Genetic Control of Plant Architecture and Biomass in the Panicoid Grass, Setaria

    PubMed Central

    Mauro-Herrera, Margarita; Doust, Andrew N.

    2016-01-01

    The architecture of a plant affects its ability to compete for light and to respond to environmental stresses, thus affecting overall fitness and productivity. Two components of architecture, branching and height, were studied in 182 F7 recombinant inbred lines (RILs) at the vegetative, flowering and mature developmental stages in the panicoid C4 model grass system, Setaria. The RIL population was derived from a cross between domesticated S. italica (foxtail millet) and its wild relative S. viridis (green foxtail). In both field and greenhouse trials the wild parent was taller initially, started branching earlier, and flowered earlier, while the domesticated parent was shorter initially, but flowered later, producing a robust tall plant architecture with more nodes and leaves on the main culm and few or no branches. Biomass was highly correlated with height of the plant and number of nodes on the main culm, and generally showed a negative relationship with branch number. However, several of the RILs with the highest biomass in both trials were significantly more branched than the domesticated parent of the cross. Quantitative trait loci (QTL) analyses indicate that both height and branching are controlled by multiple genetic regions, often with QTL for both traits colocalizing in the same genomic regions. Genomic positions of several QTL colocalize with QTL in syntenic regions in other species and contain genes known to control branching and height in sorghum, maize, and switchgrass. Included in these is the ortholog of the rice SD-1 semi-dwarfing gene, which underlies one of the major Setaria height QTL. Understanding the relationships between height and branching patterns in Setaria, and their genetic control, is an important step to gaining a comprehensive knowledge of the development and genetic regulation of panicoid grass architecture. PMID:26985990

  12. Development and Genetic Control of Plant Architecture and Biomass in the Panicoid Grass, Setaria.

    PubMed

    Mauro-Herrera, Margarita; Doust, Andrew N

    2016-01-01

    The architecture of a plant affects its ability to compete for light and to respond to environmental stresses, thus affecting overall fitness and productivity. Two components of architecture, branching and height, were studied in 182 F7 recombinant inbred lines (RILs) at the vegetative, flowering and mature developmental stages in the panicoid C4 model grass system, Setaria. The RIL population was derived from a cross between domesticated S. italica (foxtail millet) and its wild relative S. viridis (green foxtail). In both field and greenhouse trials the wild parent was taller initially, started branching earlier, and flowered earlier, while the domesticated parent was shorter initially, but flowered later, producing a robust tall plant architecture with more nodes and leaves on the main culm and few or no branches. Biomass was highly correlated with height of the plant and number of nodes on the main culm, and generally showed a negative relationship with branch number. However, several of the RILs with the highest biomass in both trials were significantly more branched than the domesticated parent of the cross. Quantitative trait loci (QTL) analyses indicate that both height and branching are controlled by multiple genetic regions, often with QTL for both traits colocalizing in the same genomic regions. Genomic positions of several QTL colocalize with QTL in syntenic regions in other species and contain genes known to control branching and height in sorghum, maize, and switchgrass. Included in these is the ortholog of the rice SD-1 semi-dwarfing gene, which underlies one of the major Setaria height QTL. Understanding the relationships between height and branching patterns in Setaria, and their genetic control, is an important step to gaining a comprehensive knowledge of the development and genetic regulation of panicoid grass architecture.

  13. The Use of Maleic Hydrazide for Effective Hybridization of Setaria viridis

    PubMed Central

    Rizal, Govinda; Karki, Shanta; Garcia, Richard; Larazo, Nikki; Alcasid, Michael; Quick, William Paul

    2015-01-01

    An efficient method for crossing green foxtail (Setaria viridis) is currently lacking. S. viridis is considered to be the new model plant for the study of C4 system in monocots and so an effective crossing protocol is urgently needed. S. viridis is a small grass with C4-NADP (ME) type of photosynthesis and has the advantage of having small genome of about 515 Mb, small plant stature, short life cycle, multiple tillers, and profuse seed set, and hence is an ideal model species for research. The objectives of this project were to develop efficient methods of emasculation and pollination, and to speed up generation advancement. We assessed the response of S. viridis flowers to hot water treatment (48°C) and to different concentrations of gibberellic acid, abscisic acid, maleic hydrazide (MH), and kinetin. We found that 500 μM of MH was effective in the emasculation of S. viridis, whilst still retaining the receptivity of the stigma to pollination. We also report effective ways to accelerate the breeding cycle of S. viridis for research through the germination of mature as well as immature seeds in optimized culture media. We believe these findings will be of great interest to researchers using Setaria. PMID:25910193

  14. Genetic diversity and population structure of elite foxtail millet [Setaria italica (L.) P. Beauv.] germplasm in China

    Technology Transfer Automated Retrieval System (TEKTRAN)

    China is among the countries that have the most severe water deficiency. Due to its excellent drought tolerance, foxtail millet [Setaria italica (L.) P. Beauv.] has become one of the important cereal crops in China. Information on genetic diversity and population structure of foxtail millet may faci...

  15. Gastrointestinal parasites of working donkeys of Ethiopia.

    PubMed

    Getachew, M; Trawford, A; Feseha, G; Reid, S W J

    2010-01-01

    The general prevalence and population composition of gastrointestinal and pulmonary helminths of working donkeys were studied. For the purpose 2935 working donkeys were coprologically examined for nematode and cestode, and 215 donkeys for trematode infections. Seven donkeys that died due to various health problems or were euthanased on a welfare ground were necropsied and the parasites were recovered and identified to the species level. The study was conducted during the periods 1996-1999.Coprological examination revealed 99% strongyle, 80% Fasciola, 51% Parascaris, 30% Gastrodiscus, 11% Strongyloides westeri, 8% cestodes and 2% Oxyuris equi infection prevalence. Over 55% of donkeys had more than 1000 eggs per gram of faeces (epg). Forty two different species of parasites consisting of 33 nematodes, 3 trematodes, 3 cestodes and 3 arthropod larvae were identified from postmortem examined donkeys. Among the nematodes 17 species of Cyathostominae and 7 species of Strongylinae were identified. Other parasites identified include, Habronema muscae, Draschia megastoma, Trichostrongylus axei, Strongyloides westeri, Anoplocephala perfoliata, Anoplocephala magna, Anoplocephaloides (Paranoplocephala) mamillana, Parascaris equorum, Fasciola hepatica, Fasciola gigantica, Gastrodiscus aegyptiacus, Dictyocaulus arnfieldi, Oxyuris equi, Probstmayria vivipara, Gasterophilus intestinalis, Gasterophilus nasalis, Rhinoestrus uzbekistanicus and Setaria equina. This study revealed that working donkeys in Ethiopia are infected with a range of helminths and arthropod larvae, which are representatives of the important pathogenic parasites found in equids worldwide.

  16. Interacting parasites

    USGS Publications Warehouse

    Lafferty, Kevin D.

    2010-01-01

    Parasitism is the most popular life-style on Earth, and many vertebrates host more than one kind of parasite at a time. A common assumption is that parasite species rarely interact, because they often exploit different tissues in a host, and this use of discrete resources limits competition (1). On page 243 of this issue, however, Telfer et al. (2) provide a convincing case of a highly interactive parasite community in voles, and show how infection with one parasite can affect susceptibility to others. If some human parasites are equally interactive, our current, disease-by-disease approach to modeling and treating infectious diseases is inadequate (3).

  17. Parasites: Water

    MedlinePlus

    ... Tropical Diseases Laboratory Diagnostic Assistance [DPDx] Parasites Home Water Language: English Español (Spanish) Recommend on Facebook Tweet Share Compartir Parasites can live in natural water sources. When outdoors, treat your water before drinking ...

  18. Setaria viridis as a Model System to Advance Millet Genetics and Genomics

    PubMed Central

    Huang, Pu; Shyu, Christine; Coelho, Carla P.; Cao, Yingying; Brutnell, Thomas P.

    2016-01-01

    Millet is a common name for a group of polyphyletic, small-seeded cereal crops that include pearl, finger and foxtail millet. Millet species are an important source of calories for many societies, often in developing countries. Compared to major cereal crops such as rice and maize, millets are generally better adapted to dry and hot environments. Despite their food security value, the genetic architecture of agronomically important traits in millets, including both morphological traits and climate resilience remains poorly studied. These complex traits have been challenging to dissect in large part because of the lack of sufficient genetic tools and resources. In this article, we review the phylogenetic relationship among various millet species and discuss the value of a genetic model system for millet research. We propose that a broader adoption of green foxtail (Setaria viridis) as a model system for millets could greatly accelerate the pace of gene discovery in the millets, and summarize available and emerging resources in S. viridis and its domesticated relative S. italica. These resources have value in forward genetics, reverse genetics and high throughput phenotyping. We describe methods and strategies to best utilize these resources to facilitate the genetic dissection of complex traits. We envision that coupling cutting-edge technologies and the use of S. viridis for gene discovery will accelerate genetic research in millets in general. This will enable strategies and provide opportunities to increase productivity, especially in the semi-arid tropics of Asia and Africa where millets are staple food crops. PMID:27965689

  19. Microsatellite Variations of Elite Setaria Varieties Released during Last Six Decades in China.

    PubMed

    Jia, Guanqing; Liu, Xiaotong; Schnable, James C; Niu, Zhengang; Wang, Chunfang; Li, Yuhui; Wang, Shujun; Wang, Suying; Liu, Jinrong; Guo, Erhu; Zhi, Hui; Diao, Xianmin

    2015-01-01

    Crop improvement is a multifaceted micro-evolutionary process, involving changes in breeding approaches, planting configurations and consumption preferences of human beings. Recent research has started to identify the specific genes or genomic regions correlate to improved agronomic traits, however, an apparent blank between the genetic structure of crop elite varieties and their improving histories in diverse modern breeding programs is still in existence. Foxtail millet (Setaria italica) was one of the earliest cereal crops to be domesticated and served as a staple crop for early civilizations in China, where it is still widely grown today. In the present trial, a panel of foxtail millet elite varieties, which were released in the last sixty years in different geographical regions of China, was characterized using microsatellite markers (SSRs). A clear separation of two subpopulations corresponding to the two eco-geographical regions of foxtail millet production in China was identified by the dataset, which also indicated that in more recently released elite varieties, large quantities of accessions have been transferred from spring-sowing to summer-sowing ecotypes, likely as a result of breeding response to planting configurations. An association mapping study was conducted to identify loci controlling traits of major agronomic interest. Furthermore, selective sweeps involved in improvement of foxtail millet were identified as multi-diverse minor effect loci controlling different agronomic traits during the long-term improvement of elite varieties. Our results highlight the effect of transition of planting configuration and breeding preference on genetic evolvement of crop species.

  20. Parasitic Colitis

    PubMed Central

    Hechenbleikner, Elizabeth M.; McQuade, Jennifer A.

    2015-01-01

    Over one billion people worldwide harbor intestinal parasites. Parasitic intestinal infections have a predilection for developing countries due to overcrowding and poor sanitation but are also found in developed nations, such as the United States, particularly in immigrants or in the setting of sporadic outbreaks. Although the majority of people are asymptomatically colonized with parasites, the clinical presentation can range from mild abdominal discomfort or diarrhea to serious complications, such as perforation or bleeding. Protozoa and helminths (worms) are the two major classes of intestinal parasites. Protozoal intestinal infections include cryptosporidiosis, cystoisosporiasis, cyclosporiasis, balantidiasis, giardiasis, amebiasis, and Chagas disease, while helminth infections include ascariasis, trichuriasis, strongyloidiasis, enterobiasis, and schistosomiasis. Intestinal parasites are predominantly small intestine pathogens but the large intestine is also frequently involved. This article highlights important aspects of parasitic infections of the colon including epidemiology, transmission, symptoms, and diagnostic methods as well as appropriate medical and surgical treatment. PMID:26034403

  1. Parasitic Diseases

    MedlinePlus

    ... You can get them from contaminated food or water, a bug bite, or sexual contact. Some parasitic diseases are easily treated and some are not. Parasites range in size from tiny, ... Contaminated water supplies can lead to Giardia infections. Cats can ...

  2. Survival, activity and release of antigenic excretory secretory products and microfilariae of Setaria digitata maintained in artificial media.

    PubMed

    Sundar, S T B; D'Souza, Placid E

    2015-03-01

    The survival, activity and release of excretory secretory products from Setaria digitata, the filarial worm of cattle was studied. Adult female worms were maintained in vitro in DMEM and Tyrode solution. Worms incubated in DMEM were alive and very active for 2 days. The activity was moderate for another 2 days and after the fourth day increased mortality was observed. Antigenic excretory secretory products were also released. Worms incubated in Tyrode solution were very active without any mortality up to 4 h of incubation. Copious amount of ova and microfilaria were shed by the incubated worms in a time-dependent manner.

  3. Grain Yield and Quality of Foxtail Millet (Setaria italica L.) in Response to Tribenuron-Methyl

    PubMed Central

    Ning, Na; Yuan, Xiangyang; Dong, Shuqi; Wen, Yinyuan; Gao, Zhenpan; Guo, Meijun; Guo, Pingyi

    2015-01-01

    Foxtail millet (Setaria italica L.) is cultivated around the world for human and animal consumption. There is no suitable herbicide available for weed control in foxtail millet fields during the post-emergence stage. In this study, we investigated the effect and safety of the post-emergence herbicide tribenuron-methyl (TBM) on foxtail millet in terms of grain yield and quality using a split-plot field design. Field experiments were conducted using two varieties in 2013 and 2014, i.e., high-yielding hybrid Zhangzagu 10 and high-quality conventional Jingu 21. TBM treatments at 11.25 to 90 g ai ha−1 reduced root and shoot biomass and grain yield to varying degrees. In each of the two years, grain yield declined by 50.2% in Zhangzagu 10 with a herbicide dosage of 45 g ai ha−1 and by 45.2% in Jingu 21 with a herbicide dosage of 22.5 g ai ha−1 (recommended dosage). Yield reduction was due to lower grains per panicle, 1000-grain weight, panicle length, and panicle diameter. Grain yield was positively correlated with grains per panicle and 1000-grain weight, but not with panicles ha−1. With respect to grain protein content at 22.5 g ai ha−1, Zhangzagu 10 was similar to the control, whereas Jingu 21 was markedly lower. An increase in TBM dosage led to a decrease in grain Mn, Cu, Fe, and Zn concentrations. In conclusion, the recommended dosage of TBM was relatively safe for Zhangzagu 10, but not for Jingu 21. Additionally, the hybrid variety Zhangzagu 10 had a greater tolerance to TBM than the conventional variety Jingu 21. PMID:26565992

  4. Methods for Performing Crosses in Setaria viridis, a New Model System for the Grasses

    PubMed Central

    Jiang, Hui; Barbier, Hugues; Brutnell, Thomas

    2013-01-01

    Setaria viridis is an emerging model system for C4 grasses. It is closely related to the bioenergy feed stock switchgrass and the grain crop foxtail millet. Recently, the 510 Mb genome of foxtail millet, S. italica, has been sequenced 1,2 and a 25x coverage genome sequence of the weedy relative S. viridis is in progress. S. viridis has a number of characteristics that make it a potentially excellent model genetic system including a rapid generation time, small stature, simple growth requirements, prolific seed production 3 and developed systems for both transient and stable transformation 4. However, the genetics of S. viridis is largely unexplored, in part, due to the lack of detailed methods for performing crosses. To date, no standard protocol has been adopted that will permit rapid production of seeds from controlled crosses. The protocol presented here is optimized for performing genetic crosses in S. viridis, accession A10.1. We have employed a simple heat treatment with warm water for emasculation after pruning the panicle to retain 20-30 florets and labeling of flowers to eliminate seeds resulting from newly developed flowers after emasculation. After testing a series of heat treatments at permissive temperatures and varying the duration of dipping, we have established an optimum temperature and time range of 48 °C for 3-6 min. By using this method, a minimum of 15 crosses can be performed by a single worker per day and an average of 3-5 outcross progeny per panicle can be recovered. Therefore, an average of 45-75 outcross progeny can be produced by one person in a single day. Broad implementation of this technique will facilitate the development of recombinant inbred line populations of S. viridis X S. viridis or S. viridis X S. italica, mapping mutations through bulk segregant analysis and creating higher order mutants for genetic analysis. PMID:24121645

  5. Geographic variation in the flood-induced fluctuating temperature requirement for germination in Setaria parviflora seeds.

    PubMed

    Mollard, F P O; Insausti, P

    2011-07-01

    Our aim was to search for specific seed germinative strategies related to flooding escape in Setaria parviflora, a common species across the Americas. For this purpose, we investigated induction after floods, in relation to fluctuating temperature requirements for germination in seeds from mountain, floodplain and successional grasslands. A laboratory experiment was conducted in which seeds were imbibed or immersed in water at 5°C. Seeds were also buried in flood-prone and upland grasslands and exhumed during the flooding season. Additionally, seeds were buried in flooded or drained grassland mesocosms. Germination of exhumed seeds was assayed at 25°C or at 20°C/30°C in the dark or in the presence of red light pulses. After submergence or soil flooding, a high fraction (>32%) of seeds from the floodplain required fluctuating temperatures to germinate. In contrast, seeds from the mountains showed maximum differences in germination between fluctuating and constant temperature treatment only after imbibition (35%) or in non-flooded soil conditions (40%). The fluctuating temperature requirement was not clearly related to the foregoing conditions in the successional grassland seeds. Maximum germination could also be attained with red light pulses to seeds from mountain and successional grasslands. Results show that the fluctuating temperature requirement might help floodplain seeds to germinate after floods, indicating a unique feature of the dormancy of S. parviflora seeds from floodplains, which suggests an adaptive advantage aimed at postponing emergence during inundation periods. In contrast, the fluctuating temperature required for germination among seeds from mountain and successional grasslands show its importance for gap detection.

  6. Roles of Aquaporins in Setaria viridis Stem Development and Sugar Storage

    PubMed Central

    McGaughey, Samantha A.; Osborn, Hannah L.; Chen, Lily; Pegler, Joseph L.; Tyerman, Stephen D.; Furbank, Robert T.; Byrt, Caitlin S.; Grof, Christopher P. L.

    2016-01-01

    Setaria viridis is a C4 grass used as a model for bioenergy feedstocks. The elongating internodes in developing S. viridis stems grow from an intercalary meristem at the base, and progress acropetally toward fully expanded cells that store sugar. During stem development and maturation, water flow is a driver of cell expansion and sugar delivery. As aquaporin proteins are implicated in regulating water flow, we analyzed elongating and mature internode transcriptomes to identify putative aquaporin encoding genes that had particularly high transcript levels during the distinct stages of internode cell expansion and maturation. We observed that SvPIP2;1 was highly expressed in internode regions undergoing cell expansion, and SvNIP2;2 was highly expressed in mature sugar accumulating regions. Gene co-expression analysis revealed SvNIP2;2 expression was highly correlated with the expression of five putative sugar transporters expressed in the S. viridis internode. To explore the function of the proteins encoded by SvPIP2;1 and SvNIP2;2, we expressed them in Xenopus laevis oocytes and tested their permeability to water. SvPIP2;1 and SvNIP2;2 functioned as water channels in X. laevis oocytes and their permeability was gated by pH. Our results indicate that SvPIP2;1 may function as a water channel in developing stems undergoing cell expansion and SvNIP2;2 is a candidate for retrieving water and possibly a yet to be determined solute from mature internodes. Future research will investigate whether changing the function of these proteins influences stem growth and sugar yield in S. viridis. PMID:28018372

  7. Molecular diversity and population structure of Chinese green foxtail [Setaria viridis (L.) Beauv.] revealed by microsatellite analysis.

    PubMed

    Jia, Guanqing; Shi, Shenkui; Wang, Chunfang; Niu, Zhengang; Chai, Yang; Zhi, Hui; Diao, Xianmin

    2013-09-01

    Green foxtail (Setaria viridis) is a new model plant for the genomic investigation of C4 photosynthesis biology. As the ancestor of foxtail millet (Setaria italica), an ancient cereal of great importance in arid regions of the world, green foxtail is crucial for the study of domestication and evolution of this ancient crop. In the present study, 288 green foxtail accessions, which were collected from all geographical regions of China, were analysed using 77 simple sequence repeats (SSRs) that cover the whole genome. A high degree of molecular diversity was detected in these accessions, with an average of 33.5 alleles per locus. Two clusters, which were inconsistent with the distribution of eco-geographical regions in China, were inferred from STRUCTURE, Neighbor-Joining, and principal component analysis, indicating a partially mixed distribution of Chinese green foxtails. The higher subpopulation diversity was from accessions mainly collected from North China. A low level of linkage disequilibrium was observed in the green foxtail genome. Furthermore, a combined analysis of green foxtail and foxtail millet landraces was conducted, and the origin and domestication of foxtail millet was inferred in North China.

  8. Foodborne Parasites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foodborne infections are a significant cause of morbidity and mortality worldwide, and foodborne parasitic diseases, though not as widespread as bacterial and viral infections, are common on all continents and in most ecosystems, including arctic, temperate, and tropical regions. Certain foodborne ...

  9. Parasitic Apologies

    ERIC Educational Resources Information Center

    Galatolo, Renata; Ursi, Biagio; Bongelli, Ramona

    2016-01-01

    The action of apologizing can be accomplished as the main business of the interaction or incidentally while participants are doing something else. We refer to these apologies as "parasitic apologies," because they are produced "en passant" (Schegloff, 2007), and focus our analysis on this type of apology occurring at the…

  10. Prevalence of non-strongyle gastrointestinal parasites of horses in Riyadh region of Saudi Arabia

    PubMed Central

    AL Anazi, Abdullah D.; Alyousif, Mohamed S.

    2011-01-01

    This study aimed to provide recent data on the occurrence of non-strongyle intestinal parasite infestation in horses in the Riyadh region of Saudi Arabia as a basis for developing parasite control strategies. We conducted necropsy for 45 horses from September 2006 to November 2007 in the Riyadh region, Saudi Arabia. 39 out of 45 horses were infected with intestinal parasites with an infestation rate of 86.6%. Infestations with seven nematode species and two species of Gasterophilus larva were found. The most prevalent parasites were Strongyloides westeri (64.4%) and Parascaris equorum (28.8%) followed by Habronema muscae (22.2%). Trichostrongylus axei and Oxyuris equi were less common at (11.1%) and (8.8%), respectively. Habronema megastoma and Setaria equine were found in two horses only (4.4%). Gasterophilus intestinalis larvae were recovered from 39 horses (86.6%) and Gasterophilus nasalis larvae were found in 17 horses (37.7%). Season had a significant effect on the prevalence of P. equorum and G. nasalis, while age of horses had a significant effect only on the prevalence of P. equorum. The husbandry in Saudi Arabia appears to be conductive to parasites transmitted in stables or by insects rather than in pasture. PMID:23961139

  11. Prevalence of non-strongyle gastrointestinal parasites of horses in Riyadh region of Saudi Arabia.

    PubMed

    Al Anazi, Abdullah D; Alyousif, Mohamed S

    2011-07-01

    This study aimed to provide recent data on the occurrence of non-strongyle intestinal parasite infestation in horses in the Riyadh region of Saudi Arabia as a basis for developing parasite control strategies. We conducted necropsy for 45 horses from September 2006 to November 2007 in the Riyadh region, Saudi Arabia. 39 out of 45 horses were infected with intestinal parasites with an infestation rate of 86.6%. Infestations with seven nematode species and two species of Gasterophilus larva were found. The most prevalent parasites were Strongyloides westeri (64.4%) and Parascaris equorum (28.8%) followed by Habronema muscae (22.2%). Trichostrongylus axei and Oxyuris equi were less common at (11.1%) and (8.8%), respectively. Habronema megastoma and Setaria equine were found in two horses only (4.4%). Gasterophilus intestinalis larvae were recovered from 39 horses (86.6%) and Gasterophilus nasalis larvae were found in 17 horses (37.7%). Season had a significant effect on the prevalence of P. equorum and G. nasalis, while age of horses had a significant effect only on the prevalence of P. equorum. The husbandry in Saudi Arabia appears to be conductive to parasites transmitted in stables or by insects rather than in pasture.

  12. Low-level parasitic worm burdens may reduce body condition in free-ranging red deer (Cervus elaphus).

    PubMed

    Irvine, R J; Corbishley, H; Pilkington, J G; Albon, S D

    2006-10-01

    Regulation of ungulate populations by parasites relies on establishing a density-dependent relationship between infection and vital demographic rates which may act through the effect of parasites on body condition. We examine evidence for parasite impacts in 285 red deer (Cervus elaphus) harvested during 1991 and 1992 on the Isle of Rum. In the abomasa, prevalence of nematodes was 100% and the most abundant genus observed were Ostertagia species, however, mean intensity of infection was low (less than 1000) relative to other studies. Additional species, also present in low numbers, included Nematodirus spp., Capillaria spp., Cooperia spp., Monieza expanza, Oesophagostomum venulosum and Trichuris ovis. Lungworm (Dictyocaulus spp.) and tissue worm (Elaphostronygylus cervi) larvae were also observed in faecal samples. There was no evidence for acquired immunity to abomasal nematodes. Despite low levels of infection, both adult male and female deer showed significant negative correlation between indices of condition (kidney fat index, dressed carcass weight and larder weight) and intensity of Ostertagia spp. infection. However, there was no evidence that pregnancy rate in females was related to intensity of infection. For calves, there was no relationship between body condition and intensity of infection. The apparent subclinical effects of low-level parasite infection on red deer performance could alternatively be due to animals in poorer nutritional state being more susceptible to infection. Either way the results suggest that further studies of wild populations are justified, in particular where high local host densities exist or alternative ungulate hosts are present, and, where experimental treatments are tractable.

  13. Temperature Responses of C4 Photosynthesis: Biochemical Analysis of Rubisco, Phosphoenolpyruvate Carboxylase, and Carbonic Anhydrase in Setaria viridis1[OPEN

    PubMed Central

    Boyd, Ryan A.; Gandin, Anthony; Cousins, Asaph B.

    2015-01-01

    The photosynthetic assimilation of CO2 in C4 plants is potentially limited by the enzymatic rates of Rubisco, phosphoenolpyruvate carboxylase (PEPc), and carbonic anhydrase (CA). Therefore, the activity and kinetic properties of these enzymes are needed to accurately parameterize C4 biochemical models of leaf CO2 exchange in response to changes in CO2 availability and temperature. There are currently no published temperature responses of both Rubisco carboxylation and oxygenation kinetics from a C4 plant, nor are there known measurements of the temperature dependency of the PEPc Michaelis-Menten constant for its substrate HCO3−, and there is little information on the temperature response of plant CA activity. Here, we used membrane inlet mass spectrometry to measure the temperature responses of Rubisco carboxylation and oxygenation kinetics, PEPc carboxylation kinetics, and the activity and first-order rate constant for the CA hydration reaction from 10°C to 40°C using crude leaf extracts from the C4 plant Setaria viridis. The temperature dependencies of Rubisco, PEPc, and CA kinetic parameters are provided. These findings describe a new method for the investigation of PEPc kinetics, suggest an HCO3− limitation imposed by CA, and show similarities between the Rubisco temperature responses of previously measured C3 species and the C4 plant S. viridis. PMID:26373659

  14. The solute specificity profiles of nucleobase cation symporter 1 (NCS1) from Zea mays and Setaria viridis illustrate functional flexibility.

    PubMed

    Rapp, Micah; Schein, Jessica; Hunt, Kevin A; Nalam, Vamsi; Mourad, George S; Schultes, Neil P

    2016-03-01

    The solute specificity profiles (transport and binding) for the nucleobase cation symporter 1 (NCS1) proteins, from the closely related C4 grasses Zea mays and Setaria viridis, differ from that of Arabidopsis thaliana and Chlamydomonas reinhardtii NCS1. Solute specificity profiles for NCS1 from Z. mays (ZmNCS1) and S. viridis (SvNCS1) were determined through heterologous complementation studies in NCS1-deficient Saccharomyces cerevisiae strains. The four Viridiplantae NCS1 proteins transport the purines adenine and guanine, but unlike the dicot and algal NCS1, grass NCS1 proteins fail to transport the pyrimidine uracil. Despite the high level of amino acid sequence similarity, ZmNCS1 and SvNCS1 display distinct solute transport and recognition profiles. SvNCS1 transports adenine, guanine, hypoxanthine, cytosine, and allantoin and competitively binds xanthine and uric acid. ZmNCS1 transports adenine, guanine, and cytosine and competitively binds, 5-fluorocytosine, hypoxanthine, xanthine, and uric acid. The differences in grass NCS1 profiles are due to a limited number of amino acid alterations. These amino acid residues do not correspond to amino acids essential for overall solute and cation binding or solute transport, as previously identified in bacterial and fungal NCS1, but rather may represent residues involved in subtle solute discrimination. The data presented here reveal that within Viridiplantae, NCS1 proteins transport a broad range of nucleobase compounds and that the solute specificity profile varies with species.

  15. TRANSPARENT TESTA GLABRA 1 ubiquitously regulates plant growth and development from Arabidopsis to foxtail millet (Setaria italica).

    PubMed

    Liu, Kaige; Qi, Shuanghui; Li, Dong; Jin, Changyu; Gao, Chenhao; Duan, Shaowei; Feng, Baili; Chen, Mingxun

    2017-01-01

    TRANSPARENT TESTA GLABRA 1 of Arabidopsis thaliana (AtTTG1) is a WD40 repeat transcription factor that plays multiple roles in plant growth and development, particularly in seed metabolite production. In the present study, to determine whether SiTTG1 of the phylogenetically distant monocot foxtail millet (Setaria italica) has similar functions, we used transgenic Arabidopsis and Nicotiana systems to explore its activities. We found that SiTTG1 functions as a transcription factor. Overexpression of the SiTTG1 gene rescued many of the mutant phenotypes in Arabidopsis ttg1-13 plants. Additionally, SiTTG1 overexpression fully corrected the reduced expression of mucilage biosynthetic genes, and the induced expression of genes involved in accumulation of seed fatty acids and storage proteins in developing seeds of ttg1-13 plants. Ectopic expression of SiTTG1 restored the sensitivity of the ttg1-13 mutant to salinity and high glucose stresses during germination and seedling establishment, and restored altered expression levels of some stress-responsive genes in ttg1-13 seedlings to the wild type level under salinity and glucose stresses. Our results provide information that will be valuable for understanding the function of TTG1 from monocot to dicot species and identifying a promising target for genetic manipulation of foxtail millet to improve the amount of seed metabolites.

  16. Effects of reduced carbonic anhydrase activity on CO2 assimilation rates in Setaria viridis: a transgenic analysis.

    PubMed

    Osborn, Hannah L; Alonso-Cantabrana, Hugo; Sharwood, Robert E; Covshoff, Sarah; Evans, John R; Furbank, Robert T; von Caemmerer, Susanne

    2017-01-01

    In C4 species, the major β-carbonic anhydrase (β-CA) localized in the mesophyll cytosol catalyses the hydration of CO2 to HCO3(-), which phosphoenolpyruvate carboxylase uses in the first step of C4 photosynthesis. To address the role of CA in C4 photosynthesis, we generated transgenic Setaria viridis depleted in β-CA. Independent lines were identified with as little as 13% of wild-type CA. No photosynthetic defect was observed in the transformed lines at ambient CO2 partial pressure (pCO2). At low pCO2, a strong correlation between CO2 assimilation rates and CA hydration rates was observed. C(18)O(16)O isotope discrimination was used to estimate the mesophyll conductance to CO2 diffusion from the intercellular air space to the mesophyll cytosol (gm) in control plants, which allowed us to calculate CA activities in the mesophyll cytosol (Cm). This revealed a strong relationship between the initial slope of the response of the CO2 assimilation rate to cytosolic pCO2 (ACm) and cytosolic CA activity. However, the relationship between the initial slope of the response of CO2 assimilation to intercellular pCO2 (ACi) and cytosolic CA activity was curvilinear. This indicated that in S. viridis, mesophyll conductance may be a contributing limiting factor alongside CA activity to CO2 assimilation rates at low pCO2.

  17. Tolerance to high soil temperature in foxtail millet (Setaria italica L.) is related to shoot and root growth and metabolism.

    PubMed

    Aidoo, Moses Kwame; Bdolach, Eyal; Fait, Aaron; Lazarovitch, Naftali; Rachmilevitch, Shimon

    2016-09-01

    Roots play important roles in regulating whole-plant carbon and water relations in response to extreme soil temperature. Three foxtail millet (Setaria italica L.) lines (448-Ames 21521, 463-P1391643 and 523-P1219619) were subjected to two different soil temperatures (28 and 38 °C). The gas exchange, chlorophyll fluorescence, root morphology and central metabolism of leaves and roots were studied at the grain-filling stage. High soil temperature (38 °C) significantly influenced the shoot transpiration, stomatal conductance, photosynthesis, root growth and metabolism of all lines. The root length and area were significantly reduced in lines 448 and 463 in response to the stress, while only a small non-specific reduction was observed in line 523 in response to the treatment. The shift of root metabolites in response to high soil temperature was also genotype specific. In response to high soil temperature, glutamate, proline and pyroglutamate were reduced in line 448, and alanine, aspartate, glycine, pyroglutamate, serine, threonine and valine were accumulated in line 463. In the roots of line 523, serine, threonine, valine, isomaltose, maltose, raffinose, malate and itaconate were accumulated. Root tolerance to high soil temperature was evident in line 523, in its roots growth potential, lower photosynthesis and stomatal conductance rates, and effective utilization and assimilation of membrane carbon and nitrogen, coupled with the accumulation of protective metabolites.

  18. Assembling the Setaria italica L. Beauv. genome into nine chromosomes and insights into regions affecting growth and drought tolerance

    PubMed Central

    Tsai, Kevin J.; Lu, Mei-Yeh Jade; Yang, Kai-Jung; Li, Mengyun; Teng, Yuchuan; Chen, Shihmay; Ku, Maurice S. B.; Li, Wen-Hsiung

    2016-01-01

    The diploid C4 plant foxtail millet (Setaria italica L. Beauv.) is an important crop in many parts of Africa and Asia for the vast consumption of its grain and ability to grow in harsh environments, but remains understudied in terms of complete genomic architecture. To date, there have been only two genome assembly and annotation efforts with neither assembly reaching over 86% of the estimated genome size. We have combined de novo assembly with custom reference-guided improvements on a popular cultivar of foxtail millet and have achieved a genome assembly of 477 Mbp in length, which represents over 97% of the estimated 490 Mbp. The assembly anchors over 98% of the predicted genes to the nine assembled nuclear chromosomes and contains more functional annotation gene models than previous assemblies. Our annotation has identified a large number of unique gene ontology terms related to metabolic activities, a region of chromosome 9 with several growth factor proteins, and regions syntenic with pearl millet or maize genomic regions that have been previously shown to affect growth. The new assembly and annotation for this important species can be used for detailed investigation and future innovations in growth for millet and other grains. PMID:27734962

  19. Protozoan Parasites.

    PubMed

    Custodio, Haidee

    2016-02-01

    • Stool antigen detection for Cryptosporidium sp, Giardia lamblia and Entamoeba histolytica are now commercially available, have better sensitivity and specificity than the traditional stool microscopy, and are less dependent on personnel skill. Tests employing newer techniques with faster turnaround time are also available for diagnosing trichomoniasis.• Nitazoxanide, the only U.S. Food and Drug Administration-approved medication for therapy of cryptosporidiosis, is effective among immunocompetent patients. However, on the basis of strong evidence from multiple clinical trials, nitazoxanide is considered ineffective among immunocompromised patients. (14) • Giardiasis can be asymptomatic or have a chronic course leading to malabsorption and failure to thrive. It can be treated with metronidazole, tinidazole, or nitazoxanide. On the basis of growing observational studies, postinfectious and extraintestinal manifestations of giardiasis occur, but the mechanisms are unclear. Given the high prevalence of giardiasis, public health implications need to be defined. (16) • Eradicating E histolytica from the gastrointestinal tract requires only intraluminal agent therapy. Therapy for invasive illnesses requires use of imidazole followed by intraluminal agents to eliminate persistent intraluminal parasites. • Malaria is considered the most lethal parasitic infection, with Plasmodium falciparum as the predominant cause of mortality. P vivax and P ovale can be dormant in the liver, and primaquine is necessary to resolve infection by P vivax and P ovale. • Among immunocompetent patients, infection with Toxoplasma gondii may be asymptomatic, involve localized lymphadenopathy, or cause ocular infection. In immunocompromised patients, reactivation or severe infection is not uncommon. On the basis of limited observational studies (there are no well-controlled randomized trials), therapy is recommended for acute infection during pregnancy to prevent transmission to the

  20. Gene mapping and functional analysis of the novel leaf color gene SiYGL1 in foxtail millet [Setaria italica (L.) P. Beauv].

    PubMed

    Li, Wen; Tang, Sha; Zhang, Shuo; Shan, Jianguo; Tang, Chanjuan; Chen, Qiannan; Jia, Guanqing; Han, Yuanhuai; Zhi, Hui; Diao, Xianmin

    2016-05-01

    Setaria italica and its wild ancestor Setaria viridis are emerging as model systems for genetics and functional genomics research. However, few systematic gene mapping or functional analyses have been reported in these promising C4 models. We herein isolated the yellow-green leaf mutant (siygl1) in S. italica using forward genetics approaches. Map-based cloning revealed that SiYGL1, which is a recessive nuclear gene encoding a magnesium-chelatase D subunit (CHLD), is responsible for the mutant phenotype. A single Phe to Leu amino acid change occurring near the ATPase-conserved domain resulted in decreased chlorophyll (Chl) accumulation and modified chloroplast ultrastructure. However, the mutation enhanced the light-use efficiency of the siygl1 mutant, suggesting that the mutated CHLD protein does not completely lose its original activity, but instead, gains novel features. A transcriptional analysis of Chl a oxygenase revealed that there is a strong negative feedback control of Chl b biosynthesis in S. italica. The SiYGL1 mRNA was expressed in all examined tissues, with higher expression observed in the leaves. Comparison of gene expression profiles in wild-type and siygl1 mutant plants indicated that SiYGL1 regulates a subset of genes involved in photosynthesis (rbcL and LHCB1), thylakoid development (DEG2) and chloroplast signaling (SRP54CP). These results provide information regarding the mutant phenotype at the transcriptional level. This study demonstrated that the genetic material of a Setaria species could be ideal for gene discovery investigations using forward genetics approaches and may help to explain the molecular mechanisms associated with leaf color variation.

  1. Single-dose Intramuscular-injection Toxicology Test of Water-soluble Carthami-flos and Cervi cornu parvum Pharmacopuncture in a Rat Model

    PubMed Central

    Park, Sunju; Sun, Seung-Ho

    2015-01-01

    Objectives: The aim of the study is to investigate both the single-dose intramuscular injection toxicity and the approximate lethal dose of water-soluble Carthami-flos and Cervi cornu parvum pharmacopuncture (WCFC) in male and female Sprague-Dawley (SD) rats. Methods: The study was conducted at Biotoxtech Co. according to the Good Laboratory Practice (GLP) regulation and the toxicity test guidelines of the Ministry of Food and Drug Safety (MFDS) after approval of the Institutional Animal Care and Use Committee. Dosages for the control, high dose, middle dose and low dose groups were 0.5 mL/animal of saline and 0.5, 0.25 and 0.125 mL/animal of WCFC, respectively. WCFC was injected into the muscle of the left femoral region by using a disposable syringe (1 mL, 26 gauge). The general symptoms and mortality were observed 30 minutes, 1, 2, 4, and 6 hours after the first injection and then daily for 14 days after the injection. The body weights of the SD rats were measured on the day of the injection (before injection) and on the third, seventh, and fourteenth days after the injection. Serum biochemical and hematologic tests, necropsy examinations, and histopathologic examinations at the injection site were performed after the observation period. Results: No deaths, abnormal clinical symptoms, or significant weight changes were observed in either male or female SD rats in the control or the test (0.125, 0.25, and 0.5 mL/animal) groups during the observation period. No significant differences in hematology and serum biochemistry and no macroscopic abnormalities at necropsy were found. No abnormal reactions at injection sites were noted on the topical tolerance tests. Conclusion: The results of this single-dose toxicity study show that WCFC is safe, its lethal doses in male and female SD rats being estimated to be higher than 0.5 mL/animal. PMID:26392912

  2. Global analysis of WRKY transcription factor superfamily in Setaria identifies potential candidates involved in abiotic stress signaling

    PubMed Central

    Muthamilarasan, Mehanathan; Bonthala, Venkata S.; Khandelwal, Rohit; Jaishankar, Jananee; Shweta, Shweta; Nawaz, Kashif; Prasad, Manoj

    2015-01-01

    Transcription factors (TFs) are major players in stress signaling and constitute an integral part of signaling networks. Among the major TFs, WRKY proteins play pivotal roles in regulation of transcriptional reprogramming associated with stress responses. In view of this, genome- and transcriptome-wide identification of WRKY TF family was performed in the C4model plants, Setaria italica (SiWRKY) and S. viridis (SvWRKY), respectively. The study identified 105 SiWRKY and 44 SvWRKY proteins that were computationally analyzed for their physicochemical properties. Sequence alignment and phylogenetic analysis classified these proteins into three major groups, namely I, II, and III with majority of WRKY proteins belonging to group II (53 SiWRKY and 23 SvWRKY), followed by group III (39 SiWRKY and 11 SvWRKY) and group I (10 SiWRKY and 6 SvWRKY). Group II proteins were further classified into 5 subgroups (IIa to IIe) based on their phylogeny. Domain analysis showed the presence of WRKY motif and zinc finger-like structures in these proteins along with additional domains in a few proteins. All SiWRKY genes were physically mapped on the S. italica genome and their duplication analysis revealed that 10 and 8 gene pairs underwent tandem and segmental duplications, respectively. Comparative mapping of SiWRKY and SvWRKY genes in related C4 panicoid genomes demonstrated the orthologous relationships between these genomes. In silico expression analysis of SiWRKY and SvWRKY genes showed their differential expression patterns in different tissues and stress conditions. Expression profiling of candidate SiWRKY genes in response to stress (dehydration and salinity) and hormone treatments (abscisic acid, salicylic acid, and methyl jasmonate) suggested the putative involvement of SiWRKY066 and SiWRKY082 in stress and hormone signaling. These genes could be potential candidates for further characterization to delineate their functional roles in abiotic stress signaling. PMID:26635818

  3. SiASR4, the Target Gene of SiARDP from Setaria italica, Improves Abiotic Stress Adaption in Plants

    PubMed Central

    Li, Jianrui; Dong, Yang; Li, Cong; Pan, Yanlin; Yu, Jingjuan

    2017-01-01

    Drought and other types of abiotic stresses negatively affect plant growth and crop yields. The abscisic acid-, stress-, and ripening-induced (ASR) proteins play important roles in the protection of plants against abiotic stress. However, the regulatory pathway of the gene encoding this protein remains to be elucidated. In this study, the foxtail millet (Setaria italica) ASR gene, SiASR4, was cloned and characterized. SiASR4 localized to the cell nucleus, cytoplasm and cytomembrane, and the protein contained 102 amino acids, including an ABA/WDS (abscisic acid/water-deficit stress) domain, with a molecular mass of 11.5 kDa. The abundance of SiASR4 transcripts increased after treatment with ABA, NaCl, and PEG in foxtail millet seedlings. It has been reported that the S. italica ABA-responsive DRE-binding protein (SiARDP) binds to a DNA sequence with a CCGAC core and that there are five dehydration-responsive element (DRE) motifs within the SiASR4 promoter. Our analyses demonstrated that the SiARDP protein could bind to the SiASR4 promoter in vitro and in vivo. The expression of SiASR4 increased in SiARDP-overexpressing plants. SiASR4-transgenic Arabidopsis and SiASR4-overexpressing foxtail millet exhibited enhanced tolerance to drought and salt stress. Furthermore, the transcription of stress-responsive and reactive oxygen species (ROS) scavenger-associated genes was activated in SiASR4 transgenic plants. Together, these findings show that SiASR4 functions in the adaption to drought and salt stress and is regulated by SiARDP via an ABA-dependent pathway. PMID:28127300

  4. Equine immunity to parasites.

    PubMed

    Klei, T R

    2000-04-01

    Helminths are among the most significant parasites of horses in developed countries. This article examines immune responses against helminth parasites and the implications that immunologic investigations have on vaccine development, improvement of diagnostic procedures, and disease eradication.

  5. Intestinal parasitic infection.

    PubMed

    Park, Mi-Suk; Kim, Ki Whang; Ha, Hyun Kwon; Lee, Dong Ho

    2008-01-01

    In general, gastrointestinal tract is the primary involvement site of parasites during their life cycle. In this article, we will describe amebiasis, ascariasis, and anisakiasis among the many common intestinal parasitic diseases. We will review the epidemiology, life cycles, clinical manifestations and complications, and illustrate detailed imaging findings of intestinal parasites. Recognizing features of parasitic infection is important to establish an early diagnosis that leads to prompt treatment and helps avoid unnecessary surgery.

  6. A Non-specific Setaria italica Lipid Transfer Protein Gene Plays a Critical Role under Abiotic Stress

    PubMed Central

    Pan, Yanlin; Li, Jianrui; Jiao, Licong; Li, Cong; Zhu, Dengyun; Yu, Jingjuan

    2016-01-01

    Lipid transfer proteins (LTPs) are a class of cysteine-rich soluble proteins having small molecular weights. LTPs participate in flower and seed development, cuticular wax deposition, also play important roles in pathogen and abiotic stress responses. A non-specific LTP gene (SiLTP) was isolated from a foxtail millet (Setaria italica) suppression subtractive hybridization library enriched for differentially expressed genes after abiotic stress treatments. A semi-quantitative reverse transcriptase PCR analysis showed that SiLTP was expressed in all foxtail millet tissues. Additionally, the SiLTP promoter drove GUS expression in root tips, stems, leaves, flowers, and siliques of transgenic Arabidopsis. Quantitative real-time PCR indicated that the SiLTP expression was induced by NaCl, polyethylene glycol, and abscisic acid (ABA). SiLTP was localized in the cytoplasm of tobacco leaf epidermal cells and maize protoplasts. The ectopic expression of SiLTP in tobacco resulted in higher levels of salt and drought tolerance than in the wild type (WT). To further assess the function of SiLTP, SiLTP overexpression (OE) and RNA interference (RNAi)-based transgenic foxtail millet were obtained. SiLTP-OE lines performed better under salt and drought stresses compared with WT plants. In contrast, the RNAi lines were much more sensitive to salt and drought compared than WT. Electrophoretic mobility shift assays and yeast one-hybrids indicated that the transcription factor ABA-responsive DRE-binding protein (SiARDP) could bind to the dehydration-responsive element of SiLTP promoter in vitro and in vivo, respectively. Moreover, the SiLTP expression levels were higher in SiARDP-OE plants compared than the WT. These results confirmed that SiLTP plays important roles in improving salt and drought stress tolerance of foxtail millet, and may partly be upregulated by SiARDP. SiLTP may provide an effective genetic resource for molecular breeding in crops to enhance salt and drought

  7. Increasing Selenium and Yellow Pigment Concentrations in Foxtail Millet (Setaria italica L.) Grain with Foliar Application of Selenite.

    PubMed

    Ning, Na; Yuan, Xiang-Yang; Dong, Shu-Qi; Wen, Yin-Yuan; Gao, Zhen-Pan; Guo, Mei-Jun; Guo, Ping-Yi

    2016-03-01

    Although addition of selenium (Se) is known to increase Se in crops, it is unclear whether exogenous Se is linked to nutritional and functional components in foxtail millet (Setaria italica L.). In this study, we examined the potential of increasing Se and yellow pigment (YP) in foxtail millet grain by foliar application of Se. Field experiments were conducted during the growing season of foxtail millet in 2013 and 2014 to assess the effects of foliar spray of sodium selenite (10-210 g Se ha(-1)) on the yield, Se uptake and accumulation, total YP, and microminerals in the grain. Average grain yields with Se application were 5.60 and 4.53 t ha(-1) in the 2 years, showing no significant differences from the unfertilized control. However, grain Se concentration increased linearly with Se application rate, by 8.92 and 6.09 μg kg(-1) in the 2 years with application of 1 g Se ha(-1) (maximum grain recovery rates of Se fertilizer, 52 and 28 %). Likewise, total grain YP concentration markedly increased by 0.038 and 0.031 mg kg(-1) in the 2 years with application of 1 g Se ha(-1). Grain Mn, Cu, Fe, and Zn concentrations were not significantly affected by Se application. This study indicated that foliar application of Se effectively and reliably increased the concentrations of Se and YP in foxtail millet grain without affecting the yield or mineral micronutrient concentrations. Thus, foliar-applied selenite has a significant potential to increase the concentrations of selenium and YP (putative lutein (Shen, J Cereal Sci 61:86-93, 2015; Abdel-Aal, Cereal Chem 79:455-457, 2002; Abdel-Aal, J Agric Food Chem 55:787-794, 2007)) of foxtail millet and, thus, the health benefits of this crop.

  8. Parasites, Plants, and People.

    PubMed

    Johnson, Marion; Moore, Tony

    2016-06-01

    Anthelminthic resistance is acknowledged worldwide and is a major problem in Aotearoa New Zealand, thus alternative parasite management strategies are imperative. One Health is an initiative linking animal, human, and environmental health. Parasites, plants, and people illustrate the possibilities of providing diverse diets for stock thereby lowering parasite burdens, improving the cultural wellbeing of a local community, and protecting the environment.

  9. Antifilarial effect of ursolic acid from Nyctanthes arbortristis: molecular and biochemical evidences.

    PubMed

    Saini, Prasanta; Gayen, Prajna; Kumar, Deepak; Nayak, Ananya; Mukherjee, Niladri; Mukherjee, Suprabhat; Pal, Bikas C; Babu, Santi P Sinha

    2014-10-01

    A bio-assay guided fractionation and purification approach was used to examine in vitro antifilarial activities of the crude methanolic extract of Nyctanthes arbortristis as well as fractions and isolated compound. From ethyl-acetate fraction we isolated and identified a triterpenoid compound which has been characterized as ursolic acid (UA) by HPLC and NMR data. We are reporting for the first time isolation and identification of UA from the leaves of N. arbortristis. The crude extract and UA showed significant micro- as well as macrofilaricidal activities against the oocyte, microfilaria and adult of Setaria cervi (S. cervi) by dye exclusion test and MTT reduction assay. Significant microfilaricidal activity of UA was further proved against mf of W. bancrofti by viability assay. The findings thus provide a new lead for development of a suitable filaricide from natural products. The molecular mechanism of UA was investigated by performing TUNEL, Hoechst staining, Annexin V-Cy3, flow cytometric analysis and DNA fragmentation assay. Differential expressions of pro- and anti-apoptotic genes were observed at the transcription and translational levels in a dose-dependent manner. Depletion in the worm GSH level and elevation in the parasite GST, SOD and super oxide anion indicated the generation of ROS. In this investigation we are reporting for the first time that UA acts its antifilarial effect through induction of apoptosis and by downregulating and altering the level of some key antioxidants like GSH, GST and SOD of S. cervi.

  10. Parasites and supernormal manipulation.

    PubMed Central

    Holen, Ø. H.; Saetre, G. P.; Slagsvold, T.; Stenseth, N. C.

    2001-01-01

    Social parasites may exploit their hosts by mimicking other organisms that the hosts normally benefit from investing in or responding to in some other way. Some parasites exaggerate key characters of the organisms they mimic, possibly in order to increase the response from the hosts. The huge gape and extreme begging intensity of the parasitic common cuckoo chick (Cuculus canorus) may be an example. In this paper, the evolutionary stability of manipulating hosts through exaggerated signals is analysed using game theory. Our model indicates that a parasite's signal intensity must be below a certain threshold in order to ensure acceptance and that this threshold depends directly on the rate of parasitism. The only evolutionarily stable strategy (ESS) combination is when hosts accept all signallers and parasites signal at their optimal signal intensity, which must be below the threshold. Supernormal manipulation by parasites is only evolutionarily stable under sufficiently low rates of parasitism. If the conditions for the ESS combination are not satisfied, rejector hosts can invade using signal intensity as a cue for identifying parasites. These qualitative predictions are discussed with respect to empirical evidence from parasitic mimicry systems that have been suggested to involve supernormal signalling, including evicting avian brood parasites and insect-mimicking Ophrys orchids. PMID:11749709

  11. Gastrointestinal parasite infestation.

    PubMed

    Abd El Bagi, Mohamed E; Sammak, Bassam M; Mohamed, Abdulrahman E; Al Karawi, Mohamed A; Al Shahed, Mona; Al Thagafi, Mohamed A

    2004-03-01

    Twenty-five percent of the world's population could be suffering parasitic infestation. Highest prevalence is in underdeveloped agricultural and rural areas in the tropical and subtropical regions. In some areas incidence may reach 90% of the population. In contrast, some major economic projects intended to promote local development have, paradoxically, caused parasitic proliferation, e.g. bilharziasis in Egypt and Sudan and Chagas disease in Brazil. The commonest cosmopolitan gastrointestinal parasite is Entamoeba histolytica. Some intestinal parasite are endemic in temperate climates, e.g. Entrobius vermicularis. The AIDS epidemic has increased the prevalence and severity of parasitic disease, particularly Strongyloides stercolaris. Tropical parasites are seen in Western people who travel to tropical countries. Radiology has acquired a major role in diagnosis and management of gastrointestinal parasite infestations and their complications.

  12. 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

  13. Cultivation of parasites

    PubMed Central

    Ahmed, Nishat Hussain

    2014-01-01

    Parasite cultivation techniques constitute a substantial segment of present-day study of parasites, especially of protozoa. Success in establishing in vitro and in vivo culture of parasites not only allows their physiology, behavior and metabolism to be studied dynamically, but also allows the nature of the antigenic molecules in the excretory and secretory products to be vigorously pursued and analyzed. The complex life-cycles of various parasites having different stages and host species requirements, particularly in the case of parasitic helminths, often make parasite cultivation an uphill assignment. Culturing of parasites depends on the combined expertise of all types of microbiological cultures. Different parasites require different cultivation conditions such as nutrients, temperature and even incubation conditions. Cultivation is an important method for diagnosis of many clinically important parasites, for example, Entamoeba histolytica, Trichomonas vaginalis, Leishmania spp., Strongyloides stercoralis and free-living amoebae. Many commercial systems like InPouch TV for T. vaginalis, microaerophilous stationary phase culture for Babesia bovis and Harada-Mori culture technique for larval-stage nematodes have been developed for the rapid diagnosis of the parasitic infections. Cultivation also has immense utility in the production of vaccines, testing vaccine efficacy, and antigen - production for obtaining serological reagents, detection of drug-resistance, screening of potential therapeutic agents and conducting epidemiological studies. Though in vitro cultivation techniques are used more often compared with in vivo techniques, the in vivo techniques are sometimes used for diagnosing some parasitic infections such as trypanosomiasis and toxoplasmosis. Parasite cultivation continues to be a challenging diagnostic option. This review provides an overview of intricacies of parasitic culture and update on popular methods used for cultivating parasites. PMID

  14. Malaria parasite clearance.

    PubMed

    White, Nicholas J

    2017-02-23

    Following anti-malarial drug treatment asexual malaria parasite killing and clearance appear to be first order processes. Damaged malaria parasites in circulating erythrocytes are removed from the circulation mainly by the spleen. Splenic clearance functions increase markedly in acute malaria. Either the entire infected erythrocytes are removed because of their reduced deformability or increased antibody binding or, for the artemisinins which act on young ring stage parasites, splenic pitting of drug-damaged parasites is an important mechanism of clearance. The once-infected erythrocytes returned to the circulation have shortened survival. This contributes to post-artesunate haemolysis that may follow recovery in non-immune hyperparasitaemic patients. As the parasites mature Plasmodium vivax-infected erythrocytes become more deformable, whereas Plasmodium falciparum-infected erythrocytes become less deformable, but they escape splenic filtration by sequestering in venules and capillaries. Sequestered parasites are killed in situ by anti-malarial drugs and then disintegrate to be cleared by phagocytic leukocytes. After treatment with artemisinin derivatives some asexual parasites become temporarily dormant within their infected erythrocytes, and these may regrow after anti-malarial drug concentrations decline. Artemisinin resistance in P. falciparum reflects reduced ring stage susceptibility and manifests as slow parasite clearance. This is best assessed from the slope of the log-linear phase of parasitaemia reduction and is commonly measured as a parasite clearance half-life. Pharmacokinetic-pharmacodynamic modelling of anti-malarial drug effects on parasite clearance has proved useful in predicting therapeutic responses and in dose-optimization.

  15. Parasites: evolution's neurobiologists.

    PubMed

    Adamo, Shelley Anne

    2013-01-01

    For millions of years, parasites have altered the behaviour of their hosts. Parasites can affect host behaviour by: (1) interfering with the host's normal immune-neural communication, (2) secreting substances that directly alter neuronal activity via non-genomic mechanisms and (3) inducing genomic- and/or proteomic-based changes in the brain of the host. Changes in host behaviour are often restricted to particular behaviours, with many other behaviours remaining unaffected. Neuroscientists can produce this degree of selectivity by targeting specific brain areas. Parasites, however, do not selectively attack discrete brain areas. Parasites typically induce a variety of effects in several parts of the brain. Parasitic manipulation of host behaviour evolved within the context of the manipulation of other host physiological systems (especially the immune system) that was required for a parasite's survival. This starting point, coupled with the fortuitous nature of evolutionary innovation and evolutionary pressures to minimize the costs of parasitic manipulation, likely contributed to the complex and indirect nature of the mechanisms involved in host behavioural control. Because parasites and neuroscientists use different tactics to control behaviour, studying the methods used by parasites can provide novel insights into how nervous systems generate and regulate behaviour. Studying how parasites influence host behaviour will also help us integrate genomic, proteomic and neurophysiological perspectives on behaviour.

  16. Sphingolipids in parasitic protozoa

    PubMed Central

    Zhang, Kai; Bangs, James D.; Beverley, Stephen M.

    2009-01-01

    The surface of most protozoan parasites relies heavily upon lipid-anchored molecules, to form protective barriers and play critical functions required for infectivity. Sphingolipids (SLs) play important roles through their abundance and involvement in membrane microdomain formation, as well as serving as the lipid anchor for many of these molecules, and in some but possibly not all species, as important signaling molecules. Interactions of parasite sphingolipid metabolism with that of the host may potentially contribute to parasite survival and/or host defense. In this chapter we summarize current knowledge of SL structure, synthesis and function in several of the major parasitic protozoan groups. PMID:20919659

  17. Intracellular Parasite Invasion Strategies

    NASA Astrophysics Data System (ADS)

    Sibley, L. D.

    2004-04-01

    Intracellular parasites use various strategies to invade cells and to subvert cellular signaling pathways and, thus, to gain a foothold against host defenses. Efficient cell entry, ability to exploit intracellular niches, and persistence make these parasites treacherous pathogens. Most intracellular parasites gain entry via host-mediated processes, but apicomplexans use a system of adhesion-based motility called ``gliding'' to actively penetrate host cells. Actin polymerization-dependent motility facilitates parasite migration across cellular barriers, enables dissemination within tissues, and powers invasion of host cells. Efficient invasion has brought widespread success to this group, which includes Toxoplasma, Plasmodium, and Cryptosporidium.

  18. PARASITES OF FISH

    EPA Science Inventory

    The intent of this chapter is to describe the parasites of importance to fishes maintained and used in laboratory settings. In contrast to the frist edition, the focus will be only on those parasites that pose a serious threat to or are common in fishes held in these confined en...

  19. Parasites and marine invasions

    USGS Publications Warehouse

    Torchin, M.E.; Lafferty, K.D.; Kuris, A.M.

    2002-01-01

    Introduced marine species are a major environmental and economic problem. The rate of these biological invasions has substantially increased in recent years due to the globalization of the world's economies. The damage caused by invasive species is often a result of the higher densities and larger sizes they attain compared to where they are native. A prominent hypothesis explaining the success of introduced species is that they are relatively free of the effects of natural enemies. Most notably, they may encounter fewer parasites in their introduced range compared to their native range. Parasites are ubiquitous and pervasive in marine systems, yet their role in marine invasions is relatively unexplored. Although data on parasites of marine organisms exist, the extent to which parasites can mediate marine invasions, or the extent to which invasive parasites and pathogens are responsible for infecting or potentially decimating native marine species have not been examined. In this review, we present a theoretical framework to model invasion success and examine the evidence for a relationship between parasite presence and the success of introduced marine species. For this, we compare the prevalence and species richness of parasites in several introduced populations of marine species with populations where they are native. We also discuss the potential impacts of introduced marine parasites on native ecosystems.

  20. Peroxiredoxins in Parasites

    PubMed Central

    Gretes, Michael C.; Poole, Leslie B.

    2012-01-01

    Abstract Significance: Parasite survival and virulence relies on effective defenses against reactive oxygen and nitrogen species produced by the host immune system. Peroxiredoxins (Prxs) are ubiquitous enzymes now thought to be central to such defenses and, as such, have potential value as drug targets and vaccine antigens. Recent Advances: Plasmodial and kinetoplastid Prx systems are the most extensively studied, yet remain inadequately understood. For many other parasites our knowledge is even less well developed. Through parasite genome sequencing efforts, however, the key players are being discovered and characterized. Here we describe what is known about the biochemistry, regulation, and cell biology of Prxs in parasitic protozoa, helminths, and fungi. At least one Prx is found in each parasite with a sequenced genome, and a notable theme is the common patterns of expression, localization, and functionality among sequence-similar Prxs in related species. Critical Issues: The nomenclature of Prxs from parasites is in a state of disarray, causing confusion and making comparative inferences difficult. Here we introduce a systematic Prx naming convention that is consistent between organisms and informative about structural and evolutionary relationships. Future Directions: The new nomenclature should stimulate the crossfertilization of ideas among parasitologists and with the broader redox research community. The diverse parasite developmental stages and host environments present complex systems in which to explore the variety of roles played by Prxs, with a view toward parlaying what is learned into novel therapies and vaccines that are urgently needed. Antioxid. Redox Signal. 17, 608–633. PMID:22098136

  1. 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.

  2. Bird brood parasitism.

    PubMed

    Stevens, Martin

    2013-10-21

    For many animals, the effort to rear their young is considerable. In birds, this often includes building nests, incubating eggs, feeding the chicks, and protecting them from predators. Perhaps for this reason, about 1% of birds (around 100 species) save themselves the effort and cheat instead. They are obligate brood parasites, laying their eggs in the nests of other species and leaving the hosts or foster parents to rear the foreign chicks for them. Some birds also cheat on individuals of the same species (intraspecific brood parasitism). Intraspecific brood parasitism has been reported in around 200 species, but is likely to be higher, as it can often only be detected by genetic analyses.

  3. [Parasitism and ecological parasitology].

    PubMed

    Balashov, Iu S

    2011-01-01

    Parasitism as one of the life modes is a general biological phenomenon and is a characteristic of all viruses, many taxa of bacteria, fungi, protists, metaphytes, and metazoans. Zooparasitology is focused on studies of parasitic animals, particularly, on their taxonomy, anatomy, life cycles, host-parasite relations, biocoenotic connections, and evolution. Ecological parasitology is a component of ecology, as the scientific study of the relation of living organisms with each other and their surroundings. In the present paper, critical analysis of the problems, main postulates, and terminology of the modern ecological parasitology is given.

  4. Metabolomics and protozoan parasites.

    PubMed

    Paget, Timothy; Haroune, Nicolas; Bagchi, Sushmita; Jarroll, Edward

    2013-06-01

    In this review, we examine the state-of-the-art technologies (gas and liquid chromatography, mass spectroscopy and nuclear magnetic resonance, etc.) in the well-established area of metabolomics especially as they relate to protozoan parasites.

  5. Parasitic Diseases: Glossary

    MedlinePlus

    ... make it easier to diagnose certain infections/diseases. Protozoa: Single-celled, microscopic organisms that can perform all necessary functions of metabolism and reproduction. Some protozoa are free-living, while others parasitize other organisms ...

  6. Women and Parasitic Diseases

    MedlinePlus

    ... Travelers Women Health Professionals Public Health Departments Laboratory Science ... Infection with Toxoplasma gondii , a parasite found in undercooked meat, cat feces, soil, and untreated water can lead to severe brain ...

  7. Cytoskeleton of Apicomplexan Parasites

    PubMed Central

    Morrissette, Naomi S.; Sibley, L. David

    2002-01-01

    The Apicomplexa are a phylum of diverse obligate intracellular parasites including Plasmodium spp., the cause of malaria; Toxoplasma gondii and Cryptosporidium parvum, opportunistic pathogens of immunocompromised individuals; and Eimeria spp. and Theileria spp., parasites of considerable agricultural importance. These protozoan parasites share distinctive morphological features, cytoskeletal organization, and modes of replication, motility, and invasion. This review summarizes our current understanding of the cytoskeletal elements, the properties of cytoskeletal proteins, and the role of the cytoskeleton in polarity, motility, invasion, and replication. We discuss the unusual properties of actin and myosin in the Apicomplexa, the highly stereotyped microtubule populations in apicomplexans, and a network of recently discovered novel intermediate filament-like elements in these parasites. PMID:11875126

  8. Parasites and human evolution.

    PubMed

    Perry, George H

    2014-01-01

    Our understanding of human evolutionary and population history can be advanced by ecological and evolutionary studies of our parasites. Many parasites flourish only in the presence of very specific human behaviors and in specific habitats, are wholly dependent on us, and have evolved with us for thousands or millions of years. Therefore, by asking when and how we first acquired those parasites, under which environmental and cultural conditions we are the most susceptible, and how the parasites have evolved and adapted to us and we in response to them, we can gain considerable insight into our own evolutionary history. As examples, the tapeworm life cycle is dependent on our consumption of meat, the divergence of body and head lice may have been subsequent to the development of clothing, and malaria hyperendemicity may be associated with agriculture. Thus, the evolutionary and population histories of these parasites are likely intertwined with critical aspects of human biology and culture. Here I review the mechanics of these and multiple other parasite proxies for human evolutionary history and discuss how they currently complement our fossil, archeological, molecular, linguistic, historical, and ethnographic records. I also highlight potential future applications of this promising model for the field of evolutionary anthropology.

  9. 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.

  10. Comparative analysis of antiviral responses in Brachypodium distachyon and Setaria viridis reveals conserved and unique outcomes among C3 and C4 plant defenses.

    PubMed

    Mandadi, Kranthi K; Pyle, Jesse D; Scholthof, Karen-Beth G

    2014-11-01

    Viral diseases cause significant losses in global agricultural production, yet little is known about grass antiviral defense mechanisms. We previously reported on host immune responses triggered by Panicum mosaic virus (PMV) and its satellite virus (SPMV) in the model C3 grass Brachypodium distachyon. To aid comparative analyses of C3 and C4 grass antiviral defenses, here, we establish B. distachyon and Setaria viridis (a C4 grass) as compatible hosts for seven grass-infecting viruses, including PMV and SPMV, Brome mosaic virus, Barley stripe mosaic virus, Maize mild mottle virus, Sorghum yellow banding virus, Wheat streak mosaic virus (WSMV), and Foxtail mosaic virus (FoMV). Etiological and molecular characterization of the fourteen grass-virus pathosystems showed evidence for conserved crosstalk among salicylic acid (SA), jasmonic acid, and ethylene pathways in B. distachyon and S. viridis. Strikingly, expression of PHYTOALEXIN DEFICIENT4, an upstream modulator of SA signaling, was consistently suppressed during most virus infections in B. distachyon and S. viridis. Hierarchical clustering analyses further identified unique antiviral responses triggered by two morphologically similar viruses, FoMV and WSMV, and uncovered other host-dependent effects. Together, the results of this study establish B. distachyon and S. viridis as models for the analysis of plant-virus interactions and provide the first framework for conserved and unique features of C3 and C4 grass antiviral defenses.

  11. Serological diagnosis of Parelaphostrongylus tenuis infection in white-tailed deer and identification of a potentially unique parasite antigen.

    PubMed

    Ogunremi, O; Lankester, M; Kendall, J; Gajadhar, A

    1999-02-01

    Serological diagnosis of Parelaphostrongylus tenuis infection should offer many advantages over the currently used method of fecal analysis that relies on a patent infection. Toward this end, we investigated the presence of P. tenuis-specific antibodies in experimentally infected white-tailed deer (WTD) and of unique P. tenuis antigens that may be exploited for serodiagnosis. WTD infected with 6, 20 or 100-150 P. tenuis third-stage larvae (L3) had anti-parasite antibodies from as early as 21 days postinoculation (dpi) until the end of the experiment (147 dpi). Peak anti-P. tenuis enzyme-linked immunosorbent assay (ELISA) titers in individual animals ranged from 1:70 to 1:5,700. Serum from infected WTD reacted with 5 distinct P. tenuis L3 antigens (105, 45, 37, 32, and 19 kDa) as detected by the immunoblotting technique. Serum from caribou infected with Parelaphostrongylus andersoni or Elaphostrongylus rangiferi reacted with all antigens except the 37-kDa antigen of L3, indicating that it may be unique to P. tenuis and can serve as a serodiagnostic antigen. The 37-kDa antigen appears to be present in the adult P. tenuis but not adult E. rangiferi or E. cervi. The development of an ELISA utilizing the unique antigen of P. tenuis should lead to a reliable diagnostic assay for P. tenuis infection in WTD.

  12. C-cinnamoyl glycosides as a new class of anti-filarial agents.

    PubMed

    Roy, Priya; Dhara, Debashis; Parida, Pravat Kumar; Kar, Rajiv Kumar; Bhunia, Anirban; Jana, Kuladip; Sinha Babu, Santi P; Misra, Anup Kumar

    2016-05-23

    A series of C-cinnamoyl glycosides has been synthesized in good yield by the BF3·OEt2 catalyzed aldol condensation of C-glycosylated acetone derivative with a variety of aromatic aldehydes. The synthesized compounds were evaluated for their potential as anti-filarial agents against bovine filarial parasite Setaria cervi and human filariid Wuchereria bancrofti using a number of biological assays such as relative movability (RM) assessment and MTT reduction assay. Among twenty seven test compounds six compounds were found active in terms of MIC, IC50 and LC50 values. Further biological studies were carried out using three lead compounds because of their significantly low MIC values and IC50 values compared to the standard anti-filarial drug Ivermectin. In addition, structure activity relationship study of the test compounds has been carried out using 3D-QSAR analysis.

  13. [Main parasitic skin disorders].

    PubMed

    Bernigaud, C; Monsel, G; Delaunay, P; Do-Pham, G; Foulet, F; Botterel, F; Chosidow, O

    2017-01-01

    Cutaneous parasitic skin diseases are frequent in human pathology. There are few reliable epidemiological data on the prevalence and/or incidence of such diseases. Skin parasites are cosmopolitan but their global distribution is heterogenous; prevalence is especially high in subtropical and tropical countries. They are mainly due to arthropods (insects and mites). Many species of parasites are involved, explaining the diversity of their clinical signs. The most common are caused by ectoparasites such as scabies or pediculosis (head lice, body lice and pubic lice). Clinical signs may be related to the penetration of the parasite under the skin, its development, the inoculation of venom or allergic symptoms. Diagnosis can be easy when clinical signs are pathognomonic (e.g. burrows in the interdigital web spaces in scabies) or sometimes more difficult. Some epidemiological characteristics (diurnal or nocturnal bite, seasonality) and specific clinical presentation (single or multiple bites, linear or grouped lesions) can be a great diagnostic help. Modern non-invasive tools (dermoscopy or confocal microscopy) will play an important role in the future but the eye and experience of the specialist (dermatologist, parasitologist, infectious disease specialist or entomologist) remains for the time the best way to guide or establish a diagnosis. For most skin parasites, therapeutic proposals are rarely based on studies of high level of evidence or randomized trials but more on expert recommendations or personal experience.

  14. Plants, endosymbionts and parasites

    PubMed Central

    Nagamune, Kisaburo; Xiong, Liming; Chini, Eduardo

    2008-01-01

    It was recently discovered that the protozoan parasite, Toxoplasma gondii produces and uses the plant hormone, abscisic acid (ABA), for communication. Following intracellular replication, ABA production influences the timing of parasite egress from the host cell. This density-dependent signal may serve to coordinate exit from the host cell in a synchronous manner by triggering calcium-dependent activation of motility. In the absence of ABA production, parasites undergo differentiation to the semidormant, tissue cyst. The pathway for ABA production in T. gondii may be derived from a relict endosymbiont, acquired by ingestion of a red algal cell. Although the parasite has lost the capacity for photosynthesis, the plant-like nature of this signaling pathway may be exploited to develop new drugs. In support of this idea, an inhibitor of ABA biosynthesis protected mice against lethal infection with T. gondii. Here, we compare the role of ABA in parasites to its activities in plants, where it is know to control development and stress responses. PMID:19513200

  15. Niche metabolism in parasitic protozoa.

    PubMed

    Ginger, Michael L

    2006-01-29

    Complete or partial genome sequences have recently become available for several medically and evolutionarily important parasitic protozoa. Through the application of bioinformatics complete metabolic repertoires for these parasites can be predicted. For experimentally intractable parasites insight provided by metabolic maps generated in silico has been startling. At its more extreme end, such bioinformatics reckoning facilitated the discovery in some parasites of mitochondria remodelled beyond previous recognition, and the identification of a non-photosynthetic chloroplast relic in malarial parasites. However, for experimentally tractable parasites, mapping of the general metabolic terrain is only a first step in understanding how the parasite modulates its streamlined, yet still often puzzlingly complex, metabolism in order to complete life cycles within host, vector, or environment. This review provides a comparative overview and discussion of metabolic strategies used by several different parasitic protozoa in order to subvert and survive host defences, and illustrates how genomic data contribute to the elucidation of parasite metabolism.

  16. Ecosystem consequences of fish parasites

    USGS Publications Warehouse

    Lafferty, Kevin D.

    2008-01-01

    In most aquatic ecosystems, fishes are hosts to parasites and, sometimes, these parasites can affect fish biology. Some of the most dramatic cases occur when fishes are intermediate hosts for larval parasites. For example, fishes in southern California estuaries are host to many parasites. The most common of these parasites, Euhaplorchis californiensis, infects the brain of the killifish Fundulus parvipinnis and alters its behaviour, making the fish 10–30 times more susceptible to predation by the birds that serve as its definitive host. Parasites like E. californiensis are embedded in food webs because they require trophic transmission. In the Carpinteria Salt Marsh estuarine food web, parasites dominate the links and comprise substantial amount of biomass. Adding parasites to food webs alters important network statistics such as connectance and nestedness. Furthermore, some free-living stages of parasites are food items for free-living species. For instance, fishes feed on trematode cercariae. Being embedded in food webs makes parasites sensitive to changes in the environment. In particular, fishing and environmental disturbance, by reducing fish populations, may reduce parasite populations. Indirect evidence suggests a decrease in parasites in commercially fished species over the past three decades. In addition, environmental degradation can affect fish parasites. For these reasons, parasites in fishes may serve as indicators of environmental impacts.

  17. Internal parasites of reptiles.

    PubMed

    Raś-Noryńska, Małgorzata; Sokół, Rajmund

    2015-01-01

    Nowadays a growing number of exotic reptiles are kept as pets. The aim of this study was to determine the species of parasites found in reptile patients of veterinary practices in Poland. Fecal samples obtained from 76 lizards, 15 turtles and 10 snakes were examined by flotation method and direct smear stained with Lugol's iodine. In 63 samples (62.4%) the presence of parasite eggs and oocysts was revealed. Oocysts of Isospora spp. (from 33% to 100% of the samples, depending on the reptilian species) and Oxyurids eggs (10% to 75%) were predominant. In addition, isolated Eimeria spp. oocysts and Giardia intestinalis cysts were found, as well as Strongylus spp. and Hymenolepis spp. eggs. Pet reptiles are often infected with parasites, some of which are potentially dangerous to humans. A routine parasitological examination should be done in such animals.

  18. Malaria Parasites: The Great Escape

    PubMed Central

    Rénia, Laurent; Goh, Yun Shan

    2016-01-01

    Parasites of the genus Plasmodium have a complex life cycle. They alternate between their final mosquito host and their intermediate hosts. The parasite can be either extra- or intracellular, depending on the stage of development. By modifying their shape, motility, and metabolic requirements, the parasite adapts to the different environments in their different hosts. The parasite has evolved to escape the multiple immune mechanisms in the host that try to block parasite development at the different stages of their development. In this article, we describe the mechanisms reported thus far that allow the Plasmodium parasite to evade innate and adaptive immune responses. PMID:27872623

  19. Microarray in parasitic infections

    PubMed Central

    Sehgal, Rakesh; Misra, Shubham; Anand, Namrata; Sharma, Monika

    2012-01-01

    Modern biology and genomic sciences are rooted in parasitic disease research. Genome sequencing efforts have provided a wealth of new biological information that promises to have a major impact on our understanding of parasites. Microarrays provide one of the major high-throughput platforms by which this information can be exploited in the laboratory. Many excellent reviews and technique articles have recently been published on applying microarrays to organisms for which fully annotated genomes are at hand. However, many parasitologists work on organisms whose genomes have been only partially sequenced. This review is mainly focused on how to use microarray in these situations. PMID:23508469

  20. Ungulate malaria parasites

    PubMed Central

    Templeton, Thomas J.; Asada, Masahito; Jiratanh, Montakan; Ishikawa, Sohta A.; Tiawsirisup, Sonthaya; Sivakumar, Thillaiampalam; Namangala, Boniface; Takeda, Mika; Mohkaew, Kingdao; Ngamjituea, Supawan; Inoue, Noboru; Sugimoto, Chihiro; Inagaki, Yuji; Suzuki, Yasuhiko; Yokoyama, Naoaki; Kaewthamasorn, Morakot; Kaneko, Osamu

    2016-01-01

    Haemosporida parasites of even-toed ungulates are diverse and globally distributed, but since their discovery in 1913 their characterization has relied exclusively on microscopy-based descriptions. In order to bring molecular approaches to bear on the identity and evolutionary relationships of ungulate malaria parasites, we conducted Plasmodium cytb-specific nested PCR surveys using blood from water buffalo in Vietnam and Thailand, and goats in Zambia. We found that Plasmodium is readily detectable from water buffalo in these countries, indicating that buffalo Plasmodium is distributed in a wider region than India, which is the only area in which buffalo Plasmodium has been reported. Two types (I and II) of Plasmodium sequences were identified from water buffalo and a third type (III) was isolated from goat. Morphology of the parasite was confirmed in Giemsa-reagent stained blood smears for the Type I sample. Complete mitochondrial DNA sequences were isolated and used to infer a phylogeny in which ungulate malaria parasites form a monophyletic clade within the Haemosporida, and branch prior to the clade containing bird, lizard and other mammalian Plasmodium. Thus it is likely that host switching of Plasmodium from birds to mammals occurred multiple times, with a switch to ungulates independently from other mammalian Plasmodium. PMID:26996979

  1. Genomics of apicomplexan parasites.

    PubMed

    Swapna, Lakshmipuram Seshadri; Parkinson, John

    2017-02-22

    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.

  2. A Passion for Parasites

    PubMed Central

    Englund, Paul T.

    2014-01-01

    I knew nothing and had thought nothing about parasites until 1971. In fact, if you had asked me before then, I might have commented that parasites were rather disgusting. I had been at the Johns Hopkins School of Medicine for three years, and I was on the lookout for a new project. In 1971, I came across a paper in the Journal of Molecular Biology by Larry Simpson, a classmate of mine in graduate school. Larry's paper described a remarkable DNA structure known as kinetoplast DNA (kDNA), isolated from a parasite. kDNA, the mitochondrial genome of trypanosomatids, is a DNA network composed of several thousand interlocked DNA rings. Almost nothing was known about it. I was looking for a project on DNA replication, and I wanted it to be both challenging and important. I had no doubt that working with kDNA would be a challenge, as I would be exploring uncharted territory. I was also sure that the project would be important when I learned that parasites with kDNA threaten huge populations in underdeveloped tropical countries. Looking again at Larry's paper, I found the electron micrographs of the kDNA networks to be rather beautiful. I decided to take a chance on kDNA. Little did I know then that I would devote the next forty years of my life to studying kDNA replication. PMID:25336639

  3. Integrative analysis and expression profiling of secondary cell wall genes in C4 biofuel model Setaria italica reveals targets for lignocellulose bioengineering

    PubMed Central

    Muthamilarasan, Mehanathan; Khan, Yusuf; Jaishankar, Jananee; Shweta, Shweta; Lata, Charu; Prasad, Manoj

    2015-01-01

    Several underutilized grasses have excellent potential for use as bioenergy feedstock due to their lignocellulosic biomass. Genomic tools have enabled identification of lignocellulose biosynthesis genes in several sequenced plants. However, the non-availability of whole genome sequence of bioenergy grasses hinders the study on bioenergy genomics and their genomics-assisted crop improvement. Foxtail millet (Setaria italica L.; Si) is a model crop for studying systems biology of bioenergy grasses. In the present study, a systematic approach has been used for identification of gene families involved in cellulose (CesA/Csl), callose (Gsl) and monolignol biosynthesis (PAL, C4H, 4CL, HCT, C3H, CCoAOMT, F5H, COMT, CCR, CAD) and construction of physical map of foxtail millet. Sequence alignment and phylogenetic analysis of identified proteins showed that monolignol biosynthesis proteins were highly diverse, whereas CesA/Csl and Gsl proteins were homologous to rice and Arabidopsis. Comparative mapping of foxtail millet lignocellulose biosynthesis genes with other C4 panicoid genomes revealed maximum homology with switchgrass, followed by sorghum and maize. Expression profiling of candidate lignocellulose genes in response to different abiotic stresses and hormone treatments showed their differential expression pattern, with significant higher expression of SiGsl12, SiPAL2, SiHCT1, SiF5H2, and SiCAD6 genes. Further, due to the evolutionary conservation of grass genomes, the insights gained from the present study could be extrapolated for identifying genes involved in lignocellulose biosynthesis in other biofuel species for further characterization. PMID:26583030

  4. Phosphate Concentration and Arbuscular Mycorrhizal Colonisation Influence the Growth, Yield and Expression of Twelve PHT1 Family Phosphate Transporters in Foxtail Millet (Setaria italica)

    PubMed Central

    Ceasar, S. Antony; Hodge, Angela; Baker, Alison; Baldwin, Stephen A.

    2014-01-01

    Phosphorus (P) is an essential element which plays several key roles in all living organisms. Setaria italica (foxtail millet) is a model species for panacoid grasses including several millet species widely grown in arid regions of Asia and Africa, and for the bioenergy crop switchgrass. The growth responses of S. italica to different levels of inorganic phosphate (Pi) and to colonisation with the arbuscular mycorrhizal fungus Funneliformis mosseae (syn. Glomus mosseae) were studied. Phosphate is taken up from the environment by the PHT1 family of plant phosphate transporters, which have been well characterized in several plant species. Bioinformatic analysis identified 12 members of the PHT1 gene family (SiPHT1;1-1;12) in S. italica, and RT and qPCR analysis showed that most of these transporters displayed specific expression patterns with respect to tissue, phosphate status and arbuscular mycorrhizal colonisation. SiPHT1;2 was found to be expressed in all tissues and in all growth conditions tested. In contrast, expression of SiPHT1;4 was induced in roots after 15 days growth in hydroponic medium of low Pi concentration. Expression of SiPHT1;8 and SiPHT1;9 in roots was selectively induced by colonisation with F. mosseae. SiPHT1;3 and SiPHT1;4 were found to be predominantly expressed in leaf and root tissues respectively. Several other transporters were expressed in shoots and leaves during growth in low Pi concentrations. This study will form the basis for the further characterization of these transporters, with the long term goal of improving the phosphate use efficiency of foxtail millet. PMID:25251671

  5. Evaluation of water-use efficiency in foxtail millet (Setaria italica) using visible-near infrared and thermal spectral sensing techniques.

    PubMed

    Wang, Meng; Ellsworth, Patrick Z; Zhou, Jianfeng; Cousins, Asaph B; Sankaran, Sindhuja

    2016-05-15

    Water limitations decrease stomatal conductance (g(s)) and, in turn, photosynthetic rate (A(net)), resulting in decreased crop productivity. The current techniques for evaluating these physiological responses are limited to leaf-level measures acquired by measuring leaf-level gas exchange. In this regard, proximal sensing techniques can be a useful tool in studying plant biology as they can be used to acquire plant-level measures in a high-throughput manner. However, to confidently utilize the proximal sensing technique for high-throughput physiological monitoring, it is important to assess the relationship between plant physiological parameters and the sensor data. Therefore, in this study, the application of rapid sensing techniques based on thermal imaging and visual-near infrared spectroscopy for assessing water-use efficiency (WUE) in foxtail millet (Setaria italica (L.) P. Beauv) was evaluated. The visible-near infrared spectral reflectance (350-2500 nm) and thermal (7.5-14 µm) data were collected at regular intervals from well-watered and drought-stressed plants in combination with other leaf physiological parameters (transpiration rate-E, A(net), g(s), leaf carbon isotopic signature-δ(13)C(leaf), WUE). Partial least squares regression (PLSR) analysis was used to predict leaf physiological measures based on the spectral data. The PLSR modeling on the hyperspectral data yielded accurate and precise estimates of leaf E, gs, δ(13)C(leaf), and WUE with coefficient of determination in a range of 0.85-0.91. Additionally, significant differences in average leaf temperatures (~1°C) measured with a thermal camera were observed between well-watered plants and drought-stressed plants. In summary, the visible-near infrared reflectance data, and thermal images can be used as a potential rapid technique for evaluating plant physiological responses such as WUE.

  6. Metabolic Reconstruction of Setaria italica: A Systems Biology Approach for Integrating Tissue-Specific Omics and Pathway Analysis of Bioenergy Grasses

    PubMed Central

    de Oliveira Dal'Molin, Cristiana G.; Orellana, Camila; Gebbie, Leigh; Steen, Jennifer; Hodson, Mark P.; Chrysanthopoulos, Panagiotis; Plan, Manuel R.; McQualter, Richard; Palfreyman, Robin W.; Nielsen, Lars K.

    2016-01-01

    The urgent need for major gains in industrial crops productivity and in biofuel production from bioenergy grasses have reinforced attention on understanding C4 photosynthesis. Systems biology studies of C4 model plants may reveal important features of C4 metabolism. Here we chose foxtail millet (Setaria italica), as a C4 model plant and developed protocols to perform systems biology studies. As part of the systems approach, we have developed and used a genome-scale metabolic reconstruction in combination with the use of multi-omics technologies to gain more insights into the metabolism of S. italica. mRNA, protein, and metabolite abundances, were measured in mature and immature stem/leaf phytomers, and the multi-omics data were integrated into the metabolic reconstruction framework to capture key metabolic features in different developmental stages of the plant. RNA-Seq reads were mapped to the S. italica resulting for 83% coverage of the protein coding genes of S. italica. Besides revealing similarities and differences in central metabolism of mature and immature tissues, transcriptome analysis indicates significant gene expression of two malic enzyme isoforms (NADP- ME and NAD-ME). Although much greater expression levels of NADP-ME genes are observed and confirmed by the correspondent protein abundances in the samples, the expression of multiple genes combined to the significant abundance of metabolites that participates in C4 metabolism of NAD-ME and NADP-ME subtypes suggest that S. italica may use mixed decarboxylation modes of C4 photosynthetic pathways under different plant developmental stages. The overall analysis also indicates different levels of regulation in mature and immature tissues in carbon fixation, glycolysis, TCA cycle, amino acids, fatty acids, lignin, and cellulose syntheses. Altogether, the multi-omics analysis reveals different biological entities and their interrelation and regulation over plant development. With this study, we demonstrated

  7. Metabolic Reconstruction of Setaria italica: A Systems Biology Approach for Integrating Tissue-Specific Omics and Pathway Analysis of Bioenergy Grasses.

    PubMed

    de Oliveira Dal'Molin, Cristiana G; Orellana, Camila; Gebbie, Leigh; Steen, Jennifer; Hodson, Mark P; Chrysanthopoulos, Panagiotis; Plan, Manuel R; McQualter, Richard; Palfreyman, Robin W; Nielsen, Lars K

    2016-01-01

    The urgent need for major gains in industrial crops productivity and in biofuel production from bioenergy grasses have reinforced attention on understanding C4 photosynthesis. Systems biology studies of C4 model plants may reveal important features of C4 metabolism. Here we chose foxtail millet (Setaria italica), as a C4 model plant and developed protocols to perform systems biology studies. As part of the systems approach, we have developed and used a genome-scale metabolic reconstruction in combination with the use of multi-omics technologies to gain more insights into the metabolism of S. italica. mRNA, protein, and metabolite abundances, were measured in mature and immature stem/leaf phytomers, and the multi-omics data were integrated into the metabolic reconstruction framework to capture key metabolic features in different developmental stages of the plant. RNA-Seq reads were mapped to the S. italica resulting for 83% coverage of the protein coding genes of S. italica. Besides revealing similarities and differences in central metabolism of mature and immature tissues, transcriptome analysis indicates significant gene expression of two malic enzyme isoforms (NADP- ME and NAD-ME). Although much greater expression levels of NADP-ME genes are observed and confirmed by the correspondent protein abundances in the samples, the expression of multiple genes combined to the significant abundance of metabolites that participates in C4 metabolism of NAD-ME and NADP-ME subtypes suggest that S. italica may use mixed decarboxylation modes of C4 photosynthetic pathways under different plant developmental stages. The overall analysis also indicates different levels of regulation in mature and immature tissues in carbon fixation, glycolysis, TCA cycle, amino acids, fatty acids, lignin, and cellulose syntheses. Altogether, the multi-omics analysis reveals different biological entities and their interrelation and regulation over plant development. With this study, we demonstrated

  8. Parasitic Diseases With Cutaneous Manifestations.

    PubMed

    Ash, Mark M; Phillips, Charles M

    2016-01-01

    Parasitic diseases result in a significant global health burden. While often thought to be isolated to returning travelers, parasitic diseases can also be acquired locally in the United States. Therefore, clinicians must be aware of the cutaneous manifestations of parasitic diseases to allow for prompt recognition, effective management, and subsequent mitigation of complications. This commentary also reviews pharmacologic treatment options for several common diseases.

  9. 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

  10. microRNAs in parasites and parasite infection.

    PubMed

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

    2013-03-01

    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.

  11. Metazoan Parasites of Antarctic Fishes.

    PubMed

    Oğuz, Mehmet Cemal; Tepe, Yahya; Belk, Mark C; Heckmann, Richard A; Aslan, Burçak; Gürgen, Meryem; Bray, Rodney A; Akgül, Ülker

    2015-06-01

    To date, there have been nearly 100 papers published on metazoan parasites of Antarctic fishes, but there has not yet been any compilation of a species list of fish parasites for this large geographic area. Herein, we provide a list of all documented occurrences of monogenean, cestode, digenean, acanthocephalan, nematode, and hirudinean parasites of Antarctic fishes. The list includes nearly 250 parasite species found in 142 species of host fishes. It is likely that there are more species of fish parasites, which are yet to be documented from Antarctic waters.

  12. Protein moonlighting in parasitic protists.

    PubMed

    Ginger, Michael L

    2014-12-01

    Reductive evolution during the adaptation to obligate parasitism and expansions of gene families encoding virulence factors are characteristics evident to greater or lesser degrees in all parasitic protists studied to date. Large evolutionary distances separate many parasitic protists from the yeast and animal models upon which classic views of eukaryotic biochemistry are often based. Thus a combination of evolutionary divergence, niche adaptation and reductive evolution means the biochemistry of parasitic protists is often very different from their hosts and to other eukaryotes generally, making parasites intriguing subjects for those interested in the phenomenon of moonlighting proteins. In common with other organisms, the contribution of protein moonlighting to parasite biology is only just emerging, and it is not without controversy. Here, an overview of recently identified moonlighting proteins in parasitic protists is provided, together with discussion of some of the controversies.

  13. Parasite transmission through suspension feeding.

    PubMed

    Ben-Horin, Tal; Bidegain, Gorka; Huey, Lauren; Narvaez, Diego A; Bushek, David

    2015-10-01

    Suspension-feeding bivalve molluscs are confronted with a wide range of materials in the benthic marine environment. These materials include various sized plankton and the organic material derived from it, macroalgae, detritus and a diversity of microbial parasites that have adapted life stages to survive in the water column. For bivalve parasites to infect hosts though, they must first survive and remain infectious in the water column to make initial contact with hosts, and once in contact, enter and overcome elaborate pathways for particle sorting and selection. Even past these defenses, bivalve parasites are challenged with efficient systems of mechanical and chemical digestion and highly evolved systems of innate immunity. Here we review how bivalve parasites evade these hurdles to complete their life cycles and establish within bivalve hosts. We broadly cover significant viral, bacterial, and protozoan parasites of marine bivalve molluscs, and illustrate the emergent properties of these host-parasite systems where parasite transmission occurs through suspension feeding.

  14. Parasites and Foodborne Illness

    MedlinePlus

    ... Administrative Forms Standard Forms Skip Navigation Z7_0Q0619C0JGR010IFST1G5B10H1 Web Content Viewer (JSR 286) Actions ${title} Loading... / Topics / ... and Disease / Parasites and Foodborne Illness Z7_0Q0619C0JGR010IFST1G5B10H3 Web Content Viewer (JSR 286) Actions ${title} Loading... Z7_ ...

  15. Parasitic Myoma After Morcellation

    PubMed Central

    Sinha, Rakesh; Sundaram, Meenakshi; Lakhotia, Smita; Kadam, Pratima; Rao, Gayatri; Mahajan, Chaitali

    2009-01-01

    We report an interesting case of parasitic fibroid which developed from a morcellation remnant following laparoscopic myomectomy. The patient presented with incidental finding of pelvic mass in 2005. She underwent laparoscopic myomectomy for a myoma extending from the Pouch of Douglas to both sides of broad ligament. She subsequently presented with abdominal pain 3 years later in 2008. She underwent total laparoscopic hysterectomy with removal of broad ligament fibroids. During her hysterectomy, a right lumbar mass attached to the omentum was detected, which was excised laparoscopically. Histopathology of the mass confirmed it to be consistent with leiomyoma. This mass could probably be a morcellation remnant that has grown to this size taking blood supply from the omentum. We report this case to emphasize that all tissue pieces that are morcellated should be diligently removed. Even small bits displaced into the upper abdomen can result in parasitic fibroids. Thus, it can be concluded that parasitic myomas can arise from morcellated remnants and grow depending on the blood supply. PMID:22442523

  16. Nutrition and parasite interaction.

    PubMed

    Coop, R L; Holmes, P H

    1996-01-01

    This overview focuses on the interaction between nutritional status and gastrointestinal nematode infection in ruminants and considers: (i) the influence of the parasite on host metabolism; and (ii) the effect of host nutrition on the establishment and survival of parasite populations, the development of the host-immune response and the pathophysiology of infection. Gastrointestinal nematodes reduce voluntary feed intake and efficiency of feed utilisation, a key feature being an increased endogenous loss of protein into the gastrointestinal tract. Overall there is movement of protein from productive processes into repair of the gastrointestinal tract, synthesis of plasma proteins and mucoprotein production. Although reduction in feed intake is a major factor contributing to the reduced performance of parasitised ruminants, the underlying mechanisms of the anorexia are poorly understood. Supplementation of the diet with additional protein does not appear to affect initial establishment of nematode infections but the pathophysiological consequences are generally more severe on lower planes of protein nutrition. The main effect of protein supplementation is to increase the rate of acquisition of immunity and increase resistance to reinfection and this has been associated with an enhanced cellular immune response in the gastrointestinal mucosa. The unresponsiveness of the young lamb can be improved by dietary protein supplementation. Recent trials have shown that growing sheep offered a free choice between a low and a high protein ration are able to modify their diet selection in order to alleviate the increase in protein requirements which result from gastrointestinal nematode infection. Studies on the influence of nutrition on the expression of genotype have shown that the benefits of a superior genotype are not lost on a low protein diet whereas a high protein diet can partially emeliorate the disadvantages of an inferior genotype. In addition to dietary protein

  17. Immune Responses in Parasitic Diseases

    DTIC Science & Technology

    1982-09-01

    RESPONSES IN PARASITIC DISEASES Final Scientific Report Daniel J. Stechschulte, M.D. Herbert B. Lindsley, M.D. September 1982 (July 1974 - December 1979...REPORT & PERIOD COVERED IMMUNE RESPONSES IN PARASITIC DISEASES Final Report July 1977 - Dec. 1979 6. PERFORMING ORG. REPORT NUMBER S 4 7. AUTNIOR(a) 6...DAMD 17-74-C-4136 AD_______________ IMMUNE RESPONSES IN PARASITIC DISEASES Final Scientific Report Daniel J. Stechschulte, M.D. Herbert B. Lindsley

  18. Unexpected hosts: imaging parasitic diseases.

    PubMed

    Rodríguez Carnero, Pablo; Hernández Mateo, Paula; Martín-Garre, Susana; García Pérez, Ángela; Del Campo, Lourdes

    2017-02-01

    Radiologists seldom encounter parasitic diseases in their daily practice in most of Europe, although the incidence of these diseases is increasing due to migration and tourism from/to endemic areas. Moreover, some parasitic diseases are still endemic in certain European regions, and immunocompromised individuals also pose a higher risk of developing these conditions. This article reviews and summarises the imaging findings of some of the most important and frequent human parasitic diseases, including information about the parasite's life cycle, pathophysiology, clinical findings, diagnosis, and treatment. We include malaria, amoebiasis, toxoplasmosis, trypanosomiasis, leishmaniasis, echinococcosis, cysticercosis, clonorchiasis, schistosomiasis, fascioliasis, ascariasis, anisakiasis, dracunculiasis, and strongyloidiasis. The aim of this review is to help radiologists when dealing with these diseases or in cases where they are suspected. Teaching Points • Incidence of parasitic diseases is increasing due to migratory movements and travelling. • Some parasitic diseases are still endemic in certain regions in Europe. • Parasitic diseases can have complex life cycles often involving different hosts. • Prompt diagnosis and treatment is essential for patient management in parasitic diseases. • Radiologists should be able to recognise and suspect the most relevant parasitic diseases.

  19. [Parasitic dead-end: update].

    PubMed

    Magnaval, J F

    2006-08-01

    Parasitic dead-ends occur when a parasite is unable to establish a permanent interaction in an unnatural host. Although the likelihood of successful reproduction by the pathogenic agent is nul, parasitic dead-end heralds capture of new parasites and therefore expansion of the host range. Angiostrongyliasis due to A. cantonensis or A. costaricensis, anisakiasis, Ancylostoma caninum infection, gnathostomiasis and sparganosis are undoubtedly emerging zoonoses of particular medical interest. Prevention of these diseases relies on abstinence from eating raw meat from invertebrates or cold-blooded (poikilotherm) vertebrates (e.g. used in exotic dishes). These guidelines must be included in recommendations to travelers.

  20. Parasitism and calfhood diseases.

    PubMed

    Herlich, H; Douvres, F W

    1977-02-01

    That animals can and do acquire an effective immunity against helminth parasites has been demonstrated extensively experimentally, and the fact that domestic animals such as cattle, sheep, and horses become adults while maintaining good health in spite of constant exposure to reinfection long has suggested that immunity must be important to such survival. Although our attempts to date to vaccinate calves against helminth parasites have either failed or been unsatisfactory because of the pathosis induced by the experimental vaccines, the results are not surprising or discouraging. In contrast to the long history of immunization research on bacterial and viral diseases, only within a relatively short time have serious efforts been directed at exploiting hostal immunity for prevention and control of helminthic diseases. Unlike the comparatively simple structures of viruses and bacteria, helminths are complex multicellular animals with vast arrays of antigens and complicated physiological and immunological interactions with their hosts. Much more fundamental information on helminth-bovine interactions, on helminth antigens, and on cattle antibody systems must be developed before progress on control of cattle helminths by vaccination can be meaningful.

  1. Extracellular vesicles in parasitic diseases

    PubMed Central

    Marcilla, Antonio; Martin-Jaular, Lorena; Trelis, Maria; de Menezes-Neto, Armando; Osuna, Antonio; Bernal, Dolores; Fernandez-Becerra, Carmen; Almeida, Igor C.; del Portillo, Hernando A.

    2014-01-01

    Parasitic diseases affect billions of people and are considered a major public health issue. Close to 400 species are estimated to parasitize humans, of which around 90 are responsible for great clinical burden and mortality rates. Unfortunately, they are largely neglected as they are mainly endemic to poor regions. Of relevance to this review, there is accumulating evidence of the release of extracellular vesicles (EVs) in parasitic diseases, acting both in parasite–parasite inter-communication as well as in parasite–host interactions. EVs participate in the dissemination of the pathogen and play a role in the regulation of the host immune systems. Production of EVs from parasites or parasitized cells has been described for a number of parasitic infections. In this review, we provide the most relevant findings of the involvement of EVs in intercellular communication, modulation of immune responses, involvement in pathology, and their potential as new diagnostic tools and therapeutic agents in some of the major human parasitic pathogens. PMID:25536932

  2. Malaria, microscopic view of cellular parasites (image)

    MedlinePlus

    Malaria is a disease caused by parasites that are carried by mosquitoes. Once in the bloodstream, the parasite inhabits the red blood cell (RBC). This picture shows purple-stained malaria parasites inside red blood cells.

  3. Serine Proteases of Parasitic Helminths

    PubMed Central

    Yang, Yong; Wen, Yun jun; Cai, Ya Nan; Vallée, Isabelle; Boireau, Pascal; Liu, Ming Yuan; Cheng, Shi Peng

    2015-01-01

    Serine proteases form one of the most important families of enzymes and perform significant functions in a broad range of biological processes, such as intra- and extracellular protein metabolism, digestion, blood coagulation, regulation of development, and fertilization. A number of serine proteases have been identified in parasitic helminths that have putative roles in parasite development and nutrition, host tissues and cell invasion, anticoagulation, and immune evasion. In this review, we described the serine proteases that have been identified in parasitic helminths, including nematodes (Trichinella spiralis, T. pseudospiralis, Trichuris muris, Anisakis simplex, Ascaris suum, Onchocerca volvulus, O. lienalis, Brugia malayi, Ancylostoma caninum, and Steinernema carpocapsae), cestodes (Spirometra mansoni, Echinococcus granulosus, and Schistocephalus solidus), and trematodes (Fasciola hepatica, F. gigantica, and Schistosoma mansoni). Moreover, the possible biological functions of these serine proteases in the endogenous biological phenomena of these parasites and in the host-parasite interaction were also discussed. PMID:25748703

  4. Navigating parasite webs and parasite flow: emerging and re-emerging parasitic zoonoses of wildlife origin.

    PubMed

    Polley, Lydden

    2005-10-01

    Wildlife are now recognised as an important source of emerging human pathogens, including parasites. This paper discusses the linkages between wildlife, people, zoonotic parasites and the ecosystems in which they co-exist, revisits definitions for 'emerging' and 're-emerging', and lists zoonotic parasites that can be acquired from wildlife including, for some, estimates of the associated global human health burdens. The paper also introduces the concepts of 'parasite webs' and 'parasite flow', provides a context for parasites, relative to other infectious agents, as causes of emerging human disease, and discusses drivers of disease emergence and re-emergence, especially changes in biodiversity and climate. Angiostrongylus cantonensis in the Caribbean and the southern United States, Baylisascaris procyonis in California and Georgia, Plasmodium knowlesi in Sarawak, Malaysia, Human African Trypanosomiasis, Sarcoptes scabiei in carnivores, and Cryptosporidium, Giardia and Toxoplasma in marine ecosystems are presented as examples of wildlife-derived zoonotic parasites of particular recent interest. An ecological approach to disease is promoted, as is a need for an increased profile for this approach in undergraduate and graduate education in the health sciences. Synergy among scientists and disciplines is identified as critical for the study of parasites and parasitic disease in wildlife populations. Recent advances in techniques for the investigation of parasite fauna of wildlife are presented and monitoring and surveillance systems for wildlife disease are discussed. Some of the limitations inherent in predictions for the emergence and re-emergence of infection and disease associated with zoonotic parasites of wildlife are identified. The importance of public awareness and public education in the prevention and control of emerging and re-emerging zoonotic infection and disease are emphasised. Finally, some thoughts for the future are presented.

  5. 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.

  6. Parasites in algae mass culture

    PubMed Central

    Carney, Laura T.; Lane, Todd W.

    2014-01-01

    Parasites are now known to be ubiquitous across biological systems and can play an important role in modulating algal populations. However, there is a lack of extensive information on their role in artificial ecosystems such as algal production ponds and photobioreactors. Parasites have been implicated in the demise of algal blooms. Because individual mass culture systems often tend to be unialgal and a select few algal species are in wide scale application, there is an increased potential for parasites to have a devastating effect on commercial scale monoculture. As commercial algal production continues to expand with a widening variety of applications, including biofuel, food and pharmaceuticals, the parasites associated with algae will become of greater interest and potential economic impact. A number of important algal parasites have been identified in algal mass culture systems in the last few years and this number is sure to grow as the number of commercial algae ventures increases. Here, we review the research that has identified and characterized parasites infecting mass cultivated algae, the techniques being proposed and or developed to control them, and the potential impact of parasites on the future of the algal biomass industry. PMID:24936200

  7. 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

  8. Malaria parasite development in mosquitoes.

    PubMed

    Beier, J C

    1998-01-01

    Mosquitoes of the genus Anopheles transmit malaria parasites to humans. Anopheles mosquito species vary in their vector potential because of environmental conditions and factors affecting their abundance, blood-feeding behavior, survival, and ability to support malaria parasite development. In the complex life cycle of the parasite in female mosquitoes, a process termed sporogony, mosquitoes acquire gametocyte-stage parasites from blood-feeding on an infected host. The parasites carry out fertilization in the midgut, transform to ookinetes, then oocysts, which produce sporozoites. Sporozoites invade the salivary glands and are transmitted when the mosquito feeds on another host. Most individual mosquitoes that ingest gametocytes do not support development to the sporozoite stage. Bottle-necks occur at every stage of the cycle in the mosquito. Powerful new techniques and approaches exist for evaluating malaria parasite development and for identifying mechanisms regulating malaria parasite-vector interactions. This review focuses on those interactions that are important for the development of new approaches for evaluating and blocking transmission in nature.

  9. Congenital parasitic infections: a review.

    PubMed

    Carlier, Yves; Truyens, Carine; Deloron, Philippe; Peyron, François

    2012-02-01

    This review defines the concepts of maternal-fetal (congenital) and vertical transmissions (mother-to-child) of pathogens and specifies the human parasites susceptible to be congenitally transferred. It highlights the epidemiological features of this transmission mode for the three main congenital parasitic infections due to Toxoplasma gondii, Trypanosoma cruzi and Plasmodium sp. Information on the possible maternal-fetal routes of transmission, the placental responses to infection and timing of parasite transmission are synthesized and compared. The factors susceptible to be involved in parasite transmission and development of congenital parasitic diseases, such as the parasite genotypes, the maternal co-infections and parasitic load, the immunological features of pregnant women and the capacity of some fetuses/neonates to overcome their immunological immaturity to mount an immune response against the transmitted parasites are also discussed and compared. Analysis of clinical data indicates that parasitic congenital infections are often asymptomatic, whereas symptomatic newborns generally display non-specific symptoms. The long-term consequences of congenital infections are also mentioned, such as the imprinting of neonatal immune system and the possible trans-generational transmission. The detection of infection in pregnant women is mainly based on standard serological or parasitological investigations. Amniocentesis and cordocentesis can be used for the detection of some fetal infections. The neonatal infection can be assessed using parasitological, molecular or immunological methods; the place of PCR in such neonatal diagnosis is discussed. When such laboratory diagnosis is not possible at birth or in the first weeks of life, standard serological investigations can also be performed 8-10 months after birth, to avoid detection of maternal transmitted antibodies. The specific aspects of treatment of T. gondii, T. cruzi and Plasmodium congenital infections are

  10. Predictability of helminth parasite host range using information on geography, host traits and parasite community structure.

    PubMed

    Dallas, Tad; Park, Andrew W; Drake, John M

    2017-02-01

    Host-parasite associations are complex interactions dependent on aspects of hosts (e.g. traits, phylogeny or coevolutionary history), parasites (e.g. traits and parasite interactions) and geography (e.g. latitude). Predicting the permissive host set or the subset of the host community that a parasite can infect is a central goal of parasite ecology. Here we develop models that accurately predict the permissive host set of 562 helminth parasites in five different parasite taxonomic groups. We developed predictive models using host traits, host taxonomy, geographic covariates, and parasite community composition, finding that models trained on parasite community variables were more accurate than any other covariate group, even though parasite community covariates only captured a quarter of the variance in parasite community composition. This suggests that it is possible to predict the permissive host set for a given parasite, and that parasite community structure is an important predictor, potentially because parasite communities are interacting non-random assemblages.

  11. Glomerulopathy Associated with Parasitic Infections

    PubMed Central

    van Velthuysen, M.-L. F.; Florquin, S.

    2000-01-01

    Although parasitic infections do not usually present with disturbance in renal function, glomerular lesions can be seen in most of these infections. The glomerular lesions observed in parasitic infections cover the whole range of glomerular lesions known, but most of them are proliferative. Little is known of the exact pathogenic mechanisms. In this review, we try to explain the glomerular lesions associated with parasitic infections in terms of the specific immunologic events observed during these diseases against the background of recent developments in the general knowledge of the pathogenesis of glomerular disease. PMID:10627491

  12. Parasites as probes for biodiversity.

    PubMed

    Gardner, S L; Campbell, M L

    1992-08-01

    Cestodes of the genus Linstowia, parasitic in marsupials, show patterns of coevolution and ancient historical-ecological connections. Correlated with the breakup of the austral landmasses (Gondwanaland) of the Neotropical and Australian regions from the Antarctic continent, the age of this host-parasite community is estimated to be between 60 and 70 million years old. Based on the data from the survey of parasites of mammals from throughout Bolivia and from the phylogenetic analysis of the cestodes, we urge the planners of biodiversity preserves in the neotropics to consider the Yungas of Bolivia as a region that supports an ancient ecological community worthy of consideration as a biopreserve.

  13. Parasites in pet reptiles.

    PubMed

    Rataj, Aleksandra Vergles; Lindtner-Knific, Renata; Vlahović, Ksenija; Mavri, Urška; Dovč, Alenka

    2011-05-30

    Exotic reptiles originating from the wild can be carriers of many different pathogens and some of them can infect humans. Reptiles imported into Slovenia from 2000 to 2005, specimens of native species taken from the wild and captive bred species were investigated. A total of 949 reptiles (55 snakes, 331 lizards and 563 turtles), belonging to 68 different species, were examined for the presence of endoparasites and ectoparasites. Twelve different groups (Nematoda (5), Trematoda (1), Acanthocephala (1), Pentastomida (1) and Protozoa (4)) of endoparasites were determined in 26 (47.3%) of 55 examined snakes. In snakes two different species of ectoparasites were also found. Among the tested lizards eighteen different groups (Nematoda (8), Cestoda (1), Trematoda (1), Acanthocephala (1), Pentastomida (1) and Protozoa (6)) of endoparasites in 252 (76.1%) of 331 examined animals were found. One Trombiculid ectoparasite was determined. In 563 of examined turtles eight different groups (Nematoda (4), Cestoda (1), Trematoda (1) and Protozoa (2)) of endoparasites were determined in 498 (88.5%) animals. In examined turtles three different species of ectoparasites were seen. The established prevalence of various parasites in reptiles used as pet animals indicates the need for examination on specific pathogens prior to introduction to owners.

  14. Myxozoan parasitism in waterfowl.

    PubMed

    Bartholomew, Jerri L; Atkinson, Stephen D; Hallett, Sascha L; Lowenstine, Linda J; Garner, Michael M; Gardiner, Chris H; Rideout, Bruce A; Keel, M Kevin; Brown, Justin D

    2008-08-01

    Myxozoans are spore-forming, metazoan parasites common in cold-blooded aquatic vertebrates, especially fishes, with alternate life cycle stages developing in invertebrates. We report nine cases of infection in free-flying native and captive exotic ducks (Anseriformes: Anatidae) from locations across the United States and describe the first myxozoan in birds, Myxidium anatidum n. sp. We found developmental stages and mature spores in the bile ducts of a Pekin duck (domesticated Anas platyrhynchos). Spores are lens-shaped in sutural view, slightly sigmoidal in valvular view, with two polar capsules, and each valve cell has 14-16 longitudinal surface ridges. Spore dimensions are 23.1 microm x 10.8 microm x 11.2 microm. Phylogenetic analysis of the ssrRNA gene revealed closest affinity with Myxidium species described from chelonids (tortoises). Our novel finding broadens the definition of the Myxozoa to include birds as hosts and has implications for understanding myxozoan evolution, and mechanisms of geographical and host range extension. The number of infection records indicates this is not an incidental occurrence, and the detection of such widely dispersed cases suggests more myxozoans in birds will be encountered with increased surveillance of these hosts for pathogens.

  15. Synanthropic birds and parasites.

    PubMed

    Dipineto, Ludovico; Borrelli, Luca; Pepe, Paola; Fioretti, Alessandro; Caputo, Vincenzo; Cringoli, Giuseppe; Rinaldi, Laura

    2013-12-01

    This paper describes the parasitologic findings for 60 synanthropic bird carcasses recovered in the Campania region of southern Italy. Birds consisted of 20 yellow-legged gulls (Larus michahellis), 15 rock pigeons (Columba livia), 15 common kestrels (Falco tinnunculus), and 10 carrion crows (Corvus corone). Each carcass was examined to detect the presence of ectoparasites and then necropsied to detect helminths. Ectoparasites occurred in 100% of the birds examined. In particular, chewing lice were recovered with a prevalence of 100%, whereas Pseudolynchia canariensis (Hippoboscidae) were found only in pigeons with a prevalence of 80%. Regarding endoparasites, a total of seven helminth species were identified: three nematodes (Ascaridia columbae, Capillaria columbae, Physaloptera alata), one cestoda (Raillietina tetragona), one trematoda (Cardiocephalus longicollis), and two acanthocephalans (Centrorhynchus globocaudatus and Centrorhynchus buteonis). The findings of the present study add data to the parasitologic scenario of synanthropic birds. This is important because parasitic infection can lead to serious health problems when combined with other factors and may affect flying performance and predatory effectiveness.

  16. Parasites in pet reptiles

    PubMed Central

    2011-01-01

    Exotic reptiles originating from the wild can be carriers of many different pathogens and some of them can infect humans. Reptiles imported into Slovenia from 2000 to 2005, specimens of native species taken from the wild and captive bred species were investigated. A total of 949 reptiles (55 snakes, 331 lizards and 563 turtles), belonging to 68 different species, were examined for the presence of endoparasites and ectoparasites. Twelve different groups (Nematoda (5), Trematoda (1), Acanthocephala (1), Pentastomida (1) and Protozoa (4)) of endoparasites were determined in 26 (47.3%) of 55 examined snakes. In snakes two different species of ectoparasites were also found. Among the tested lizards eighteen different groups (Nematoda (8), Cestoda (1), Trematoda (1), Acanthocephala (1), Pentastomida (1) and Protozoa (6)) of endoparasites in 252 (76.1%) of 331 examined animals were found. One Trombiculid ectoparasite was determined. In 563 of examined turtles eight different groups (Nematoda (4), Cestoda (1), Trematoda (1) and Protozoa (2)) of endoparasites were determined in 498 (88.5%) animals. In examined turtles three different species of ectoparasites were seen. The established prevalence of various parasites in reptiles used as pet animals indicates the need for examination on specific pathogens prior to introduction to owners. PMID:21624124

  17. Zoology: Invertebrates that Parasitize Invertebrates.

    PubMed

    Giribet, Gonzalo

    2016-07-11

    The genome of an orthonectid, a group of highly modified parasitic invertebrates, is drastically reduced and compact, yet it shows the bilaterian gene toolkit. Phylogenetic analyses place the enigmatic orthonectids within Spiralia, although their exact placement remains uncertain.

  18. Tropical parasitic diseases and women.

    PubMed

    Okwa, O O

    2007-12-01

    Tropical parasitic diseases constitute the greatest threat to the health and socio-economic status of women as a gender and social group. There are some gender specific ways in which parasitic diseases affect women in contrast to men due to differences in exposure, occupational risk, sociocultural behavior, gender roles and practices. These parasitic diseases confer some social stigma, which affects the health seeking behavior of women. Women are therefore important in the control of these parasitic diseases and they are key agents of change, if they are included in community control programs. Women need more attention in endemic areas as a group that had been neglected. This deprived and excluded group have got vital role to play, as discussed in this review.

  19. Pregnancy, nutrition and parasitic diseases.

    PubMed

    Steketee, Richard W

    2003-05-01

    In the developing world, young women, pregnant women, and their infants and children frequently experience a cycle where undernutrition (macronutrient and micronutrient) and repeated infection, including parasitic infections, lead to adverse consequences that can continue from one generation to the next. Among parasitic infections, malaria and intestinal helminths coexist widely with micronutrient deficiencies and contribute importantly to anemia and this cycle of retarded growth and development. In somewhat more limited or focal geographic settings, other parasitic diseases (e.g., schistosomiasis, filariasis) contribute similarly to this cycle. It is undoubtedly much better to enter a pregnancy free of infection and nutritionally replete than the various alternatives. Existing intervention strategies for micronutrient support and for the control of common parasitic infections before or during pregnancy, particularly malaria and intestinal helminths, should be followed. However, further research to identify barriers and priority approaches to achieving this goal remain very important in resource-poor settings where targeted public health efforts are required.

  20. Atypical parasitic ischiopagus conjoined twins.

    PubMed

    Corona-Rivera, J Román; Corona-Rivera, Enrique; Franco-Topete, Ramón; Acosta-León, Jorge; Aguila-Dueñas, Virginia; Corona-Rivera, Alfredo

    2003-02-01

    Occurrence of asymmetrical or parasitic conjoined twins (CT) is rare, and currently they are classified analogically to the common unions of symmetrical CT. The authors report on an infant with a parasitic third limb attached to the left lateral aspect of the autosite trunk, in whom male gonadal tissue was found histologically. Parasite parts included complete left lower limb, hemipelvis, lumbosacral vertebral column, spinal cord, and one kidney with ureter and adrenal gland. Autosite anomalies comprised a small left diaphragmatic defect, omphalocele, exstrophy of cloaca, and lumbar meningomyelocele. The authors considered this case to be a rare atypical parasitic ischiopagus CT. The differential diagnosis of the type of twining and other entities with caudal duplications is analyzed briefly.

  1. Parasites and altruism: converging roads.

    PubMed

    Zuk, Marlene; Borrello, Mark E

    2013-01-01

    W.D. Hamilton was most known for his work on two topics: social evolution and parasites. Although at first glance these seem to be disparate interests, they share many attributes and have logical connections within evolutionary biology. Nevertheless, Hamilton's contributions in these areas met with very different receptions, with his place in the field of social evolution assured, but his work on the role of parasites perceived as more specialized. We take an historical approach to examine the reasons for this difference.

  2. Molecular diagnostics and parasitic disease.

    PubMed

    Vasoo, Shawn; Pritt, Bobbi S

    2013-09-01

    Molecular parasitology represents an emerging field in microbiology diagnostics. Although most assays use nonstandardized, laboratory-developed methods, a few commercial systems have recently become available and are slowly being introduced into larger laboratories. In addition, a few methodologies show promise for use in field settings in which parasitic infections are endemic. This article reviews the available techniques and their applications to major parasitic diseases such as malaria, leishmaniasis, and trichomoniasis.

  3. Pervasiveness of Parasites in Pollinators

    PubMed Central

    Evison, Sophie E. F.; Roberts, Katherine E.; Laurenson, Lynn; Pietravalle, Stéphane; Hui, Jeffrey; Biesmeijer, Jacobus C.; Smith, Judith E.; Budge, Giles; Hughes, William O. H.

    2012-01-01

    Many pollinator populations are declining, with large economic and ecological implications. Parasites are known to be an important factor in the some of the population declines of honey bees and bumblebees, but little is known about the parasites afflicting most other pollinators, or the extent of interspecific transmission or vectoring of parasites. Here we carry out a preliminary screening of pollinators (honey bees, five species of bumblebee, three species of wasp, four species of hoverfly and three genera of other bees) in the UK for parasites. We used molecular methods to screen for six honey bee viruses, Ascosphaera fungi, Microsporidia, and Wolbachia intracellular bacteria. We aimed simply to detect the presence of the parasites, encompassing vectoring as well as actual infections. Many pollinators of all types were positive for Ascosphaera fungi, while Microsporidia were rarer, being most frequently found in bumblebees. We also detected that most pollinators were positive for Wolbachia, most probably indicating infection with this intracellular symbiont, and raising the possibility that it may be an important factor in influencing host sex ratios or fitness in a diversity of pollinators. Importantly, we found that about a third of bumblebees (Bombus pascuorum and Bombus terrestris) and a third of wasps (Vespula vulgaris), as well as all honey bees, were positive for deformed wing virus, but that this virus was not present in other pollinators. Deformed wing virus therefore does not appear to be a general parasite of pollinators, but does interact significantly with at least three species of bumblebee and wasp. Further work is needed to establish the identity of some of the parasites, their spatiotemporal variation, and whether they are infecting the various pollinator species or being vectored. However, these results provide a first insight into the diversity, and potential exchange, of parasites in pollinator communities. PMID:22347356

  4. Pervasiveness of parasites in pollinators.

    PubMed

    Evison, Sophie E F; Roberts, Katherine E; Laurenson, Lynn; Pietravalle, Stéphane; Hui, Jeffrey; Biesmeijer, Jacobus C; Smith, Judith E; Budge, Giles; Hughes, William O H

    2012-01-01

    Many pollinator populations are declining, with large economic and ecological implications. Parasites are known to be an important factor in the some of the population declines of honey bees and bumblebees, but little is known about the parasites afflicting most other pollinators, or the extent of interspecific transmission or vectoring of parasites. Here we carry out a preliminary screening of pollinators (honey bees, five species of bumblebee, three species of wasp, four species of hoverfly and three genera of other bees) in the UK for parasites. We used molecular methods to screen for six honey bee viruses, Ascosphaera fungi, Microsporidia, and Wolbachia intracellular bacteria. We aimed simply to detect the presence of the parasites, encompassing vectoring as well as actual infections. Many pollinators of all types were positive for Ascosphaera fungi, while Microsporidia were rarer, being most frequently found in bumblebees. We also detected that most pollinators were positive for Wolbachia, most probably indicating infection with this intracellular symbiont, and raising the possibility that it may be an important factor in influencing host sex ratios or fitness in a diversity of pollinators. Importantly, we found that about a third of bumblebees (Bombus pascuorum and Bombus terrestris) and a third of wasps (Vespula vulgaris), as well as all honey bees, were positive for deformed wing virus, but that this virus was not present in other pollinators. Deformed wing virus therefore does not appear to be a general parasite of pollinators, but does interact significantly with at least three species of bumblebee and wasp. Further work is needed to establish the identity of some of the parasites, their spatiotemporal variation, and whether they are infecting the various pollinator species or being vectored. However, these results provide a first insight into the diversity, and potential exchange, of parasites in pollinator communities.

  5. [Water and intestinal parasitic diseases].

    PubMed

    Romanenko, N A; Belova, E G; Baburina, L V; Novosil'tsev, G I; Chernyshenko, A I

    2004-01-01

    The paper presents data on the rates of Lamblia cyst dissemination of surface water sources in foreign countries, the Russian Federation, Moscow, and the Moscow Region. It shows a role of drinking water in the spread of intestinal parasitic diseases. In accordance with parasitological parameters, specific data on improvement of methodological control of water quality are presented. The dosages of ultraviolet radiation are given in relation to water decontamination of parasitic disease germs.

  6. Microsatellite analysis of malaria parasites.

    PubMed

    Orjuela-Sánchez, Pamela; Brandi, Michelle C; Ferreira, Marcelo U

    2013-01-01

    Microsatellites have been increasingly used to investigate the population structure of malaria parasites, to map genetic loci contributing to phenotypes such as drug resistance and virulence in laboratory crosses and genome-wide association studies and to distinguish between treatment failures and new infections in clinical trials. Here, we provide optimized protocols for genotyping highly polymorphic microsatellites sampled from across the genomes of the human malaria parasites Plasmodium falciparum and P. vivax that have been extensively used in research laboratories worldwide.

  7. Parasitic Effects on Memristor Dynamics

    NASA Astrophysics Data System (ADS)

    Itoh, Makoto; Chua, Leon O.

    2016-06-01

    In this paper, we show that parasitic elements have a significant effect on the dynamics of memristor circuits. We first show that certain 2-terminal elements such as memristors, memcapacitors, and meminductors can be used as nonvolatile memories, if the principle of conservation of state variables hold by open-circuiting, or short-circuiting, their terminals. We also show that a passive memristor with a strictly-increasing constitutive relation will eventually lose its stored flux when we switch off the power if there is a parasitic capacitance across the memristor. Similarly, a memcapacitor (resp., meminductor) with a positive memcapacitance (resp., meminductance) will eventually lose their stored physical states when we switch off the power, if it is connected to a parasitic resistance. We then show that the discontinuous jump that circuit engineers assumed to occur at impasse points of memristor circuits contradicts the principles of conservation of charge and flux at the time of the discontinuous jump. A parasitic element can be used to break an impasse point, resulting in the emergence of a continuous oscillation in the circuit. We also define a distance, a diameter, and a dimension, for each circuit element in order to measure the complexity order of the parasitic elements. They can be used to find higher-order parasitic elements which can break impasse points. Furthermore, we derived a memristor-based Chua’s circuit from a three-element circuit containing a memristor by connecting two parasitic memcapacitances to break the impasse points. We finally show that a higher-order parasitic element can be used for breaking the impasse points on two-dimensional and three-dimensional constrained spaces.

  8. Evolution: Causality and the Origin of Parasitism.

    PubMed

    Janouskovec, Jan; Keeling, Patrick J

    2016-02-22

    The first comparison of parasitic trypanosomatids to their free-living relatives reveals that some characteristics once linked to parasitism actually predate it. Parallel comparisons of other parasites suggest we need to rethink the drivers and consequences of the parasitic lifestyle.

  9. Parasitic Pneumonia and Lung Involvement

    PubMed Central

    Cheepsattayakorn, Ruangrong

    2014-01-01

    Parasitic infestations demonstrated a decline in the past decade as a result of better hygiene practices and improved socioeconomic conditions. Nevertheless, global immigration, increased numbers of the immunocompromised people, international traveling, global warming, and rapid urbanization of the cities have increased the susceptibility of the world population to parasitic diseases. A number of new human parasites, such as Plasmodium knowlesi, in addition to many potential parasites, have urged the interest of scientific community. A broad spectrum of protozoal parasites frequently affects the respiratory system, particularly the lungs. The diagnosis of parasitic diseases of airway is challenging due to their wide varieties of clinical and roentgenographic presentations. So detailed interrogations of travel history to endemic areas are critical for clinicians or pulmonologists to manage this entity. The migrating adult worms can cause mechanical airway obstruction, while the larvae can cause airway inflammation. This paper provides a comprehensive review of both protozoal and helminthic infestations that affect the airway system, particularly the lungs, including clinical and roentgenographic presentations, diagnostic tests, and therapeutic approaches. PMID:24995332

  10. Birds are islands for parasites.

    PubMed

    Koop, Jennifer A H; DeMatteo, Karen E; Parker, Patricia G; Whiteman, Noah K

    2014-08-01

    Understanding the mechanisms driving the extraordinary diversification of parasites is a major challenge in evolutionary biology. Co-speciation, one proposed mechanism that could contribute to this diversity is hypothesized to result from allopatric co-divergence of host-parasite populations. We found that island populations of the Galápagos hawk (Buteo galapagoensis) and a parasitic feather louse species (Degeeriella regalis) exhibit patterns of co-divergence across variable temporal and spatial scales. Hawks and lice showed nearly identical population genetic structure across the Galápagos Islands. Hawk population genetic structure is explained by isolation by distance among islands. Louse population structure is best explained by hawk population structure, rather than isolation by distance per se, suggesting that lice tightly track the recent population histories of their hosts. Among hawk individuals, louse populations were also highly structured, suggesting that hosts serve as islands for parasites from an evolutionary perspective. Altogether, we found that host and parasite populations may have responded in the same manner to geographical isolation across spatial scales. Allopatric co-divergence is likely one important mechanism driving the diversification of parasites.

  11. Lipids and the malarial parasite*

    PubMed Central

    Holz, George G.

    1977-01-01

    Merozoite endocytosis initiates Plasmodium development in a vacuole bounded by an erythrocyte-derived membrane, whose asymmetrical distribution of lipids and proteins is reversed in its orientation with respect to the parasite plasma membrane. Reorientation may accompany the proliferation of the membrane associated with the parasite's growth and phagocytic and pinocytic feeding. Increases in the membrane surface area of the parasite, and in some cases of the erythrocyte, parallel parasite growth and segmentation. Augmentation of all the membrane systems of the infected erythrocyte causes the lipid content to rise rapidly, but the parasite lipid composition differs from that of the erythrocyte in many respects: it is higher in diacyl phosphatidylethanolamine, phosphatidylinositol, polyglycerol phosphatides, diacylglycerols, unesterified fatty acids, triacylglycerols, and hexadecanoic and octadecenoic fatty acids and lower in sphingomyelin, phosphatidylserine, alkoxy phosphatidylethanolamine, cholesterol, and polyunsaturated fatty acids. Active lipid metabolism accompanies the membrane proliferation associated with feeding, growth, and reproduction. Plasmodium is incapable of de novo biosynthesis of fatty acids and cholesterol; however, it can fabricate its glycerides and phosphoglycerides with host-supplied fatty acids, nitrogenous bases, alcohols, ATP, and coenzyme A, and can generate the glyceryl moiety during glycolysis. Cholesterol is obtained from the host but nothing is known of sphingolipid origins. Lipid metabolism of the parasite may be associated with alterations in the amounts of octadecenoic fatty acids and cholesterol in the erythrocyte plasma membrane, which in turn are responsible for changes in permeability and fragility. PMID:412602

  12. Paleoparasitology: the origin of human parasites.

    PubMed

    Araújo, Adauto; Reinhard, Karl; Ferreira, Luiz Fernando; Pucu, Elisa; Chieffi, Pedro Paulo

    2013-09-01

    Parasitism is composed by three subsystems: the parasite, the host, and the environment. There are no organisms that cannot be parasitized. The relationship between a parasite and its host species most of the time do not result in damage or disease to the host. However, in a parasitic disease the presence of a given parasite is always necessary, at least in a given moment of the infection. Some parasite species that infect humans were inherited from pre-hominids, and were shared with other phylogenetically close host species, but other parasite species were acquired from the environment as humans evolved. Human migration spread inherited parasites throughout the globe. To recover and trace the origin and evolution of infectious diseases, paleoparasitology was created. Paleoparasitology is the study of parasites in ancient material, which provided new information on the evolution, paleoepidemiology, ecology and phylogenetics of infectious diseases.

  13. Hosts and parasites as aliens.

    PubMed

    Taraschewski, H

    2006-06-01

    Over the past decades, various free-living animals (hosts) and their parasites have invaded recipient areas in which they had not previously occurred, thus gaining the status of aliens or exotics. In general this happened to a low extent for hundreds of years. With variable frequency, invasions have been followed by the dispersal and establishment of non-indigenous species, whether host or parasite. In the literature thus far, colonizations by both hosts and parasites have not been treated and reviewed together, although both are usually interwoven in various ways. As to those factors permitting invasive success and colonization strength, various hypotheses have been put forward depending on the scientific background of respective authors and on the conspicuousness of certain invasions. Researchers who have tried to analyse characteristic developmental patterns, the speed of dispersal or the degree of genetic divergence in populations of alien species have come to different conclusions. Among parasitologists, the applied aspects of parasite invasions, such as the negative effects on economically important hosts, have long been at the centre of interest. In this contribution, invasions by hosts as well as parasites are considered comparatively, revealing many similarities and a few differences. Two helminths, the liver fluke, Fasciola hepatica, of cattle and sheep and the swimbladder nematode, Anguillicola crassus, of eels are shown to be useful as model parasites for the study of animal invasions and environmental global change. Introductions of F. hepatica have been associated with imports of cattle or other grazing animals. In various target areas, susceptible lymnaeid snails serving as intermediate hosts were either naturally present and/or were introduced from the donor continent of the parasite (Europe) and/or from other regions which were not within the original range of the parasite, partly reflecting progressive stages of a global biota change. In several

  14. 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.

  15. Parasitic polymorphism of Coccidioides spp

    PubMed Central

    2014-01-01

    Background Coccidioides spp. is the ethiological agent of coccidioidomycosis, an infection that can be fatal. Its diagnosis is complicated, due to that it shares clinical and histopathological characteristics with other pulmonary mycoses. Coccidioides spp. is a dimorphic fungus and, in its saprobic phase, grows as a mycelium, forming a large amount of arthroconidia. In susceptible persons, arthroconidia induce dimorphic changes into spherules/endospores, a typical parasitic form of Coccidioides spp. In addition, the diversity of mycelial parasitic forms has been observed in clinical specimens; they are scarcely known and produce errors in diagnosis. Methods We presented a retrospective study of images from specimens of smears with 15% potassium hydroxide, cytology, and tissue biopsies of a histopathologic collection from patients with coccidioidomycosis seen at a tertiary-care hospital in Mexico City. Results The parasitic polymorphism of Coccidioides spp. observed in the clinical specimens was as follows: i) spherules/endospores in different maturation stages; ii) pleomorphic cells (septate hyphae, hyphae composed of ovoid and spherical cells, and arthroconidia), and iii) fungal ball formation (mycelia with septate hyphae and arthroconidia). Conclusions The parasitic polymorphism of Coccidioides spp. includes the following: spherules/endospores, arthroconidia, and different forms of mycelia. This knowledge is important for the accurate diagnosis of coccidioidomycosis. In earlier studies, we proposed the integration of this diversity of forms in the Coccidioides spp. parasitic cycle. The microhabitat surrounding the fungus into the host would favor the parasitic polymorphism of this fungus, and this environment may assist in the evolution toward parasitism of Coccidioides spp. PMID:24750998

  16. Parasites, pets, and people.

    PubMed

    Marx, M B

    1991-03-01

    It is important for the family physician to understand that patients' relationships with their pets play an important role in helping maintain mental and physical health yet provide the potential for causing illness in the patient. Toxocara canis (dog roundworm) and Toxocara cati (cat roundworm) are the ascarids most commonly responsible for VLM and ocular larva migrans in humans. These roundworms live in their adult stage in the small intestine of the dog and cat where their eggs are passed in the feces. The eggs containing the infective larva are very sticky, thus an infant crawling around on the floor can easily pick these up on fingers that almost invariably end up in the mouth. Infections are usually mild and asymptomatic but with a persistent eosinophilia. Ocular larva migrans is the form usually occurring in older children and adults. Some public health veterinarians recommend that a puppy or kitten should not be obtained as a companion for a child who is not old enough to read, thus bypassing the crawling and toddler stages. Hookworm eggs, shed in the feces of infected dogs or cats, develop into the infective second stage within a week. Humans are usually infected when bare areas of skin such as bare feet or the torso come in contact with soil contaminated with the larvae. The second-stage larvae are able to penetrate the intact skin of humans and the foot pads of dogs and cats. In the United States, the common dog hookworm, A. caninum, is a widespread parasite. Human intestinal ancylostomiasis caused by this species is rare, with only six cases recorded in the literature. Infection in humans or animals by the common tapeworm of dogs and cats (Dipylidium caninum) requires ingestion of the intermediate host, the dog or cat flea containing the larva (cysticercoids) of the agent. Many cases in humans are asymptomatic. Dipylidiasis affects mainly infants and young children who may swallow a flea that hops up while the infant is crawling on the floor or fondling

  17. Leptin, a tool of parasites?

    PubMed Central

    Lõhmus, Mare; Moalem, Sharon; Björklund, Mats

    2012-01-01

    One common physiological phenomenon that is involved both in infectious and in malignant processes is the reduction in appetite: disease anorexia. An increase in plasma levels of leptin with inflammation is thought to be involved in this process. However, from an evolutionary perspective, in certain cases, it would be more adaptive for an internal parasite to stimulate the appetite of the host instead of causing its suppression. We tested whether a parasitic infection with the larvae of the helminth parasite Taenia taeniaformis affects the levels of appetite-regulating proteins, such as leptin, ghrelin and neuropeptide-Y (NPY) in wild yellow-necked mouse (Apodemus flavicollis). We found that infected mice had lower plasma levels of leptin and increased levels of NPY than the uninfected subjects. Ghrelin levels were not associated with the occurrence of the parasites; however, these levels strongly correlated with the levels of NPY. This study suggests a possible manipulation by parasitic larvae of appetite regulation in infected subjects. PMID:22740641

  18. Host-parasite interactions: Marine bivalve molluscs and protozoan parasites, Perkinsus species.

    PubMed

    Soudant, Philippe; E Chu, Fu-Lin; Volety, Aswani

    2013-10-01

    This review assesses and examines the work conducted to date concerning host and parasite interactions between marine bivalve molluscs and protozoan parasites, belonging to Perkinsus species. The review focuses on two well-studied host-parasite interaction models: the two clam species, Ruditapes philippinarum and R. decussatus, and the parasite Perkinsus olseni, and the eastern oyster, Crassostrea virginica, and the parasite Perkinsus marinus. Cellular and humoral defense responses of the host in combating parasitic infection, the mechanisms (e.g., antioxidant enzymes, extracellular products) employed by the parasite in evading host defenses as well as the role of environmental factors in modulating the host-parasite interactions are described.

  19. Parasitic diseases of the pleura.

    PubMed

    Lal, Chitra; Huggins, John Terrill; Sahn, Steven A

    2013-05-01

    Parasitic infections are prevalent in certain parts of the world and may cause pleural involvement, which often goes unrecognized. Common parasites involving the pleura include Entamoeba histolytica, Echinococcus granulosus and Paragonimus westermani. Amebiasis can cause empyema with "anchovy sauce" pus, reactive pleural effusions and bronchopleural fistula with hydropneumothorax. Echinococcosis may result in pleural thickening, pneumothorax, secondary pleural hydatidosis and pleural effusions. Paragonimiasis may cause chylous and cholesterol pleural effusions, pleural thickening and pneumothorax. Less commonly, pulmonary eosinophilia, or Loeffler's syndrome, caused by Ascaris lumbricoides, Ancylostoma duodenale and Necator americanus and tropical pulmonary eosinophilia caused by Wuchereria bancrofti and Brugia malayi may involve the pleura. This article provides a comprehensive review of parasitic infections involving the pleura. A high index of suspicion in the appropriate clinical setting is required to facilitate prompt diagnosis and treatment of these diseases.

  20. Isoprenoid metabolism in apicomplexan parasites

    PubMed Central

    Imlay, Leah; Odom, Audrey R.

    2014-01-01

    Apicomplexan parasites include some of the most prevalent and deadly human pathogens. Novel antiparasitic drugs are urgently needed. Synthesis and metabolism of isoprenoids may present multiple targets for therapeutic intervention. The apicoplast-localized methylerythritol phosphate (MEP) pathway for isoprenoid precursor biosynthesis is distinct from the mevalonate (MVA) pathway used by the mammalian host, and this pathway is apparently essential in most Apicomplexa. In this review, we discuss the current field of research on production and metabolic fates of isoprenoids in apicomplexan parasites, including the acquisition of host isoprenoid precursors and downstream products. We describe recent work identifying the first MEP pathway regulator in apicomplexan parasites, and introduce several promising areas for ongoing research into this well-validated antiparasitic target. PMID:25893156

  1. Parasites, emerging disease and wildlife conservation.

    PubMed

    Thompson, R C A; Lymbery, A J; Smith, A

    2010-08-15

    In this review some emerging issues of parasite infections in wildlife, particularly in Australia, are considered. We discuss the importance of understanding parasite biodiversity in wildlife in terms of conservation, the role of wildlife as reservoirs of parasite infection, and the role of parasites within the broader context of the ecosystem. Using a number of parasite species, the value of undertaking longitudinal surveillance in natural systems using non-invasive sampling and molecular tools to characterise infectious agents is illustrated in terms of wildlife health, parasite biodiversity and ecology.

  2. Parasitic Diseases - Multiple Languages: MedlinePlus

    MedlinePlus

    ... Are Here: Home → Multiple Languages → All Health Topics → Parasitic Diseases URL of this page: https://medlineplus.gov/languages/ ... V W XYZ List of All Topics All Parasitic Diseases - Multiple Languages To use the sharing features on ...

  3. Malaria, photomicrograph of cellular parasites (image)

    MedlinePlus

    Malaria is a disease caused by parasites. This picture shows dark orange-stained malaria parasites inside red blood cells (a) and outside the cells (b). Note the large cells that look like targets; ...

  4. Can Parasites Really Reveal Environmental Impact?

    EPA Science Inventory

    This review assesses the usefulness of parasites as bioindicators of environmental impact. Relevant studies published in the past decade were compiled; factorial meta-analysis demonstrated significant effects and interactions between parasite levels and the presence and concentra...

  5. Biology Today: Parasites and Human Ecology.

    ERIC Educational Resources Information Center

    Flannery, Maura C.

    1984-01-01

    Offers various reasons why the study of parasites and the diseases they cause should be incorporated into classroom biology discussions. Examples of several parasitic diseases and their ecological significance are provided. (JN)

  6. Antimicrobial peptide action on parasites.

    PubMed

    Torrent, Marc; Pulido, David; Rivas, Luis; Andreu, David

    2012-08-01

    Diseases caused by protozoan parasites can pose a severe thread to human health and are behind some serious neglected tropical diseases like malaria and leishmaniasis. Though several different drugs have been developed in order to eradicate these diseases, a successful candidate has not yet been discovered. Among the most active compounds tested, antimicrobial peptides (AMPs) are particularly appealing because of their wide spectrum of action. AMPs have been described to perturb protozoan homeostasis by disrupting the cellular membranes but also by interfering with key processes in the parasite metabolism. In this review we describe the diverse mechanisms of action of AMPs on protozoan targets and how they can be exploited to treat diseases. Moreover, we describe with detail the antimicrobial action of AMPs on two major parasitical infections: leishmaniasis and malaria. All the features reviewed here show that AMPs are promising drugs to target protozoan parasites and that further understanding of the mechanism of action of these compounds will lead to improved drugs that could be worth to test in a clinical phase.

  7. An ABA-responsive DRE-binding protein gene from Setaria italica, SiARDP, the target gene of SiAREB, plays a critical role under drought stress.

    PubMed

    Li, Cong; Yue, Jing; Wu, Xiaowei; Xu, Cong; Yu, Jingjuan

    2014-10-01

    The DREB (dehydration-responsive element binding)-type transcription factors regulate the expression of stress-inducible genes by binding the DRE/CRT cis-elements in promoter regions. The upstream transcription factors that regulate the transcription of DREB transcription factors have not been clearly defined, although the function of DREB transcription factors in abiotic stress is known. In this study, an abscisic acid (ABA)-responsive DREB-binding protein gene (SiARDP) was cloned from foxtail millet (Setaria italica). The transcript level of SiARDP increased not only after drought, high salt, and low temperature stresses, but also after an ABA treatment in foxtail millet seedlings. Two ABA-responsive elements (ABRE1: ACGTGTC; ABRE2: ACGTGGC) exist in the promoter of SiARDP. Further analyses showed that two ABA-responsive element binding (AREB)-type transcription factors, SiAREB1 and SiAREB2, could physically bind to the ABRE core element in vitro and in vivo. The constitutive expression of SiARDP in Arabidopsis thaliana enhanced drought and salt tolerance during seed germination and seedling development, and overexpression of SiARDP in foxtail millet improved drought tolerance. The expression levels of target genes of SiARDP were upregulated in transgenic Arabidopsis and foxtail millet. These results reveal that SiARDP, one of the target genes of SiAREB, is involved in ABA-dependent signal pathways and plays a critical role in the abiotic stress response in plants.

  8. Extraction and characterization of microcrystalline cellulose from fodder grass; Setaria glauca (L) P. Beauv, and its potential as a drug delivery vehicle for isoniazid, a first line antituberculosis drug.

    PubMed

    Kalita, Ranjan Dutta; Nath, Yutika; Ochubiojo, Martins E; Buragohain, Alak Kumar

    2013-08-01

    Microcrystalline cellulose (MCC) is generally produced through acid hydrolysis of woody plants and agro sources. MCC synthesized from a common wild grass Setaria glauca (L) P. Beauv was characterized to explore the possibility of application in pharmaceutical industry especially as a drug delivery vehicle. The SEM, TGA, XRD and FTIR investigations of the prepared MCC reveal that the 5-30μm long, non aggregated MCC rods have high crystallinity index of 80% and were stable at 286°C. The preliminary investigation of the MCC incorporated micro beads containing isoniazid, one of the first line drugs for treatment of tuberculosis was carried out in the simulated intestinal fluid (SIF). The MCC incorporated micro beads with isoniazid drug load showed sustained release upto 24h with release of 0.521μg of isoniazid equivalent drug in the SIF system. No cytotoxicity of the MCC was observed in the haemolytic assay. The MCC also showed good antioxidant activity. Thus, the study reveals that the MCC can be prepared from an inexpensive and abundant grass species. The MCC have properties advantageous for application in the pharmaceutical industry and may be explored further in drug delivery research.

  9. Emerging parasitic diseases of sheep.

    PubMed

    Taylor, M A

    2012-09-30

    There have been changes in the emergence and inability to control of a number of sheep parasitic infections over the last decade. This review focuses on the more globally important sheep parasites, whose reported changes in epidemiology, occurrence or failure to control are becoming increasingly evident. One of the main perceived driving forces is climate change, which can have profound effects on parasite epidemiology, especially for those parasitic diseases where weather has a direct effect on the development of free-living stages. The emergence of anthelmintic-resistant strains of parasitic nematodes and the increasing reliance placed on anthelmintics for their control, can exert profound changes on the epidemiology of those nematodes causing parasitic gastroenteritis. As a consequence, the effectiveness of existing control strategies presents a major threat to sheep production in many areas around the world. The incidence of the liver fluke, Fasciola hepatica, is inextricably linked to high rainfall and is particularly prevalent in high rainfall years. Over the last few decades, there have also been increasing reports of other fluke associated diseases, such as dicroceliosis and paramphistomosis, in a number of western European countries, possibly introduced through animal movements, and able to establish with changing climates. External parasite infections, such as myiasis, can cause significant economic loss and presents as a major welfare problem. The range of elevated temperatures predicted by current climate change scenarios, result in an elongated blowfly season with earlier spring emergence and a higher cumulative incidence of fly strike. Additionally, legislative decisions leading to enforced changes in pesticide usage and choices have resulted in increased reports and spread of ectoparasitic infections, particularly mite, lice and tick infestations in sheep. Factors, such as dip disposal and associated environmental concerns, and, perhaps more

  10. One Health: parasites and beyond.

    PubMed

    Blake, Damer P; Betson, Martha

    2017-01-01

    The field of parasitism is broad, encompassing relationships between organisms where one benefits at the expense of another. Traditionally the discipline focuses on eukaryotes, with the study of bacteria and viruses complementary but distinct. Nonetheless, parasites vary in size and complexity from single celled protozoa, to enormous plants like those in the genus Rafflesia. Lifecycles range from obligate intracellular to extensive exoparasitism. Examples of parasites include high-profile medical and zoonotic pathogens such as Plasmodium, veterinary pathogens of wild and captive animals and many of the agents which cause neglected tropical diseases, stretching to parasites which infect plants and other parasites (e.g. Kikuchi et al. 2011; Hotez et al. 2014; Blake et al. 2015; Hemingway, 2015; Meekums et al. 2015; Sandlund et al. 2015). The breadth of parasitology has been matched by the variety of ways in which parasites are studied, drawing upon biological, chemical, molecular, epidemiological and other expertise. Despite such breadth bridging between disciplines has commonly been problematic, regardless of extensive encouragement from government agencies, peer audiences and funding bodies promoting multidisciplinary research. Now, progress in understanding and collaboration can benefit from establishment of the One Health concept (Zinsstag et al. 2012; Stark et al. 2015). One Health draws upon biological, environmental, medical, veterinary and social science disciplines in order to improve human, animal and environmental health, although it remains tantalizingly difficult to engage many relevant parties. For infectious diseases traditional divides have been exacerbated as the importance of wildlife reservoirs, climate change, food production systems and socio-economic diversity have been recognized but often not addressed in a multidisciplinary manner. In response the 2015 Autumn Symposium organized by the British Society for Parasitology (BSP; https

  11. Parasite control in transhumant situations.

    PubMed

    Eckert, J; Hertzberg, H

    1994-08-01

    Transhumance is defined as 'seasonal moving of livestock to regions of different climate'. It is an integral part of livestock production in many parts of the world and takes several forms including moving of livestock from lowland to mountainous pastures or from dry to humid areas. The impact of transhumance on parasite populations of livestock and on parasite control is described, mainly using examples from Europe. The epidemiology of trichostrongylidosis of cattle, mainly caused by Ostertagia ostertagi and Cooperia oncophora, is characterised by prolonged survival of overwintered infective larvae until the end of June. Cattle moved to such contaminated pastures in a transhumant grazing system are exposed to these larvae and may be protected, during the second half of the grazing season until autumn, by a late application (June/July) of an intraruminal drug-release device. Community pastures used in a transhumant system with mixed grazing of young cattle originating from various farms may enhance transmission of dictyocaulosis. Therefore, specific prophylactic measures are required. Hill sheep nematode populations may differ from those in lowland sheep in that Haemonchus contortus generally plays a minor role in hill sheep in which Ostertagia circumcincta and Nematodirus spp. predominate. Infections with Fasciola hepatica and Dicrocoelium dendriticum can be acquired on mountainous pastures by cattle, sheep and other livestock grazing in a transhumant system as intermediate hosts of these parasites may find suitable habitats in these regions. There is evidence that in the prealpine and alpine area both parasites are mainly transmitted in two-season cycles. Further examples for the impact of transhumance on parasite-host inter-relationships include cysticercosis in cattle, echinococcosis, psoroptic manage in sheep, tick-borne fever of cattle, and hypodermosis in cattle. These are described and discussed.

  12. Fishing drives declines in fish parasite diversity and has variable effects on parasite abundance.

    PubMed

    Wood, Chelsea L; Sandin, Stuart A; Zgliczynski, Brian; Guerra, Ana Sofía; Micheli, Fiorenza

    2014-07-01

    Despite the ubiquity and ecological importance of parasites, relatively few studies have assessed their response to anthropogenic environmental change. Heuristic models have predicted both increases and decreases in parasite abundance in response to human disturbance, with empirical support for both. However, most studies focus on one or a few selected parasite species. Here, we assess the abundance of parasites of seven species of coral reef fishes collected from three fished and three unfished islands of the Line Islands archipelago in the central equatorial Pacific. Because we chose fish hosts that spanned different trophic levels, taxonomic groups, and body sizes, we were able to compare parasite responses across a broad cross section of the total parasite community in the presence and absence of fishing, a major human impact on marine ecosystems. We found that overall parasite species richness was substantially depressed on fished islands, but that the response of parasite abundance varied among parasite taxa: directly transmitted parasites were significantly more abundant on fished than on unfished islands, while the reverse was true for trophically transmitted parasites. This probably arises because trophically transmitted parasites require multiple host species, some of which are the top predators most sensitive to fishing impacts. The increase in directly transmitted parasites appeared to be due to fishing-driven compensatory increases in the abundance of their hosts. Together, these results provide support for the predictions of both heuristic models, and indicate that the direction of fishing's impact on parasite abundance is mediated by parasite traits, notably parasite transmission strategies.

  13. Parasitic infections of the gastrointestinal tract.

    PubMed

    Noyer, C M; Brandt, L J

    1999-08-01

    Parasitic infections of the gastrointestinal tract are a major cause of morbidity and mortality worldwide. Increased international travel means that gastroenterologists are now more likely to care for patients with parasitic diseases. This article reviews various aspects of the more common intestinal parasites and their infections, including epidemiology, life cycle, pathogenesis, clinical manifestations, diagnosis, and treatment.

  14. 9 CFR 381.88 - Parasites.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 2 2014-01-01 2014-01-01 false Parasites. 381.88 Section 381.88 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE AGENCY... § 381.88 Parasites. Organs or other parts of carcasses which are found to be infested with parasites,...

  15. 9 CFR 381.88 - Parasites.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 2 2012-01-01 2012-01-01 false Parasites. 381.88 Section 381.88 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE AGENCY... § 381.88 Parasites. Organs or other parts of carcasses which are found to be infested with parasites,...

  16. 9 CFR 381.88 - Parasites.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 2 2011-01-01 2011-01-01 false Parasites. 381.88 Section 381.88 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE AGENCY... § 381.88 Parasites. Organs or other parts of carcasses which are found to be infested with parasites,...

  17. 9 CFR 381.88 - Parasites.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Parasites. 381.88 Section 381.88 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE AGENCY... § 381.88 Parasites. Organs or other parts of carcasses which are found to be infested with parasites,...

  18. 9 CFR 381.88 - Parasites.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 9 Animals and Animal Products 2 2013-01-01 2013-01-01 false Parasites. 381.88 Section 381.88 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE AGENCY... § 381.88 Parasites. Organs or other parts of carcasses which are found to be infested with parasites,...

  19. Fossils of parasites: what can the fossil record tell us about the evolution of parasitism?

    PubMed

    Leung, Tommy L F

    2017-02-01

    Parasites are common in many ecosystems, yet because of their nature, they do not fossilise readily and are very rare in the geological record. This makes it challenging to study the evolutionary transition that led to the evolution of parasitism in different taxa. Most studies on the evolution of parasites are based on phylogenies of extant species that were constructed based on morphological and molecular data, but they give us an incomplete picture and offer little information on many important details of parasite-host interactions. The lack of fossil parasites also means we know very little about the roles that parasites played in ecosystems of the past even though it is known that parasites have significant influences on many ecosystems. The goal of this review is to bring attention to known fossils of parasites and parasitism, and provide a conceptual framework for how research on fossil parasites can develop in the future. Despite their rarity, there are some fossil parasites which have been described from different geological eras. These fossils include the free-living stage of parasites, parasites which became fossilised with their hosts, parasite eggs and propagules in coprolites, and traces of pathology inflicted by parasites on the host's body. Judging from the fossil record, while there were some parasite-host relationships which no longer exist in the present day, many parasite taxa which are known from the fossil record seem to have remained relatively unchanged in their general morphology and their patterns of host association over tens or even hundreds of millions of years. It also appears that major evolutionary and ecological transitions throughout the history of life on Earth coincided with the appearance of certain parasite taxa, as the appearance of new host groups also provided new niches for potential parasites. As such, fossil parasites can provide additional data regarding the ecology of their extinct hosts, since many parasites have

  20. Postcolonial Ecologies of Parasite and Host: Making Parasitism Cosmopolitan.

    PubMed

    Anderson, Warwick

    2016-04-01

    The interest of F. Macfarlane Burnet in host-parasite interactions grew through the 1920s and 1930s, culminating in his book, Biological Aspects of Infectious Disease (1940), often regarded as the founding text of disease ecology. Our knowledge of the influences on Burnet's ecological thinking is still incomplete. Burnet later attributed much of his conceptual development to his reading of British theoretical biology, especially the work of Julian Huxley and Charles Elton, and regretted he did not study Theobald Smith's Parasitism and Disease (1934) until after he had formulated his ideas. Scholars also have adduced Burnet's fascination with natural history and the clinical and public health demands on his research effort, among other influences. I want to consider here additional contributions to Burnet's ecological thinking, focusing on his intellectual milieu, placing his research in a settler society with exceptional expertise in environmental studies and pest management. In part, an ''ecological turn'' in Australian science in the 1930s, derived to a degree from British colonial scientific investments, shaped Burnet's conceptual development. This raises the question of whether we might characterize, in postcolonial fashion, disease ecology, and other studies of parasitism, as successful settler colonial or dominion science.

  1. [Parasitic diseases in the central nervous system].

    PubMed

    Nawa, Yukifumi

    2005-11-01

    Along with the drastic decrease of soil-transmitted intestinal helminthiases, parasitic diseases in general are ignored, or considered as the disease of the past, in Japan. However, due to the Japanese food culture of eating raw materials, food-borne parasitic diseases are still present in Japan. The majority of food-borne parasitic diseases are zoonotic, and caused by ectopic migration of parasite larvae. They accidentally migrate into CNS to cause deleterious conditions. Clinicians should always remind about the possibility of parasitic diseases when they make differential diagnosis for CNS diseases.

  2. Transcriptomics exposes the uniqueness of parasitic plants.

    PubMed

    Ichihashi, Yasunori; Mutuku, J Musembi; Yoshida, Satoko; Shirasu, Ken

    2015-07-01

    Parasitic plants have the ability to obtain nutrients directly from other plants, and several species are serious biological threats to agriculture by parasitizing crops of high economic importance. The uniqueness of parasitic plants is characterized by the presence of a multicellular organ called a haustorium, which facilitates plant-plant interactions, and shutting down or reducing their own photosynthesis. Current technical advances in next-generation sequencing and bioinformatics have allowed us to dissect the molecular mechanisms behind the uniqueness of parasitic plants at the genome-wide level. In this review, we summarize recent key findings mainly in transcriptomics that will give us insights into the future direction of parasitic plant research.

  3. Host Sexual Dimorphism and Parasite Adaptation

    PubMed Central

    Duneau, David; Ebert, Dieter

    2012-01-01

    In species with separate sexes, parasite prevalence and disease expression is often different between males and females. This effect has mainly been attributed to sex differences in host traits, such as immune response. Here, we make the case for how properties of the parasites themselves can also matter. Specifically, we suggest that differences between host sexes in many different traits, such as morphology and hormone levels, can impose selection on parasites. This selection can eventually lead to parasite adaptations specific to the host sex more commonly encountered, or to differential expression of parasite traits depending on which host sex they find themselves in. Parasites adapted to the sex of the host in this way can contribute to differences between males and females in disease prevalence and expression. Considering those possibilities can help shed light on host–parasite interactions, and impact epidemiological and medical science. PMID:22389630

  4. Moonlighting enzymes in parasitic protozoa.

    PubMed

    Collingridge, Peter W; Brown, Robert W B; Ginger, Michael L

    2010-08-01

    Enzymes moonlight in a non-enzymatic capacity in a diverse variety of cellular processes. The discovery of these non-enzymatic functions is generally unexpected, and moonlighting enzymes are known in both prokaryotes and eukaryotes. Importantly, this unexpected multi-functionality indicates that caution might be needed on some occasions in interpreting phenotypes that result from the deletion or gene-silencing of some enzymes, including some of the best known enzymes from classic intermediary metabolism. Here, we provide an overview of enzyme moonlighting in parasitic protists. Unequivocal and putative examples of moonlighting are discussed, together with the possibility that the unusual biological characteristics of some parasites either limit opportunities for moonlighting to arise or perhaps contribute to the evolution of novel proteins with clear metabolic ancestry.

  5. Transfusion-transmitted parasitic infections

    PubMed Central

    Singh, Gagandeep; Sehgal, Rakesh

    2010-01-01

    The transmission of parasitic organisms through transfusion is relatively rare. Of the major transfusion-transmitted diseases, malaria is a major cause of TTIP in tropical countries whereas babesiosis and Chagas’ disease pose the greatest threat to donors in the USA In both cases, this is due to the increased number of potentially infected donors. There are no reliable serologic tests available to screen donors for any of these organisms and the focus for prevention remains on adherence to donor screening guidelines that address travel history and previous infection with the etiologic agent. One goal is the development of tests that are able to screen for and identify donors potentially infectious for parasitic infections without causing the deferral of a large number of non-infectious donors or significantly increasing costs. Ideally, methods to inactivate the infectious organism will provide an element of added safety to the blood supply. PMID:20859503

  6. Transfusion-transmitted parasitic infections.

    PubMed

    Singh, Gagandeep; Sehgal, Rakesh

    2010-07-01

    The transmission of parasitic organisms through transfusion is relatively rare. Of the major transfusion-transmitted diseases, malaria is a major cause of TTIP in tropical countries whereas babesiosis and Chagas' disease pose the greatest threat to donors in the USA In both cases, this is due to the increased number of potentially infected donors. There are no reliable serologic tests available to screen donors for any of these organisms and the focus for prevention remains on adherence to donor screening guidelines that address travel history and previous infection with the etiologic agent. One goal is the development of tests that are able to screen for and identify donors potentially infectious for parasitic infections without causing the deferral of a large number of non-infectious donors or significantly increasing costs. Ideally, methods to inactivate the infectious organism will provide an element of added safety to the blood supply.

  7. Parasitic gastroenteritis in lambs widespread.

    PubMed

    2015-01-24

    Parasitic gastroenteritis diagnosed in lambs by all veterinary investigation centres, Clostridium perfringens epsilon enterotoxaemia suspected in two cows, Comparative quarterly porcine reproductive and respiratory syndrome diagnoses reach a 10-year peak, Failure of an entire colony of gulls in Cumbria, Endoparasitism the predominant feature in exotic farmed animals, These are among matters discussed in the Animal and Plant Health Agency's (APHA's) disease surveillance report for September 2014.

  8. Accumulation of persistent organic pollutants in parasites.

    PubMed

    Yen Le, T T; Rijsdijk, Laurie; Sures, Bern; Hendriks, A Jan

    2014-08-01

    Organisms are simultaneously exposed to various stressors, including parasites and pollutants, that may interact with each other. Research on the accumulation of organic compounds in host-parasite systems is scant compared to studies on parasite-metal interactions and mainly focuses on intestinal endoparasites. We reviewed factors that determine the accumulation of persistent organic pollutants (POPs) in host-parasite systems. The wet/dry weight-based concentration of POPs in these parasites is usually lower than that in host tissues because of lower lipid contents in the parasites. However, the fractionation of the pollutants into parasites and their hosts may vary, depending on developmental stages in the life cycle of the parasites. Developmental stages determine the trophic relationship and the taxon of the parasite in the host-parasite systems because of different feeding strategies between the stages. Lipid-corrected concentrations of organic chemicals in the host are usually higher than those in the endoparasites studied. This phenomenon is attributed to a number of physiological and behavioural processes, such as feeding selectivity and strategy and excretion. Moreover, no significant relationship was found between the accumulation factor (i.e. the ratio between the lipid-corrected concentrations in parasites and in their hosts) for polychlorinated biphenyls and either hydrophobicity or molecular size. At the intermediate hydrophobicity, larger and more lipophilic compounds are accumulated at higher levels in both parasites and the host than smaller and less lipophilic compounds. The bioaccumulation of POPs in parasites is affected by some other abiotic, e.g. temperature, and biotic factors, e.g. the number of host species infected by parasites.

  9. Parasite biodiversity revisited: frontiers and constraints.

    PubMed

    Poulin, Robert

    2014-08-01

    Although parasites are widely touted as representing a large fraction of the Earth's total biodiversity, several questions remain about the magnitude of parasite diversity, our ability to discover it all and how it varies among host taxa or areas of the world. This review addresses four topical issues about parasite diversity. First, we cannot currently estimate how many parasite species there are on Earth with any accuracy, either in relative or absolute terms. Species discovery rates show no sign of slowing down and cryptic parasite species complicate matters further, rendering extrapolation methods useless. Further, expert opinion, which is also used as a means to estimate parasite diversity, is shown here to be prone to serious biases. Second, it seems likely that we may soon not have enough parasite taxonomists to keep up with the description of new species, as taxonomic expertise appears to be limited to a few individuals in the latter stages of their career. Third, we have made great strides toward explaining variation in parasite species richness among host species, by identifying basic host properties that are universal predictors of parasite richness, whatever the type of hosts or parasites. Fourth, in a geographical context, the main driver of variation in parasite species richness across different areas is simply local host species richness; as a consequence, patterns in the spatial variation of parasite species richness tend to match those already well-documented for free-living species. The real value of obtaining good estimates of global parasite diversity is questionable. Instead, our efforts should be focused on ensuring that we maintain sufficient taxonomic resources to keep up with species discovery, and apply what we know of the variation in parasite species richness among host species or across geographical areas to contribute to areas of concern in the ecology of health and in conservation biology.

  10. Eosinophilic fasciitis after parasite infection.

    PubMed

    Oliveira, Marta; Patinha, Fabia; Marinho, Antonio

    2016-01-01

    Eosinophilic fasciitis is a systemic inflammatory disease characterized by symmetrical swelling and skin induration of the distal portions of the arms and/or legs, evolving into a scleroderma-like appearance, accompanied by peripheral blood eosinophilia. It is a rare disease with a poorly understood etiology. Corticosteroid treatment remains the standard therapy, either taken alone or in association with an immunosuppressive drug. This paper presents a case of a male patient with palpebral edema and marked eosinophilia, diagnosed with intestinal parasitic infection in October 2006. He was treated with an antiparasitic drug, but both the swelling and the analytical changes remained. This was followed by a skin and muscle biopsy, which turned out to be compatible with eosinophilic fasciitis. There was progressive worsening of the clinical state, with stiffness of the abdominal wall and elevated inflammatory parameters, and the patient was referred to the Immunology Department, medicated with corticosteroids and methotrexate. Over the years there were therapeutic adjustments and other causes were excluded. Currently the patient continues to be monitored, and there is no evidence of active disease. The case described in this article is interesting because of the diagnosis of eosinophilic fasciitis probably associated/coexisting with a parasite infection. This case report differs from others in that there is an uncommon cause associated with the onset of the disease, instead of the common causes such as trauma, medication, non-parasitic infections or cancer.

  11. Fauna Europaea: Helminths (Animal Parasitic)

    PubMed Central

    Bray, Rodney A.; Hunt, David; Georgiev, Boyko B.; Scholz, Tomaš; Harris, Philip D.; Bakke, Tor A.; Pojmanska, Teresa; Niewiadomska, Katarzyna; Kostadinova, Aneta; Tkach, Vasyl; Bain, Odile; Durette-Desset, Marie-Claude; Gibbons, Lynda; Moravec, František; Petter, Annie; Dimitrova, Zlatka M.; Buchmann, Kurt; Valtonen, E. Tellervo; de Jong, Yde

    2014-01-01

    Abstract Fauna Europaea provides a public web-service with an index of scientific names (including important synonyms) of all living European land and freshwater animals, their geographical distribution at country level (up to the Urals, excluding the Caucasus region), and some additional information. The Fauna Europaea project covers about 230,000 taxonomic names, including 130,000 accepted species and 14,000 accepted subspecies, which is much more than the originally projected number of 100,000 species. This represents a huge effort by more than 400 contributing specialists throughout Europe and is a unique (standard) reference suitable for many users in science, government, industry, nature conservation and education. Helminths parasitic in animals represent a large assemblage of worms, representing three phyla, with more than 200 families and almost 4,000 species of parasites from all major vertebrate and many invertebrate groups. A general introduction is given for each of the major groups of parasitic worms, i.e. the Acanthocephala, Monogenea, Trematoda (Aspidogastrea and Digenea), Cestoda and Nematoda. Basic information for each group includes its size, host-range, distribution, morphological features, life-cycle, classification, identification and recent key-works. Tabulations include a complete list of families dealt with, the number of species in each and the name of the specialist responsible for data acquisition, a list of additional specialists who helped with particular groups, and a list of higher taxa dealt with down to the family level. A compilation of useful references is appended. PMID:25349520

  12. Cardiac manifestations of parasitic diseases.

    PubMed

    Nunes, Maria Carmo P; Guimarães Júnior, Milton Henriques; Diamantino, Adriana Costa; Gelape, Claudio Leo; Ferrari, Teresa Cristina Abreu

    2017-03-11

    The heart may be affected directly or indirectly by a variety of protozoa and helminths. This involvement may manifest in different ways, but the syndromes resulting from impairment of the myocardium and pericardium are the most frequent. The myocardium may be invaded by parasites that trigger local inflammatory response with subsequent myocarditis or cardiomyopathy, as occurs in Chagas disease, African trypanosomiasis, toxoplasmosis, trichinellosis and infection with free-living amoebae. In amoebiasis and echinococcosis, the pericardium is the structure most frequently involved with consequent pericardial effusion, acute pericarditis, cardiac tamponade or constrictive pericarditis. Chronic hypereosinophilia due to helminth infections, especially filarial infections, has been associated with the development of tropical endomyocardial fibrosis, a severe form of restrictive cardiomyopathy. Schistosomiasis-associated lung vasculature involvement may cause pulmonary hypertension (PH) and cor pulmonale Tropical pulmonary eosinophilia, which is characterised by progressive interstitial fibrosis and restrictive lung disease, may lead to PH and its consequences may occur in the course of filarial infections. Intracardiac rupture of an Echinococcus cyst can cause membrane or secondary cysts embolisation to the lungs or organs supplied by the systemic circulation. Although unusual causes of cardiac disease outside the endemic areas, heart involvement by parasites should be considered in the differential diagnosis especially of myocardial and/or pericardial diseases of unknown aetiology in both immunocompetent and immunocompromised individuals. In this review, we updated and summarised the current knowledge on the major heart diseases caused by protozoan and metazoan parasites, which either involve the heart directly or otherwise influence the heart adversely.

  13. Fauna europaea: helminths (animal parasitic).

    PubMed

    Gibson, David I; Bray, Rodney A; Hunt, David; Georgiev, Boyko B; Scholz, Tomaš; Harris, Philip D; Bakke, Tor A; Pojmanska, Teresa; Niewiadomska, Katarzyna; Kostadinova, Aneta; Tkach, Vasyl; Bain, Odile; Durette-Desset, Marie-Claude; Gibbons, Lynda; Moravec, František; Petter, Annie; Dimitrova, Zlatka M; Buchmann, Kurt; Valtonen, E Tellervo; de Jong, Yde

    2014-01-01

    Fauna Europaea provides a public web-service with an index of scientific names (including important synonyms) of all living European land and freshwater animals, their geographical distribution at country level (up to the Urals, excluding the Caucasus region), and some additional information. The Fauna Europaea project covers about 230,000 taxonomic names, including 130,000 accepted species and 14,000 accepted subspecies, which is much more than the originally projected number of 100,000 species. This represents a huge effort by more than 400 contributing specialists throughout Europe and is a unique (standard) reference suitable for many users in science, government, industry, nature conservation and education. Helminths parasitic in animals represent a large assemblage of worms, representing three phyla, with more than 200 families and almost 4,000 species of parasites from all major vertebrate and many invertebrate groups. A general introduction is given for each of the major groups of parasitic worms, i.e. the Acanthocephala, Monogenea, Trematoda (Aspidogastrea and Digenea), Cestoda and Nematoda. Basic information for each group includes its size, host-range, distribution, morphological features, life-cycle, classification, identification and recent key-works. Tabulations include a complete list of families dealt with, the number of species in each and the name of the specialist responsible for data acquisition, a list of additional specialists who helped with particular groups, and a list of higher taxa dealt with down to the family level. A compilation of useful references is appended.

  14. A Lymphatic dwelling filarioid nematode, Rumenfilaria andersoni (Filarioidea; Splendidofilariinae), is an emerging parasite in Finnish cervids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background-Recent studies revealed expansion of filarioid nematodes into the northern Finland. In addition to Setaria tundra, unidentified and very abundant filarioids, representing Rumenfilaria andersoni, were found inhabiting the lymphatic vessels of reindeer. Our study explores the biology and d...

  15. Parasites as prey in aquatic food webs: implications for predator infection and parasite transmission

    USGS Publications Warehouse

    Thieltges, David W.; Amundsen, Per-Arne; Hechinger, Ryan F.; Johnson, Pieter T.J.; Lafferty, Levin D.; Mouritsen, Kim N.; Preston, Daniel L.; Reise, Karsten; Zander, C. Dieter; Poulin, Robert

    2013-01-01

    While the recent inclusion of parasites into food-web studies has highlighted the role of parasites as consumers, there is accumulating evidence that parasites can also serve as prey for predators. Here we investigated empirical patterns of predation on parasites and their relationships with parasite transmission in eight topological food webs representing marine and freshwater ecosystems. Within each food web, we examined links in the typical predator–prey sub web as well as the predator–parasite sub web, i.e. the quadrant of the food web indicating which predators eat parasites. Most predator– parasite links represented ‘concomitant predation’ (consumption and death of a parasite along with the prey/host; 58–72%), followed by ‘trophic transmission’ (predator feeds on infected prey and becomes infected; 8–32%) and predation on free-living parasite life-cycle stages (4–30%). Parasite life-cycle stages had, on average, between 4.2 and 14.2 predators. Among the food webs, as predator richness increased, the number of links exploited by trophically transmitted parasites increased at about the same rate as did the number of links where these stages serve as prey. On the whole, our analyses suggest that predation on parasites has important consequences for both predators and parasites, and food web structure. Because our analysis is solely based on topological webs, determining the strength of these interactions is a promising avenue for future research.

  16. Fossil Crustaceans as Parasites and Hosts.

    PubMed

    Klompmaker, Adiël A; Boxshall, Geoff A

    2015-01-01

    Numerous crustacean lineages have independently moved into parasitism as a mode of life. In modern marine ecosystems, parasitic crustaceans use representatives from many metazoan phyla as hosts. Crustaceans also serve as hosts to a rich diversity of parasites, including other crustaceans. Here, we show that the fossil record of such parasitic interactions is sparse, with only 11 examples, one dating back to the Cambrian. This may be due to the limited preservation potential and small size of parasites, as well as to problems with ascribing traces to parasitism with certainty, and to a lack of targeted research. Although the confirmed stratigraphic ranges are limited for nearly every example, evidence of parasitism related to crustaceans has become increasingly more complete for isopod-induced swellings in decapods so that quantitative analyses can be carried out. Little attention has yet been paid to the origin of parasitism in deep time, but insight can be generated by integrating data on fossils with molecular studies on modern parasites. In addition, there are other traces left by parasites that could fossilize, but have not yet been recognized in the fossil record.

  17. Introduced species and their missing parasites

    USGS Publications Warehouse

    Torchin, Mark E.; Lafferty, Kevin D.; Dobson, Andrew P.; McKenzie, Valerie J.; Kuris, Armand M.

    2003-01-01

    Damage caused by introduced species results from the high population densities and large body sizes that they attain in their new location. Escape from the effects of natural enemies is a frequent explanation given for the success of introduced species. Because some parasites can reduce host density and decrease body size, an invader that leaves parasites behind and encounters few new parasites can experience a demographic release and become a pest. To test whether introduced species are less parasitized, we have compared the parasites of exotic species in their native and introduced ranges, using 26 host species of molluscs, crustaceans, fishes, birds, mammals, amphibians and reptiles. Here we report that the number of parasite species found in native populations is twice that found in exotic populations. In addition, introduced populations are less heavily parasitized (in terms of percentage infected) than are native populations. Reduced parasitization of introduced species has several causes, including reduced probability of the introduction of parasites with exotic species (or early extinction after host establishment), absence of other required hosts in the new location, and the host-specific limitations of native parasites adapting to new hosts.

  18. Cleaning symbioses from the parasites' perspective.

    PubMed

    Grutter, A S

    2002-01-01

    Cleaning behaviour has generally been viewed from the cleaner or client's point of view. Few studies, however, have examined cleaning behaviour from the parasites' perspective, yet they are the equally-important third players in such associations. All three players are likely to have had their evolution affected by the association. As cleaner organisms are important predators of parasites, cleaners are likely to have an important effect on their prey. Little, however, is known of how parasites are affected by cleaning associations and the strategies that parasites use in response to cleaners. I examine here what parasites are involved in cleaning interactions, the effect cleaners have on parasites, the potential counteradaptations that parasites have evolved against the predatory activities of cleaner organisms, the potential influence of cleaners on the life history traits of parasites, and other factors affected by cleaners. I have found that a wide range of ectoparasites from diverse habitats have been reported to interact with a wide range of cleaner organisms. Some of the life history traits of parasites are consistent with the idea that they are in response to cleaner predation. It is clear, however, that although many cleaning systems exist their ecological role is largely unexplored. This has likely been hindered by our lack of information on the parasites involved in cleaning interactions.

  19. Ecological consequences of manipulative parasites: chapter 9

    USGS Publications Warehouse

    Lafferty, Kevin D.; Kuris, A. M.

    2012-01-01

    Parasitic "puppet masters", with their twisted, self-serving life history strategies and impressive evolutionary takeovers of host minds, capture the imagination of listeners—even those that might not normally fi nd the topic of parasitism appealing (which includes most everyone). A favorite anecdote concerns the trematode Leucochloridium paradoxum migrating to the eyestalks of its intermediate host snail and pulsating its colored body, presumably to attract the predatory birds that are the final hosts for the worm. Identifying a parasite as “manipulative” infers that a change in host behavior or appearance is a direct consequence of the parasite’s adaptive actions that, on average, will increase the fi tness of the parasite. The list of parasites that manipulate their hosts is long and growing. Holmes and Bethel (1972) presented the earliest comprehensive review and brought the subject to mainstream ecologists. Over two decades ago, Andy Dobson (1988) listed seven cestodes, seven trematodes, ten acanthocephalans, and three nematodes that manipulated host behavior. Fifteen years later, Janice Moore (2002) filled a book with examples. The five infectious trophic strategies, typical parasites (macroparasites), pathogens, trophically transmitted parasites, parasitic castrators, and parasitoids (Kuris and Lafferty 2000; Lafferty and Kuris 2002, 2009) can modify host behavior, but the likelihood that a parasite manipulates behavior differs among strategies. The most studied infectious agents, non-trophically transmitted pathogens and macroparasites, have enormous public health, veterinary, and wildlife disease importance, yet few manipulate host behavior. The beststudied manipulative infectious agents are trophically transmitted parasites in their prey intermediate hosts. Parasitoids and parasitic castrators can also manipulate host behavior, but for different purposes and with different implications. Several studies of manipulative parasites conclude with

  20. An ABA-responsive DRE-binding protein gene from Setaria italica, SiARDP, the target gene of SiAREB, plays a critical role under drought stress

    PubMed Central

    Li, Cong; Yue, Jing; Wu, Xiaowei; Xu, Cong; Yu, Jingjuan

    2014-01-01

    The DREB (dehydration-responsive element binding)-type transcription factors regulate the expression of stress-inducible genes by binding the DRE/CRT cis-elements in promoter regions. The upstream transcription factors that regulate the transcription of DREB transcription factors have not been clearly defined, although the function of DREB transcription factors in abiotic stress is known. In this study, an abscisic acid (ABA)-responsive DREB-binding protein gene (SiARDP) was cloned from foxtail millet (Setaria italica). The transcript level of SiARDP increased not only after drought, high salt, and low temperature stresses, but also after an ABA treatment in foxtail millet seedlings. Two ABA-responsive elements (ABRE1: ACGTGTC; ABRE2: ACGTGGC) exist in the promoter of SiARDP. Further analyses showed that two ABA-responsive element binding (AREB)-type transcription factors, SiAREB1 and SiAREB2, could physically bind to the ABRE core element in vitro and in vivo. The constitutive expression of SiARDP in Arabidopsis thaliana enhanced drought and salt tolerance during seed germination and seedling development, and overexpression of SiARDP in foxtail millet improved drought tolerance. The expression levels of target genes of SiARDP were upregulated in transgenic Arabidopsis and foxtail millet. These results reveal that SiARDP, one of the target genes of SiAREB, is involved in ABA-dependent signal pathways and plays a critical role in the abiotic stress response in plants. PMID:25071221

  1. The C-terminal motif of SiAGO1b is required for the regulation of growth, development and stress responses in foxtail millet (Setaria italica (L.) P. Beauv)

    PubMed Central

    Liu, Xiaotong; Tang, Sha; Jia, Guanqing; Schnable, James C.; Su, Haixia; Tang, Chanjuan; Zhi, Hui; Diao, Xianmin

    2016-01-01

    Foxtail millet (Setaria italica (L.) P. Beauv), which belongs to the Panicoideae tribe of the Poaceae, is an important grain crop widely grown in Northern China and India. It is currently developing into a novel model species for functional genomics of the Panicoideae as a result of its fully available reference genome sequence, small diploid genome (2n=18, ~510Mb), short life cycle, small stature and prolific seed production. Argonaute 1 (AGO1), belonging to the argonaute (AGO) protein family, recruits small RNAs and regulates plant growth and development. Here, we characterized an AGO1 mutant (siago1b) in foxtail millet, which was induced by ethyl methanesulfonate treatment. The mutant exhibited pleiotropic developmental defects, including dwarfing stem, narrow and rolled leaves, smaller panicles and lower rates of seed setting. Map-based cloning analysis demonstrated that these phenotypic variations were attributed to a C–A transversion, and a 7-bp deletion in the C-terminus of the SiAGO1b gene in siago1b. Yeast two-hybrid assays and BiFC experiments revealed that the mutated region was an essential functional motif for the interaction between SiAGO1b and SiHYL1. Furthermore, 1598 differentially expressed genes were detected via RNA-seq-based comparison of SiAGO1b and wild-type plants, which revealed that SiAGO1b mutation influenced multiple biological processes, including energy metabolism, cell growth, programmed death and abiotic stress responses in foxtail millet. This study may provide a better understanding of the mechanisms by which SiAGO1b regulates the growth and development of crops. PMID:27045099

  2. When parasites disagree: Evidence for parasite-induced sabotage of host manipulation

    PubMed Central

    Hafer, Nina; Milinski, Manfred

    2015-01-01

    Host manipulation is a common parasite strategy to alter host behavior in a manner to enhance parasite fitness usually by increasing the parasite's transmission to the next host. In nature, hosts often harbor multiple parasites with agreeing or conflicting interests over host manipulation. Natural selection might drive such parasites to cooperation, compromise, or sabotage. Sabotage would occur if one parasite suppresses the manipulation of another. Experimental studies on the effect of multi-parasite interactions on host manipulation are scarce, clear experimental evidence for sabotage is elusive. We tested the effect of multiple infections on host manipulation using laboratory-bred copepods experimentally infected with the trophically transmitted tapeworm Schistocephalus solidus. This parasite is known to manipulate its host depending on its own developmental stage. Coinfecting parasites with the same aim enhance each other's manipulation but only after reaching infectivity. If the coinfecting parasites disagree over host manipulation, the infective parasite wins this conflict: the noninfective one has no effect. The winning (i.e., infective) parasite suppresses the manipulation of its noninfective competitor. This presents conclusive experimental evidence for both cooperation in and sabotage of host manipulation and hence a proof of principal that one parasite can alter and even neutralize manipulation by another. PMID:25643621

  3. Random parasite encounters coupled with condition-linked immunity of hosts generate parasite aggregation.

    PubMed

    Morrill, André; Forbes, Mark R

    2012-06-01

    Parasite aggregation is viewed as a natural law in parasite-host ecology but is a paradox insofar as parasites should follow the Poisson distribution if hosts are encountered randomly. Much research has focused on whether parasite aggregation in or on hosts is explained by aggregation of infective parasite stages in the environment, or by heterogeneity within host samples in terms of host responses to infection (e.g., through representation of different age classes of hosts). In this paper, we argue that the typically aggregated distributions of parasites may be explained simply. We propose that aggregated distributions can be derived from parasites encountering hosts randomly, but subsequently by parasites being 'lost' from hosts based on condition-linked escape or immunity of hosts. Host condition should be a normally distributed trait even among otherwise homogeneous sets of hosts. Our model shows that mean host condition and variation in host condition have different effects on the different metrics of parasite aggregation. Our model further predicts that as host condition increases, parasites become more aggregated but numbers of attending parasites are reduced overall and this is important for parasite population dynamics. The effects of deviation from random encounter are discussed with respect to the relationship between host condition and final parasite numbers.

  4. When parasites disagree: evidence for parasite-induced sabotage of host manipulation.

    PubMed

    Hafer, Nina; Milinski, Manfred

    2015-03-01

    Host manipulation is a common parasite strategy to alter host behavior in a manner to enhance parasite fitness usually by increasing the parasite's transmission to the next host. In nature, hosts often harbor multiple parasites with agreeing or conflicting interests over host manipulation. Natural selection might drive such parasites to cooperation, compromise, or sabotage. Sabotage would occur if one parasite suppresses the manipulation of another. Experimental studies on the effect of multi-parasite interactions on host manipulation are scarce, clear experimental evidence for sabotage is elusive. We tested the effect of multiple infections on host manipulation using laboratory-bred copepods experimentally infected with the trophically transmitted tapeworm Schistocephalus solidus. This parasite is known to manipulate its host depending on its own developmental stage. Coinfecting parasites with the same aim enhance each other's manipulation but only after reaching infectivity. If the coinfecting parasites disagree over host manipulation, the infective parasite wins this conflict: the noninfective one has no effect. The winning (i.e., infective) parasite suppresses the manipulation of its noninfective competitor. This presents conclusive experimental evidence for both cooperation in and sabotage of host manipulation and hence a proof of principal that one parasite can alter and even neutralize manipulation by another.

  5. Parasitic diseases in the abdomen: imaging findings.

    PubMed

    Lim, Jae Hoon

    2008-01-01

    Parasitic diseases of the liver and biliary tract include echinococcosis, schistosomiasis, toxocariasis, clonorchiasis, and opisthorchiasis, affecting millions people in some endemic areas. Amebiasis and ascariasis are believed to be the most common bowel lumen indwelling parasitic diseases, affecting billions people worldwide, but sometimes these parasites migrate inadvertently to the liver and biliary tract, resulting in liver abscess or obstructive jaundice. Imaging findings of these parasitic diseases are fairly characteristic and easy to recognize if radiologists are aware of the findings, especially in endemic areas. Because of increased immigration and frequent travelling, some patients with "exotic" parasitic diseases may be encountered in non-endemic areas, and the diagnosis may be delayed or difficult, and it is often made only after operation. This feature section was designed to provide the detailed imaging features of common parasitic diseases affecting the abdominal organs and peritoneal cavity, based on pathology-image correlation.

  6. [Anisakiasis - a little-known parasitic zoonosis].

    PubMed

    Bardoň, Jan; Harna, Jiří; Pijáček, Martin

    2013-06-01

    Parasites of the family Anisakidae cause enteric parasitic zoonoses developing after consumption of inadequately cooked marine fish. Cases of such diseases are reported mainly from Japan or other countries where raw or uncooked fish are traditionally consumed. The presented short communication briefly reports detection of larvae of Pseudoterranova spp., parasites of the family Anisakidae, in a fresh chilled angler-fish (Lophius piscatorius) bought at a retail store in the Czech Republic.

  7. Parasites in bloom: flowers aid dispersal and transmission of pollinator parasites within and between bee species

    PubMed Central

    Graystock, Peter; Goulson, Dave; Hughes, William O. H.

    2015-01-01

    The dispersal of parasites is critical for epidemiology, and the interspecific vectoring of parasites when species share resources may play an underappreciated role in parasite dispersal. One of the best examples of such a situation is the shared use of flowers by pollinators, but the importance of flowers and interspecific vectoring in the dispersal of pollinator parasites is poorly understood and frequently overlooked. Here, we use an experimental approach to show that during even short foraging periods of 3 h, three bumblebee parasites and two honeybee parasites were dispersed effectively onto flowers by their hosts, and then vectored readily between flowers by non-host pollinator species. The results suggest that flowers are likely to be hotspots for the transmission of pollinator parasites and that considering potential vector, as well as host, species will be of general importance for understanding the distribution and transmission of parasites in the environment and between pollinators. PMID:26246556

  8. Parasites in bloom: flowers aid dispersal and transmission of pollinator parasites within and between bee species.

    PubMed

    Graystock, Peter; Goulson, Dave; Hughes, William O H

    2015-08-22

    The dispersal of parasites is critical for epidemiology, and the interspecific vectoring of parasites when species share resources may play an underappreciated role in parasite dispersal. One of the best examples of such a situation is the shared use of flowers by pollinators, but the importance of flowers and interspecific vectoring in the dispersal of pollinator parasites is poorly understood and frequently overlooked. Here, we use an experimental approach to show that during even short foraging periods of 3 h, three bumblebee parasites and two honeybee parasites were dispersed effectively onto flowers by their hosts, and then vectored readily between flowers by non-host pollinator species. The results suggest that flowers are likely to be hotspots for the transmission of pollinator parasites and that considering potential vector, as well as host, species will be of general importance for understanding the distribution and transmission of parasites in the environment and between pollinators.

  9. Parasites in the Wadden Sea food web

    NASA Astrophysics Data System (ADS)

    Thieltges, David W.; Engelsma, Marc Y.; Wendling, Carolin C.; Wegner, K. Mathias

    2013-09-01

    While the free-living fauna of the Wadden Sea has received much interest, little is known on the distribution and effects of parasites in the Wadden Sea food web. However, recent studies on this special type of trophic interaction indicate a high diversity of parasites in the Wadden Sea and suggest a multitude of effects on the hosts. This also includes effects on specific predator-prey relationships and the general structure of the food web. Focussing on molluscs, a major group in the Wadden Sea in terms of biomass and abundance and an important link between primary producers and predators, we review existing studies and exemplify the ecological role of parasites in the Wadden Sea food web. First, we give a brief inventory of parasites occurring in the Wadden Sea, ranging from microparasites (e.g. protozoa, bacteria) to macroparasites (e.g. helminths, parasitic copepods) and discuss the effects of spatial scale on heterogeneities in infection levels. We then demonstrate how parasites can affect host population dynamics by acting as a strong mortality factor, causing mollusc mass mortalities. In addition, we will exemplify how parasites can mediate the interaction strength of predator-prey relationships and affect the topological structure of the Wadden Sea food web as a whole. Finally, we highlight some ongoing changes regarding parasitism in the Wadden Sea in the course of global change (e.g. species introduction, climate change) and identify important future research questions to entangle the role of parasites in the Wadden Sea food web.

  10. Effects of a hurricane on fish parasites.

    PubMed

    Overstreet, R M

    2007-09-01

    Hurricanes, also called tropical cyclones, can dramatically affect life along their paths, including a temporary losing or reducing in number of parasites of fishes. Hurricane Katrina in the northern Gulf of Mexico in August 2005 provides many examples involving humans and both terrestrial and aquatic animals and plants. Fishes do not provide much of an indicator of hurricane activity because most species quickly repopulate the area. Fish parasites, however, serve as a good indicator of the overall biodiversity and environmental health. The reasons for the noted absence or reduction of parasites in fishes are many, and specific parasites provide indications of different processes. The powerful winds can produce perturbations of the sediments harboring intermediate hosts. The surge of high salinity water can kill or otherwise affect low salinity intermediate hosts or free-living stages. Both can introduce toxicants into the habitat and also interfere with the timing and processes involved with host-parasite interrelationships. All these have had a major influence on fish parasite populations of fishes in coastal Mississippi, especially for those parasites incorporating intermediate hosts in their life cycles. The length of time for a parasite to become re-established can vary considerably, depending on its life cycle as well as the associated biota, habitat, and environmental conditions, and each parasite provides a special indicator of environmental health.

  11. Apoptotic markers in protozoan parasites

    PubMed Central

    2010-01-01

    The execution of the apoptotic death program in metazoans is characterized by a sequence of morphological and biochemical changes that include cell shrinkage, presentation of phosphatidylserine at the cell surface, mitochondrial alterations, chromatin condensation, nuclear fragmentation, membrane blebbing and the formation of apoptotic bodies. Methodologies for measuring apoptosis are based on these markers. Except for membrane blebbing and formation of apoptotic bodies, all other events have been observed in most protozoan parasites undergoing cell death. However, while techniques exist to detect these markers, they are often optimised for metazoan cells and therefore may not pick up subtle differences between the events occurring in unicellular organisms and multi-cellular organisms. In this review we discuss the markers most frequently used to analyze cell death in protozoan parasites, paying special attention to changes in cell morphology, mitochondrial activity, chromatin structure and plasma membrane structure/permeability. Regarding classical regulators/executors of apoptosis, we have reviewed the present knowledge of caspase-like and nuclease activities. PMID:21062457

  12. [Discussion on the usage of terminology of some parasites and parasitic diseases].

    PubMed

    Wang, Zhong-quan; Cui, Jing

    2006-04-30

    According to the International Code of Zoological Nomenclature and the Standardized Nomenclature of Animal Parasitic Diseases (SNOAPAD), and considering the new advances in parasitology, the usage of the terminology of some parasites and parasitic diseases (such as Trichinella and trichinellosis, filariae and filariasis, Echinococcus and echinococcosis, etc.) was discussed.

  13. How Many Parasites Species a Frog Might Have? Determinants of Parasite Diversity in South American Anurans

    PubMed Central

    Campião, Karla Magalhães; Ribas, Augusto Cesar de Aquino; Morais, Drausio Honorio; da Silva, Reinaldo José; Tavares, Luiz Eduardo Roland

    2015-01-01

    There is an increasing interest in unveiling the dynamics of parasite infection. Understanding the interaction patterns, and determinants of host-parasite association contributes to filling knowledge gaps in both community and disease ecology. Despite being targeted as a relevant group for conservation efforts, determinants of the association of amphibians and their parasites in broad scales are poorly understood. Here we describe parasite biodiversity in South American amphibians, testing the influence of host body size and geographic range in helminth parasites species richness (PSR). We also test whether parasite diversity is related to hosts’ phylogenetic diversity. Results showed that nematodes are the most common anuran parasites. Host-parasite network has a nested pattern, with specialist helminth taxa generally associated with hosts that harbour the richest parasite faunas. Host size is positively correlated with helminth fauna richness, but we found no support for the association of host geographic range and PSR. These results remained consistent after correcting for uneven study effort and hosts’ phylogenic correlation. However, we found no association between host and parasite diversity, indicating that more diversified anuran clades not necessarily support higher parasite diversity. Overall, considering both the structure and the determinants of PRS in anurans, we conclude that specialist parasites are more likely to be associated with large anurans, which are the ones harbouring higher PSR, and that the lack of association of PSR with hosts’ clade diversification suggests it is strongly influenced by ecological and contemporary constrains. PMID:26473593

  14. How Many Parasites Species a Frog Might Have? Determinants of Parasite Diversity in South American Anurans.

    PubMed

    Campião, Karla Magalhães; Ribas, Augusto Cesar de Aquino; Morais, Drausio Honorio; da Silva, Reinaldo José; Tavares, Luiz Eduardo Roland

    2015-01-01

    There is an increasing interest in unveiling the dynamics of parasite infection. Understanding the interaction patterns, and determinants of host-parasite association contributes to filling knowledge gaps in both community and disease ecology. Despite being targeted as a relevant group for conservation efforts, determinants of the association of amphibians and their parasites in broad scales are poorly understood. Here we describe parasite biodiversity in South American amphibians, testing the influence of host body size and geographic range in helminth parasites species richness (PSR). We also test whether parasite diversity is related to hosts' phylogenetic diversity. Results showed that nematodes are the most common anuran parasites. Host-parasite network has a nested pattern, with specialist helminth taxa generally associated with hosts that harbour the richest parasite faunas. Host size is positively correlated with helminth fauna richness, but we found no support for the association of host geographic range and PSR. These results remained consistent after correcting for uneven study effort and hosts' phylogenic correlation. However, we found no association between host and parasite diversity, indicating that more diversified anuran clades not necessarily support higher parasite diversity. Overall, considering both the structure and the determinants of PRS in anurans, we conclude that specialist parasites are more likely to be associated with large anurans, which are the ones harbouring higher PSR, and that the lack of association of PSR with hosts' clade diversification suggests it is strongly influenced by ecological and contemporary constrains.

  15. Parasites and cancers: parasite antigens as possible targets for cancer immunotherapy.

    PubMed

    Darani, Hossein Yousofi; Yousefi, Morteza

    2012-12-01

    An adverse relationship between some parasite infections and cancer in the human population has been reported by different research groups. Anticancer activity of some parasites such as Trypanosoma cruzi, Toxoplasma gondii, Toxocara canis, Acantamoeba castellani and Plasmodium yoelii has been shown in experimental animals. Moreover, it has been shown that cancer-associated mucin-type O-glycan compositions are made by parasites, therefore cancers and parasites have common antigens. In this report anticancer activities of some parasites have been reviewed and the possible mechanisms of these actions have also been discussed.

  16. Malaria Parasite Liver Infection and Exoerythrocytic Biology.

    PubMed

    Vaughan, Ashley M; Kappe, Stefan H I

    2017-02-27

    In their infection cycle, malaria parasites undergo replication and population expansions within the vertebrate host and the mosquito vector. Host infection initiates with sporozoite invasion of hepatocytes, followed by a dramatic parasite amplification event during liver stage parasite growth and replication within hepatocytes. Each liver stage forms up to 90,000 exoerythrocytic merozoites, which are in turn capable of initiating a blood stage infection. Liver stages not only exploit host hepatocyte resources for nutritional needs but also endeavor to prevent hepatocyte cell death and detection by the host's immune system. Research over the past decade has identified numerous parasite factors that play a critical role during liver infection and has started to delineate a complex web of parasite-host interactions that sustain successful parasite colonization of the mammalian host. Targeting the parasites' obligatory infection of the liver as a gateway to the blood, with drugs and vaccines, constitutes the most effective strategy for malaria eradication, as it would prevent clinical disease and onward transmission of the parasite.

  17. Parasite stress promotes homicide and child maltreatment.

    PubMed

    Thornhill, Randy; Fincher, Corey L

    2011-12-12

    Researchers using the parasite-stress theory of human values have discovered many cross-cultural behavioural patterns that inform a range of scholarly disciplines. Here, we apply the theory to major categories of interpersonal violence, and the empirical findings are supportive. We hypothesize that the collectivism evoked by high parasite stress is a cause of adult-on-adult interpersonal violence. Across the US states, parasite stress and collectivism each positively predicts rates of men's and women's slaying of a romantic partner, as well as the rate of male-honour homicide and of the motivationally similar felony-related homicide. Of these four types of homicide, wealth inequality has an independent effect only on rates of male-honour and felony-related homicide. Parasite stress and collectivism also positively predict cross-national homicide rates. Child maltreatment by caretakers is caused, in part, by divestment in offspring of low phenotypic quality, and high parasite stress produces more such offspring than low parasite stress. Rates of each of two categories of the child maltreatment--lethal and non-lethal--across the US states are predicted positively by parasite stress, with wealth inequality and collectivism having limited effects. Parasite stress may be the strongest predictor of interpersonal violence to date.

  18. Realizing the promise of parasite genomics.

    PubMed

    Wasmuth, James D

    2014-07-01

    Genomes and genomics are now part of the popular imagination and culture. Understanding what these massively long strings of As, Gs, Cs, and Ts actually mean is a challenge that has been taken up by many working on parasites. Our understanding of parasite biology and future treatment strategies has been significantly improved because of these genomes.

  19. Infectious diseases and parasites of ratites.

    PubMed

    Shane, S M

    1998-11-01

    This article discusses infectious and parasitic disease conditions in the three ratite species. Diseases and parasitic conditions are reviewed in relation to etiology, transmission, pathology, diagnosis, treatment, and prevention. To ensure optimum reproduction and growth of birds on large production units, a veterinarian must understand management in relation to biosecurity and disease problems.

  20. 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.

  1. Parasite stress promotes homicide and child maltreatment

    PubMed Central

    Thornhill, Randy; Fincher, Corey L.

    2011-01-01

    Researchers using the parasite-stress theory of human values have discovered many cross-cultural behavioural patterns that inform a range of scholarly disciplines. Here, we apply the theory to major categories of interpersonal violence, and the empirical findings are supportive. We hypothesize that the collectivism evoked by high parasite stress is a cause of adult-on-adult interpersonal violence. Across the US states, parasite stress and collectivism each positively predicts rates of men's and women's slaying of a romantic partner, as well as the rate of male-honour homicide and of the motivationally similar felony-related homicide. Of these four types of homicide, wealth inequality has an independent effect only on rates of male-honour and felony-related homicide. Parasite stress and collectivism also positively predict cross-national homicide rates. Child maltreatment by caretakers is caused, in part, by divestment in offspring of low phenotypic quality, and high parasite stress produces more such offspring than low parasite stress. Rates of each of two categories of the child maltreatment—lethal and non-lethal—across the US states are predicted positively by parasite stress, with wealth inequality and collectivism having limited effects. Parasite stress may be the strongest predictor of interpersonal violence to date. PMID:22042922

  2. The parasite connection in ecosystems and macroevolution.

    PubMed

    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.

  3. First report of Orobanche ludoviciana parasitizing sunflowers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Broomrape is the common name given to a group of flowering plants belonging to the genus Orobanche that parasitize the roots of higher dicotyledonous plants. More than 100 species of Orobanche have been identified, all of which are obligate parasites that lack chlorophyll and depend upon their host ...

  4. A hypermedia system for parasite identification.

    PubMed

    Lalle, C

    1996-06-01

    In this paper a hypermedia system for parasite identification is described. The knowledge base is relative to the class of the Trematoda parasites and reports agent, vector, disease, related category of the International Classification of Diseases and geographic area. A graphic user-friendly human-machine interface has been realized for this system.

  5. Update on pathology of ocular parasitic disease

    PubMed Central

    Das, Dipankar; Ramachandra, Varsha; Islam, Saidul; Bhattacharjee, Harsha; Biswas, Jyotirmay; Koul, Akanksha; Deka, Panna; Deka, Apurba

    2016-01-01

    Parasites are a group of eukaryotic organisms that may be free-living or form a symbiotic or parasitic relationship with the hosts. Consisting of over 800,000 recognized species, parasites may be unicellular (Protozoa) or multicellular (helminths and arthropods). The association of parasites with human population started long before the emergence of civilization. Parasitic zoonotic diseases are prevalent worldwide including India. Appropriate epidemiological data are lacking on existing zoonotic parasitic diseases, and newer diseases are emerging in our scenario. Systemic diseases such as cysticercosis, paragonimiasis, hydatidosis, and toxoplasmosis are fairly common. Acquired Toxoplasma infections are rising in immune-deficient individuals. Amongst the ocular parasitic diseases, various protozoas such as Cystoidea, trematodes, tissue flagellates, sporozoas etc. affect humans in general and eyes in particular, in different parts of the world. These zoonoses seem to be a real health related problem globally. Recent intensification of research throughout the world has led to specialization in biological fields, creating a conducive situation for researchers interested in this subject. The basics of parasitology lie in morphology, pathology, and with recent updates in molecular parasitology, the scope has extended further. The current review is to address the recent update in ophthalmic parasites with special reference to pathology and give a glimpse of further research in this field. PMID:27958200

  6. Microstrip antenna arrays with parasitic elements

    NASA Technical Reports Server (NTRS)

    Lee, Kai-Fong

    1996-01-01

    This research was concerned with using parasitic elements to improve the bandwidth, gain and axial ratio characteristics of microstrip antennas and arrays. Significant improvements in these characteristics were obtained using stacked and coplanar parasitic elements. Details of the results are described in a total of 16 journal and 17 conference papers. These are listed in Section four of this report.

  7. Parasites in terrestrial, freshwater and marine systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Parasites are ubiquitous and diverse members of all biological communities. Macroparasites (worms and arthropods) and microparasites (viruses, bacteria and protozoans) have at least one life stage that must live on or in another species, or host, which is usually free-living. Parasites can have sub...

  8. Interactions of microfungi and plant parasitic nematodes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant parasitic nematodes and microfungi inhabit many of the same ecological habitats and interact in almost every conceivable way. Nematodes can feed on fungi, and conversely fungi can use nematodes as a food source. Fungi have been widely studied as biological controls of plant parasitic nematod...

  9. Zoonotic Parasites of Bobcats around Human Landscapes

    PubMed Central

    Scorza, Andrea V.; Bevins, Sarah N.; Riley, Seth P. D.; Crooks, Kevin R.; VandeWoude, Sue; Lappin, Michael R.

    2012-01-01

    We analyzed Lynx rufus fecal parasites from California and Colorado, hypothesizing that bobcats shed zoonotic parasites around human landscapes. Giardia duodenalis, Cryptosporidium, Ancylostoma, Uncinaria, and Toxocara cati were shed. Toxoplasma gondii serology demonstrated exposure. Giardia and Cryptosporidium shedding increased near large human populations. Genotyped Giardia may indicate indirect transmission with humans. PMID:22718941

  10. Blood parasites from California ducks and geese

    USGS Publications Warehouse

    Herman, C.M.

    1951-01-01

    Blood smears were procured from 1,011 geese and ducks of 19 species from various locations in California. Parasites were found in 28 individuals. The parasites observed included Haemoproteus hermani, Leucocytozoon simondi, microfilaria, Plasmodium relictum (=P. biziurae), and Plasmodium sp. with elongate gametocytes. This is the first report of a natural infection with a Plasmodium in North American wild ducks.

  11. From Fossil Parasitoids to Vectors: Insects as Parasites and Hosts.

    PubMed

    Nagler, Christina; Haug, Joachim T

    2015-01-01

    Within Metazoa, it has been proposed that as many as two-thirds of all species are parasitic. This propensity towards parasitism is also reflected within insects, where several lineages independently evolved a parasitic lifestyle. Parasitic behaviour ranges from parasitic habits in the strict sense, but also includes parasitoid, phoretic or kleptoparasitic behaviour. Numerous insects are also the host for other parasitic insects or metazoans. Insects can also serve as vectors for numerous metazoan, protistan, bacterial and viral diseases. The fossil record can report this behaviour with direct (parasite associated with its host) or indirect evidence (insect with parasitic larva, isolated parasitic insect, pathological changes of host). The high abundance of parasitism in the fossil record of insects can reveal important aspects of parasitic lifestyles in various evolutionary lineages. For a comprehensive view on fossil parasitic insects, we discuss here different aspects, including phylogenetic systematics, functional morphology and a direct comparison of fossil and extant species.

  12. Trichinella spiralis: the evolution of adaptation and parasitism

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  13. Parasites can enhance infections of fish with bacterial pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In aquaculture systems, fish are commonly infected by multiple pathogens, including parasites. Parasite Ichthyophthirius multifiliis (Ich) and bacterium Edwardsiella ictaluri are two common pathogens of cultured channel catfish. The objectives were to 1) evaluate the susceptibility of Ich parasitize...

  14. PARASITES AND POVERTY: THE CASE OF SCHISTOSOMIASIS

    PubMed Central

    King, Charles H.

    2009-01-01

    Simultaneous and sequential transmission of multiple parasites, and their resultant overlapping chronic infections, are facts of life in many underdeveloped rural areas. These represent significant but often poorly-measured health and economic burdens for affected populations. For example, the chronic inflammatory process associated with long-term schistosomiasis contributes to anaemia and undernutrition, which, in turn, can lead to growth stunting, poor school performance, poor work productivity, and continued poverty. To date, most national and international programs aimed at parasite control have not considered the varied economic and ecological factors underlying multi-parasite transmission, but some are beginning to provide a coordinated approach to control. In addition, interest is emerging in new studies for the re-evaluation and recalibration of the health burden of helminthic parasite infection. Their results should highlight the strong potential of integrated parasite control in efforts for poverty reduction. PMID:19962954

  15. Subversion of complement by hematophagous parasites

    PubMed Central

    Schroeder, Hélène; Skelly, Patrick; Zipfel, Peter F.; Losson, Bertrand; Vanderplasschen, Alain

    2008-01-01

    The complement system is a crucial part of innate and adaptive immunity which exerts a significant evolutionary pressure on pathogens. It has selected for those pathogens, mainly micro-organisms but also parasites, that have evolved countermeasures. The characterization of how pathogens evade complement attack is a rapidly developing field of current research. In recent years, multiple complement evasion strategies have been characterized. In this review, we focus on complement escape mechanisms expressed by hematophagous parasites, a heterogeneous group of metazoan parasites that share the property of ingesting the whole blood of their host. Complement inhibition is crucial for parasite survival within the host tissue or to facilitate blood feeding. Finally, complement inhibition by hematophagous parasites may also contribute to their success as pathogen vectors. PMID:18762211

  16. A description of parasites from Iranian snakes.

    PubMed

    Nasiri, Vahid; Mobedi, Iraj; Dalimi, Abdolhossein; Mirakabadi, Abbas Zare; Ghaffarifar, Fatemeh; Teymurzadeh, Shohreh; Karimi, Gholamreza; Abdoli, Amir; Paykari, Habibollah

    2014-12-01

    Little is known of the parasitic fauna of terrestrial snakes in Iran. This study aimed to evaluate the parasitic infection rates of snakes in Iran. A total of 87 snakes belonging to eight different species, that were collected between May 2012 and September 2012 and died after the hold in captivity, under which they were kept for taking poisons, were examined for the presence of gastrointestinal and blood parasites. According to our study 12 different genera of endoparasites in 64 (73.56%) of 87 examined snakes were determined. Forty one snakes (47.12%) had gastrointestinal parasites. In prepared blood smears, it was found that in 23 (26.43%) of 87 examined snakes there are at least one hemoparasite. To our knowledge, these are the first data on the internal parasitic fauna of Iranian terrestrial snakes and our findings show a higher prevalence of these organisms among them.

  17. Palaeoparasitology - Human Parasites in Ancient Material.

    PubMed

    Araújo, Adauto; Reinhard, Karl; Ferreira, Luiz Fernando

    2015-01-01

    Parasite finds in ancient material launched a new field of science: palaeoparasitology. Ever since the pioneering studies, parasites were identified in archaeological and palaeontological remains, some preserved for millions of years by fossilization. However, the palaeoparasitological record consists mainly of parasites found specifically in human archaeological material, preserved in ancient occupation sites, from prehistory until closer to 2015. The results include some helminth intestinal parasites still commonly found in 2015, such as Ascaris lumbricoides, Trichuris trichiura and hookworms, besides others such as Amoebidae and Giardia intestinalis, as well as viruses, bacteria, fungi and arthropods. These parasites as a whole provide important data on health, diet, climate and living conditions among ancient populations. This chapter describes the principal findings and their importance for knowledge on the origin and dispersal of infectious diseases.

  18. A novel method of rejection of brood parasitic eggs reduces parasitism intensity in a cowbird host

    PubMed Central

    De Mársico, María C.; Gloag, Ros; Ursino, Cynthia A.; Reboreda, Juan C.

    2013-01-01

    The hosts of brood parasitic birds are under strong selection pressure to recognize and remove foreign eggs from their nests, but parasite eggs may be too large to be grasped whole and too strong to be readily pierced by the host's bill. Such operating constraints on egg removal are proposed to force some hosts to accept parasite eggs, as the costs of deserting parasitized clutches can outweigh the cost of rearing parasites. By fitting microcameras inside nests, we reveal that the Neotropical baywing (Agelaioides badius), a host of the screaming cowbird (Molothrus rufoaxillaris) and shiny cowbird (Molothrus bonariensis), instead circumvents such constraints by kicking parasite eggs out of the nest. To our knowledge, this is the first report of a passerine bird using its feet to remove objects from the nest. Kick-ejection was an all-or-nothing response. Baywings kick-ejected parasite eggs laid before their own first egg and, if heavily parasitized, they ejected entire clutches and began again in the same nest. Few baywings were able to rid their nests of every parasite egg, but their novel ejection method allowed them to reduce the median parasitism intensity by 75 per cent (from four to one cowbird eggs per nest), providing an effective anti-parasite defence. PMID:23485877

  19. 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.

  20. Parasite remains in archaeological sites.

    PubMed

    Bouchet, Françoise; Guidon, Niéde; Dittmar, Katharina; Harter, Stephanie; Ferreira, Luiz Fernando; Chaves, Sergio Miranda; Reinhard, Karl; Araújo, Adauto

    2003-01-01

    Organic remains can be found in many different environments. They are the most significant source for paleoparasitological studies as well as for other paleoecological reconstruction. Preserved paleoparasitological remains are found from the driest to the moistest conditions. They help us to understand past and present diseases and therefore contribute to understanding the evolution of present human sociality, biology, and behavior. In this paper, the scope of the surviving evidence will be briefy surveyed, and the great variety of ways it has been preserved in different environments will be discussed. This is done to develop to the most appropriated techniques to recover remaining parasites. Different techniques applied to the study of paleoparasitological remains, preserved in different environments, are presented. The most common materials used to analyze prehistoric human groups are reviewed, and their potential for reconstructing ancient environment and disease are emphasized. This paper also urges increased cooperation among archaeologists, paleontologists, and paleoparasitologists.

  1. Parasite threat to panda conservation.

    PubMed

    Zhang, Jin-Shuo; Daszak, Peter; Huang, Hua-Li; Yang, Guang-You; Kilpatrick, A Marm; Zhang, Shuyi

    2008-03-01

    The giant panda is a global symbol of wildlife conservation that is threatened by historic and current habitat loss. Despite a great deal of research on the physiology, reproductive biology, and diet of pandas in the wild and in captivity, there is little information on wild panda mortality. Here we integrate previously unavailable data on the mortality of wild pandas. We report on three recent phases of panda mortality: deaths due to bamboo flowering in the 1970s and 1980s, surprisingly extensive poaching in the 1980s and 1990s, and a parasitic infection over the past few years. Our analyses suggest that the current most significant threat to wild panda survival is disease due to extraintestinal migration (visceral larval migrans) by an ascarid nematode. We demonstrate that the probability of death of wild pandas being caused by this disease increased significantly between 1971 and 2005 and discuss the possible factors leading to the emergence of this disease.

  2. The Berkeley parasitic SETI program

    NASA Technical Reports Server (NTRS)

    Bowyer, S.; Zeitlin, G.; Tarter, J.; Lampton, M.; Welch, W. J.

    1983-01-01

    Parasitic programs for the Search for Extraterrestrial Intelligence (SETI), carried out concurrently with conventional radio astronomical observing programs, can be an attractive and cost-effective means of exploring the large multidimensional search space intrinsic to this effort. A microprocessor-based automated SETI acquisition system is described which searches for, and records, spectra of narrowband signals in the IF band of an observatory receiver. Data taken with this system over 35 days at the Hat Creek Radio Observatory at 1612 MHz are discussed. Out of approximately 100,000 spectra processed during this period, 4000 were identified by the system as containing narrowband signals and were recorded. Subsequent analysis indicates that over 3900 of these are due to local RF contamination. The remainder are undergoing further investigation.

  3. Ecology of avian brood parasitism at an early interfacing of host and parasite populations

    USGS Publications Warehouse

    Wiley, J.W.

    1982-01-01

    The shiny cowbird (Molothrus bonariensis), a brood parasite, has recently spread into the Greater Antilles from South America via the Lesser Antilles. This species is a host generalist and upon reaching Puerto Rico exploited avian communities with no history of social parasitism. Forty-two percent of the resident non-raptorial land bird species were parasitized in mangrove habitat study areas. Cowbird parasitism affected hosts by (1) depressing nest success an average of 41 percent below non-parasitized nests, and (2) reducing host productivity. Parasitized hosts produced 12 percent fewer eggs and fledged 67 percent fewer of their own chicks than non-parasitized pairs. Growth rates of chicks of some host species were lower in parasitized nests compared with non-parasitized nests while growth of others was not affected by brood parasitism. Cowbird chick growth varied directly with host size; i.e., cowbird chicks grew faster and attained greater fledging weight and body size in nests of larger hosts. Factors important in shiny cowbird host selection were examined within the mangrove study community. Cowbirds did not parasitize avian species in proportion to their abundance. The cowbird breeding season coincided with that of its major hosts, which were high quality foster species, and did not extend into other periods even though nests of poor quality species were available. Food habits and egg size of cowbirds were similar to those of their hosts, suggesting that cowbirds choose hosts partly on the basis of this alignment. Cowbirds locate nests by cryptically watching activities of birds in likely habitat. Despite the recency of the cowbird's arrival in Puerto Rico, some nesting species have effective anti-parasite strategies, including alien egg rejection and nest guarding. Behavior effective in avoiding parasitism is similar to that used by certain birds in evading nest predators. It is suggested that anti-predator behavior is preadaptive to countering cowbird

  4. Chemical Factors in Development and Transmission of Human Parasites.

    DTIC Science & Technology

    PARASITES, *PREVENTIVE MEDICINE, *BIOCIDES, *REPELLENTS, HORMONES, TABLES(DATA), SCHISTOSOMA MANSONI , BRAZIL, PARASITIC DISEASES, DISEASE VECTORS, INSECT REPELLENTS, CHAGAS DISEASE, TRYPANOSOMA CRUZI.

  5. The Integration of Cellular and Humoral Responses to Protozoan Parasites.

    DTIC Science & Technology

    IMMUNOLOGY, *PARASITES, * LEISHMANIA , *PLASMODIUM, *PROTOZOA, ISRAEL, EXPERIMENTAL DATA, RATS, MICE, MALARIA, IMMUNITY, CELLS(BIOLOGY), SEROLOGY, CULTURES(BIOLOGY), PARASITIC DISEASES, SPLEEN, HYPERSENSITIVITY.

  6. Parasites in cultured and feral fish.

    PubMed

    Scholz, T

    1999-08-01

    Parasites, causing little apparent damage in feral fish populations, may become causative agents of diseases of great importance in farmed fish, leading to pathological changes, decrease of fitness or reduction of the market value of fish. Despite considerable progress in fish parasitology in the last decades, major gaps still exist in the knowledge of taxonomy, biology, epizootiology and control of fish parasites, including such 'evergreens' as the ciliate Ichthyophthirius multifiliis, a causative agent of white spot disease, or proliferative kidney disease (PKD), one of the most economically damaging diseases in the rainbow trout industry which causative agent remain enigmatic. Besides long-recognized parasites, other potentially severe pathogens have appeared quite recently such as amphizoic amoebae, causative agents of amoebic gill disease (AGD), the monogenean Gyrodactylus salaris which has destroyed salmon populations in Norway, or sea lice, in particular Lepeophtheirus salmonis that endanger marine salmonids in some areas. Recent spreading of some parasites throughout the world (e.g. the cestode Bothriocephalus acheilognathi) has been facilitated through insufficient veterinary control during import of fish. Control of many important parasitic diseases is still far from being satisfactory and further research is needed. Use of chemotherapy has limitations and new effective, but environmentally safe drugs should be developed. A very promising area of future research seems to be studies on immunity in parasitic infections, use of molecular technology in diagnostics and development of new vaccines against the most pathogenic parasites.

  7. Systems analysis of host-parasite interactions.

    PubMed

    Swann, Justine; Jamshidi, Neema; Lewis, Nathan E; Winzeler, Elizabeth A

    2015-01-01

    Parasitic diseases caused by protozoan pathogens lead to hundreds of thousands of deaths per year in addition to substantial suffering and socioeconomic decline for millions of people worldwide. The lack of effective vaccines coupled with the widespread emergence of drug-resistant parasites necessitates that the research community take an active role in understanding host-parasite infection biology in order to develop improved therapeutics. Recent advances in next-generation sequencing and the rapid development of publicly accessible genomic databases for many human pathogens have facilitated the application of systems biology to the study of host-parasite interactions. Over the past decade, these technologies have led to the discovery of many important biological processes governing parasitic disease. The integration and interpretation of high-throughput -omic data will undoubtedly generate extraordinary insight into host-parasite interaction networks essential to navigate the intricacies of these complex systems. As systems analysis continues to build the foundation for our understanding of host-parasite biology, this will provide the framework necessary to drive drug discovery research forward and accelerate the development of new antiparasitic therapies.

  8. 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.

  9. Evolution of plant parasitism among nematodes.

    PubMed

    Baldwin, J G; Nadler, S A; Adams, B J

    2004-01-01

    Despite extraordinary diversity of free-living species, a comparatively small fraction of nematodes are parasites of plants. These parasites represent at least three disparate clades in the nematode tree of life, as inferred from rRNA sequences. Plant parasites share functional similarities regarding feeding, but many similarities in feeding structures result from convergent evolution and have fundamentally different developmental origins. Although Tylenchida rRNA phylogenies are not fully resolved, they strongly support convergent evolution of sedentary endoparasitism and plant nurse cells in cyst and root-knot nematodes. This result has critical implications for using model systems and genomics to identify and characterize parasitism genes for representatives of this clade. Phylogenetic studies reveal that plant parasites have rich and complex evolutionary histories that involve multiple transitions to plant parasitism and the possible use of genes obtained by horizontal transfer from prokaryotes. Developing a fuller understanding of plant parasitism will require integrating more comprehensive and resolved phylogenies with appropriate choices of model organisms and comparative evolutionary methods.

  10. Blood parasites in reptiles imported to Germany.

    PubMed

    Halla, Ursula; Ursula, Halla; Korbel, Rüdiger; Rüdiger, Korbel; Mutschmann, Frank; Frank, Mutschmann; Rinder, Monika; Monika, Rinder

    2014-12-01

    Though international trade is increasing, the significance of imported reptiles as carriers of pathogens with relevance to animal and human health is largely unknown. Reptiles imported to Germany were therefore investigated for blood parasites using light microscopy, and the detected parasites were morphologically characterized. Four hundred ten reptiles belonging to 17 species originating from 11 Asian, South American and African countries were included. Parasites were detected in 117 (29%) of individual reptiles and in 12 species. Haemococcidea (Haemogregarina, Hepatozoon, Schellackia) were found in 84% of snakes (Python regius, Corallus caninus), 20% of lizards (Acanthocercus atricollis, Agama agama, Kinyongia fischeri, Gekko gecko) and 50% of turtles (Pelusios castaneus). Infections with Hematozoea (Plasmodium, Sauroplasma) were detected in 14% of lizards (Acanthocercus atricollis, Agama agama, Agama mwanzae, K. fischeri, Furcifer pardalis, Xenagama batillifera, Acanthosaura capra, Physignathus cocincinus), while those with Kinetoplastea (Trypanosoma) were found in 9% of snakes (Python regius, Corallus caninus) and 25 % of lizards (K. fischeri, Acanthosaura capra, G. gecko). Nematoda including filarial larvae parasitized in 10% of lizards (Agama agama, Agama mwanzae, K. fischeri, Fu. pardalis, Physignathus cocincinus). Light microscopy mostly allowed diagnosis of the parasites' genus, while species identification was not possible because of limited morphological characteristics available for parasitic developmental stages. The investigation revealed a high percentage of imported reptiles being carriers of parasites while possible vectors and pathogenicity are largely unknown so far. The spreading of haemoparasites thus represents an incalculable risk for pet reptiles, native herpetofauna and even human beings.

  11. Mechanisms of cellular invasion by intracellular parasites.

    PubMed

    Walker, Dawn M; Oghumu, Steve; Gupta, Gaurav; McGwire, Bradford S; Drew, Mark E; Satoskar, Abhay R

    2014-04-01

    Numerous disease-causing parasites must invade host cells in order to prosper. Collectively, such pathogens are responsible for a staggering amount of human sickness and death throughout the world. Leishmaniasis, Chagas disease, toxoplasmosis, and malaria are neglected diseases and therefore are linked to socio-economical and geographical factors, affecting well-over half the world's population. Such obligate intracellular parasites have co-evolved with humans to establish a complexity of specific molecular parasite-host cell interactions, forming the basis of the parasite's cellular tropism. They make use of such interactions to invade host cells as a means to migrate through various tissues, to evade the host immune system, and to undergo intracellular replication. These cellular migration and invasion events are absolutely essential for the completion of the lifecycles of these parasites and lead to their for disease pathogenesis. This review is an overview of the molecular mechanisms of protozoan parasite invasion of host cells and discussion of therapeutic strategies, which could be developed by targeting these invasion pathways. Specifically, we focus on four species of protozoan parasites Leishmania, Trypanosoma cruzi, Plasmodium, and Toxoplasma, which are responsible for significant morbidity and mortality.

  12. Parasitism and phenotypic change in colonial hosts.

    PubMed

    Hartikainen, Hanna; Fontes, Inês; Okamura, Beth

    2013-09-01

    Changes in host phenotype are often attributed to manipulation that enables parasites to complete trophic transmission cycles. We characterized changes in host phenotype in a colonial host–endoparasite system that lacks trophic transmission (the freshwater bryozoan Fredericella sultana and myxozoan parasite Tetracapsuloides bryosalmonae). We show that parasitism exerts opposing phenotypic effects at the colony and module levels. Thus, overt infection (the development of infectious spores in the host body cavity) was linked to a reduction in colony size and growth rate, while colony modules exhibited a form of gigantism. Larger modules may support larger parasite sacs and increase metabolite availability to the parasite. Host metabolic rates were lower in overtly infected relative to uninfected hosts that were not investing in propagule production. This suggests a role for direct resource competition and active parasite manipulation (castration) in driving the expression of the infected phenotype. The malformed offspring (statoblasts) of infected colonies had greatly reduced hatching success. Coupled with the severe reduction in statoblast production this suggests that vertical transmission is rare in overtly infected modules. We show that although the parasite can occasionally infect statoblasts during overt infections, no infections were detected in the surviving mature offspring, suggesting that during overt infections, horizontal transmission incurs a trade-off with vertical transmission.

  13. Impacts of parasitic plants on natural communities.

    PubMed

    Press, Malcolm C; Phoenix, Gareth K

    2005-06-01

    Parasitic plants have profound effects on the ecosystems in which they occur. They are represented by some 4000 species and can be found in most major biomes. They acquire some or all of their water, carbon and nutrients via the vascular tissue of the host's roots or shoots. Parasitism has major impacts on host growth, allometry and reproduction, which lead to changes in competitive balances between host and nonhost species and therefore affect community structure, vegetation zonation and population dynamics. Impacts on hosts may further affect herbivores, pollinators and seed vectors, and the behaviour and diversity of these is often closely linked to the presence and abundance of parasitic plants. Parasitic plants can therefore be considered as keystone species. Community impacts are mediated by the host range of the parasite (the diversity of species that can potentially act as hosts) and by their preference and selection of particular host species. Parasitic plants can also alter the physical environment around them--including soil water and nutrients, atmospheric CO2 and temperature--and so may also be considered as ecosystem engineers. Such impacts can have further consequences in altering the resource supply to and behaviour of other organisms within parasitic plant communities.

  14. Where are the parasites in food webs?

    PubMed Central

    2012-01-01

    This review explores some of the reasons why food webs seem to contain relatively few parasite species when compared to the full diversity of free living species in the system. At present, there are few coherent food web theories to guide scientific studies on parasites, and this review posits that the methods, directions and questions in the field of food web ecology are not always congruent with parasitological inquiry. For example, topological analysis (the primary tool in food web studies) focuses on only one of six important steps in trematode life cycles, each of which requires a stable community dynamic to evolve. In addition, these transmission strategies may also utilize pathways within the food web that are not considered in traditional food web investigations. It is asserted that more effort must be focused on parasite-centric models, and a central theme is that many different approaches will be required. One promising approach is the old energetic perspective, which considers energy as the critical resource for all organisms, and the currency of all food web interactions. From the parasitological point of view, energy can be used to characterize the roles of parasites at all levels in the food web, from individuals to populations to community. The literature on parasite energetics in food webs is very sparse, but the evidence suggests that parasite species richness is low in food webs because parasites are limited by the quantity of energy available to their unique lifestyles. PMID:23092160

  15. Parasite infracommunities of a specialized marine fish species in a compound community dominated by generalist parasites.

    PubMed

    Lanfranchi, A L; Rossin, M A; Timi, J T

    2009-12-01

    The structure and composition of parasite communities of Mullus argentinae were analysed under two alternative hypotheses in a sample of 75 specimens caught off Mar del Plata, Argentina (38 degrees 27'S, 57 degrees 90'W). The first, based on the dominance of trophically transmitted larval parasites of low host-specificity among fish species in the region, predicts that infracommunities will be random subsets of regionally available species. The second, based on previous studies on other mullids, predicts that infracommunities will be dominated by adult digeneans. The parasite fauna of goatfishes was mainly composed of endoparasites, with metacercariae of Prosorhynchus australis accounting for most individual parasites and greatly affecting infracommunity descriptors. Its importance was reinforced by the low number of trophically transmitted larval parasites. Both hypotheses were refuted; parasite communities were not dominated either by trophically transmitted larval parasites of low host-specificity or by adult digeneans. Prosorhynchus australis was the only species displaying any degree of phylogenetic specificity. Therefore, the influence of phylogenetic factors seems to exceed that of ecological ones in determining the observed structure of infracommunities. However, it is precisely host ecology that allows P. australis to become the determinant of infracommunity structure by constraining the acquisition of other parasites. Studies aiming to determine the relative importance of evolutionary and ecological processes as structuring forces of parasite communities should take into account not only the identity and specificity of their component parasites, but also their availability in the compound community.

  16. Potential Parasite Transmission in Multi-Host Networks Based on Parasite Sharing

    PubMed Central

    Pilosof, Shai; Morand, Serge; Krasnov, Boris R.; Nunn, Charles L.

    2015-01-01

    Epidemiological networks are commonly used to explore dynamics of parasite transmission among individuals in a population of a given host species. However, many parasites infect multiple host species, and thus multi-host networks may offer a better framework for investigating parasite dynamics. We investigated the factors that influence parasite sharing – and thus potential transmission pathways – among rodent hosts in Southeast Asia. We focused on differences between networks of a single host species and networks that involve multiple host species. In host-parasite networks, modularity (the extent to which the network is divided into subgroups of rodents that interact with similar parasites) was higher in the multi-species than in the single-species networks. This suggests that phylogeny affects patterns of parasite sharing, which was confirmed in analyses showing that it predicted affiliation of individuals to modules. We then constructed “potential transmission networks” based on the host-parasite networks, in which edges depict the similarity between a pair of individuals in the parasites they share. The centrality of individuals in these networks differed between multi- and single-species networks, with species identity and individual characteristics influencing their position in the networks. Simulations further revealed that parasite dynamics differed between multi- and single-species networks. We conclude that multi-host networks based on parasite sharing can provide new insights into the potential for transmission among hosts in an ecological community. In addition, the factors that determine the nature of parasite sharing (i.e. structure of the host-parasite network) may impact transmission patterns. PMID:25748947

  17. [Laboratory tests for parasitic diseases in Israel].

    PubMed

    Marva, Esther; Grossman, Tamar

    2010-09-01

    Microscopic examination is still considered the gold standard for the diagnosis of parasitic diseases. In many clinical laboratories in hospitals and in health maintenance organizations ("Kupot Holim"), an excellent microscopic identification of parasites is performed. Microscopic examinations using wet mount preparations are performed for the detection of protozoan trophozoites and helmintic ova or larvae. Specific concentration techniques, including flotation and sedimentation procedures are further performed for the diagnosis of parasitic diseases. However, microscopic examinations are time-consuming, non-sensitive and not always reliable. Furthermore, the diagnosis of certain infections is not always possible by searching for the parasites in host tissues or excreta since risky invasive techniques might be necessary to locate the parasites. Detection of antibodies can be very useful as an indication for infection with a specific parasite, especially in individuals with no exposure to the parasite prior to recent travel in a disease-endemic area. In addition to serology, there are other tests of high sensitivity which can be integrated with microscopy, such as antigen detection in stool and blood samples as well as the use of other molecular diagnosis methods. There are two main laboratories in Israel where parasitic diagnosis is available by integration of microscopy, serology, antigen detection and molecular methods: The Reference Laboratory for Parasitology in Jerusalem at the Central Laboratories of the Ministry of Health (MOH) and the Laboratory of Parasitology at Soroka University Medical Center, Beer Sheva (SOR). There are also two special diagnostic units, one responsible for the identification of toxopLasma: Reference Laboratory for Toxoplasmosis, Public Health Laboratory, Ministry of Health, Tel Aviv (Tox), and the other for the identification of Leishmaniasis: Kuvin Center, Faculty of Medicine, Hebrew University of Jerusalem (Kuv). This article

  18. 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

  19. Parasitic Infections in Hematopoietic Stem Cell Transplantation

    PubMed Central

    Jarque, Isidro; Salavert, Miguel; Pemán, Javier

    2016-01-01

    Parasitic infections are rarely documented in hematopoietic stem cell transplant recipients. However they may be responsible for fatal complications that are only diagnosed at autopsy. Increased awareness of the possibility of parasitic diseases both in autologous and allogeneic stem cell transplant patients is relevant not only for implementing preventive measures but also for performing an early diagnosis and starting appropriate therapy for these unrecognized but fatal infectious complications in hematopoietic transplant recipients. In this review, we will focus on parasitic diseases occurring in this population especially those with major clinical relevance including toxoplasmosis, American trypanosomiasis, leishmaniasis, malaria, and strongyloidiasis, among others, highlighting the diagnosis and management in hematopoietic transplant recipients. PMID:27413527

  20. Parasitic Cavities Losses in SPEAR-2

    SciTech Connect

    Sands, Matt

    2016-12-19

    In PEP the large number of particles in a bunch, together with the small bunch length, may cause grievous energy loss from the beam to parasitic modes in the accelerating cavities. I have recently tried to estimate the parasitic cavity in PEP, based on a paper of Keil and I have obtained the result that the loss to parasitic modes will be about 10 MeV per particle per revolution for a bunch length of about 10 cm. In this note, I bring together some of the considerations that might bear on an experimental investigation of the loss using SPEAR-2.

  1. Blood parasites of penguins: a critical review.

    PubMed

    Vanstreels, Ralph Eric Thijl; Braga, Érika Martins; Catão-Dias, José Luiz

    2016-07-01

    Blood parasites are considered some of the most significant pathogens for the conservation of penguins, due to the considerable morbidity and mortality they have been shown to produce in captive and wild populations of these birds. Parasites known to occur in the blood of penguins include haemosporidian protozoans (Plasmodium, Leucocytozoon, Haemoproteus), piroplamid protozoans (Babesia), kinetoplastid protozoans (Trypanosoma), spirochete bacteria (Borrelia) and nematode microfilariae. This review provides a critical and comprehensive assessment of the current knowledge on these parasites, providing an overview of their biology, host and geographic distribution, epidemiology, pathology and implications for public health and conservation.

  2. Blood parasites of Taiwan birds.

    PubMed

    Manwell, R D; Allen, C S; Kuntz, R E

    1976-11-01

    Blood films were examined from 1477 birds of Taiwan (193 species, 49 families). Haemoproteus Kruse was by far the commonest parasite, with Leucocytozoon Danilewski a not very close second. it is probable that some of the Haemoproteus infections represented new species, and 1 occurring in the Bamboo Partridge (Bambusicola thoracica sonorivox Gould) seemed characteristic enough to justify recognition as such; the name Haemoproteus bambusicolae sp. n. is proposed for this organism. Malaria was found in 77 birds, the greatest number of infections occurring in the Bamboo Partridge. Most of them were caused by Plasmodium juxtanucleare Versiani & Gomes, a pathogen of chickens, but a number were due to an undetermined species of Plasmodium. The Bamboo Partridge may be a reservoir host of the former. A few other identified species (P. rouxi Sergent & Sergent, P. hexamerium Huff, P. tenue Laveran & Mesnil) were seen, as well as some unidentified ones. Plasmodium tenue was seen in Garrulax canorus taewanus Swinhoe, a babbler: until now it was known only from the Pekin Robin (Leiothrix luteus Scopoli), also a babbler, in which we have found it extremely common. Sixty-four microfilarial infections were identified; they were especially frequent in the Button Quail (Turnix suscitator rostrata Swinhoe).

  3. Trypanosomatid parasites causing neglected diseases.

    PubMed

    Nussbaum, K; Honek, J; Cadmus, C M C v C; Efferth, T

    2010-01-01

    Parasitic diseases such as Kala azar (visceral leishmaniasis), Chagas disease human (American trypanosomiasis) and African sleeping sickness (African trypanosomiasis) are affecting more than 27 million people worldwide. They are categorized amongst the most important neglected diseases causing approximately 150,000 deaths annually. As no vaccination is available, treatment is solely dependent on chemotherapeutic drugs. This review provides a comprehensive insight into the treatment of Kala azar, Chagas disease and African sleeping sickness. In addition to established drugs, novel small molecule- based therapeutic approaches are discussed. Drugs currently used for the treatment of Kala azar include pentavalent antimonials, Amphotericin B, Miltefosine, and Paromomycin. Liposomal formulations such as AmBisome provide promising alternatives. Furthermore, antiproliferative compounds might open new avenues in Kala azar treatment. Regarding Chagas disease, chemotherapy is based on two drugs, Nifurtimox and Benznidazole. However, sequencing of T. cruzi genome in the year 2005 raises a hope for new drug targets. Proteases, sterols and sialic acids are potential promising drug targets. Suramin, Pentamidine, Melarsporol and Eflornithine are well-established drugs to treat African sleeping sickness. New treatment options include combination therapy of Eflornithine and Nifurtimox, a Chagas disease therapeutic.. However, all approved chemotherapeutic compounds for trypanosomatid diseases suffer from high toxicity. Further, increasing resistance limits their efficacy and compliance.

  4. Parasite specialization in a unique habitat: hummingbirds as reservoirs of generalist blood parasites of Andean birds.

    PubMed

    Moens, Michaël A J; Valkiūnas, Gediminas; Paca, Anahi; Bonaccorso, Elisa; Aguirre, Nikolay; Pérez-Tris, Javier

    2016-09-01

    Understanding how parasites fill their ecological niches requires information on the processes involved in the colonization and exploitation of unique host species. Switching to hosts with atypical attributes may favour generalists broadening their niches or may promote specialization and parasite diversification as the consequence. We analysed which blood parasites have successfully colonized hummingbirds, and how they have evolved to exploit such a unique habitat. We specifically asked (i) whether the assemblage of Haemoproteus parasites of hummingbirds is the result of single or multiple colonization events, (ii) to what extent these parasites are specialized in hummingbirds or shared with other birds and (iii) how hummingbirds contribute to sustain the populations of these parasites, in terms of both prevalence and infection intensity. We sampled 169 hummingbirds of 19 species along an elevation gradient in Southern Ecuador to analyse the host specificity, diversity and infection intensity of Haemoproteus by molecular and microscopy techniques. In addition, 736 birds of 112 species were analysed to explore whether hummingbird parasites are shared with other birds. Hummingbirds hosted a phylogenetically diverse assemblage of generalist Haemoproteus lineages shared with other host orders. Among these parasites, Haemoproteus witti stood out as the most generalized. Interestingly, we found that infection intensities of this parasite were extremely low in passerines (with no detectable gametocytes), but very high in hummingbirds, with many gametocytes seen. Moreover, infection intensities of H. witti were positively correlated with the prevalence across host species. Our results show that hummingbirds have been colonized by generalist Haemoproteus lineages on multiple occasions. However, one of these generalist parasites (H. witti) seems to be highly dependent on hummingbirds, which arise as the most relevant reservoirs in terms of both prevalence and

  5. It's a predator-eat-parasite world: how characteristics of predator, parasite and environment affect consumption.

    PubMed

    Orlofske, Sarah A; Jadin, Robert C; Johnson, Pieter T J

    2015-06-01

    Understanding the effects of predation on disease dynamics is increasingly important in light of the role ecological communities can play in host-parasite interactions. Surprisingly, however, few studies have characterized direct predation of parasites. Here we used an experimental approach to show that consumption of free-living parasite stages is highly context dependent, with significant influences of parasite size, predator size and foraging mode, as well as environmental condition. Among the four species of larval trematodes and two types of predators (fish and larval damselflies) studied here, parasites with larger infective stages (size >1,000 μm) were most vulnerable to predation by fish, while small-bodied fish and damselflies (size <10 mm) consumed the most infectious stages. Small parasite species (size approx. 500 μm) were less frequently consumed by both fish and larval damselflies. However, these results depended strongly on light availability; trials conducted in the dark led to significantly fewer parasites consumed overall, especially those with a size of <1,000 μm, emphasizing the importance of circadian shedding times of parasite free-living stages for predation risk. Intriguingly, active predation functioned to help limit fishes' infection by directly penetrating parasite species. Our results are consistent with established theory developed for predation on zooplankton that emphasizes the roles of body size, visibility and predation modes and further suggest that consumer-resource theory may provide a predictive framework for when predators should significantly influence parasite transmission. These results contribute to our understanding of transmission in natural systems, the role of predator-parasite links in food webs and the evolution of parasite morphology and behavior.

  6. Biological invasions and host-parasite coevolution: different coevolutionary trajectories along separate parasite invasion fronts.

    PubMed

    Feis, Marieke E; Goedknegt, M Anouk; Thieltges, David W; Buschbaum, Christian; Wegner, K Mathias

    2016-08-01

    Host-parasite coevolution has rarely been observed in natural systems. Its study often relies on microparasitic infections introducing a potential bias in the estimation of the evolutionary change of host and parasite traits. Using biological invasions as a tool to study host-parasite coevolution in nature can overcome these biases. We demonstrate this with a cross-infection experiment in the invasive macroparasite Mytilicola intestinalis and its bivalve host, the blue mussel Mytilus edulis. The invasion history of the parasite is well known for the southeastern North Sea and is characterised by two separate invasion fronts that reached opposite ends of the Wadden Sea (i.e. Texel, The Netherlands and Sylt, Germany) in a similar time frame. The species' natural history thus makes this invasion an ideal natural experiment to study host-parasite coevolution in nature. We infected hosts from Texel, Sylt and Kiel (Baltic Sea, where the parasite is absent) with parasites from Texel and Sylt, to form sympatric, allopatric and naïve infestation combinations, respectively. We measured infection rate, host condition and parasite growth to show that sympatric host-parasite combinations diverged in terms of pre- and post-infection traits within <100 generations since their introduction. Texel parasites were more infective and more efficient at exploiting the host's resources. Hosts on Texel, on the other hand, evolved resistance to infection, whereas hosts on Sylt may have evolved tolerance. This illustrates that different coevolutionary trajectories can evolve along separate invasion fronts of the parasite, highlighting the use of biological invasions in studies of host-parasite coevolution in nature.

  7. Parasitic diarrhea in normal and malnourished children.

    PubMed

    Gendrel, D; Treluyer, J M; Richard-Lenoble, D

    2003-04-01

    Diarrhea is only one of the many manifestations of intestinal parasites. Environmental influences are inescapable, regardless of an individual's state of health: in a highly endemic region, intestinal parasitic colonization is almost the rule. The clinical expression of the parasitoses, however, is largely determined by host defenses; and when they are weakened, parasitic diarrhea is frequent and severe. Protein-energy malnutrition is by far the most important cause of immune deficiency in developing countries. Diarrhea caused by Strongyloides or Giardia is common and severe in malnourished children, while well-nourished children remain healthy carriers. These parasites require specific treatment in the malnourished; and the well-nourished should have preventive treatment when they are to receive corticosteroids or immunosuppressive agents. Diarrhea caused by Cryptosporidium spp. may be severe in malnourished or immunodeficient children, and recovery is achieved only after renutrition or treatment of the immunodeficiency.

  8. 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.

  9. Climate influences parasite-mediated competitive release.

    PubMed

    Larsen, Martin H; Jensen, K Thomas; Mouritsen, Kim N

    2011-09-01

    Parasitism is believed to play an important role in maintaining species diversity, for instance by facilitating coexistence between competing host species. However, the possibility that environmental factors may govern the outcome of parasite-mediated competition has rarely been considered. The closely related amphipods Corophium volutator and Corophium arenarium both serve as second intermediate host for detrimental trematodes. Corophium volutator is the superior competitor of the two, but also suffers from higher mortality when exposed to infective trematode stages. Here, we report parasite-mediated competitive release of C. arenarium in an intertidal habitat, in part triggered by unusually high temperatures linked to the North Atlantic climate oscillation (NAO). The elevated temperatures accelerated the transmission of cercariae from sympatric first intermediate hosts (mud snails) to amphipods, causing a local collapse of the parasite-sensitive C. volutator population and concordant increase in the abundance of the competitively inferior C. arenarium.

  10. Drug repurposing and human parasitic protozoan diseases

    PubMed Central

    Andrews, Katherine T.; Fisher, Gillian; Skinner-Adams, Tina S.

    2014-01-01

    Parasitic diseases have an enormous health, social and economic impact and are a particular problem in tropical regions of the world. Diseases caused by protozoa and helminths, such as malaria and schistosomiasis, are the cause of most parasite related morbidity and mortality, with an estimated 1.1 million combined deaths annually. The global burden of these diseases is exacerbated by the lack of licensed vaccines, making safe and effective drugs vital to their prevention and treatment. Unfortunately, where drugs are available, their usefulness is being increasingly threatened by parasite drug resistance. The need for new drugs drives antiparasitic drug discovery research globally and requires a range of innovative strategies to ensure a sustainable pipeline of lead compounds. In this review we discuss one of these approaches, drug repurposing or repositioning, with a focus on major human parasitic protozoan diseases such as malaria, trypanosomiasis, toxoplasmosis, cryptosporidiosis and leishmaniasis. PMID:25057459

  11. DEVELOPMENT OF APTAMERS TO WATERBORNE PARASITES

    EPA Science Inventory

    The Safe Drinking Water Act Amendment of 1996 mandates that the U. S. Environmental Protection Agency (EPA) evaluate public health risks associated with drinking water contaminants to include waterborne parasites, such as Cryptosporidium and Giardia. Additionally, the Agency est...

  12. Chapter 42. Waterborne and Foodborne Parasites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter identifies the most prominent parasites in North America that are acquired through contaminated food and water including protozoa (Acanthamoeba, Naegleria, Entamoeba, Giardia, Cryptosporidium, Cystoisospora, Cyclospora, Toxoplasma, and Balantidium), nematodes (Trichinella, Angiostrongyl...

  13. A productivity model for parasitized, multibrooded songbirds

    USGS Publications Warehouse

    Powell, L.A.; Knutson, M.G.

    2006-01-01

    We present an enhancement of a simulation model to predict annual productivity for Wood Thrushes (Hylocichla mustelina) and American Redstarts (Setophaga ruticilla); the model includes effects of Brown-headed Cowbird (Molothrus ater) parasitism. We used species-specific data from the Driftless Area Ecoregion of Wisconsin, Minnesota, and Iowa to parameterize the model as a case study. The simulation model predicted annual productivity of 2.03 ?? 1.60 SD for Wood Thrushes and 1.56 ?? 1.31 SD for American Redstarts. Our sensitivity analysis showed that high parasitism lowered Wood Thrush annual productivity more than American Redstart productivity, even though parasitism affected individual nests of redstarts more severely. Annual productivity predictions are valuable for habitat managers, but productivity is not easily obtained from field studies. Our model provides a useful means of integrating complex life history parameters to predict productivity for songbirds that experience nest parasitism. ?? The Cooper Ornithological Society 2006.

  14. Parasites of the Raccoon, Procyon lotor

    USGS Publications Warehouse

    Clark, G.M.; Herman, C.M.

    1959-01-01

    At least 76 species of parasites have been reported from raccoons. These include 4 species of protozoa, 27 nematodes, 20 trematodes, 7 cestodes, 3 acanthocephala, and 15 arthropods. In many cases these represent single reports. In other cases some of the parasites are known to be of frequent occurrence and broad geographical range on the basis of several surveys that have been conducted. During the past 30 years 260 raccoons have been examined for parasites at the Patuxent Research Refuge. While most of these animals were collected on the refuge, several were from other localities in Maryland and a few from outside this state. The known distribution and occurrence of parasites of the raccoon are presented on charts and representative specimens of some of those collected at the Patuxent Research Refuge are demonstrated.

  15. Regulation of Gene Expression in Protozoa Parasites

    PubMed Central

    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. PMID:20204171

  16. Travel/Travelers and Parasitic Diseases

    MedlinePlus

    ... Can Be Acquired During Travel* Contaminated Food and Water More Common giardiasis cryptosporidiosis cyclosporiasis Less Common amebiasis ... Page last updated: July 28, 2016 Content source: Global Health - Division of Parasitic Diseases Email Recommend Tweet ...

  17. Soil transmitted parasites in Qualyobia Governorate.

    PubMed

    El Fakahany, Amany F; Younis, Mohamed S; Ali, Ali El-Said; El-Ghareeb, Azza S; Omar, Rabab El Sayed

    2013-08-01

    The study determined the relation between prevalence of intestinal parasites and soil-transmitted parasites among households in Shiblanga representing a rural area of Qualyobia Governorate and Benha City representing an urban area of the same Governorate. The effect of soil's type on the intensity of parasites and to provide guidance on the prevention and control of soil transmitted parasitic infections for future studies in this field. This study was conducted at Benha City and Shiblanga village representing the urban and rural areas of Qualyobia Governorate. Geoparasites were investigated in-doors, around houses, in the fields and the streets from both areas. One hundred soil samples from Benha city and one hundred soil samples from Shiblanga village were collected .each hundred soil samples was collected in the form of: 25 samples from the fields, 25 samples in-indoor yards, 25 samples the streets, 25 samples around houses. Approximately 200 g soil was collected in plastic bags at 2-10 cm depth from different parts. Stool samples from households in same areas were collected after taken oral consent. All soil samples were screened for parasites using different parasitological methods (Zinc sulphate flotation, ether sédimentation technique, modified Baerman's apparatus and modified Berlese technique). All stool samples were examined using direct smear, formalinether concentration techniques for detection of helminthes eggs, and modified acid-fast staining for detection of protozoa. The results showed that 86/200 soil samples were contaminated with different parasites, the prevalence rate of 43%. Soil samples from Shiblanga village showed higher level of parasitic contamination (56%) and Benha city showed a lower level of contamination by different parasites (30%). Soil samples obtained from Manshiet El-Nour district, Benha revealed the highest level of parasitic contamination. While, in Shiblanga, El-Mansheya district revealed the highest level of parasitic

  18. LOG PERIODIC DIPOLE ARRAY WITH PARASITIC ELEMENTS

    DTIC Science & Technology

    The design and measured characteristics of dipole and monopole versions of a log periodic array with parasitic elements are discussed. In a dipole...for the elements to obtain log periodic performance of the anntenna. This design with parasitic elements lends itself to a monopole version of the...antenna which has a simplified feeding configuration. The result is a log periodic antenna design that can be used from high frequencies through microwave frequencies.

  19. 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

  20. Brood parasite eggs enhance egg survivorship in a multiply parasitized host

    PubMed Central

    Gloag, Ros; Fiorini, Vanina D.; Reboreda, Juan C.; Kacelnik, Alex

    2012-01-01

    Despite the costs to avian parents of rearing brood parasitic offspring, many species do not reject foreign eggs from their nests. We show that where multiple parasitism occurs, rejection itself can be costly, by increasing the risk of host egg loss during subsequent parasite attacks. Chalk-browed mockingbirds (Mimus saturninus) are heavily parasitized by shiny cowbirds (Molothrus bonariensis), which also puncture eggs in host nests. Mockingbirds struggle to prevent cowbirds puncturing and laying, but seldom remove cowbird eggs once laid. We filmed cowbird visits to nests with manipulated clutch compositions and found that mockingbird eggs were more likely to escape puncture the more cowbird eggs accompanied them in the clutch. A Monte Carlo simulation of this ‘dilution effect’, comparing virtual hosts that systematically either reject or accept parasite eggs, shows that acceptors enjoy higher egg survivorship than rejecters in host populations where multiple parasitism occurs. For mockingbirds or other hosts in which host nestlings fare well in parasitized broods, this benefit might be sufficient to offset the fitness cost of rearing parasite chicks, making egg acceptance evolutionarily stable. Thus, counterintuitively, high intensities of parasitism might decrease or even reverse selection pressure for host defence via egg rejection. PMID:22158956

  1. Eaten alive: cannibalism is enhanced by parasites

    PubMed Central

    Bunke, Mandy; Alexander, Mhairi E.; Dick, Jaimie T. A.; Hatcher, Melanie J.; Paterson, Rachel; Dunn, Alison M.

    2015-01-01

    Cannibalism is ubiquitous in nature and especially pervasive in consumers with stage-specific resource utilization in resource-limited environments. Cannibalism is thus influential in the structure and functioning of biological communities. Parasites are also pervasive in nature and, we hypothesize, might affect cannibalism since infection can alter host foraging behaviour. We investigated the effects of a common parasite, the microsporidian Pleistophora mulleri, on the cannibalism rate of its host, the freshwater amphipod Gammarus duebeni celticus. Parasitic infection increased the rate of cannibalism by adults towards uninfected juvenile conspecifics, as measured by adult functional responses, that is, the rate of resource uptake as a function of resource density. This may reflect the increased metabolic requirements of the host as driven by the parasite. Furthermore, when presented with a choice, uninfected adults preferred to cannibalize uninfected rather than infected juvenile conspecifics, probably reflecting selection pressure to avoid the risk of parasite acquisition. By contrast, infected adults were indiscriminate with respect to infection status of their victims, probably owing to metabolic costs of infection and the lack of risk as the cannibals were already infected. Thus parasitism, by enhancing cannibalism rates, may have previously unrecognized effects on stage structure and population dynamics for cannibalistic species and may also act as a selective pressure leading to changes in resource use. PMID:26064614

  2. Immune Escape Strategies of Malaria Parasites

    PubMed Central

    Gomes, Pollyanna S.; Bhardwaj, Jyoti; Rivera-Correa, Juan; Freire-De-Lima, Celio G.; Morrot, Alexandre

    2016-01-01

    Malaria is one of the most life-threatening infectious diseases worldwide. Immunity to malaria is slow and short-lived despite the repeated parasite exposure in endemic areas. Malaria parasites have evolved refined machinery to evade the immune system based on a range of genetic changes that include allelic variation, biomolecular exposure of proteins, and intracellular replication. All of these features increase the probability of survival in both mosquitoes and the vertebrate host. Plasmodium species escape from the first immunological trap in its invertebrate vector host, the Anopheles mosquitoes. The parasites have to pass through various immunological barriers within the mosquito such as anti-microbial molecules and the mosquito microbiota in order to achieve successful transmission to the vertebrate host. Within these hosts, Plasmodium species employ various immune evasion strategies during different life cycle stages. Parasite persistence against the vertebrate immune response depends on the balance among virulence factors, pathology, metabolic cost of the host immune response, and the parasites ability to evade the immune response. In this review we discuss the strategies that Plasmodium parasites use to avoid the vertebrate host immune system and how they promote successful infection and transmission. PMID:27799922

  3. Role of cholesterol in parasitic infections

    PubMed Central

    Bansal, Devendra; Bhatti, Harinderpal Singh; Sehgal, Rakesh

    2005-01-01

    The requirement of cholesterol for internalization of eukaryotic pathogens like protozoa (Leishmaniasis, Malaria and Toxoplasmosis) and the exchange of cholesterol along with other metabolites during reproduction in Schistosomes (helminths) under variable circumstances are poorly understood. In patients infected with some other helminthes, alterations in the lipid profile have been observed. Also, the mechanisms involved in lipid changes especially in membrane proteins related to parasite infections remain uncertain. Present review of literature shows that parasites induce significant changes in lipid parameters, as has been shown in the in vitro study where substitution of serum by lipid/cholesterol in medium and in experimental models (in vivo). Thus changes in lipid profile occur in patients having active infections with most of the parasites. Membrane proteins are probably involved in such reactions. All parasites may be metabolising cholesterol, but the exact relationship with pathogenic mechanism is not clear. So far, studies suggest that there may be some factors or enzymes, which allow the parasite to breakup and consume lipid/cholesterol. Further studies are needed for better understanding of the mechanisms involved in vivo. The present review analysis the various studies till date and the role of cholesterol in pathogenesis of different parasitic infections. PMID:15882457

  4. Eaten alive: cannibalism is enhanced by parasites.

    PubMed

    Bunke, Mandy; Alexander, Mhairi E; Dick, Jaimie T A; Hatcher, Melanie J; Paterson, Rachel; Dunn, Alison M

    2015-03-01

    Cannibalism is ubiquitous in nature and especially pervasive in consumers with stage-specific resource utilization in resource-limited environments. Cannibalism is thus influential in the structure and functioning of biological communities. Parasites are also pervasive in nature and, we hypothesize, might affect cannibalism since infection can alter host foraging behaviour. We investigated the effects of a common parasite, the microsporidian Pleistophora mulleri, on the cannibalism rate of its host, the freshwater amphipod Gammarus duebeni celticus. Parasitic infection increased the rate of cannibalism by adults towards uninfected juvenile conspecifics, as measured by adult functional responses, that is, the rate of resource uptake as a function of resource density. This may reflect the increased metabolic requirements of the host as driven by the parasite. Furthermore, when presented with a choice, uninfected adults preferred to cannibalize uninfected rather than infected juvenile conspecifics, probably reflecting selection pressure to avoid the risk of parasite acquisition. By contrast, infected adults were indiscriminate with respect to infection status of their victims, probably owing to metabolic costs of infection and the lack of risk as the cannibals were already infected. Thus parasitism, by enhancing cannibalism rates, may have previously unrecognized effects on stage structure and population dynamics for cannibalistic species and may also act as a selective pressure leading to changes in resource use.

  5. Review of Parasitic Zoonoses in Egypt

    PubMed Central

    Youssef, Ahmed I.; Uga, Shoji

    2014-01-01

    This review presents a comprehensive picture of the zoonotic parasitic diseases in Egypt, with particular reference to their relative prevalence among humans, animal reservoirs of infection, and sources of human infection. A review of the available literature indicates that many parasitic zoonoses are endemic in Egypt. Intestinal infections of parasitic zoonoses are widespread and are the leading cause of diarrhea, particularly among children and residents of rural areas. Some parasitic zoonoses are confined to specific geographic areas in Egypt, such as cutaneous leishmaniasis and zoonotic babesiosis in the Sinai. Other areas have a past history of a certain parasitic zoonoses, such as visceral leishmaniasis in the El-Agamy area in Alexandria. As a result of the implementation of control programs, a marked decrease in the prevalence of other zoonoses, such as schistosomiasis and fascioliasis has been observed. Animal reservoirs of parasitic zoonoses have been identified in Egypt, especially in rodents, stray dogs and cats, as well as vectors, typically mosquitoes and ticks, which constitute potential risks for disease transmission. Prevention and control programs against sources and reservoirs of zoonoses should be planned by public health and veterinary officers based on reliable information from systematic surveillance. PMID:24808742

  6. Immune Escape Strategies of Malaria Parasites.

    PubMed

    Gomes, Pollyanna S; Bhardwaj, Jyoti; Rivera-Correa, Juan; Freire-De-Lima, Celio G; Morrot, Alexandre

    2016-01-01

    Malaria is one of the most life-threatening infectious diseases worldwide. Immunity to malaria is slow and short-lived despite the repeated parasite exposure in endemic areas. Malaria parasites have evolved refined machinery to evade the immune system based on a range of genetic changes that include allelic variation, biomolecular exposure of proteins, and intracellular replication. All of these features increase the probability of survival in both mosquitoes and the vertebrate host. Plasmodium species escape from the first immunological trap in its invertebrate vector host, the Anopheles mosquitoes. The parasites have to pass through various immunological barriers within the mosquito such as anti-microbial molecules and the mosquito microbiota in order to achieve successful transmission to the vertebrate host. Within these hosts, Plasmodium species employ various immune evasion strategies during different life cycle stages. Parasite persistence against the vertebrate immune response depends on the balance among virulence factors, pathology, metabolic cost of the host immune response, and the parasites ability to evade the immune response. In this review we discuss the strategies that Plasmodium parasites use to avoid the vertebrate host immune system and how they promote successful infection and transmission.

  7. Parasitic castration: the evolution and ecology of body snatchers

    USGS Publications Warehouse

    Lafferty, Kevin D.; Kuris, Armand M.

    2009-01-01

    Castration is a response to the tradeoff between consumption and longevity faced by parasites. Common parasitic castrators include larval trematodes in snails, and isopod and barnacle parasites of crustaceans. The infected host (with its many unique properties) is the extended phenotype of the parasitic castrator. Because an individual parasitic castrator can usurp all the reproductive energy from a host, and that energy is limited, intra- and interspecific competition among castrators is generally intense. These parasites can be abundant and can substantially depress host density. Host populations subject to high rates of parasitic castration appear to respond by maturing more rapidly.

  8. [Treatment of parasitic liver diseases].

    PubMed

    Lecuna, V

    1989-01-01

    Most of primary and secondary parasitic liver diseases, at present can be property treated with drugs. Venezuelan pharmaceutic market has some peculiarities that have determined the disappearance from the market of many drugs such as emetine, thiabendazole, quinacrine and niclosamide. Diloxanide never appeared. Venezuela has no commercial international treatises that protect international patents in the pharmaceutical area. In addition, government regulation of cost of drugs is very strict. This is particularly true with old drugs (such as emetine or quinacrine) which had such a low price that is non-commercial for the maker of the drug, usually a large transnational, and is withdrawn from the market. Flexibility of prices is quite easy for new antibiotics which are very expensive. Frequently small national companies import the drug from Italy and Japan which sell the drug independently from international treats. Such companies frequently produce the drug for the government social system, but are unreliable and also frequently they withdraw the drug a variable period of time. The government, through the Ministry of Public Health administer free treatment with drugs for malaria, tuberculosis and leprosy. The severe economic crisis of the country has severely impaired the preventive programs and there is an increase of malaria due to gold mining in the south of the country and falciparum chloroquine resistance and an increase of schistosomiasis in a previous free area. Also administration of drugs for malaria has been severely impaired, mainly for economic reasons. The establishment of a National Government Laboratory is an old (as far as 1946) political goal, but has remained in the political intention.(ABSTRACT TRUNCATED AT 250 WORDS)

  9. Developmental Stage of Parasites Influences the Structure of Fish-Parasite Networks

    PubMed Central

    Bellay, Sybelle; de Oliveira, Edson Fontes; Almeida-Neto, Mário; Lima Junior, Dilermando Pereira; Takemoto, Ricardo Massato; Luque, José Luis

    2013-01-01

    Specialized interactions tend to be more common in systems that require strong reciprocal adaptation between species, such as those observed between parasites and hosts. Parasites exhibit a high diversity of species and life history strategies, presenting host specificity which increases the complexity of these antagonistic systems. However, most studies are limited to the description of interactions between a few parasite and host species, which restricts our understanding of these systems as a whole. We investigated the effect of the developmental stage of the parasite on the structure of 30 metazoan fish-parasite networks, with an emphasis on the specificity of the interactions, connectance and modularity. We assessed the functional role of each species in modular networks and its interactions within and among the modules according to the developmental stage (larval and adult) and taxonomic group of the parasites. We observed that most parasite and host species perform a few interactions but that parasites at the larval stage tended to be generalists, increasing the network connectivity within and among modules. The parasite groups did not differ among each other in the number of interactions within and among the modules when considering only species at the larval stage. However, the same groups of adult individuals differed from each other in their interaction patterns, which were related to variations in the degree of host specificity at this stage. Our results show that the interaction pattern of fishes with parasites, such as acanthocephalans, cestodes, digeneans and nematodes, is more closely associated with their developmental stage than their phylogenetic history. This finding corroborates the hypothesis that the life history of parasites results in adaptations that cross phylogenetic boundaries. PMID:24124506

  10. Developmental stage of parasites influences the structure of fish-parasite networks.

    PubMed

    Bellay, Sybelle; de Oliveira, Edson Fontes; Almeida-Neto, Mário; Lima Junior, Dilermando Pereira; Takemoto, Ricardo Massato; Luque, José Luis

    2013-01-01

    Specialized interactions tend to be more common in systems that require strong reciprocal adaptation between species, such as those observed between parasites and hosts. Parasites exhibit a high diversity of species and life history strategies, presenting host specificity which increases the complexity of these antagonistic systems. However, most studies are limited to the description of interactions between a few parasite and host species, which restricts our understanding of these systems as a whole. We investigated the effect of the developmental stage of the parasite on the structure of 30 metazoan fish-parasite networks, with an emphasis on the specificity of the interactions, connectance and modularity. We assessed the functional role of each species in modular networks and its interactions within and among the modules according to the developmental stage (larval and adult) and taxonomic group of the parasites. We observed that most parasite and host species perform a few interactions but that parasites at the larval stage tended to be generalists, increasing the network connectivity within and among modules. The parasite groups did not differ among each other in the number of interactions within and among the modules when considering only species at the larval stage. However, the same groups of adult individuals differed from each other in their interaction patterns, which were related to variations in the degree of host specificity at this stage. Our results show that the interaction pattern of fishes with parasites, such as acanthocephalans, cestodes, digeneans and nematodes, is more closely associated with their developmental stage than their phylogenetic history. This finding corroborates the hypothesis that the life history of parasites results in adaptations that cross phylogenetic boundaries.

  11. Zoonotic foodborne parasites and their surveillance.

    PubMed

    Murrell, K D

    2013-08-01

    Humans suffer from several foodborne helminth zoonotic diseases, some of which can be deadly (e.g., trichinellosis, cerebral cysticercosis) while others are chronic and cause only mild illness (e.g., intestinal taeniosis). The route of infection is normally consumption of the parasite's natural host as a human food item (e.g., meat). The risk for infection with these parasites is highest wherever people have an inadequate knowledge of infection and hygiene, poor animal husbandry practices, and unsafe management and disposal of human and animal waste products. The design of surveillance and control strategies for the various foodborne parasite species, and the involvement of veterinary and public health agencies, vary considerably because of the different life cycles of these parasites, and epidemiological features. Trichinella spiralis, which causes most human trichinellosis, is acquired from the consumption of pork, although increasingly cases occur from eating wild game. For cysticercosis, however, the only sources for human infection are pork (Taenia solium) or beef (T. saginata). The chief risk factor for infection of humans with these parasites is the consumption of meat that has been inadequately prepared. For the pig or cow, however, the risk factors are quite different between Trichinella and Taenia. For T. spiralis the major source of infection of pigs is exposure to infected animal meat (which carries the infective larval stage), while for both Taenia species it is human faecal material contaminated with parasite eggs shed by the adult intestinal stage of the tapeworm. Consequently, the means for preventing exposure of pigs and cattle to infective stages of T. spiralis, T. solium, and T. saginata vary markedly, especially the requirements for ensuring the biosecurity of these animals at the farm. The surveillance strategies and methods required for these parasites in livestock are discussed, including the required policy-level actions and the necessary

  12. Host-parasite interactions that guide red blood cell invasion by malaria parasites

    PubMed Central

    Paul, Aditya S.; Egan, Elizabeth S.; Duraisingh, Manoj T.

    2015-01-01

    Purpose of Review Malaria is caused by the infection and proliferation of parasites from the genus Plasmodium in red blood cells (RBCs). A free Plasmodium parasite, or merozoite, released from an infected RBC must invade another RBC host cell to sustain a blood-stage infection. Here, we review recent advances on RBC invasion by Plasmodium merozoites, focusing on specific molecular interactions between host and parasite. Recent findings Recent work highlights the central role of host-parasite interactions at virtually every stage of RBC invasion by merozoites. Biophysical experiments have for the first time measured the strength of merozoite-RBC attachment during invasion. For P. falciparum, there have been many key insights regarding the invasion ligand PfRh5 in particular, including its influence on host species tropism, a co-crystal structure with its RBC receptor basigin, and its suitability as a vaccine target. For P. vivax, researchers identified the origin and emergence of the parasite from Africa, demonstrating a natural link to the Duffy-negative RBC variant in African populations. For the simian parasite P. knowlesi, zoonotic invasion into human cells is linked to RBC age, which has implications for parasitemia during an infection and thus malaria. Summary New studies of the molecular and cellular mechanisms governing RBC invasion by Plasmodium parasites have shed light on various aspects of parasite biology and host cell tropism; and indicate opportunities for malaria control. PMID:25767956

  13. Interactions among co-infecting parasite species: a mechanism maintaining genetic variation in parasites?

    PubMed

    Seppälä, Otto; Karvonen, Anssi; Valtonen, E Tellervo; Jokela, Jukka

    2009-02-22

    Individuals of free-living organisms are often infected simultaneously by a community of parasites. If the co-infecting parasites interact, then this can add significantly to the diversity of host genotypexparasite genotype interactions. However, interactions between parasite species are usually not examined considering potential variation in interactions between different strain combinations of co-infecting parasites. Here, we examined the importance of interactions between strains of fish eye flukes Diplostomum spathaceum and Diplostomum gasterostei on their infectivity in naive fish hosts. We assessed the infection success of strains of both species in single-strain exposures and in co-exposures with a random strain of the other species. Parasite infection success did not consistently increase or decrease in the co-exposure treatment, but depended on the combinations of co-infecting parasite strains. This disrupted the relative infectivity of D. spathaceum strains observed in single-strain exposures. The infection success of D. gasterostei strains was independent of exposure type. These results suggest that interactions among parasite species may be strain specific and potentially promote maintenance of genetic polymorphism in parasite populations.

  14. Host-Parasite Interaction: Parasite-Derived and -Induced Proteases That Degrade Human Extracellular Matrix

    PubMed Central

    Piña-Vázquez, Carolina; Reyes-López, Magda; Ortíz-Estrada, Guillermo; de la Garza, Mireya; Serrano-Luna, Jesús

    2012-01-01

    Parasitic protozoa are among the most important pathogens worldwide. Diseases such as malaria, leishmaniasis, amoebiasis, giardiasis, trichomoniasis, and trypanosomiasis affect millions of people. Humans are constantly threatened by infections caused by these pathogens. Parasites engage a plethora of surface and secreted molecules to attach to and enter mammalian cells. The secretion of lytic enzymes by parasites into host organs mediates critical interactions because of the invasion and destruction of interstitial tissues, enabling parasite migration to other sites within the hosts. Extracellular matrix is a complex, cross-linked structure that holds cells together in an organized assembly and that forms the basement membrane lining (basal lamina). The extracellular matrix represents a major barrier to parasites. Therefore, the evolution of mechanisms for connective-tissue degradation may be of great importance for parasite survival. Recent advances have been achieved in our understanding of the biochemistry and molecular biology of proteases from parasitic protozoa. The focus of this paper is to discuss the role of protozoan parasitic proteases in the degradation of host ECM proteins and the participation of these molecules as virulence factors. We divide the paper into two sections, extracellular and intracellular protozoa. PMID:22792442

  15. Fishing out marine parasites? Impacts of fishing on rates of parasitism in the ocean

    USGS Publications Warehouse

    Wood, Chelsea L.; Lafferty, Kevin D.; Micheli, Fiorenza

    2010-01-01

    Among anthropogenic effects on the ocean, fishing is one of the most pervasive and extends deepest into the past. Because fishing reduces the density of fish (reducing transmission efficiency of directly transmitted parasites), selectively removes large fish (which tend to carry more parasites than small fish), and reduces food web complexity (reducing transmission efficiency of trophically transmitted parasites), the removal of fish from the world’s oceans over the course of hundreds of years may be driving a long-term, global decline in fish parasites. There has been growing recognition in recent years that parasites are a critical part of biodiversity and that their loss could substantially alter ecosystem function. Such a loss may be among the last major ecological effects of industrial fishing to be recognized by scientists.

  16. Canonical and variant histones of protozoan parasites.

    PubMed

    Dalmasso, Maria Carolina; Sullivan, William Joseph; Angel, Sergio Oscar

    2011-06-01

    Protozoan parasites have tremendously diverse lifestyles that require adaptation to a remarkable assortment of different environmental conditions. In order to complete their life cycles, protozoan parasites rely on fine-tuning gene expression. In general, protozoa use novel regulatory elements, transcription factors, and epigenetic mechanisms to regulate their transcriptomes. One of the most surprising findings includes the nature of their histones--these primitive eukaryotes lack some histones yet harbor novel histone variants of unknown function. In this review, we describe the histone components of different protozoan parasites based on literature and database searching. We summarize the key discoveries regarding histones and histone variants and their impact on chromatin regulation in protozoan parasites. In addition, we list histone genes IDs, sequences, and genomic localization of several protozoan parasites and Microsporidia histones, obtained from a thorough search of genome databases. We then compare these findings with those observed in higher eukaryotes, allowing us to highlight some novel aspects of epigenetic regulation in protists and to propose questions to be addressed in the upcoming years.

  17. The comparative ecology and biogeography of parasites

    PubMed Central

    Poulin, Robert; Krasnov, Boris R.; Mouillot, David; Thieltges, David W.

    2011-01-01

    Comparative ecology uses interspecific relationships among traits, while accounting for the phylogenetic non-independence of species, to uncover general evolutionary processes. Applied to biogeographic questions, it can be a powerful tool to explain the spatial distribution of organisms. Here, we review how comparative methods can elucidate biogeographic patterns and processes, using analyses of distributional data on parasites (fleas and helminths) as case studies. Methods exist to detect phylogenetic signals, i.e. the degree of phylogenetic dependence of a given character, and either to control for these signals in statistical analyses of interspecific data, or to measure their contribution to variance. Parasite–host interactions present a special case, as a given trait may be a parasite trait, a host trait or a property of the coevolved association rather than of one participant only. For some analyses, it is therefore necessary to correct simultaneously for both parasite phylogeny and host phylogeny, or to evaluate which has the greatest influence on trait expression. Using comparative approaches, we show that two fundamental properties of parasites, their niche breadth, i.e. host specificity, and the nature of their life cycle, can explain interspecific and latitudinal variation in the sizes of their geographical ranges, or rates of distance decay in the similarity of parasite communities. These findings illustrate the ways in which phylogenetically based comparative methods can contribute to biogeographic research. PMID:21768153

  18. Codon optimization underpins generalist parasitism in fungi

    PubMed Central

    Badet, Thomas; Peyraud, Remi; Mbengue, Malick; Navaud, Olivier; Derbyshire, Mark; Oliver, Richard P; Barbacci, Adelin; Raffaele, Sylvain

    2017-01-01

    The range of hosts that parasites can infect is a key determinant of the emergence and spread of disease. Yet, the impact of host range variation on the evolution of parasite genomes remains unknown. Here, we show that codon optimization underlies genome adaptation in broad host range parasites. We found that the longer proteins encoded by broad host range fungi likely increase natural selection on codon optimization in these species. Accordingly, codon optimization correlates with host range across the fungal kingdom. At the species level, biased patterns of synonymous substitutions underpin increased codon optimization in a generalist but not a specialist fungal pathogen. Virulence genes were consistently enriched in highly codon-optimized genes of generalist but not specialist species. We conclude that codon optimization is related to the capacity of parasites to colonize multiple hosts. Our results link genome evolution and translational regulation to the long-term persistence of generalist parasitism. DOI: http://dx.doi.org/10.7554/eLife.22472.001 PMID:28157073

  19. Fighting fish parasites with photodynamically active chlorophyllin.

    PubMed

    Häder, D-P; Schmidl, J; Hilbig, R; Oberle, M; Wedekind, H; Richter, P

    2016-06-01

    Water-soluble chlorophyll (chlorophyllin) was used in a phototoxic reaction against a number of fish ectoparasites such as Ichtyobodo, Dactylogyrus, Trichodina, and Argulus. Chlorophyllin is applied to the water at concentrations of several micrograms per milliliter for a predefined incubation time, and afterwards, the parasites are exposed to simulated solar radiation. Application in the dark caused only little damage to the parasites; likewise, light exposure without the addition of the photosensitizer was ineffective. In Ichthyobodo, 2 μg/mL proved sufficient with subsequent simulated solar radiation to almost quantitatively kill the parasites, while in Dactylogyrus, a concentration of about 6 μg/mL was necessary. The LD50 value for this parasite was 1.02 μg/mL. Trichodina could be almost completely eliminated at 2 μg/mL. Only in the parasitic crustacean Argulus, no killing could be achieved by a photodynamic reaction using chlorophyllin. Chlorophyllin is non-toxic, biodegradable, and can be produced at low cost. Therefore, we propose that chlorophyllin (or other photodynamic substances) are a possible effective countermeasure against several ectoparasites in ponds and aquaculture since chemical remedies are either forbidden and/or ineffective.

  20. Parasitic diarrheal disease: drug development and targets

    PubMed Central

    Azam, Amir; Peerzada, Mudasir N.; Ahmad, Kamal

    2015-01-01

    Diarrhea is the manifestation of gastrointestinal infection and is one of the major causes of mortality and morbidity specifically among the children of less than 5 years age worldwide. Moreover, in recent years there has been a rise in the number of reports of intestinal infections continuously in the industrialized world. These are largely related to waterborne and food borne outbreaks. These occur by the pathogenesis of both prokaryotic and eukaryotic organisms like bacteria and parasites. The parasitic intestinal infection has remained mostly unexplored and under assessed in terms of therapeutic development. The lack of new drugs and the risk of resistance have led us to carry out this review on drug development for parasitic diarrheal diseases. The major focus has been depicted on commercially available drugs, currently synthesized active heterocyclic compounds and unique drug targets, that are vital for the existence and growth of the parasites and can be further exploited for the search of therapeutically active anti-parasitic agents. PMID:26617574

  1. Flagellar motility in eukaryotic human parasites.

    PubMed

    Krüger, Timothy; Engstler, Markus

    2015-10-01

    A huge variety of protists rely on one or more motile flagella to either move themselves or move fluids and substances around them. Many of these flagellates have evolved a symbiotic or parasitic lifestyle. Several of the parasites have adapted to human hosts, and include agents of prevalent and serious diseases. These unicellular parasites have become specialised in colonising a wide range of biological niches within humans. They usually have diverse transmission cycles, and frequently manifest a variety of distinct morphological stages. The motility of the single or multiple flagella plays important but understudied roles in parasite transmission, host invasion, dispersal, survival, proliferation and pathology. In this review we provide an overview of the important human pathogens that possess a motile flagellum for at least part of their life cycle. We highlight recently published studies that aim to elucidate motility mechanisms, and their relevance for human disease. We then bring the physics of swimming at the microscale into context, emphasising the importance of interdisciplinary approaches for a full understanding of flagellate motility - especially in light of the parasites' microenvironments and population dynamics. Finally, we summarise some important technological aspects, describing challenges for the field and possibilities for motility analyses in the future.

  2. Association between host's genetic diversity and parasite burden in damselflies.

    PubMed

    Kaunisto, K M; Viitaniemi, H M; Leder, E H; Suhonen, J

    2013-08-01

    Recent research indicates that low genetic variation in individuals can increase susceptibility to parasite infection, yet evidence from natural invertebrate populations remains scarce. Here, we studied the relationship between genetic heterozygosity, measured as AFLP-based inbreeding coefficient fAFLP , and gregarine parasite burden from eleven damselfly, Calopteryx splendens, populations. We found that in the studied populations, 5-92% of males were parasitized by endoparasitic gregarines (Apicomplexa: Actinocephalidae). Number of parasites ranged from none to 47 parasites per male, and parasites were highly aggregated in a few hosts. Mean individual fAFLP did not differ between populations. Moreover, we found a positive association between individual's inbreeding coefficient and parasite burden. In other words, the more homozygous the individual, the more parasites it harbours. Thus, parasites are likely to pose strong selection pressure against inbreeding and homozygosity. Our results support the heterozygosity-fitness correlation hypothesis, which suggests the importance of heterozygosity for an individual's pathogen resistance.

  3. Can host ecology and kin selection predict parasite virulence?

    PubMed

    Gleichsner, Alyssa M; Minchella, Dennis J

    2014-07-01

    Parasite virulence, or the damage a parasite does to its host, is measured in terms of both host costs (reductions in host growth, reproduction and survival) and parasite benefits (increased transmission and parasite numbers) in the literature. Much work has shown that ecological and genetic factors can be strong selective forces in virulence evolution. This review uses kin selection theory to explore how variations in host ecological parameters impact the genetic relatedness of parasite populations and thus virulence. We provide a broad overview of virulence and population genetics studies and then draw connections to existing knowledge about natural parasite populations. The impact of host movement (transporting parasites) and host resistance (filtering parasites) on the genetic structure and virulence of parasite populations is explored, and empirical studies of these factors using Plasmodium and trematode systems are proposed.

  4. Comparing mechanisms of host manipulation across host and parasite taxa

    USGS Publications Warehouse

    Lafferty, Kevin D.; Shaw, Jenny C.

    2013-01-01

    Parasites affect host behavior in several ways. They can alter activity, microhabitats or both. For trophically transmitted parasites (the focus of our study), decreased activity might impair the ability of hosts to respond to final-host predators, and increased activity and altered microhabitat choice might increase contact rates between hosts and final-host predators. In an analysis of trophically transmitted parasites, more parasite groups altered activity than altered microhabitat choice. Parasites that infected vertebrates were more likely to impair the host’s reaction to predators, whereas parasites that infected invertebrates were more likely to increase the host’s contact with predators. The site of infection might affect how parasites manipulate their hosts. For instance, parasites in the central nervous system seem particularly suited to manipulating host behavior. Manipulative parasites commonly occupy the body cavity, muscles and central nervous systems of their hosts. Acanthocephalans in the data set differed from other taxa in that they occurred exclusively in the body cavity of invertebrates. In addition, they were more likely to alter microhabitat choice than activity. Parasites in the body cavity (across parasite types) were more likely to be associated with increased host contact with predators. Parasites can manipulate the host through energetic drain, but most parasites use more sophisticated means. For instance, parasites target four physiological systems that shape behavior in both invertebrates and vertebrates: neural, endocrine, neuromodulatory and immunomodulatory. The interconnections between these systems make it difficult to isolate specific mechanisms of host behavioral manipulation.

  5. Biological warfare: Microorganisms as drivers of host-parasite interactions.

    PubMed

    Dheilly, Nolwenn M; Poulin, Robert; Thomas, Frédéric

    2015-08-01

    Understanding parasite strategies for evasion, manipulation or exploitation of hosts is crucial for many fields, from ecology to medical sciences. Generally, research has focused on either the host response to parasitic infection, or the parasite virulence mechanisms. More recently, integrated studies of host-parasite interactions have allowed significant advances in theoretical and applied biology. However, these studies still provide a simplistic view of these as mere two-player interactions. Host and parasite are associated with a myriad of microorganisms that could benefit from the improved fitness of their partner. Illustrations of such complex multi-player interactions have emerged recently from studies performed in various taxa. In this conceptual article, we propose how these associated microorganisms may participate in the phenotypic alterations induced by parasites and hence in host-parasite interactions, from an ecological and evolutionary perspective. Host- and parasite-associated microorganisms may participate in the host-parasite interaction by interacting directly or indirectly with the other partner. As a result, parasites may develop (i) the disruptive strategy in which the parasite alters the host microbiota to its advantage, and (ii) the biological weapon strategy where the parasite-associated microorganism contributes to or modulates the parasite's virulence. Some phenotypic alterations induced by parasite may also arise from conflicts of interests between the host or parasite and its associated microorganism. For each situation, we review the literature and propose new directions for future research. Specifically, investigating the role of host- and parasite-associated microorganisms in host-parasite interactions at the individual, local and regional level will lead to a holistic understanding of how the co-evolution of the different partners influences how the other ones respond, both ecologically and evolutionary. The conceptual framework we

  6. Parasites and marine invasions: Ecological and evolutionary perspectives

    NASA Astrophysics Data System (ADS)

    Goedknegt, M. Anouk; Feis, Marieke E.; Wegner, K. Mathias; Luttikhuizen, Pieternella C.; Buschbaum, Christian; Camphuysen, Kees (C. J.); van der Meer, Jaap; Thieltges, David W.

    2016-07-01

    Worldwide, marine and coastal ecosystems are heavily invaded by introduced species and the potential role of parasites in the success and impact of marine invasions has been increasingly recognized. In this review, we link recent theoretical developments in invasion ecology with empirical studies from marine ecosystems in order to provide a conceptual framework for studying the role of parasites and their hosts in marine invasions. Based on an extensive literature search, we identified six mechanisms in which invaders directly or indirectly affect parasite and host populations and communities: I) invaders can lose some or all of their parasites during the invasion process (parasite release or reduction), often causing a competitive advantage over native species; II) invaders can also act as a host for native parasites, which may indirectly amplify the parasite load of native hosts (parasite spillback); III) invaders can also be parasites themselves and be introduced without needing co-introduction of the host (introduction of free-living infective stages); IV) alternatively, parasites may be introduced together with their hosts (parasite co-introduction with host); V) consequently, these co-introduced parasites can sometimes also infect native hosts (parasite spillover); and VI) invasive species may be neither a host nor a parasite, but nevertheless affect native parasite host interactions by interfering with parasite transmission (transmission interference). We discuss the ecological and evolutionary implications of each of these mechanisms and generally note several substantial effects on natural communities and ecosystems via i) mass mortalities of native populations creating strong selection gradients, ii) indirect changes in species interactions within communities and iii) trophic cascading and knock-on effects in food webs that may affect ecosystem function and services. Our review demonstrates a wide range of ecological and evolutionary implications of

  7. [Pseudo-parasites in histology and cytopathology].

    PubMed

    Pierre, C; Carloz, E; Marlier-Civatte, M; Branquet, D; Gros, P

    1995-01-01

    When interpreting smears and specimens, histologist and cytopathologists can be misled by images mimicking micro-organisms especially parasites such as protozoa, mycotic agents or helminths. Although some of these pitfalls are well-known, others can be problematic especially if nature of the contaminant is the same as that of the parasite that it mimics. False protozoa parasites can correspond either to exogenous agents such as spores, remnants of human cells, or inert exogenous particles. Pseudo-yeast images can be due to pollen, starch or soot but especially to cells such as macrophages, spermatozoids, and neurons or to various inert bodies such as pigments or calcifications. Pseudomycotic filaments can result from vegetable silk, asbestos bodies, radiate granules or fibrin. Curschmann's spirals and vegetable fibers can be confused with helminths and bacterial particles or pollen with helminth eggs.

  8. Host and parasite genomics, an Australasian perspective.

    PubMed

    Peacock, C

    2010-08-01

    The last decade has seen rapid advances in the genetic technology that is allowing researchers to examine host-pathogen interactions at a whole organism level. The advent of 'affordable' post-genomic technology has opened up a world of proteomic, transcriptomic and metabolomic methodologies that have been utilized by research groups in the Australasian region to examine the hosts' response to parasitic infections. Significant contributions have been made to many areas of parasitic infections with particular strengths being in malaria vaccine development, genetic susceptibility to leishmaniasis, genomic and proteomic analysis of schistosomiasis and genetic determination of resistance to helminthes in domestic animals. This review highlights some of these studies that have made significant contributions to our knowledge of the pathogenesis of parasitic diseases with a particular emphasis placed on studies reported in the last couple of years.

  9. Parasites as probes for prehistoric human migrations?

    PubMed

    Araujo, Adauto; Reinhard, Karl J; Ferreira, Luiz Fernando; Gardner, Scott L

    2008-03-01

    Host-specific parasites of humans are used to track ancient migrations. Based on archaeoparasitology, it is clear that humans entered the New World at least twice in ancient times. The archaeoparasitology of some intestinal parasites in the New World points to migration routes other than the Bering Land Bridge. Helminths have been found in mummies and coprolites in North and South America. Hookworms (Necator and Ancylostoma), whipworms (Trichuris trichiura) and other helminths require specific conditions for life-cycle completion. They could not survive in the cold climate of the northern region of the Americas. Therefore, humans would have lost some intestinal parasites while crossing Beringia. Evidence is provided here from published data of pre-Columbian sites for the peopling of the Americas through trans-oceanic or costal migrations.

  10. Wildlife parasites in a One Health world.

    PubMed

    Jenkins, Emily J; Simon, Audrey; Bachand, Nicholas; Stephen, Craig

    2015-05-01

    One Health has gained a remarkable profile in the animal and public health communities, in part owing to the pressing issues of emerging infectious diseases of wildlife origin. Wildlife parasitology can offer insights into One Health, and likewise One Health can provide justification to study and act on wildlife parasites. But how do we decide which wildlife parasites are One Health issues? We explore toxoplasmosis in wildlife in the Canadian Arctic as an example of a parasite that poses a risk to human health, and that also has potential to adversely affect wildlife populations of conservation concern and importance for food security and cultural well-being. This One Health framework can help communities, researchers, and policymakers prioritize issues for action in a resource-limited world.

  11. Horizontal gene transfer in parasitic plants.

    PubMed

    Davis, Charles C; Xi, Zhenxiang

    2015-08-01

    Horizontal gene transfer (HGT) between species has been a major focus of plant evolutionary research during the past decade. Parasitic plants, which establish a direct connection with their hosts, have provided excellent examples of how these transfers are facilitated via the intimacy of this symbiosis. In particular, phylogenetic studies from diverse clades indicate that parasitic plants represent a rich system for studying this phenomenon. Here, HGT has been shown to be astonishingly high in the mitochondrial genome, and appreciable in the nuclear genome. Although explicit tests remain to be performed, some transgenes have been hypothesized to be functional in their recipient species, thus providing a new perspective on the evolution of novelty in parasitic plants.

  12. Parasitic inhibition of cell death facilitates symbiosis.

    PubMed

    Pannebakker, Bart A; Loppin, Benjamin; Elemans, Coen P H; Humblot, Lionel; Vavre, Fabrice

    2007-01-02

    Symbiotic microorganisms have had a large impact on eukaryotic evolution, with effects ranging from parasitic to mutualistic. Mitochondria and chloroplasts are prime examples of symbiotic microorganisms that have become obligate for their hosts, allowing for a dramatic extension of suitable habitats for life. Out of the extraordinary diversity of bacterial endosymbionts in insects, most are facultative for their hosts, such as the ubiquitous Wolbachia, which manipulates host reproduction. Some endosymbionts, however, have become obligatory for host reproduction and/or survival. In the parasitoid wasp Asobara tabida the presence of Wolbachia is necessary for host oogenesis, but the mechanism involved is yet unknown. We show that Wolbachia influences programmed cell death processes (a host regulatory feature typically targeted by pathogens) in A. tabida, making its presence essential for the wasps' oocytes to mature. This suggests that parasite strategies, such as bacterial regulation of host apoptosis, can drive the evolution of host dependence, allowing for a swift transition from parasitism to mutualism.

  13. 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.

  14. The Plasmodium bottleneck: malaria parasite losses in the mosquito vector

    PubMed Central

    Smith, Ryan C; Vega-Rodríguez, Joel; Jacobs-Lorena, Marcelo

    2014-01-01

    Nearly one million people are killed every year by the malaria parasite Plasmodium. Although the disease-causing forms of the parasite exist only in the human blood, mosquitoes of the genus Anopheles are the obligate vector for transmission. Here, we review the parasite life cycle in the vector and highlight the human and mosquito contributions that limit malaria parasite development in the mosquito host. We address parasite killing in its mosquito host and bottlenecks in parasite numbers that might guide intervention strategies to prevent transmission. PMID:25185005

  15. Are there general laws in parasite ecology?

    PubMed

    Poulin, R

    2007-06-01

    As a scientific discipline matures, its theoretical underpinnings tend to consolidate around a few general laws that explain a wide range of phenomena, and from which can be derived further testable predictions. It is one of the goals of science to uncover the general principles that produce recurring patterns in nature. Although this has happened in many areas of physics and chemistry, ecology is yet to take this important step. Ecological systems are intrinsically complex, but this does not necessarily mean that everything about them is unpredictable or chaotic. Ecologists, whose grand aim is to understand the interactions that govern the distribution, abundance and diversity of living organisms at different scales, have uncovered several regular patterns, i.e. widely observable statistical tendencies, in the abundance or diversity of organisms in natural ecosystems. Some of these patterns, however, are contingent, i.e. they are only true under particular circumstances; nevertheless, the broad generality of many patterns hints at the existence of universal principles. What about parasite ecology: is it also characterized by recurring patterns and general principles? Evidence for repeatable empirical patterns in parasite ecology is reviewed here, in search of patterns that are consistently detectable across taxa or geographical areas. The coverage ranges from the population level all the way to large-scale patterns of parasite diversity and abundance (or biomass) and patterns in the structure of host-parasite interaction networks. Although general laws seem to apply to these extreme scales of studies, most patterns observed at the intermediate scale, i.e. the parasite community level, appear highly contingent and far from universal. The general laws uncovered to date are proving valuable, as they offer glimpses of the underlying processes shaping parasite ecology and diversity.

  16. Strength in numbers: high parasite burdens increase transmission of a protozoan parasite of monarch butterflies (Danaus plexippus).

    PubMed

    de Roode, Jacobus C; Chi, Jean; Rarick, Rachel M; Altizer, Sonia

    2009-08-01

    Parasites often produce large numbers of offspring within their hosts. High parasite burdens are thought to be important for parasite transmission, but can also lower host fitness. We studied the protozoan Ophryocystis elektroscirrha, a common parasite of monarch butterflies (Danaus plexippus), to quantify the benefits of high parasite burdens for parasite transmission. This parasite is transmitted vertically when females scatter spores onto eggs and host plant leaves during oviposition; spores can also be transmitted between mating adults. Monarch larvae were experimentally infected and emerging adult females were mated and monitored in individual outdoor field cages. We provided females with fresh host plant material daily and quantified their lifespan and lifetime fecundity. Parasite transmission was measured by counting the numbers of parasite spores transferred to eggs and host plant leaves. We also quantified spores transferred from infected females to their mating partners. Infected monarchs had shorter lifespans and lower lifetime fecundity than uninfected monarchs. Among infected females, those with higher parasite loads transmitted more parasite spores to their eggs and to host plant leaves. There was also a trend for females with greater parasite loads to transmit more spores to their mating partners. These results demonstrate that high parasite loads on infected butterflies confer a strong fitness advantage to the parasite by increasing between-host transmission.

  17. Parasitic diseases in humans transmitted by vectors.

    PubMed

    Cholewiński, Marcin; Derda, Monika; Hadaś, Edward

    2015-01-01

    Despite the considerable progress of medicine, parasitic diseases still pose a great threat to human health and life. Among parasitic diseases, those transmitted by vectors, mainly arthropods, play a particular role. These diseases occur most frequently in the poorest countries and affect a vast part of the human population. They include malaria, babesiosis, trypanosomiasis, leishmaniasis and filariasis. This study presents those vector-transmitted diseases that are responsible for the greatest incidence and mortality of people on a global scale. Attention is focused primarily on diseases transmitted by mosquitoes, flies, Hemiptera and ticks.

  18. Parasitic Infestation and Choice of Reproductive Regimes

    NASA Astrophysics Data System (ADS)

    Sousa, A. O.; de Oliveira, S. Moss; Sá Martins, J. S.

    The Penna model is used to simulate the competition between an asexual parthenogenetic and asexual population inhabiting the same environment represented by a square lattice. With a small probability, a newborn from the sexual population mutates into an asexual one and vice versa. Then, the asexual population rapidly dominates the sexual one, which all but disappears. However, when an infestation by mutating genetically coupled parasites, that mimic trematodes that feed on gonads, is introduced, the outcome may be one in which both populations coevolve or one in which one of the populations overcomes the other, depending on the density of parasites on the lattice.

  19. Zoonotic parasites from exotic meat in Malaysia.

    PubMed

    Fazly, Z A; Nurulaini, R; Shafarin, M S; Fariza, N J; Zawida, Z; Muhamad, H Y; Adnan, M; Premaalatha, B; Erwanas, A I; Zaini, C M; Ong, C C; Chandrawathani, P

    2013-09-01

    Four zoonotic parasites, Sarcocystis spp., Toxoplasma gondii, Trichinella spp. and Taenia spp were screened in exotic meats. A total of forty-six (n=46) meat samples from various species of exotic animals were received from all the 14 states in Malaysia from January 2012 to April 2012. All exotic meat samples were examined macroscopically and histologically for the four zoonotic parasites. Results by histological examination of exotic meats showed the presence of Sarcocystis and Toxoplasma cysts at 8.7% (n=4) and 4.3% (n=2) respectively. No Trichinella spp. and Taenia spp. were found.

  20. Non parasitic splenic cyst: a case report.

    PubMed

    Sarmast, Arif Hussain; Showkat, Hakim Irfan; Parray, Fazl Q; Lone, Rubina

    2012-01-01

    Primary splenic cyst is a rare entity and majority of the cases are classified as epithelial cysts. They are uncommon, comprising only about 10% of benign non-parasitic cysts. Most of the cysts are asymptomatic, and they are incidental findings during abdominal ultrasonography. We report a case of 20 years old male who presented with 1 year history of mild abdominal pain and left upper quadrant fullness. Ultrasound and computed tomography (CT) both were suggestive of splenic cyst. Serological tests were negative for parasitic infection. Splenectomy was done. Histopathological findings are consistent with splenic epithelial cyst.

  1. Cranberry Resistance to Dodder Parasitism: Induced Chemical Defenses and Behavior of a Parasitic Plant.

    PubMed

    Tjiurutue, Muvari Connie; Sandler, Hilary A; Kersch-Becker, Monica F; Theis, Nina; Adler, Lynn A

    2016-02-01

    Parasitic plants are common in many ecosystems, where they can structure community interactions and cause major economic damage. For example, parasitic dodder (Cuscuta spp.) can cause up to 80-100 % yield loss in heavily infested cranberry (Vaccinium macrocarpon) patches. Despite their ecological and economic importance, remarkably little is known about how parasitic plants affect, or are affected by, host chemistry. To examine chemically-mediated interactions between dodder and its cranberry host, we conducted a greenhouse experiment asking whether: (1) dodder performance varies with cranberry cultivar; (2) cultivars differ in levels of phytohormones, volatiles, or phenolics, and whether such variation correlates with dodder parasitism; (3) dodder parasitism induced changes in phytohormones, volatiles, or phenolics, and whether the level of inducible response varied among cultivars. We used five cranberry cultivars to assess host attractiveness to dodder and dodder performance. Dodder performance did not differ across cultivars, but there were marginally significant differences in host attractiveness to dodder, with fewer dodder attaching to Early Black than to any other cultivar. Dodder parasitism induced higher levels of salicylic acid (SA) across cultivars. Cultivars differed in overall levels of flavonols and volatile profiles, but not phenolic acids or proanthocyanidins, and dodder attachment induced changes in several flavonols and volatiles. While cultivars differed slightly in resistance to dodder attachment, we did not find evidence of chemical defenses that mediate these interactions. However, induction of several defenses indicates that parasitism alters traits that could influence subsequent interactions with other species, thus shaping community dynamics.

  2. Visualization of Malaria Parasites in the Skin Using the Luciferase Transgenic Parasite, Plasmodium berghei.

    PubMed

    Matsuoka, Hiroyuki; Tomita, Hiroyuki; Hattori, Ryuta; Arai, Meiji; Hirai, Makoto

    2015-03-01

    We produced a transgenic rodent malaria parasite (Plasmodium berghei) that contained the luciferase gene under a promoter region of elongation factor-1α. These transgenic (TG) parasites expressed luciferase in all stages of their life cycle, as previously reported. However, we were the first to succeed in observing sporozoites as a mass in mouse skin following their deposition by the probing of infective mosquitoes. Our transgenic parasites may have emitted stronger bioluminescence than previous TG parasites. The estimated number of injected sporozoites by mosquitoes was between 34 and 775 (median 80). Since luciferase activity diminished immediately after the death of the parasites, luciferase activity could be an indicator of the existence of live parasites. Our results indicated that sporozoites survived at the probed site for more than 42 hours. We also detected sporozoites in the liver within 15 min of the intravenous injection. Bioluminescence was not observed in the lung, kidney or spleen. We confirmed the observation that the liver was the first organ in which malaria parasites entered and increased in number.

  3. Northeast India Helminth Parasite Information Database (NEIHPID): Knowledge Base for Helminth Parasites

    PubMed Central

    Debnath, Manish; Kharumnuid, Graciously; Thongnibah, Welfrank; Tandon, Veena

    2016-01-01

    Most metazoan parasites that invade vertebrate hosts belong to three phyla: Platyhelminthes, Nematoda and Acanthocephala. Many of the parasitic members of these phyla are collectively known as helminths and are causative agents of many debilitating, deforming and lethal diseases of humans and animals. The North-East India Helminth Parasite Information Database (NEIHPID) project aimed to document and characterise the spectrum of helminth parasites in the north-eastern region of India, providing host, geographical distribution, diagnostic characters and image data. The morphology-based taxonomic data are supplemented with information on DNA sequences of nuclear, ribosomal and mitochondrial gene marker regions that aid in parasite identification. In addition, the database contains raw next generation sequencing (NGS) data for 3 foodborne trematode parasites, with more to follow. The database will also provide study material for students interested in parasite biology. Users can search the database at various taxonomic levels (phylum, class, order, superfamily, family, genus, and species), or by host, habitat and geographical location. Specimen collection locations are noted as co-ordinates in a MySQL database and can be viewed on Google maps, using Google Maps JavaScript API v3. The NEIHPID database has been made freely available at http://nepiac.nehu.ac.in/index.php PMID:27285615

  4. Northeast India Helminth Parasite Information Database (NEIHPID): Knowledge Base for Helminth Parasites.

    PubMed

    Biswal, Devendra Kumar; Debnath, Manish; Kharumnuid, Graciously; Thongnibah, Welfrank; Tandon, Veena

    2016-01-01

    Most metazoan parasites that invade vertebrate hosts belong to three phyla: Platyhelminthes, Nematoda and Acanthocephala. Many of the parasitic members of these phyla are collectively known as helminths and are causative agents of many debilitating, deforming and lethal diseases of humans and animals. The North-East India Helminth Parasite Information Database (NEIHPID) project aimed to document and characterise the spectrum of helminth parasites in the north-eastern region of India, providing host, geographical distribution, diagnostic characters and image data. The morphology-based taxonomic data are supplemented with information on DNA sequences of nuclear, ribosomal and mitochondrial gene marker regions that aid in parasite identification. In addition, the database contains raw next generation sequencing (NGS) data for 3 foodborne trematode parasites, with more to follow. The database will also provide study material for students interested in parasite biology. Users can search the database at various taxonomic levels (phylum, class, order, superfamily, family, genus, and species), or by host, habitat and geographical location. Specimen collection locations are noted as co-ordinates in a MySQL database and can be viewed on Google maps, using Google Maps JavaScript API v3. The NEIHPID database has been made freely available at http://nepiac.nehu.ac.in/index.php.

  5. Viruses of parasites as actors in the parasite-host relationship: A "ménage à trois".

    PubMed

    Gómez-Arreaza, Amaranta; Haenni, Anne-Lise; Dunia, Irene; Avilán, Luisana

    2017-02-01

    The complex parasite-host relationship involves multiple mechanisms. Moreover, parasites infected by viruses modify this relationship adding more complexity to the system that now comprises three partners. Viruses infecting parasites were described several decades ago. However, until recently little was known about the viruses involved and their impact on the resulting disease caused to the hosts. To clarify this situation, we have concentrated on parasitic diseases caused to humans and on how virus-infected parasites could alter the symptoms inflicted on the human host. It is clear that the effect caused to the human host depends on the virus and on the parasite it has infected. Consequently, the review is divided as follows: Viruses with a possible effect on the virulence of the parasite. This section reviews pertinent articles showing that infection of parasites by viruses might increase the detrimental effect of the tandem virus-parasite on the human host (hypervirulence) or decrease virulence of the parasite (hypovirulence). Parasites as vectors affecting the transmission of viruses. In some cases, the virus-infected parasite might facilitate the transfer of the virus to the human host. Parasites harboring viruses with unidentified effects on their host. In spite of recently renewed interest in parasites in connection with their viruses, there still remains a number of cases in which the effect of the virus of a given parasite on the human host remains ambiguous. The triangular relationship between the virus, the parasite and the host, and the modulation of the pathogenicity and virulence of the parasites by viruses should be taken into account in the rationale of fighting against parasites.

  6. A life cycle database for parasitic acanthocephalans, cestodes, and nematodes.

    PubMed

    Benesh, Daniel P; Lafferty, Kevin D; Kuris, Armand

    2017-03-01

    Parasitologists have worked out many complex life cycles over the last ~150 yr, yet there have been few efforts to synthesize this information to facilitate comparisons among taxa. Most existing host-parasite databases focus on particular host taxa, do not distinguish final from intermediate hosts, and lack parasite life-history information. We summarized the known life cycles of trophically transmitted parasitic acanthocephalans, cestodes, and nematodes. For 973 parasite species, we gathered information from the literature on the hosts infected at each stage of the parasite life cycle (8,510 host-parasite species associations), what parasite stage is in each host, and whether parasites need to infect certain hosts to complete the life cycle. We also collected life-history data for these parasites at each life cycle stage, including 2,313 development time measurements and 7,660 body size measurements. The result is the most comprehensive data summary available for these parasite taxa. In addition to identifying gaps in our knowledge of parasite life cycles, these data can be used to test hypotheses about life cycle evolution, host specificity, parasite life-history strategies, and the roles of parasites in food webs.

  7. Biodiversity loss decreases parasite diversity: theory and patterns

    USGS Publications Warehouse

    Lafferty, Kevin D.

    2012-01-01

    Past models have suggested host–parasite coextinction could lead to linear, or concave down relationships between free-living species richness and parasite richness. I explored several models for the relationship between parasite richness and biodiversity loss. Life cycle complexity, low generality of parasites and sensitivity of hosts reduced the robustness of parasite species to the loss of free-living species diversity. Food-web complexity and the ordering of extinctions altered these relationships in unpredictable ways. Each disassembly of a food web resulted in a unique relationship between parasite richness and the richness of free-living species, because the extinction trajectory of parasites was sensitive to the order of extinctions of free-living species. However, the average of many disassemblies tended to approximate an analytical model. Parasites of specialist hosts and hosts higher on food chains were more likely to go extinct in food-web models. Furthermore, correlated extinctions between hosts and parasites (e.g. if parasites share a host with a specialist predator) led to steeper declines in parasite richness with biodiversity loss. In empirical food webs with random removals of free-living species, the relationship between free-living species richness and parasite richness was, on average, quasi-linear, suggesting biodiversity loss reduces parasite diversity more than previously thought.

  8. A life cycle database for parasitic acanthocephalans, cestodes, and nematodes

    USGS Publications Warehouse

    Benesh, Daniel P.; Lafferty, Kevin D.; Kuris, Armand

    2017-01-01

    Parasitologists have worked out many complex life cycles over the last ~150 years, yet there have been few efforts to synthesize this information to facilitate comparisons among taxa. Most existing host-parasite databases focus on particular host taxa, do not distinguish final from intermediate hosts, and lack parasite life-history information. We summarized the known life cycles of trophically transmitted parasitic acanthocephalans, cestodes, and nematodes. For 973 parasite species, we gathered information from the literature on the hosts infected at each stage of the parasite life cycle (8510 host-parasite species associations), what parasite stage is in each host, and whether parasites need to infect certain hosts to complete the life cycle. We also collected life-history data for these parasites at each life cycle stage, including 2313 development time measurements and 7660 body size measurements. The result is the most comprehensive data summary available for these parasite taxa. In addition to identifying gaps in our knowledge of parasite life cycles, these data can be used to test hypotheses about life cycle evolution, host specificity, parasite life-history strategies, and the roles of parasites in food webs.

  9. Biodiversity loss decreases parasite diversity: theory and patterns

    PubMed Central

    Lafferty, Kevin D.

    2012-01-01

    Past models have suggested host–parasite coextinction could lead to linear, or concave down relationships between free-living species richness and parasite richness. I explored several models for the relationship between parasite richness and biodiversity loss. Life cycle complexity, low generality of parasites and sensitivity of hosts reduced the robustness of parasite species to the loss of free-living species diversity. Food-web complexity and the ordering of extinctions altered these relationships in unpredictable ways. Each disassembly of a food web resulted in a unique relationship between parasite richness and the richness of free-living species, because the extinction trajectory of parasites was sensitive to the order of extinctions of free-living species. However, the average of many disassemblies tended to approximate an analytical model. Parasites of specialist hosts and hosts higher on food chains were more likely to go extinct in food-web models. Furthermore, correlated extinctions between hosts and parasites (e.g. if parasites share a host with a specialist predator) led to steeper declines in parasite richness with biodiversity loss. In empirical food webs with random removals of free-living species, the relationship between free-living species richness and parasite richness was, on average, quasi-linear, suggesting biodiversity loss reduces parasite diversity more than previously thought. PMID:22966137

  10. Biodiversity loss decreases parasite diversity: theory and patterns.

    PubMed

    Lafferty, Kevin D

    2012-10-19

    Past models have suggested host-parasite coextinction could lead to linear, or concave down relationships between free-living species richness and parasite richness. I explored several models for the relationship between parasite richness and biodiversity loss. Life cycle complexity, low generality of parasites and sensitivity of hosts reduced the robustness of parasite species to the loss of free-living species diversity. Food-web complexity and the ordering of extinctions altered these relationships in unpredictable ways. Each disassembly of a food web resulted in a unique relationship between parasite richness and the richness of free-living species, because the extinction trajectory of parasites was sensitive to the order of extinctions of free-living species. However, the average of many disassemblies tended to approximate an analytical model. Parasites of specialist hosts and hosts higher on food chains were more likely to go extinct in food-web models. Furthermore, correlated extinctions between hosts and parasites (e.g. if parasites share a host with a specialist predator) led to steeper declines in parasite richness with biodiversity loss. In empirical food webs with random removals of free-living species, the relationship between free-living species richness and parasite richness was, on average, quasi-linear, suggesting biodiversity loss reduces parasite diversity more than previously thought.

  11. A world without parasites: exploring the hidden ecology of infection

    PubMed Central

    Johnson, Pieter TJ

    2016-01-01

    Parasites have historically been considered a scourge, deserving of annihilation. Although parasite eradications rank among humanity's greatest achievements, new research is shedding light on the collateral effects of parasite loss. Here, we explore a “world without parasites”: a thought experiment for illuminating the ecological roles that parasites play in ecosystems. While there is robust evidence for the effects of parasites on host individuals (eg affecting host vital rates), this exercise highlights how little we know about the influence of parasites on communities and ecosystems (eg altering energy flow through food webs). We present hypotheses for novel, interesting, and general effects of parasites. These hypotheses are largely untested, and should be considered a springboard for future research. While many uncertainties exist, the available evidence suggests that a world without parasites would be very different from the world we know, with effects extending from host individuals to populations, communities, and even ecosystems. PMID:28077932

  12. Active migration and passive transport of malaria parasites.

    PubMed

    Douglas, Ross G; Amino, Rogerio; Sinnis, Photini; Frischknecht, Freddy

    2015-08-01

    Malaria parasites undergo a complex life cycle between their hosts and vectors. During this cycle the parasites invade different types of cells, migrate across barriers, and transfer from one host to another. Recent literature hints at a misunderstanding of the difference between active, parasite-driven migration and passive, circulation-driven movement of the parasite or parasite-infected cells in the various bodily fluids of mosquito and mammalian hosts. Because both active migration and passive transport could be targeted in different ways to interfere with the parasite, a distinction between the two ways the parasite uses to get from one location to another is essential. We discuss the two types of motion needed for parasite dissemination and elaborate on how they could be targeted by future vaccines or drugs.

  13. Implications of bioactive solute transfer from hosts to parasitic plants.

    PubMed

    Smith, Jason D; Mescher, Mark C; De Moraes, Consuelo M

    2013-08-01

    Parasitic plants--which make their living by extracting nutrients and other resources from other plants--are important components of many natural ecosystems; and some parasitic species are also devastating agricultural pests. To date, most research on plant parasitism has focused on nutrient transfer from host to parasite and the impacts of parasites on host plants. Far less work has addressed potential effects of the translocation of bioactive non-nutrient solutes-such as phytohormones, secondary metabolites, RNAs, and proteins-on the development and physiology of parasitic plants and on their subsequent interactions with other organisms such as insect herbivores. A growing number of recent studies document the transfer of such molecules from hosts to parasites and suggest that they may have significant impacts on parasite physiology and ecology. We review this literature and discuss potential implications for management and priorities for future research.

  14. The glyoxalase pathway in protozoan parasites.

    PubMed

    Sousa Silva, Marta; Ferreira, António E N; Gomes, Ricardo; Tomás, Ana M; Ponces Freire, Ana; Cordeiro, Carlos

    2012-10-01

    The glyoxalase system is the main catabolic route for methylglyoxal, a non-enzymatic glycolytic byproduct with toxic and mutagenic effects. This pathway includes two enzymes, glyoxalase I and glyoxalase II, which convert methylglyoxal to d-lactate by using glutathione as a catalytic cofactor. In protozoan parasites the glyoxalase system shows marked deviations from this model. For example, the functional replacement of glutathione by trypanothione (a spermidine-glutathione conjugate) is a characteristic of trypanosomatids. Also interesting are the lack of glyoxalase I and the presence of two glyoxalase II enzymes in Trypanosoma brucei. In Plasmodium falciparum the glyoxalase pathway is glutathione-dependent, and glyoxalase I is an atypical monomeric enzyme with two active sites. Although it is tempting to exploit these differences for their potential therapeutic value, they provide invaluable clues regarding methylglyoxal metabolism and the evolution of protozoan parasites. Glyoxalase enzymes have been characterized in only a few protozoan parasites, namely Plasmodium falciparum and the trypanosomatids Leishmania and Trypanosoma. In this review, we will focus on the key features of the glyoxalase pathway in major human protozoan parasites, with particular emphasis on the characterized systems in Plasmodium falciparum, Trypanosoma brucei, Trypanosoma cruzi, and Leishmania spp. We will also search for genes encoding glyoxalase I and II in Toxoplasma gondii, Entamoeba histolytica, and Giardia lamblia.

  15. Parasitism enhances tilapia susceptibility to Flavobacterium columnare

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flavobacterium columnare, a Gram-negative bacterium, is the causative agent of columnaris disease. Many commercially important freshwater fish worldwide are susceptible to columnaris disease that can result in high fish mortality. Ichthyophthirius multifiliis (Ich) is a protozoan parasite in many ...

  16. Intestinal parasitic infections in hosted Saharawi children.

    PubMed

    Soriano, J M; Domènech, G; Martínez, M C; Mañes, J; Soriano, F

    2011-12-01

    Literatures on intestinal parasitic infections in Saharawi children were scarce and distributed in non parasitological journals. This was the first article that specifically highlighted on the prevalence of these infections in 270 Saharawi children aged from 6 to 12 years hosted in Spain. Six different intestinal parasites were identified in this study and 78, 46, 40, 24, 13 and 5 were positive for Giardia lamblia (29%), Entamoeba coli (17%), Blastocystis hominis (15%), Endolimax nana (9%), Hymenolepis nana (5%) and Enterobius vermicularis (2%), respectively. Mixed intestinal parasitic infections were seen in 12 (4.4%) studied children. Six (2.2%) double infections for G. lamblia and B. hominis were seen in these children while in four (1.5%) had G. lamblia and H. nana. Triple intestinal parasitic infections of G. lamblia, B. hominis and H. nana were observed in two (0.7%) of the children studied. In the other hand, about 14.8% of the studied children had a mild anaemia and 15.5 and 16.6% had iron deficiency and eosinophilia, respectively.

  17. Helminth parasites of Australasian monotremes and marsupials.

    PubMed

    Spratt, David M; Beveridge, Ian

    2016-06-15

    This work includes all published records, to April 2015, of the helminths occurring in Australasian monotremes and marsupials, with due regard for synonymy and an attempt to include life history studies, pathological observations and epidemiology. It also contains all unpublished records known to us and referrable, by accession numbers, to curated collections in Australia and overseas. Information is presented by host family, genus, species, sub-species or chromosome race and includes the names of all host species from which no parasites have been recorded. Most records pertain to free-living and wild animals; where they do not, they have been annotated appropriately. Unpublished information known to the authors has been included in annotations to entries, where appropriate. Parasites are arranged as follows: Trematoda, Cestoda, Nematoda, Acanthocephala, and their systematic position is indicated by abbreviations placed before the name. The authority for each parasite record is given after the author's name, as a number in parentheses, and this refers to the numbered (1-664) list of references.        A parasite-host list is presented alphabetically, irrespective of taxonomic affiliation together with the host species in which they are known to occur. Hosts are arranged initially by family and alphabetically within each family.

  18. [Parasitism by Amblyomma triste in domestic cat].

    PubMed

    da Silva, Aleksandro S; da Silva, Marcos K; Monteiro, Silvia G

    2007-01-01

    Amblyomma triste is an ixodidae, ectoparasite of several mammals' species, with occurrence reported in Argentina, Brazil, Colombia, Ecuador, Peru, Uruguay and Venezuela. The aim of this work was to register the parasitism by A. triste in domestic cat (Felis catus) in Rio Grande do Sul state, Brazil.

  19. Parasites in stranded cetaceans of Patagonia.

    PubMed

    Berón-Vera, Bárbara; Crespo, Enrique A; Raga, Juan A

    2008-08-01

    There is an increasing interest in parasites of marine mammals of Argentina. Here, we examined several poorly known cetaceans, i.e., 2 spectacled porpoises and 1 Burmeister's porpoise (Phocoenidae), and 1 Gray's beaked whale and 1 Cuvier's beaked whale (Ziphidae); we also updated the parasite information for 1 sperm whale (Physeteridae). These hosts strand only occasionally. We found Anisakis simplex s.l. in 2 spectacled porpoises and the Burmeister's porpoise, and recorded its distribution among the stomach chambers. Anisakis physeteris infected the sperm whale; Corynosoma cetaceum occurred in the duodenal ampulla of the Burmeister's porpoise; Corynosoma australe was found in the posterior-most region of the intestine of 1 spectacled porpoise, while another one had Tetrabothrius sp. in the anal crypts; Corynosoma bullosum and Corynosoma sp. were found in the sperm whale. The only digenean found was Pholeter gastrophilus in the Burmeister's porpoise. Merocercoids of Phyllobothrium delphini were present in the blubber of 1 spectacled porpoise, the sperm whale, and the Gray's beaked whale, while Scolex pleuronectis infected the Gray's beaked whale and 1 spectacled porpoise. No parasites were recovered from the Cuvier's beaked whale. Poor parasite-species assemblages are consistent in marine mammals of Patagonia. Given the conservation status of these hosts, the limited parasitological information gathered is valuable for conservation or management of these hosts in Patagonia.

  20. ZOONOTIC PARASITES, OUR ENVIROMENT AND CHANGE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Environmental changes arising from nature and human activity are affecting patterns for the occurrence and significance of many infectious diseases, including zoonotic parasites, which are those naturally transmitted between domestic animals or wildlife and people. As these changes continue, and pe...

  1. Cases of parasitic pneumonia in Scottish cattle.

    PubMed

    2016-02-06

    Parasitic pneumonia in cattleNutritional osteodystrophy in cattleWhite liver disease in lambsErysipelas in pigsLead poisoning and atherosclerosis in an eagle These are among matters discussed in the disease surveillance report for October 2015 from SAC Consulting: Veterinary Services (SAC C VS).

  2. Breaking beta: deconstructing the parasite transmission function

    PubMed Central

    McCallum, Hamish; Fenton, Andy; Hudson, Peter J.; Lee, Brian; Levick, Beth; Norman, Rachel

    2017-01-01

    Transmission is a fundamental step in the life cycle of every parasite but it is also one of the most challenging processes to model and quantify. In most host–parasite models, the transmission process is encapsulated by a single parameter β. Many different biological processes and interactions, acting on both hosts and infectious organisms, are subsumed in this single term. There are, however, at least two undesirable consequences of this high level of abstraction. First, nonlinearities and heterogeneities that can be critical to the dynamic behaviour of infections are poorly represented; second, estimating the transmission coefficient β from field data is often very difficult. In this paper, we present a conceptual model, which breaks the transmission process into its component parts. This deconstruction enables us to identify circumstances that generate nonlinearities in transmission, with potential implications for emergent transmission behaviour at individual and population scales. Such behaviour cannot be explained by the traditional linear transmission frameworks. The deconstruction also provides a clearer link to the empirical estimation of key components of transmission and enables the construction of flexible models that produce a unified understanding of the spread of both micro- and macro-parasite infectious disease agents. This article is part of the themed issue ‘Opening the black box: re-examining the ecology and evolution of parasite transmission’. PMID:28289252

  3. Molecular analysis of plant-parasitic nematodes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In addition to traditional morphology-based taxonomic approaches, molecular methods are often required to confirm diagnoses or to establish phylogenetic relationships among plant-parasitic nematodes. Current challenges, including limitations of existing methods, and new research directions will be d...

  4. Imaging of rickettsial, spirochetal, and parasitic infections.

    PubMed

    Akgoz, Ayca; Mukundan, Srini; Lee, Thomas C

    2012-11-01

    This article is an update and literature review of the clinical and neuroimaging findings of the commonly known rickettsial, spirochetal, and eukaryotic parasitic infections. Being familiar with clinical presentation and imaging findings of these infections is crucial for early diagnosis and treatment especially in patients who live in or have a travel history to endemic regions or are immunocompromised.

  5. Lipids of Parasitic and Saprophytic Leptospires

    PubMed Central

    Johnson, R. C.; Livermore, B. P.; Walby, Judith K.; Jenkin, H. M.

    1970-01-01

    The lipid composition of five parasitic and six saprophytic leptospires was compared. Lipids comprise 18 to 26% of the dry weight of the cells after chloroform-methanol extraction. No residual (bound) lipid was found after acid or alkaline hydrolysis of the extracted residue. The total lipid was composed of 60 to 70% phospholipid, and the remaining lipid was free fatty acids. The phospholipid fraction contained phosphatidylethanolamine as the major component, and phosphatidylglycerol and diphosphatidylglycerol were minor components with traces of lysophatidylethanolamine sometimes found. The major fatty acids of leptospires were hexadecanoic, hexadecenoic, and octadecenoic acids. Both the unusual cis-11-hexadecenoic acid and the more common cis-9-hexadecenoic acid were synthesized by the leptospires. Neither the parasitic nor the saprophytic leptospires can chain elongate fatty acids. However, they were capable of β-oxidation of fatty acids. Both groups of leptospires desaturate fatty acids by an aerobic pathway. When the parasite canicola was cultivated on octadecanoic acid, 87% of the hexadecenoic acid was the 11 isomer, whereas the saprophyte semeranga consisted of 10% of this isomer. In addition, the saprophytic leptospires contained more tetradecanoic acid than the parasites. No differences were observed in the lipid composition of virulent and avirulent strains of canicola. PMID:16557833

  6. Dealing with Parasites in Group Projects.

    ERIC Educational Resources Information Center

    Carter, Judy H.

    While it is generally accepted that people working in groups can accomplish more than people working individually, it is equally accepted that parasites will attempt to feed on the other group members. Group work has been called by several names--group learning, cooperative learning, collaborative learning--all of which carry slightly different…

  7. Indirect effects of parasites in invasions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduced species disrupt native communities and biodiversity worldwide. Parasitic infections (and at times, their absence) are thought to be a key component in the success and impact of biological invasions by plants and animals. They can facilitate or limit invasions, and positively or negatively...

  8. Impacts of globalization on foodborne parasites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In 2010 an estimated 3% of the world’s population lived outside their country of origin. Among immigrants, tourists, and business travellers worldwide several foodborne parasites are frequently found including Ascaris, Trichiuris, hookworms, Enterobius, Fasciola, Hymenolepis, and several protozoa. T...

  9. Blood parasites in North American waterfowl

    USGS Publications Warehouse

    Herman, C.M.

    1968-01-01

    One thing seems to stand out in the overall knowledge we have of the blood parasites of waterfowl, as previously noted by Herman and Wehr, (1954): the greatest potential of losses is in the younger age groups, usually those birds 5-10 weeks old. In Leucocytozoon infections, death occurs as early as the first or second week of the bird's life. As a conclusion to this presentation, I wish to emphasize that there are many gaps in our knowledge of these parasites and that the answers are to be obtained by further studies in the young birds. Data obtained from studies of birds shot by hunters or from specimens taken during fall or winter banding operations can be expected to be far less rewarding and significanf than studies of goslings and ducklings. We need much more knowledge of these parasites and their vectors and other relationships before we can develop management procedures to combat or contain them. It will require many more studies in depth to achieve this goal, but the facts are there waiting to be uncovered. These parasites will have to be regulated along with breeding habitat, hunter take, and other factors that all add up to maintenance and management of waterfowl.

  10. Quantifying Transmission Investment in Malaria Parasites.

    PubMed

    Greischar, Megan A; Mideo, Nicole; Read, Andrew F; Bjørnstad, Ottar N

    2016-02-01

    Many microparasites infect new hosts with specialized life stages, requiring a subset of the parasite population to forgo proliferation and develop into transmission forms. Transmission stage production influences infectivity, host exploitation, and the impact of medical interventions like drug treatment. Predicting how parasites will respond to public health efforts on both epidemiological and evolutionary timescales requires understanding transmission strategies. These strategies can rarely be observed directly and must typically be inferred from infection dynamics. Using malaria as a case study, we test previously described methods for inferring transmission stage investment against simulated data generated with a model of within-host infection dynamics, where the true transmission investment is known. We show that existing methods are inadequate and potentially very misleading. The key difficulty lies in separating transmission stages produced by different generations of parasites. We develop a new approach that performs much better on simulated data. Applying this approach to real data from mice infected with a single Plasmodium chabaudi strain, we estimate that transmission investment varies from zero to 20%, with evidence for variable investment over time in some hosts, but not others. These patterns suggest that, even in experimental infections where host genetics and other environmental factors are controlled, parasites may exhibit remarkably different patterns of transmission investment.

  11. Quantifying Transmission Investment in Malaria Parasites

    PubMed Central

    Greischar, Megan A.; Mideo, Nicole; Read, Andrew F.; Bjørnstad, Ottar N.

    2016-01-01

    Many microparasites infect new hosts with specialized life stages, requiring a subset of the parasite population to forgo proliferation and develop into transmission forms. Transmission stage production influences infectivity, host exploitation, and the impact of medical interventions like drug treatment. Predicting how parasites will respond to public health efforts on both epidemiological and evolutionary timescales requires understanding transmission strategies. These strategies can rarely be observed directly and must typically be inferred from infection dynamics. Using malaria as a case study, we test previously described methods for inferring transmission stage investment against simulated data generated with a model of within-host infection dynamics, where the true transmission investment is known. We show that existing methods are inadequate and potentially very misleading. The key difficulty lies in separating transmission stages produced by different generations of parasites. We develop a new approach that performs much better on simulated data. Applying this approach to real data from mice infected with a single Plasmodium chabaudi strain, we estimate that transmission investment varies from zero to 20%, with evidence for variable investment over time in some hosts, but not others. These patterns suggest that, even in experimental infections where host genetics and other environmental factors are controlled, parasites may exhibit remarkably different patterns of transmission investment. PMID:26890485

  12. [Parasitic diseases of the central nervous system].

    PubMed

    Schmutzhard, E

    2010-02-01

    Central nervous system infections and infestations by protozoa and helminths constitute a problem of increasing importance throughout all of central European and northern/western countries. This is partially due to the globalisation of our society, tourists and business people being more frequently exposed to parasitic infection/infestation in tropical countries than in moderate climate countries. On top of that, migrants may import chronic infestations and infections with parasitic pathogens, eventually also--sometimes exclusively--involving the nervous system. Knowledge of epidemiology, initial clinical signs and symptoms, diagnostic procedures as well as specific chemotherapeutic therapies and adjunctive therapeutic strategies is of utmost important in all of these infections and infestations of the nervous systems, be it by protozoa or helminths. This review lists, mainly in the form of tables, all possible infections and infestations of the nervous systems by protozoa and by helminths. Besides differentiating parasitic diseases of the nervous system seen in migrants, tourists etc., it is very important to have in mind that disease-related (e.g. HIV) or iatrogenic immunosuppression has led to the increased occurrence of a wide variety of parasitic infections and infestations of the nervous system (e. g. babesiosis, Chagas disease, Strongyloides stercoralis infestation, toxoplasmosis, etc.).

  13. Parasite Stress Predicts Offspring Sex Ratio

    PubMed Central

    Dama, Madhukar Shivajirao

    2012-01-01

    In this study, I predict that the global variation of offspring sex ratio might be influenced in part by the level of parasite stress. From an energetic standpoint, higher gestational costs of producing a male offspring could decrease male births in a population with limited resources. This implies that, any factor that limits the parental resources could be expected to favor female offspring production. Human sex ratio at birth (SRB) is believed to be influenced by numerous socioeconomic, biological, and environmental factors. Here, I test a prediction that parasite stress, by virtue of its effects on the general health condition, may limit the parental investment ability and therefore could influence the SRB at the population level. The statistical analysis supports this prediction, and show that the level of parasite stress has a significant inverse relation with population SRB across the world. Further, this relation is many-folds stronger than the association of SRB with other factors, like; polygyny, fertility, latitude, and son-preference. Hence, I propose that condition affecting ability of parasites (but not adaptive significance) could be a likely causal basis for the striking variation of SRB across populations. PMID:23049967

  14. How to catch a parasite: Parasite Niche Modeler (PaNic) meets Fishbase

    USGS Publications Warehouse

    Strona, Giovanni; Lafferty, Kevin D.

    2012-01-01

    Parasite Niche Modeler (PaNic) is a free online software tool that suggests potential hosts for fish parasites. For a particular parasite species from the major helminth groups (Acanthocephala, Cestoda, Monogenea, Nematoda, Trematoda), PaNic takes data from known hosts (maximum body length, growth rate, life span, age at first maturity, trophic level, phylogeny, and biogeography) and hypothesizes similar fish species that might serve as hosts to that parasite. Users can give varying weights to host attributes and create custom models. In addition to suggesting plausible hosts (with varying degrees of confidence), the models indicate known host species that appear to be outliers in comparison to other known hosts. These unique features make PaNic an innovative tool for addressing both theoretical and applied questions in fish parasitology. PaNic can be accessed at .

  15. Altitudinal variation in haemosporidian parasite distribution in great tit populations

    PubMed Central

    2013-01-01

    Background One of the major issues concerning disease ecology and conservation is knowledge of the factors that influence the distribution of parasites and consequently disease outbreaks. This study aimed to investigate avian haemosporidian composition and the distribution of these parasites in three altitudinally separated great tit (Parus major) populations in western Switzerland over a three-year period. The objectives were to determine the lineage diversity of parasites occuring across the study populations and to investigate whether altitudinal gradients govern the distribution of haemosporidian parasites by lineage. Methods In this study molecular approaches (PCR and sequencing) were used to detect avian blood parasites (Plasmodium sp., Haemoproteus sp. and Leucocytozoon sp.) in populations of adult great tits caught on their nests during three consecutive breeding seasons. Results High levels of parasite prevalence (88-96%) were found across all of the study populations with no significant altitude effect. Altitude did, however, govern the distribution of parasites belonging to different genera, with Plasmodium parasites being more prevalent at lower altitudes, Leucocytozoon parasites more at high altitude and Haemoproteus parasite prevalence increasing with altitude. A total of 27 haemosporidian parasite lineages were recorded across all study sites, with diversity showing a positive correlation to altitude. Parasites belonging to lineage SGS1 (P. relictum) and PARUS4 and PARUS19 (Leucocytozoon sp.) dominated lower altitudes. SW2 (P. polare) was the second most prevalent lineage of parasite detected overall and these parasites were responsible for 68% of infections at intermediate altitude, but were only documented at this one study site. Conclusions Avian haemosporidian parasites are not homogeneously distributed across host populations, but differ by altitude. This difference is most probably brought about by environmental factors influencing vector

  16. Host life history and host–parasite syntopy predict behavioural resistance and tolerance of parasites

    PubMed Central

    Sears, Brittany F.; Snyder, Paul W.; Rohr, Jason R.

    2016-01-01

    Summary There is growing interest in the role that life-history traits of hosts, such as their ‘pace-of-life’, play in the evolution of resistance and tolerance to parasites.Theory suggests that, relative to host species that have high syntopy (local spatial and temporal overlap) with parasites, host species with low syntopy should have lower selection pressures for more constitutive (always present) and costly defences, such as tolerance, and greater reliance on more inducible and cheaper defences, such as behaviour. Consequently, we postulated that the degree of host–parasite syntopy, which is negatively correlated with host pace-of-life (an axis reflecting the developmental rate of tadpoles and the inverse of their size at metamorphosis) in our tadpole–parasitic cercarial (trematode) system, would be a negative and positive predictor of behavioural resistance and tolerance, respectively.To test these hypotheses, we exposed seven tadpole species to a range of parasite (cercarial) doses crossed with anaesthesia treatments that controlled for anti-parasite behaviour. We quantified host behaviour, successful and unsuccessful infections, and each species’ reaction norm for behavioural resistance and tolerance, defined as the slope between cercarial exposure (or attempted infections) and anti-cercarial behaviours and mass change, respectively. Hence, tolerance is capturing any cost of parasite exposure.As hypothesized, tadpole pace-of-life was a significant positive predictor of behavioural resistance and negative predictor of tolerance, a result that is consistent with a trade-off between behavioural resistance and tolerance across species that warrants further investigation. Moreover, these results were robust to considerations of phylogeny, all possible re-orderings of the three fastest or slowest paced species, and various measurements of tolerance.These results suggest that host pace-of-life and host–parasite syntopy are powerful drivers of both the

  17. Host life history and host-parasite syntopy predict behavioural resistance and tolerance of parasites.

    PubMed

    Sears, Brittany F; Snyder, Paul W; Rohr, Jason R

    2015-05-01

    There is growing interest in the role that life-history traits of hosts, such as their 'pace-of-life', play in the evolution of resistance and tolerance to parasites. Theory suggests that, relative to host species that have high syntopy (local spatial and temporal overlap) with parasites, host species with low syntopy should have lower selection pressures for more constitutive (always present) and costly defences, such as tolerance, and greater reliance on more inducible and cheaper defences, such as behaviour. Consequently, we postulated that the degree of host-parasite syntopy, which is negatively correlated with host pace-of-life (an axis reflecting the developmental rate of tadpoles and the inverse of their size at metamorphosis) in our tadpole-parasitic cercarial (trematode) system, would be a negative and positive predictor of behavioural resistance and tolerance, respectively. To test these hypotheses, we exposed seven tadpole species to a range of parasite (cercarial) doses crossed with anaesthesia treatments that controlled for anti-parasite behaviour. We quantified host behaviour, successful and unsuccessful infections, and each species' reaction norm for behavioural resistance and tolerance, defined as the slope between cercarial exposure (or attempted infections) and anti-cercarial behaviours and mass change, respectively. Hence, tolerance is capturing any cost of parasite exposure. As hypothesized, tadpole pace-of-life was a significant positive predictor of behavioural resistance and negative predictor of tolerance, a result that is consistent with a trade-off between behavioural resistance and tolerance across species that warrants further investigation. Moreover, these results were robust to considerations of phylogeny, all possible re-orderings of the three fastest or slowest paced species, and various measurements of tolerance. These results suggest that host pace-of-life and host-parasite syntopy are powerful drivers of both the strength and type

  18. A combined parasitological molecular approach for noninvasive characterization of parasitic nematode communities in wild hosts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Most hosts are concurrently or sequentially infected with multiple parasites, thus fully understanding interactions between individual parasite species and their hosts depends on accurate characterization of the parasite community. For parasitic nematodes, non-invasive methods for obtaining quantita...

  19. Richness and distribution of tropical oyster parasites in two oceans.

    PubMed

    Pagenkopp Lohan, Katrina M; Hill-Spanik, Kristina M; Torchin, Mark E; Aguirre-Macedo, Leopoldina; Fleischer, Robert C; Ruiz, Gregory M

    2016-08-01

    Parasites can exert strong effects on population to ecosystem level processes, but data on parasites are limited for many global regions, especially tropical marine systems. Characterizing parasite diversity and distributions are the first steps towards understanding the potential impacts of parasites. The Panama Canal serves as an interesting location to examine tropical parasite diversity and distribution, as it is a conduit between two oceans and a hub for international trade. We examined metazoan and protistan parasites associated with ten oyster species collected from both Panamanian coasts, including the Panama Canal and Bocas del Toro. We found multiple metazoan taxa (pea crabs, Stylochus spp., Urastoma cyrinae). Our molecular screening for protistan parasites detected four species of Perkinsus (Perkinsus marinus, Perkinsus chesapeaki, Perkinsus olseni, Perkinsus beihaiensis) and several haplosporidians, including two genera (Minchinia, Haplosporidium). Species richness was higher for the protistan parasites than for the metazoans, with haplosporidian richness being higher than Perkinsus richness. Perkinsus species were the most frequently detected and most geographically widespread among parasite groups. Parasite richness and overlap differed between regions, locations and oyster hosts. These results have important implications for tropical parasite richness and the dispersal of parasites due to shipping associated with the Panama Canal.

  20. Host plant species affects virulence in monarch butterfly parasites.

    PubMed

    de Roode, Jacobus C; Pedersen, Amy B; Hunter, Mark D; Altizer, Sonia

    2008-01-01

    1. Studies have considered how intrinsic host and parasite properties determine parasite virulence, but have largely ignored the role of extrinsic ecological factors in its expression. 2. We studied how parasite genotype and host plant species interact to determine virulence of the protozoan parasite Ophryocystis elektroscirrha (McLaughlin & Myers 1970) in the monarch butterfly Danaus plexippus L. We infected monarch larvae with one of four parasite genotypes and reared them on two milkweed species that differed in their levels of cardenolides: toxic chemicals involved in predator defence. 3. Parasite infection, replication and virulence were affected strongly by host plant species. While uninfected monarchs lived equally long on both plant species, infected monarchs suffered a greater reduction in their life spans (55% vs. 30%) on the low-cardenolide vs. the high-cardenolide host plant. These life span differences resulted from different levels of parasite replication in monarchs reared on the two plant species. 4. The virulence rank order of parasite genotypes was unaffected by host plant species, suggesting that host plant species affected parasite genotypes similarly, rather than through complex plant species-parasite genotype interactions. 5. Our results demonstrate that host ecology importantly affects parasite virulence, with implications for host-parasite dynamics in natural populations.

  1. Egg size matching by an intraspecific brood parasite

    USGS Publications Warehouse

    Lemons, Patrick R.; Sedinger, James S.

    2011-01-01

    Avian brood parasitism provides an ideal system with which to understand animal recognition and its affect on fitness. This phenomenon of laying eggs in the nests of other individuals has classically been framed from the perspective of interspecific brood parasitism and host recognition of parasitic eggs. Few examples exist of strategies adopted by intraspecific brood parasites to maximize success of parasitic eggs. Intraspecific brood parasitism within precocial birds can be a risky strategy in that hatch synchrony is essential to reproductive success. Given that egg size is positively correlated with incubation time, parasitic birds would benefit by recognizing and selecting hosts with a similar egg size. Intraspecific brood parasitism is an alternative reproductive strategy in black brant (Branta bernicla nigricans), a colonial nesting goose with precocial young. Based on a randomization test, parasitic eggs in this study differed less in size from eggs in their host's nests than did random eggs placed in random nests. Parasitic eggs were remarkably similar in size to hosts’ eggs, differing by <2% of volume on average from host eggs, whereas randomly paired eggs in random nests differed by nearly 8%. The precision with which parasitic brant match the egg size of hosts in our study supports our hypothesis that brant match egg size of hosts, thereby maximizing hatching success of their parasitic eggs.

  2. Alternative prey use affects helminth parasite infections in grey wolves.

    PubMed

    Friesen, Olwyn C; Roth, James D

    2016-09-01

    Predators affect prey populations not only through direct predation, but also by acting as definitive hosts for their parasites and completing parasite life cycles. Understanding the affects of parasitism on prey population dynamics requires knowing how their predators' parasite community is affected by diet and prey availability. Ungulates, such as moose (Alces americanus) and white-tailed deer (Odocoileus virginianus), are often important prey for wolves (Canis lupus), but wolves also consume a variety of alternative prey, including beaver (Castor canadensis) and snowshoe hare (Lepus americanus). The use of alternative prey, which may host different or fewer parasites than ungulates, could potentially reduce overall abundance of ungulate parasites within the ecosystem, benefiting both wolves and ungulate hosts. We examined parasites in wolf carcasses from eastern Manitoba and estimated wolf diet using stable isotope analysis. Taeniidae cestodes were present in most wolves (75%), reflecting a diet primarily comprised of ungulates, but nematodes were unexpectedly rare. Cestode abundance was negatively related to the wolf's δ(13) C value, indicating diet affects parasite abundance. Wolves that consumed a higher proportion of beaver and caribou (Rangifer tarandus), estimated using Bayesian mixing models, had lower cestode abundance, suggesting the use of these alternative prey can reduce parasite loads. Long-term consumption of beavers may lower the abundance of adult parasites in wolves, eventually lowering parasite density in the region and ultimately benefiting ungulates that serve as intermediate hosts. Thus, alternative prey can affect both predator-prey and host-parasite interactions and potentially affect food web dynamics.

  3. Parasite treatment reduced Flavobacterium columnare infection in tilapia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacterium Flavobacterium columnare and parasite Trichodina are common pathogens of cultured fish. The authors conducted a study to evaluate whether treatment of Trichodina parasitized tilapia with formalin would improve fish survival and reduce F. columnare infection in fish. Tilapia parasitized by...

  4. The machinery underlying malaria parasite virulence is conserved between rodent and human malaria parasites

    PubMed Central

    De Niz, Mariana; Ullrich, Ann-Katrin; Heiber, Arlett; Blancke Soares, Alexandra; Pick, Christian; Lyck, Ruth; Keller, Derya; Kaiser, Gesine; Prado, Monica; Flemming, Sven; del Portillo, Hernando; Janse, Chris J.; Heussler, Volker; Spielmann, Tobias

    2016-01-01

    Sequestration of red blood cells infected with the human malaria parasite Plasmodium falciparum in organs such as the brain is considered important for pathogenicity. A similar phenomenon has been observed in mouse models of malaria, using the rodent parasite Plasmodium berghei, but it is unclear whether the P. falciparum proteins known to be involved in this process are conserved in the rodent parasite. Here we identify the P. berghei orthologues of two such key factors of P. falciparum, SBP1 and MAHRP1. Red blood cells infected with P. berghei parasites lacking SBP1 or MAHRP1a fail to bind the endothelial receptor CD36 and show reduced sequestration and virulence in mice. Complementation of the mutant P. berghei parasites with the respective P. falciparum SBP1 and MAHRP1 orthologues restores sequestration and virulence. These findings reveal evolutionary conservation of the machinery underlying sequestration of divergent malaria parasites and support the notion that the P. berghei rodent model is an adequate tool for research on malaria virulence. PMID:27225796

  5. Maternal androgens in avian brood parasites and their hosts: responses to parasitism and competition?

    USGS Publications Warehouse

    Hahn, Caldwell; Wingfield, John C.; Fox, David M.; Walker, Brian G.; Thomley, Jill E

    2017-01-01

    In the coevolutionary dynamic of avian brood parasites and their hosts, maternal (or transgenerational) effects have rarely been investigated. We examined the potential role of elevated yolk testosterone in eggs of the principal brood parasite in North America, the brown-headed cowbird, and three of its frequent host species. Elevated maternal androgens in eggs are a common maternal effect observed in many avian species when breeding conditions are unfavorable. These steroids accelerate embryo development, shorten incubation period, increase nestling growth rate, and enhance begging vigor, all traits that can increase the survival of offspring. We hypothesized that elevated maternal androgens in host eggs are a defense against brood parasitism. Our second hypothesis was that elevated maternal androgens in cowbird eggs are a defense against intra-specific competition. For host species, we found that elevated yolk testosterone was correlated with parasitized nests of small species, those whose nest success is most reduced by cowbird parasitism. For cowbirds, we found that elevated yolk testosterone was correlated with eggs in multiply-parasitized nests, which indicate intra-specific competition for nests due to high cowbird density. We propose experimental work to further examine the use of maternal effects by cowbirds and their hosts.

  6. The machinery underlying malaria parasite virulence is conserved between rodent and human malaria parasites.

    PubMed

    De Niz, Mariana; Ullrich, Ann-Katrin; Heiber, Arlett; Blancke Soares, Alexandra; Pick, Christian; Lyck, Ruth; Keller, Derya; Kaiser, Gesine; Prado, Monica; Flemming, Sven; Del Portillo, Hernando; Janse, Chris J; Heussler, Volker; Spielmann, Tobias

    2016-05-26

    Sequestration of red blood cells infected with the human malaria parasite Plasmodium falciparum in organs such as the brain is considered important for pathogenicity. A similar phenomenon has been observed in mouse models of malaria, using the rodent parasite Plasmodium berghei, but it is unclear whether the P. falciparum proteins known to be involved in this process are conserved in the rodent parasite. Here we identify the P. berghei orthologues of two such key factors of P. falciparum, SBP1 and MAHRP1. Red blood cells infected with P. berghei parasites lacking SBP1 or MAHRP1a fail to bind the endothelial receptor CD36 and show reduced sequestration and virulence in mice. Complementation of the mutant P. berghei parasites with the respective P. falciparum SBP1 and MAHRP1 orthologues restores sequestration and virulence. These findings reveal evolutionary conservation of the machinery underlying sequestration of divergent malaria parasites and support the notion that the P. berghei rodent model is an adequate tool for research on malaria virulence.

  7. Discrimination of fish populations using parasites: Random Forests on a 'predictable' host-parasite system.

    PubMed

    Pérez-Del-Olmo, A; Montero, F E; Fernández, M; Barrett, J; Raga, J A; Kostadinova, A

    2010-10-01

    We address the effect of spatial scale and temporal variation on model generality when forming predictive models for fish assignment using a new data mining approach, Random Forests (RF), to variable biological markers (parasite community data). Models were implemented for a fish host-parasite system sampled along the Mediterranean and Atlantic coasts of Spain and were validated using independent datasets. We considered 2 basic classification problems in evaluating the importance of variations in parasite infracommunities for assignment of individual fish to their populations of origin: multiclass (2-5 population models, using 2 seasonal replicates from each of the populations) and 2-class task (using 4 seasonal replicates from 1 Atlantic and 1 Mediterranean population each). The main results are that (i) RF are well suited for multiclass population assignment using parasite communities in non-migratory fish; (ii) RF provide an efficient means for model cross-validation on the baseline data and this allows sample size limitations in parasite tag studies to be tackled effectively; (iii) the performance of RF is dependent on the complexity and spatial extent/configuration of the problem; and (iv) the development of predictive models is strongly influenced by seasonal change and this stresses the importance of both temporal replication and model validation in parasite tagging studies.

  8. Expanding the antimalarial toolkit: Targeting host–parasite interactions

    PubMed Central

    Duffy, Patrick E.

    2016-01-01

    Recent successes in malaria control are threatened by drug-resistant Plasmodium parasites and insecticide-resistant Anopheles mosquitoes, and first generation vaccines offer only partial protection. New research approaches have highlighted host as well as parasite molecules or pathways that could be targeted for interventions. In this study, we discuss host–parasite interactions at the different stages of the Plasmodium life cycle within the mammalian host and the potential for therapeutics that prevent parasite migration, invasion, intracellular growth, or egress from host cells, as well as parasite-induced pathology. PMID:26834158

  9. Expanding the antimalarial toolkit: Targeting host-parasite interactions.

    PubMed

    Langhorne, Jean; Duffy, Patrick E

    2016-02-08

    Recent successes in malaria control are threatened by drug-resistant Plasmodium parasites and insecticide-resistant Anopheles mosquitoes, and first generation vaccines offer only partial protection. New research approaches have highlighted host as well as parasite molecules or pathways that could be targeted for interventions. In this study, we discuss host-parasite interactions at the different stages of the Plasmodium life cycle within the mammalian host and the potential for therapeutics that prevent parasite migration, invasion, intracellular growth, or egress from host cells, as well as parasite-induced pathology.

  10. Host stadium specificity in the gregarine assemblage parasitizing Tenebrio molitor.

    PubMed

    Clopton, R E; Janovy, J; Percival, T J

    1992-04-01

    Reciprocal cross-stadia experimental infections were used to demonstrate stadium specificity within the gregarine assemblage parasitizing Tenebrio molitor, the yellow mealworm. Gregarina cuneata, Gregarina polymorpha, and Gregarina steini are characteristic parasites of larval T. molitor. Gregarina niphandrodes is a characteristic parasite of adult T. molitor. Experimental infections were produced in all homologous host-parasite combinations. No infection was produced in heterologous or cross-stadia combinations. This study introduces the concept of separate, distinct parasite niches corresponding to separate life cycle stages and established by known, predictable life cycle events within a single host species.

  11. The study of parasite sharing for surveillance of zoonotic diseases

    NASA Astrophysics Data System (ADS)

    Farrell, Maxwell J.; Berrang-Ford, Lea; Davies, T. Jonathan

    2013-03-01

    Determining the factors that influence the transmission of parasites among hosts is important for directing surveillance of animal parasites before they successfully emerge in humans, and increasing the efficacy of programs for the control and management of zoonotic diseases. Here we present a review of recent advances in the study of parasite sharing, wildlife ecology, and epidemiology that could be extended and incorporated into proactive surveillance frameworks for multi-host infectious diseases. These methods reflect emerging interdisciplinary techniques with significant promise for the identification of future zoonotic parasites and unknown reservoirs of current zoonoses, strategies for the reduction of parasite prevalence and transmission among hosts, and decreasing the burden of infectious diseases.

  12. Interspecific brood parasitism in blackbirds (Icterinae): a phylogenetic perspective.

    PubMed

    Lanyon, S M

    1992-01-03

    An 852-base pair region of the cytochrome-b gene was sequenced for the brood parasitic cowbirds and 20 additional taxa of the New World blackbirds (Icterinae). The goal of the study was to determine (i) whether interspecific brood parasitism is multiply derived within the assemblage and (ii) the nature of the evolutionary transformation between various forms of interspecific brood parasitism. Cladistic analysis of the sequence data indicates that brood parasitism evolved a single time within the Icterinae. The primitive form of interspecific brood parasitism in this assemblage is host-specificity, with host-generality representing the derived condition.

  13. Parasites in grizzly bears from the central Canadian Arctic.

    PubMed

    Gau, R J; Kutz, S; Elkin, B T

    1999-07-01

    Standardized flotation techniques were used to survey 56 grizzly bear (Ursus arctos) fecal samples for parasites. The samples were collected during the spring and autumn of 1995 and 1996 in the central Arctic of the Northwest Territories (Canada). Parasites of the genera Nematodirus, gastrointestinal coccidia, and an unidentified first stage protostrongylid larva are reported for the first time from grizzly bear feces in North America. Parasites of the genera Diphyllobothrium and Baylisascaris also were collected. Prevalence of gastrointestinal parasites were significantly different between the spring and autumn seasons (31% and 58% respectively). Thus, we provide evidence supporting the theory that bears void gastrointestinal parasites before hibernation.

  14. 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

  15. A Lack of Parasitic Reduction in the Obligate Parasitic Green Alga Helicosporidium

    PubMed Central

    Pombert, Jean-François; Blouin, Nicolas Achille; Lane, Chris; Boucias, Drion; Keeling, Patrick J.

    2014-01-01

    The evolution of an obligate parasitic lifestyle is often associated with genomic reduction, in particular with the loss of functions associated with increasing host-dependence. This is evident in many parasites, but perhaps the most extreme transitions are from free-living autotrophic algae to obligate parasites. The best-known examples of this are the apicomplexans such as Plasmodium, which evolved from algae with red secondary plastids. However, an analogous transition also took place independently in the Helicosporidia, where an obligate parasite of animals with an intracellular infection mechanism evolved from algae with green primary plastids. We characterised the nuclear genome of Helicosporidium to compare its transition to parasitism with that of apicomplexans. The Helicosporidium genome is small and compact, even by comparison with the relatively small genomes of the closely related green algae Chlorella and Coccomyxa, but at the functional level we find almost no evidence for reduction. Nearly all ancestral metabolic functions are retained, with the single major exception of photosynthesis, and even here reduction is not complete. The great majority of genes for light-harvesting complexes, photosystems, and pigment biosynthesis have been lost, but those for other photosynthesis-related functions, such as Calvin cycle, are retained. Rather than loss of whole function categories, the predominant reductive force in the Helicosporidium genome is a contraction of gene family complexity, but even here most losses affect families associated with genome maintenance and expression, not functions associated with host-dependence. Other gene families appear to have expanded in response to parasitism, in particular chitinases, including those predicted to digest the chitinous barriers of the insect host or remodel the cell wall of Helicosporidium. Overall, the Helicosporidium genome presents a fascinating picture of the early stages of a transition from free

  16. Homage to Linnaeus: How many parasites? How many hosts?

    USGS Publications Warehouse

    Dobson, Andy; Lafferty, Kevin D.; Kuris, Armand M.; Hechinger, Ryan F.; Jetz, Walter

    2008-01-01

    Estimates of the total number of species that inhabit the Earth have increased significantly since Linnaeus's initial catalog of 20,000 species. The best recent estimates suggest that there are ≈6 million species. More emphasis has been placed on counts of free-living species than on parasitic species. We rectify this by quantifying the numbers and proportion of parasitic species. We estimate that there are between 75,000 and 300,000 helminth species parasitizing the vertebrates. We have no credible way of estimating how many parasitic protozoa, fungi, bacteria, and viruses exist. We estimate that between 3% and 5% of parasitic helminths are threatened with extinction in the next 50 to 100 years. Because patterns of parasite diversity do not clearly map onto patterns of host diversity, we can make very little prediction about geographical patterns of threat to parasites. If the threats reflect those experienced by avian hosts, then we expect climate change to be a major threat to the relatively small proportion of parasite diversity that lives in the polar and temperate regions, whereas habitat destruction will be the major threat to tropical parasite diversity. Recent studies of food webs suggest that ≈75% of the links in food webs involve a parasitic species; these links are vital for regulation of host abundance and potentially for reducing the impact of toxic pollutants. This implies that parasite extinctions may have unforeseen costs that impact the health and abundance of a large number of free-living species.

  17. Parasitic Infestation in Pediatric and Adolescent Appendicitis: A Local Experience

    PubMed Central

    Zakaria, Ossama M.; Zakaria, Hazem M.; Daoud, Mohamed Yasser; Al Wadaani, Hamed; Al Buali, Waleed; Al-Mohammed, Hamdan; Al Mulhim, Abdulrahman S.; Zaki, Wafaa

    2013-01-01

    Objective The relationship between parasites and pediatric appendicitis is a highly debatable issue. This study aims to investigate the role of parasitic infestation in the etiology of acute pediatric appendicitis. Methods A retrospective study including 1600 pediatric and adolescent patients who had undergone surgical therapy for a diagnosis of acute appendicitis over a period of ten years from Jan 2001 to Dec 2010. Demographic data were retrieved including the patient's age, sex, clinical data, clinical presentations, laboratory investigations, operative data and pathological findings to identify the presence and type of parasites. Patients were divided into two groups according to the presence or absence of parasites in the appendix lumen. In group I (n: 88), parasitic infestation was observed, whereas in group II (n: 1502), no parasitic infestation was present. Results Parasites were present in 5.5% (88 patients), and of those 88 parasitic infestations, 45 (51.1%) were Enterobaisis, 8 (9.1%) were Schistosomiasis, 23 (26.1%) were Ascariasis, 7 (8%) Trichuriasis, and 5 (5.7%) were Teania Saginata. The percentage of patients with suppurative, gangrenous or perforated appendicitis was similar in both groups with no statistical significance, irrespective of the presence or absence of parasitic infestation. Conclusion The low prevalence of parasites among the appendectomy specimens did not support the notion that parasites were a major cause of appendicitis in pediatric patients. PMID:23599875

  18. Homage to Linnaeus: How many parasites? How many hosts?

    PubMed Central

    Dobson, Andy; Lafferty, Kevin D.; Kuris, Armand M.; Hechinger, Ryan F.; Jetz, Walter

    2008-01-01

    Estimates of the total number of species that inhabit the Earth have increased significantly since Linnaeus's initial catalog of 20,000 species. The best recent estimates suggest that there are ≈6 million species. More emphasis has been placed on counts of free-living species than on parasitic species. We rectify this by quantifying the numbers and proportion of parasitic species. We estimate that there are between 75,000 and 300,000 helminth species parasitizing the vertebrates. We have no credible way of estimating how many parasitic protozoa, fungi, bacteria, and viruses exist. We estimate that between 3% and 5% of parasitic helminths are threatened with extinction in the next 50 to 100 years. Because patterns of parasite diversity do not clearly map onto patterns of host diversity, we can make very little prediction about geographical patterns of threat to parasites. If the threats reflect those experienced by avian hosts, then we expect climate change to be a major threat to the relatively small proportion of parasite diversity that lives in the polar and temperate regions, whereas habitat destruction will be the major threat to tropical parasite diversity. Recent studies of food webs suggest that ≈75% of the links in food webs involve a parasitic species; these links are vital for regulation of host abundance and potentially for reducing the impact of toxic pollutants. This implies that parasite extinctions may have unforeseen costs that impact the health and abundance of a large number of free-living species. PMID:18695218

  19. The evolution of host protection by vertically transmitted parasites

    PubMed Central

    Jones, Edward O.; White, Andrew; Boots, Michael

    2011-01-01

    Hosts are often infected by a variety of different parasites, leading to competition for hosts and coevolution between parasite species. There is increasing evidence that some vertically transmitted parasitic symbionts may protect their hosts from further infection and that this protection may be an important reason for their persistence in nature. Here, we examine theoretically when protection is likely to evolve and its selective effects on other parasites. Our key result is that protection is most likely to evolve in response to horizontally transmitted parasites that cause a significant reduction in host fecundity. The preponderance of sterilizing horizontally transmitted parasites found in arthropods may therefore explain the evolution of protection seen by their symbionts. We also find that protection is more likely to evolve in response to highly transmissible parasites that cause intermediate, rather than high, virulence (increased death rate when infected). Furthermore, intermediate levels of protection select for faster, more virulent horizontally transmitted parasites, suggesting that protective symbionts may lead to the evolution of more virulent parasites in nature. When we allow for coevolution between the symbiont and the parasite, more protection is likely to evolve in the vertically transmitted symbionts of longer lived hosts. Therefore, if protection is found to be common in nature, it has the potential to be a major selective force on host–parasite interactions. PMID:20861052

  20. Parasites in food webs: the ultimate missing links.

    PubMed

    Lafferty, Kevin D; Allesina, Stefano; Arim, Matias; Briggs, Cherie J; De Leo, Giulio; Dobson, Andrew P; Dunne, Jennifer A; Johnson, Pieter T J; Kuris, Armand M; Marcogliese, David J; Martinez, Neo D; Memmott, Jane; Marquet, Pablo A; McLaughlin, John P; Mordecai, Erin A; Pascual, Mercedes; Poulin, Robert; Thieltges, David W

    2008-06-01

    Parasitism is the most common consumer strategy among organisms, yet only recently has there been a call for the inclusion of infectious disease agents in food webs. The value of this effort hinges on whether parasites affect food-web properties. Increasing evidence suggests that parasites have the potential to uniquely alter food-web topology in terms of chain length, connectance and robustness. In addition, parasites might affect food-web stability, interaction strength and energy flow. Food-web structure also affects infectious disease dynamics because parasites depend on the ecological networks in which they live. Empirically, incorporating parasites into food webs is straightforward. We may start with existing food webs and add parasites as nodes, or we may try to build food webs around systems for which we already have a good understanding of infectious processes. In the future, perhaps researchers will add parasites while they construct food webs. Less clear is how food-web theory can accommodate parasites. This is a deep and central problem in theoretical biology and applied mathematics. For instance, is representing parasites with complex life cycles as a single node equivalent to representing other species with ontogenetic niche shifts as a single node? Can parasitism fit into fundamental frameworks such as the niche model? Can we integrate infectious disease models into the emerging field of dynamic food-web modelling? Future progress will benefit from interdisciplinary collaborations between ecologists and infectious disease biologists.

  1. Species loss on spatial patterns and composition of zoonotic parasites

    PubMed Central

    Harris, Nyeema C.; Dunn, Robert R.

    2013-01-01

    Species loss can result in the subsequent loss of affiliate species. Though largely ignored to date, these coextinctions can pose threats to human health by altering the composition, quantity and distribution of zoonotic parasites. We simulated host extinctions from more than 1300 host–parasite associations for 29 North American carnivores to investigate changes in parasite composition and species richness. We also explored the geography of zoonotic parasite richness under three carnivore composition scenarios and examined corresponding levels of human exposure. We found that changes in parasite assemblages differed among parasite groups. Because viruses tend to be generalists, the proportion of parasites that are viruses increased as more carnivores went extinct. Coextinction of carnivore parasites is unlikely to be common, given that few specialist parasites exploit hosts of conservation concern. However, local extirpations of widespread carnivore hosts can reduce overall zoonotic richness and shift distributions of parasite-rich areas. How biodiversity influences disease risks remains the subject of debate. Our results make clear that hosts vary in their contribution to human health risks. As a consequence, so too does the loss (or gain) of particular hosts. Anticipating changes in host composition in future environments may help inform parasite conservation and disease mitigation efforts. PMID:24068356

  2. Parasites in food webs: the ultimate missing links

    PubMed Central

    Lafferty, Kevin D; Allesina, Stefano; Arim, Matias; Briggs, Cherie J; De Leo, Giulio; Dobson, Andrew P; Dunne, Jennifer A; Johnson, Pieter T J; Kuris, Armand M; Marcogliese, David J; Martinez, Neo D; Memmott, Jane; Marquet, Pablo A; McLaughlin, John P; Mordecai, Erin A; Pascual, Mercedes; Poulin, Robert; Thieltges, David W

    2008-01-01

    Parasitism is the most common consumer strategy among organisms, yet only recently has there been a call for the inclusion of infectious disease agents in food webs. The value of this effort hinges on whether parasites affect food-web properties. Increasing evidence suggests that parasites have the potential to uniquely alter food-web topology in terms of chain length, connectance and robustness. In addition, parasites might affect food-web stability, interaction strength and energy flow. Food-web structure also affects infectious disease dynamics because parasites depend on the ecological networks in which they live. Empirically, incorporating parasites into food webs is straightforward. We may start with existing food webs and add parasites as nodes, or we may try to build food webs around systems for which we already have a good understanding of infectious processes. In the future, perhaps researchers will add parasites while they construct food webs. Less clear is how food-web theory can accommodate parasites. This is a deep and central problem in theoretical biology and applied mathematics. For instance, is representing parasites with complex life cycles as a single node equivalent to representing other species with ontogenetic niche shifts as a single node? Can parasitism fit into fundamental frameworks such as the niche model? Can we integrate infectious disease models into the emerging field of dynamic food-web modelling? Future progress will benefit from interdisciplinary collaborations between ecologists and infectious disease biologists. PMID:18462196

  3. Coevolution of parasite virulence and host mating strategies.

    PubMed

    Ashby, Ben; Boots, Michael

    2015-10-27

    Parasites are thought to play an important role in sexual selection and the evolution of mating strategies, which in turn are likely to be critical to the transmission and therefore the evolution of parasites. Despite this clear interdependence we have little understanding of parasite-mediated sexual selection in the context of reciprocal parasite evolution. Here we develop a general coevolutionary model between host mate preference and the virulence of a sexually transmitted parasite. We show when the characteristics of both the host and parasite lead to coevolutionarily stable strategies or runaway selection, and when coevolutionary cycling between high and low levels of host mate choosiness and virulence is possible. A prominent argument against parasites being involved in sexual selection is that they should evolve to become less virulent when transmission depends on host mating success. The present study, however, demonstrates that coevolution can maintain stable host mate choosiness and parasite virulence or indeed coevolutionary cycling of both traits. We predict that choosiness should vary inversely with parasite virulence and that both relatively long and short life spans select against choosy behavior in the host. The model also reveals that hosts can evolve different behavioral responses from the same initial conditions, which highlights difficulties in using comparative analysis to detect parasite-mediated sexual selection. Taken as a whole, our results emphasize the importance of viewing parasite-mediated sexual selection in the context of coevolution.

  4. Parasites in food webs: the ultimate missing links

    USGS Publications Warehouse

    Lafferty, Kevin D.; Allesina, Stefano; Arim, Matias; Briggs, Cherie J.; De Leo, Giulio A.; Dobson, Andrew P.; Dunne, Jennifer A.; Johnson, Pieter T.J.; Kuris, Armand M.; Marcogliese, David J.; Martinez, Neo D.; Memmott, Jane; Marquet, Pablo A.; McLaughlin, John P.; Mordecai, Eerin A.; Pascual, Mercedes; Poulin, Robert; Thieltges, David W.

    2008-01-01

    Parasitism is the most common consumer strategy among organisms, yet only recently has there been a call for the inclusion of infectious disease agents in food webs. The value of this effort hinges on whether parasites affect food-web properties. Increasing evidence suggests that parasites have the potential to uniquely alter food-web topology in terms of chain length, connectance and robustness. In addition, parasites might affect food-web stability, interaction strength and energy flow. Food-web structure also affects infectious disease dynamics because parasites depend on the ecological networks in which they live. Empirically, incorporating parasites into food webs is straightforward. We may start with existing food webs and add parasites as nodes, or we may try to build food webs around systems for which we already have a good understanding of infectious processes. In the future, perhaps researchers will add parasites while they construct food webs. Less clear is how food-web theory can accommodate parasites. This is a deep and central problem in theoretical biology and applied mathematics. For instance, is representing parasites with complex life cycles as a single node equivalent to representing other species with ontogenetic niche shifts as a single node? Can parasitism fit into fundamental frameworks such as the niche model? Can we integrate infectious disease models into the emerging field of dynamic food-web modelling? Future progress will benefit from interdisciplinary collaborations between ecologists and infectious disease biologists.

  5. Big bang in the evolution of extant malaria parasites.

    PubMed

    Hayakawa, Toshiyuki; Culleton, Richard; Otani, Hiroto; Horii, Toshihiro; Tanabe, Kazuyuki

    2008-10-01

    Malaria parasites (genus Plasmodium) infect all classes of terrestrial vertebrates and display host specificity in their infections. It is therefore assumed that malaria parasites coevolved intimately with their hosts. Here, we propose a novel scenario of malaria parasite-host coevolution. A phylogenetic tree constructed using the malaria parasite mitochondrial genome reveals that the extant primate, rodent, bird, and reptile parasite lineages rapidly diverged from a common ancestor during an evolutionary short time period. This rapid diversification occurred long after the establishment of the primate, rodent, bird, and reptile host lineages, which implies that host-switch events contributed to the rapid diversification of extant malaria parasite lineages. Interestingly, the rapid diversification coincides with the radiation of the mammalian genera, suggesting that adaptive radiation to new mammalian hosts triggered the rapid diversification of extant malaria parasite lineages.

  6. [Views for research development of control of parasitic diseases].

    PubMed

    Zhao, Qin-Ping; Dong, Hui-Fen; Jiang, Ming-Sen

    2013-12-01

    With the social and technological development, new understandings have been emerged for the research development of the control of parasitic diseases. The present review argues that: the traditional point of view for the control of parasitic diseases, eliminating parasites/media, should be updated. For the long-term interests of science and human perspective, biological diversity, including the parasite biodiversity, and ecological environment should be paid much more attention during the control of parasitic diseases. The leading role of society, economy and culture should be fully developed in the control of parasitic diseases with the progress of scientific and technology, to find a final way of sustainable development in the control of parasitic diseases.

  7. Exploiting structural biology in the fight against parasitic diseases.

    PubMed

    Modis, Yorgo

    2012-04-01

    Despite spectacular advances in structural biology over the past half-century, only approximately 2% of the structures in the Protein Data Bank are from eukaryotic parasites and less than 0.5% are from multicellular parasites. Even when only major human pathogens are considered, 3D structures of parasites are vastly underrepresented. Yet approximately one-third of the global burden of human disease comes from parasites. It is time to divert greater effort and resources in structural biology to benefit the fight against parasitic diseases. Using as leverage recent technological and methodological advances, a concerted effort to determine macromolecular structures from parasite pathogens would provide invaluable mechanistic insights on vital processes of the parasites and would suggest novel strategies for inhibiting infection.

  8. Host and Parasite Evolution in a Tangled Bank.

    PubMed

    Betts, Alex; Rafaluk, Charlotte; King, Kayla C

    2016-11-01

    Most hosts and parasites exist in diverse communities wherein they interact with other species, spanning the parasite-mutualist continuum. These additional interactions have the potential to impose selection on hosts and parasites and influence the patterns and processes of their evolution. Yet, host-parasite interactions are almost exclusively studied in species pairs. A wave of new research has incorporated a multispecies community context, showing that additional ecological interactions can alter components of host and parasite fitness, as well as interaction specificity and virulence. Here, we synthesize these findings to assess the effects of increased species diversity on the patterns and processes of host and parasite evolution. We argue that our understanding of host-parasite interactions would benefit from a richer biotic perspective.

  9. Lateralized courtship in a parasitic wasp.

    PubMed

    Romano, Donato; Donati, Elisa; Canale, Angelo; Messing, Russell H; Benelli, Giovanni; Stefanini, Cesare

    2016-01-01

    Lateralization (i.e. left-right asymmetries in the brain and behaviour) of courtship displays has been examined in a growing number vertebrate species, while evidence for invertebrates is limited. In this study, we investigated lateralization of courtship and mating displays in the parasitic wasp Leptomastidea abnormis. Results showed a population-level lateralization of male courtship displays. Male antennal tapping on the female's head was right-biased. However, right-biased male courtship acts were not characterized by higher male antennal tapping frequencies, nor success in mating although antennal tapping frequency was higher in males with mating success with respect to unsuccessful males. Overall, our results add basic knowledge to the behavioural ecology of insect parasitoids. To the best of our knowledge, this is the first report of behavioural lateralization in parasitic Hymenoptera.

  10. Anthelmintic metabolism in parasitic helminths: proteomic insights.

    PubMed

    Brophy, Peter M; MacKintosh, Neil; Morphew, Russell M

    2012-08-01

    Anthelmintics are the cornerstone of parasitic helminth control. Surprisingly, understanding of the biochemical pathways used by parasitic helminths to detoxify anthelmintics is fragmented, despite the increasing global threat of anthelmintic resistance within the ruminant and equine industries. Reductionist biochemistry has likely over-estimated the enzymatic role of glutathione transferases in anthelmintic metabolism and neglected the potential role of the cytochrome P-450 superfamily (CYPs). Proteomic technologies offers the opportunity to support genomics, reverse genetics and pharmacokinetics, and provide an integrated insight into both the cellular mechanisms underpinning response to anthelmintics and also the identification of biomarker panels for monitoring the development of anthelmintic resistance. To date, there have been limited attempts to include proteomics in anthelmintic metabolism studies. Optimisations of membrane, post-translational modification and interaction proteomic technologies in helminths are needed to especially study Phase I CYPs and Phase III ABC transporter pumps for anthelmintics and their metabolites.

  11. A naked ape would have fewer parasites.

    PubMed Central

    Pagel, Mark; Bodmer, Walter

    2003-01-01

    Unusually among the mammals, humans lack an outer layer of protective fur or hair. We propose the hypothesis that humans evolved hairlessness to reduce parasite loads, especially ectoparasites that may carry disease. We suggest that hairlessness is maintained by these naturally selected benefits and by sexual selection operating on both sexes. Hairlessness is made possible in humans owing to their unique abilities to regulate their environment via fire, shelter and clothing. Clothes and shelters allow a more flexible response to the external environment than a permanent layer of fur and can be changed or cleaned if infested with parasites. Naked molerats, another hairless and non-aquatic mammal species, also inhabit environments in which ectoparasite transmission is expected to be high, but in which temperatures are closely regulated. Our hypothesis explains features of human hairlessness-such as the marked sex difference in body hair, and its retention in the pubic regions-that are not explained by other theories. PMID:12952654

  12. Mathematical studies of parasitic infection and immunity.

    PubMed

    Anderson, R M

    1994-06-24

    The techniques that underpin modern molecular biology have been rapidly adopted by those interested in the major parasitic infections of humans. The parasitological literature is full of reports of genes and their amino acid sequences, of molecules, of cell membrane receptors and channels, and of the fine details of the immunological responses mounted by the host to combat infection. Much less enthusiasm has been shown for the mathematical techniques that facilitate the analysis and interpretation of dynamical processes such as transmission, evolution, and the interplay between parasite population growth and immunological responses within the host. Molecular techniques provide enormous opportunities for description, but ultimately, understanding biological systems with the precision that physicists and engineers aspire to in their own fields will require quantitative description of the many rate processes that dictate both an observed pattern and the dynamics of its change.

  13. Bacterial and parasitic diseases of selected invertebrates.

    PubMed

    Klaphake, Eric

    2009-09-01

    Invertebrate medicine is a rapidly advancing aspect of veterinary medicine, although frustrating in its lack of answers and its limitations compared with vertebrate medicine. Because invertebrates make up 98% of animal life, it should be impossible to contain information on their known bacterial and parasitic diseases within a single article. When the focus is placed on those species commonly kept and treated by non-marine veterinarians, the amount of information becomes manageable. Many exotic species had their known diseases and treatments start this way and then advanced to a higher level of understanding. This article stands as an introduction to the parasitic and bacterial diseases of these fascinating creatures for the veterinary practitioner.

  14. A naked ape would have fewer parasites.

    PubMed

    Pagel, Mark; Bodmer, Walter

    2003-08-07

    Unusually among the mammals, humans lack an outer layer of protective fur or hair. We propose the hypothesis that humans evolved hairlessness to reduce parasite loads, especially ectoparasites that may carry disease. We suggest that hairlessness is maintained by these naturally selected benefits and by sexual selection operating on both sexes. Hairlessness is made possible in humans owing to their unique abilities to regulate their environment via fire, shelter and clothing. Clothes and shelters allow a more flexible response to the external environment than a permanent layer of fur and can be changed or cleaned if infested with parasites. Naked molerats, another hairless and non-aquatic mammal species, also inhabit environments in which ectoparasite transmission is expected to be high, but in which temperatures are closely regulated. Our hypothesis explains features of human hairlessness-such as the marked sex difference in body hair, and its retention in the pubic regions-that are not explained by other theories.

  15. Impacts of globalisation on foodborne parasites.

    PubMed

    Robertson, Lucy J; Sprong, Hein; Ortega, Ynes R; van der Giessen, Joke W B; Fayer, Ron

    2014-01-01

    Globalisation is a manmade phenomenon encompassing the spread and movement of everything, animate and inanimate, material and intangible, around the planet. The intentions of globalisation may be worthy--but may also have unintended consequences. Pathogens may also be spread, enabling their establishment in new niches and exposing new human and animal populations to infection. The plethora of foodborne parasites that could be distributed by globalisation has only recently been acknowledged and will provide challenges for clinicians, veterinarians, diagnosticians, and everyone concerned with food safety. Globalisation may also provide the resources to overcome some of these challenges. It will facilitate sharing of methods and approaches, and establishment of systems and databases that enable control of parasites entering the global food chain.

  16. Transmission of Microsporidian Parasites of Mosquitoes.

    DTIC Science & Technology

    1983-06-01

    Microsporidia of the family Thelohaniidae are common parasites of mos- quitoes and certain other invertebrates . They have complex life cycles and exhibit...sporonts in electron micrographs. Spores from larvae and adult males appear short pyriform with a sharp point at the anterior end when viewed in fresh ...and an assay Jar, each containing about 500 ml of aged tap water . The experimental Jar contained one to many individuals of a candidate intermediate

  17. Infection with parasitic nematodes confounds vaccination efficacy.

    PubMed

    Urban, Joseph F; Steenhard, Nina R; Solano-Aguilar, Gloria I; Dawson, Harry D; Iweala, Onyinye I; Nagler, Cathryn R; Noland, Gregory S; Kumar, Nirbhay; Anthony, Robert M; Shea-Donohue, Terez; Weinstock, Joel; Gause, William C

    2007-08-19

    T helper (Th) cells produce signature cytokine patterns, induced largely by intracellular versus extracellular pathogens that provide the cellular and molecular basis for counter regulatory expression of protective immunity during concurrent infections. The production of IL-12 and IFN-gamma, for example, resulting from exposure to many bacterial, viral, and protozoan pathogens is responsible for Th1-derived protective responses that also can inhibit development of Th2-cells expressing IL-4-dependent immunity to extracellular helminth parasites and vice versa. In a similar manner, concurrent helminth infection alters optimal vaccine-induced responses in humans and livestock; however, the consequences of this condition have not been adequately studied especially in the context of a challenge infection following vaccination. Demands for new and effective vaccines to control chronic and emerging diseases, and the need for rapid deployment of vaccines for bio security concerns requires a systematic evaluation of confounding factors that limit vaccine efficacy. One common albeit overlooked confounder is the presence of gastrointestinal nematode parasites in populations of humans and livestock targeted for vaccination. This is particularly important in areas of the world were helminth infections are prevalent, but the interplay between parasites and emerging diseases that can be transmitted worldwide make this a global issue. In addition, it is not clear if the epidemic in allergic disease in industrialized countries substitutes for geohelminth infection to interfere with effective vaccination regimens. This presentation will focus on recent vaccination studies in mice experimentally infected with Heligmosomoides polygyrus to model the condition of gastrointestinal parasite infestation in mammalian populations targeted for vaccination. In addition, a large animal vaccination and challenge model against Mycoplasma hyopneumonia in swine exposed to Ascaris suum will provide

  18. Lung parasites of least weasels in Finland.

    PubMed

    Laakkonen, J; Sundell, J; Soveri, T

    1998-10-01

    Because of their constant exposure to normal rodent definitive hosts, least weasels (Mustela nivalis) were trapped in southern Finland in late fall 1994 and examined for lung parasites. Histological examination showed that 46% of the weasels (n = 46) were infected with adiaspores identified as Chrysosporium sp. Granulomas surrounding the adiaspores consisted of mostly unorganized layers of mononuclear cells. The adiaspores from least weasels were much smaller than those reported from their prey animals. Infection with Pneumocystis carinii also was found in two weasels.

  19. Fundamental factors determining the nature of parasite aggregation in hosts.

    PubMed

    Gourbière, Sébastien; Morand, Serge; Waxman, David

    2015-01-01

    The distribution of parasites in hosts is typically aggregated: a few hosts harbour many parasites, while the remainder of hosts are virtually parasite free. The origin of this almost universal pattern is central to our understanding of host-parasite interactions; it affects many facets of their ecology and evolution. Despite this, the standard statistical framework used to characterize parasite aggregation does not describe the processes generating such a pattern. In this work, we have developed a mathematical framework for the distribution of parasites in hosts, starting from a simple statistical description in terms of two fundamental processes: the exposure of hosts to parasites and the infection success of parasites. This description allows the level of aggregation of parasites in hosts to be related to the random variation in these two processes and to true host heterogeneity. We show that random variation can generate an aggregated distribution and that the common view, that encounters and success are two equivalent filters, applies to the average parasite burden under neutral assumptions but it does not apply to the variance of the parasite burden, and it is not true when heterogeneity between hosts is incorporated in the model. We find that aggregation decreases linearly with the number of encounters, but it depends non-linearly on parasite success. We also find additional terms in the variance of the parasite burden which contribute to the actual level of aggregation in specific biological systems. We have derived the formal expressions of these contributions, and these provide new opportunities to analyse empirical data and tackle the complexity of the origin of aggregation in various host-parasite associations.

  20. Fungal and Parasitic Infections of the Eye

    PubMed Central

    Klotz, Stephen A.; Penn, Christopher C.; Negvesky, Gerald J.; Butrus, Salim I.

    2000-01-01

    The unique structure of the human eye as well as exposure of the eye directly to the environment renders it vulnerable to a number of uncommon infectious diseases caused by fungi and parasites. Host defenses directed against these microorganisms, once anatomical barriers are breached, are often insufficient to prevent loss of vision. Therefore, the timely identification and treatment of the involved microorganisms are paramount. The anatomy of the eye and its surrounding structures is presented with an emphasis upon the association of the anatomy with specific infection of fungi and parasites. For example, filamentous fungal infections of the eye are usually due to penetrating trauma by objects contaminated by vegetable matter of the cornea or globe or, by extension, of infection from adjacent paranasal sinuses. Fungal endophthalmitis and chorioretinitis, on the other hand, are usually the result of antecedent fungemia seeding the ocular tissue. Candida spp. are the most common cause of endogenous endophthalmitis, although initial infection with the dimorphic fungi may lead to infection and scarring of the chorioretina. Contact lens wear is associated with keratitis caused by yeasts, filamentous fungi, and Acanthamoebae spp. Most parasitic infections of the eye, however, arise following bloodborne carriage of the microorganism to the eye or adjacent structures. PMID:11023963

  1. Invasion and Intracellular Survival by Protozoan Parasites

    PubMed Central

    Sibley, L. David

    2013-01-01

    Summary Intracellular parasitism has arisen only a few times during the long ancestry of protozoan parasites including in diverse groups such as microsporidians, kinetoplastids, and apicomplexans. Strategies used to gain entry differ widely from injection (e.g. microsporidians), active penetration of the host cell (e.g. Toxoplasma), recruitment of lysosomes to a plasma membrane wound (e.g. Trypanosoma cruzi), to host cell-mediated phagocytosis (e.g. Leishmania). The resulting range of intracellular niches is equally diverse ranging from cytosolic (e.g. T. cruzi) to residing within a nonfusigenic vacuole (e.g. Toxoplasma, Encephalitizoon) or a modified phagolysosome (e.g. Leishmania). These lifestyle choices influence access to nutrients, interaction with host cell signaling pathways, and detection by pathogen recognition systems. As such, intracellular life requires a repertoire of adaptations to assure entry-exit from the cell, as well as to thwart innate immune mechanisms and prevent clearance. Elucidating these pathways at the cellular and molecular level may identify key steps that can be targeted to reduce parasite survival or augment immunological responses and thereby prevent disease. PMID:21349087

  2. Parasitic zoonoses in Papua New Guinea.

    PubMed

    Owen, I L

    2005-03-01

    Relatively few species of zoonotic parasites have been recorded in humans in Papua New Guinea. A greater number of potentially zoonotic species, mostly nematodes, occur in animals but are yet to be reported from humans. Protozoa is the best represented group of those infecting man, with Giardia duodenalis, Cryptosporidium parvum, Cyclospora cayetanesis, Toxoplasma gondii, Sarcocystis spp., Entamoeba polecki, Balantidium coli and, possibly, Blastocystis hominis. The only zoonotic helminths infecting humans include the trematode Paragonimus westermani, the cestodes Hymenolepis nana, H. diminuta and the sparganum larva of Spirometra erinacea, and the nematodes Trichinella papuae and Angiostrongylus cantonensis and, possibly, Ascaris suum. Other groups represented are Acanthocephala (Macracanthorhynchus hirudinaceus)), insects (Chrysomya bezziana, Cimex sp., Ctenocephalides spp.), and mites (Leptotrombidium spp. and, possibly Sarcoptes scabiei, and Demodex sp.). One leech (Phytobdella lineata) may also be considered as being zoonotic. The paucity of zoonotic parasite species can be attributed to long historical isolation of the island of New Guinea and its people, and the absence until recent times of large placental mammals other than pig and dog. Some zoonotic helminths have entered the country with recent importation of domestic animals, in spite of quarantine regulations, and a few more (two cestodes, one nematode and one tick) are poised to enter from neighbouring countries, given the opportunity. Improvement in water supplies, human hygiene and sanitation would reduce the prevalence of many of these parasites, and thorough cooking of meat would lessen the risk of infection by some others.

  3. Bacterial, Fungal, Parasitic, and Viral Myositis

    PubMed Central

    Crum-Cianflone, Nancy F.

    2008-01-01

    Infectious myositis may be caused by a broad range of bacterial, fungal, parasitic, and viral agents. Infectious myositis is overall uncommon given the relative resistance of the musculature to infection. For example, inciting events, including trauma, surgery, or the presence of foreign bodies or devitalized tissue, are often present in cases of bacterial myositis. Bacterial causes are categorized by clinical presentation, anatomic location, and causative organisms into the categories of pyomyositis, psoas abscess, Staphylococcus aureus myositis, group A streptococcal necrotizing myositis, group B streptococcal myositis, clostridial gas gangrene, and nonclostridial myositis. Fungal myositis is rare and usually occurs among immunocompromised hosts. Parasitic myositis is most commonly a result of trichinosis or cystericercosis, but other protozoa or helminths may be involved. A parasitic cause of myositis is suggested by the travel history and presence of eosinophilia. Viruses may cause diffuse muscle involvement with clinical manifestations, such as benign acute myositis (most commonly due to influenza virus), pleurodynia (coxsackievirus B), acute rhabdomyolysis, or an immune-mediated polymyositis. The diagnosis of myositis is suggested by the clinical picture and radiologic imaging, and the etiologic agent is confirmed by microbiologic or serologic testing. Therapy is based on the clinical presentation and the underlying pathogen. PMID:18625683

  4. Host defense reinforces host–parasite cospeciation

    PubMed Central

    Clayton, Dale H.; Bush, Sarah E.; Goates, Brad M.; Johnson, Kevin P.

    2003-01-01

    Cospeciation occurs when interacting groups, such as hosts and parasites, speciate in tandem, generating congruent phylogenies. Cospeciation can be a neutral process in which parasites speciate merely because they are isolated on diverging host islands. Adaptive evolution may also play a role, but this has seldom been tested. We explored the adaptive basis of cospeciation by using a model system consisting of feather lice (Columbicola) and their pigeon and dove hosts (Columbiformes). We reconstructed phylogenies for both groups by using nuclear and mitochondrial DNA sequences. Both phylogenies were well resolved and well supported. Comparing these phylogenies revealed significant cospeciation and correlated evolution of host and parasite body size. The match in body size suggested that adaptive constraints limit the range of hosts lice can use. We tested this hypothesis by transferring lice among hosts of different sizes to simulate host switches. The results of these experiments showed that lice cannot establish viable populations on novel hosts that differ in size from the native host. To determine why size matters, we measured three components of louse fitness: attachment, feeding, and escape from host defense (preening). Lice could remain attached to, and feed on, hosts varying in size by an order of magnitude. However, they could not escape from preening on novel hosts that differed in size from the native host. Overall, our results suggest that host defense reinforces cospeciation in birds and feather lice by preventing lice from switching between hosts of different sizes. PMID:14673114

  5. When Parasites Are Good for Health: Cestode Parasitism Increases Resistance to Arsenic in Brine Shrimps

    PubMed Central

    Martínez-Haro, Mónica; Taggart, Mark A.; Lenormand, Thomas; Green, Andy J.

    2016-01-01

    Parasites and pollutants can both affect any living organism, and their interactions can be very important. To date, repeated studies have found that parasites and heavy metals or metalloids both have important negative effects on the health of animals, often in a synergistic manner. Here, we show for the first time that parasites can increase host resistance to metalloid arsenic, focusing on a clonal population of brine shrimp from the contaminated Odiel and Tinto estuary in SW Spain. We studied the effect of cestodes on the response of Artemia to arsenic (acute toxicity tests, 24h LC50) and found that infection consistently reduced mortality across a range of arsenic concentrations. An increase from 25°C to 29°C, simulating the change in mean temperature expected under climate change, increased arsenic toxicity, but the benefits of infection persisted. Infected individuals showed higher levels of catalase and glutathione reductase activity, antioxidant enzymes with a very important role in the protection against oxidative stress. Levels of TBARS were unaffected by parasites, suggesting that infection is not associated with oxidative damage. Moreover, infected Artemia had a higher number of carotenoid-rich lipid droplets which may also protect the host through the “survival of the fattest” principle and the antioxidant potential of carotenoids. This study illustrates the need to consider the multi-stress context (contaminants and temperature increase) in which host-parasite interactions occur. PMID:26938743

  6. Heightened exposure to parasites favors the evolution of immunity in brood parasitic cowbirds

    USGS Publications Warehouse

    Hahn, Caldwell; Reisen, William K.

    2011-01-01

    Immunologists and evolutionary biologists are interested in how the immune system evolves to fit an ecological niche. We studied the relationship between exposure to parasites and strength of immunity by investigating the response of two species of New World cowbirds (genus Molothrus, Icteridae), obligate brood parasites with contrasting life history strategies, to experimental arboviral infection. The South American shiny cowbird (M. bonariensis) is an extreme host-generalist that lays its eggs in the nests of >225 different avian species. The Central American bronzed cowbird (M. aeneus) is a relative host-specialist that lays its eggs preferentially in the nests of approximately 12 orioles in a single sister genus. West Nile virus provided a strong challenge and delineated immune differences between these species. The extreme host-generalist shiny cowbird, like the North American host-generalist, the brown-headed cowbird, showed significantly lower viremia to three arboviruses than related icterid species that were not brood parasites. The bronzed cowbird showed intermediate viremia. These findings support the interpretation that repeated exposure to a high diversity of parasites favors the evolution of enhanced immunity in brood parasitic cowbirds and makes them useful models for future studies of innate immunity.

  7. Can parasites halt the invader? Mermithid nematodes parasitizing the yellow-legged Asian hornet in France

    PubMed Central

    Zuccon, Dario; Rome, Quentin; Muller, Franck; Poinar Jr, George O.; Justine, Jean-Lou

    2015-01-01

    Since its introduction in France 10 years ago, the yellow-legged Asian bee-hawking hornet Vespa velutina has rapidly spread to neighboring countries (Spain, Portugal, Belgium, Italy, and Germany), becoming a new threat to beekeeping activities. While introduced species often leave behind natural enemies from their original home, which benefits them in their new environment, they can also suffer local recruitment of natural enemies. Three mermithid parasitic subadults were obtained from V. velutina adults in 2012, from two French localities. However, these were the only parasitic nematodes reported up to now in Europe, in spite of the huge numbers of nests destroyed each year and the recent examination of 33,000 adult hornets. This suggests that the infection of V. velutina by these nematodes is exceptional. Morphological criteria assigned the specimens to the genus Pheromermis and molecular data (18S sequences) to the Mermithidae, due to the lack of Pheromermis spp. sequences in GenBank. The species is probably Pheromermis vesparum, a parasite of social wasps in Europe. This nematode is the second native enemy of Vespa velutina recorded in France, after a conopid fly whose larvae develop as internal parasitoids of adult wasps and bumblebees. In this paper, we provide arguments for the local origin of the nematode parasite and its limited impact on hornet colony survival. We also clarify why these parasites (mermithids and conopids) most likely could not hamper the hornet invasion nor be used in biological control programs against this invasive species. PMID:26038716

  8. Can parasites halt the invader? Mermithid nematodes parasitizing the yellow-legged Asian hornet in France.

    PubMed

    Villemant, Claire; Zuccon, Dario; Rome, Quentin; Muller, Franck; Poinar, George O; Justine, Jean-Lou

    2015-01-01

    Since its introduction in France 10 years ago, the yellow-legged Asian bee-hawking hornet Vespa velutina has rapidly spread to neighboring countries (Spain, Portugal, Belgium, Italy, and Germany), becoming a new threat to beekeeping activities. While introduced species often leave behind natural enemies from their original home, which benefits them in their new environment, they can also suffer local recruitment of natural enemies. Three mermithid parasitic subadults were obtained from V. velutina adults in 2012, from two French localities. However, these were the only parasitic nematodes reported up to now in Europe, in spite of the huge numbers of nests destroyed each year and the recent examination of 33,000 adult hornets. This suggests that the infection of V. velutina by these nematodes is exceptional. Morphological criteria assigned the specimens to the genus Pheromermis and molecular data (18S sequences) to the Mermithidae, due to the lack of Pheromermis spp. sequences in GenBank. The species is probably Pheromermis vesparum, a parasite of social wasps in Europe. This nematode is the second native enemy of Vespa velutina recorded in France, after a conopid fly whose larvae develop as internal parasitoids of adult wasps and bumblebees. In this paper, we provide arguments for the local origin of the nematode parasite and its limited impact on hornet colony survival. We also clarify why these parasites (mermithids and conopids) most likely could not hamper the hornet invasion nor be used in biological control programs against this invasive species.

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

    PubMed

    Cohen, Joel E; Poulin, Robert; Lagrue, Clément

    2017-01-03

    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.

  10. Mitochondrial DNA suggests at least 11 origins of parasitism in angiosperms and reveals genomic chimerism in parasitic plants

    PubMed Central

    Barkman, Todd J; McNeal, Joel R; Lim, Seok-Hong; Coat, Gwen; Croom, Henrietta B; Young, Nelson D; dePamphilis, Claude W

    2007-01-01

    Background Some of the most difficult phylogenetic questions in evolutionary biology involve identification of the free-living relatives of parasitic organisms, particularly those of parasitic flowering plants. Consequently, the number of origins of parasitism and the phylogenetic distribution of the heterotrophic lifestyle among angiosperm lineages is unclear. Results Here we report the results of a phylogenetic analysis of 102 species of seed plants designed to infer the position of all haustorial parasitic angiosperm lineages using three mitochondrial genes: atp1, coxI, and matR. Overall, the mtDNA phylogeny agrees with independent studies in terms of non-parasitic plant relationships and reveals at least 11 independent origins of parasitism in angiosperms, eight of which consist entirely of holoparasitic species that lack photosynthetic ability. From these results, it can be inferred that modern-day parasites have disproportionately evolved in certain lineages and that the endoparasitic habit has arisen by convergence in four clades. In addition, reduced taxon, single gene analyses revealed multiple horizontal transfers of atp1 from host to parasite lineage, suggesting that parasites may be important vectors of horizontal gene transfer in angiosperms. Furthermore, in Pilostyles we show evidence for a recent host-to-parasite atp1 transfer based on a chimeric gene sequence that indicates multiple historical xenologous gene acquisitions have occurred in this endoparasite. Finally, the phylogenetic relationships inferred for parasites indicate that the origins of parasitism in angiosperms are strongly correlated with horizontal acquisitions of the invasive coxI group I intron. Conclusion Collectively, these results indicate that the parasitic lifestyle has arisen repeatedly in angiosperm evolutionary history and results in increasing parasite genomic chimerism over time. PMID:18154671

  11. Quantification of parasite load in clinical samples of leishmaniasis patients: IL-10 level correlates with parasite load in visceral leishmaniasis.

    PubMed

    Verma, Sandeep; Kumar, Rajesh; Katara, Gajendra Kumar; Singh, Laishram Chandreshwor; Negi, Narender Singh; Ramesh, V; Salotra, Poonam

    2010-04-09

    A rapid and accurate method to detect and quantify Leishmania parasite is urgently needed to facilitate early diagnosis of leishmaniasis and monitoring of antileishmania therapy. In this study, real-time assay was applied to estimate parasite load in clinical samples of visceral leishmaniasis (VL) and post kala-azar dermal leishmaniasis (PKDL) patients. The mean parasite load in blood of VL patients (n = 31) was 8,372 parasites/ml, while the mean parasite load in bone marrow aspirate (BMA) was 194,962 parasites/million nucleated cells (n = 12). Parasite load was undetectable after treatment with amphotericin B (n = 9) in VL, while a residual parasite burden was detected in 2 of 6 patients following treatment with sodium antimony gluconate. Further, circulating levels of IFN-gamma, TNF-alpha, IL-10, IL-6, IL-4 and IL-2 were analysed in VL patients (n = 29) by Cytometric Bead Array to evaluate correlation with parasitic load. Interestingly, IL-10 levels correlated significantly with parasite load (r = 0.82, P<0.0001). The mean parasite load in dermal lesions of PKDL patients was 9,502 parasites/microg tissue DNA at pre-treatment stage (n = 25), with no detectable parasites after therapy (n = 5). Parasite burden was distinctly higher (P<0.0001) in nodular lesions (n = 12) (19,586 parasites/microg tissue DNA) compared to papular/macular lesions (n = 13, 193 parasites/microg tissue DNA). Further, chronic PKDL lesions showed significantly (P = 0.0166) higher parasite load in comparison with acute lesions. Results indicate that chronic, nodular cases constitute the major parasite reservoir for anthroponotic transmission. Our results establish that the high parasite load in VL is strongly correlated with a high level of IL-10, implicating IL-10 as a marker of disease severity. The assay is applicable for diagnosis as well as prognosis of both VL and PKDL, providing a simple molecular tool to monitor the efficacy of antileishmanial drugs or vaccines.

  12. Parasite transmission in a natural multihost-multiparasite community.

    PubMed

    Auld, Stuart K J R; Searle, Catherine L; Duffy, Meghan A

    2017-05-05

    Understanding the transmission and dynamics of infectious diseases in natural communities requires understanding the extent to which the ecology, evolution and epidemiology of those diseases are shaped by alternative hosts. We performed laboratory experiments to test how parasite spillover affected traits associated with transmission in two co-occurring parasites: the bacterium Pasteuria ramosa and the fungus Metschnikowia bicuspidata Both parasites were capable of transmission from the reservoir host (Daphnia dentifera) to the spillover host (Ceriodaphnia dubia), but this occurred at a much higher rate for the fungus than the bacterium. We quantified transmission potential by combining information on parasite transmission and growth rate, and used this to compare parasite fitness in the two host species. For both parasites, transmission potential was lower in the spillover host. For the bacterium, virulence was higher in the spillover host. Transmission back to the original host was high for both parasites, with spillover influencing transmission rate of the fungus but not the bacterium. Thus, while inferior, the spillover host is not a dead-end for either parasite. Overall, our results demonstrate that the presence of multiple hosts in a community can have important consequences for disease transmission, and host and parasite fitness.This article is part of the themed issue 'Opening the black box: re-examining the ecology and evolution of parasite transmission'.

  13. Multiple parasitic crustacean infestation on belonid fish Strongylura strongylura

    PubMed Central

    Aneesh, Panakkool-Thamban; Sudha, Kappalli; Helna, Ameri Kottarathil; Anilkumar, Gopinathan; Trilles, Jean-Paul

    2014-01-01

    Abstract Simultaneous multiple infestation of parasitic crustacean species involving a cymothoid isopod, Cymothoa frontalis Milne Edward, 1840 and four species of copepods such as Lernanthropus tylosuri Richiardi, 1880, Caligodes lacinatus Kroyer, 1863, Bomolochus bellones Burmeister, 1833 and Dermoergasilus coleus Cressey & Collette, 1970 was frequently noticed on spot-tail needlefish, Strongylura strongylura (Belonidae) captured from the Malabar coast (Kerala, India) during the period from April 2011 to March 2012. All the 43 fishes (Strongylura strongylura) collected, were under the hyper-infection with parasitic crustaceans; a total of 388 parasitic crustaceans including 57 Cymothoa frontalis, 252 Lernanthropus tylosuri, 31 Caligodes lacinatus, 24 Bomolochus bellones and 32 Dermoergasilus coleus were recovered from the host fish. 4 members (9.30%) of host fish were under quadruple parasitism, in two different combinations. Seventeen (39.53%) host fishes showed triple parasitism and 20 (46.51%) members exhibited double parasitism, with four and five parasitic combinations respectively. Remaining two (4.65%) fishes were parasitized only by the copepod, Lernanthropus tylosuri. The infestations by all recovered parasitic crustaceans were highly site specific. The damage caused by the parasitic crustaceans was also discussed. PMID:25561846

  14. Parasite-mediated predation between native and invasive amphipods.

    PubMed Central

    MacNeil, Calum; Dick, Jaimie T A; Hatcher, Melanie J; Terry, Rebecca S; Smith, Judith E; Dunn, Alison M

    2003-01-01

    Parasites can structure biological communities directly through population regulation and indirectly by processes such as apparent competition. However, the role of parasites in the process of biological invasion is less well understood and mechanisms of parasite mediation of predation among hosts are unclear. Mutual predation between native and invading species is an important factor in determining the outcome of invasions in freshwater amphipod communities. Here, we show that parasites mediate mutual intraguild predation among native and invading species and may thereby facilitate the invasion process. We find that the native amphipod Gammarus duebeni celticus is host to a microsporidian parasite, Pleistophora sp. (new species), with a frequency of infection of 0-90%. However, the parasite does not infect three invading species, G. tigrinus, G. pulex and Crangonyx pseudogracilis. In field and laboratory manipulations, we show that the parasite exhibits cryptic virulence: the parasite does not affect host fitness in single-species populations, but virulence becomes apparent when the native and invading species interact. That is, infection has no direct effect on G. d. celticus survivorship, size or fecundity; however, in mixed-species experiments, parasitized natives show a reduced capacity to prey on the smaller invading species and are more likely to be preyed upon by the largest invading species. Thus, by altering dominance relationships and hierarchies of mutual predation, parasitism strongly influences, and has the potential to change, the outcome of biological invasions. PMID:12816645

  15. Host species exploitation and discrimination by animal parasites.

    PubMed

    Forbes, Mark R; Morrill, André; Schellinck, Jennifer

    2017-05-05

    Parasite species often show differential fitness on different host species. We developed an equation-based model to explore conditions favouring host species exploitation and discrimination. In our model, diploid infective stages randomly encountered hosts of two species; the parasite's relative fitness in exploiting each host species, and its ability to discriminate between them, was determined by the parasite's genotype at two independent diallelic loci. Relative host species frequency determined allele frequencies at the exploitation locus, whereas differential fitness and combined host density determined frequency of discrimination alleles. The model predicts instances where populations contain mixes of discriminatory and non-discriminatory infective stages. Also, non-discriminatory parasites should evolve when differential fitness is low to moderate and when combined host densities are low, but not so low as to cause parasite extinction. A corollary is that parasite discrimination (and host-specificity) increases with higher combined host densities. Instances in nature where parasites fail to discriminate when differential fitness is extreme could be explained by one host species evolving resistance, following from earlier selection for parasite non-discrimination. Similar results overall were obtained for haploid extensions of the model. Our model emulates multi-host associations and has implications for understanding broadening of host species ranges by parasites.This article is part of the themed issue 'Opening the black box: re-examining the ecology and evolution of parasite transmission'.

  16. Mechanisms of CNS invasion and damage by parasites.

    PubMed

    Kristensson, Krister; Masocha, Willias; Bentivoglio, Marina

    2013-01-01

    Invasion of the central nervous system (CNS) is a most devastating complication of a parasitic infection. Several physical and immunological barriers provide obstacles to such an invasion. In this broad overview focus is given to the physical barriers to neuroinvasion of parasites provided at the portal of entry of the parasites, i.e., the skin and epithelial cells of the gastrointestinal tract, and between the blood and the brain parenchyma, i.e., the blood-brain barrier (BBB). A description is given on how human pathogenic parasites can reach the CNS via the bloodstream either as free-living or extracellular parasites, by embolization of eggs, or within red or white blood cells when adapted to intracellular life. Molecular mechanisms are discussed by which parasites can interact with or pass across the BBB. The possible targeting of the circumventricular organs by parasites, as well as the parasites' direct entry to the brain from the nasal cavity through the olfactory nerve pathway, is also highlighted. Finally, examples are given which illustrate different mechanisms by which parasites can cause dysfunction or damage in the CNS related to toxic effects of parasite-derived molecules or to immune responses to the infection.

  17. Overview on the effects of parasites on fish health

    USGS Publications Warehouse

    Iwanowicz, D.D.; Cipriano, R.C.; Bruckner, A.W.; Shchelkunov, I.S.

    2011-01-01

    It is believed by many that parasites are only as important as the fish they infect. Parasites are ubiquitous, primarily surviving in a dynamic equilibrium with their host(s) and they are often overlooked in fish health assessments. Changes in the environment, both anthropogenic and environmental, can alter the parasite/host equilibrium and cause disease or mortality in fish. Therefore it is imperative that we have knowledge of both parasites and parasitic communities within a given population. When fish kills occur, it can often be associated with changes in parasite density and community composition. Often the damage associated with these fish is relative to the rate of infestation with the parasite; a fish that is lightly infected will show few signs of the parasite, while a heavily infected fish may become physiologically impaired and even die. Parasites can cause mechanical damage (fusion of gill lamellae, tissue replacement), physiological damage (cell proliferation, immunomodulation, detrimental behavioral responses, altered growth) and reproductive damage. As parasitism is the most common lifestyle on the planet, understanding its role in the environment may help researchers understand changes in a given fish population or stream ecosystem.

  18. Evaluating parasite densities and estimation of parameters in transmission systems.

    PubMed

    Heinzmann, D; Torgerson, P R

    2008-09-01

    Mathematical modelling of parasite transmission systems can provide useful information about host parasite interactions and biology and parasite population dynamics. In addition good predictive models may assist in designing control programmes to reduce the burden of human and animal disease. Model building is only the first part of the process. These models then need to be confronted with data to obtain parameter estimates and the accuracy of these estimates has to be evaluated. Estimation of parasite densities is central to this. Parasite density estimates can include the proportion of hosts infected with parasites (prevalence) or estimates of the parasite biomass within the host population (abundance or intensity estimates). Parasite density estimation is often complicated by highly aggregated distributions of parasites within the hosts. This causes additional challenges when calculating transmission parameters. Using Echinococcus spp. as a model organism, this manuscript gives a brief overview of the types of descriptors of parasite densities, how to estimate them and on the use of these estimates in a transmission model.

  19. Life history strategy influences parasite responses to habitat fragmentation.

    PubMed

    Froeschke, Götz; van der Mescht, Luther; McGeoch, Melodie; Matthee, Sonja

    2013-12-01

    Anthropogenic habitat use is a major threat to biodiversity and is known to increase the abundance of generalist host species such as rodents, which are regarded as potential disease carriers. Parasites have an intimate relationship with their host and the surrounding environment and it is expected that habitat fragmentation will affect parasite infestation levels. We investigated the effect of habitat fragmentation on the ecto- and endoparasitic burdens of a broad niche small mammal, Rhabdomys pumilio, in the Western Cape Province, South Africa. Our aim was to look at the effects of fragmentation on different parasite species with diverse life history characteristics and to determine whether general patterns can be found. Sampling took place within pristine lowland (Fynbos/Renosterveld) areas and at fragmented sites surrounded and isolated by agricultural activities. All arthropod ectoparasites and available gastrointestinal endoparasites were identified. We used conditional autoregressive models to investigate the effects of habitat fragmentation on parasite species richness and abundance of all recovered parasites. Host density and body size were larger in the fragments. Combined ecto- as well as combined endoparasite taxa showed higher parasite species richness in fragmented sites. Parasite abundance was generally higher in the case of R. pumilio individuals in fragmented habitats but it appears that parasites that are more permanently associated with the host's body and those that are host-specific show the opposite trend. Parasite life history is an important factor that needs to be considered when predicting the effects of habitat fragmentation on parasite and pathogen transmission.

  20. 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

  1. Host species exploitation and discrimination by animal parasites

    PubMed Central

    Forbes, Mark R.; Morrill, André; Schellinck, Jennifer

    2017-01-01

    Parasite species often show differential fitness on different host species. We developed an equation-based model to explore conditions favouring host species exploitation and discrimination. In our model, diploid infective stages randomly encountered hosts of two species; the parasite's relative fitness in exploiting each host species, and its ability to discriminate between them, was determined by the parasite's genotype at two independent diallelic loci. Relative host species frequency determined allele frequencies at the exploitation locus, whereas differential fitness and combined host density determined frequency of discrimination alleles. The model predicts instances where populations contain mixes of discriminatory and non-discriminatory infective stages. Also, non-discriminatory parasites should evolve when differential fitness is low to moderate and when combined host densities are low, but not so low as to cause parasite extinction. A corollary is that parasite discrimination (and host-specificity) increases with higher combined host densities. Instances in nature where parasites fail to discriminate when differential fitness is extreme could be explained by one host species evolving resistance, following from earlier selection for parasite non-discrimination. Similar results overall were obtained for haploid extensions of the model. Our model emulates multi-host associations and has implications for understanding broadening of host species ranges by parasites. This article is part of the themed issue ‘Opening the black box: re-examining the ecology and evolution of parasite transmission’. PMID:28289258

  2. Shiny cowbird parasitism in two avian communities in Puerto Rico

    USGS Publications Warehouse

    Wiley, J.W.

    1985-01-01

    The shiny cowbird (M. bonariensis), a brood parasite, has recently expanded its range from South America to Puerto Rico via the Lesser Antilles. This species is a host generalist and, on reaching Puerto Rico, encounteed avian species with no history of social parasitism. In mangrove habitat study areas, 42% of the resident non-raptorial land bird species were parasitized. Some species were heavily parasitized; e.g., yellow warbler (Dendroica petechia), 76% of nests parasitized black-whiskered vireo (Vireo altiloquus), 82%, Puerto Rican flycatcher (Myiarchus antillarum), 85%, yellow-shouldered blackbird (Agelaius xanthomus), 95%, troupial (Icterus icterus), 100%, black-cowled oriole (I. dominicensis), 100%. Others suffered low rates of parasitism (2-17% of nests examined); e.g., gray kingbird (Tyrannus dominicensis), red-legged thrush (Turdus plumbeus), bronze mannikin (Lonchura cucullata), northern mockingbird (Mimus polyglottos), greater antillean grackle (Quiscalus niger). Cowbird parasitism affected hosts by depressing nest success an average of 41% below non-parasitized nests and reducing host productivity. Parasitized host nests hatched 12% fewer eggs an fledged 67% fewer of their own chicks than non-parasitized pairs.

  3. Parasite communities of freshwater fish under flood conditions.

    PubMed

    Kadlec, Dusan; Simková, Andrea; Jarkovský, Jirí; Gelnar, Milan

    2003-03-01

    The parasite communities of the freshwater fish species roach ( Rutilus rutilus), bitterling ( Rhodeus sericeus amarus) and perch ( Perca fluviatilis) were investigated during a major flood. Differences in parasite community structure due to changes in the host environment were expected. We therefore tested for differences in parasite species abundance and diversity as a consequence of the flood. Potential changes in parasite community structure due to seasonal influences were also considered. We found differences in the composition of parasite species and the proportion of ecto- and endoparasites in the three host species. The parasite community of roach was richer in species than those of perch and bitterling. Roach harboured more ectoparasite than endoparasite species. Parasite communities of both perch and bitterling were richer in endoparasite species and had a lower number of ectoparasite species. Parasite communities of the three different host species responded in different ways to environmental change. Considering all parasite species, no effect of either season or flood was found on the species diversity in either perch or bitterling. The flood caused an increase in the parasite species diversity in roach. For roach and perch, higher parasite abundance were found before the flood compared to after flood. However, no difference was found between the different seasons after the flood. By contrast, bitterling had the highest parasite abundance in the season after the flood. When analysing ecto- and endoparasites separately, a decrease in ectoparasite abundance was found in roach and perch, probably related to the flood, and due mainly to a decrease in monogenean species. A significant increase in the abundance of endoparasites was found in perch. In bitterling, the post-flood increase in ectoparasites was due to a high abundance of Gyrodactylus spp. We conclude that the parasite communities of the three fish species responded in different ways to the flood

  4. 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

  5. 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.

  6. "Parasite-induced aposematism" protects entomopathogenic nematode parasites against invertebrate enemies.

    PubMed

    Jones, Rebecca S; Fenton, Andy; Speed, Michael P

    2016-01-01

    Aposematism is a well-known strategy in which prey defend themselves from predation by pairing defenses such as toxins, with warning signals that are often visually conspicuous color patterns. Here, we examine the possibility that aposematism can be induced in a host by colonies of infectious parasites in order to protect the parasites from the consequences of attacks on the host. Earlier studies show that avian predators are reluctant to feed on carcasses of host prey that are infected with the entomopathogenic nematode, Heterorhabditis bacteriophora. As the age of infection increases, the parasites kill and preserve the host and subsequently cause its color to change, becoming bright pink then red. Nematode colonies in dead hosts may also be vulnerable, however, to nocturnally active foragers that do not use vision in prey detection. Here, then we test a novel hypothesis that the nematode parasites also produce a warning odor, which functions to repel nocturnally active predators (in this case, the beetle Pterostichus madidus). We show that beetles decrease their feeding on infected insect prey as the age of infection increases and that olfactory cues associated with the infections are effective mechanisms for deterring beetle predation, even at very early stages of infection. We propose that "parasite-induced aposematism" from the nematodes serves to replace the antipredator defenses of the recently killed host. Because sessile carcasses are exposed to a greater range of predators than the live hosts, several alternative defense mechanisms are required to protect the colony, hence aposematic signals are likely diverse in such "parasite-induced aposematism."

  7. Aggregation of Infective Stages of Parasites as an Adaptation and Its Implications for the Study of Parasite-Host Interactions.

    PubMed

    Morrill, André; Forbes, Mark R

    2016-02-01

    The causes and consequences of aggregation among conspecifics have received much attention. For infecting macroparasites, causes include variation among hosts in susceptibility and whether infective stages are aggregated in the environment. Here, we link these two phenomena and explore whether aggregation of infective stages in the environment is adaptive to parasites encountering host condition-linked defenses and what effect such aggregations have for parasite-host interactions. Using simulation models, we show that parasite fitness is increased by aggregates attacking a host, particularly when investment into defenses is high. The fitness benefit of aggregation remains despite inclusion of factors that should curb the benefits of aggregation, namely, mortality of low-condition hosts (those hosts expected to be most susceptible to parasitism) and costs of high coinfection. For sample sizes common in studies, aggregation of infective stages reduces the likelihood of detecting host condition-parasitism relations, even when host condition is the only other factor in models affecting parasitism. Thus, it is not surprising that the expected inverse relations between host condition and parasitism, commonly a premise in studies of parasite-host interactions, are inconsistently found. An understanding of how parasites encounter hosts is thus needed for developing theory for parasite-host ecological and evolutionary interactions.

  8. Functional genomics of a generalist parasitic plant: Laser microdissection of host-parasite interface reveals host-specific patterns of parasite gene expression

    PubMed Central

    2013-01-01

    Background Orobanchaceae is the only plant family with members representing the full range of parasitic lifestyles plus a free-living lineage sister to all parasitic lineages, Lindenbergia. A generalist member of this family, and an important parasitic plant model, Triphysaria versicolor regularly feeds upon a wide range of host plants. Here, we compare de novo assembled transcriptomes generated from laser micro-dissected tissues at the host-parasite interface to uncover details of the largely uncharacterized interaction between parasitic plants and their hosts. Results The interaction of Triphysaria with the distantly related hosts Zea mays and Medicago truncatula reveals dramatic host-specific gene expression patterns. Relative to above ground tissues, gene families are disproportionally represented at the interface including enrichment for transcription factors and genes of unknown function. Quantitative Real-Time PCR of a T. versicolor β-expansin shows strong differential (120x) upregulation in response to the monocot host Z. mays; a result that is concordant with our read count estimates. Pathogenesis-related proteins, other cell wall modifying enzymes, and orthologs of genes with unknown function (annotated as such in sequenced plant genomes) are among the parasite genes highly expressed by T. versicolor at the parasite-host interface. Conclusions Laser capture microdissection makes it possible to sample the small region of cells at the epicenter of parasite host interactions. The results of our analysis suggest that T. versicolor’s generalist strategy involves a reliance on overlapping but distinct gene sets, depending upon the host plant it is parasitizing. The massive upregulation of a T. versicolor β-expansin is suggestive of a mechanism for parasite success on grass hosts. In this preliminary study of the interface transcriptomes, we have shown that T. versicolor, and the Orobanchaceae in general, provide excellent opportunities for the

  9. Lysine Deacetylase Inhibitors in Parasites: Past, Present, and Future Perspectives.

    PubMed

    Hailu, Gebremedhin S; Robaa, Dina; Forgione, Mariantonietta; Sippl, Wolfgang; Rotili, Dante; Mai, Antonello

    2017-03-15

    Current therapies for human parasite infections rely on a few drugs, most of which have severe side effects, and their helpfulness is being seriously compromised by the drug resistance problem. Globally, this is pushing discovery research of antiparasitic drugs toward new agents endowed with new mechanisms of action. By using a "drug repurposing" strategy, histone deacetylase inhibitors (HDACi), which are presently clinically approved for cancer use, are now under investigation for various parasite infections. Because parasitic Zn(2+)- and NAD(+)-dependent HDACs play crucial roles in the modulation of parasite gene expression and many of them are pro-survival for several parasites under various conditions, they are now emerging as novel potential antiparasitic targets. This Perspective summarizes the state of knowledge of HDACi (both class I/II HDACi and sirtuin inhibitors) targeted to the main human parasitic diseases (schistosomiasis, malaria, trypanosomiasis, leishmaniasis, and toxoplasmosis) and provides visions into the main issues that challenge their development as antiparasitic agents.

  10. Highly rearranged mitochondrial genome in Nycteria parasites (Haemosporidia) from bats

    PubMed Central

    Karadjian, Gregory; Hassanin, Alexandre; Saintpierre, Benjamin; Gembu Tungaluna, Guy-Crispin; Ariey, Frederic; Ayala, Francisco J.; Landau, Irene; Duval, Linda

    2016-01-01

    Haemosporidia parasites have mostly and abundantly been described using mitochondrial genes, and in particular cytochrome b (cytb). Failure to amplify the mitochondrial cytb gene of Nycteria parasites isolated from Nycteridae bats has been recently reported. Bats are hosts to a diverse and profuse array of Haemosporidia parasites that remain largely unstudied. There is a need to obtain more molecular data from chiropteran parasites. Such data would help to better understand the evolutionary history of Haemosporidia, which notably include the Plasmodium parasites, malaria’s agents. We use next-generation sequencing to obtain the complete mitochondrial genome of Nycteria parasites from African Nycteris grandis (Nycteridae) and Rhinolophus alcyone (Rhinolophidae) and Asian Megaderma spasma (Megadermatidae). We report four complete mitochondrial genomes, including two rearranged mitochondrial genomes within Haemosporidia. Our results open outlooks into potentially undiscovered Haemosporidian diversity. PMID:27528689

  11. Parasitic diseases in travelers: a focus on therapy.

    PubMed

    Showler, Adrienne J; Wilson, Mary E; Kain, Kevin C; Boggild, Andrea K

    2014-04-01

    Parasitic infections are an important cause of illness among returned travelers, and can lead to considerable morbidity and, in some cases, mortality. The complexity of parasitic life cycles and geographic specificities can present diagnostic challenges, particularly in non-endemic settings to which most travelers return for care. Clinical manifestations reflect the diverse taxonomy and pathogenesis of parasites, and appropriate diagnosis and management therefore necessitate a high index of suspicion of parasitic illnesses. Much of our knowledge surrounding management of parasitic infections in travelers is extrapolated from evidence derived in endemic populations, or is based on expert opinion and case series. We herein provide an overview of parasitic diseases of short-term travelers, and summarize current therapeutic strategies for each illness.

  12. Parasite-mediated reduction in fecundity of mountain hares.

    PubMed Central

    Newey, Scott; Thirgood, Simon

    2004-01-01

    Mountain hare populations in Scotland exhibit regular 10 year fluctuations in abundance. Simple models of host-parasite population dynamics suggest that parasite-mediated reductions in host fecundity can cause a transition from stable to cyclic host population dynamics. We tested the hypothesis that parasites reduce hare fecundity by experimentally reducing parasite burdens and recording female survival, body condition and fecundity. We captured 41 adult female hares in October 2002; 22 were treated with Ivermectin to remove parasites and 19 were left untreated as controls. The treated and untreated hares were culled in May 2003 together with a second control group of nine unhandled hares. Treatment with Ivermectin significantly reduced the abundance of Trichostrongylus retortaeformis and increased-the fecundity of the hares, but had no measurable effect on body condition or over-winter survival. These results are consistent with the hypothesis that parasites may be a contributory cause of cycles in populations of mountain hares. PMID:15801590

  13. Trematode parasites infect or die in snail hosts

    PubMed Central

    King, Kayla C.; Jokela, Jukka; Lively, Curtis M.

    2011-01-01

    The Red Queen hypothesis is based on the assumption that parasites must genetically match their hosts to infect them successfully. If the parasites fail, they are assumed to be killed by the host's immune system. Here, we tested this using sympatric (mostly susceptible) and allopatric (mostly resistant) populations of a freshwater snail and its trematode parasite. We determined whether parasites which do not infect are either killed or passed through the host's digestive tract and remain infectious. Our results show that parasites do not get a second chance: they either infect or are killed by the host. The results suggest strong selection against parasites that are not adapted to local host genotypes. PMID:20961880

  14. Plastic behaviors in hosts promote the emergence of retaliatory parasites

    PubMed Central

    Chakra, Maria Abou; Hilbe, Christian; Traulsen, Arne

    2014-01-01

    Mafia like behavior, where individuals cooperate under the threat of punishment, occurs not only in humans, but is also observed in several animal species. Observations suggest that avian hosts tend to accept a certain degree of parasitism in order to avoid retaliating punishment from the brood parasite. To understand under which conditions it will be beneficial for a host to cooperate, we model the interaction between hosts and parasites as an evolutionary game. In our model, the host's behavior is plastic, and thus, its response depends on the previous interactions with the parasite. We find that such learned behavior in turn is crucial for the evolution of retaliating parasites. The abundance of this kind of mafia behavior oscillates in time and does not settle to an equilibrium. Our results suggest that retaliation is a mechanism for the parasite to evade specialization and to induce acceptance by the host. PMID:24589512

  15. Parasitic rotation evaluation and avoidance of 3-UPU parallel mechanism

    NASA Astrophysics Data System (ADS)

    Qu, Haibo; Fang, Yuefa; Guo, Sheng

    2012-06-01

    Based on the prototype of 3-UPU (universal-prismatic-universal joint) parallel mechanism proposed by Tsai [1], the parasitic rotation evaluation is performed and calculated the bound of instability of SNU (Seoul National University) 3-UPU parallel mechanism. Through analysis of the terminal constraint system of the 3-UPU parallel mechanism, the equation about the parasitic rotation and limited clearance is presented. Then the norm of possible parasitic rotation is employed to evaluate the mechanism stability with limited clearance. The higher this number the worst is the pose, the lower it is the best it is. And the contour atlas of parasitic rotation is obtained, which can be used for further analysis and design. With the practice experiment result of SUN 3-UPU parallel mechanism, we find it's bound of instability, which indicates there will appear the parasitic rotation when the number exceeds the bound. Finally, the method for avoidance of possible parasitic motions is presented by adding redundantly actuated limbs.

  16. Carotenoid-based bill colour is an integrative signal of multiple parasite infection in blackbird

    NASA Astrophysics Data System (ADS)

    Biard, Clotilde; Saulnier, Nicolas; Gaillard, Maria; Moreau, Jérôme

    2010-11-01

    In the study of parasite-mediated sexual selection, there has been controversial evidence for the prediction that brighter males should have fewer parasites. Most of these studies have focused on one parasite species. Our aim was to investigate the expression of carotenoid-based coloured signals in relation to patterns of multiple parasite infections, to determine whether colour reflects parasite load of all parasite species, or whether different relationships might be found when looking at each parasite species independently. We investigated the relationship between bill colour, body mass and plasma carotenoids and parasite load (feather chewing lice, blood parasite Plasmodium sp., intestinal parasites cestodes and coccidia) in the blackbird ( Turdus merula). Bill colour on its own appeared to be a poor predictor of parasite load when investigating its relationships with individual parasite species. Variation in parasite intensities at the community level was summarised using principal component analysis to derive synthetic indexes of relative parasite species abundance and absolute parasite load. The relative abundance of parasite species was strongly related to bill colour, plasma carotenoid levels and body mass: birds with relatively more cestodes and chewing lice and relatively less Plasmodium and coccidia had a more colourful bill, circulated more carotenoids and were heavier. These results suggest that bill colour more accurately reflects the relative intensities of parasite infection, rather than one-by-one relationships with parasites or absolute parasite burden. Investigating patterns of multiple parasite infection would thus improve our understanding of the information conveyed by coloured signals on parasite load.

  17. [Parasite-host relationships and treatment].

    PubMed

    Vuitton, Dominique-Angèle; Mantion, Georges; Bartholomot, Brigitte; Giraudoux, Patrick; Bresson-Hadni, Solange

    2008-01-01

    Alveolar echinococcosis (AE) is a parasitic disease caused by intrahepatic growth of the larval stage of the cestode Echinococcus multilocularis. The main definitive host in Europe is the fox. The adult worms live in the fox intestine and their oncospheres are disseminated by faeces. Wolves, dogs and cats may also serve as definitive hosts. Small rodents--especially voles in Europe and small lagomorphs in Asia--are the natural intermediate hosts. The tumour-like larva is composed of multiple vesicles which produce protoscoleces, the fertile stage of the E. multilocularis metacestode. Carnivores are infected by preying on infected rodents. Like rodents, humans are intermediate hosts and are infected either by eating uncooked vegetables and berries contaminated by faeces of infected carnivores, or by touching such animals. Humans are naturally resistant to metacestode development. Genetic characteristics are involved in susceptibility/resistance to E. multilocularis metacestodes. In humans and other intermediate animal hosts, immune suppression enhances parasite growth, which is normally controlled by cytotoxic mechanisms and delayed-type hypersensitivity. Tolerance of E. multilocularis is due in part to parasite characteristics (especially carbohydrate antigens of the laminated layer) and in part to the "anti-inflammatory/tolerogenic" cytokines IL-10 and TGF-beta. Treatment with interferon-a restores a cytokine balance favorable to the host and might be a new therapeutic option for AE patients. Vaccination is a scientifically sound but economically and politically Utopian means of preventing the disease. Prevention thus relies on simple lifestyle measures: cooking potentially contaminated food, regular treatment of domestic animals with praziquantel, and precautions when touching potentially infected definitive hosts (foxes and dogs).

  18. Foodborne parasites from wildlife: how wild are they?

    PubMed

    Kapel, Christian M O; Fredensborg, Brian L

    2015-04-01

    The majority of wild foods consumed by humans are sourced from intensively managed or semi-farmed populations. Management practices inevitably affect wildlife density and habitat characteristics, which are key elements in the transmission of parasites. We consider the risk of transmission of foodborne parasites to humans from wildlife maintained under natural or semi-natural conditions. A deeper understanding will be useful in counteracting foodborne parasites arising from the growing industry of novel and exotic foods.

  19. [Intestinal and hepatic parasitic diseases: diagnosis and treatment].

    PubMed

    Gétaz, L; Chappuis, F; Loutan, L

    2007-05-16

    Intestinal parasites represent an important burden of disease mainly in developing countries. Physicians practicing in Europe can be exposed to these diseases, mainly seen in immigrants or travellers returning from tropical countries. Several parasitic diseases remain ubiquitous and can be contracted in developed countries. Most often, parasitic infections cause no or only few symptoms, but some can lead to serious disease in immuno-compromised patients. Diagnostic procedures and treatments available are discussed.

  20. Revealing parasite influence in metabolic pathways in Apicomplexa infected patients

    PubMed Central

    2010-01-01

    Background As an obligate intracellular parasite, Apicomplexa interacts with the host in the special living environment, competing for energy and nutrients from the host cells by manipulating the host metabolism. Previous studies of host-parasite interaction mainly focused on using cellular and biochemical methods to investigate molecular functions in metabolic pathways of parasite infected hosts. Computational approaches taking advantage of high-throughput biological data and topology of metabolic pathways have a great potential in revealing the details and mechanism of parasites-to-host interactions. A new analytical method was designed in this work to study host-parasite interactions in human cells infected with Plasmodium falciparum and Cryptosporidium parvum. Results We introduced a new method that analyzes the host metabolic pathways in divided parts: host specific subpathways and host-parasite common subpathways. Upon analysis on gene expression data from cells infected by Plasmodium falciparum or Cryptosporidium parvum, we found: (i) six host-parasite common subpathways and four host specific subpathways were significantly altered in plasmodium infected human cells; (ii) plasmodium utilized fatty acid biosynthesis and elongation, and Pantothenate and CoA biosynthesis to obtain nutrients from host environment; (iii) in Cryptosporidium parvum infected cells, most of the host-parasite common enzymes were down-regulated, whereas the host specific enzymes up-regulated; (iv) the down-regulation of common subpathways in host cells might be caused by competition for the substrates and up-regulation of host specific subpathways may be stimulated by parasite infection. Conclusion Results demonstrated a significantly coordinated expression pattern between the two groups of subpathways. The method helped expose the impact of parasite infection on host cell metabolism, which was previously concealed in the pathway enrichment analysis. Our approach revealed detailed

  1. Selection against somatic parasitism can maintain allorecognition in fungi.

    PubMed

    Czárán, Tamas; Hoekstra, Rolf F; Aanen, Duur K

    2014-12-01

    Fusion between multicellular individuals is possible in many organisms with modular, indeterminate growth, such as marine invertebrates and fungi. Although fusion may provide various benefits, fusion usually is restricted to close relatives by allorecognition, also called heterokaryon or somatic incompatibility in fungi. A possible selective explanation for allorecognition is protection against somatic parasites. Such mutants contribute less to colony functions but more to reproduction. However, previous models testing this idea have failed to explain the high diversity of allorecognition alleles in nature. These models did not, however, consider the possible role of spatial structure. We model the joint evolution of allorecognition and somatic parasitism in a multicellular organism resembling an asexual ascomycete fungus in a spatially explicit simulation. In a 1000-by-1000 grid, neighbouring individuals can fuse, but only if they have the same allotype. Fusion with a parasitic individual decreases the total reproductive output of the fused individuals, but the parasite compensates for this individual-level fitness reduction by a disproportional share of the offspring. Allorecognition prevents the invasion of somatic parasites, and vice versa, mutation towards somatic parasitism provides the selective conditions for extensive allorecognition diversity. On the one hand, if allorecognition diversity did not build up fast enough, somatic parasites went to fixation; conversely, once parasites had gone to fixation no allorecognition diversity built up. On the other hand, the mere threat of parasitism could select for high allorecognition diversity, preventing invasion of somatic parasites. Moderate population viscosity combined with weak global dispersal was optimal for the joint evolution of allorecognition and protection against parasitism. Our results are consistent with the widespread occurrence of allorecognition in fungi and the low degree of somatic parasitism

  2. Ultrastructure of cyst differentiation in parasitic protozoa.

    PubMed

    Chávez-Munguía, Bibiana; Omaña-Molina, Maritza; González-Lázaro, Mónica; González-Robles, Arturo; Cedillo-Rivera, Roberto; Bonilla, Patricia; Martínez-Palomo, Adolfo

    2007-05-01

    Cysts represent a phase in the life cycle of biphasic parasitic protozoa that allow them to survive under adverse environmental conditions. Two events are required for the morphological differentiation from trophozoite to cyst and from cyst to trophozoite: the encystation and excystation processes. In this paper, we present a review of the ultrastructure of the encystation and excystation processes in Entamoeba invadens, Acanthamoeba castellanii, and Giardia lamblia. The comparative electron microscopical observations of these events here reported provide a morphological background to better understand recent advances in the biochemistry and molecular biology of the differentiation phenomena in these microorganisms.

  3. Some diseases and parasites of captive woodcocks

    USGS Publications Warehouse

    Locke, L.N.; Stickel, W.H.; Geis, S.A.

    1965-01-01

    Observations were made concerning the diseases and parasites of a group of woodcocks (Philohela minor) caught in Massachusetts in the summer of 1960 and kept in captivity in Maryland, and of another group caught and kept in Louisiana in the winter of 1960-61. Bumblefoot, a granulomatous swelling of the foot caused by Micrococcus sp., is reported for woodcocks for the first time. Six of 31 woodcocks were infected with a renal coccidium of an undetermined species. Tetrameres sp. was found in 4 of 31 birds examined. Sarcocystis was found in one bird. Aerosaculitis was found in several.

  4. Erythrocytic vacuolar rafts induced by malaria parasites.

    PubMed

    Haldar, K; Samuel, B U; Mohandas, N; Harrison, T; Hiller, N L

    2001-03-01

    Studies in the past year displaced long-standing dogmas and provided many new molecular insights into how proteins and solutes move between the erythrocyte plasma membrane and the malarial vacuole. Highlights include a demonstration that (1) detergent-resistant membrane (DRM) rafts exist in the red cell membrane and their resident proteins are detected as rafts in the plasmodial vacuole, (2) a voltage-gated channel in the infected red cell membrane mediates uptake of extracellular nutrient solutes, and (3) intraerythrocytic membranes transport a parasite-encoded adherence antigen to the red cell surface.

  5. Host social behavior and parasitic infection: A multifactorial approach

    USGS Publications Warehouse

    Ezenwa, V.O.

    2004-01-01

    I examined associations between several components of host social organization, including group size and gregariousness, group stability, territoriality and social class, and gastrointestinal parasite load in African bovids. At an intraspecific level, group size was positively correlated with parasite prevalence, but only when the parasite was relatively host specific and only among host species living in stable groups. Social class was also an important predictor of infection rates. Among gazelles, territorial males had higher parasite intensities than did either bachelor males or females and juveniles, suggesting that highly territorial individuals may be either more exposed or more susceptible to parasites. Associations among territoriality, grouping, and parasitism were also found across taxa. Territorial host genera were more likely to be infected with strongyle nematodes than were nonterritorial hosts, and gregarious hosts were more infected than were solitary hosts. Analyses also revealed that gregariousness and territoriality had an interactive effect on individual parasite richness, whereby hosts with both traits harbored significantly more parasite groups than did hosts with only one or neither trait. Overall, study results indicate that multiple features of host social behavior influence infection risk and suggest that synergism between traits also has important effects on host parasite load.

  6. Food stoichiometry affects the outcome of Daphnia–parasite interaction

    PubMed Central

    Aalto, Sanni L; Pulkkinen, Katja

    2013-01-01

    Phosphorus (P) is an essential nutrient for growth in consumers. P-limitation and parasite infection comprise one of the most common stressor pairs consumers confront in nature. We conducted a life-table study using a Daphnia–microsporidian parasite model, feeding uninfected or infected Daphnia with either P-sufficient or P-limited algae, and assessed the impact of the two stressors on life-history traits of the host. Both infection and P-limitation negatively affected some life-history traits tested. However, under P-limitation, infected animals had higher juvenile growth rate as compared with uninfected animals. All P-limited individuals died before maturation, regardless of infection. The numbers of spore clusters of the microsporidian parasite did not differ in P-limited or P-sufficient hosts. P-limitation, but not infection, decreased body phosphorus content and ingestion rates of Daphnia tested in separate experiments. As parasite spore production did not suffer even under extreme P-limitation, our results suggest that parasite was less limited by P than the host. We discuss possible interpretations concerning the stoichiometrical demands of parasite and suggest that our results are explained by parasite-driven changes in carbon (C) allocation of the hosts. We conclude that the impact of nutrient starvation and parasite infection on consumers depends not only on the stoichiometric demands of host but also those of the parasite. PMID:23762513

  7. Differential escape from parasites by two competing introduced crabs

    USGS Publications Warehouse

    Blakeslee, April M.; Keogh, Carolyn L.; Byers, James E.; Kuris, Armand M.; Lafferty, Kevin D.; Torchin, Mark E.

    2009-01-01

    Although introduced species often interact with one another in their novel communities, the role of parasites in these interactions remains less clear. We examined parasite richness and prevalence in 2 shorecrab species with different invasion histories and residency times in an introduced region where their distributions overlap broadly. On the northeastern coast of the USA, the Asian shorecrab Hemigrapsus sanguineus was discovered 20 yr ago, while the European green crab Carcinus maenas has been established for over 200 yr. We used literature and field surveys to evaluate parasitism in both crabs in their native and introduced ranges. We found only 1 parasite species infecting H. sanguineus on the US East Coast compared to 6 species in its native range, while C. maenas was host to 3 parasite species on the East Coast compared to 10 in its native range. The prevalence of parasite infection was also lower for both crabs in the introduced range compared to their native ranges; however, the difference was almost twice as much for H. sanguineus as for C. maenas. There are several explanations that could contribute to C. maenas' greater parasite diversity than that of H. sanguineus on the US East Coast, including differences in susceptibility, time since introduction, manner of introduction (vector), distance from native range, taxonomic isolation, and the potential for parasite identification bias. Our study underscores not just that non-native species lose parasites upon introduction, but that they may do so differentially, with ramifications for their direct interactions and with potential community-level influences.

  8. Myco-Heterophytes and Parasitic Plants in Food Chains.

    ERIC Educational Resources Information Center

    Hershey, David R.

    1999-01-01

    Advocates including plants at several trophic levels when studying food chains. Presents background information on parasitic plants, myco-heterophytes (saprophytes), and carnivorous plants. Contains 20 references. (WRM)

  9. The immunological balance between host and parasite in malaria.

    PubMed

    Deroost, Katrien; Pham, Thao-Thy; Opdenakker, Ghislain; Van den Steen, Philippe E

    2016-03-01

    Coevolution of humans and malaria parasites has generated an intricate balance between the immune system of the host and virulence factors of the parasite, equilibrating maximal parasite transmission with limited host damage. Focusing on the blood stage of the disease, we discuss how the balance between anti-parasite immunity versus immunomodulatory and evasion mechanisms of the parasite may result in parasite clearance or chronic infection without major symptoms, whereas imbalances characterized by excessive parasite growth, exaggerated immune reactions or a combination of both cause severe pathology and death, which is detrimental for both parasite and host. A thorough understanding of the immunological balance of malaria and its relation to other physiological balances in the body is of crucial importance for developing effective interventions to reduce malaria-related morbidity and to diminish fatal outcomes due to severe complications. Therefore, we discuss in this review the detailed mechanisms of anti-malarial immunity, parasite virulence factors including immune evasion mechanisms and pathogenesis. Furthermore, we propose a comprehensive classification of malaria complications according to the different types of imbalances.

  10. Parasites grow larger in faster growing fish hosts.

    PubMed

    Barber, Iain

    2005-02-01

    Parasites depend on host-derived energy for growth and development, and so are potentially affected by the host's ability to acquire nutrients under competitive foraging scenarios. Although parasites might be expected to grow faster in hosts that are better at acquiring nutrients from natural ecosystems, it is also possible that the most competitive hosts are better at countering infections, if they have an improved immune response or are able to limit the availability of nutrients to parasites. I first quantified the ability of uninfected three-spined sticklebacks Gasterosteus aculeatus to compete in groups for sequentially-presented food items, and then exposed either the best or worst competitors to infective stages of the cestode Schistocephalus solidus. Fish were subsequently raised in their original groups, under competitive feeding regimes, for 96 days, after which fish and parasite growth was determined. Unexpectedly, pre-exposure host competitive ability had no effect on susceptibility to infection, or on post-infection growth rate. Furthermore, despite a 120-fold variation in parasite mass at the end of the study, pre-infection competitive ability was not related to parasite growth. The closest predictor of parasite mass was body size-corrected host growth rate, indicating that the fastest growing fish developed the largest parasites. Faster growing hosts therefore apparently provide ideal environments for growing parasites. This finding has important implications for ecology and aquaculture.

  11. Selection by parasites may increase host recombination frequency.

    PubMed

    Fischer, O; Schmid-Hempel, P

    2005-06-22

    Meiotic recombination destroys successful genotypes and it is therefore thought to evolve only under a very limited set of conditions. Here, we experimentally show that recombination rates across two linkage groups of the host, the red flour beetle Tribolium castaneum, increase with exposure to the microsporidian parasite, Nosema whitei, particularly when parasites were allowed to coevolve with their hosts. Selection by randomly varied parasites resulted in smaller effects, while directional selection for insecticide resistance initially reduced recombination slightly. These results, at least tentatively, suggest that short-term benefits of recombination--and thus the evolution of sex--may be related to parasitism.

  12. Parasites and genetic diversity in an invasive bumblebee

    PubMed Central

    Jones, Catherine M; Brown, Mark J F; Ings, Thomas

    2014-01-01

    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. PMID:24749545

  13. Host plant resistance to parasitic weeds; recent progress and bottlenecks.

    PubMed

    Yoder, John I; Scholes, Julie D

    2010-08-01

    Parasitic witchweeds (Striga spp.) and broomrapes (Orobanche and Phelipanche spp.) directly invade the roots of crop plants connecting to the vascular system and abstracting nutrients and water. As a consequence they cause devastating losses in crop yield. Genetic resistance to parasitic weeds is a highly desirable component of any control strategy. Resistance to parasitic plants can occur at different stages of the parasite lifecycle: before attachment to the host, during penetration of the root or after establishment of vascular connections. New studies are beginning to shed light on the molecular mechanisms and signaling pathways involved in plant-plant resistance. The first resistance gene to Striga, encoding a CC-NBS-LRR Resistance protein (R) has been identified and cloned suggesting that host plants resist attack from parasitic plants using similar surveillance mechanisms as those used against fungal and bacterial pathogens. It is becoming clear that the salicylic acid (SA) signaling pathway plays an important role in resistance to parasitic plants and genes encoding pathogenesis-related (PR) proteins are upregulated in a number of the resistant interactions. New strategies for engineering resistance to parasitic plants are also being explored, including the expression of parasite-specific toxins in host roots and RNAi to silence parasite genes crucial for development.

  14. Exposure to parasites increases promiscuity in a freshwater snail

    PubMed Central

    Soper, D. M.; King, K. C.; Vergara, D.; Lively, C. M.

    2014-01-01

    Under the Red Queen hypothesis, outcrossing can produce genetically variable progeny, which may be more resistant, on average, to locally adapted parasites. Mating with multiple partners may enhance this resistance by further increasing the genetic variation among offspring. We exposed Potamopyrgus antipodarum to the eggs of a sterilizing, trematode parasite and tested whether this altered mating behaviour. We found that exposure to parasites increased the number of snail mating pairs and the total number of different mating partners for both males and females. Thus, our results suggest that, in host populations under parasite-mediated selection, exposure to infective propagules increases the rate of mating and the number of mates. PMID:24759366

  15. Host partitioning by parasites in an intertidal crustacean community.

    PubMed

    Koehler, Anson V; Poulin, Robert

    2010-10-01

    Patterns of host use by parasites throughout a guild community of intermediate hosts can depend on several biological and ecological factors, including physiology, morphology, immunology, and behavior. We looked at parasite transmission in the intertidal crustacean community of Lower Portobello Bay, Dunedin, New Zealand, with the intent of: (1) mapping the flow of parasites throughout the major crustacean species, (2) identifying hosts that play the most important transmission role for each parasite, and (3) assessing the impact of parasitism on host populations. The most prevalent parasites found in 14 species of crustaceans (635 specimens) examined were the trematodes Maritrema novaezealandensis and Microphallus sp., the acanthocephalans Profilicollis spp., the nematode Ascarophis sp., and an acuariid nematode. Decapods were compatible hosts for M. novaezealandensis, while other crustaceans demonstrated lower host suitability as shown by high levels of melanized and immature parasite stages. Carapace thickness, gill morphology, and breathing style may contribute to the differential infection success of M. novaezealandensis and Microphallus sp. in the decapod species. Parasite-induced host mortality appears likely with M. novaezealandensis in the crabs Austrohelice crassa, Halicarcinus varius, Hemigrapsus sexdentatus, and Macrophthalmus hirtipes, and also with Microphallus sp. in A. crassa. Overall, the different parasite species make different use of available crustacean intermediate hosts and possibly contribute to intertidal community structure.

  16. Childhood parasitic infections endemic to the United States.

    PubMed

    Barry, Meagan A; Weatherhead, Jill E; Hotez, Peter J; Woc-Colburn, Laila

    2013-04-01

    Endemic parasitic infections in the United States are more frequent than is commonly perceived. Intestinal parasitic infection with Cryptosporidium, Dientamoeba, and Giardia occurs most often in children in northern states during the summer months. Zoonotic Toxocara and Toxoplasma parasitic infections are more frequent in southern states, in African Americans, and in populations with lower socioeconomic status. Approximately 300, 000 people in the United States have Trypanosoma cruzi infection. Local, vector-borne transmission of T cruzi and Leishmania infections has been documented in southern states. Parasitic diseases endemic to the United States are not uncommon but are understudied.

  17. Speciation in Thaparocleidus (Monogenea: Dactylogyridae) Parasitizing Asian Pangasiid Catfishes

    PubMed Central

    Šimková, Andrea; Serbielle, Celine; Vanhove, Maarten P. M.; Morand, Serge

    2013-01-01

    The phylogeny of monogeneans of the genus Thaparocleidus that parasitize the gills of Pangasiidae in Borneo and Sumatra was inferred from molecular data to investigate parasite speciation. The phylogeny of the Pangasiidae was also reconstructed in order to investigate host-parasite coevolutionary history. The monophyly of Thaparocleidus parasitizing Pangasiidae was confirmed. Low intraspecies molecular variability was observed in three Thaparocleidus species collected from geographically distant localities. However, a high intraspecies molecular variability was observed in two Thaparocleidus species suggesting that these species represent a complex of species highly similar in morphology. Distance-based and tree-based methods revealed a significant global fit between parasite and host phylogenies. Parasite duplication (i.e., intrahost speciation) was recognized as the most common event in Thaparocleidus, while the numbers of cospeciation and host switches were lower and similar to each other. When collapsing nodes correspond to duplication cases, our results suggest host switches in the Thaparocleidus-Pangasiidae system precluding congruence between host and parasite trees. We found that the morphometric variability of the parasite attachment organ is not linked to phylogeny, suggesting that the attachment organ is under adaptive constraint. We showed that haptor morphometry is linked to host specificity, whereby nonspecific parasites display higher morphometric variability than specialists. PMID:24350263

  18. Alternative parasite development in transmission strategies: how time flies!

    PubMed

    Badets, M; Morrison, C; Verneau, O

    2010-10-01

    Among parasitic platyhelminths with complex life cycles, it has been well documented that transmission opportunities are the main forces shaping the diversity of life-history traits and parasite developmental strategies. While deviations in the development pathway usually involve shortening of life cycles, their extension may also occur following perception of remaining time by parasites. Polystoma gallieni, the monogenean parasite of Hyla meridionalis, is able to trigger two alternative developmental strategies depending on the physiological stage of the tadpoles upon which larvae attach. The distribution and reproductive outputs of both resulting phenotypes were surveyed to address questions about the dynamics of transmission in natural environments. Because modifications in the completion of life cycles can have drawbacks which may perturb the dynamic equilibrium of the resulting host-parasite systems, experimental infestations were also performed to assess parasite-parasite interactions. Our results suggest that the bladder adult phenotype, which involves transmission between frogs and tadpoles, is supplied secondarily by the branchial phenotype which involves transmission between tadpoles and metamorphs. They also support the occurrence of finely tuned trade-offs between hosts and parasites and highlight positive trends behind the extension of direct life cycles, in which host-derived signals account for the remaining time to achieve parasitic transmission.

  19. Phylogenetically related and ecologically similar carnivores harbour similar parasite assemblages.

    PubMed

    Huang, Shan; Bininda-Emonds, Olaf R P; Stephens, Patrick R; Gittleman, John L; Altizer, Sonia

    2014-05-01

    Most parasites infect multiple hosts, but what factors determine the range of hosts a given parasite can infect? Understanding the broad scale determinants of parasite distributions across host lineages is important for predicting pathogen emergence in new hosts and for estimating pathogen diversity in understudied host species. In this study, we used a new data set on 793 parasite species reported from free-ranging populations of 64 carnivore species to examine the factors that influence parasite sharing between host species. Our results showed that parasites are more commonly shared between phylogenetically related host species pairs. Additionally, host species with higher similarity in biological traits and greater geographic range overlap were also more likely to share parasite species. Of three measures of phylogenetic relatedness considered here, the number divergence events that separated host species pairs most strongly influenced the likelihood of parasite sharing. We also showed that viruses and helminths tend to infect carnivore hosts within more restricted phylogenetic ranges than expected by chance. Overall, our results underscore the importance of host evolutionary history in determining parasite host range, even when simultaneously considering other factors such as host ecology and geographic distribution.

  20. Generation of Transgenic Rodent Malaria Parasites Expressing Human Malaria Parasite Proteins.

    PubMed

    Salman, Ahmed M; Mogollon, Catherin Marin; Lin, Jing-Wen; van Pul, Fiona J A; Janse, Chris J; Khan, Shahid M

    2015-01-01

    We describe methods for the rapid generation of transgenic rodent Plasmodium berghei (Pb) parasites that express human malaria parasite (HMP) proteins, using the recently developed GIMO-based transfection methodology. Three different genetic modifications are described resulting in three types of transgenic parasites. (1) Additional Gene (AG) mutants. In these mutants the HMP gene is introduced as an "additional gene" into a silent/neutral locus of the Pb genome under the control of either a constitutive or stage-specific Pb promoter. This method uses the GIMO-transfection protocol and AG mutants are generated by replacing the positive-negative selection marker (SM) hdhfr::yfcu cassette in a neutral locus of a standard GIMO mother line with the HMP gene expression cassette, resulting in SM free transgenic parasites. (2) Double-step Replacement (DsR) mutants. In these mutants the coding sequence (CDS) of the Pb gene is replaced with the CDS of the HMP ortholog in a two-step GIMO-transfection procedure. This process involves first the replacement of the Pb CDS with the hdhfr::yfcu SM, followed by insertion of the HMP ortholog at the same locus thereby replacing hdhfr::yfcu with the HMP CDS. These steps use the GIMO-transfection protocol, which exploits both positive selection for Pb orthologous gene-deletion and negative selection for HMP gene-insertion, resulting in SM free transgenic parasites. (3) Double-step Insertion (DsI) mutants. When a Pb gene is essential for blood stage development the DsR strategy is not possible. In these mutants the HMP expression cassette is first introduced into the neutral locus in a standard GIMO mother line as described for AG mutants but under the control elements of the Pb orthologous gene; subsequently, the Pb ortholog CDS is targeted for deletion through replacement of the Pb CDS with the hdhfr::yfcu SM, resulting in transgenic parasites with a new GIMO locus permissive for additional gene-insertion modifications.The different

  1. Parasites and parasite management practices of organic and conventional dairy herds in Minnesota.

    PubMed

    Sorge, U S; Moon, R D; Stromberg, B E; Schroth, S L; Michels, L; Wolff, L J; Kelton, D F; Heins, B J

    2015-05-01

    The objective of this study was to describe the prevalence and practices used to manage internal helminth parasites and external arthropod parasites on organic and conventional dairy herds in Minnesota. All organic (ORG) dairy herds in Minnesota (n=114) and a convenience sample of conventional herds were invited to participate in the study. Thirty-five ORG herds and 28 conventional herds were visited once in summer and fall of 2012. Conventional dairy herds were split into small conventional (SC,<200 cows) and medium-sized conventional herds (MC, ≥200 cows) so that SC herds were comparable in size to the ORG herds. Dairy managers were surveyed to assess their farm management practices and perceptions about parasites, hygiene scores were recorded for adult stock, and fecal samples were collected from a nominal 20 breeding-age heifers to characterize abundance of internal parasites. Nonparametric tests were used to compare fecal egg counts per gram (FEC) among farms grouped by management systems and practices. Organic farms had more designated pasture and were more likely to use rotational grazing compared with conventional farms, but the stocking densities of animals on pasture were similar among farm types. The overall FEC were very low, and only a few individual ORG heifers had FEC >500 eggs/gram. Samples from heifers on ORG farms had significantly more strongyle-type eggs than those on SC and MC farms (ORG: 6.6±2.1; SC: 0.5±0.3; MC: 0.8±0.7), but egg counts of other types of gastrointestinal parasites did not differ significantly among the 3 herd groups. Fly control measures were applied mainly to milking cows and preweaned calves and were used on 88.6% of ORG herds, 60.0% of SC herds, and 91.7% of MC herds. Approximately half of the producers reported having seen skin conditions suggestive of lice or tail mange in their cattle during the previous winter (ORG: 48.6%, SC: 57.1%, MC: 53.9%). Although most conventional producers reported treating these skin

  2. The helminth parasite proteome at the host-parasite interface - Informing diagnosis and control.

    PubMed

    van der Ree, Anna M; Mutapi, Francisca

    2015-10-01

    Helminth parasites are a significant health burden for humans in the developing world and also cause substantial economic losses in livestock production across the world. The combined lack of vaccines for the major human and veterinary helminth parasites in addition to the development of drug resistance to anthelmintics in sheep and cattle mean that controlling helminth infection and pathology remains a challenge. However, recent high throughput technological advances mean that screening for potential drug and vaccine candidates is now easier than in previous decades. A better understanding of the host-parasite interactions occurring during infection and pathology and identifying pathways that can be therapeutically targeted for more effective and 'evolution proof' interventions is now required. This review highlights some of the advances that have been made in understanding the host-parasite interface in helminth infections using studies of the temporal expression of parasite proteins, i.e. the parasite proteome, and discuss areas for potential future research and translation.

  3. Host responses to interspecific brood parasitism: a by-product of adaptations to conspecific parasitism?

    PubMed Central

    2014-01-01

    Background Why have birds evolved the ability to reject eggs? Typically, foreign egg discrimination is interpreted as evidence that interspecific brood parasitism (IP) has selected for the host’s ability to recognize and eliminate foreign eggs. Fewer studies explore the alternative hypothesis that rejection of interspecific eggs is a by-product of host defenses, evolved against conspecific parasitism (CP). We performed a large scale study with replication across taxa (two congeneric Turdus thrushes), space (populations), time (breeding seasons), and treatments (three types of experimental eggs), using a consistent design of egg rejection experiments (n = 1057 nests; including controls), in areas with potential IP either present (Europe; native populations) or absent (New Zealand; introduced populations). These comparisons benefited from the known length of allopatry (one and a half centuries), with no gene flow between native and introduced populations, which is rarely available in host-parasite systems. Results Hosts rejected CP at unusually high rates for passerines (up to 60%). CP rejection rates were higher in populations with higher conspecific breeding densities and no risks of IP, supporting the CP hypothesis. IP rejection rates did not covary geographically with IP risk, contradicting the IP hypothesis. High egg rejection rates were maintained in the relatively long-term isolation from IP despite non-trivial rejection costs and errors. Conclusions These egg rejection patterns, combined with recent findings that these thrushes are currently unsuitable hosts of the obligate parasitic common cuckoo (Cuculus canorus), are in agreement with the hypothesis that the rejection of IP is a by-product of fine-tuned egg discrimination evolved due to CP. Our study highlights the importance of considering both IP and CP simultaneously as potential drivers in the evolution of egg discrimination, and illustrates how populations introduced to novel ecological contexts

  4. Motility modes of the parasite Trypanosoma brucei

    NASA Astrophysics Data System (ADS)

    Temel, Fatma Zeynep; Qu, Zijie; McAllaster, Michael; de Graffenried, Christopher; Breuer, Kenneth

    2015-11-01

    The parasitic single-celled protozoan Trypanosoma brucei causes African Sleeping Sickness, which is a fatal disease in humans and animals that threatens more than 60 million people in 36 African countries. Cell motility plays a critical role in the developmental phases and dissemination of the parasite. Unlike many other motile cells such as bacteria Escherichia coli or Caulobacter crescentus, the flagellum of T. brucei is attached along the length of its awl-like body, producing a unique mode of motility that is not fully understood or characterized. Here, we report on the motility of T. brucei, which swims using its single flagellum employing both rotating and undulating propulsion modes. We tracked cells in real-time in three dimensions using fluorescent microscopy. Data obtained from experiments using both short-term tracking within the field of view and long-term tracking using a tracking microscope were analyzed. Motility modes and swimming speed were analyzed as functions of cell size, rotation rate and undulation pattern. Research supported by NSF.

  5. The distinct proteome of placental malaria parasites.

    SciTech Connect

    Fried, Michal; Hixson, Kim K.; Anderson, Lori; Ogata, Yuko; Mutabingwa, Theonest K.; Duffy, Patrick E.

    2007-09-01

    Malaria proteins expressed on the surface of Plasmodium falciparum infected erythrocytes (IE) mediate adhesion and are targeted by protective immune responses. During pregnancy, IE sequester in the placenta. Placental IE bind to the molecule chondroitin sulfate A (CSA) and preferentially transcribe the gene that encodes VAR2CSA, a member of the PfEMP1 variant surface antigen family. Over successive pregnancies women develop specific immunity to CSA-binding IE and antibodies to VAR2CSA. We used tandem mass spectrometry together with accurate mass and time tag technology to study IE membrane fractions of placental parasites. VAR2CSA peptides were detected in placental IE and in IE from children, but the MC variant of VAR2CSA was specifically associated with placental IE. We identified six conserved hypothetical proteins with putative TM or signal peptides that were exclusively expressed by the placental IE, and 11 such proteins that were significantly more abundant in placental IE. One of these hypothetical proteins, PFI1785w, is a 42kDa molecule detected by Western blot in parasites infecting pregnant women but not those infecting children.

  6. Inflammasomes in host response to protozoan parasites.

    PubMed

    Zamboni, Dario S; Lima-Junior, Djalma S

    2015-05-01

    Inflammasomes are multimeric complexes of proteins that are assembled in the host cell cytoplasm in response to specific stress signals or contamination of the cytoplasm by microbial molecules. The canonical inflammasomes are composed of at least three main components: an inflammatory caspase (caspase-1, caspase-11), an adapter molecule (such as ASC), and a sensor protein (such as NLRP1, NLRP3, NLRP12, NAIP1, NAIP2, NAIP5, or AIM2). The sensor molecule determines the inflammasome specificity by detecting specific microbial products or cell stress signals. Upon activation, these molecular platforms facilitate restriction of microbial replication and trigger an inflammatory form of cell death called pyroptosis, thus accounting for the genesis of inflammatory processes. Inflammasome activation has been widely reported in response to pathogenic bacteria. However, recent reports have highlighted the important role of the inflammasomes in the host response to the pathogenesis of infections caused by intracellular protozoan parasites. Herein, we review the activation and specific roles of inflammasomes in recognition and host responses to intracellular protozoan parasites such as Trypanosoma cruzi, Toxoplasma gondii, Plasmodium spp., and Leishmania spp.

  7. Ancient Human Parasites in Ethnic Chinese Populations

    PubMed Central

    Yeh, Hui-Yuan; Mitchell, Piers D.

    2016-01-01

    Whilst archaeological evidence for many aspects of life in ancient China is well studied, there has been much less interest in ancient infectious diseases, such as intestinal parasites in past Chinese populations. Here, we bring together evidence from mummies, ancient latrines, and pelvic soil from burials, dating from the Neolithic Period to the Qing Dynasty, in order to better understand the health of the past inhabitants of China and the diseases endemic in the region. Seven species of intestinal parasite have been identified, namely roundworm, whipworm, Chinese liver fluke, oriental schistosome, pinworm, Taenia sp. tapeworm, and the intestinal fluke Fasciolopsis buski. It was found that in the past, roundworm, whipworm, and Chinese liver fluke appear to have been much more common than the other species. While roundworm and whipworm remained common into the late 20th century, Chinese liver fluke seems to have undergone a marked decline in its prevalence over time. The iconic transport route known as the Silk Road has been shown to have acted as a vector for the transmission of ancient diseases, highlighted by the discovery of Chinese liver fluke in a 2,000 year-old relay station in northwest China, 1,500 km outside its endemic range. PMID:27853113

  8. Recent advances in understanding apicomplexan parasites

    PubMed Central

    Seeber, Frank; Steinfelder, Svenja

    2016-01-01

    Intracellular single-celled parasites belonging to the large phylum Apicomplexa are amongst the most prevalent and morbidity-causing pathogens worldwide. In this review, we highlight a few of the many recent advances in the field that helped to clarify some important aspects of their fascinating biology and interaction with their hosts. Plasmodium falciparum causes malaria, and thus the recent emergence of resistance against the currently used drug combinations based on artemisinin has been of major interest for the scientific community. It resulted in great advances in understanding the resistance mechanisms that can hopefully be translated into altered future drug regimens. Apicomplexa are also experts in host cell manipulation and immune evasion. Toxoplasma gondii and Theileria sp., besides Plasmodium sp., are species that secrete effector molecules into the host cell to reach this aim. The underlying molecular mechanisms for how these proteins are trafficked to the host cytosol ( T. gondii and Plasmodium) and how a secreted protein can immortalize the host cell ( Theileria sp.) have been illuminated recently. Moreover, how such secreted proteins affect the host innate immune responses against T. gondii and the liver stages of Plasmodium has also been unraveled at the genetic and molecular level, leading to unexpected insights. Methodological advances in metabolomics and molecular biology have been instrumental to solving some fundamental puzzles of mitochondrial carbon metabolism in Apicomplexa. Also, for the first time, the generation of stably transfected Cryptosporidium parasites was achieved, which opens up a wide variety of experimental possibilities for this understudied, important apicomplexan pathogen. PMID:27347391

  9. Phylogeny, host-parasite relationship and zoogeography

    PubMed Central

    1999-01-01

    Phylogeny is the evolutionary history of a group or the lineage of organisms and is reconstructed based on morphological, molecular and other characteristics. The genealogical relationship of a group of taxa is often expressed as a phylogenetic tree. The difficulty in categorizing the phylogeny is mainly due to the existence of frequent homoplasies that deceive observers. At the present time, cladistic analysis is believed to be one of the most effective methods of reconstructing a phylogenetic tree. Excellent computer program software for phylogenetic analysis is available. As an example, cladistic analysis was applied for nematode genera of the family Acuariidae, and the phylogenetic tree formed was compared with the system used currently. Nematodes in the genera Nippostrongylus and Heligmonoides were also analyzed, and the validity of the reconstructed phylogenetic trees was observed from a zoogeographical point of view. Some of the theories of parasite evolution were briefly reviewed as well. Coevolution of parasites and humans was discussed with special reference to the evolutionary relationship between Enterobius and primates. PMID:10634036

  10. Topoisomerase II from Human Malaria Parasites

    PubMed Central

    Mudeppa, Devaraja G.; Kumar, Shiva; Kokkonda, Sreekanth; White, John; Rathod, Pradipsinh K.

    2015-01-01

    Historically, type II topoisomerases have yielded clinically useful drugs for the treatment of bacterial infections and cancer, but the corresponding enzymes from malaria parasites remain understudied. This is due to the general challenges of producing malaria proteins in functional forms in heterologous expression systems. Here, we express full-length Plasmodium falciparum topoisomerase II (PfTopoII) in a wheat germ cell-free transcription-translation system. Functional activity of soluble PfTopoII from the translation lysates was confirmed through both a plasmid relaxation and a DNA decatenation activity that was dependent on magnesium and ATP. To facilitate future drug discovery, a convenient and sensitive fluorescence assay was established to follow DNA decatenation, and a stable, truncated PfTopoII was engineered for high level enzyme production. PfTopoII was purified using a DNA affinity column. Existing TopoII inhibitors previously developed for other non-malaria indications inhibited PfTopoII, as well as malaria parasites in culture at submicromolar concentrations. Even before optimization, inhibitors of bacterial gyrase, GSK299423, ciprofloxacin, and etoposide exhibited 15-, 57-, and 3-fold selectivity for the malarial enzyme over human TopoII. Finally, it was possible to use the purified PfTopoII to dissect the different modes by which these varying classes of TopoII inhibitors could trap partially processed DNA. The present biochemical advancements will allow high throughput chemical screening of compound libraries and lead optimization to develop new lines of antimalarials. PMID:26055707

  11. Parasite prevalence corresponds to host life history in a diverse assemblage of afrotropical birds and haemosporidian parasites.

    PubMed

    Lutz, Holly L; Hochachka, Wesley M; Engel, Joshua I; Bell, Jeffrey A; Tkach, Vasyl V; Bates, John M; Hackett, Shannon J; Weckstein, Jason D

    2015-01-01

    Avian host life history traits have been hypothesized to predict rates of infection by haemosporidian parasites. Using molecular techniques, we tested this hypothesis for parasites from three haemosporidian genera (Plasmodium, Haemoproteus, and Leucocytozoon) collected from a diverse sampling of birds in northern Malawi. We found that host life history traits were significantly associated with parasitism rates by all three parasite genera. Nest type and nest location predicted infection probability for all three parasite genera, whereas flocking behavior is an important predictor of Plasmodium and Haemoproteus infection and habitat is an important predictor of Leucocytozoon infection. Parasite prevalence was 79.1% across all individuals sampled, higher than that reported for comparable studies from any other region of the world. Parasite diversity was also exceptionally high, with 248 parasite cytochrome b lineages identified from 152 host species. A large proportion of Plasmodium, Haemoproteus, and Leucocytozoon parasite DNA sequences identified in this study represent new, previously undocumented lineages (n = 201; 81% of total identified) based on BLAST queries against the avian malaria database, MalAvi.

  12. ADULT TERTIAN MALARIAL PARASITES ATTACHED TO PERIPHERAL CORPUSCULAR MOUNDS. THE EXTRACELLULAR RELATION OF THE PARASITES TO THE RED CORPUSCLES.

    PubMed

    Lawson, M R

    1915-06-01

    1. The malarial parasite is extracellular throughout its entire life cycle; that is, when it is not free in the blood serum, it is attached to the external surface of the red corpuscle. 2. Adult parasites follow the same procedure in attaching themselves to the outer surface of the red corpuscles as do the young parasites. 3. Adult parasites are most frequently seen attached to surface corpuscular mounds. 4. Corpuscular mounds projecting at the periphery of the red corpuscles and encircled by the pseudopodia of adult parasites, are proof positive of the extracellular relation of the adult parasite to the red corpuscle. 5. Adult parasites attached to peripheral corpuscular mounds are only found in appreciable numbers when the red corpuscles are not badly damaged, so that the mounds show more or less hemoglobin content. 6. The nuclei or protoplasm of adult parasites extending beyond the periphery of the red corpuscles is additional evidence of the extracellular relation of the parasites to the red corpuscle.

  13. Host-parasite relationships as determinants of heavy metal concentrations in perch (Perca fluviatilis) and its intestinal parasite infection.

    PubMed

    Brázová, Tímea; Hanzelová, Vladimíra; Miklisová, Dana; Šalamún, Peter; Vidal-Martínez, Víctor M

    2015-12-01

    The concentrations of As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, and Zn and their bioconcentration factors (BCFs) were determined in two intestinal parasites, an acanthocephalan, Acanthocephalus lucii, a tapeworm, Proteocephalus percae, present in the same host, the European perch (Perca fluviatilis, L.), in the heavily polluted Ružín reservoir in eastern Slovakia. The bioaccumulation of heavy metals in the fish organs and parasites was studied for acanthocephalan and tapeworm monoinfections or mixed infections by the two parasites and for the size of their parasitic infrapopulations. Bioconcentration factors (c[parasite]/c[muscle tissue]) showed that the concentrations of As, Ni, Pb and Zn were higher in mixed infections than in monoinfections. Negative correlations between heavy metal concentrations in perch organs and the parasites were found. For example, higher concentrations of Ni and Zn in both parasite species corresponded with lower metal concentrations in perch and hard roe. Likewise, significant negative relationships between metal concentrations in fish organs and number of parasites were noticed with lower levels of Pb in fish harbouring higher numbers of tapeworms. Similarly, in both parasite species the concentrations of some essential elements (Cr, Mn) were lower at high infection intensities compared to low intensities. Our study revealed that the differential concentration of heavy metals in perch organs was affected by the type of infection (mono- or mixed-infection), and needs to be considered in field ecotoxicological and parasitological studies as a potentially important factor influencing the pollutant concentrations in fish.

  14. Parasite Prevalence Corresponds to Host Life History in a Diverse Assemblage of Afrotropical Birds and Haemosporidian Parasites

    PubMed Central

    Lutz, Holly L.; Hochachka, Wesley M.; Engel, Joshua I.; Bell, Jeffrey A.; Tkach, Vasyl V.; Bates, John M.; Hackett, Shannon J.; Weckstein, Jason D.

    2015-01-01

    Avian host life history traits have been hypothesized to predict rates of infection by haemosporidian parasites. Using molecular techniques, we tested this hypothesis for parasites from three haemosporidian genera (Plasmodium, Haemoproteus, and Leucocytozoon) collected from a diverse sampling of birds in northern Malawi. We found that host life history traits were significantly associated with parasitism rates by all three parasite genera. Nest type and nest location predicted infection probability for all three parasite genera, whereas flocking behavior is an important predictor of Plasmodium and Haemoproteus infection and habitat is an important predictor of Leucocytozoon infection. Parasite prevalence was 79.1% across all individuals sampled, higher than that reported for comparable studies from any other region of the world. Parasite diversity was also exceptionally high, with 248 parasite cytochrome b lineages identified from 152 host species. A large proportion of Plasmodium, Haemoproteus, and Leucocytozoon parasite DNA sequences identified in this study represent new, previously undocumented lineages (n = 201; 81% of total identified) based on BLAST queries against the avian malaria database, MalAvi. PMID:25853491

  15. Sequence mining and transcript profiling to explore cyst nematode parasitism

    PubMed Central

    Elling, Axel A; Mitreva, Makedonka; Gai, Xiaowu; Martin, John; Recknor, Justin; Davis, Eric L; Hussey, Richard S; Nettleton, Dan; McCarter, James P; Baum, Thomas J

    2009-01-01

    Background Cyst nematodes are devastating plant parasites that become sedentary within plant roots and induce the transformation of normal plant cells into elaborate feeding cells with the help of secreted effectors, the parasitism proteins. These proteins are the translation products of parasitism genes and are secreted molecular tools that allow cyst nematodes to infect plants. Results We present here the expression patterns of all previously described parasitism genes of the soybean cyst nematode, Heterodera glycines, in all major life stages except the adult male. These insights were gained by analyzing our gene expression dataset from experiments using the Affymetrix Soybean Genome Array GeneChip, which contains probeset sequences for 6,860 genes derived from preparasitic and parasitic H. glycines life stages. Targeting the identification of additional H. glycines parasitism-associated genes, we isolated 633 genes encoding secretory proteins using algorithms to predict secretory signal peptides. Furthermore, because some of the known H. glycines parasitism proteins have strongest similarity to proteins of plants and microbes, we searched for predicted protein sequences that showed their highest similarities to plant or microbial proteins and identified 156 H. glycines genes, some of which also contained a signal peptide. Analyses of the expression profiles of these genes allowed the formulation of hypotheses about potential roles in parasitism. This is the first study combining sequence analyses of a substantial EST dataset with microarray expression data of all major life stages (except adult males) for the identification and characterization of putative parasitism-associated proteins in any parasitic nematode. Conclusion We have established an expression atlas for all known H. glycines parasitism genes. Furthermore, in an effort to identify additional H. glycines genes with putative functions in parasitism, we have reduced the currently known 6,860 H

  16. Parasite Rates of Discovery, Global Species Richness and Host Specificity.

    PubMed

    Costello, Mark John

    2016-10-01

    If every metazoan species has at least one host-specific parasite, as several local scale studies have suggested, then half of all species could be parasites. However, host specificity varies significantly depending on host phylogeny, body size, habitat, and geographic distribution. The best studied hosts tend to be vertebrates, larger animals, and/or widespread, and thus have a higher number of parasites and host-specific parasites. Thus, host specificity for these well-known taxa cannot be simply extrapolated to other taxa, notably invertebrates, small sized, and more endemic species, which comprise the major portion of yet to be discovered species. At present, parasites of animals comprise about 5% of named species. This article analyzed the rate of description of several largely parasitic taxa within crustaceans (copepods, amphipods, isopods, pentastomids, cirripeds), marine helminths (nematodes, acanthocephalans, flukes), gastropod molluscs, insects (ticks, fleas, biting flies, strepispterans), and microsporidia. The period of highest discovery has been most recent for the marine helminths and microsporids. The number of people describing parasites has been increasing since the 1960s, as it has for all other taxa. However, the number of species being described per decade relative to the number of authors has been decreasing except for the helminths. The results indicate that more than half of all parasites have been described, and two-thirds of host taxa, although the proportion varies between taxa. It is highly unlikely that the number of named species of parasites will ever approach that of their hosts. This contrast between the proportion that parasites comprise of local and global faunas suggests that parasites are less host specific and more widespread than local scale studies suggest.

  17. Behavioural resistance against a protozoan parasite in the monarch butterfly.

    PubMed

    Lefèvre, Thierry; Chiang, Allen; Kelavkar, Mangala; Li, Hui; Li, James; de Castillejo, Carlos Lopez Fernandez; Oliver, Lindsay; Potini, Yamini; Hunter, Mark D; de Roode, Jacobus C

    2012-01-01

    1. As parasites can dramatically reduce the fitness of their hosts, there should be strong selection for hosts to evolve and maintain defence mechanisms against their parasites. One way in which hosts may protect themselves against parasitism is through altered behaviours, but such defences have been much less studied than other forms of parasite resistance. 2. We studied whether monarch butterflies (Danaus plexippus L.) use altered behaviours to protect themselves and their offspring against the protozoan parasite Ophryocystis elektroscirrha (McLaughlin & Myers (1970), Journal of Protozoology, 17, p. 300). In particular, we studied whether (i) monarch larvae can avoid contact with infectious parasite spores; (ii) infected larvae preferentially consume therapeutic food plants when given a choice or increase the intake of such plants in the absence of choice; and (iii) infected female butterflies preferentially lay their eggs on medicinal plants that make their offspring less sick. 3. We found that monarch larvae were unable to avoid infectious parasite spores. Larvae were also not able to preferentially feed on therapeutic food plants or increase the ingestion of such plants. However, infected female butterflies preferentially laid their eggs on food plants that reduce parasite growth in their offspring. 4. Our results suggest that animals may use altered behaviours as a protection against parasites and that such behaviours may be limited to a single stage in the host-parasite life cycle. Our results also suggest that animals may use altered behaviours to protect their offspring instead of themselves. Thus, our study indicates that an inclusive fitness approach should be adopted to study behavioural defences against parasites.

  18. Host lifespan and the evolution of resistance to multiple parasites.

    PubMed

    Donnelly, R; White, A; Boots, M

    2017-03-01

    Hosts are typically challenged by multiple parasites, but to date theory on the evolution of resistance has mainly focused on single infections. We develop a series of models that examine the impact of multiple parasites on the evolution of resistance under the assumption that parasites coexist at the host population scale as a consequence of superinfection. In this way, we are able to explicitly examine the impact of ecological dynamics on the evolutionary outcome. We use our models to address a key question of how host lifespan affects investment in resistance to multiple parasites. We show that investment in costly resistance depends on the specificity of the immune response and on whether or not the focal parasite leads to more acute infection than the co-circulating parasite. A key finding is that investment in resistance always increases as the immune response becomes more general independently of whether it is the focal or the co-circulating parasite that exploits the host most aggressively. Long-lived hosts always invest more than short-lived hosts in both general resistance and resistance that is specific to relatively acute focal parasites. However, for specific resistance to parasites that are less acute than co-circulating parasites it is the short-lived hosts that are predicted to invest most. We show that these results apply whatever the mode of defence, that is whether it is through avoidance or through increased recovery, with or without acquired immunity, or through acquired immunity itself. As a whole, our results emphasize the importance of considering multiple parasites in determining optimal immune investment in eco-evolutionary systems.

  19. Infracommunity structure of parasites of Hemigymnus melapterus (Pisces: Labridae) from Lizard Island, Australia: the importance of habitat and parasite body size.