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Sample records for mixed-species plasmodium infections

  1. Detection of Mixed-Species Infections of Plasmodium falciparum and Plasmodium vivax by Nested PCR and Rapid Diagnostic Tests in Southeastern Iran

    PubMed Central

    Ehtesham, Reyhaneh; Fazaeli, Asghar; Raeisi, Ahmad; Keshavarz, Hossein; Heidari, Aliehsan

    2015-01-01

    Coexistence of two species of Plasmodium in a single host has disrupted the diagnosis and treatment of malaria. This study was designed to evaluate the ability of rapid diagnostic test (RDT) kits for the diagnosis of mixed-species malaria infections in southeastern Iran. A total of 100 malaria patients were included in the study out of 164 randomly suspected symptomatic malaria patients from May to November 2012. Nested polymerase chain reaction (PCR) was also used to judge the ability of microscopy versus RDT kits for detecting mixed species. The sensitivity of light microscopy for the detection of mixed-species malaria infections was 16.6% (95% confidence interval [CI] = 3–49.1). Nested PCR revealed 12 patients with mixed-species infection. The CareStart Pv/Pf Combo kit detected 58% of the mixed-species infections, which were determined by nested PCR (sensitivity = 58.3%; 95% CI = 28.5–83.5). For identifying P. falciparum, P. vivax, and mixed-species infections, the concordance rates (kappa statistics) of microscopy and CareStart Pv/Pf Combo kit with nested PCR were 0.76 and 0.79, respectively (P = 0.001). This study underlines the effectiveness of RDT kits to improve the differentiation of mixed-species malaria infections in endemic areas where the prevalence of chloroquine resistance is high. PMID:25962771

  2. Effect of Transmission Setting and Mixed Species Infections on Clinical Measures of Malaria in Malawi

    PubMed Central

    Bruce, Marian C.; Macheso, Allan; Kelly-Hope, Louise A.; Nkhoma, Standwell; McConnachie, Alex; Molyneux, Malcolm E.

    2008-01-01

    Background In malaria endemic regions people are commonly infected with multiple species of malaria parasites but the clinical impact of these Plasmodium co-infections is unclear. Differences in transmission seasonality and transmission intensity between endemic regions have been suggested as important factors in determining the effect of multiple species co-infections. Principal Findings In order to investigate the impact of multiple-species infections on clinical measures of malaria we carried out a cross-sectional community survey in Malawi, in 2002. We collected clinical and parasitological data from 2918 participants aged >6 months, and applied a questionnaire to measure malaria morbidity. We examined the effect of transmission seasonality and intensity on fever, history of fever, haemoglobin concentration ([Hb]) and parasite density, by comparing three regions: perennial transmission (PT), high intensity seasonal transmission (HIST) and low intensity seasonal transmission (LIST). These regions were defined using multi-level modelling of PCR prevalence data and spatial and geo-climatic measures. The three Plasmodium species (P. falciparum, P. malariae and P. ovale) were randomly distributed amongst all children but not adults in the LIST and PT regions. Mean parasite density in children was lower in the HIST compared with the other two regions. Mixed species infections had lower mean parasite density compared with single species infections in the PT region. Fever rates were similar between transmission regions and were unaffected by mixed species infections. A history of fever was associated with single species infections but only in the HIST region. Reduced mean [Hb] and increased anaemia was associated with perennial transmission compared to seasonal transmission. Children with mixed species infections had higher [Hb] in the HIST region. Conclusions Our study suggests that the interaction of Plasmodium co-infecting species can have protective effects against

  3. BLOOD-STAGE DYNAMICS AND CLINICAL IMPLICATIONS OF MIXED PLASMODIUM VIVAX–PLASMODIUM FALCIPARUM INFECTIONS

    PubMed Central

    MASON, DANIEL P.; McKENZIE, F. ELLIS

    2008-01-01

    We present a mathematical model of the blood-stage dynamics of mixed Plasmodium vivax–Plasmodium falciparum malaria infections in humans. The model reproduces features of such infections found in nature and suggests several phenomena that may merit clinical attention, including the potential recrudescence of a long-standing, low-level P. falciparum infection following a P. vivax infection or relapse and the capacity of an existing P. vivax infection to reduce the peak parasitemia of a P. falciparum superinfection. We simulate the administration of anti-malarial drugs, and illustrate some potential complications in treating mixed-species malaria infections. Notably, our model indicates that when a mixed-species infection is misdiagnosed as a single-species P. vivax infection, treatment for P. vivax can lead to a surge in P. falciparum parasitemia. PMID:10497972

  4. Prevalence and distribution of human Plasmodium infection in Pakistan.

    PubMed

    Khattak, Aamer A; Venkatesan, Meera; Nadeem, Muhammad F; Satti, Humayoon S; Yaqoob, Adnan; Strauss, Kathy; Khatoon, Lubna; Malik, Salman A; Plowe, Christopher V

    2013-08-28

    Both Plasmodium vivax and Plasmodium falciparum are prevalent in Pakistan, yet up-to-date data on the epidemiology of malaria in Pakistan are not available. This study was undertaken to determine the current prevalence and distribution of Plasmodium species across the country. A malariometric population survey was conducted in 2011 using blood samples collected from 801 febrile patients of all ages in four provinces and the capital city of Islamabad. Microscopically confirmed Plasmodium-positive blood samples were reconfirmed by polymerase chain reaction (PCR). Confirmed parasite-positive samples were subjected to species-specific PCR capable of detecting four species of human malaria. Of the 707 PCR-positive samples, 128 (18%) were P. falciparum, 536 (76%) were P. vivax, and 43 (6%) were mixed P. falciparum and P. vivax. Ninety-four microscopy-positive samples were PCR-negative, and Plasmodium malariae and Plasmodium ovale were not detected. Prevalence of P. vivax ranged from 2.4% in Punjab Province to 10.8% in Sindh Province and prevalence of P. falciparum ranged from 0.1% in Islamabad to 3.8% in Balochistan. Plasmodium infections in Pakistan are largely attributed to P. vivax but P. falciparum and mixed species infections are also prevalent. In addition, regional variation in the prevalence and species composition of malaria is high.

  5. Prevalence and distribution of human Plasmodium infection in Pakistan

    PubMed Central

    2013-01-01

    Background Both Plasmodium vivax and Plasmodium falciparum are prevalent in Pakistan, yet up-to-date data on the epidemiology of malaria in Pakistan are not available. This study was undertaken to determine the current prevalence and distribution of Plasmodium species across the country. Methods A malariometric population survey was conducted in 2011 using blood samples collected from 801 febrile patients of all ages in four provinces and the capital city of Islamabad. Microscopically confirmed Plasmodium-positive blood samples were reconfirmed by polymerase chain reaction (PCR). Confirmed parasite-positive samples were subjected to species-specific PCR capable of detecting four species of human malaria. Results Of the 707 PCR-positive samples, 128 (18%) were P. falciparum, 536 (76%) were P. vivax, and 43 (6%) were mixed P. falciparum and P. vivax. Ninety-four microscopy-positive samples were PCR-negative, and Plasmodium malariae and Plasmodium ovale were not detected. Prevalence of P. vivax ranged from 2.4% in Punjab Province to 10.8% in Sindh Province and prevalence of P. falciparum ranged from 0.1% in Islamabad to 3.8% in Balochistan. Conclusions Plasmodium infections in Pakistan are largely attributed to P. vivax but P. falciparum and mixed species infections are also prevalent. In addition, regional variation in the prevalence and species composition of malaria is high. PMID:23984968

  6. Tetany with Plasmodium falciparum infection.

    PubMed

    Singh, P S; Singh, Neha

    2012-07-01

    Plasmodium falciparum is a malarial infection with high morbidity and wide spectrum of atypical presentation. Here we report an unusual presentation of malaria as tetany with alteration in calcium,phosphate and magnesium metabolism Hypocalcaemia in malaria can cause prolonged Q-Tc interval which could be arisk factor for quinine cardiotoxicity and sudden death Hence monitoring of serum calcium in severe malarial infection and cautious use of quinine in such patients is very important in management

  7. Plasmodium species mixed infections in two areas of Manhiça District, Mozambique

    PubMed Central

    2005-01-01

    We compared the distribution patterns of individual Plasmodium species and mixed-species infections in two geographically close endemic areas, but showing environmental differences. Comparisons concerned circulating Plasmodium infections in both human and mosquito vector populations in the dry and wet seasons, at a micro-epidemiological level (households). Both areas revealed a very high overall prevalence of infection, all year-round and in all age groups. Plasmodium falciparum was the predominant species, being found in the vast majority of infected individuals regardless of the presence of other species. Plasmodium malariae and Plasmodium ovale occurred almost exclusively in mixed infections. Seasonal variation in P. malariae prevalence was observed in one area but not in the other. A decrease in P. malariae prevalence concurred with a marked increase of P. falciparum prevalence. However this was strongly dependent on age and when analysing infections at the individual level, a different pattern between co-infecting species was unveiled. Regarding transmission patterns, in both areas, P. falciparum gametocytes predominated in single infections regardless of age and P. malariae gametocyte carriage increased when its overall prevalence decreased. PMID:16094461

  8. Helminth Parasites Alter Protection against Plasmodium Infection

    PubMed Central

    Salazar-Castañon, Víctor H.; Legorreta-Herrera, Martha

    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. PMID:25276830

  9. 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.

  10. Human Infections with Plasmodium knowlesi, the Philippines

    PubMed Central

    Espino, Fe; Curameng, Peter; Espina, Ronald; Bell, David; Chiodini, Peter; Nolder, Debbie; Sutherland, Colin; Lee, Kim-Sung; Singh, Balbir

    2008-01-01

    Five human cases of infection with the simian malaria parasite Plasmodium knowlesi from Palawan, the Philippines, were confirmed by nested PCR. This study suggests that this zoonotic infection is found across a relatively wide area in Palawan and documents autochthonous cases in the country. PMID:18439369

  11. Acute renal failure in Plasmodium malariae infection.

    PubMed

    Neri, S; Pulvirenti, D; Patamia, I; Zoccolo, A; Castellino, P

    2008-04-01

    We report an unusual case of transfusion-transmitted malaria which remained undiagnosed for several months in an Italian woman splenectomised and polytransfused for thalassaemia major. The infecting species was Plasmodium malariae, and the patient developed acute renal failure, severe thrombocytopenia, and hepatic failure. Treatment with chlorochine was followed by a slow, but complete recovery of renal function.

  12. Orangutans not infected with Plasmodium vivax or P. cynomolgi, Indonesia.

    PubMed

    Singh, Balbir; Simon Divis, Paul Cliff

    2009-10-01

    After orangutans in Indonesia were reported as infected with Plasmodium cynomolgi and P. vivax, we conducted phylogenetic analyses of small subunit ribosomal RNA gene sequences of Plasmodium spp. We found that these orangutans are not hosts of P. cynomolgi and P. vivax. Analysis of >or=1 genes is needed to identify Plasmodium spp. infecting orangutans.

  13. Filarial Worms Reduce Plasmodium Infectivity in Mosquitoes

    PubMed Central

    Aliota, Matthew T.; Chen, Cheng-Chen; Dagoro, Henry; Fuchs, Jeremy F.; Christensen, Bruce M.

    2011-01-01

    Background Co-occurrence of malaria and filarial worm parasites has been reported, but little is known about the interaction between filarial worm and malaria parasites with the same Anopheles vector. Herein, we present data evaluating the interaction between Wuchereria bancrofti and Anopheles punctulatus in Papua New Guinea (PNG). Our field studies in PNG demonstrated that An. punctulatus utilizes the melanization immune response as a natural mechanism of filarial worm resistance against invading W. bancrofti microfilariae. We then conducted laboratory studies utilizing the mosquitoes Armigeres subalbatus and Aedes aegypti and the parasites Brugia malayi, Brugia pahangi, Dirofilaria immitis, and Plasmodium gallinaceum to evaluate the hypothesis that immune activation and/or development by filarial worms negatively impact Plasmodium development in co-infected mosquitoes. Ar. subalbatus used in this study are natural vectors of P. gallinaceum and B. pahangi and they are naturally refractory to B. malayi (melanization-based refractoriness). Methodology/Principal Findings Mosquitoes were dissected and Plasmodium development was analyzed six days after blood feeding on either P. gallinaceum alone or after taking a bloodmeal containing both P. gallinaceum and B. malayi or a bloodmeal containing both P. gallinaceum and B. pahangi. There was a significant reduction in the prevalence and mean intensity of Plasmodium infections in two species of mosquito that had dual infections as compared to those mosquitoes that were infected with Plasmodium alone, and was independent of whether the mosquito had a melanization immune response to the filarial worm or not. However, there was no reduction in Plasmodium development when filarial worms were present in the bloodmeal (D. immitis) but midgut penetration was absent, suggesting that factors associated with penetration of the midgut by filarial worms likely are responsible for the observed reduction in malaria parasite infections

  14. Human Infections and Detection of Plasmodium knowlesi

    PubMed Central

    Daneshvar, Cyrus

    2013-01-01

    SUMMARY Plasmodium knowlesi is a malaria parasite that is found in nature in long-tailed and pig-tailed macaques. Naturally acquired human infections were thought to be extremely rare until a large focus of human infections was reported in 2004 in Sarawak, Malaysian Borneo. Human infections have since been described throughout Southeast Asia, and P. knowlesi is now recognized as the fifth species of Plasmodium causing malaria in humans. The molecular, entomological, and epidemiological data indicate that human infections with P. knowlesi are not newly emergent and that knowlesi malaria is primarily a zoonosis. Human infections were undiagnosed until molecular detection methods that could distinguish P. knowlesi from the morphologically similar human malaria parasite P. malariae became available. P. knowlesi infections cause a spectrum of disease and are potentially fatal, but if detected early enough, infections in humans are readily treatable. In this review on knowlesi malaria, we describe the early studies on P. knowlesi and focus on the epidemiology, diagnosis, clinical aspects, and treatment of knowlesi malaria. We also discuss the gaps in our knowledge and the challenges that lie ahead in studying the epidemiology and pathogenesis of knowlesi malaria and in the prevention and control of this zoonotic infection. PMID:23554413

  15. Human infections and detection of Plasmodium knowlesi.

    PubMed

    Singh, Balbir; Daneshvar, Cyrus

    2013-04-01

    Plasmodium knowlesi is a malaria parasite that is found in nature in long-tailed and pig-tailed macaques. Naturally acquired human infections were thought to be extremely rare until a large focus of human infections was reported in 2004 in Sarawak, Malaysian Borneo. Human infections have since been described throughout Southeast Asia, and P. knowlesi is now recognized as the fifth species of Plasmodium causing malaria in humans. The molecular, entomological, and epidemiological data indicate that human infections with P. knowlesi are not newly emergent and that knowlesi malaria is primarily a zoonosis. Human infections were undiagnosed until molecular detection methods that could distinguish P. knowlesi from the morphologically similar human malaria parasite P. malariae became available. P. knowlesi infections cause a spectrum of disease and are potentially fatal, but if detected early enough, infections in humans are readily treatable. In this review on knowlesi malaria, we describe the early studies on P. knowlesi and focus on the epidemiology, diagnosis, clinical aspects, and treatment of knowlesi malaria. We also discuss the gaps in our knowledge and the challenges that lie ahead in studying the epidemiology and pathogenesis of knowlesi malaria and in the prevention and control of this zoonotic infection.

  16. Engineered Anopheles Immunity to Plasmodium Infection

    PubMed Central

    Cirimotich, Chris; Souza-Neto, Jayme A.; McLean, Kyle J.; Dimopoulos, George

    2011-01-01

    A causative agent of human malaria, Plasmodium falciparum, is transmitted by Anopheles mosquitoes. The malaria parasite is under intensive attack from the mosquito's innate immune system during its sporogonic development. We have used genetic engineering to create immune-enhanced Anopheles stephensi mosquitoes through blood meal-inducible expression of a transgene encoding the IMD pathway-controlled NF-kB Rel2 transcription factor in the midgut and fat-body tissue. Transgenic mosquitoes showed greater resistance to Plasmodium and microbial infection as a result of timely concerted tissue-specific immune attacks involving multiple effectors. The relatively weak impact of this genetic modification on mosquito fitness under laboratory conditions encourages further investigation of this approach for malaria control. PMID:22216006

  17. Engineered anopheles immunity to Plasmodium infection.

    PubMed

    Dong, Yuemei; Das, Suchismita; Cirimotich, Chris; Souza-Neto, Jayme A; McLean, Kyle J; Dimopoulos, George

    2011-12-01

    A causative agent of human malaria, Plasmodium falciparum, is transmitted by Anopheles mosquitoes. The malaria parasite is under intensive attack from the mosquito's innate immune system during its sporogonic development. We have used genetic engineering to create immune-enhanced Anopheles stephensi mosquitoes through blood meal-inducible expression of a transgene encoding the IMD pathway-controlled NF-kB Rel2 transcription factor in the midgut and fat-body tissue. Transgenic mosquitoes showed greater resistance to Plasmodium and microbial infection as a result of timely concerted tissue-specific immune attacks involving multiple effectors. The relatively weak impact of this genetic modification on mosquito fitness under laboratory conditions encourages further investigation of this approach for malaria control.

  18. Plasmodium falciparum-like parasites infecting wild apes in southern Cameroon do not represent a recurrent source of human malaria.

    PubMed

    Sundararaman, Sesh A; Liu, Weimin; Keele, Brandon F; Learn, Gerald H; Bittinger, Kyle; Mouacha, Fatima; Ahuka-Mundeke, Steve; Manske, Magnus; Sherrill-Mix, Scott; Li, Yingying; Malenke, Jordan A; Delaporte, Eric; Laurent, Christian; Mpoudi Ngole, Eitel; Kwiatkowski, Dominic P; Shaw, George M; Rayner, Julian C; Peeters, Martine; Sharp, Paul M; Bushman, Frederic D; Hahn, Beatrice H

    2013-04-23

    Wild-living chimpanzees and gorillas harbor a multitude of Plasmodium species, including six of the subgenus Laverania, one of which served as the progenitor of Plasmodium falciparum. Despite the magnitude of this reservoir, it is unknown whether apes represent a source of human infections. Here, we used Plasmodium species-specific PCR, single-genome amplification, and 454 sequencing to screen humans from remote areas of southern Cameroon for ape Laverania infections. Among 1,402 blood samples, we found 1,000 to be Plasmodium mitochondrial DNA (mtDNA) positive, all of which contained human parasites as determined by sequencing and/or restriction enzyme digestion. To exclude low-abundance infections, we subjected 514 of these samples to 454 sequencing, targeting a region of the mtDNA genome that distinguishes ape from human Laverania species. Using algorithms specifically developed to differentiate rare Plasmodium variants from 454-sequencing error, we identified single and mixed-species infections with P. falciparum, Plasmodium malariae, and/or Plasmodium ovale. However, none of the human samples contained ape Laverania parasites, including the gorilla precursor of P. falciparum. To characterize further the diversity of P. falciparum in Cameroon, we used single-genome amplification to amplify 3.4-kb mtDNA fragments from 229 infected humans. Phylogenetic analysis identified 62 new variants, all of which clustered with extant P. falciparum, providing further evidence that P. falciparum emerged following a single gorilla-to-human transmission. Thus, unlike Plasmodium knowlesi-infected macaques in southeast Asia, African apes harboring Laverania parasites do not seem to serve as a recurrent source of human malaria, a finding of import to ongoing control and eradication measures.

  19. Plasmodium falciparum-like parasites infecting wild apes in southern Cameroon do not represent a recurrent source of human malaria

    PubMed Central

    Sundararaman, Sesh A.; Liu, Weimin; Keele, Brandon F.; Learn, Gerald H.; Bittinger, Kyle; Mouacha, Fatima; Ahuka-Mundeke, Steve; Manske, Magnus; Sherrill-Mix, Scott; Li, Yingying; Malenke, Jordan A.; Delaporte, Eric; Laurent, Christian; Mpoudi Ngole, Eitel; Kwiatkowski, Dominic P.; Shaw, George M.; Rayner, Julian C.; Peeters, Martine; Sharp, Paul M.; Bushman, Frederic D.; Hahn, Beatrice H.

    2013-01-01

    Wild-living chimpanzees and gorillas harbor a multitude of Plasmodium species, including six of the subgenus Laverania, one of which served as the progenitor of Plasmodium falciparum. Despite the magnitude of this reservoir, it is unknown whether apes represent a source of human infections. Here, we used Plasmodium species-specific PCR, single-genome amplification, and 454 sequencing to screen humans from remote areas of southern Cameroon for ape Laverania infections. Among 1,402 blood samples, we found 1,000 to be Plasmodium mitochondrial DNA (mtDNA) positive, all of which contained human parasites as determined by sequencing and/or restriction enzyme digestion. To exclude low-abundance infections, we subjected 514 of these samples to 454 sequencing, targeting a region of the mtDNA genome that distinguishes ape from human Laverania species. Using algorithms specifically developed to differentiate rare Plasmodium variants from 454-sequencing error, we identified single and mixed-species infections with P. falciparum, Plasmodium malariae, and/or Plasmodium ovale. However, none of the human samples contained ape Laverania parasites, including the gorilla precursor of P. falciparum. To characterize further the diversity of P. falciparum in Cameroon, we used single-genome amplification to amplify 3.4-kb mtDNA fragments from 229 infected humans. Phylogenetic analysis identified 62 new variants, all of which clustered with extant P. falciparum, providing further evidence that P. falciparum emerged following a single gorilla-to-human transmission. Thus, unlike Plasmodium knowlesi-infected macaques in southeast Asia, African apes harboring Laverania parasites do not seem to serve as a recurrent source of human malaria, a finding of import to ongoing control and eradication measures. PMID:23569255

  20. Plasmodium knowlesi infection: a diagnostic challenge

    PubMed Central

    Fan, Lijia; Lee, Shir Ying; Koay, Evelyn; Harkensee, Christian

    2013-01-01

    Plasmodium knowlesi malaria is an uncommon, but highly prevalent parasitic infection in parts of Malaysia. This is the case of a 14-year-old Singaporean boy presenting to our emergency department with an 11-day history of fever following a school trip to Malaysia. Hepatosplenomegaly was the only clinical finding; laboratory tests showed thrombocytopaenia, lymphopaenia, mild anaemia and liver transaminitis. Specific malaria antigen tests were negative, but the peripheral blood film showed plasmodia with atypical features, with a parasite load of 0.5%. PCR confirmed the diagnosis of P knowlesi. The patient was successfully treated with chloroquine. The clinical course of P knowlesi malaria is indistinguishable from that of Plasmodium falciparum. This case highlights the importance of taking detailed travel history, careful examination of malaria blood films and judicious use of molecular techniques. Antigen tests alone may have missed a malaria diagnosis altogether, while blood film examination may wrongly identify the species as Plasmodium malariae or P falciparum. Third-generation PCR assays can be used to reliably identify P knowlesi. PMID:23608876

  1. Inhibition of Plasmodium Liver Infection by Ivermectin.

    PubMed

    Mendes, António M; Albuquerque, Inês S; Machado, Marta; Pissarra, Joana; Meireles, Patrícia; Prudêncio, Miguel

    2017-02-01

    Avermectins are powerful endectocides with an established potential to reduce the incidence of vector-borne diseases. Here, we show that several avermectins inhibit the hepatic stage of Plasmodium infection in vitro Notably, ivermectin potently inhibits liver infection in vivo by impairing parasite development inside hepatocytes. This impairment has a clear impact on the ensuing blood stage parasitemia, reducing disease severity and enhancing host survival. Ivermectin has been proposed as a tool to control malaria transmission because of its effects on the mosquito vector. Our study extends the effect of ivermectin to the early stages of mammalian host infection and supports the inclusion of this multipurpose drug in malaria control strategies. Copyright © 2017 Mendes et al.

  2. Inhibition of Plasmodium Liver Infection by Ivermectin

    PubMed Central

    Mendes, António M.; Albuquerque, Inês S.; Machado, Marta; Pissarra, Joana; Meireles, Patrícia

    2016-01-01

    ABSTRACT Avermectins are powerful endectocides with an established potential to reduce the incidence of vector-borne diseases. Here, we show that several avermectins inhibit the hepatic stage of Plasmodium infection in vitro. Notably, ivermectin potently inhibits liver infection in vivo by impairing parasite development inside hepatocytes. This impairment has a clear impact on the ensuing blood stage parasitemia, reducing disease severity and enhancing host survival. Ivermectin has been proposed as a tool to control malaria transmission because of its effects on the mosquito vector. Our study extends the effect of ivermectin to the early stages of mammalian host infection and supports the inclusion of this multipurpose drug in malaria control strategies. PMID:27895022

  3. No Evidence for Ape Plasmodium Infections in Humans in Gabon

    PubMed Central

    Ollomo, Benjamin; Arnathau, Céline; Roche, Benjamin; Elguero, Eric; Moukodoum, Nancy Diamella; Okougha, Alain-Prince; Mve Ondo, Bertrand; Boundenga, Larson; Houzé, Sandrine; Galan, Maxime; Nkoghé, Dieudonné; Leroy, Eric M.; Durand, Patrick; Paupy, Christophe; Renaud, François; Prugnolle, Franck

    2015-01-01

    African great apes are naturally infected by a multitude of Plasmodium species most of them recently discovered, among which several are closely related to human malaria agents. However, it is still unknown whether these animals can serve as source of infections for humans living in their vicinity. To evaluate this possibility, we analysed the nature of Plasmodium infections from a bank of 4281 human blood samples collected in 210 villages of Gabon, Central Africa. Among them, 2255 were detected positive to Plasmodium using molecular methods (Plasmodium Cytochrome b amplification). A high throughput sequencing technology (454 GS-FLX Titanium technology, Roche) was then used to identify the Plasmodium species present within each positive sample. Overall, we identified with confidence only three species infecting humans in Gabon: P. falciparum, P. malariae and P. ovale. None of the species known to infect non-human primates in Central Africa was found. Our study shows that ape Plasmodium parasites of the subgenus Laverania do not constitute a frequent source of infection for humans. It also suggests that some strong host genetic barriers must exist to prevent the cross species transmission of ape Plasmodium in a context of ever increasing contacts between humans and wildlife. PMID:26039338

  4. No evidence for ape Plasmodium infections in humans in Gabon.

    PubMed

    Délicat-Loembet, Lucresse; Rougeron, Virginie; Ollomo, Benjamin; Arnathau, Céline; Roche, Benjamin; Elguero, Eric; Moukodoum, Nancy Diamella; Okougha, Alain-Prince; Mve Ondo, Bertrand; Boundenga, Larson; Houzé, Sandrine; Galan, Maxime; Nkoghé, Dieudonné; Leroy, Eric M; Durand, Patrick; Paupy, Christophe; Renaud, François; Prugnolle, Franck

    2015-01-01

    African great apes are naturally infected by a multitude of Plasmodium species most of them recently discovered, among which several are closely related to human malaria agents. However, it is still unknown whether these animals can serve as source of infections for humans living in their vicinity. To evaluate this possibility, we analysed the nature of Plasmodium infections from a bank of 4281 human blood samples collected in 210 villages of Gabon, Central Africa. Among them, 2255 were detected positive to Plasmodium using molecular methods (Plasmodium Cytochrome b amplification). A high throughput sequencing technology (454 GS-FLX Titanium technology, Roche) was then used to identify the Plasmodium species present within each positive sample. Overall, we identified with confidence only three species infecting humans in Gabon: P. falciparum, P. malariae and P. ovale. None of the species known to infect non-human primates in Central Africa was found. Our study shows that ape Plasmodium parasites of the subgenus Laverania do not constitute a frequent source of infection for humans. It also suggests that some strong host genetic barriers must exist to prevent the cross species transmission of ape Plasmodium in a context of ever increasing contacts between humans and wildlife.

  5. Plasmodium infection decreases fecundity and increases survival of mosquitoes.

    PubMed

    Vézilier, J; Nicot, A; Gandon, S; Rivero, A

    2012-10-07

    Long-lived mosquitoes maximize the chances of Plasmodium transmission. Yet, in spite of decades of research, the effect of Plasmodium parasites on mosquito longevity remains highly controversial. On the one hand, many studies report shorter lifespans in infected mosquitoes. On the other hand, parallel (but separate) studies show that Plasmodium reduces fecundity and imply that this is an adaptive strategy of the parasite aimed at redirecting resources towards longevity. No study till date has, however, investigated fecundity and longevity in the same individuals to see whether this prediction holds. In this study, we follow for both fecundity and longevity in Plasmodium-infected and uninfected mosquitoes using a novel, albeit natural, experimental system. We also explore whether the genetic variations that arise through the evolution of insecticide resistance modulate the effect of Plasmodium on these two life-history traits. We show that (i) a reduction in fecundity in Plasmodium-infected mosquitoes is accompanied by an increase in longevity; (ii) this increase in longevity arises through a trade-off between reproduction and survival; and (iii) in insecticide-resistant mosquitoes, the slope of this trade-off is steeper when the mosquito is infected by Plasmodium (cost of insecticide resistance).

  6. Colombian Anopheles triannulatus (Diptera: Culicidae) Naturally Infected with Plasmodium spp.

    PubMed Central

    Rosero, Doris A.; Naranjo-Diaz, Nelson; Alvarez, Natalí; Cienfuegos, Astrid V.; Luckhart, Shirley

    2013-01-01

    The role of Anopheles triannulatus as a local vector has not yet been defined for malaria-endemic regions of Colombia. Therefore, the aim of this work was to detect An. triannulatus naturally infected with Plasmodium spp., as an approximation to determining its importance as malaria vector in the country. A total of 510 An. triannulatus were collected in six malaria-endemic localities of NW and SE Colombia from January 2009 to March 2011. In the NW, two specimens were naturally infected; one with Plasmodium vivax VK247, collected biting on humans and the other with Plasmodium falciparum, collected resting on cattle. In the SE, two specimens were positive for P. falciparum. Although these results show An. triannulatus naturally infected with Plasmodium, further studies are recommended to demonstrate the epidemiological importance of this species in malaria-endemic regions of Colombia. PMID:27335865

  7. Outbreak of mortality in psittacine birds in a mixed-species aviary associated with Erysipelothrix rhusiopathiae infection.

    PubMed

    Galindo-Cardiel, I; Opriessnig, T; Molina, L; Juan-Salles, C

    2012-05-01

    Erysipelothrix rhusiopathiae septicemia, associated with an increased mortality of captive psittacines in a mixed-species aviary, was diagnosed by histopathology, Gram staining, bacterial culture and sequencing, immunohistochemistry, and real-time polymerase chain reaction (PCR). Over a period of 23 days with no premonitory signs, 2 rainbow lorikeets and an eclectus parrot died. Of these birds, one lorikeet and the eclectus were submitted for necropsy. The main pathologic findings were thrombosis (2/2), bacterial embolism/thromboembolism (2/2), necrotizing hepatitis (2/2), necrohemorrhagic myocarditis (1/2), fibrinohemorrhagic and heterophilic visceral coelomitis (1/2), submandibular necrosuppurative dermatitis with necrotizing vasculitis and bacterial and fungal thromboembolism (1/2), and locally extensive rhabdomyonecrosis with bacterial embolism (1/2). Intralesional bacteria were positive by Gram staining and immunohistochemistry in both cases. E. rhusiopathiae was isolated by routine bacterial culture from the liver of the lorikeet, which was also positive by real-time PCR. This report is one of the rare descriptions of erysipelas in psittacines, and to the authors' knowledge, it appears to be the first in the described species using immunohistochemistry and real-time PCR on avian paraffin-embedded tissues for the diagnosis.

  8. Inhibition of Plasmodium sporozoites infection by targeting the host cell

    PubMed Central

    Leitao, Ricardo; Rodriguez, Ana

    2010-01-01

    There is a great need of new drugs against malaria because of the increasing spread of parasite resistance against the most commonly used drugs in the field. We found that monensin, a common veterinary antibiotic, has a strong inhibitory effect in Plasmodium berghei and P. yoelii sporozoites hepatocyte infection in vitro. Infection of host cells by another apicomplexan parasite with a similar mechanism of host cell invasion, Toxoplasma tachyzoites, was also inhibited. Treatment of mice with monensin abrogates liver infection with P. berghei sporozoites in vivo. We also found that at low concentrations monensin inhibits the infection of Plasmodium sporozoites by rendering host cells resistant to infection, rather than having a direct effect on sporozoites. Monensin effect is targeted to the initial stages of parasite invasion of the host cell with little or no effect on development, suggesting that this antibiotic affects an essential host cell component that is required for Plasmodium sporozoite invasion. PMID:20493847

  9. Plasmodium knowlesi infection imported to Germany, January 2013.

    PubMed

    Orth, H; Jensen, B O; Holtfreter, M C; Kocheril, S J; Mallach, S; MacKenzie, C; Müller-Stöver, I; Henrich, B; Imwong, M; White, N J; Häussinger, D; Richter, J

    2013-10-03

    Plasmodium knowlesi was known as a plasmodium of macaques until P. knowlesi transmission to humans was recognised in Borneo and later throughout South-East Asia. We describe here a case of a P. knowlesi infection imported to Germany from Thailand. The patient had not taken antimalarial chemoprophylaxis and suffered from daily fever attacks. Microscopy revealed trophozoites and gametocytes resembling P. malariae. P. knowlesi malaria was confirmed by PCR.

  10. Plasmodium simium/Plasmodium vivax infections in southern brown howler monkeys from the Atlantic Forest

    PubMed Central

    Costa, Daniela Camargos; da Cunha, Vanessa Pecini; de Assis, Gabriela Maria Pereira; de Souza, Júlio César; Hirano, Zelinda Maria Braga; de Arruda, Mércia Eliane; Kano, Flora Satiko; Carvalho, Luzia Helena; de Brito, Cristiana Ferreira Alves

    2014-01-01

    Blood infection by the simian parasite, Plasmodium simium, was identified in captive (n = 45, 4.4%) and in wild Alouatta clamitans monkeys (n = 20, 35%) from the Atlantic Forest of southern Brazil. A single malaria infection was symptomatic and the monkey presented clinical and haematological alterations. A high frequency of Plasmodium vivax-specific antibodies was detected among these monkeys, with 87% of the monkeys testing positive against P. vivax antigens. These findings highlight the possibility of malaria as a zoonosis in the remaining Atlantic Forest and its impact on the epidemiology of the disease. PMID:25099335

  11. Plasmodium simium/Plasmodium vivax infections in southern brown howler monkeys from the Atlantic Forest.

    PubMed

    Costa, Daniela Camargos; da Cunha, Vanessa Pecini; de Assis, Gabriela Maria Pereira; de Souza Junior, Júlio César; Hirano, Zelinda Maria Braga; de Arruda, Mércia Eliane; Kano, Flora Satiko; Carvalho, Luzia Helena; de Brito, Cristiana Ferreira Alves

    2014-08-01

    Blood infection by the simian parasite, Plasmodium simium, was identified in captive (n = 45, 4.4%) and in wild Alouatta clamitans monkeys (n = 20, 35%) from the Atlantic Forest of southern Brazil. A single malaria infection was symptomatic and the monkey presented clinical and haematological alterations. A high frequency of Plasmodium vivax-specific antibodies was detected among these monkeys, with 87% of the monkeys testing positive against P. vivax antigens. These findings highlight the possibility of malaria as a zoonosis in the remaining Atlantic Forest and its impact on the epidemiology of the disease.

  12. Wolbachia increases susceptibility to Plasmodium infection in a natural system

    PubMed Central

    Zélé, F.; Nicot, A.; Berthomieu, A.; Weill, M.; Duron, O.; Rivero, A.

    2014-01-01

    Current views about the impact of Wolbachia on Plasmodium infections are almost entirely based on data regarding artificially transfected mosquitoes. This work has shown that Wolbachia reduces the intensity of Plasmodium infections in mosquitoes, raising the exciting possibility of using Wolbachia to control or limit the spread of malaria. Whether natural Wolbachia infections have the same parasite-inhibiting properties is not yet clear. Wolbachia–mosquito combinations with a long evolutionary history are, however, key for understanding what may happen with Wolbachia-transfected mosquitoes after several generations of coevolution. We investigate this issue using an entirely natural mosquito–Wolbachia–Plasmodium combination. In contrast to most previous studies, which have been centred on the quantification of the midgut stages of Plasmodium, we obtain a measurement of parasitaemia that relates directly to transmission by following infections to the salivary gland stages. We show that Wolbachia increases the susceptibility of Culex pipiens mosquitoes to Plasmodium relictum, significantly increasing the prevalence of salivary gland stage infections. This effect is independent of the density of Wolbachia in the mosquito. These results suggest that naturally Wolbachia-infected mosquitoes may, in fact, be better vectors of malaria than Wolbachia-free ones. PMID:24500167

  13. Wolbachia increases susceptibility to Plasmodium infection in a natural system.

    PubMed

    Zélé, F; Nicot, A; Berthomieu, A; Weill, M; Duron, O; Rivero, A

    2014-03-22

    Current views about the impact of Wolbachia on Plasmodium infections are almost entirely based on data regarding artificially transfected mosquitoes. This work has shown that Wolbachia reduces the intensity of Plasmodium infections in mosquitoes, raising the exciting possibility of using Wolbachia to control or limit the spread of malaria. Whether natural Wolbachia infections have the same parasite-inhibiting properties is not yet clear. Wolbachia-mosquito combinations with a long evolutionary history are, however, key for understanding what may happen with Wolbachia-transfected mosquitoes after several generations of coevolution. We investigate this issue using an entirely natural mosquito-Wolbachia-Plasmodium combination. In contrast to most previous studies, which have been centred on the quantification of the midgut stages of Plasmodium, we obtain a measurement of parasitaemia that relates directly to transmission by following infections to the salivary gland stages. We show that Wolbachia increases the susceptibility of Culex pipiens mosquitoes to Plasmodium relictum, significantly increasing the prevalence of salivary gland stage infections. This effect is independent of the density of Wolbachia in the mosquito. These results suggest that naturally Wolbachia-infected mosquitoes may, in fact, be better vectors of malaria than Wolbachia-free ones.

  14. Plasmodium infection in a Leadbeater's possum (Gymnobelideus leadbeateri).

    PubMed

    Scheelings, T F; McLaren, P J; Tatarczuch, L; Slocombe, R F

    2016-08-01

    A wild-caught, adult female Leadbeater's possum (Gymnobelideus leadbeateri) died while in captivity after suffering from chronic ill-thrift that progressed to acute respiratory distress. On histopathological examination of tissues, the cause of death was determined to be severe acute pneumonia with pulmonary oedema associated with an intracellular protozoan parasite present within erythrocytes. Transmission electron microscopy was performed on lung tissues and organisms consistent for Plasmodium sp. were identified within numerous erythrocytes. Molecular characterisation of the parasite from DNA extracted from tissue blocks of fixed lung determined the organism to belong to the genus Plasmodium (100% similarity to Plasmodium species when a BLAST analysis was performed); however, speciation of the organism was not possible. This is the first report of Plasmodium sp. infection and subsequent disease in a native Australian mammal. The lifecycle of this parasite remains unknown. It is also unknown what effects haemoparasitism may have on the population dynamics of this endangered possum species. © 2016 Australian Veterinary Association.

  15. Plasmodium malariae Infection Associated with a High Burden of Anemia: A Hospital-Based Surveillance Study

    PubMed Central

    Lampah, Daniel A.; Simpson, Julie A.; Kenangalem, Enny; Sugiarto, Paulus; Anstey, Nicholas M.; Poespoprodjo, Jeanne Rini; Price, Ric N.

    2015-01-01

    Background Plasmodium malariae is a slow-growing parasite with a wide geographic distribution. Although generally regarded as a benign cause of malaria, it has been associated with nephrotic syndrome, particularly in young children, and can persist in the host for years. Morbidity associated with P. malariae infection has received relatively little attention, and the risk of P. malariae-associated nephrotic syndrome is unknown. Methodology/Principal Findings We used data from a very large hospital-based surveillance system incorporating information on clinical diagnoses, blood cell parameters and treatment to describe the demographic distribution, morbidity and mortality associated with P. malariae infection in southern Papua, Indonesia. Between April 2004 and December 2013 there were 1,054,674 patient presentations to Mitra Masyarakat Hospital of which 196,380 (18.6%) were associated with malaria and 5,097 were with P. malariae infection (constituting 2.6% of all malaria cases). The proportion of malaria cases attributable to P. malariae increased with age from 0.9% for patients under one year old to 3.1% for patients older than 15 years. Overall, 8.5% of patients with P. malariae infection required admission to hospital and the median length of stay for these patients was 2.5 days (Interquartile Range: 2.0–4.0 days). Patients with P. malariae infection had a lower mean hemoglobin concentration (9.0g/dL) than patients with P. falciparum (9.5g/dL), P. vivax (9.6g/dL) and mixed species infections (9.3g/dL). There were four cases of nephrotic syndrome recorded in patients with P. malariae infection, three of which were in children younger than 5 years old, giving a risk in this age group of 0.47% (95% Confidence Interval; 0.10% to 1.4%). Overall, 2.4% (n = 16) of patients hospitalized with P. malariae infection subsequently died in hospital, similar to the proportions for the other endemic Plasmodium species (range: 0% for P. ovale to 1.6% for P. falciparum

  16. Placental histopathological changes associated with Plasmodium vivax infection during pregnancy.

    PubMed

    Souza, Rodrigo M; Ataíde, Ricardo; Dombrowski, Jamille G; Ippólito, Vanessa; Aitken, Elizabeth H; Valle, Suiane N; Álvarez, José M; Epiphanio, Sabrina; Epiphânio, Sabrina; Marinho, Claudio R F

    2013-01-01

    Histological evidence of Plasmodium in the placenta is indicative of placental malaria, a condition associated with severe outcomes for mother and child. Histological lesions found in placentas from Plasmodium-exposed women include syncytial knotting, syncytial rupture, thickening of the placental barrier, necrosis of villous tissue and intervillositis. These histological changes have been associated with P. falciparum infections, but little is known about the contribution of P. vivax to such changes. We conducted a cross-sectional study with pregnant women at delivery and assigned them to three groups according to their Plasmodium exposure during pregnancy: no Plasmodium exposure (n = 41), P. vivax exposure (n = 59) or P. falciparum exposure (n = 19). We evaluated their placentas for signs of Plasmodium and placental lesions using ten histological parameters: syncytial knotting, syncytial rupture, placental barrier thickness, villi necrosis, intervillous space area, intervillous leucocytes, intervillous mononucleates, intervillous polymorphonucleates, parasitized erythrocytes and hemozoin. Placentas from P. vivax-exposed women showed little evidence of Plasmodium or hemozoin but still exhibited more lesions than placentas from women not exposed to Plasmodium, especially when infections occurred twice or more during pregnancy. In the Brazilian state of Acre, where diagnosis and primary treatment are readily available and placental lesions occur in the absence of detected placental parasites, relying on the presence of Plasmodium in the placenta to evaluate Plasmodium-induced placental pathology is not feasible. Multivariate logistic analysis revealed that syncytial knotting (odds ratio [OR], 4.21, P = 0.045), placental barrier thickness (OR, 25.59, P = 0.021) and mononuclear cells (OR, 4.02, P = 0.046) were increased in placentas from P. vivax-exposed women when compared to women not exposed to Plasmodium during pregnancy. A vivax-score was

  17. Single and mixed-species trypanosome and microsporidia infections elicit distinct, ephemeral cellular and humoral immune responses in honey bees

    USDA-ARS?s Scientific Manuscript database

    Frequently encountered parasite species impart strong selective pressures on host immune system evolution and are more apt to concurrently infect the same host, yet molecular impacts in light of this are often overlooked. We have contrasted immune responses in honey bees to two common eukaryotic en...

  18. Diagnosis of an imported Plasmodium ovale wallikeri infection in Malaysia.

    PubMed

    Liew, Jonathan Wee Kent; Mahmud, Rohela; Tan, Lian Huat; Lau, Yee Ling

    2016-01-06

    Plasmodium ovale is rare and not exactly known to be autochthonous in Malaysia. There are two distinct forms of the parasite, namely P. ovale curtisi (classic form) and P. ovale wallikeri (variant form). Here, the first sequence confirmed case of an imported P. ovale wallikeri infection in Malaysia is presented. Microscopy found Plasmodium parasites with morphology similar to P. ovale or Plasmodium vivax in the blood films. Further confirmation using polymerase chain reaction (PCR) targeting the small-subunit rRNA gene of the parasite was unsuccessful. Genus-specific PCR was then performed and the product was sequenced and analysed. Sequence analyses confirmed the aetiological agent as P. ovale wallikeri. New species-specific primers (rOVA1v and rOVA2v) were employed and P. ovale wallikeri was finally confirmed. The findings highlight the need to look out for imported malaria infections in Malaysia and the importance of a constantly updated and validated diagnostic technique.

  19. Seroepidemiology of Plasmodium species infections in Zimbabwean population.

    PubMed

    Amanfo, Seth A; Mduluza, Takafira; Midzi, Nicholas; Cavanagh, David R; Mutapi, Francisca

    2016-05-10

    additional diagnostic tools in antibody assays for the detection of exposure to the different Plasmodium species. The results also introduce an interesting concept of the co-infection of non-falciparum Plasmodium almost always with P. falciparum, which requires further validation and mechanistic studies.

  20. Susceptibility of human Plasmodium knowlesi infections to anti-malarials

    PubMed Central

    2013-01-01

    Background Evidence suggests that Plasmodium knowlesi malaria in Sarawak, Malaysian Borneo remains zoonotic, meaning anti-malarial drug resistance is unlikely to have developed in the absence of drug selection pressure. Therefore, adequate response to available anti-malarial treatments is assumed. Methods Here the ex vivo sensitivity of human P. knowlesi isolates in Malaysian Borneo were studied, using a WHO schizont maturation assay modified to accommodate the quotidian life cycle of this parasite. The in vitro sensitivities of P. knowlesi H strain adapted from a primate infection to in vitro culture (by measuring the production of Plasmodium lactate dehydrogenase) were also examined together with some assays using Plasmodium falciparum and Plasmodium vivax. Results Plasmodium knowlesi is uniformly highly sensitive to artemisinins, variably and moderately sensitive to chloroquine, and less sensitive to mefloquine. Conclusions Taken together with reports of clinical failures when P. knowlesi is treated with mefloquine, the data suggest that caution is required if using mefloquine in prevention or treatment of P. knowlesi infections, until further studies are undertaken. PMID:24245918

  1. Plasmodium knowlesi infection in humans, Cambodia, 2007-2010.

    PubMed

    Khim, Nimol; Siv, Sovannaroth; Kim, Saorin; Mueller, Tara; Fleischmann, Erna; Singh, Balbir; Divis, Paul Cliff Simon; Steenkeste, Nicolas; Duval, Linda; Bouchier, Christiane; Duong, Socheat; Ariey, Frederic; Menard, Didier

    2011-10-01

    Two cases of Plasmodium knowlesi infection in humans were identified in Cambodia by 3 molecular detection assays and sequencing. This finding confirms the widespread distribution of P. knowlesi malaria in humans in Southeast Asia. Further wide-scale studies are required to assess the public health relevance of this zoonotic malaria parasite.

  2. Plasmodium knowlesi Infection in Humans, Cambodia, 2007–2010

    PubMed Central

    Khim, Nimol; Siv, Sovannaroth; Kim, Saorin; Mueller, Tara; Fleischmann, Erna; Singh, Balbir; Divis, Paul Cliff Simon; Steenkeste, Nicolas; Duval, Linda; Bouchier, Christiane; Duong, Socheat; Ariey, Frederic

    2011-01-01

    Two cases of Plasmodium knowlesi infection in humans were identified in Cambodia by 3 molecular detection assays and sequencing. This finding confirms the widespread distribution of P. knowlesi malaria in humans in Southeast Asia. Further wide-scale studies are required to assess the public health relevance of this zoonotic malaria parasite. PMID:22000366

  3. Malaria-like symptoms associated with a natural Plasmodium reichenowi infection in a chimpanzee.

    PubMed

    Herbert, Anaïs; Boundenga, Larson; Meyer, Anne; Moukodoum, Diamella Nancy; Okouga, Alain Prince; Arnathau, Céline; Durand, Patrick; Magnus, Julie; Ngoubangoye, Barthélémy; Willaume, Eric; Ba, Cheikh Tidiane; Rougeron, Virginie; Renaud, François; Ollomo, Benjamin; Prugnolle, Franck

    2015-05-28

    Although Plasmodium infections have never been clearly associated with symptoms in non-human primates, the question of the pathogenicity of Plasmodium parasites in non-human primates still remains unanswered. A young chimpanzee, followed before and after release to a sanctuary, in a semi-free ranging enclosure located in an equatorial forest, showed fever and strong anaemia associated with a high Plasmodium reichenowi infection, shortly after release. The animal recovered from anaemia after several months despite recurrent infection with other Plasmodium species. This may be the first description of malaria-like symptoms in a chimpanzee infected with Plasmodium.

  4. Immunization of mice with Plasmodium TCTP delays establishment of Plasmodium infection.

    PubMed

    Taylor, K J; Van, T T H; MacDonald, S M; Meshnick, S R; Fernley, R T; Macreadie, I G; Smooker, P M

    2015-01-01

    Translationally controlled tumour protein (TCTP) may play an important role in the establishment or maintenance of parasitemia in a malarial infection. In this study, the potential of TCTP as a malaria vaccine was investigated in two trials. In the initial vaccine trial, Plasmodium falciparum TCTP (PfTCTP) was expressed in Saccharomyces cerevisiae and used to immunize BALB/c mice. Following challenge with Plasmodium yoelii YM, parasitemia was significantly reduced during the early stages of infection. In the second vaccine trial, the TCTP from P. yoelii and P. berghei was expressed in Escherichia coli and used in several mouse malaria models. A significant reduction in parasitemia in the early stages of infection was observed in BALB/c mice challenged with P. yoelii YM. A significantly reduced parasitemia at each day leading up to a delayed and reduced peak parasitemia was also observed in BALB/c mice challenged with the nonlethal Plasmodium chabaudi (P.c.) chabaudi AS. These results suggest that TCTP has an important role for parasite establishment and may be important for pathogenesis.

  5. Multiplicity of Infection and Disease Severity in Plasmodium vivax

    PubMed Central

    Pacheco, M. Andreína; Lopez-Perez, Mary; Vallejo, Andrés F.; Herrera, Sócrates; Arévalo-Herrera, Myriam; Escalante, Ananias A.

    2016-01-01

    Background Multiplicity of infection (MOI) refers to the average number of distinct parasite genotypes concurrently infecting a patient. Although several studies have reported on MOI and the frequency of multiclonal infections in Plasmodium falciparum, there is limited data on Plasmodium vivax. Here, MOI and the frequency of multiclonal infections were studied in areas from South America where P. vivax and P. falciparum can be compared. Methodology/Principal Findings As part of a passive surveillance study, 1,328 positive malaria patients were recruited between 2011 and 2013 in low transmission areas from Colombia. Of those, there were only 38 P. vivax and 24 P. falciparum clinically complicated cases scattered throughout the time of the study. Samples from uncomplicated cases were matched in time and location with the complicated cases in order to compare the circulating genotypes for these two categories. A total of 92 P. vivax and 57 P. falciparum uncomplicated cases were randomly subsampled. All samples were genotyped by using neutral microsatellites. Plasmodium vivax showed more multiclonal infections (47.7%) than P. falciparum (14.8%). Population genetics and haplotype network analyses did not detect differences in the circulating genotypes between complicated and uncomplicated cases in each parasite. However, a Fisher exact test yielded a significant association between having multiclonal P. vivax infections and complicated malaria. No association was found for P. falciparum infections. Conclusion The association between multiclonal infections and disease severity in P. vivax is consistent with previous observations made in rodent malaria. The contrasting pattern between P. vivax and P. falciparum could be explained, at least in part, by the fact that P. vivax infections have lineages that were more distantly related among them than in the case of the P. falciparum multiclonal infections. Future research should address the possible role that acquired

  6. Clinical and Laboratory Features of Human Plasmodium knowlesi Infection

    PubMed Central

    Daneshvar, Cyrus; Davis, Timothy M. E.; Cox-Singh, Janet; Rafa’ee, Mohammad Zakri; Zakaria, Siti Khatijah; Divis, Paul C. S.; Singh, Balbir

    2010-01-01

    Background Plasmodium knowlesi is increasingly recognized as a cause of human malaria in Southeast Asia but there are no detailed prospective clinical studies of naturally acquired infections. Methods In a systematic study of the presentation and course of patients with acute P. knowlesi infection, clinical and laboratory data were collected from previously untreated, nonpregnant adults admitted to the hospital with polymerase chain reaction–confirmed acute malaria at Kapit Hospital (Sarawak, Malaysia) from July 2006 through February 2008. Results Of 152 patients recruited, 107 (70%) had P. knowlesi infection, 24 (16%) had Plasmodium falciparum infection, and 21 (14%) had Plasmodium vivax. Patients with P. knowlesi infection presented with a nonspecific febrile illness, had a baseline median parasitemia value at hospital admission of 1387 parasites/μL (interquartile range, 6–222,570 parasites/μL), and all were thrombocytopenic at hospital admission or on the following day. Most (93.5%) of the patients with P. knowlesi infection had uncomplicated malaria that responded to chloroquine and primaquine treatment. Based on World Health Organization criteria for falciparum malaria, 7 patients with P. knowlesi infection (6.5%) had severe infections at hospital admission. The most frequent complication was respiratory distress, which was present at hospital admission in 4 patients and developed after admission in an additional 3 patients. P. knowlesi parasitemia at hospital admission was an independent determinant of respiratory distress, as were serum creatinine level, serum bilirubin, and platelet count at admission (P < .002 for each). Two patients with knowlesi malaria died, representing a case fatality rate of 1.8% (95% confidence interval, 0.2%–6.6%). Conclusions Knowlesi malaria causes a wide spectrum of disease. Most cases are uncomplicated and respond promptly to treatment, but approximately 1 in 10 patients develop potentially fatal complications. PMID

  7. Human Plasmodium knowlesi Infection Detected by Rapid Diagnostic Tests for Malaria

    PubMed Central

    van Hellemond, Jaap J.; Rutten, Marijke; Koelewijn, Rob; Zeeman, Anne-Marie; Verweij, Jaco J.; Wismans, Pieter J.; Kocken, Clemens H.

    2009-01-01

    We describe a PCR-confirmed case of Plasmodium knowlesi infection with a high parasitemia level and clinical signs of severe malaria in a migrant worker from Malaysian Borneo in the Netherlands. Investigations showed that commercially available rapid antigen tests for detection of human Plasmodium infections can detect P. knowlesi infections in humans. PMID:19788819

  8. Blood schizontocidal activity of WR 238605 (Tafenoquine) against Plasmodium cynomolgi and Plasmodium fragile infections in rhesus monkeys.

    PubMed

    Puri, S K; Dutta, G P

    2003-04-01

    A new 8-aminoquinoline antimalarial WR 238605 (Tafenoquine), developed initially as a primaquine alternative for prevention of Plasmodium vivax relapses was evaluated for blood schizontocidal activity against two simian malaria infections namely Plasmodium cynomolgi B and Plasmodium fragile in rhesus monkeys. Treatment with WR 238605 at a dose of 3.16 mg(base)/kg/day x 7 days cured established trophozoite induced infections in monkeys with both these parasites. The lower dose of 1.00 mg/kg/day cured 9 out of 12 monkeys infected with P. cynomolgi B and 10 out of 11 monkeys infected with P. fragile. Primaquine was only partially curative at 10.0 mg(base)/kg/day x 7 dose regimen against both these infections. The potent blood schizontocidal activity of tafenoquine adds to the armoury of antimalarial drugs.

  9. Acute kidney injury associated with Plasmodium malariae infection.

    PubMed

    Badiane, Aida S; Diongue, Khadim; Diallo, Seydou; Ndongo, Aliou A; Diedhiou, Cyrille K; Deme, Awa B; Ma, Diallo; Ndiaye, Mouhamadou; Seck, Mame C; Dieng, Therese; Ndir, Omar; Mboup, Souleymane; Ndiaye, Daouda

    2014-06-07

    According to current estimates, Plasmodium malariae is not very common in Senegal, as more than 98% of malaria cases are suspected to be due to Plasmodium falciparum. However, it is possible that other malarial species are being under-reported or misdiagnosed. This is a report of a case of P. malariae in a 30-year-old man previously hospitalized with acute kidney injury after treatment with quinine and re-hospitalized three months later. He was diagnosed with renal cortical necrosis post malaria treatment. Plasmodium malariae was identified with light microscope and confirmed using species-specific small-subunit rRNA (ssrRNA) amplification.The patient was treated for malaria with intravenous quinine for seven days, followed by three days of oral treatment; the bacterial infection was treated using ceftriaxone during the first hospitalization and ciprofloxacin associated with ceftriaxone the second time. He also had four rounds of dialysis after which he partially recovered the renal function. Given the complications that can be caused by P. malariae infection, it should be systematically looked for, even if the predominant species is P. falciparum in Senegal.

  10. [Monkey malaria (Plasmodium knowlesi infection) after travelling to Thailand].

    PubMed

    Kroidl, Inge; Seilmaier, Michael; Berens-Riha, Nicole; Bretzel, Gisela; Wendtner, Clemens; Löscher, Thomas

    2015-05-01

    A case of malaria caused by Plasmodium knowlesi is described in a 52-year-old female German traveler after returning from Thailand. P. knowlesi is a parasite of macaques in Southeast Asia and has been recognized in recent years as an important and probably increasing cause of human malaria in some areas. At least 16 cases in international travelers have been published so far. This includes four cases imported to Germany. All German patients visited forested areas in Southern Thailand inhabited by the natural monkey host prior to their illness. Most cases diagnosed in endemic areas present as mild disease. However in some patients P. knowlesi may take a severe and life-threatening course. Diagnosis is usually is based on microscopy whereas rapid tests are not reliable. However, microscopic differentiation of P. knowlesi from other plasmodium species (eg, P. malariae, P. falciparum) is difficult, especially when parasitemia is low. Thus PCR methods are required for definite species determination. Changing endemicity as well as changing tourism patterns such as the trend towards eco-tourism might increase the risk of infection for travelers even in areas which are considered as low endemic for malaria. Malaria has to be considered in all febrile patients returning from endemic areas. In Southeast Asia this has to include Plasmodium knowlesi infection. Especially if microscopy suggests P. falciparum/P. malariae double infection, or when results indicate P. malariae but the clinical presentation differs from that of quartan malaria (eg, daily fever), diagnostic procedures for P. knowlesi should be initiated. Currently available rapid diagnostic tests are not reliable for the detection of P. knowlesi. The definite diagnosis of P. knowlesi infection usually requires PCR techniques Changing tourism patterns such as the trend towards eco-tourism might increase the risk of infection for travelers even in low prevalence areas.

  11. Plasmodium falciparum and Plasmodium vivax infections in the owl monkey (Aotus trivirgatus). I. The courses of untreated infections.

    PubMed

    Schmidt, L H

    1978-07-01

    This study, the first of three designed to determine the feasibility of using owl monkeys infected with human plasmodia in the search for new, more broadly active antimalarial drugs, dealt with the characteristics of untreated infections with eight strains of Plasmodium falciparum and two strains of P. vivax. Such infections, induced by standardized inocula of these strains in 1,733 monkeys, all Aotus trivirgatus griseimembra, were followed from day of inoculation to death of self-cure. The virulence of the various strains differed strikingly. Incidences of fatal reactions, ranging from 24.4--89.4% and 8.1--45.8%, respectively, in infections with strains of P. falciparum and P. vivax, were closely related to the rate at which parasitemia evolved, the height of parasitemia in the primary attack, and/or the time period over which a high parasite level was sustained. Antemortem symptom complexes and gross tissue and organ reactions in infections with P. falciparum varied with survival time, but within that boundary, were the same for infections with all eight strains of this plasmodium. Morbidity in both fatal and self-limited infections with both plasmodial species was related to height of parasitemia; however, at comparable parasite levels, symptoms exhibited in infections with P. vivax were more severe than in infections with P. falciparum. Overall, the characteristics of infections with these plasmodia in owl monkeys were remarkably similar to those of human infections. With respect to biological features, infections with P. falciparum and P. vivax in this simian host appear to have much to offer in the search for new antimalarial drugs.

  12. Malaria parasites (Plasmodium spp.) infecting introduced, native and endemic New Zealand birds.

    PubMed

    Howe, Laryssa; Castro, Isabel C; Schoener, Ellen R; Hunter, Stuart; Barraclough, Rosemary K; Alley, Maurice R

    2012-02-01

    Avian malaria is caused by intracellular mosquito-transmitted protist parasites in the order Haemosporida, genus Plasmodium. Although Plasmodium species have been diagnosed as causing death in several threatened species in New Zealand, little is known about their ecology and epidemiology. In this study, we examined the presence, microscopic characterization and sequence homology of Plasmodium spp. isolates collected from a small number of New Zealand introduced, native and endemic bird species. We identified 14 Plasmodium spp. isolates from 90 blood or tissue samples. The host range included four species of passerines (two endemic, one native, one introduced), one species of endemic pigeon and two species of endemic kiwi. The isolates were associated into at least four distinct clusters including Plasmodium (Huffia) elongatum, a subgroup of Plasmodium elongatum, Plasmodium relictum and Plasmodium (Noyvella) spp. The infected birds presented a low level of peripheral parasitemia consistent with chronic infection (11/15 blood smears examined). In addition, we report death due to overwhelming parasitemia in a blackbird, a great spotted kiwi and a hihi. These deaths were attributed to infections with either Plasmodium spp. lineage LINN1 or P. relictum lineage GRW4. To the authors' knowledge, this is the first published report of Plasmodium spp. infection in great spotted and brown kiwi, kereru and kokako. Currently, we are only able to speculate on the origin of these 14 isolates but consideration must be made as to the impact they may have on threatened endemic species, particularly due to the examples of mortality.

  13. Minireview: Invasive fungal infection complicating acute Plasmodium falciparum malaria.

    PubMed

    Däbritz, Jan; Schneider, Markward; Just-Nuebling, Gudrun; Groll, Andreas H

    2011-07-01

    Malaria is the most important parasitic infection in people, affecting 5-10% of the world's population with more than two million deaths a year. Whereas invasive bacterial infections are not uncommon during severe Plasmodium falciparum malaria, only a few cases of opportunistic fungal infections have been reported. Here, we present a fatal case of disseminated hyalohyphomycosis associated with acute P. falciparum malaria in a non-immune traveller, review the cases reported in the literature and discuss the theoretical foundations for the increased susceptibility of non-immune individuals with severe P. falciparum malaria to opportunistic fungal infections. Apart from the availability of free iron as sequelae of massive haemolysis, tissue damage, acidosis and measures of advanced life support, patients with complicated P. falciparum malaria also are profoundly immunosuppressed by the organism's interaction with innate and adaptive host immune mechanisms.

  14. Natural Plasmodium infections in Brazilian wild monkeys: reservoirs for human infections?

    PubMed

    Duarte, Ana Maria Ribeiro de Castro; Malafronte, Rosely dos Santos; Cerutti, Crispim; Curado, Izilda; de Paiva, Byanca Regina; Maeda, Adriana Yurika; Yamasaki, Tasciane; Summa, Maria Eugênia Laurito; Neves, Dafne do Valle Dutra de Andrade; de Oliveira, Salma Gomes; Gomes, Almério de Castro

    2008-08-01

    Four hundred and forty-eight samples of total blood from wild monkeys living in areas where human autochthonous malaria cases have been reported were screened for the presence of Plasmodium using microscopy and PCR analysis. Samples came from the following distinct ecological areas of Brazil: Atlantic forest (N=140), semideciduous Atlantic forest (N=257) and Cerrado (a savannah-like habitat) (N=51). Thick and thin blood smears of each specimen were examined and Plasmodium infection was screened by multiplex polymerase chain reaction (multiplex PCR). The frequency of Plasmodium infections detected by PCR in Alouatta guariba clamitans in the São Paulo Atlantic forest was 11.3% or 8/71 (5.6% for Plasmodium malariae and 5.6% for Plasmodium vivax) and one specimen was positive for Plasmodium falciparum (1.4%); Callithrix sp. (N=30) and Cebus apella (N=39) specimens were negative by PCR tests. Microscopy analysis was negative for all specimens from the Atlantic forest. The positivity rate for Alouatta caraya from semideciduous Atlantic forest was 6.8% (16/235) in the PCR tests (5.5, 0.8 and 0.4% for P. malariae, P. falciparum and P. vivax, respectively), while C. apella specimens were negative. Parasitological examination of the samples using thick smears revealed Plasmodium sp. infections in only seven specimens, which had few parasites (3.0%). Monkeys from the Cerrado (a savannah-like habitat) (42 specimens of A. caraya, 5 of Callithrix jacchus and 4 of C. apella) were negative in both tests. The parasitological prevalence of P. vivax and P. malariae in wild monkeys from Atlantic forest and semideciduous Atlantic forest and the finding of a positive result for P. falciparum in Alouatta from both types of forest support the hypothesis that monkeys belonging to this genus could be a potential reservoir. Furthermore, these findings raise the question of the relationship between simian and autochthonous human malaria in extra-Amazonian regions.

  15. Sequential Plasmodium chabaudi and Plasmodium berghei infections provide a novel model of severe malarial anemia.

    PubMed

    Harris, Juliana V; Bohr, Tiffany M; Stracener, Catherine; Landmesser, Mary E; Torres, Vladimir; Mbugua, Amos; Moratz, Chantal; Stoute, José A

    2012-09-01

    Lack of an adequate animal model of Plasmodium falciparum severe malarial anemia (SMA) has hampered the understanding of this highly lethal condition. We developed a model of SMA by infecting C57BL/6 mice with P. chabaudi followed after recovery by P. berghei infection. P. chabaudi/P. berghei-infected mice had an initial 9- to 10-day phase of relatively low parasitemia and severe anemia, followed by a second phase of hyperparasitemia, more profound anemia, reticulocytosis, and death 14 to 21 days after infection. P. chabaudi/P. berghei-infected animals had more intense splenic hematopoiesis, higher interleukin-10 (IL-10)/tumor necrosis factor alpha and IL-12/gamma interferon (IFN-γ) ratios, and higher antibody levels against P. berghei and P. chabaudi antigens than P. berghei-infected or P. chabaudi-recovered animals. Early treatment with chloroquine or artesunate did not prevent the anemia, suggesting that the bulk of red cell destruction was not due to the parasite. Red cells from P. chabaudi/P. berghei-infected animals had increased surface IgG and C3 by flow cytometry. However, C3(-/-) mice still developed anemia. Tracking of red cells labeled ex vivo and in vivo and analysis of frozen tissue sections by immunofluorescence microscopy showed that red cells from P. chabaudi/P. berghei-infected animals were removed at an accelerated rate in the liver by erythrophagocytosis. This model is practical and reproducible, and its similarities with P. falciparum SMA in humans makes it an appealing system with which to study the pathogenesis of this condition and explore potential immunomodulatory interventions.

  16. Species and genotype diversity of Plasmodium in malaria patients from Gabon analysed by next generation sequencing.

    PubMed

    Lalremruata, Albert; Jeyaraj, Sankarganesh; Engleitner, Thomas; Joanny, Fanny; Lang, Annika; Bélard, Sabine; Mombo-Ngoma, Ghyslain; Ramharter, Michael; Kremsner, Peter G; Mordmüller, Benjamin; Held, Jana

    2017-10-03

    Six Plasmodium species are known to naturally infect humans. Mixed species infections occur regularly but morphological discrimination by microscopy is difficult and multiplicity of infection (MOI) can only be evaluated by molecular methods. This study investigated the complexity of Plasmodium infections in patients treated for microscopically detected non-falciparum or mixed species malaria in Gabon. Ultra-deep sequencing of nucleus (18S rRNA), mitochondrion, and apicoplast encoded genes was used to evaluate Plasmodium species diversity and MOI in 46 symptomatic Gabonese patients with microscopically diagnosed non-falciparum or mixed species malaria. Deep sequencing revealed a large complexity of confections in patients with uncomplicated malaria, both on species and genotype levels. Mixed infections involved up to four parasite species (Plasmodium falciparum, Plasmodium malariae, Plasmodium ovale curtisi, and P. ovale wallikeri). Multiple genotypes from each species were determined from the asexual 18S rRNA gene. 17 of 46 samples (37%) harboured multiple genotypes of at least one Plasmodium species. The number of genotypes per sample (MOI) was highest in P. malariae (n = 4), followed by P. ovale curtisi (n = 3), P. ovale wallikeri (n = 3), and P. falciparum (n = 2). The highest combined genotype complexity in samples that contained mixed-species infections was seven. Ultra-deep sequencing showed an unexpected breadth of Plasmodium species and within species diversity in clinical samples. MOI of P. ovale curtisi, P. ovale wallikeri and P. malariae infections were higher than anticipated and contribute significantly to the burden of malaria in Gabon.

  17. Larval diet affects mosquito development and permissiveness to Plasmodium infection

    PubMed Central

    Linenberg, Inbar; Christophides, George K.; Gendrin, Mathilde

    2016-01-01

    The larval stages of malaria vector mosquitoes develop in water pools, feeding mostly on microorganisms and environmental detritus. Richness in the nutrient supply to larvae influences the development and metabolism of larvae and adults. Here, we investigated the effects of larval diet on the development, microbiota content and permissiveness to Plasmodium of Anopheles coluzzii. We tested three fish diets often used to rear mosquitoes in the laboratory, including two pelleted diets, Dr. Clarke’s Pool Pellets and Nishikoi Fish Pellets, and one flaked diet, Tetramin Fish-Flakes. Larvae grow and develop faster and produce bigger adults when feeding on both types of pellets compared with flakes. This correlates with a higher microbiota load in pellet-fed larvae, in agreement with the known positive effect of the microbiota on mosquito development. Larval diet also significantly influences the prevalence and intensity of Plasmodium berghei infection in adults, whereby Nishikoi Fish Pellets-fed larvae develop into adults that are highly permissive to parasites and survive longer after infection. This correlates with a lower amount of Enterobacteriaceae in the midgut microbiota. Together, our results shed light on the influence of larval feeding on mosquito development, microbiota and vector competence; they also provide useful data for mosquito rearing. PMID:27910908

  18. Major Histocompatibility Complex and Malaria: Focus on Plasmodium vivax Infection

    PubMed Central

    Lima-Junior, Josué da Costa; Pratt-Riccio, Lilian Rose

    2016-01-01

    The importance of host and parasite genetic factors in malaria resistance or susceptibility has been investigated since the middle of the last century. Nowadays, of all diseases that affect man, malaria still plays one of the highest levels of selective pressure on human genome. Susceptibility to malaria depends on exposure profile, epidemiological characteristics, and several components of the innate and adaptive immune system that influences the quality of the immune response generated during the Plasmodium lifecycle in the vertebrate host. But it is well known that the parasite’s enormous capacity of genetic variation in conjunction with the host genetics polymorphism is also associated with a wide spectrum of susceptibility degrees to complicated or severe forms of the disease. In this scenario, variations in genes of the major histocompatibility complex (MHC) associated with host resistance or susceptibility to malaria have been identified and used as markers in host–pathogen interaction studies, mainly those evaluating the impact on the immune response, acquisition of resistance, or increased susceptibility to infection or vulnerability to disease. However, due to the intense selective pressure, number of cases, and mortality rates, the majority of the reported associations reported concerned Plasmodium falciparum malaria. Studies on the MHC polymorphism and its association with Plasmodium vivax, which is the most widespread Plasmodium and the most prevalent species outside the African continent, are less frequent but equally important. Despite punctual contributions, there are accumulated evidences of human genetic control in P. vivax infection and disease. Herein, we review the current knowledge in the field of MHC and derived molecules (HLA Class I, Class II, TNF-α, LTA, BAT1, and CTL4) regarding P. vivax malaria. We discuss particularly the results of P. vivax studies on HLA class I and II polymorphisms in relation to host susceptibility, naturally

  19. Plasmodium infection alters Anopheles gambiae detoxification gene expression

    PubMed Central

    2010-01-01

    Background Anopheles gambiae has been shown to change its global gene expression patterns upon Plasmodium infection. While many alterations are directly related to the mosquito's innate immune response, parasite invasion is also expected to generate toxic by-products such as free radicals. The current study aimed at identifying which loci coding for detoxification enzymes are differentially expressed as a function of Plasmodium berghei infection in midgut and fat body tissues. Results Using a custom-made DNA microarray, transcript levels of 254 loci primarily belonging to three major detoxification enzyme families (glutathione S-transferases, cytochrome P450 monooxygenases and esterases) were compared in infected and uninfected mosquitoes both during ookinete invasion and the release of sporozoites into the hemocoel. The greatest changes in gene expression were observed in the midgut in response to ookinete invasion. Interestingly, many detoxification genes including a large number of P450s were down-regulated at this stage. In the fat body, while less dramatic, gene expression alterations were also observed and occurred during the ookinete invasion and during the release of sporozoites into the hemocoel. While most gene expression changes were tissue-related, CYP6M2, a CYP previously associated with insecticide resistance, was over-expressed both in the midgut and fat body during ookinete invasion. Conclusions Most toxicity-related reactions occur in the midgut shortly after the ingestion of an infected blood meal. Strong up-regulation of CYP6M2 in the midgut and the fat body as well as its previous association with insecticide resistance shows its broad role in metabolic detoxification. PMID:20482856

  20. Thrombocytopenia in Plasmodium falciparum, Plasmodium vivax and mixed infection malaria: a study from Bikaner (Northwestern India).

    PubMed

    Kochar, Dhanpat Kumar; Das, Ashis; Kochar, Abhishek; Middha, Sheetal; Acharya, Jyoti; Tanwar, Gajanand Singh; Gupta, Anjana; Pakalapati, Deepak; Garg, Shilpi; Saxena, Vishal; Subudhi, Amit Kumar; Boopathi, P A; Sirohi, Parmendra; Kochar, Sanjay Kumar

    2010-01-01

    The occurrence, relation and magnitude of thrombocytopenia in different species of malaria are not clearly defined. This study included 1,064 patients admitted with malaria to study thrombocytopenia (platelet count <150,000 /cumm) in Plasmodium falciparum (Pf) and Plasmodium vivax (Pv) mono infection and mixed infection (Pf + Pv). The species diagnosis was done by peripheral blood film (PBF) and rapid diagnostic test (RDT). Validation by polymerase chain reaction (PCR) was done only in patients with severe thrombocytopenia (platelet count <20,000 /cumm). The breakup of patients was 525 (49.34%) Pf, 460 (43.23%) Pv and 79 (7.42%) mixed malaria (Pf + Pv). Thrombocytopenia was observed in 24.6% (262/1064) patients. The risk was greatest in the mixed infections in comparison to monoinfection individually (43.04% [34/79]; mixed vs Pv monoinfection: Odds Ratio [OR] = 1.675 [95% Confidence Interval (CI) 1.029-2.726], p < 0.0366; mixed vs Pf monoinfection: OR=3.911 [95% CI 2.367-6.463], p < 0.0001). Pv monoinfection (31.09% [143/460]) had greater risk compared to Pf monoinfection (16.19% [85/525]; OR = 2.335 [95% CI 1.722-3.167], p < 0.0001). The occurrence of severe thrombocytopenia was also higher in Pv monoinfection (18.18% [26/143]) in comparison to either Pf monoinfection (10.59% [9/85], OR = 1.877 (95% CI 0.834-4.223)) or mixed infection (11.76% [4/34]; OR = 1.667 (95% CI 0.540-5.142) but this association was statistically not significant. Six patients (3 Pv, 2 Pf and 1 mixed) developed severe epistaxis requiring platelet transfusion. There was no relation between parasite density and platelet count as many patients with severe thrombocytopenia had parasite density similar to patients without thrombocytopenia. We found that the association of thrombocytopenia was statistically more significant with P. vivax monoinfection as compared to P. falciparum.

  1. Plasmodium infection, anaemia and mosquito net use among school children across different settings in Kenya.

    PubMed

    Gitonga, Caroline W; Edwards, Tansy; Karanja, Peris N; Noor, Abdisalan M; Snow, Robert W; Brooker, Simon J

    2012-07-01

    To investigate risk factors, including reported net use, for Plasmodium infection and anaemia among school children and to explore variations in effects across different malaria ecologies occurring in Kenya. This study analysed data for 49 975 school children in 480 schools surveyed during a national school malaria survey, 2008-2010. Mixed effects logistic regression was used to investigate factors associated with Plasmodium infection and anaemia within different malaria transmission zones. Insecticide-treated net (ITN) use was associated with reduction in the odds of Plasmodium infection in coastal and western highlands epidemic zones and among boys in the lakeside high transmission zone. Other risk factors for Plasmodium infection and for anaemia also varied by zone. Plasmodium infection was negatively associated with increasing socio-economic status in all transmission settings, except in the semi-arid north-east zone. Plasmodium infection was a risk factor for anaemia in lakeside high transmission, western highlands epidemic and central low-risk zones, whereas ITN use was only associated with lower levels of anaemia in coastal and central zones and among boys in the lakeside high transmission zone. The risk factors for Plasmodium infection and anaemia, including the protective associations with ITN use, vary according to malaria transmission settings in Kenya, and future efforts to control malaria and anaemia should take into account such heterogeneities among school children. © 2012 Blackwell Publishing Ltd.

  2. Augmented plasma microparticles during acute Plasmodium vivax infection

    PubMed Central

    2010-01-01

    Background In the last few years, the study of microparticles (MPs) - submicron vesicles released from cells upon activation or apoptosis - has gained growing interest in the field of inflammation and in infectious diseases. Their role in the human malaria parasite Plasmodium vivax remains unexplored. Because acute vivax malaria has been related to pro-inflammatory responses, the main hypothesis investigated in this study was that Plasmodium vivax infection is associated with elevated levels of circulating MPs, which may play a role during acute disease in non-immune patients. Methods Plasma MPs were analysed among thirty-seven uncomplicated P. vivax infections from an area of unstable malaria transmission in the Brazilian Amazon. The MP phenotype was analysed by flow cytometry using the classical MP marker, annexin, and fluorochrome-labeled monoclonal antibodies against specific cell surface markers. The frequencies of plasma MPs in P. vivax patients (n = 37) were further compared to malaria-unexposed controls (n = 15) and ovarian carcinoma patients (n = 12), a known MPs-inducing disease non-related to malaria. Results The frequencies of plasma circulating MPs were markedly increased in P. vivax patients, as compared to healthy age-matched malaria-unexposed controls. Although platelets, erythrocytes and leukocytes were the main cellular sources of MPs during vivax malaria, platelet derived-MPs (PMPs) increased in a linear fashion with the presence of fever at the time of blood collection (β = 0.06, p < 0.0001) and length of acute symptoms (β = 0.36, p < 0.0001). Finally, the results suggest that plasma levels of PMPs diminish as patient experience more episodes of clinical malaria (β = 0.07, p < 0.003). Conclusions Abundant circulating MPs are present during acute P. vivax infection, and platelet derived-MPs may play a role on the acute inflammatory symptoms of malaria vivax. PMID:21080932

  3. Volatile organic compounds associated with Plasmodium falciparum infection in vitro.

    PubMed

    Correa, Ricardo; Coronado, Lorena M; Garrido, Anette C; Durant-Archibold, Armando A; Spadafora, Carmenza

    2017-05-02

    In order to identify new ways to prevent transmission of vector-borne diseases such as malaria, efforts have been made to understand how insects are attracted to humans. Vector-host interaction studies have shown that several volatile compounds play an important role in attracting mosquitoes to human targets. A headspace solid-phase micro-extraction/gas chromatography-mass spectrometry (HSPME GC-MS) analysis of the volatile organic composition of extracellular vesicles (EVs) and supernatants of ultracentrifugation (SNUs) was carried out in Plasmodium falciparum-infected cultures with high and low parasitemias. A list of 18 volatile organic compounds (VOCs) was obtained from the EVs of both infected and uninfected RBCs with 1,2,3-Propanetriol, diacetate (diacetin) increased in the infected EVs, regardless of the parasitemia of the culture. The supernatant analysis, however, gave off 56 VOCs, with pentane 2,2,4-trimethyl being present in all the SNUs of uninfected erythrocytes but absent from the parasite-infected ones. Standing out in this study was hexanal, a reported insect attractant, which was the only VOC present in all samples from SNUs from infected erythrocytes and absent from uninfected ones, suggesting that it originates during parasite infection. The hexanal compound, reportedly a low-level component found in healthy human samples such as breath and plasma, had not been found in previous analyses of P. falciparum-infected patients or cultures. This compound has been reported as an Anopheles gambiae attractant in plants. While the compound could be produced during infection by the malaria parasite in human erythrocytes, the A. gambiae attraction could be used by the parasite as a strategy for transmission.

  4. The Dynamics of Naturally Acquired Immunity to Plasmodium falciparum Infection

    PubMed Central

    Pinkevych, Mykola; Petravic, Janka; Chelimo, Kiprotich; Kazura, James W.; Moormann, Ann M.; Davenport, Miles P.

    2012-01-01

    Severe malaria occurs predominantly in young children and immunity to clinical disease is associated with cumulative exposure in holoendemic settings. The relative contribution of immunity against various stages of the parasite life cycle that results in controlling infection and limiting disease is not well understood. Here we analyse the dynamics of Plasmodium falciparum malaria infection after treatment in a cohort of 197 healthy study participants of different ages in order to model naturally acquired immunity. We find that both delayed time-to-infection and reductions in asymptomatic parasitaemias in older age groups can be explained by immunity that reduces the growth of blood stage as opposed to liver stage parasites. We found that this mechanism would require at least two components – a rapidly acting strain-specific component, as well as a slowly acquired cross-reactive or general immunity to all strains. Analysis and modelling of malaria infection dynamics and naturally acquired immunity with age provides important insights into what mechanisms of immune control may be harnessed by malaria vaccine strategists. PMID:23093922

  5. Complexity of Infection and Genetic Diversity in Cambodian Plasmodium vivax

    PubMed Central

    Friedrich, Lindsey R.; Popovici, Jean; Kim, Saorin; Dysoley, Lek; Zimmerman, Peter A.; Menard, Didier; Serre, David

    2016-01-01

    Background Plasmodium vivax is the most widely distributed human malaria parasite with 2.9 billion people living in endemic areas. Despite intensive malaria control efforts, the proportion of cases attributed to P. vivax is increasing in many countries. Genetic analyses of the parasite population and its dynamics could provide an assessment of the efficacy of control efforts, but, unfortunately, these studies are limited in P. vivax by the lack of informative markers and high-throughput genotyping methods. Methodology/Principal Findings We developed a sequencing-based assay to simultaneously genotype more than 100 SNPs and applied this approach to ~500 P. vivax-infected individuals recruited across nine locations in Cambodia between 2004 and 2013. Our analyses showed that the vast majority of infections are polyclonal (92%) and that P. vivax displays high genetic diversity in Cambodia without apparent geographic stratification. Interestingly, our analyses also revealed that the proportion of monoclonal infections significantly increased between 2004 and 2013, possibly suggesting that malaria control strategies in Cambodia may be successfully affecting the parasite population. Conclusions/Significance Our findings demonstrate that this high-throughput genotyping assay is efficient in characterizing P. vivax diversity and can provide valuable insights to assess the efficacy of malaria elimination programs or to monitor the spread of specific parasites. PMID:27018585

  6. Differential role of T regulatory and Th17 in Swiss mice infected with Plasmodium berghei ANKA and Plasmodium yoelii.

    PubMed

    Keswani, Tarun; Bhattacharyya, Arindam

    2014-06-01

    The outcome of malaria infection is determined, in part, by the balance of pro-inflammatory and regulatory immune responses. Host immune responses in disease including malaria are finely regulated by the opposing effects of Th17 and T regulatory (Treg) cells. Here we have examined the role of Treg cells and Th17 cells during malaria infection and find that low levels of Treg cells possibly influence the outcome of infections with the lethal strain of Plasmodium berghei ANKA (PbA). In contrast, high level of Treg cells may influence the outcome of nonlethal Plasmodium yoelii NXL (P. yoelii) infections. We observed decreased expressions of key regulators of Treg inductions-TGF-β, CD4IL-2 and IL-10 during PbA infection, whereas their expression remains high during P. yoelii infection. On the other hand TNF-α, IL-6, IFN-γ and IL-23 expression is high during PbA infection and lower during P. yoelii infection. Thus, results from this study suggest that the differential expression of Treg and Th17 might have a key role on host pathogenesis during malaria infection. The high level of IL-6 and low level of TGF-β may composite of the advantaged local microenvironment for the production of Th17 cells in the spleen of the PBA infected mice and vice verse during nonlethal P. yoelii.

  7. Susceptibility to Plasmodium liver stage infection is altered by hepatocyte polyploidy

    PubMed Central

    Austin, Laura S.; Kaushansky, Alexis; Kappe, Stefan H.I.

    2014-01-01

    Summary Plasmodium parasites infect hepatocytes of their mammalian hosts and within undergo obligate liver stage development. The specific host cell attributes that are important for liver infection remain largely unknown. Several host signaling pathways are perturbed in infected hepatocytes, some of which are important in the generation of hepatocyte polyploidy. To test the functional consequence of polyploidy in liver infection, we infected hepatocytes with the rodent malaria parasite Plasmodium yoelii both in vitro and in vivo and examined the ploidy of infected and uninfected hepatocytes by flow cytometry. In both hepatoma cell lines and in the mouse liver, the fraction of polyploid cells was higher in the infected cell population than in the uninfected cell population. When the data were reanalyzed by comparing the extent of Plasmodium infection within each ploidy subset, we found that infection rates were elevated in more highly polyploid cells and lower in diploid cells. Furthermore, we found that the parasite’s preference for host cells with high ploidy is conserved among rodent malaria species and the human malaria parasite Plasmodium falciparum. This parasite preference for host cells of high ploidy cannot be explained by differences in hepatocyte size or DNA replication. We conclude that Plasmodium preferentially infects and develops in polyploid hepatocytes. PMID:24612025

  8. Antibody-independent mechanisms regulate the establishment of chronic Plasmodium infection.

    PubMed

    Brugat, Thibaut; Reid, Adam James; Lin, Jing-Wen; Cunningham, Deirdre; Tumwine, Irene; Kushinga, Garikai; McLaughlin, Sarah; Spence, Philip; Böhme, Ulrike; Sanders, Mandy; Conteh, Solomon; Bushell, Ellen; Metcalf, Tom; Billker, Oliver; Duffy, Patrick E; Newbold, Chris; Berriman, Matthew; Langhorne, Jean

    2017-02-06

    Malaria is caused by parasites of the genus Plasmodium. All human-infecting Plasmodium species can establish long-lasting chronic infections(1-5), creating an infectious reservoir to sustain transmission(1,6). It is widely accepted that the maintenance of chronic infection involves evasion of adaptive immunity by antigenic variation(7). However, genes involved in this process have been identified in only two of five human-infecting species: Plasmodium falciparum and Plasmodium knowlesi. Furthermore, little is understood about the early events in the establishment of chronic infection in these species. Using a rodent model we demonstrate that from the infecting population, only a minority of parasites, expressing one of several clusters of virulence-associated pir genes, establishes a chronic infection. This process occurs in different species of parasites and in different hosts. Establishment of chronicity is independent of adaptive immunity and therefore different from the mechanism proposed for maintenance of chronic P. falciparum infections(7-9). Furthermore, we show that the proportions of parasites expressing different types of pir genes regulate the time taken to establish a chronic infection. Because pir genes are common to most, if not all, species of Plasmodium(10), this process may be a common way of regulating the establishment of chronic infections.

  9. Sickle Cell Trait Protects Against Plasmodium falciparum Infection

    PubMed Central

    Billo, Mounkaila A.; Johnson, Eric S.; Doumbia, Seydou O.; Poudiougou, Belco; Sagara, Issaka; Diawara, Sory I.; Diakité, Mahamadou; Diallo, Mouctar; Doumbo, Ogobara K.; Tounkara, Anatole; Rice, Janet; James, Mark A.; Krogstad, Donald J.

    2012-01-01

    Although sickle cell trait protects against severe disease due to Plasmodium falciparum, it has not been clear whether sickle trait also protects against asymptomatic infection (parasitemia). To address this question, the authors identified 171 persistently smear-negative children and 450 asymptomatic persistently smear-positive children in Bancoumana, Mali (June 1996 to June 1998). They then followed both groups for 2 years using a cohort-based strategy. Among the 171 children with persistently negative smears, the median time for conversion to smear-positive was longer for children with sickle trait than for children without (274 vs. 108 days, P < 0.001; Cox hazard ratio = 0.56, 95% confidence interval: 0.33, 0.96; P = 0.036). Similar differences were found in the median times to reinfection after spontaneous clearance without treatment (365 days vs. 184 days; P = 0.01). Alternatively, among the 450 asymptomatic children with persistently positive smears, the median time for conversion to smear-negative (spontaneous clearance) was shorter for children with sickle trait than for children without (190 vs. 365 days; P = 0.02). These protective effects of sickle trait against asymptomatic P. falciparum infection under conditions of natural transmission were demonstrable using a cohort-based approach but not when the same data were examined using a cross-sectional approach. PMID:23035141

  10. Can Mixed Parasite Infections Thwart Targeted Malaria Elimination Program in India?

    PubMed Central

    Singh, Upasana Shyamsunder; Siwal, Nisha; Pande, Veena

    2017-01-01

    India is highly endemic to malaria with prevalence of all five species of human malaria parasites of Plasmodium genus. India is set for malaria elimination by 2030. Since cases of mixed Plasmodium species infections remain usually undetected but cause huge disease burden, in order to understand the distributional prevalence of both monospecies infections and mixed species infections in India, we collated published data on the differential infection incidences of the five different malaria parasites based on PCR diagnostic assay. About 11% of total cases were due to mixed species infection. Among several interesting observations on both single and mixed parasitic infections, incidences of Plasmodium falciparum monoinfection were found to be significantly higher than P. vivax monoinfection. Also, P. malariae seems to be emerging as a potential malaria threat in India. Putting all the facts together, it appears that the dream of achieving malaria elimination in India will not be completely successful without dealing with mixed species infection. PMID:28900620

  11. Submicroscopic and asymptomatic Plasmodium falciparum and Plasmodium vivax infections are common in western Thailand - molecular and serological evidence.

    PubMed

    Baum, Elisabeth; Sattabongkot, Jetsumon; Sirichaisinthop, Jeeraphat; Kiattibutr, Kirakorn; Davies, D Huw; Jain, Aarti; Lo, Eugenia; Lee, Ming-Chieh; Randall, Arlo Z; Molina, Douglas M; Liang, Xiaowu; Cui, Liwang; Felgner, Philip L; Yan, Guiyun

    2015-02-25

    Malaria is a public health problem in parts of Thailand, where Plasmodium falciparum and Plasmodium vivax are the main causes of infection. In the northwestern border province of Tak parasite prevalence is now estimated to be less than 1% by microscopy. Nonetheless, microscopy is insensitive at low-level parasitaemia. The objective of this study was to assess the current epidemiology of falciparum and vivax malaria in Tak using molecular methods to detect exposure to and infection with parasites; in particular, the prevalence of asymptomatic infections and infections with submicroscopic parasite levels. Three-hundred microlitres of whole blood from finger-prick were collected into capillary tubes from residents of a sentinel village and from patients at a malaria clinic. Pelleted cellular fractions were screened by quantitative PCR to determine parasite prevalence, while plasma was probed on a protein microarray displaying hundreds of P. falciparum and P. vivax proteins to obtain antibody response profiles in those individuals. Of 219 samples from the village, qPCR detected 25 (11.4%) Plasmodium sp. infections, of which 92% were asymptomatic and 100% were submicroscopic. Of 61 samples from the clinic patients, 27 (44.3%) were positive by qPCR, of which 25.9% had submicroscopic parasite levels. Cryptic mixed infections, misdiagnosed as single-species infections by microscopy, were found in 7 (25.9%) malaria patients. All sample donors, parasitaemic and non-parasitaemic alike, had serological evidence of parasite exposure, with 100% seropositivity to at least 54 antigens. Antigens significantly associated with asymptomatic infections were P. falciparum MSP2, DnaJ protein, putative E1E2 ATPase, and three others. These findings suggest that parasite prevalence is higher than currently estimated by local authorities based on the standard light microscopy. As transmission levels drop in Thailand, it may be necessary to employ higher throughput and sensitivity methods for

  12. A molecular survey of acute febrile illnesses reveals Plasmodium vivax infections in Kedougou, southeastern Senegal.

    PubMed

    Niang, Makhtar; Thiam, Laty Gaye; Sow, Abdourahmane; Loucoubar, Cheikh; Bob, Ndeye Sakha; Diop, Fode; Diouf, Babacar; Niass, Oumy; Mansourou, Annick; Varela, Marie Louise; Perraut, Ronald; Sall, Amadou A; Toure-Balde, Aissatou

    2015-07-19

    Control efforts towards malaria due to Plasmodium falciparum significantly decreased the incidence of the disease in many endemic countries including Senegal. Surprisingly, in Kedougou (southeastern Senegal) P. falciparum malaria remains highly prevalent and the relative contribution of other Plasmodium species to the global malaria burden is very poorly documented, partly due to the low sensitivity of routine diagnostic tools. Molecular methods offer better estimate of circulating Plasmodium species in a given area. A molecular survey was carried out to document circulating malaria parasites in Kedougou region. A total of 263 long-term stored sera obtained from patients presenting with acute febrile illness in Kedougou between July 2009 and July 2013 were used for malaria parasite determination. Sera were withdrawn from a collection established as part of a surveillance programme of arboviruses infections in the region. Plasmodium species were characterized by a nested PCR-based approach targeting the 18S small sub-unit ribosomal RNA genes of Plasmodium spp. Of the 263 sera screened in this study, Plasmodium genomic DNA was amplifiable by nested PCR from 62.35% (164/263) of samples. P. falciparum accounted for the majority of infections either as single in 85.97% (141/164) of Plasmodium-positive samples or mixed with Plasmodium ovale (11.58%, 19/164) or Plasmodium vivax (1.21%, 2/164). All 19 (11.58%) P. ovale-infected patients were mixed with P. falciparum, while no Plasmodium malariae was detected in this survey. Four patients (2.43%) were found to be infected by P. vivax, two of whom were mixed with P. falciparum. P. vivax infections originated from Bandafassi and Ninefesha villages and concerned patients aged 4, 9, 10, and 15 years old, respectively. DNA sequences alignment and phylogenetic analysis demonstrated that sequences from Kedougou corresponded to P. vivax, therefore confirming the presence of P. vivax infections in Senegal. The results confirm the

  13. Prevalence of Plasmodium falciparum infection in pregnant women in Gabon

    PubMed Central

    Bouyou-Akotet, Marielle K; Ionete-Collard, Denisa E; Mabika-Manfoumbi, Modeste; Kendjo, Eric; Matsiegui, Pierre-Blaise; Mavoungou, Elie; Kombila, Maryvonne

    2003-01-01

    Background In areas where malaria is endemic, pregnancy is associated with increased susceptibility to malaria. It is generally agreed that this risk ends with delivery and decreases with the number of pregnancies. Our study aimed to demonstrate relationships between malarial parasitaemia and age, gravidity and anaemia in pregnant women in Libreville, the capital city of Gabon. Methods Peripheral blood was collected from 311 primigravidae and women in their second pregnancy. Thick blood smears were checked, as were the results of haemoglobin electrophoresis. We also looked for the presence of anaemia, fever, and checked whether the volunteers had had chemoprophylaxis. The study was performed in Gabon where malaria transmission is intense and perennial. Results A total of 177 women (57%) had microscopic parasitaemia; 139 (64%)of them were primigravidae, 38 (40%) in their second pregnancy and 180 (64%) were teenagers. The parasites densities were also higher in primigravidae and teenagers. The prevalence of anaemia was 71% and was associated with microscopic Plasmodium falciparum parasitaemia: women with moderate or severe anaemia had higher parasite prevalences and densities. However, the sickle cell trait, fever and the use of chemoprophylaxis did not have a significant association with the presence of P. falciparum. Conclusions These results suggest that the prevalence of malaria and the prevalence of anaemia, whether associated with malaria or not, are higher in pregnant women in Gabon. Primigravidae and young pregnant women are the most susceptible to infection. It is, therefore, urgent to design an effective regimen of malaria prophylaxis for this high risk population. PMID:12919637

  14. Mixed species flock, nest height, and elevation partially explain avian haemoparasite prevalence in Colombia.

    PubMed

    González, Angie D; Matta, Nubia E; Ellis, Vincenzo A; Miller, Eliot T; Ricklefs, Robert E; Gutiérrez, H Rafael

    2014-01-01

    The high avian biodiversity present in the Neotropical region offers a great opportunity to explore the ecology of host-parasite relationships. We present a survey of avian haemoparasites in a megadiverse country and explore how parasite prevalences are related to physical and ecological host characteristics. Using light microscopy, we documented the presence of haemoparasites in over 2000 individuals belonging to 246 species of wild birds, from nine localities and several ecosystems of Colombia. We analysed the prevalence of six avian haemoparasite taxa in relation to elevation and the following host traits: nest height, nest type, foraging strata, primary diet, sociality, migratory behaviour, and participation in mixed species flocks. Our analyses indicate significant associations between both mixed species flocks and nest height and Haemoproteus and Leucocytozoon prevalence. The prevalence of Leucocytozoon increased with elevation, whereas the prevalence of Trypanosoma and microfilariae decreased. Plasmodium and Haemoproteus prevalence did not vary significantly with elevation; in fact, both parasites were found up to 3300 m above sea level. The distribution of parasite prevalence across the phylogeny of bird species included in this study showed little host phylogenetic signal indicating that infection rates in this system are evolutionarily labile. Vector distribution as well as the biology of transmission and the maintenance of populations of avian haemoparasites deserve more detailed study in this system.

  15. Mixed Species Flock, Nest Height, and Elevation Partially Explain Avian Haemoparasite Prevalence in Colombia

    PubMed Central

    González, Angie D.; Matta, Nubia E.; Ellis, Vincenzo A.; Miller, Eliot T.; Ricklefs, Robert E.; Gutiérrez, H. Rafael

    2014-01-01

    The high avian biodiversity present in the Neotropical region offers a great opportunity to explore the ecology of host-parasite relationships. We present a survey of avian haemoparasites in a megadiverse country and explore how parasite prevalences are related to physical and ecological host characteristics. Using light microscopy, we documented the presence of haemoparasites in over 2000 individuals belonging to 246 species of wild birds, from nine localities and several ecosystems of Colombia. We analysed the prevalence of six avian haemoparasite taxa in relation to elevation and the following host traits: nest height, nest type, foraging strata, primary diet, sociality, migratory behaviour, and participation in mixed species flocks. Our analyses indicate significant associations between both mixed species flocks and nest height and Haemoproteus and Leucocytozoon prevalence. The prevalence of Leucocytozoon increased with elevation, whereas the prevalence of Trypanosoma and microfilariae decreased. Plasmodium and Haemoproteus prevalence did not vary significantly with elevation; in fact, both parasites were found up to 3300m above sea level. The distribution of parasite prevalence across the phylogeny of bird species included in this study showed little host phylogenetic signal indicating that infection rates in this system are evolutionarily labile. Vector distribution as well as the biology of transmission and the maintenance of populations of avian haemoparasites deserve more detailed study in this system. PMID:24950223

  16. A method to preserve low parasitaemia Plasmodium-infected avian blood for host and vector infectivity assays.

    PubMed

    Carlson, Jenny S; Giannitti, Federico; Valkiūnas, Gediminas; Tell, Lisa A; Snipes, Joy; Wright, Stan; Cornel, Anthony J

    2016-03-11

    Avian malaria vector competence studies are needed to understand more succinctly complex avian parasite-vector-relations. The lack of vector competence trials may be attributed to the difficulty of obtaining gametocytes for the majority of Plasmodium species and lineages. To conduct avian malaria infectivity assays for those Plasmodium spp. and lineages that are refractory to in vitro cultivation, it is necessary to obtain and preserve for short periods sufficient viable merozoites to infect naïve donor birds to be used as gametocyte donors to infect mosquitoes. Currently, there is only one described method for long-term storage of Plasmodium spp.-infected wild avian blood and it is reliable at a parasitaemia of at least 1%. However, most naturally infected wild-caught birds have a parasitaemia of much less that 1%. To address this problem, a method for short-term storage of infected wild avian blood with low parasitaemia (even ≤ 0.0005%) has been explored and validated. To obtain viable infective merozoites, blood was collected from wild birds using a syringe containing the anticoagulant and the red blood cell preservative citrate phosphate dextrose adenine solution (CPDA). Each blood sample was stored at 4 °C for up to 48 h providing sufficient time to determine the species and parasitaemia of Plasmodium spp. in the blood by morphological examination before injecting into donor canaries. Plasmodium spp.--infected blood was inoculated intravenously into canaries and once infection was established, Culex stigmatosoma, Cx. pipiens and Cx. quinquefasciatus mosquitoes were then allowed to feed on the infected canaries to validate the efficacy of this method for mosquito vector competence assays. Storage of Plasmodium spp.--infected donor blood at 4 °C yielded viable parasites for 48 h. All five experimentally-infected canaries developed clinical signs and were infectious. Pathologic examination of three canaries that later died revealed splenic lesions typical of

  17. Resistance of infection by Plasmodium vivax to chloroquine in Bolivia.

    PubMed

    Añez, Arletta; Moscoso, Manuel; Laguna, Ángel; Garnica, Cecilia; Melgar, Viviana; Cuba, Mauren; Gutierrez, Sonia; Ascaso, Carlos

    2015-07-01

    Chloroquine (CQ) over three days plus primaquine (PQ) for seven days is the treatment of choice of infections by Plasmodium vivax in Bolivia, where 95% of the cases of malaria are attributed to this species. The aim of this study was to evaluate the therapeutic efficacy of CQ in this setting. Patients in the Amazon region of northern Bolivia, were included in the study from May to November 2011 and the therapeutic efficacy of CQ was evaluated over a 28-day follow-up period. Patients with P. vivax mono-infection received 25 mg/Kg body weight of CQ over three days. The concentrations of CQ + desethylchloroquine (DCQ) in blood were determined at days 7 and 28 of follow up; at follow-up and on the day of treatment failure was administered PQ. One hundred patients fulfilled the inclusion criteria, two were lost to follow up and another two were later excluded for protocol violation. Of the 96 patients who completed the follow up 10 showed TF; one presented continued parasitaemia until day 7 of follow up, three on day 21 and six on day 28 of follow up. The geometric mean of CQ + DCQ on day 7 was 321.7 ng/ml (range 197-535 ng/ml). In six patients with TF the CQ + DCQ concentrations in blood on the day of TF were >100 ng/ml. The rate of resistance was 6.5%. The present study demonstrates the presence of resistance to CQ in the treatment of malaria by P. vivax in the Amazon region of Bolivia. New clinical trials are needed to establish alternative treatments against these parasites in this region of South America.

  18. A natural Anopheles-associated Penicillium chrysogenum enhances mosquito susceptibility to Plasmodium infection.

    PubMed

    Angleró-Rodríguez, Yesseinia I; Blumberg, Benjamin J; Dong, Yuemei; Sandiford, Simone L; Pike, Andrew; Clayton, April M; Dimopoulos, George

    2016-09-28

    Whereas studies have extensively examined the ability of bacteria to influence Plasmodium infection in the mosquito, the tripartite interactions between non-entomopathogenic fungi, mosquitoes, and Plasmodium parasites remain largely uncharacterized. Here we report the isolation of a common mosquito-associated ascomycete fungus, Penicillium chrysogenum, from the midgut of field-caught Anopheles mosquitoes. Although the presence of Pe. chrysogenum in the Anopheles gambiae midgut does not affect mosquito survival, it renders the mosquito significantly more susceptible to Plasmodium infection through a secreted heat-stable factor. We further provide evidence that the mechanism of the fungus-mediated modulation of mosquito susceptibility to Plasmodium involves an upregulation of the insect's ornithine decarboxylase gene, which sequesters arginine for polyamine biosynthesis. Arginine plays an important role in the mosquito's anti-Plasmodium defense as a substrate of nitric oxide production, and its availability therefore has a direct impact on the mosquito's susceptibility to the parasite. While this type of immunomodulatory mechanism has already been demonstrated in other host-pathogen interaction systems, this is the first report of a mosquito-associated fungus that can suppress the mosquito's innate immune system in a way that would favor Plasmodium infection and possibly malaria transmission.

  19. A natural Anopheles-associated Penicillium chrysogenum enhances mosquito susceptibility to Plasmodium infection

    PubMed Central

    Angleró-Rodríguez, Yesseinia I.; Blumberg, Benjamin J.; Dong, Yuemei; Sandiford, Simone L.; Pike, Andrew; Clayton, April M.; Dimopoulos, George

    2016-01-01

    Whereas studies have extensively examined the ability of bacteria to influence Plasmodium infection in the mosquito, the tripartite interactions between non-entomopathogenic fungi, mosquitoes, and Plasmodium parasites remain largely uncharacterized. Here we report the isolation of a common mosquito-associated ascomycete fungus, Penicillium chrysogenum, from the midgut of field-caught Anopheles mosquitoes. Although the presence of Pe. chrysogenum in the Anopheles gambiae midgut does not affect mosquito survival, it renders the mosquito significantly more susceptible to Plasmodium infection through a secreted heat-stable factor. We further provide evidence that the mechanism of the fungus-mediated modulation of mosquito susceptibility to Plasmodium involves an upregulation of the insect’s ornithine decarboxylase gene, which sequesters arginine for polyamine biosynthesis. Arginine plays an important role in the mosquito’s anti-Plasmodium defense as a substrate of nitric oxide production, and its availability therefore has a direct impact on the mosquito’s susceptibility to the parasite. While this type of immunomodulatory mechanism has already been demonstrated in other host-pathogen interaction systems, this is the first report of a mosquito-associated fungus that can suppress the mosquito’s innate immune system in a way that would favor Plasmodium infection and possibly malaria transmission. PMID:27678168

  20. Clustered local transmission and asymptomatic Plasmodium falciparum and Plasmodium vivax malaria infections in a recently emerged, hypoendemic Peruvian Amazon community

    PubMed Central

    Branch, OraLee; Casapia, W Martin; Gamboa, Dionicia V; Hernandez, Jean N; Alava, Freddy F; Roncal, Norma; Alvarez, Eugenia; Perez, Enrique J; Gotuzzo, Eduardo

    2005-01-01

    Background There is a low incidence of malaria in Iquitos, Peru, suburbs detected by passive case-detection. This low incidence might be attributable to infections clustered in some households/regions and/or undetected asymptomatic infections. Methods Passive case-detection (PCD) during the malaria season (February-July) and an active case-detection (ACD) community-wide survey (March) surveyed 1,907 persons. Each month, April-July, 100-metre at-risk zones were defined by location of Plasmodium falciparum infections in the previous month. Longitudinal ACD and PCD (ACP+PCD) occurred within at-risk zones, where 137 houses (573 persons) were randomly selected as sentinels, each with one month of weekly active sampling. Entomological captures were conducted in the sentinel houses. Results The PCD incidence was 0.03 P. falciparum and 0.22 Plasmodium vivax infections/person/malaria-season. However, the ACD+PCD prevalence was 0.13 and 0.39, respectively. One explanation for this 4.33 and 1.77-fold increase, respectively, was infection clustering within at-risk zones and contiguous households. Clustering makes PCD, generalized to the entire population, artificially low. Another attributable-factor was that only 41% and 24% of the P. falciparum and P. vivax infections were associated with fever and 80% of the asymptomatic infections had low-density or absent parasitaemias the following week. After accounting for asymptomatic infections, a 2.6-fold increase in ACD+PCD versus PCD was attributable to clustered transmission in at-risk zones. Conclusion Even in low transmission, there are frequent highly-clustered asymptomatic infections, making PCD an inadequate measure of incidence. These findings support a strategy of concentrating ACD and insecticide campaigns in houses adjacent to houses were malaria was detected one month prior. PMID:15975146

  1. Prevalence of Plasmodium falciparum Infection in Rainy Season, Artibonite Valley, Haiti, 2006

    PubMed Central

    Keating, Joseph; Bennett, Adam; Londono, Berlin; Johnson, Dawn; Lafontant, Christina; Krogstad, Donald J.

    2007-01-01

    We conducted a population-based survey to estimate the prevalence of Plasmodium falciparum infection among persons older than 1 month in the Artibonite Valley of Haiti during the high malaria transmission season in 2006. Results from PCR for 714 persons showed a prevalence of 3.1% for P. falciparum infection. PMID:18257993

  2. Prevalence of Plasmodium falciparum infection in rainy season, Artibonite Valley, Haiti, 2006.

    PubMed

    Eisele, Thomas P; Keating, Joseph; Bennett, Adam; Londono, Berlin; Johnson, Dawn; Lafontant, Christina; Krogstad, Donald J

    2007-10-01

    We conducted a population-based survey to estimate the prevalence of Plasmodium falciparum infection among persons older than 1 month in the Artibonite Valley of Haiti during the high malaria transmission season in 2006. Results from PCR for 714 persons showed a prevalence of 3.1% for P. falciparum infection.

  3. Multigenomic Delineation of Plasmodium Species of the Laverania Subgenus Infecting Wild-Living Chimpanzees and Gorillas

    PubMed Central

    Liu, Weimin; Sundararaman, Sesh A.; Loy, Dorothy E.; Learn, Gerald H.; Li, Yingying; Plenderleith, Lindsey J.; Ndjango, Jean-Bosco N.; Speede, Sheri; Atencia, Rebeca; Cox, Debby; Shaw, George M.; Ayouba, Ahidjo; Peeters, Martine; Rayner, Julian C.; Hahn, Beatrice H.; Sharp, Paul M.

    2016-01-01

    Plasmodium falciparum, the major cause of malaria morbidity and mortality worldwide, is only distantly related to other human malaria parasites and has thus been placed in a separate subgenus, termed Laverania. Parasites morphologically similar to P. falciparum have been identified in African apes, but only one other Laverania species, Plasmodium reichenowi from chimpanzees, has been formally described. Although recent studies have pointed to the existence of additional Laverania species, their precise number and host associations remain uncertain, primarily because of limited sampling and a paucity of parasite sequences other than from mitochondrial DNA. To address this, we used limiting dilution polymerase chain reaction to amplify additional parasite sequences from a large number of chimpanzee and gorilla blood and fecal samples collected at two sanctuaries and 30 field sites across equatorial Africa. Phylogenetic analyses of more than 2,000 new sequences derived from the mitochondrial, nuclear, and apicoplast genomes revealed six divergent and well-supported clades within the Laverania parasite group. Although two of these clades exhibited deep subdivisions in phylogenies estimated from organelle gene sequences, these sublineages were geographically defined and not present in trees from four unlinked nuclear loci. This greatly expanded sequence data set thus confirms six, and not seven or more, ape Laverania species, of which P. reichenowi, Plasmodium gaboni, and Plasmodium billcollinsi only infect chimpanzees, whereas Plasmodium praefalciparum, Plasmodium adleri, and Pladmodium blacklocki only infect gorillas. The new sequence data also confirm the P. praefalciparum origin of human P. falciparum. PMID:27289102

  4. Anopheles gambiae Circumsporozoite Protein–Binding Protein Facilitates Plasmodium Infection of Mosquito Salivary Glands

    PubMed Central

    Wang, Jiuling; Zhang, Yue; Zhao, Yang O.; Li, Michelle W. M.; Zhang, Lili; Dragovic, Srdjan; Abraham, Nabil M.; Fikrig, Erol

    2013-01-01

    Malaria, a mosquito-borne disease caused by Plasmodium species, causes substantial morbidity and mortality throughout the world. Plasmodium sporozoites mature in oocysts formed in the mosquito gut wall and then invade the salivary glands, where they remain until transmitted to the vertebrate host during a mosquito bite. The Plasmodium circumsporozoite protein (CSP) binds to salivary glands and plays a role in the invasion of this organ by sporozoites. We identified an Anopheles salivary gland protein, named CSP-binding protein (CSPBP), that interacts with CSP. Downregulation of CSPBP in mosquito salivary glands inhibited invasion by Plasmodium organisms. In vivo bioassays showed that mosquitoes that were fed blood with CSPBP antibody displayed a 25% and 90% reduction in the parasite load in infected salivary glands 14 and 18 days after the blood meal, respectively. These results suggest that CSPBP is important for the infection of the mosquito salivary gland by Plasmodium organisms and that blocking CSPBP can interfere with the Plasmodium life cycle. PMID:23801601

  5. A plethora of Plasmodium species in wild apes: a source of human infection?

    PubMed Central

    Rayner, Julian C.; Liu, Weimin; Peeters, Martine; Sharp, Paul M.; Hahn, Beatrice H.

    2011-01-01

    Recent studies of captive and wild-living apes in Africa have uncovered evidence of numerous new Plasmodium species, one of which was identified as the immediate precursor of human Plasmodium falciparum. These findings raise the question whether wild apes could be a recurrent source of Plasmodium infections in humans. This question is not new, but was the subject of intense investigation by researchers in the first half of the last century. Re-examination of their work in the context of recent molecular findings provides a new framework to understand the diversity of Plasmodium species and to assess the risk of future cross-species transmissions to humans in the context of proposed malaria eradication programs. PMID:21354860

  6. Natural Plasmodium infection in monkeys in the state of Rondônia (Brazilian Western Amazon).

    PubMed

    Araújo, Maisa S; Messias, Mariluce R; Figueiró, Marivaldo R; Gil, Luiz Herman S; Probst, Christian M; Vidal, Newton M; Katsuragawa, Tony H; Krieger, Marco A; Silva, Luiz H Pereira da; Ozaki, Luiz S

    2013-06-03

    Simian malaria is still an open question concerning the species of Plasmodium parasites and species of New World monkeys susceptible to the parasites. In addition, the lingering question as to whether these animals are reservoirs for human malaria might become important especially in a scenario of eradication of the disease. To aid in the answers to these questions, monkeys were surveyed for malaria parasite natural infection in the Amazonian state of Rondônia, Brazil, a state with intense environmental alterations due to human activities, which facilitated sampling of the animals. Parasites were detected and identified in DNA from blood of monkeys, by PCR with primers for the 18S rRNA, CSP and MSP1 genes and sequencing of the amplified fragments. Multiplex PCR primers for the 18S rRNA genes were designed for the parasite species Plasmodium falciparum and Plasmodium vivax, Plasmodium malariae/Plasmodium brasilianum and Plasmodium simium. An overall infection rate of 10.9% was observed or 20 out 184 monkey specimens surveyed, mostly by P. brasilianum. However, four specimens of monkeys were found infected with P. falciparum, two of them doubly infected with P. brasilianum and P. falciparum. In addition, a species of monkey of the family Aotidae, Aotus nigriceps, is firstly reported here naturally infected with P. brasilianum. None of the monkeys surveyed was found infected with P. simium/P. vivax. The rate of natural Plasmodium infection in monkeys in the Brazilian state of Rondônia is in line with previous surveys of simian malaria in the Amazon region. The fact that a monkey species was found that had not previously been described to harbour malaria parasites indicates that the list of monkey species susceptible to Plasmodium infection is yet to be completed. Furthermore, finding monkeys in the region infected with P. falciparum clearly indicates parasite transfer from humans to the animals. Whether this parasite can be transferred back to humans and how

  7. Natural Plasmodium infection in monkeys in the state of Rondônia (Brazilian Western Amazon)

    PubMed Central

    2013-01-01

    Background Simian malaria is still an open question concerning the species of Plasmodium parasites and species of New World monkeys susceptible to the parasites. In addition, the lingering question as to whether these animals are reservoirs for human malaria might become important especially in a scenario of eradication of the disease. To aid in the answers to these questions, monkeys were surveyed for malaria parasite natural infection in the Amazonian state of Rondônia, Brazil, a state with intense environmental alterations due to human activities, which facilitated sampling of the animals. Methods Parasites were detected and identified in DNA from blood of monkeys, by PCR with primers for the 18S rRNA, CSP and MSP1 genes and sequencing of the amplified fragments. Multiplex PCR primers for the 18S rRNA genes were designed for the parasite species Plasmodium falciparum and Plasmodium vivax, Plasmodium malariae/Plasmodium brasilianum and Plasmodium simium. Results An overall infection rate of 10.9% was observed or 20 out 184 monkey specimens surveyed, mostly by P. brasilianum. However, four specimens of monkeys were found infected with P. falciparum, two of them doubly infected with P. brasilianum and P. falciparum. In addition, a species of monkey of the family Aotidae, Aotus nigriceps, is firstly reported here naturally infected with P. brasilianum. None of the monkeys surveyed was found infected with P. simium/P. vivax. Conclusion The rate of natural Plasmodium infection in monkeys in the Brazilian state of Rondônia is in line with previous surveys of simian malaria in the Amazon region. The fact that a monkey species was found that had not previously been described to harbour malaria parasites indicates that the list of monkey species susceptible to Plasmodium infection is yet to be completed. Furthermore, finding monkeys in the region infected with P. falciparum clearly indicates parasite transfer from humans to the animals. Whether this parasite can be

  8. Plasmodium falciparum and Plasmodium vivax Infections in the Peruvian Amazon: Propagation of Complex, Multiple Allele-Type Infections without Super-Infection

    PubMed Central

    Sutton, Patrick L.; Neyra, Victor; Hernandez, Jean N.; Branch, OraLee H.

    2013-01-01

    Outcrossing potential between Plasmodium parasites is defined by the population-level diversity (PLD) and complexity of infection (COI). There have been few studies of PLD and COI in low transmission regions. Since the 1995–1998 Peruvian Amazon epidemic, there has been sustained transmission with < 0.5 P. falciparum and < 1.6 P. vivax infections/person/year. Using weekly active case detection, we described PLD by heterozygosity (He) and COI using P. falciparum Pfmsp1-B2 and P. vivax Pvmsp3α. Not being homologous genes, we limited comparisons to within species. P. falciparum (N = 293) had low (He = 0.581) and P. vivax (N = 186) had high (He= 0.845) PLD. A total of 9.5% P. falciparum infections and 26.3% P. vivax infections had COI > 1. Certain allele types were in more mixed infections than expected by chance. The few appearances of new alleles could be explained by stochastic polymerase chain reaction detection or synchronization/sequestration. The results suggest propagation of mixed infections by multiple inocula, not super-infection, implying decade-long opportunity for outcrossing in these mixed infections. PMID:19996422

  9. Parasitic co-infections: does Ascaris lumbricoides protect against Plasmodium falciparum infection?

    PubMed

    Brutus, Laurent; Watier, Laurence; Briand, Valérie; Hanitrasoamampionona, Virginie; Razanatsoarilala, Hélène; Cot, Michel

    2006-08-01

    A controlled randomized trial of antihelminthic treatment was undertaken in 1996-1997 in a rural area of Madagascar where populations were simultaneously infected with Ascaris lumbricoides and Plasmodium falciparum. Levamisole was administered bimonthly to 164 subjects, randomized on a family basis, whereas 186 were controls. While levamisole proved to be highly effective in reducing Ascaris egg loads in the treated group (P < 10(-3) at all bimonthly visits), subjects more than 5 years of age, treated with levamisole had a significant increase in their P. falciparum densities compared with controls (P = 0.02), whereas there was no effect of anti-helminthic treatment on children 6 months to 4 years of age. The demonstration of a clear negative interaction between Ascaris infection and malaria parasite density has important implications. Single community therapy programs to deliver treatments against several parasitic infections could avoid an increase of malaria attacks after mass treatment of ascariasis.

  10. One Episode of Self-Resolving Plasmodium yoelii Infection Transiently Exacerbates Chronic Mycobacterium tuberculosis Infection

    PubMed Central

    Blank, Jannike; Eggers, Lars; Behrends, Jochen; Jacobs, Thomas; Schneider, Bianca E.

    2016-01-01

    Malaria and tuberculosis (Tb) are two of the main causes of death from infectious diseases globally. The pathogenic agents, Plasmodium parasites and Mycobacterium tuberculosis, are co-endemic in many regions in the world, however, compared to other co-infections like HIV/Tb or helminth/Tb, malaria/Tb has been given less attention both in clinical and immunological studies. Due to the lack of sufficient human data, the impact of malaria on Tb and vice versa is difficult to estimate but co-infections are likely to occur very frequently. Due to its immunomodulatory properties malaria might be an underestimated risk factor for latent or active Tb patients particularly in high-endemic malaria settings were people experience reinfections very frequently. In the present study, we used the non-lethal strain of Plasmodium yoelii to investigate, how one episode of self-resolving malaria impact on a chronic M. tuberculosis infection. P. yoelii co-infection resulted in exacerbation of Tb disease as demonstrated by increased pathology and cellular infiltration of the lungs which coincided with elevated levels of pro- and anti-inflammatory mediators. T cell responses were not impaired in co-infected mice but enhanced and likely contributed to increased cytokine production. We found a slight but statistically significant increase in M. tuberculosis burden in co-infected animals and increased lung CFU was positively correlated with elevated levels of TNFα but not IL-10. Infection with P. yoelii induced the recruitment of a CD11c+ population into lungs and spleens of M. tuberculosis infected mice. CD11c+ cells isolated from P. yoelii infected spleens promoted survival and growth of M. tuberculosis in vitro. 170 days after P. yoelii infection changes in immunopathology and cellular immune responses were no longer apparent while M. tuberculosis numbers were still slightly higher in lungs, but not in spleens of co-infected mice. In conclusion, one episode of P. yoelii co-infection

  11. Epidemiology of Plasmodium infections in Flores Island, Indonesia using real-time PCR.

    PubMed

    Kaisar, Maria M M; Supali, Taniawati; Wiria, Aprilianto E; Hamid, Firdaus; Wammes, Linda J; Sartono, Erliyani; Luty, Adrian J F; Brienen, Eric A T; Yazdanbakhsh, Maria; van Lieshout, Lisette; Verweij, Jaco J

    2013-05-24

    DNA-based diagnostic methods have been shown to be highly sensitive and specific for the detection of malaria. An 18S-rRNA-based, real-time polymerase chain reaction (PCR) was used to determine the prevalence and intensity of Plasmodium infections on Flores Island, Indonesia. Microscopy and real-time multiplex PCR for the detection of Plasmodium species was performed on blood samples collected in a population-based study in Nangapanda Flores Island, Indonesia. A total 1,509 blood samples were analysed. Real-time PCR revealed prevalence for Plasmodium falciparum, Plasmodium vivax, and Plasmodium malariae to be 14.5%, 13.2%, and 1.9% respectively. Sub-microscopic parasitaemia were found in more than 80% of all positive cases. The prevalence of P. falciparum and P. vivax was significantly higher in subjects younger than 20 years (p ≤ 0.01). In the present study, among non-symptomatic healthy individuals, anaemia was strongly correlated with the prevalence and load of P. falciparum infections (p ≤ 0.01; p = 0.02) and with the load of P. vivax infections (p = 0.01) as detected with real-time PCR. Subjects with AB blood group tend to have a higher risk of being infected with P. falciparum and P. vivax when compared to other blood groups. The present study has shown that real-time PCR provides more insight in the epidemiology of Plasmodium infections and can be used as a monitoring tool in the battle against malaria. The unsurpassed sensitivity of real-time PCR reveals that sub microscopic infections are common in this area, which are likely to play an important role in transmission and control. Trials number ISRCTN83830814.

  12. Comparative histopathology of mice infected with the 17XL and 17XNL strains of Plasmodium yoelii.

    PubMed

    Fu, Yong; Ding, Yan; Zhou, Tao-li; Ou, Qian-yi; Xu, Wen-yue

    2012-04-01

    Plasmodium yoelii 17XL was used to investigate the mechanism of Plasmodium falciparum-caused cerebral malaria, although its histological effect on other mouse organs is still unclear. Here, histological examination was performed on mice infected with P. yoelii 17XL; the effect of P. yoelii 17XL infection on anemia and body weight loss, as well as its lesions in the brain, liver, kidney, lung, and spleen, also was investigated. Plasmodium yoelii 17XL-infected red blood cells were sequestered in the microcirculation of the brain and in the kidney. Compared with the nonlethal P. yoelii 17XNL strain, infection by P. yoelii 17XL caused substantial pulmonary edema, severe anemia, and significant body weight loss. Although P. yoelii 17XNL and 17XL produced a similar focal necrosis in the mouse liver, infection of P. yoelii 17XL induced coalescing of red and white pulp. Mortality caused by P. yoelii 17XL may be due to cerebral malaria, as well as respiratory distress syndrome and severe anemia. Plasmodium yoelii 17XL-infected rodent malaria seems to be a useful model for investigating severe malaria caused by P. falciparum.

  13. Plasmodium Infection Promotes Genomic Instability and AID Dependent B Cell Lymphoma

    PubMed Central

    Robbiani, Davide F.; Deroubaix, Stephanie; Feldhahn, Niklas; Oliveira, Thiago Y.; Callen, Elsa; Wang, Qiao; Jankovic, Mila; Silva, Israel T.; Rommel, Philipp C.; Bosque, David; Eisenreich, Tom; Nussenzweig, André; Nussenzweig, Michel C.

    2015-01-01

    Summary Chronic infection with Plasmodium falciparum was epidemiologically associated with endemic Burkitt’s lymphoma, a mature B cell cancer characterized by chromosome translocation between the c-myc oncogene and Igh, over 50 years ago. Whether infection promotes B cell lymphoma, and if so by what mechanism remains unknown. To investigate the relationship between parasitic disease and lymphomagenesis we used Plasmodium chabaudi (Pc) to produce chronic malaria infection in mice. Pc induces prolonged expansion of germinal centers (GCs), unique compartments where B cells undergo rapid clonal expansion and express activation-induced cytidine deaminase (AID), a DNA mutator. GC B cells elicited during Pc infection suffer widespread DNA damage leading to chromosome translocations. Although infection does not change the overall rate, it modifies lymphomagenesis to favor mature B cell lymphomas that are AID dependent and show chromosome translocations. Thus, malaria infection favors mature B cell cancers by eliciting protracted AID expression in GC B cells. PMID:26276629

  14. Antibody-independent mechanisms regulate the establishment of chronic Plasmodium infection

    PubMed Central

    Lin, Jingwen; Cunningham, Deirdre; Tumwine, Irene; Kushinga, Garikai; McLaughlin, Sarah; Spence, Philip; Böhme, Ulrike; Sanders, Mandy; Conteh, Solomon; Bushell, Ellen; Metcalf, Tom; Billker, Oliver; Duffy, Patrick E.; Newbold, Chris; Berriman, Matthew; Langhorne, Jean

    2017-01-01

    Malaria is caused by parasites of the genus Plasmodium. All human-infecting Plasmodium species can establish long-lasting chronic infections1–5, creating an infectious reservoir to sustain transmission1,6. It is widely accepted that maintenance of chronic infection involves evasion of adaptive immunity by antigenic variation7. However, genes involved in this process have been identified in only two of five human-infecting species: P. falciparum and P. knowlesi. Furthermore, little is understood about the early events in establishment of chronic infection in these species. Using a rodent model we demonstrate that only a minority of parasites from among the infecting population, expressing one of several clusters of virulence-associated pir genes, establishes a chronic infection. This process occurs in different species of parasite and in different hosts. Establishment of chronicity is independent of adaptive immunity and therefore different from the mechanism proposed for maintainance of chronic P. falciparum infections7–9. Furthermore, we show that the proportions of parasites expressing different types of pir genes regulate the time taken to establish a chronic infection. Since pir genes are common to most, if not all, species of Plasmodium10, this process may be a common way of regulating the establishment of chronic infections. PMID:28165471

  15. Symptoms and Immune Markers in Plasmodium/Dengue Virus Co-infection Compared with Mono-infection with Either in Peru

    PubMed Central

    Halsey, Eric S.; Baldeviano, G. Christian; Edgel, Kimberly A.; Vilcarromero, Stalin; Sihuincha, Moises; Lescano, Andres G.

    2016-01-01

    Background Malaria and dengue are two of the most common vector-borne diseases in the world, but co-infection is rarely described, and immunologic comparisons of co-infection with mono-infection are lacking. Methodology and Principal Findings We collected symptom histories and blood specimens from subjects in a febrile illness surveillance study conducted in Iquitos and Puerto Maldonado, Peru, between 2002–2011. Nineteen symptoms and 18 immune markers at presentation were compared among those with co-infection with Plasmodium/dengue virus (DENV), Plasmodium mono-infection, and DENV mono-infection. Seventeen subjects were identified as having Plasmodium/DENV co-infection and were retrospectively matched with 51 DENV mono-infected and 44 Plasmodium mono-infected subjects. Those with Plasmodium mono-infection had higher levels of IL-4, IL-6, IL-10, IL-12, IL-13, IL-17A, IFN-γ, and MIP1-α/CCL3 compared with DENV mono-infection or co-infection; those with Plasmodium mono-infection had more cough than those with DENV mono-infection. Subjects with DENV mono-infection had higher levels of TGF-β1 and more myalgia than those with Plasmodium mono-infection. No symptom was more common and no immune marker level was higher in the co-infected group, which had similar findings to the DENV mono-infected subjects. Conclusions/Significance Compared with mono-infection with either pathogen, Plasmodium/DENV co-infection was not associated with worse disease and resembled DENV mono-infection in both symptom frequency and immune marker level. PMID:27128316

  16. First case of Plasmodium knowlesi infection in a Japanese traveller returning from Malaysia.

    PubMed

    Tanizaki, Ryutaro; Ujiie, Mugen; Kato, Yasuyuki; Iwagami, Moritoshi; Hashimoto, Aki; Kutsuna, Satoshi; Takeshita, Nozomi; Hayakawa, Kyoko; Kanagawa, Shuzo; Kano, Shigeyuki; Ohmagari, Norio

    2013-04-15

    This is the first case of Plasmodium knowlesi infection in a Japanese traveller returning from Malaysia. In September 2012, a previously healthy 35-year-old Japanese man presented to National Center for Global Health and Medicine in Tokyo with a two-day history of daily fever, mild headaches and mild arthralgia. Malaria parasites were found in the Giemsa-stained thin blood smear, which showed band forms similar to Plasmodium malariae. Although a nested PCR showed the amplification of the primer of Plasmodium vivax and Plasmodium knowlesi, he was finally diagnosed with P. knowlesi mono-infection by DNA sequencing. He was treated with mefloquine, and recovered without any complications. DNA sequencing of the PCR products is indispensable to confirm P. knowlesi infection, however there is limited access to DNA sequencing procedures in endemic areas. The extent of P. knowlesi transmission in Asia has not been clearly defined. There is limited availability of diagnostic tests and routine surveillance system for reporting an accurate diagnosis in the Asian endemic regions. Thus, reporting accurately diagnosed cases of P. knowlesi infection in travellers would be important for assessing the true nature of this emerging human infection.

  17. Detection of persistent Plasmodium spp. infections in Ugandan children after artemether-lumefantrine treatment.

    PubMed

    Betson, Martha; Sousa-Figueiredo, José C; Atuhaire, Aaron; Arinaitwe, Moses; Adriko, Moses; Mwesigwa, Gerald; Nabonge, Juma; Kabatereine, Narcis B; Sutherland, Colin J; Stothard, J Russell

    2014-12-01

    During a longitudinal study investigating the dynamics of malaria in Ugandan lakeshore communities, a consistently high malaria prevalence was observed in young children despite regular treatment. To explore the short-term performance of artemether-lumefantrine (AL), a pilot investigation into parasite carriage after treatment(s) was conducted in Bukoba village. A total of 163 children (aged 2-7 years) with a positive blood film and rapid antigen test were treated with AL; only 8.7% of these had elevated axillary temperatures. On day 7 and then on day 17, 40 children (26.3%) and 33 (22.3%) were positive by microscopy, respectively. Real-time PCR analysis demonstrated that multi-species Plasmodium infections were common at baseline, with 41.1% of children positive for Plasmodium falciparum/Plasmodium malariae, 9.2% for P. falciparum/ Plasmodium ovale spp. and 8.0% for all three species. Moreover, on day 17, 39.9% of children infected with falciparum malaria at baseline were again positive for the same species, and 9.2% of those infected with P. malariae at baseline were positive for P. malariae. Here, chronic multi-species malaria infections persisted in children after AL treatment(s). Better point-of-care diagnostics for non-falciparum infections are needed, as well as further investigation of AL performance in asymptomatic individuals.

  18. IL-6 promotes CD4(+) T-cell and B-cell activation during Plasmodium infection.

    PubMed

    Sebina, I; Fogg, L G; James, K R; Soon, M S F; Akter, J; Thomas, B S; Hill, G R; Engwerda, C R; Haque, A

    2017-10-01

    Humoral immunity develops in the spleen during blood-stage Plasmodium infection. This elicits parasite-specific IgM and IgG, which control parasites and protect against malaria. Studies in mice have elucidated cells and molecules driving humoral immunity to Plasmodium, including CD4(+) T cells, B cells, interleukin (IL)-21 and ICOS. IL-6, a cytokine readily detected in Plasmodium-infected mice and humans, is recognized in other systems as a driver of humoral immunity. Here, we examined the effect of infection-induced IL-6 on humoral immunity to Plasmodium. Using P. chabaudi chabaudi AS (PcAS) infection of wild-type and IL-6(-/-) mice, we found that IL-6 helped to control parasites during primary infection. IL-6 promoted early production of parasite-specific IgM but not IgG. Notably, splenic CD138(+) plasmablast development was more dependent on IL-6 than germinal centre (GC) B-cell differentiation. IL-6 also promoted ICOS expression by CD4(+) T cells, as well as their localization close to splenic B cells, but was not required for early Tfh-cell development. Finally, IL-6 promoted parasite control, IgM and IgG production, GC B-cell development and ICOS expression by Tfh cells in a second model, Py17XNL infection. IL-6 promotes CD4(+) T-cell activation and B-cell responses during blood-stage Plasmodium infection, which encourages parasite-specific antibody production. © 2017 John Wiley & Sons Ltd.

  19. Host-cell sensors for Plasmodium activate innate immunity against liver-stage infection.

    PubMed

    Liehl, Peter; Zuzarte-Luís, Vanessa; Chan, Jennie; Zillinger, Thomas; Baptista, Fernanda; Carapau, Daniel; Konert, Madlen; Hanson, Kirsten K; Carret, Céline; Lassnig, Caroline; Müller, Mathias; Kalinke, Ulrich; Saeed, Mohsan; Chora, Angelo Ferreira; Golenbock, Douglas T; Strobl, Birgit; Prudêncio, Miguel; Coelho, Luis P; Kappe, Stefan H; Superti-Furga, Giulio; Pichlmair, Andreas; Vigário, Ana M; Rice, Charles M; Fitzgerald, Katherine A; Barchet, Winfried; Mota, Maria M

    2014-01-01

    Before they infect red blood cells and cause malaria, Plasmodium parasites undergo an obligate and clinically silent expansion phase in the liver that is supposedly undetected by the host. Here, we demonstrate the engagement of a type I interferon (IFN) response during Plasmodium replication in the liver. We identified Plasmodium RNA as a previously unrecognized pathogen-associated molecular pattern (PAMP) capable of activating a type I IFN response via the cytosolic pattern recognition receptor Mda5. This response, initiated by liver-resident cells through the adaptor molecule for cytosolic RNA sensors, Mavs, and the transcription factors Irf3 and Irf7, is propagated by hepatocytes in an interferon-α/β receptor-dependent manner. This signaling pathway is critical for immune cell-mediated host resistance to liver-stage Plasmodium infection, which we find can be primed with other PAMPs, including hepatitis C virus RNA. Together, our results show that the liver has sensor mechanisms for Plasmodium that mediate a functional antiparasite response driven by type I IFN.

  20. Detection of Mixed Infections with Plasmodium spp. by PCR, India, 2014

    PubMed Central

    Krishna, Sri; Bharti, Praveen K.; Chandel, Himashu S.; Ahmad, Amreen; Kumar, Rajesh; Singh, Puspendra P.; Singh, Mrigendra P.

    2015-01-01

    In 8 malaria-endemic states in India, mixed Plasmodium spp. infections were detected by PCR in 17.4% (265/1,521) of blood samples that microscopy had shown to contain only P. falciparum. The quality of microscopy must be improved because use of PCR for detection of malaria parasites is limited in rural areas. PMID:26401635

  1. Detection of Mixed Infections with Plasmodium spp. by PCR, India, 2014.

    PubMed

    Krishna, Sri; Bharti, Praveen K; Chandel, Himashu S; Ahmad, Amreen; Kumar, Rajesh; Singh, Puspendra P; Singh, Mrigendra P; Singh, Neeru

    2015-10-01

    In 8 malaria-endemic states in India, mixed Plasmodium spp. infections were detected by PCR in 17.4% (265/1,521) of blood samples that microscopy had shown to contain only P. falciparum. The quality of microscopy must be improved because use of PCR for detection of malaria parasites is limited in rural areas.

  2. Infection and Co-infection with Helminths and Plasmodium among School Children in Côte d’Ivoire: Results from a National Cross-Sectional Survey

    PubMed Central

    Yapi, Richard B.; Hürlimann, Eveline; Houngbedji, Clarisse A.; Ndri, Prisca B.; Silué, Kigbafori D.; Soro, Gotianwa; Kouamé, Ferdinand N.; Vounatsou, Penelope; Fürst, Thomas; N’Goran, Eliézer K.; Utzinger, Jürg; Raso, Giovanna

    2014-01-01

    Background Helminth infection and malaria remain major causes of ill-health in the tropics and subtropics. There are several shared risk factors (e.g., poverty), and hence, helminth infection and malaria overlap geographically and temporally. However, the extent and consequences of helminth-Plasmodium co-infection at different spatial scales are poorly understood. Methodology This study was conducted in 92 schools across Côte d’Ivoire during the dry season, from November 2011 to February 2012. School children provided blood samples for detection of Plasmodium infection, stool samples for diagnosis of soil-transmitted helminth (STH) and Schistosoma mansoni infections, and urine samples for appraisal of Schistosoma haematobium infection. A questionnaire was administered to obtain demographic, socioeconomic, and behavioral data. Multinomial regression models were utilized to determine risk factors for STH-Plasmodium and Schistosoma-Plasmodium co-infection. Principal Findings Complete parasitological and questionnaire data were available for 5,104 children aged 5-16 years. 26.2% of the children were infected with any helminth species, whilst the prevalence of Plasmodium infection was 63.3%. STH-Plasmodium co-infection was detected in 13.5% and Schistosoma-Plasmodium in 5.6% of the children. Multinomial regression analysis revealed that boys, children aged 10 years and above, and activities involving close contact to water were significantly and positively associated with STH-Plasmodium co-infection. Boys, wells as source of drinking water, and water contact were significantly and positively associated with Schistosoma-Plasmodium co-infection. Access to latrines, deworming, higher socioeconomic status, and living in urban settings were negatively associated with STH-Plasmodium co-infection; whilst use of deworming drugs and access to modern latrines were negatively associated with Schistosoma-Plasmodium co-infection. Conclusions/Significance More than 60% of the

  3. A sensitive, specific and reproducible real-time polymerase chain reaction method for detection of Plasmodium vivax and Plasmodium falciparum infection in field-collected anophelines.

    PubMed

    Bickersmith, Sara A; Lainhart, William; Moreno, Marta; Chu, Virginia M; Vinetz, Joseph M; Conn, Jan E

    2015-06-01

    We describe a simple method for detection of Plasmodium vivax and Plasmodium falciparum infection in anophelines using a triplex TaqMan real-time polymerase chain reaction (PCR) assay (18S rRNA). We tested the assay on Anopheles darlingi and Anopheles stephensi colony mosquitoes fed with Plasmodium-infected blood meals and in duplicate on field collected An. darlingi. We compared the real-time PCR results of colony-infected and field collected An. darlingi, separately, to a conventional PCR method. We determined that a cytochrome b-PCR method was only 3.33% as sensitive and 93.38% as specific as our real-time PCR assay with field-collected samples. We demonstrate that this assay is sensitive, specific and reproducible.

  4. The effect of Plasmodium gallinaceum on a challenge infection with Ascaridia galli in chickens.

    PubMed

    Juhl, J; Permin, A

    2002-04-19

    The effect of a primary infection with the haemoparasite Plasmodium gallinaceum on the establishment of a challenge infection with the nematode Ascaridia galli in chickens was studied. Four groups were infected as follows. Group 1: inoculated intravenously with 10(6) P. gallinaceum-infected erythrocytes on day 0; group 2: orally infected with 500 embryonated A. galli eggs on day 10; group 3: infected with P. gallinaceum on day 0 and A. galli on day 10; and group 3: non-infected control birds. The results of this investigation demonstrates that a primary infection with P. gallinaceum in chickens alters the course of a subsequent infection with A. galli. Thus, an antagonistic effect was seen in which the malaria infection caused a significant reduction on the establishment of the nematode in concurrently infected animals.

  5. Purification Methodology for Viable and Infective Plasmodium vivax Gametocytes That Is Compatible with Transmission-Blocking Assays

    PubMed Central

    Vera, Omaira; Brelas de Brito, Paula; Albrecht, Letusa; Martins-Campos, Keillen Monick; Pimenta, Paulo F. P.; Monteiro, Wuelton M.; Lacerda, Marcus V. G.

    2015-01-01

    Significant progress toward the control of malaria has been achieved, especially regarding Plasmodium falciparum infections. However, the unique biology of Plasmodium vivax hampers current control strategies. The early appearance of P. vivax gametocytes in the peripheral blood and the impossibility of culturing this parasite are major drawbacks. Using blood samples from 40 P. vivax-infected patients, we describe here a methodology to purify viable gametocytes and further infect anophelines. This method opens new avenues to validate transmission-blocking strategies. PMID:26239989

  6. Biofilm extracellular DNA enhances mixed species biofilms of Staphylococcus epidermidis and Candida albicans

    PubMed Central

    2013-01-01

    Background Polymicrobial infections are responsible for significant mortality and morbidity in adults and children. Staphylococcus epidermidis and Candida albicans are the most frequent combination of organisms isolated from polymicrobial infections. Vascular indwelling catheters are sites for mixed species biofilm formation and pose a significant risk for polymicrobial infections. We hypothesized that enhancement of biofilms in a mixed species environment increases patient mortality and morbidity. Results Mixed species biofilms of S. epidermidis and C. albicans were evaluated in vitro and in a subcutaneous catheter infection model in vivo. Mixed species biofilms were enhanced compared to single species biofilms of either S. epidermidis or C. albicans. A mixed species environment increased catheter infection and increased dissemination of S. epidermidis in mice. Microarrays were used to explore differential gene expression of S. epidermidis in the mixed species biofilms. In mixed species biofilms, compared to single species S. epidermidis biofilms, 2.7% of S. epidermidis genes were upregulated and 6% were down regulated. Staphylococcal autolysis repressors lrgA and lrgB were down regulated 36-fold and 27-fold respectively. The role of biofilm extracellular DNA was investigated by quantitation and by evaluating the effects of DNAse in a concentration and time dependent manner. S. epidermidis specific eDNA was increased in mixed species biofilms and further confirmed by degradation with DNAse. Conclusions Mixed-species biofilms are enhanced and associated with increased S. epidermidis-specific eDNA in vitro and greater systemic dissemination of S. epidermidis in vivo. Down regulation of the lrg operon, a repressor of autolysis, associated with increased eDNA suggests a possible role for bacterial autolysis in mixed species biofilms. Enhancement and systemic dissemination of S. epidermidis may explain adverse outcomes after clinical polymicrobial infections of S

  7. Biofilm extracellular DNA enhances mixed species biofilms of Staphylococcus epidermidis and Candida albicans.

    PubMed

    Pammi, Mohan; Liang, Rong; Hicks, John; Mistretta, Toni-Ann; Versalovic, James

    2013-11-14

    Polymicrobial infections are responsible for significant mortality and morbidity in adults and children. Staphylococcus epidermidis and Candida albicans are the most frequent combination of organisms isolated from polymicrobial infections. Vascular indwelling catheters are sites for mixed species biofilm formation and pose a significant risk for polymicrobial infections. We hypothesized that enhancement of biofilms in a mixed species environment increases patient mortality and morbidity. Mixed species biofilms of S. epidermidis and C. albicans were evaluated in vitro and in a subcutaneous catheter infection model in vivo. Mixed species biofilms were enhanced compared to single species biofilms of either S. epidermidis or C. albicans. A mixed species environment increased catheter infection and increased dissemination of S. epidermidis in mice. Microarrays were used to explore differential gene expression of S. epidermidis in the mixed species biofilms. In mixed species biofilms, compared to single species S. epidermidis biofilms, 2.7% of S. epidermidis genes were upregulated and 6% were down regulated. Staphylococcal autolysis repressors lrgA and lrgB were down regulated 36-fold and 27-fold respectively. The role of biofilm extracellular DNA was investigated by quantitation and by evaluating the effects of DNAse in a concentration and time dependent manner. S. epidermidis specific eDNA was increased in mixed species biofilms and further confirmed by degradation with DNAse. Mixed-species biofilms are enhanced and associated with increased S. epidermidis-specific eDNA in vitro and greater systemic dissemination of S. epidermidis in vivo. Down regulation of the lrg operon, a repressor of autolysis, associated with increased eDNA suggests a possible role for bacterial autolysis in mixed species biofilms. Enhancement and systemic dissemination of S. epidermidis may explain adverse outcomes after clinical polymicrobial infections of S. epidermidis and C. albicans.

  8. Contribution of Plasmodium knowlesi to Multispecies Human Malaria Infections in North Sumatera, Indonesia.

    PubMed

    Lubis, Inke N D; Wijaya, Hendri; Lubis, Munar; Lubis, Chairuddin P; Divis, Paul C S; Beshir, Khalid B; Sutherland, Colin J

    2017-04-01

    As Indonesia works toward the goal of malaria elimination, information is lacking on malaria epidemiology from some western provinces. As a basis for studies of antimalarial efficacy, we set out to survey parasite carriage in 3 communities in North Sumatera Province. A combination of active and passive detection of infection was carried out among communities in Batubara, Langkat, and South Nias regencies. Finger-prick blood samples from consenting individuals of all ages provided blood films for microscopic examination and blood spots on filter paper. Plasmodium species were identified using nested polymerase chain reaction (PCR) of ribosomal RNA genes and a novel assay that amplifies a conserved sequence specific for the sicavar gene family of Plasmodium knowlesi. Of 3731 participants, 614 (16.5%) were positive for malaria parasites by microscopy. PCR detected parasite DNA in samples from 1169 individuals (31.3%). In total, 377 participants (11.8%) harbored P. knowlesi. Also present were Plasmodium vivax (14.3%), Plasmodium falciparum (10.5%) and Plasmodium malariae (3.4%). Amplification of sicavar is a specific and sensitive test for the presence of P. knowlesi DNA in humans. Subpatent and asymptomatic multispecies parasitemia is relatively common in North Sumatera, so PCR-based surveillance is required to support control and elimination activities.

  9. Detection of Plasmodium falciparum-infected red blood cells by optical stretching

    NASA Astrophysics Data System (ADS)

    Mauritz, Jakob M. A.; Tiffert, Teresa; Seear, Rachel; Lautenschläger, Franziska; Esposito, Alessandro; Lew, Virgilio L.; Guck, Jochen; Kaminski, Clemens F.

    2010-05-01

    We present the application of a microfluidic optical cell stretcher to measure the elasticity of malaria-infected red blood cells. The measurements confirm an increase in host cell rigidity during the maturation of the parasite Plasmodium falciparum. The device combines the selectivity and sensitivity of single-cell elasticity measurements with a throughput that is higher than conventional single-cell techniques. The method has potential to detect early stages of infection with excellent sensitivity and high speed.

  10. Multigenomic Delineation of Plasmodium Species of the Laverania Subgenus Infecting Wild-Living Chimpanzees and Gorillas.

    PubMed

    Liu, Weimin; Sundararaman, Sesh A; Loy, Dorothy E; Learn, Gerald H; Li, Yingying; Plenderleith, Lindsey J; Ndjango, Jean-Bosco N; Speede, Sheri; Atencia, Rebeca; Cox, Debby; Shaw, George M; Ayouba, Ahidjo; Peeters, Martine; Rayner, Julian C; Hahn, Beatrice H; Sharp, Paul M

    2016-07-02

    Plasmodium falciparum, the major cause of malaria morbidity and mortality worldwide, is only distantly related to other human malaria parasites and has thus been placed in a separate subgenus, termed Laverania Parasites morphologically similar to P. falciparum have been identified in African apes, but only one other Laverania species, Plasmodium reichenowi from chimpanzees, has been formally described. Although recent studies have pointed to the existence of additional Laverania species, their precise number and host associations remain uncertain, primarily because of limited sampling and a paucity of parasite sequences other than from mitochondrial DNA. To address this, we used limiting dilution polymerase chain reaction to amplify additional parasite sequences from a large number of chimpanzee and gorilla blood and fecal samples collected at two sanctuaries and 30 field sites across equatorial Africa. Phylogenetic analyses of more than 2,000 new sequences derived from the mitochondrial, nuclear, and apicoplast genomes revealed six divergent and well-supported clades within the Laverania parasite group. Although two of these clades exhibited deep subdivisions in phylogenies estimated from organelle gene sequences, these sublineages were geographically defined and not present in trees from four unlinked nuclear loci. This greatly expanded sequence data set thus confirms six, and not seven or more, ape Laverania species, of which P. reichenowi, Plasmodium gaboni, and Plasmodium billcollinsi only infect chimpanzees, whereas Plasmodium praefalciparum, Plasmodium adleri, and Pladmodium blacklocki only infect gorillas. The new sequence data also confirm the P. praefalciparum origin of human P. falciparum. © The Author(s) 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  11. Interactive cost of Plasmodium infection and insecticide resistance in the malaria vector Anopheles gambiae.

    PubMed

    Alout, Haoues; Dabiré, Roch K; Djogbénou, Luc S; Abate, Luc; Corbel, Vincent; Chandre, Fabrice; Cohuet, Anna

    2016-07-19

    Insecticide resistance raises concerns for the control of vector-borne diseases. However, its impact on parasite transmission could be diverse when considering the ecological interactions between vector and parasite. Thus we investigated the fitness cost associated with insecticide resistance and Plasmodium falciparum infection as well as their interactive cost on Anopheles gambiae survival and fecundity. In absence of infection, we observed a cost on fecundity associated with insecticide resistance. However, survival was higher for mosquito bearing the kdr mutation and equal for those with the ace-1(R) mutation compared to their insecticide susceptible counterparts. Interestingly, Plasmodium infection reduced survival only in the insecticide resistant strains but not in the susceptible one and infection was associated with an increase in fecundity independently of the strain considered. This study provides evidence for a survival cost associated with infection by Plasmodium parasite only in mosquito selected for insecticide resistance. This suggests that the selection of insecticide resistance mutation may have disturbed the interaction between parasites and vectors, resulting in increased cost of infection. Considering the fitness cost as well as other ecological aspects of this natural mosquito-parasite combination is important to predict the epidemiological impact of insecticide resistance.

  12. Interactive cost of Plasmodium infection and insecticide resistance in the malaria vector Anopheles gambiae

    PubMed Central

    Alout, Haoues; Dabiré, Roch K.; Djogbénou, Luc S.; Abate, Luc; Corbel, Vincent; Chandre, Fabrice; Cohuet, Anna

    2016-01-01

    Insecticide resistance raises concerns for the control of vector-borne diseases. However, its impact on parasite transmission could be diverse when considering the ecological interactions between vector and parasite. Thus we investigated the fitness cost associated with insecticide resistance and Plasmodium falciparum infection as well as their interactive cost on Anopheles gambiae survival and fecundity. In absence of infection, we observed a cost on fecundity associated with insecticide resistance. However, survival was higher for mosquito bearing the kdr mutation and equal for those with the ace-1R mutation compared to their insecticide susceptible counterparts. Interestingly, Plasmodium infection reduced survival only in the insecticide resistant strains but not in the susceptible one and infection was associated with an increase in fecundity independently of the strain considered. This study provides evidence for a survival cost associated with infection by Plasmodium parasite only in mosquito selected for insecticide resistance. This suggests that the selection of insecticide resistance mutation may have disturbed the interaction between parasites and vectors, resulting in increased cost of infection. Considering the fitness cost as well as other ecological aspects of this natural mosquito-parasite combination is important to predict the epidemiological impact of insecticide resistance. PMID:27432257

  13. In vitro alterations do not reflect a requirement for host cell cycle progression during Plasmodium liver stage infection.

    PubMed

    Hanson, Kirsten K; March, Sandra; Ng, Shengyong; Bhatia, Sangeeta N; Mota, Maria M

    2015-01-01

    Prior to invading nonreplicative erythrocytes, Plasmodium parasites undergo their first obligate step in the mammalian host inside hepatocytes, where each sporozoite replicates to generate thousands of merozoites. While normally quiescent, hepatocytes retain proliferative capacity and can readily reenter the cell cycle in response to diverse stimuli. Many intracellular pathogens, including protozoan parasites, manipulate the cell cycle progression of their host cells for their own benefit, but it is not known whether the hepatocyte cell cycle plays a role during Plasmodium liver stage infection. Here, we show that Plasmodium parasites can be observed in mitotic hepatoma cells throughout liver stage development, where they initially reduce the likelihood of mitosis and ultimately lead to significant acquisition of a binucleate phenotype. However, hepatoma cells pharmacologically arrested in S phase still support robust and complete Plasmodium liver stage development, which thus does not require cell cycle progression in the infected cell in vitro. Furthermore, murine hepatocytes remain quiescent throughout in vivo infection with either Plasmodium berghei or Plasmodium yoelii, as do Plasmodium falciparum-infected primary human hepatocytes, demonstrating that the rapid and prodigious growth of liver stage parasites is accomplished independent of host hepatocyte cell cycle progression during natural infection.

  14. HGF Secreted by Activated Kupffer Cells Induces Apoptosis of Plasmodium-Infected Hepatocytes

    PubMed Central

    Gonçalves, Lígia Antunes; Rodo, Joana; Rodrigues-Duarte, Lurdes; de Moraes, Luciana Vieira; Penha-Gonçalves, Carlos

    2017-01-01

    Malaria liver stage infection is an obligatory parasite development step and represents a population bottleneck in Plasmodium infections, providing an advantageous target for blocking parasite cycle progression. Parasite development inside hepatocytes implies a gross cellular insult evoking innate host responses to counteract intra-hepatocytic infection. Using primary hepatocyte cultures, we investigated the role of Kupffer cell-derived hepatocyte growth factor (HGF) in malaria liver stage infection. We found that Kupffer cells from Plasmodium-infected livers produced high levels of HGF, which trigger apoptosis of infected hepatocytes through a mitochondrial-independent apoptosis pathway. HGF action in infected hepatocyte primary cultures results in a potent reduction of parasite yield by specifically sensitizing hepatocytes carrying established parasite exo-erythrocytic forms to undergo apoptosis. This apoptosis mechanism is distinct from cell death that is spontaneously induced in infected cultures and is governed by Fas signaling modulation through a mitochondrial-dependent apoptosis pathway. This work indicates that HGF and Fas signaling pathways are part of an orchestrated host apoptosis response that occurs during malaria liver stage infection, decreasing the success of infection of individual hepatocytes. Our results raise the hypothesis that paracrine signals derived from Kupffer cell activation are implicated in directing death of hepatocytes infected with the malaria parasite. PMID:28220125

  15. Characterization of blood dendritic and regulatory T cells in asymptomatic adults with sub-microscopic Plasmodium falciparum or Plasmodium vivax infection.

    PubMed

    Kho, Steven; Marfurt, Jutta; Handayuni, Irene; Pava, Zuleima; Noviyanti, Rintis; Kusuma, Andreas; Piera, Kim A; Burdam, Faustina H; Kenangalem, Enny; Lampah, Daniel A; Engwerda, Christian R; Poespoprodjo, Jeanne R; Price, Ric N; Anstey, Nicholas M; Minigo, Gabriela; Woodberry, Tonia

    2016-06-21

    Plasmodium falciparum and Plasmodium vivax infections compromise dendritic cell (DC) function and expand regulatory T (Treg) cells in both clinical disease (malaria) and experimental human sub-microscopic infection. Conversely, in asymptomatic microscopy-positive (patent) P. falciparum or P. vivax infection in endemic areas, blood DC increase or retain HLA-DR expression and Treg cells exhibit reduced activation, suggesting that DC and Treg cells contribute to the control of patent asymptomatic infection. The effect of sub-microscopic (sub-patent) asymptomatic Plasmodium infection on DC and Treg cells in malaria-endemic area residents remains unclear. In a cross-sectional household survey conducted in Papua, Indonesia, 162 asymptomatic adults were prospectively evaluated for DC and Treg cells using field-based flow cytometry. Of these, 161 individuals (99 %) were assessed retrospectively by polymerase chain reaction (PCR), 19 of whom had sub-microscopic infection with P. falciparum and 15 with sub-microscopic P. vivax infection. Flow cytometric data were re-analysed after re-grouping asymptomatic individuals according to PCR results into negative controls, sub-microscopic and microscopic parasitaemia to examine DC and Treg cell phenotype in sub-microscopic infection. Asymptomatic adults with sub-microscopic P. falciparum or P. vivax infection had DC HLA-DR expression and Treg cell activation comparable to PCR-negative controls. Sub-microscopic P. falciparum infection was associated with lower peripheral CD4(+) T cells and lymphocytes, however sub-microscopic Plasmodium infection had no apparent effect on DC sub-set number or Treg cell frequency. In contrast to the impairment of DC maturation/function and the activation of Treg cells seen with sub-microscopic parasitaemia in primary experimental human Plasmodium infection, no phenotypic evidence of dysregulation of DC and Treg cells was observed in asymptomatic sub-microscopic Plasmodium infection in Indonesian

  16. Avian Plasmodium infection in field-collected mosquitoes during 2012-2013 in Tarlac, Philippines.

    PubMed

    Chen, Tien-Huang; Aure, Wilfredo E; Cruz, Estrella Irlandez; Malbas, Fedelino F; Teng, Hwa-Jen; Lu, Liang-Chen; Kim, Kyeong Soon; Tsuda, Yoshio; Shu, Pei-Yun

    2015-12-01

    Global warming threatens to increase the spread and prevalence of mosquito-transmitted diseases. Certain pathogens may be carried by migratory birds and transmitted to local mosquito populations. Mosquitoes were collected in the northern Philippines during bird migration seasons to detect avian malaria parasites as well as for the identification of potential vector species and the estimation of infections among local mosquito populations. We used the nested PCR to detect the avian malaria species. Culex vishnui (47.6%) was the most abundant species collected and Cx. tritaeniorhynchus (13.8%) was the second most abundant. Avian Plasmodium parasites were found in eight mosquito species, for which the infection rates were between 0.5% and 6.2%. The six Plasmodium genetic lineages found in this study included P. juxtanucleare -GALLUS02, Tacy7 (Donana04), CXBIT01, Plasmodium species LIN2 New Zealand, and two unclassified lineages. The potential mosquito vectors for avian Plasmodium parasites in the Philippines were Cq. crassipes, Cx. fuscocephala, Cx. quinquefasciatus, Cx. sitiens, Cx. vishnui, and Ma. Uniformis; two major genetic lineages, P. juxtanucleare and Tacy7, were identified.

  17. Phylogenetic analysis of simian Plasmodium spp. infecting Anopheles balabacensis Baisas in Sabah, Malaysia.

    PubMed

    Chua, Tock H; Manin, Benny O; Daim, Sylvia; Vythilingam, Indra; Drakeley, Chris

    2017-10-02

    Anopheles balabacensis of the Leucospyrus group has been confirmed as the primary knowlesi malaria vector in Sabah, Malaysian Borneo for some time now. Presently, knowlesi malaria is the only zoonotic simian malaria in Malaysia with a high prevalence recorded in the states of Sabah and Sarawak. Anopheles spp. were sampled using human landing catch (HLC) method at Paradason village in Kudat district of Sabah. The collected Anopheles were identified morphologically and then subjected to total DNA extraction and polymerase chain reaction (PCR) to detect Plasmodium parasites in the mosquitoes. Identification of Plasmodium spp. was confirmed by sequencing the SSU rRNA gene with species specific primers. MEGA4 software was then used to analyse the SSU rRNA sequences and bulid the phylogenetic tree for inferring the relationship between simian malaria parasites in Sabah. PCR results showed that only 1.61% (23/1,425) of the screened An. balabacensis were infected with one or two of the five simian Plasmodispp. found in Sabah, vi Plasmodium coatneyi, P. inui, P. fieldi, P. cynomolgi and P. knowlesi. Sequence analysis of SSU rRNA of Plasmodium isolates showed high percentage of identity within the same Plasmodium sp. group. The phylogenetic tree based on the consensus sequences of P. knowlesi showed 99.7%-100.0% nucleotide identity among the isolates from An. balabacensis, human patients and a long-tailed macaque from the same locality. This is the first study showing high molecular identity between the P. knowlesi isolates from An. balabacensis, human patients and a long-tailed macaque in Sabah. The other common simian Plasmodium spp. found in long-tailed macaques and also detected in An. balabacensis were P. coatneyi, P. inui, P. fieldi and P. cynomolgi. The high percentage identity of nucleotide sequences between the P. knowlesi isolates from the long-tailed macaque, An. balabacensis and human patients suggests a close genetic relationship between the parasites from these

  18. [Study of gametocytes from the Plasmodium "vivax" group: morphology, development in Anopheles and infectivity of Plasmodium yoelii microgametocytes].

    PubMed

    Landau, I; Miltgen, F; Boulard, Y; Chabaud, A G; Baccam, D

    1979-01-01

    The study of the gametocytes of Plasmodium yoelii enabled the differentiation of 4 morphological types: O, I, II and III (in a chronological order) and amongst each of these types the differentiation of healthy and altered gametocytes. These morphological data represent a tool for investigations on the biology of the gametocytes of the "vivax" group. Preliminary experiments bring informations on the evolution of gametocytes and the mechanisms of their infectivity. 1--In experimentaly infected white mice gametocytes of P.y. nigeriensis are infective up to the 3rd-4th day, those of P. y. yoelii until the 5th-6th days. These periods can be shorter when the infection is very virulent or longer when chronical. 2--The drop in infectivity coincides with the increase in number of the altered gametocytes. 3--The loss of infectivity is connected with the condition of the blood: when parasitaemiae are high, it becomes rapidly unsuitable to a normal evolution of the gametocytes: thus, non infective gametocytes acquire a good infectivity in less than two hours when transfered to a clean mouse. 4--The gametocytic composition of the blood taken up by the Anopheles in the capillaries can be very different from that taken at the tail of a Rodent. In the young parasitaemiae, when the Rodents are most infective to the Mosquitoes, there is a considerable enrichment in gametocytes O-I of the blood ingested by the Anopheles as compared to that taken from the Rodents by the usual techniques. This phenomenon could perhaps be explained by the larger size of gametocytes O and I and their retention in the capillaries of the host. 5--The strong infectivity of gametocytes O and I is confirmed by the fact that no infection develops in the Mosquitoes when no such gametocytes are present in the ingested blood. 6--The ageeing of gametocytes appears to be very rapid for gametocytes arising from exo-erythrocytic schizontes reach stage II, 29 hours and stage III, 35 hours, after the rupture of the

  19. Atomic force microscopy of Plasmodium-infected red blood cells: detecting and localizing single molecular recognition events.

    PubMed

    Li, Ang; Rénia, Laurent; Lim, Chwee Teck; Russell, Bruce

    2013-01-01

    Atomic Force Microscopy (AFM) is a powerful tool for exploring the interaction between ligands and receptors, as well as their exact locations on the red cell surface. Here we discuss current and future applications for AFM based single-molecule force spectroscopy to study adhesion of Plasmodium-infected red blood cells. A protocol is provided for simultaneous topography and recognition imaging of the surface of Plasmodium falciparum-infected cells using CD36 functionalized tips.

  20. Molecular typing reveals substantial Plasmodium vivax infection in asymptomatic adults in a rural area of Cameroon.

    PubMed

    Fru-Cho, Jerome; Bumah, Violet V; Safeukui, Innocent; Nkuo-Akenji, Theresa; Titanji, Vincent P K; Haldar, Kasturi

    2014-05-03

    Malaria in Cameroon is due to infections by Plasmodium falciparum and, to a lesser extent, Plasmodium malariae and Plasmodium ovale, but rarely Plasmodium vivax. A recent report suggested "Plasmodium vivax-like" infections around the study area that remained unconfirmed. Therefore, molecular and antigenic typing was used to investigate the prevalence of P. vivax and Duffy in asymptomatic adults resident in Bolifamba. A cross-sectional study was conducted from July 2008 to October 2009. The status of all parasite species was determined by nested PCR in 269 blood samples collected. The P. falciparum and P. vivax anti-MSP/CSP antibody status of each subject was also determined qualitatively by a rapid card assay. Parasite DNA was extracted from a sample infected with three parasite species, purified and sequenced. The Duffy antigen status of 12 subjects infected with P. vivax was also determined by sequencing. In silico web-based tools were used to analyse sequence data for similarities and matches to reference sequences in public DNA databases. The overall malaria parasite prevalence in 269 individuals was 32.3% (87) as determined by PCR. Remarkably, 14.9% (13/87) of infections were caused either exclusively or concomitantly by P. vivax, established both by PCR and microscopic examination of blood smears, in individuals both positive (50%, 6/12) and negative (50%, 6/12) for the Duffy receptor. A triple infection by P. falciparum, P. vivax and P. malariae, was detected in one infected individual. Anti-MSP/CSP antibodies were detected in 72.1% (194/269) of samples, indicating high and continuous exposure to infection through mosquito bites. These data provide the first molecular evidence of P. vivax in Duffy positive and negative Cameroonians and suggest that there may be a significant prevalence of P. vivax infection than expected in the study area. Whether the P. vivax cases were imported or due to expansion of a founder effect was not investigated. Notwithstanding

  1. Hemoparasites in a wild primate: Infection patterns suggest interaction of Plasmodium and Babesia in a lemur species☆

    PubMed Central

    Springer, Andrea; Fichtel, Claudia; Calvignac-Spencer, Sébastien; Leendertz, Fabian H.; Kappeler, Peter M.

    2015-01-01

    Hemoparasites can cause serious morbidity in humans and animals and often involve wildlife reservoirs. Understanding patterns of hemoparasite infections in natural populations can therefore inform about emerging disease risks, especially in the light of climate change and human disruption of natural ecosystems. We investigated the effects of host age, sex, host group size and season on infection patterns of Plasmodium sp., Babesia sp. and filarial nematodes in a population of wild Malagasy primates, Verreaux's sifakas (Propithecus verreauxi), as well as the effects of these infections on hematological variables. We tested 45 blood samples from 36 individuals and identified two species of Plasmodium, one species of Babesia and two species of filarial nematodes. Plasmodium spp. and Babesia sp. infections showed opposite patterns of age-dependency, with babesiosis being prevalent among young animals, while older animals were infected with Plasmodium sp. In addition, Babesia sp. infection was a statistically significant negative predictor of Plasmodium sp. infection. These results suggest that Plasmodium and Babesia parasites may interact within the host, either through cross-immunity or via resource competition, so that Plasmodium infections can only establish after babesiosis has resolved. We found no effects of host sex, host group size and season on hemoparasite infections. Infections showed high prevalences and did not influence hematological variables. This preliminary evidence supports the impression that the hosts and parasites considered in this study appear to be well-adapted to each other, resulting in persistent infections with low pathogenic and probably low zoonotic potential. Our results illustrate the crucial role of biodiversity in host-parasite relationships, specifically how within-host pathogen diversity may regulate the abundance of parasites. PMID:26767166

  2. Transgenic malaria-resistant mosquitoes have a fitness advantage when feeding on Plasmodium-infected blood.

    PubMed

    Marrelli, Mauro T; Li, Chaoyang; Rasgon, Jason L; Jacobs-Lorena, Marcelo

    2007-03-27

    The introduction of genes that impair Plasmodium development into mosquito populations is a strategy being considered for malaria control. The effect of the transgene on mosquito fitness is a crucial parameter influencing the success of this approach. We have previously shown that anopheline mosquitoes expressing the SM1 peptide in the midgut lumen are impaired for transmission of Plasmodium berghei. Moreover, the transgenic mosquitoes had no noticeable fitness load compared with nontransgenic mosquitoes when fed on noninfected mice. Here we show that when fed on mice infected with P. berghei, these transgenic mosquitoes are more fit (higher fecundity and lower mortality) than sibling nontransgenic mosquitoes. In cage experiments, transgenic mosquitoes gradually replaced nontransgenics when mosquitoes were maintained on mice infected with gametocyte-producing parasites (strain ANKA 2.34) but not when maintained on mice infected with gametocyte-deficient parasites (strain ANKA 2.33). These findings suggest that when feeding on Plasmodium-infected blood, transgenic malaria-resistant mosquitoes have a selective advantage over nontransgenic mosquitoes. This fitness advantage has important implications for devising malaria control strategies by means of genetic modification of mosquitoes.

  3. Cryo scanning electron microscopy of Plasmodium falciparum-infected erythrocytes.

    PubMed

    Hempel, Casper

    2017-07-01

    Plasmodium falciparum invades erythrocytes as an essential part of their life cycle. While living inside erythrocytes, the parasite remodels the cell's intracellular organization as well as its outer surface. Late trophozoite-stage parasites and schizonts introduce numerous small protrusions on the erythrocyte surface, called knobs. Current methods for studying these knobs include atomic force microscopy and electron microscopy. Standard electron microscopy methods rely on chemical fixation and dehydration modifying cell size. Here, a novel method is presented using rapid freezing and scanning electron microscopy under cryogenic conditions allowing for high resolution and magnification of erythrocytes. This novel technique can be used for precise estimates of knob density and for studies on cytoadhesion. © 2017 APMIS. Published by John Wiley & Sons Ltd.

  4. Epidemiology of Plasmodium relictum infection in the house sparrow.

    PubMed

    Bichet, Coraline; Sorci, Gabriele; Robert, Alexandre; Julliard, Romain; Lendvai, Adám Z; Chastel, Olivier; Garnier, Stephane; Loiseau, Claire

    2014-02-01

    In vertebrates, multiple host characteristics and environmental factors are known to influence infectious disease dynamics. Here, we investigated variability in prevalence and parasitemia of Plasmodium relictum in the house sparrow ( Passer domesticus ) across a large number of rural and urban populations (n = 16). We found that prevalence was not predicted by any of the host traits investigated (age, sex, body mass, or wing length). However, parasitemia was significantly higher in females when compared to males and in 1-yr-olds as compared to older individuals. Neither prevalence nor parasitemia differed according to habitat type (urban vs. rural). These results suggest that inter-population variation in parasitemia depends on host intrinsic factors whereas variation in prevalence could be due to environmental differences between populations, such as climatic variables that might affect the abundance of vectors. This large-scale study gives us a better understanding of the key factors involved in the epidemiology of avian malaria.

  5. Theoretical models for near forward light scattering by a Plasmodium falciparum infected red blood cell

    NASA Astrophysics Data System (ADS)

    Sharma, S. K.

    2012-12-01

    A number of experimental elastic light scattering studies have been performed in the past few years with the aim of developing automated in vivo tools for differentiating a healthy red blood cell from a Plasmodium falciparum infected cell. This paper examines some theoretical aspects of the problem. An attempt has been made to simulate the scattering patterns of healthy as well as infected individual red blood cells. Two models, namely, a homogeneous sphere model and a coated sphere model have been considered. The scattering patterns predicted by these models are examined. A possible method for discriminating infected red blood cells from healthy ones has been suggested.

  6. Changes in brain metabolites in experimental cerebral malaria infection with plasmodium berghei ANKA: a literature review.

    PubMed

    Sheikh, Ali Sibtain Farooq; Sheikh, Saman Ali; Mohamed, Mona Adel

    2014-10-01

    In this paper, we have collected the findings of available literature focusing on brain metabolites by spectroscopy in the murine model of cerebral malaria disease. The literature search for experimental cerebral malaria (ECM) and spectroscopy using National Institute of Health's PubMed database provided us with 9 peer-reviewed publications. These publications have used mice infected with Plasmodium Berghei (PbA) Antwerpen-Kasapa (ANKA) strain to mimic the human infection with Plasmodium falciparum. Brain ischaemia, as depicted by increased lactate and alanine concentrations, as well as decreased aspartate and adenosine triphosphate levels, play a key role in ECM. Lowering the lactate levels by using dichloroacetate has been shown to improve survival. Significant cellular injury has also been documented through decreased N-acetylaspartate and glycerophosphocholine levels. The advantage of using spectroscopic technique provide important functional information which helps determine the aetiology, pathogenesis, progression, and monitoring of treatment as well as predicting prognosis in the clinical setting of cerebral malaria.

  7. A zoonotic human infection with simian malaria, Plasmodium knowlesi, in Central Kalimantan, Indonesia.

    PubMed

    Setiadi, Wuryantari; Sudoyo, Herawati; Trimarsanto, Hidayat; Sihite, Boy Adventus; Saragih, Riahdo Juliarman; Juliawaty, Rita; Wangsamuda, Suradi; Asih, Puji Budi Setia; Syafruddin, Din

    2016-04-16

    The Indonesian archipelago is endemic for malaria. Although Plasmodium falciparum and P. vivax are the most common causes for malaria cases, P. malariae and P. ovale are also present in certain regions. Zoonotic case of malaria had just became the attention of public health communities after the Serawak study in 2004. However, zoonotic case in Indonesia is still under reported; only one published report of knowlesi malaria in South Kalimantan in 2010. A case of Plasmodium knowlesi infection in a worker from a charcoal mining company in Central Kalimantan, Indonesia was described. The worker suffered from fever following his visit to a lowland forest being cut and converted into a new mining location. This study confirmed a zoonotic infection using polymerase chain reaction amplification and Sanger sequencing of plasmodial DNA encoding the mitochondrial cytochrome c oxidase subunit I (mtCOI).

  8. Lactate dehydrogenase as a marker of Plasmodium infection in malaria vector Anopheles.

    PubMed

    Riandey, M F; Sannier, C; Peltre, G; Monteny, N; Cavaleyra, M

    1996-06-01

    Lactate dehydrogenase (Ldh) electrophoresis showed the presence of Plasmodium yoelii yoelii in Anopheles stephensi and An. gambiae. The Ldh appeared as an additional band (pLdh) whose activity was more intense with 3-acetyl pyridine adenine dinucleotide as coenzyme than with beta nicotin-amide adenine dinucleotide. Several allelic forms occurred both in the vector and the host. The isoelectric point of Ldh, similar in the vector and host, differed from those of Ldh from mosquito and mouse. The presence of pLdh was detected from the 2nd to the 28th day of infection. The pLdh appeared to be proportional to the number of sporozoites present in infected salivary glands. However, pLdh was not found in salivary glands or midguts, but it was detected in the rest of the corresponding mosquito. The origin and use of pLdh as a marker of Plasmodium in its vector is discussed.

  9. A Nature-Inspired Betalainic Probe for Live-Cell Imaging of Plasmodium-Infected Erythrocytes

    PubMed Central

    Gonçalves, Letícia Christina Pires; Tonelli, Renata Rosito; Bagnaresi, Piero; Mortara, Renato Arruda; Ferreira, Antonio Gilberto; Bastos, Erick Leite

    2013-01-01

    A model betalainic dye was semisynthesized from betanin, the magenta pigment of the red beet, and was effective for live-cell imaging of Plasmodium-infected red blood cells. This water-soluble fluorescent probe is photostable, excitable in the visible region and cell membrane-permeable, and its photophysical properties are not notably pH-sensitive. Fluorescence imaging microscopy of erythrocytes infected with Plasmodium falciparum, a causative agent of malaria in humans, showed that only the parasite was stained. Z-stacking analysis suggested that the probe accumulates proximal to the nucleus of the parasite. Indicaxanthin, one of the natural fluorescent betalains found in the petals of certain flowers, did not stain the parasite or the red blood cell. PMID:23342028

  10. Transport mechanisms in Plasmodium-infected erythrocytes: lipid rafts and a tubovesicular network.

    PubMed

    Haldar, K; Samuel, B U; Mohandas, N; Harrison, T; Hiller, N L

    2001-10-01

    The mature human erythrocyte is a simple cell that is devoid of intracellular organelles and does not show endocytic or phagocytic activity at the plasma membrane. However, following infection by Plasmodium, the erythrocyte undergoes several morphological and functional changes. Parasite-derived proteins are exported into the erythrocyte cytoplasm and to the membrane, while several proteins are localised to the parasitophorous vacuolar membrane and to the tubovesicular membranous network structures surrounding the parasite. Recent evidence indicates that multiple host proteins, independent of the type of their membrane anchor, that exist in detergent-resistant membrane (DRM) rafts or microdomains enter this apicomplexan vacuole. The internalised host components along with the parasite-encoded transmembrane protein PfEXP1 can be detected as DRM rafts in the vacuole. It appears that in Plasmodium-infected erythrocytes lipid rafts may play a role in endovacuolation and macromolecular transport.

  11. Experimental Plasmodium vivax infection of key Anopheles species from the Brazilian Amazon

    PubMed Central

    2013-01-01

    Background Anopheles darlingi is the major malaria vector in countries located in the Amazon region. Anopheles aquasalis and Anopheles albitarsis s.l. are also proven vectors in this region. Anopheles nuneztovari s.l. and Anopheles triannulatus s.l. were found infected with Plasmodium vivax; however, their status as vectors is not yet well defined. Knowledge of susceptibility of Amazon anopheline populations to Plasmodium infection is necessary to better understand their vector capacity. Laboratory colonization of An. darlingi, the main Amazon vector, has proven to be difficult and presently An. aquasalis is the only available autonomous colony. Methods Larvae of An. darlingi, An. albitarsis s.l., An. nuneztovari s.l. and An. triannulatus s.l. were collected in the field and reared until adult stage. Adults of An. aquasalis were obtained from a well-established colony. Mosquitoes were blood-fed using a membrane-feeding device containing infected blood from malarial patients. The infection of the distinct Anopheles species was evaluated by the impact variance of the following parameters: (a) parasitaemia density; (b) blood serum inactivation of the infective bloodmeal; (c) influence of gametocyte number on infection rates and number of oocysts. The goal of this work was to compare the susceptibility to P. vivax of four field-collected Anopheles species with colonized An. aquasalis. Results All Anopheles species tested were susceptible to P. vivax infection, nevertheless the proportion of infected mosquitoes and the infection intensity measured by oocyst number varied significantly among species. Inactivation of the blood serum prior to mosquito feeding increased infection rates in An. darlingi and An. triannulatus s.l., but was diminished in An. albitarsis s.l. and An. aquasalis. There was a positive correlation between gametocyte density and the infection rate in all tests (Z = −8.37; p < 0.001) but varied among the mosquito species. Anopheles albitarsis

  12. Experimental Plasmodium vivax infection of key Anopheles species from the Brazilian Amazon.

    PubMed

    Rios-Velásquez, Claudia M; Martins-Campos, Keillen M; Simões, Rejane C; Izzo, Thiago; dos Santos, Edineuza V; Pessoa, Felipe A C; Lima, José B P; Monteiro, Wuelton M; Secundino, Nágila F C; Lacerda, Marcus V G; Tadei, Wanderli P; Pimenta, Paulo F P

    2013-12-21

    Anopheles darlingi is the major malaria vector in countries located in the Amazon region. Anopheles aquasalis and Anopheles albitarsis s.l. are also proven vectors in this region. Anopheles nuneztovari s.l. and Anopheles triannulatus s.l. were found infected with Plasmodium vivax; however, their status as vectors is not yet well defined. Knowledge of susceptibility of Amazon anopheline populations to Plasmodium infection is necessary to better understand their vector capacity. Laboratory colonization of An. darlingi, the main Amazon vector, has proven to be difficult and presently An. aquasalis is the only available autonomous colony. Larvae of An. darlingi, An. albitarsis s.l., An. nuneztovari s.l. and An. triannulatus s.l. were collected in the field and reared until adult stage. Adults of An. aquasalis were obtained from a well-established colony. Mosquitoes were blood-fed using a membrane-feeding device containing infected blood from malarial patients.The infection of the distinct Anopheles species was evaluated by the impact variance of the following parameters: (a) parasitaemia density; (b) blood serum inactivation of the infective bloodmeal; (c) influence of gametocyte number on infection rates and number of oocysts. The goal of this work was to compare the susceptibility to P. vivax of four field-collected Anopheles species with colonized An. aquasalis. All Anopheles species tested were susceptible to P. vivax infection, nevertheless the proportion of infected mosquitoes and the infection intensity measured by oocyst number varied significantly among species. Inactivation of the blood serum prior to mosquito feeding increased infection rates in An. darlingi and An. triannulatus s.l., but was diminished in An. albitarsis s.l. and An. aquasalis. There was a positive correlation between gametocyte density and the infection rate in all tests (Z = -8.37; p < 0.001) but varied among the mosquito species. Anopheles albitarsis s.l., An. aquasalis and An

  13. Kinome-Wide RNAi Screen Implicates at Least 5 Host Hepatocyte Kinases in Plasmodium Sporozoite Infection

    PubMed Central

    Hannus, Michael; Martin, Cécilie; Real, Eliana; Gonçalves, Lígia A.; Carret, Céline; Dorkin, Robert; Röhl, Ingo; Jahn-Hoffmann, Kerstin; Luty, Adrian J. F.; Sauerwein, Robert; Echeverri, Christophe J.; Mota, Maria M.

    2008-01-01

    Plasmodium sporozoites, the causative agent of malaria, are injected into their vertebrate host through the bite of an infected Anopheles mosquito, homing to the liver where they invade hepatocytes to proliferate and develop into merozoites that, upon reaching the bloodstream, give rise to the clinical phase of infection. To investigate how host cell signal transduction pathways affect hepatocyte infection, we used RNAi to systematically test the entire kinome and associated genes in human Huh7 hepatoma cells for their potential roles during infection by P. berghei sporozoites. The three-phase screen covered 727 genes, which were tested with a total of 2,307 individual siRNAs using an automated microscopy assay to quantify infection rates and qRT-PCR to assess silencing levels. Five protein kinases thereby emerged as top hits, all of which caused significant reductions in infection when silenced by RNAi. Follow-up validation experiments on one of these hits, PKCς (PKCzeta), confirmed the physiological relevance of our findings by reproducing the inhibitory effect on P. berghei infection in adult mice treated systemically with liposome-formulated PKCς-targeting siRNAs. Additional cell-based analyses using a pseudo-substrate inhibitor of PKCς added further RNAi-independent support, indicating a role for host PKCς on the invasion of hepatocytes by sporozoites. This study represents the first comprehensive, functional genomics-driven identification of novel host factors involved in Plasmodium sporozoite infection. PMID:18989463

  14. Acute respiratory distress syndrome and acute renal failure from Plasmodium ovale infection with fatal outcome.

    PubMed

    Lau, Yee-Ling; Lee, Wenn-Chyau; Tan, Lian-Huat; Kamarulzaman, Adeeba; Syed Omar, Sharifah Faridah; Fong, Mun-Yik; Cheong, Fei-Wen; Mahmud, Rohela

    2013-11-04

    Plasmodium ovale is one of the causative agents of human malaria. Plasmodium ovale infection has long been thought to be non-fatal. Due to its lower morbidity, P. ovale receives little attention in malaria research. Two Malaysians went to Nigeria for two weeks. After returning to Malaysia, they fell sick and were admitted to different hospitals. Plasmodium ovale parasites were identified from blood smears of these patients. The species identification was further confirmed with nested PCR. One of them was successfully treated with no incident of relapse within 12-month medical follow-up. The other patient came down with malaria-induced respiratory complication during the course of treatment. Although parasites were cleared off the circulation, the patient's condition worsened. He succumbed to multiple complications including acute respiratory distress syndrome and acute renal failure. Sequencing of the malaria parasite DNA from both cases, followed by multiple sequence alignment and phylogenetic tree construction suggested that the causative agent for both malaria cases was P. ovale curtisi. In this report, the differences between both cases were discussed, and the potential capability of P. ovale in causing severe complications and death as seen in this case report was highlighted. Plasmodium ovale is potentially capable of causing severe complications, if not death. Complete travel and clinical history of malaria patient are vital for successful diagnoses and treatment. Monitoring of respiratory and renal function of malaria patients, regardless of the species of malaria parasites involved is crucial during the course of hospital admission.

  15. Plasmodium chabaudi infection induces AID expression in transitional and marginal zone B cells

    PubMed Central

    Wilmore, Joel R.; Maue, Alexander C.

    2016-01-01

    Abstract Introduction Endemic Burkitt's lymphoma (eBL) is associated with Epstein–Barr virus and repeated malaria infections. A defining feature of eBL is the translocation of the c‐myc oncogene to the control of the immunoglobulin promoter. Activation‐induced cytidine deaminase (AID) has been shown to be critical for this translocation. Malaria infection induces AID in germinal center B cells, but whether malaria infection more broadly affects AID activation in extrafollicular B cells is unknown. Methods We either stimulated purified B cells from AID‐green fluorescence protein (GFP) reporter mice or infected AID‐GFP mice with Plasmodium chabaudi, AID fluorescence was monitored in B cell subsets by flow cytometry. Results In vitro analysis of B cells from these mice revealed that CpG (a Toll‐like receptor 9 ligand) was a potent inducer of AID in both mature and immature B cell subsets. Infection of AID‐GFP mice with Plasmodium chabaudi demonstrated that AID expression occurs in transitional and marginal zone B cells during acute malaria infection. Transitional B cells were also capable of differentiating into antibody secreting cells when stimulated in vitro with CpG when isolated from a P. chabaudi‐infected mouse. Conclusions These data suggest that P. chabaudi is capable of inducing AID expression in B cell subsets that do not participate in the germinal center reaction, suggesting an alternative role for malaria in the etiology of eBL. PMID:27980783

  16. Antimalarial Potential of Carica papaya and Vernonia amygdalina in Mice Infected with Plasmodium berghei

    PubMed Central

    Habila, Nathan; Ikwebe, Joseph; Upev, Vincent A.; Isaac, Omiagocho T.

    2016-01-01

    The study determined if administration of Vernonia amygdalina and Carica papaya plants provides synergistic effects in ameliorating plasmodium infection in mice. Thirty mice (17.88–25.3 g) were divided into 6 groups of 5 mice each. Group 1 was normal control, while groups 2–6 were intraperitoneally inoculated 2.5 × 107 Plasmodium berghei parasitized red blood cell, followed by daily administration of 350 mg/kg aqueous leaf extracts after establishment of infection. Group 2 was disease control, while group 6 was treated with standard drug for four consecutive days. The results showed significant (P < 0.05) reduction in percentage of parasite load between the infected treatment groups and disease control group at day 3 after infection, which remained consistent until the end of the experiment. All infected treated groups showed significant (P < 0.05) increases in RBC and PCV recovery compared to the disease control, with the exception of WBC. There was insignificant (P > 0.05) change in mean body weight of all treated groups except in disease control group. Histological studies of the infected mice indicate recovery of hepatic cells from congested black pigmentation. The reduction in parasite load and recovery of hepatic cell damage/hematological parameters were induced by these plant extracts. This highlighted the important usage of the plant in traditional remedy of malaria infection. PMID:28042299

  17. Antimalarial Potential of Carica papaya and Vernonia amygdalina in Mice Infected with Plasmodium berghei.

    PubMed

    Okpe, Oche; Habila, Nathan; Ikwebe, Joseph; Upev, Vincent A; Okoduwa, Stanley I R; Isaac, Omiagocho T

    2016-01-01

    The study determined if administration of Vernonia amygdalina and Carica papaya plants provides synergistic effects in ameliorating plasmodium infection in mice. Thirty mice (17.88-25.3 g) were divided into 6 groups of 5 mice each. Group 1 was normal control, while groups 2-6 were intraperitoneally inoculated 2.5 × 10(7)Plasmodium berghei parasitized red blood cell, followed by daily administration of 350 mg/kg aqueous leaf extracts after establishment of infection. Group 2 was disease control, while group 6 was treated with standard drug for four consecutive days. The results showed significant (P < 0.05) reduction in percentage of parasite load between the infected treatment groups and disease control group at day 3 after infection, which remained consistent until the end of the experiment. All infected treated groups showed significant (P < 0.05) increases in RBC and PCV recovery compared to the disease control, with the exception of WBC. There was insignificant (P > 0.05) change in mean body weight of all treated groups except in disease control group. Histological studies of the infected mice indicate recovery of hepatic cells from congested black pigmentation. The reduction in parasite load and recovery of hepatic cell damage/hematological parameters were induced by these plant extracts. This highlighted the important usage of the plant in traditional remedy of malaria infection.

  18. Cytoadhesion of Plasmodium falciparum-infected erythrocytes and the infected placenta: a two-way pathway.

    PubMed

    Costa, F T M; Avril, M; Nogueira, P A; Gysin, J

    2006-12-01

    Malaria is undoubtedly the world's most devastating parasitic disease, affecting 300 to 500 million people every year. Some cases of Plasmodium falciparum infection progress to the deadly forms of the disease responsible for 1 to 3 million deaths annually. P. falciparum-infected erythrocytes adhere to host receptors in the deep microvasculature of several organs. The cytoadhesion of infected erythrocytes to placental syncytiotrophoblast receptors leads to pregnancy-associated malaria (PAM). This specific maternal-fetal syndrome causes maternal anemia, low birth weight and the death of 62,000 to 363,000 infants per year in sub-Saharan Africa, and thus has a poor outcome for both mother and fetus. However, PAM and non-PAM parasites have been shown to differ antigenically and genetically. After multiple pregnancies, women from different geographical areas develop adhesion-blocking antibodies that protect against placental parasitemia and clinical symptoms of PAM. The recent description of a new parasite ligand encoded by the var2CSA gene as the only gene up-regulated in PAM parasites renders the development of an anti-PAM vaccine more feasible. The search for a vaccine to prevent P. falciparum sequestration in the placenta by eliciting adhesion-blocking antibodies and a cellular immune response, and the development of new methods for evaluating such antibodies should be key priorities in mother-child health programs in areas of endemic malaria. This review summarizes the main molecular, immunological and physiopathological aspects of PAM, including findings related to new targets in the P. falciparum var gene family. Finally, we focus on a new methodology for mimicking cytoadhesion under blood flow conditions in human placental tissue.

  19. A Novel Model of Asymptomatic Plasmodium Parasitemia That Recapitulates Elements of the Human Immune Response to Chronic Infection

    PubMed Central

    Baccarella, Alyssa; Craft, Joshua F.; Boyle, Michelle J.; McIntyre, Tara I.; Wood, Matthew D.; Thorn, Kurt S.; Anidi, Chioma; Bayat, Aqieda; Chung, Me Ree; Hamburger, Rebecca; Kim, Chris Y.; Pearman, Emily; Pham, Jennifer; Tang, Jia J.; Boon, Louis; Kamya, Moses R.; Dorsey, Grant; Feeney, Margaret E.; Kim, Charles C.

    2016-01-01

    In humans, immunity to Plasmodium sp. generally takes the form of protection from symptomatic malaria (i.e., 'clinical immunity') rather than infection ('sterilizing immunity'). In contrast, mice infected with Plasmodium develop sterilizing immunity, hindering progress in understanding the mechanistic basis of clinical immunity. Here we present a novel model in which mice persistently infected with P. chabaudi exhibit limited clinical symptoms despite sustaining patent parasite burdens for many months. Characterization of immune responses in persistently infected mice revealed development of CD4+ T cell exhaustion, increased production of IL-10, and expansion of B cells with an atypical surface phenotype. Additionally, persistently infected mice displayed a dramatic increase in circulating nonclassical monocytes, a phenomenon that we also observed in humans with both chronic Plasmodium exposure and asymptomatic infection. Following pharmacological clearance of infection, previously persistently infected mice could not control a secondary challenge, indicating that persistent infection disrupts the sterilizing immunity that typically develops in mouse models of acute infection. This study establishes an animal model of asymptomatic, persistent Plasmodium infection that recapitulates several central aspects of the immune response in chronically exposed humans. As such, it provides a novel tool for dissection of immune responses that may prevent development of sterilizing immunity and limit pathology during infection. PMID:27583554

  20. Effects of chronic avian malaria (Plasmodium relictum) infection on reproductive success of Hawaii Amakihi (Hemignathus virens)

    USGS Publications Warehouse

    Kilpatrick, A.M.; Lapointe, D.A.; Atkinson, C.T.; Woodworth, B.L.; Lease, J.K.; Reiter, M.E.; Gross, K.

    2006-01-01

    We studied the effects of chronic avian malaria (Plasmodium relictum) infections on the reproductive success of a native Hawaiian honeycreeper, Hawaii Amakihi (Hemignathus virens). Chronic malaria infections in male and female parents did not significantly reduce reproductive success as measured by clutch size, hatching success, fledging mass, number of nestlings fledged, nesting success (daily survival rate), and minimum fledgling survival. In fact, nesting success of pairs with chronically infected males was significantly higher than those with uninfected males (76% vs. 38%), and offspring that had at least one parent that had survived the acute phase of malaria infection had a significantly greater chance of being resighted the following year (25% vs. 10%). The reproduction and survival of infected birds were sufficient for a per-capita population growth rate >1, which suggests that chronically infected Hawaii Amakihi could support a growing population. ?? The American Ornithologists' Union, 2006.

  1. Mixed-species aggregations in arthropods.

    PubMed

    Boulay, Julien; Aubernon, Cindy; Ruxton, Graeme D; Hédouin, Valéry; Deneubourg, Jean-Louis; Charabidzé, Damien

    2017-06-28

    This review offers the first synthesis of the research on mixed-species groupings of arthropods and highlights the behavioural and evolutionary questions raised by such behaviour. Mixed-species groups are commonly found in mammals and birds. Such groups are also observed in a large range of arthropod taxa independent of their level of sociality. Several examples are presented to highlight the mechanisms underlying such groupings, particularly the evidence for phylogenetic proximity between members that promotes cross-species recognition. The advantages offered by such aggregates are described and discussed. These advantages can be attributed to the increase in group size and could be identical to those of non-mixed groupings, but competition-cooperation dynamics might also be involved, and such effects may differ between homo- and heterospecific groups. We discuss three extreme cases of interspecific recognition that are likely involved in mixed-species groups as vectors for cross-species aggregation: tolerance behaviour between two social species, one-way mechanism in which one species is attractive to others and two-way mechanism of mutual attraction. As shown in this review, the study of mixed-species groups offers biologists an interesting way to explore the frontiers of cooperation-competition, including the process of sympatric speciation. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  2. Resistance to Therapies for Infection by Plasmodium vivax

    PubMed Central

    Baird, J. Kevin

    2009-01-01

    The gravity of the threat posed by vivax malaria to public health has been poorly appreciated. The widely held misperception of Plasmodium vivax as being relatively infrequent, benign, and easily treated explains its nearly complete neglect across the range of biological and clinical research. Recent evidence suggests a far higher and more-severe disease burden imposed by increasingly drug-resistant parasites. The two frontline therapies against vivax malaria, chloroquine and primaquine, may be failing. Despite 60 years of nearly continuous use of these drugs, their respective mechanisms of activity, resistance, and toxicity remain unknown. Although standardized means of assessing therapeutic efficacy against blood and liver stages have not been developed, this review examines the provisional in vivo, ex vivo, and animal model systems for doing so. The rationale, design, and interpretation of clinical trials of therapies for vivax malaria are discussed in the context of the nuance and ambiguity imposed by the hypnozoite. Fielding new drug therapies against real-world vivax malaria may require a reworking of the strategic framework of drug development, namely, the conception, testing, and evaluation of sets of drugs designed for the cure of both blood and liver asexual stages as well as the sexual blood stages within a single therapeutic regimen. PMID:19597012

  3. Analysis of Breath Specimens for Biomarkers of Plasmodium falciparum Infection

    PubMed Central

    Berna, Amalia Z.; McCarthy, James S.; Wang, Rosalind X.; Saliba, Kevin J.; Bravo, Florence G.; Cassells, Julie; Padovan, Benjamin; Trowell, Stephen C.

    2015-01-01

    Currently, the majority of diagnoses of malaria rely on a combination of the patient's clinical presentation and the visualization of parasites on a stained blood film. Breath offers an attractive alternative to blood as the basis for simple, noninvasive diagnosis of infectious diseases. In this study, breath samples were collected from individuals during controlled malaria to determine whether specific malaria-associated volatiles could be detected in breath. We identified 9 compounds whose concentrations varied significantly over the course of malaria: carbon dioxide, isoprene, acetone, benzene, cyclohexanone, and 4 thioethers. The latter group, consisting of allyl methyl sulfide, 1-methylthio-propane, (Z)-1-methylthio-1-propene, and (E)-1-methylthio-1-propene, had not previously been associated with any disease or condition. Before the availability of antimalarial drug treatment, there was evidence of concurrent 48-hour cyclical changes in the levels of both thioethers and parasitemia. When thioether concentrations were subjected to a phase shift of 24 hours, a direct correlation between the parasitemia and volatile levels was revealed. Volatile levels declined monotonically approximately 6.5 hours after initial drug treatment, correlating with clearance of parasitemia. No thioethers were detected in in vitro cultures of Plasmodium falciparum. The metabolic origin of the thioethers is not known, but results suggest that interplay between host and parasite metabolic pathways is involved in the production of these thioethers. PMID:25810441

  4. Analysis of Breath Specimens for Biomarkers of Plasmodium falciparum Infection.

    PubMed

    Berna, Amalia Z; McCarthy, James S; Wang, Rosalind X; Saliba, Kevin J; Bravo, Florence G; Cassells, Julie; Padovan, Benjamin; Trowell, Stephen C

    2015-10-01

    Currently, the majority of diagnoses of malaria rely on a combination of the patient's clinical presentation and the visualization of parasites on a stained blood film. Breath offers an attractive alternative to blood as the basis for simple, noninvasive diagnosis of infectious diseases. In this study, breath samples were collected from individuals during controlled malaria to determine whether specific malaria-associated volatiles could be detected in breath. We identified 9 compounds whose concentrations varied significantly over the course of malaria: carbon dioxide, isoprene, acetone, benzene, cyclohexanone, and 4 thioethers. The latter group, consisting of allyl methyl sulfide, 1-methylthio-propane, (Z)-1-methylthio-1-propene, and (E)-1-methylthio-1-propene, had not previously been associated with any disease or condition. Before the availability of antimalarial drug treatment, there was evidence of concurrent 48-hour cyclical changes in the levels of both thioethers and parasitemia. When thioether concentrations were subjected to a phase shift of 24 hours, a direct correlation between the parasitemia and volatile levels was revealed. Volatile levels declined monotonically approximately 6.5 hours after initial drug treatment, correlating with clearance of parasitemia. No thioethers were detected in in vitro cultures of Plasmodium falciparum. The metabolic origin of the thioethers is not known, but results suggest that interplay between host and parasite metabolic pathways is involved in the production of these thioethers.

  5. Detection of Plasmodium falciparum and Plasmodium vivax subclinical infection in non-endemic region: implications for blood transfusion and malaria epidemiology

    PubMed Central

    2014-01-01

    Background In Brazil, malaria is endemic in the Amazon River basin and non-endemic in the extra-Amazon region, which includes areas of São Paulo state. In this state, a number of autochthonous cases of malaria occur annually, and the prevalence of subclinical infection is unknown. Asymptomatic infections may remain undetected, maintaining transmission of the pathogen, including by blood transfusion. In these report it has been described subclinical Plasmodium infection in blood donors from a blood transfusion centre in São Paulo, Brazil. Methods In this cross-sectional study, representative samples of blood were obtained from 1,108 healthy blood donors at the Fundação Pró-Sangue Hemocentro de São Paulo, the main blood transfusion centre in São Paulo. Malaria exposure was defined by the home region (exposed: forest region; non-exposed: non-forest region). Real-time PCR was used to detect Plasmodium falciparum and Plasmodium vivax. Subclinical malaria cases were geo-referenced. Results Eighty-four (7.41%) blood donors tested positive for Plasmodium; 57 of these were infected by P. falciparum, 25 by P. vivax, and 2 by both. The prevalence of P. falciparum and P. vivax was 5.14 and 2.26, respectively. The overall prevalence ratio (PR) was 3.23 (95% confidence interval (CI) 2.03, 5.13); P. falciparum PR was 16.11 (95% CI 5.87, 44.21) and P. vivax PR was 0.47 (95% CI 0.2, 1.12). Plasmodium falciparum subclinical malaria infection in the Atlantic Forest domain was present in the mountain regions while P. vivax infection was observed in cities from forest-surrounded areas. Conclusions The presence of Plasmodium in healthy blood donors from a region known as non-endemic, which is important in the context of transfusion biosafety, was described. Infected recipients may become asymptomatic carriers and a reservoir for parasites, maintaining their transmission. Furthermore, P. falciparum PR was positively associated with the forest environment, and P. vivax was

  6. Molecular-Based Assay for Simultaneous Detection of Four Plasmodium spp. and Wuchereria bancrofti Infections

    PubMed Central

    Mehlotra, Rajeev K.; Gray, Laurie R.; Blood-Zikursh, Melinda J.; Kloos, Zachary; Henry-Halldin, Cara N.; Tisch, Daniel J.; Thomsen, Edward; Reimer, Lisa; Kastens, Will; Baea, Manasseh; Baea, Kaye; Baisor, Moses; Tarongka, Nandao; Kazura, James W.; Zimmerman, Peter A.

    2010-01-01

    Four major malaria-causing Plasmodium spp. and lymphatic filariasis-causing Wuchereria bancrofti are co-endemic in many tropical and sub-tropical regions. Among molecular diagnostic assays, multiplex polymerase chain reaction (PCR)–based assays for the simultaneous detection of DNAs from these parasite species are currently available only for P. falciparum and W. bancrofti or P. vivax and W. bancrofti. Using a post-PCR oligonucleotide ligation detection reaction–fluorescent microsphere assay (LDR-FMA), we developed a multiplex assay that has the capability to simultaneously detect all four Plasmodium spp. and W. bancrofti infections in blood samples. Compared with microfilarial positivity in the blood, the LDR-FMA assay is highly concordant (91%), sensitive (86%), and specific (94%), and has high reproducibility for Plasmodium spp. (85–93%) and W. bancrofti (90%) diagnoses. The development of this assay for the simultaneous diagnosis of multiple parasitic infections enables efficient screening of large numbers of human blood and mosquito samples from co-endemic areas. PMID:20519596

  7. Acute pancreatitis, ascites, and acute renal failure in Plasmodium vivax malaria infection, a rare complication

    PubMed Central

    Lakhotia, Manoj; Pahadiya, Hans Raj; Kumar, Harish; Singh, Jagdish; Sangappa, Jainapur Ravi; Choudhary, Prakash Kumar

    2015-01-01

    A 22-year-old male presented with 6 days history of intermittent fever with chills, 2 days history of upper abdomen pain, distension of abdomen, and decreased urine output. He was diagnosed to have Plasmodium vivax malaria, acute pancreatitis, ascites, and acute renal failure. These constellations of complications in P. vivax infection have never been reported in the past. The patient responded to intravenous chloroquine and supportive treatment. For renal failure, he required hemodialysis. Acute pancreatitis, ascites, and acute renal failure form an unusual combination in P. vivax infection. PMID:26629455

  8. Epidemiology and Infectivity of Plasmodium falciparum and Plasmodium vivax Gametocytes in Relation to Malaria Control and Elimination

    PubMed Central

    Bousema, Teun; Drakeley, Chris

    2011-01-01

    Summary: Malaria remains a major cause of morbidity and mortality in the tropics, with Plasmodium falciparum responsible for the majority of the disease burden and P. vivax being the geographically most widely distributed cause of malaria. Gametocytes are the sexual-stage parasites that infect Anopheles mosquitoes and mediate the onward transmission of the disease. Gametocytes are poorly studied despite this crucial role, but with a recent resurgence of interest in malaria elimination, the study of gametocytes is in vogue. This review highlights the current state of knowledge with regard to the development and longevity of P. falciparum and P. vivax gametocytes in the human host and the factors influencing their distribution within endemic populations. The evidence for immune responses, antimalarial drugs, and drug resistance influencing infectiousness to mosquitoes is reviewed. We discuss how the application of molecular techniques has led to the identification of submicroscopic gametocyte carriage and to a reassessment of the human infectious reservoir. These components are drawn together to show how control measures that aim to reduce malaria transmission, such as mass drug administration and a transmission-blocking vaccine, might better be deployed. PMID:21482730

  9. ABO Blood Groups Influence Macrophage-mediated Phagocytosis of Plasmodium falciparum-infected Erythrocytes

    PubMed Central

    Branch, Donald R.; Hult, Annika K.; Olsson, Martin L.; Liles, W. Conrad; Cserti-Gazdewich, Christine M.; Kain, Kevin C.

    2012-01-01

    Erythrocyte polymorphisms associated with a survival advantage to Plasmodium falciparum infection have undergone positive selection. There is a predominance of blood group O in malaria-endemic regions, and several lines of evidence suggest that ABO blood groups may influence the outcome of P. falciparum infection. Based on the hypothesis that enhanced innate clearance of infected polymorphic erythrocytes is associated with protection from severe malaria, we investigated whether P. falciparum-infected O erythrocytes are more efficiently cleared by macrophages than infected A and B erythrocytes. We show that human macrophages in vitro and mouse monocytes in vivo phagocytose P. falciparum-infected O erythrocytes more avidly than infected A and B erythrocytes and that uptake is associated with increased hemichrome deposition and high molecular weight band 3 aggregates in infected O erythrocytes. Using infected A1, A2, and O erythrocytes, we demonstrate an inverse association of phagocytic capacity with the amount of A antigen on the surface of infected erythrocytes. Finally, we report that enzymatic conversion of B erythrocytes to type as O before infection significantly enhances their uptake by macrophages to observed level comparable to that with infected O wild-type erythrocytes. These data provide the first evidence that ABO blood group antigens influence macrophage clearance of P. falciparum-infected erythrocytes and suggest an additional mechanism by which blood group O may confer resistance to severe malaria. PMID:23071435

  10. The SLC4A1 gene is under differential selective pressure in primates infected by Plasmodium falciparum and related parasites.

    PubMed

    Steiper, Michael E; Walsh, Fiona; Zichello, Julia M

    2012-07-01

    Malaria is a disease caused by Plasmodium parasites and is responsible for high mortality in humans. This disease is caused by four different species of Plasmodium though the main source of mortality is Plasmodium falciparum. Humans have a number of genetic adaptations that act to combat Plasmodium. One adaptation is a deletion in the SLC4A1 gene that leads to Southeast Asian ovalocytosis (SAO). There is evidence that SAO erythrocytes are resistant to multiple Plasmodium species. Here we analyze SLC4A1 in 23 primates and mammals to test for differential selective pressures among different primate lineages. Because primates are infected with both human Plasmodium parasites and their relatives, this analysis can be used to test which human Plasmodium parasite is the likely target of SAO. A significantly different pattern of molecular evolution was found in humans and African apes, species that are infected by P. falciparum and its relatives. This effect was restricted to the cytosolic domain of the SLC4A1 gene. The evidence is consistent with a different selective regime operating on this gene domain in humans and African apes, when compared to other primates and mammals. Alternatively, this pattern is consistent with a relaxation of selection or weak adaptive evolution operating on a small number of amino acids. The adaptive interpretation of the results is consistent with the SAO allele of the SLC4A1 gene interacting with P. falciparum in humans, rather than other Plasmodium parasites. However, additional investigation of the relationship between SLC4A1 variants and Plasmodium in humans and African apes is required to test whether the different selective regime in humans and African apes is due to natural selection or relaxed constraint. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. Mitochondrial genes support a common origin of rodent malaria parasites and Plasmodium falciparum's relatives infecting great apes.

    PubMed

    Blanquart, Samuel; Gascuel, Olivier

    2011-03-15

    Plasmodium falciparum is responsible for the most acute form of human malaria. Most recent studies demonstrate that it belongs to a monophyletic lineage specialized in the infection of great ape hosts. Several other Plasmodium species cause human malaria. They all belong to another distinct lineage of parasites which infect a wider range of primate species. All known mammalian malaria parasites appear to be monophyletic. Their clade includes the two previous distinct lineages of parasites of primates and great apes, one lineage of rodent parasites, and presumably Hepatocystis species. Plasmodium falciparum and great ape parasites are commonly thought to be the sister-group of all other mammal-infecting malaria parasites. However, some studies supported contradictory origins and found parasites of great apes to be closer to those of rodents, or to those of other primates. To distinguish between these mutually exclusive hypotheses on the origin of Plasmodium falciparum and its great ape infecting relatives, we performed a comprehensive phylogenetic analysis based on a data set of three mitochondrial genes from 33 to 84 malaria parasites. We showed that malarial mitochondrial genes have evolved slowly and are compositionally homogeneous. We estimated their phylogenetic relationships using Bayesian and maximum-likelihood methods. Inferred trees were checked for their robustness to the (i) site selection, (ii) assumptions of various probabilistic models, and (iii) taxon sampling. Our results robustly support a common ancestry of rodent parasites and Plasmodium falciparum's relatives infecting great apes. Our results refute the most common view of the origin of great ape malaria parasites, and instead demonstrate the robustness of a less well-established phylogenetic hypothesis, under which Plasmodium falciparum and its relatives infecting great apes are closely related to rodent parasites. This study sheds light on the evolutionary history of Plasmodium falciparum, a

  12. Identification of novel membrane structures in Plasmodium falciparum infected erythrocytes.

    PubMed

    Clavijo, C A; Mora, C A; Winograd, E

    1998-01-01

    Little is known about the molecular mechanisms underlying the release of merozoites from malaria infected erythrocytes. In this study membranous structures present in the culture medium at the time of merozoite release have been characterized. Biochemical and ultrastructural evidence indicate that membranous structures consist of the infected erythrocyte membrane, the parasitophorous vacuolar membrane and a residual body containing electron dense material. These are subcellular compartments expected in a structure that arises as a consequence of merozoite release from the infected cell. Ultrastructural studies show that a novel structure extends from the former parasite compartment to the surface membrane. Since these membrane modifications are detected only after merozoites have been released from the infected erythrocyte, it is proposed that they might play a role in the release of merozoites from the host cell.

  13. Odours of Plasmodium falciparum-infected participants influence mosquito-host interactions.

    PubMed

    de Boer, Jetske G; Robinson, Ailie; Powers, Stephen J; Burgers, Saskia L G E; Caulfield, John C; Birkett, Michael A; Smallegange, Renate C; van Genderen, Perry J J; Bousema, Teun; Sauerwein, Robert W; Pickett, John A; Takken, Willem; Logan, James G

    2017-08-24

    Malaria parasites are thought to influence mosquito attraction to human hosts, a phenomenon that may enhance parasite transmission. This is likely mediated by alterations in host odour because of its importance in mosquito host-searching behaviour. Here, we report that the human skin odour profile is affected by malaria infection. We compared the chemical composition and attractiveness to Anopheles coluzzii mosquitoes of skin odours from participants that were infected by Controlled Human Malaria Infection with Plasmodium falciparum. Skin odour composition differed between parasitologically negative and positive samples, with positive samples collected on average two days after parasites emerged from the liver into the blood, being associated with low densities of asexual parasites and the absence of gametocytes. We found a significant reduction in mosquito attraction to skin odour during infection for one experiment, but not in a second experiment, possibly due to differences in parasite strain. However, it does raise the possibility that infection can affect mosquito behaviour. Indeed, several volatile compounds were identified that can influence mosquito behaviour, including 2- and 3-methylbutanal, 3-hydroxy-2-butanone, and 6-methyl-5-hepten-2-one. To better understand the impact of our findings on Plasmodium transmission, controlled studies are needed in participants with gametocytes and higher parasite densities.

  14. Simian malaria in the Brazilian Atlantic forest: first description of natural infection of capuchin monkeys (Cebinae subfamily) by Plasmodium simium.

    PubMed

    de Alvarenga, Denise Anete Madureira; de Pina-Costa, Anielle; de Sousa, Taís Nóbrega; Pissinatti, Alcides; Zalis, Mariano G; Suaréz-Mutis, Martha C; Lourenço-de-Oliveira, Ricardo; Brasil, Patrícia; Daniel-Ribeiro, Cláudio Tadeu; de Brito, Cristiana Ferreira Alves

    2015-02-18

    In Brazil, two species of Plasmodium have been described infecting non-human primates, Plasmodium brasilianum and Plasmodium simium. These species are morphologically, genetically and immunologically indistinguishable from the human Plasmodium malariae and Plasmodium vivax parasites, respectively. Plasmodium simium has been observed naturally infecting monkeys of the genera Alouatta and Brachyteles in a restricted area of the Atlantic Forest in the south and southeast regions of Brazil. However, its reported geographical distribution and the diversity of its vertebrate hosts may be underestimated, since available data were largely based on analyses by microscopic examination of peripheral blood, a method with limited sensitivity, considering the potential sub-patent feature of these infections. The present study describes, for the first time, the natural infection of P. simium in capuchin monkeys from the Brazilian Atlantic Forest. Blood samples from 30 non-human primates belonging to nine species kept in the Primate Centre of Rio de Janeiro were collected. Fragments of spleen and liver from one dead monkey found in the neighborhoods of the Primate Centre were also analysed. Molecular diagnosis was performed by nested PCR (18SSU rRNA) and the amplified fragment was sequenced. Thirty per cent of the captive animals were infected with P. simium and/or P. brasilianum. The dead monkey tested positive for DNA of P. simium. For the first time, Cebinae primates (two specimens of genus Cebus and two of genus Sapajos) were found naturally infected by P. simium. The infection was confirmed by sequencing a small fragment of 18SSU rRNA. The results highlight the possibility of infection by P. simium in other species of non-human primates whose impact could be significant for the malaria epidemiology among non-human primates and, if it becomes clear that this P. simium is able to infect monkeys and, eventually, man, also for the maintenance of transmission of human malaria in

  15. Evaluation of three rapid diagnostic tests for the detection of human infections with Plasmodium knowlesi

    PubMed Central

    2014-01-01

    Background Plasmodium knowlesi, a malaria parasite of Southeast Asian macaques, infects humans and can cause fatal malaria. It is difficult to diagnose by microscopy because of morphological similarity to Plasmodium malariae. Nested PCR assay is the most accurate method to distinguish P. knowlesi from other Plasmodium species but is not cost effective in resource-poor settings. Rapid diagnostic tests (RDTs) are recommended for settings where malaria is prevalent. In this study, the effectiveness of three RDTs in detecting P. knowlesi from fresh and frozen patient blood samples was evaluated. Methods Forty malaria patients (28 P. knowlesi, ten P. vivax and two P. falciparum) diagnosed by microscopy were recruited in Sarawak, Malaysian Borneo during a 16-month period. Patient blood samples were used to determine parasitaemia by microscopy, confirm the Plasmodium species present by PCR and evaluate three RDTs: OptiMAL-IT, BinaxNOW® Malaria and Paramax-3. The RDTs were also evaluated using frozen blood samples from 41 knowlesi malaria patients. Results OptiMAL-IT was the most sensitive RDT, with a sensitivity of 71% (20/28; 95% CI = 54-88%) for fresh and 73% (30/41; 95% CI = 59-87%) for frozen knowlesi samples. However, it yielded predominantly falciparum-positive results due to cross-reactivity of the P. falciparum test reagent with P. knowlesi. BinaxNOW® Malaria correctly detected non-P. falciparum malaria in P. knowlesi samples but was the least sensitive, detecting only 29% (8/28; 95% CI = 12-46%) of fresh and 24% (10/41; 95% CI = 11-37%) of frozen samples. The Paramax-3 RDT tested positive for P. vivax with PCR-confirmed P. knowlesi samples with sensitivities of 40% (10/25; 95% CI = 21-59%) with fresh and 32% (13/41; 95% CI = 17-46%) with frozen samples. All RDTs correctly identified P. falciparum- and P. vivax-positive controls with parasitaemias above 2,000 parasites/μl blood. Conclusions The RDTs detected Plasmodium in P. knowlesi-infected blood samples with

  16. Iron overload in Plasmodium berghei-infected placenta as a pathogenesis mechanism of fetal death

    PubMed Central

    Penha-Gonçalves, Carlos; Gozzelino, Raffaella; de Moraes, Luciana V.

    2014-01-01

    Plasmodium infection during gestation may lead to severe clinical manifestations including abortion, stillbirth, intrauterine growth retardation, and low birth weight. Mechanisms underlying such poor pregnancy outcomes are still unclear. In the animal model of severe placental malaria (PM), in utero fetal death frequently occurs and mothers often succumb to infection before or immediately after delivery. Plasmodium berghei-infected erythrocytes (IEs) continuously accumulate in the placenta, where they are then phagocytosed by fetal-derived placental cells, namely trophoblasts. Inside the phagosomes, disruption of IEs leads to the release of non-hemoglobin bound heme, which is subsequently catabolized by heme oxygenase-1 into carbon monoxide, biliverdin, and labile iron. Fine-tuned regulatory mechanisms operate to maintain iron homeostasis, preventing the deleterious effect of iron-induced oxidative stress. Our preliminary results demonstrate that iron overload in trophoblasts of P. berghei-infected placenta is associated with fetal death. Placentas which supported normally developing embryos showed no iron accumulation within the trophoblasts. Placentas from dead fetuses showed massive iron accumulation, which was associated with parasitic burden. Here we present preliminary data suggesting that disruption of iron homeostasis in trophoblasts during the course of PM is a consequence of heme accumulation after intense IE engulfment. We propose that iron overload in placenta is a pathogenic component of PM, contributing to fetal death. The mechanism through which it operates still needs to be elucidated. PMID:25071574

  17. Midgut Microbiota of the Malaria Mosquito Vector Anopheles gambiae and Interactions with Plasmodium falciparum Infection

    PubMed Central

    Boissière, Anne; Tchioffo, Majoline T.; Bachar, Dipankar; Abate, Luc; Marie, Alexandra; Nsango, Sandrine E.; Shahbazkia, Hamid R.; Awono-Ambene, Parfait H.; Levashina, Elena A.; Christen, Richard; Morlais, Isabelle

    2012-01-01

    The susceptibility of Anopheles mosquitoes to Plasmodium infections relies on complex interactions between the insect vector and the malaria parasite. A number of studies have shown that the mosquito innate immune responses play an important role in controlling the malaria infection and that the strength of parasite clearance is under genetic control, but little is known about the influence of environmental factors on the transmission success. We present here evidence that the composition of the vector gut microbiota is one of the major components that determine the outcome of mosquito infections. A. gambiae mosquitoes collected in natural breeding sites from Cameroon were experimentally challenged with a wild P. falciparum isolate, and their gut bacterial content was submitted for pyrosequencing analysis. The meta-taxogenomic approach revealed a broader richness of the midgut bacterial flora than previously described. Unexpectedly, the majority of bacterial species were found in only a small proportion of mosquitoes, and only 20 genera were shared by 80% of individuals. We show that observed differences in gut bacterial flora of adult mosquitoes is a result of breeding in distinct sites, suggesting that the native aquatic source where larvae were grown determines the composition of the midgut microbiota. Importantly, the abundance of Enterobacteriaceae in the mosquito midgut correlates significantly with the Plasmodium infection status. This striking relationship highlights the role of natural gut environment in parasite transmission. Deciphering microbe-pathogen interactions offers new perspectives to control disease transmission. PMID:22693451

  18. Biophysical Properties of Plasmodium falciparum-Infected Erythrocytes from Novel Analysis of the Flicker Phenomena

    NASA Astrophysics Data System (ADS)

    Arie, Takayuki; Jin, Albert; Dvorak, James

    2002-03-01

    Infectious processes often modulate the intrinsic properties of vertebrate cells. We studied the modulation of human erythrocyte flicker during the intra-erythrocytic cycle of Plasmodium falciparum malaria using video microscopy imaging and a data analysis system of our design to extract flicker spectra and lateral cell edge undulations of individual erythrocytes at various stages of infection. The total flicker power, the power weighted mean flicker frequency, the mode amplitudes of lateral undulations, and the time correlation of translation mode was quantified by infectious stage and modeled theoretically. Our results suggest that malaria-infected erythrocytes become increasingly more rigid following infection and provide an insight into the modulation of erythrocyte cytoplasmic viscosity by the parasites. These studies of malaria-infected erythrocytes elucidate the kinetics of both membrane and cellular changes that are relevant to blood microcirculation and improve our understanding of the malaria disease process.

  19. Wolbachia infections in natural Anopheles populations affect egg laying and negatively correlate with Plasmodium development

    PubMed Central

    Shaw, W. Robert; Marcenac, Perrine; Childs, Lauren M.; Buckee, Caroline O.; Baldini, Francesco; Sawadogo, Simon P.; Dabiré, Roch K.; Diabaté, Abdoulaye; Catteruccia, Flaminia

    2016-01-01

    The maternally inherited alpha-proteobacterium Wolbachia has been proposed as a tool to block transmission of devastating mosquito-borne infectious diseases like dengue and malaria. Here we study the reproductive manipulations induced by a recently identified Wolbachia strain that stably infects natural mosquito populations of a major malaria vector, Anopheles coluzzii, in Burkina Faso. We determine that these infections significantly accelerate egg laying but do not induce cytoplasmic incompatibility or sex-ratio distortion, two parasitic reproductive phenotypes that facilitate the spread of other Wolbachia strains within insect hosts. Analysis of 221 blood-fed A. coluzzii females collected from houses shows a negative correlation between the presence of Plasmodium parasites and Wolbachia infection. A mathematical model incorporating these results predicts that infection with these endosymbionts may reduce malaria prevalence in human populations. These data suggest that Wolbachia may be an important player in malaria transmission dynamics in Sub-Saharan Africa. PMID:27243367

  20. A conserved domain targets exported PHISTb family proteins to the periphery of Plasmodium infected erythrocytes

    PubMed Central

    Tarr, Sarah J.; Moon, Robert W.; Hardege, Iris; Osborne, Andrew R.

    2014-01-01

    During blood-stage infection, malaria parasites export numerous proteins to the host erythrocyte. The Poly-Helical Interspersed Sub-Telomeric (PHIST) proteins are an exported family that share a common ‘PRESAN’ domain, and include numerous members in Plasmodium falciparum, Plasmodium vivax and Plasmodium knowlesi. In P. falciparum, PHIST proteins have been implicated in protein trafficking and intercellular communication. A number of PHIST proteins are essential for parasite survival. Here, we identify nine members of the PHISTb sub-class of PHIST proteins, including one protein known to be essential for parasite survival, that localise to the erythrocyte periphery. These proteins have solubility characteristics consistent with their association with the erythrocyte cytoskeleton. Together, an extended PRESAN domain, comprising the PRESAN domain and preceding sequence, form a novel targeting-domain that is sufficient to localise a protein to the erythrocyte periphery. We validate the role of this domain in RESA, thus identifying a cytoskeleton-binding domain in RESA that functions independently of its known spectrin-binding domain. Our data suggest that some PHISTb proteins may act as cross-linkers of the erythrocyte cytoskeleton. We also show for the first time that peripherally-localised PHISTb proteins are encoded in genomes of P. knowlesi and vivax indicating a conserved role for the extended PRESAN domain of these proteins in targeting to the erythrocyte periphery. PMID:25106850

  1. Acute respiratory distress syndrome and acute renal failure from Plasmodium ovale infection with fatal outcome

    PubMed Central

    2013-01-01

    Background Plasmodium ovale is one of the causative agents of human malaria. Plasmodium ovale infection has long been thought to be non-fatal. Due to its lower morbidity, P. ovale receives little attention in malaria research. Methods Two Malaysians went to Nigeria for two weeks. After returning to Malaysia, they fell sick and were admitted to different hospitals. Plasmodium ovale parasites were identified from blood smears of these patients. The species identification was further confirmed with nested PCR. One of them was successfully treated with no incident of relapse within 12-month medical follow-up. The other patient came down with malaria-induced respiratory complication during the course of treatment. Although parasites were cleared off the circulation, the patient’s condition worsened. He succumbed to multiple complications including acute respiratory distress syndrome and acute renal failure. Results Sequencing of the malaria parasite DNA from both cases, followed by multiple sequence alignment and phylogenetic tree construction suggested that the causative agent for both malaria cases was P. ovale curtisi. Discussion In this report, the differences between both cases were discussed, and the potential capability of P. ovale in causing severe complications and death as seen in this case report was highlighted. Conclusion Plasmodium ovale is potentially capable of causing severe complications, if not death. Complete travel and clinical history of malaria patient are vital for successful diagnoses and treatment. Monitoring of respiratory and renal function of malaria patients, regardless of the species of malaria parasites involved is crucial during the course of hospital admission. PMID:24180319

  2. Spatial Effects on the Multiplicity of Plasmodium falciparum Infections

    PubMed Central

    Karl, Stephan; White, Michael T.; Milne, George J.; Gurarie, David; Hay, Simon I.; Barry, Alyssa E.; Felger, Ingrid; Mueller, Ivo

    2016-01-01

    As malaria is being pushed back on many frontiers and global case numbers are declining, accurate measurement and prediction of transmission becomes increasingly difficult. Low transmission settings are characterised by high levels of spatial heterogeneity, which stands in stark contrast to the widely used assumption of spatially homogeneous transmission used in mathematical transmission models for malaria. In the present study an individual-based mathematical malaria transmission model that incorporates multiple parasite clones, variable human exposure and duration of infection, limited mosquito flight distance and most importantly geographically heterogeneous human and mosquito population densities was used to illustrate the differences between homogeneous and heterogeneous transmission assumptions when aiming to predict surrogate indicators of transmission intensity such as population parasite prevalence or multiplicity of infection (MOI). In traditionally highly malaria endemic regions where most of the population harbours malaria parasites, humans are often infected with multiple parasite clones. However, studies have shown also in areas with low overall parasite prevalence, infection with multiple parasite clones is a common occurrence. Mathematical models assuming homogeneous transmission between humans and mosquitoes cannot explain these observations. Heterogeneity of transmission can arise from many factors including acquired immunity, body size and occupational exposure. In this study, we show that spatial heterogeneity has a profound effect on predictions of MOI and parasite prevalence. We illustrate, that models assuming homogeneous transmission underestimate average MOI in low transmission settings when compared to field data and that spatially heterogeneous models predict stable transmission at much lower overall parasite prevalence. Therefore it is very important that models used to guide malaria surveillance and control strategies in low

  3. The energetic budget of Anopheles stephensi infected with Plasmodium chabaudi: is energy depletion a mechanism for virulence?

    PubMed

    Rivero, A; Ferguson, H M

    2003-07-07

    Evidence continues to accumulate showing that the malaria parasites (Plasmodium spp.) reduce the survival and fecundity of their mosquito vectors (Anopheles spp.). Our ability to identify the possible epidemiological and evolutionary consequences of these parasite-induced fitness reductions has been hampered by a poor understanding of the physiological basis of these shifts. Here, we explore whether the reductions in fecundity and longevity are the result of a parasite-mediated depletion or reallocation of the energetic resources of the mosquito. Mosquitoes infected with Plasmodium chabaudi were expected to have less energetic resources than uninfected mosquitoes, and energy levels were predicted to be lowest in mosquitoes infected with the most virulent parasite genotypes. Not only was there no evidence of a parasite-mediated reduction in the overall energetic budget of mosquitoes, but Plasmodium was actually associated with increased levels of glucose, a key insect nutritional and energetic resource. The data strongly suggest the existence of an increase in sugar feeding in mosquitoes infected with Plasmodium. We suggest different adaptive explanations for an enhanced sugar uptake in infected mosquitoes and call for more studies to investigate the physiological role of glucose in the Plasmodium-mosquito interaction.

  4. Relative clonal proportions over time in mixed-genotype infections of the lizard malaria parasite Plasmodium mexicanum.

    PubMed

    Ford, Alice Flynn; Schall, Jos J

    2011-06-01

    Vertebrate hosts of malaria parasites (Plasmodium) often harbour two or more genetically distinct clones of a single species, and interaction among these co-existing clones can play an important role in Plasmodium biology. However, how relative clonal proportions vary over time in a host is still poorly known. Experimental mixed-clone infections of the lizard malaria parasite, Plasmodium mexicanum, were followed in its natural host, the western fence lizard using microsatellite markers to determine the relative proportions of two to five co-existing clones over time (2-3 months). Results for two markers, and two PCR primer pairs for one of those, matched very closely, supporting the efficacy of the method. Of the 54 infections, 67% displayed stable relative clonal proportions, with the others showing a shift in proportions, usually with one clone outpacing the others. Infections with rapidly increasing or slowly increasing parasitemia were stable, showing that all clones within these infections reproduced at the same rapid or slow rate. Replicate infections containing the same clones did not always reveal the same growth rate, final parasitemia or dominant clone; thus there was no clone effect for these life history measures. The rate of increase in parasitemia was not associated with stable versus unstable relative proportions, but infections with four to five clones were more likely to be unstable than those with two to three clones. This rare look into events in genetically complex Plasmodium infections suggests that parasite clones may be interacting in complex and unexpected ways.

  5. VEGF and LPS synergistically silence inflammatory response to Plasmodium berghei infection and protect against cerebral malaria

    PubMed Central

    Canavese, Miriam; Dottorini, Tania

    2015-01-01

    Malaria infection induces, alongside endothelial damage and obstruction hypoxia, a potent inflammatory response similar to that observed in other systemic diseases caused by bacteria and viruses. Accordingly, it is increasingly recognised that cerebral malaria (CM), the most severe and life threatening complication of Plasmodium falciparum infection, bears a number of similarities with sepsis, an often fatal condition associated with a misregulated inflammatory response triggered by systemic microbial infections. Using a Plasmodium berghei ANKA mouse model, histology, immunohistochemistry and gene expression analysis, we showed that lipopolysaccharide S (LPS), at doses that normally induce inflammation tolerance, protects P. berghei infected mice against experimental CM (ECM). Vascular endothelial growth factor (VEGF) preserved blood vessel integrity, and the combination with LPS resulted in a strong synergistic effect. Treated mice did not develop ECM, showed a prolonged survival and failed to develop a significant inflammatory response and splenomegaly in spite of normal parasite loads. The protective role of VEGF was further confirmed by the observation that the treatment of P. berghei infected C57BL/6 and Balb/c mice with the VEGF receptor inhibitor axitinib exacerbates cerebral pathology and aggravates the course of infection. Infected mice treated with VEGF and LPS showed an induction of the anti-inflammatory genes Nrf2 and HO-1 and a suppression to basal levels of the genes IFN-γ and TNF-α. These results provide the rationale for developing new therapeutic approaches against CM and shed new light on how the inflammatory process can be modulated in the presence of systemic infectious diseases. PMID:26392042

  6. Malaysian child infected with Plasmodium vivax via blood transfusion: a case report

    PubMed Central

    2013-01-01

    Malaria may be a serious complication of blood transfusion due to the asymptomatic persistence of parasites in some donors. This case report highlights the transfusion-transmitted malaria of Plasmodium vivax in a child diagnosed with germ cell tumour. This child had received blood transfusion from three donors and a week later started developing malaria like symptoms. Nested PCR and sequencing confirmed that one of the three donors was infected with P. vivax and this was transmitted to the 12-year-old child. To the best of the authors’ knowledge, this is the first reported transfusion-transmitted malaria case in Malaysia. PMID:24007496

  7. Plasmodium falciparum-infected mice: more than a tour de force.

    PubMed

    Moreno, Alicia; Pérignon, Jean Louis; Morosan, Serban; Mazier, Dominique; Benito, Agustin

    2007-06-01

    Up until recently, the relevance of Plasmodium falciparum-infected humanized mice for malaria studies has been questioned because of the low percentage of mice in which the parasite develops. Advances in the generation of new immunodeficient mouse strains combined with the use of protocols that modulate the innate immune defenses of mice have facilitated the harvesting of exoerythrocytic and intraerythrocytic stages of the parasite. These results renew the hope of working with P. falciparum in a laboratory animal and indicate that the next challenge (i.e. a complete parasite cycle in the same mouse, including transmission to mosquito) could be reached in the future.

  8. Plasmodium berghei infection in mice: effect of low-level ozone exposures

    SciTech Connect

    Moore, G.S.; Calabrese, E.J.; Molteni, K.H.

    1984-07-01

    Animal and human studies have accumulated that report erythrocyte effects from inhaled ozone (O/sub 3/). It was the purpose of this research to demonstrate the effects of O/sub 3/ exposure on the course of parasitemia in mice. A study was designed utilizing Plasmodium berghei, a murine malarial parasite host-specific for rodents, as the specific pathogen. The purpose of this project was to study mortality and percent parasitemia in the A/J mouse first infected with P. berghei and then exposed to low levels of ozone.

  9. Hepatic profile of Gallus gallus Linnaeus, 1758 experimentally infected by Plasmodium juxtanucleare Versiani & Gomes, 1941.

    PubMed

    Vashist, Usha; Falqueto, Aline Duarte; Lustrino, Danilo; Tunholi, Victor Menezes; Tunholi-Alves, Vinícius Menezes; dos Santos, Marcos Antônio José; D'Agosto, Marta; Massard, Carlos Luiz; Pinheiro, Jairo

    2011-02-10

    One of the species that causes avian malaria is Plasmodium juxtanucleare. It is commonly found in poultry, especially when the birds receive food free of coccidiostats. Since industrial and organic poultry breeding is increasing in the world and few studies have been conducted examining the clinical parameters of both healthy and infected birds, this work evaluated whether the infection caused by P. juxtanucleare in Gallus gallus provokes alterations in the birds' hepatic profile. We analyzed the activity of ALT and AST and carried out histological analyses of liver sections of infected fowls by intracelomic inoculation with infected blood from a donor fowl with a parasite load of around 7%. The infected birds' parasite load was evaluated during 45 days by means of blood smears. There was a positive correlation between the increase in parasite load and higher ALT activity in the infected fowls, but there was no significant variation of the AST activity between the control and infected groups, possibly because of the non-specificity of this enzyme as an indicator of hepatic lesion. The results show that infection caused by P. juxtanucleare in G. gallus provokes hepatic alterations, indicated by the increase in the ALT enzyme activity and by the inflammatory infiltrates found in the liver sections of the infected fowls.

  10. Parasite Sequestration in Plasmodium falciparum Malaria: Spleen and Antibody Modulation of Cytoadherence of Infected Erythrocytes

    NASA Astrophysics Data System (ADS)

    David, Peter H.; Hommel, Marcel; Miller, Louis H.; Udeinya, Iroka J.; Oligino, Lynette D.

    1983-08-01

    Sequestration, the adherence of infected erythrocytes containing late developmental stages of the parasite (trophozoites and schizonts) to the endothelium of capillaries and venules, is characteristic of Plasmodium falciparum infections. We have studied two host factors, the spleen and antibody, that influence sequestration of P. falciparum in the squirrel monkey. Sequestration of trophozoite/schizont-infected erythrocytes that occurs in intact animals is reduced in splenectomized animals; in vitro, when infected blood is incubated with monolayers of human melanoma cells, trophozoite/schizont-infected erythrocytes from intact animals but not from splenectomized animals bind to the melanoma cells. The switch in cytoadherence characteristics of the infected erythrocytes from nonbinding to binding occurs with a cloned parasite. Immune serum can inhibit and reverse in vitro binding to melanoma cells of infected erythrocytes from intact animals. Similarly, antibody can reverse in vivo sequestration as shown by the appearance of trophozoite/schizont-infected erythrocytes in the peripheral blood of an intact animal after inoculation with immune serum. These results indicate that the spleen modulates the expression of parasite alterations of the infected erythrocyte membrane responsible for sequestration and suggest that the prevention and reversal of sequestration could be one of the effector mechanisms involved in antibody-mediated protection against P. falciparum malaria.

  11. Mesangial proliferative glomerulonephritis in murine malaria parasite, Plasmodium chabaudi AS, infected NC mice.

    PubMed

    Yashima, Akihito; Mizuno, Masashi; Yuzawa, Yukio; Shimada, Koki; Suzuki, Norihiko; Tawada, Hideo; Sato, Waichi; Tsuboi, Naotake; Maruyama, Shoichi; Ito, Yasuhiko; Matsuo, Seiichi; Ohno, Tamio

    2017-08-01

    Malaria is an important tropical disease and has remained a serious health problem in many countries. One of the critical complications of malarial infection is renal injury, such as acute renal failure and chronic glomerulopathy. Few animal models of nephropathy related to malarial infection have been reported. Therefore, we developed and investigated a novel malarial nephropathy model in mice infected by murine malaria parasites. NC mice and C57BL/6J mice were infected with Ttwo different murine malaria parasites, Plasmodium (P.) chabaudi AS and P. yoelii 17X. After the infection, renal pathology and blood and urinary biochemistry were analyzed. NC mice infected by the murine malaria parasite P. chabaudi AS, but not P. yoelii 17X, developed mesangial proliferative glomerulonephritis with endothelial damage, and decreased serum albumin concentration and increased proteinuria. These pathological changes were accompanied by deposition of immunoglobulin G and complement component 3, mainly in the mesangium until day 4 and in the mesangium and glomerular capillaries from day 8. On day 21, renal pathology developed to focal segmental sclerosis according to light microscopy. In C57BL/6J mice, renal injuries were not observed from either parasite infection. The clinical and pathological features of P. chabaudi AS infection in NC mice might be similar to quartan malarial nephropathy resulting from human malaria parasite P. malariae infection. The NC mouse model might therefore be useful in analyzing the underlying mechanisms and developing therapeutic approaches to malaria-related nephropathy.

  12. Exacerbation of autoimmune neuro-inflammation in mice cured from blood-stage Plasmodium berghei infection.

    PubMed

    Thomé, Rodolfo; Bombeiro, André Luis; Issayama, Luidy Kazuo; Rapôso, Catarina; Lopes, Stefanie Costa Pinto; da Costa, Thiago Alves; Di Gangi, Rosária; Ferreira, Isadora Tassinari; Longhini, Ana Leda Figueiredo; Oliveira, Alexandre Leite Rodrigues; da Cruz Höfling, Maria Alice; Costa, Fábio Trindade Maranhão; Verinaud, Liana

    2014-01-01

    The thymus plays an important role shaping the T cell repertoire in the periphery, partly, through the elimination of inflammatory auto-reactive cells. It has been shown that, during Plasmodium berghei infection, the thymus is rendered atrophic by the premature egress of CD4+CD8+ double-positive (DP) T cells to the periphery. To investigate whether autoimmune diseases are affected after Plasmodium berghei NK65 infection, we immunized C57BL/6 mice, which was previously infected with P. berghei NK65 and treated with chloroquine (CQ), with MOG35-55 peptide and the clinical course of Experimental Autoimmune Encephalomyelitis (EAE) was evaluated. Our results showed that NK65+CQ+EAE mice developed a more severe disease than control EAE mice. The same pattern of disease severity was observed in MOG35-55-immunized mice after adoptive transfer of P. berghei-elicited splenic DP-T cells. The higher frequency of IL-17+- and IFN-γ+-producing DP lymphocytes in the Central Nervous System of these mice suggests that immature lymphocytes contribute to disease worsening. To our knowledge, this is the first study to integrate the possible relationship between malaria and multiple sclerosis through the contribution of the thymus. Notwithstanding, further studies must be conducted to assert the relevance of malaria-induced thymic atrophy in the susceptibility and clinical course of other inflammatory autoimmune diseases.

  13. Flow cytometric enumeration of Plasmodium berghei-infected red blood cells stained with SYBR Green I.

    PubMed

    Somsak, Voravuth; Srichairatanakool, Somdet; Yuthavong, Yongyuth; Kamchonwongpaisan, Sumalee; Uthaipibull, Chairat

    2012-04-01

    High-throughput methods for evaluation of in vivo efficacy of candidate compounds against Plasmodium parasites are necessary during the antimalarial drug development process. It is essential that enumeration of parasitemia in the infected blood from experimental host animals is accurate and reliable. Flow cytometric enumeration of parasitized cells stained with fluorescent dye is a rapid alternative method to conventional microscopic counting. In this study, a protocol for flow cytometric enumeration of rodent malaria parasite Plasmodium berghei-infected red blood cells (RBC) stained with SYBR Green I was developed. The optimal concentration of SYBR Green I used to stain infected RBC was 4× for 30 min. This SYBR Green I staining protocol in combination with the bi-dimensional FL-1(530)/FL-3(620) detection method accurately detects parasitemia above 0.02%. The dye is stable during the prolonged incubation period necessary for accurate enumeration of parasitemia, with no loss of fluorescent signal over a period of hours. This protocol was validated in an antimalarial assay and the result was comparable to that obtained from conventional microscopic counting. The SYBR Green I flow cytometric protocol is thus a rapid and precise tool for high-throughput in vivo antimalarial drug screening.

  14. Status of ammonia, glutamate, lactate and pyruvate during Plasmodium yoelii infection and pyrimethamine treatment in mice.

    PubMed

    Agarwal, A; Tripathi, L M; Pandey, V C

    1997-09-01

    Ammonia, lactate, glutamate and pyruvate levels in blood, liver, brain, spleen and kidney were determined during Plasmodium yoelii infection and pyrimethamine treatment in mice. Ammonia and lactate levels showed significant increase with rise in parasitaemia except in spleen where decrease in the lactate levels was observed. The glutamate level displayed a marked decrease in blood, liver and splenic tissues, whereas, significant increase in glutamate level in kidney was observed, although its level in cerebral tissue remained unaltered. The pyruvate level in blood and liver showed a noticeable decrease but brain, spleen and kidney registered an elevation of the same due to the parasitic infection. Pyrimethamine (oral) treatment (10 mg/kg body weight) to infected mice (5-10%) for four days brought back the altered levels of the above cellular constituents in different tissues to normal, a week after cessation of drug treatment.

  15. Malaria transmission-blocking immunity induced by natural infections of Plasmodium vivax in humans.

    PubMed Central

    Mendis, K N; Munesinghe, Y D; de Silva, Y N; Keragalla, I; Carter, R

    1987-01-01

    Immunity to malarial infections in human populations is known to affect the development of the asexual blood stages of the parasites in the human host and to be capable of conferring significant protection against morbidity and mortality due to the disease. In this study we show that during acute infection with Plasmodium vivax malaria, one of the two main malarial pathogens of humans, most individuals also develop immunity that suppresses the infectivity of the sexual stages of the parasite to mosquitoes. The immunity is antibody mediated and is directed against the parasites in the mosquito midgut shortly after ingestion of blood by a mosquito. This immunity could be expected to have significant effects on the natural transmission of P. vivax malaria. Images PMID:2879793

  16. NF135.C10: A New Plasmodium falciparum Clone for Controlled Human Malaria Infections

    PubMed Central

    Teirlinck, Anne C.; Roestenberg, Meta; van de Vegte-Bolmer, Marga; Scholzen, Anja; Heinrichs, Moniek J. L.; Siebelink-Stoter, Rianne; Graumans, Wouter; van Gemert, Geert-Jan; Teelen, Karina; Vos, Martijn W.; Nganou-Makamdop, Krystelle; Borrmann, Steffen; Rozier, Yolanda P. A.; Erkens, Marianne A. A.; Luty, Adrian J. F.; Hermsen, Cornelus C.; Sim, B. Kim Lee; van Lieshout, Lisette; Hoffman, Stephen L.; Visser, Leo G.; Sauerwein, Robert W.

    2013-01-01

    We established a new field clone of Plasmodium falciparum for use in controlled human malaria infections and vaccine studies to complement the current small portfolio of P. falciparum strains, primarily based on NF54. The Cambodian clone NF135.C10 consistently produced gametocytes and generated substantial numbers of sporozoites in Anopheles mosquitoes and diverged from NF54 parasites by genetic markers. In a controlled human malaria infection trial, 3 of 5 volunteers challenged by mosquitoes infected with NF135.C10 and 4 of 5 challenged with NF54 developed parasitemia as detected with microscopy. The 2 strains induced similar clinical signs and symptoms as well as cellular immunological responses. Clinical Trials Registration NCT01002833. PMID:23186785

  17. Biomarkers of Plasmodium falciparum Infection during Pregnancy in Women Living in Northeastern Tanzania

    PubMed Central

    Boström, Stéphanie; Ibitokou, Samad; Oesterholt, Mayke; Schmiegelow, Christentze; Persson, Jan-Olov; Minja, Daniel; Lusingu, John; Lemnge, Martha; Fievet, Nadine; Deloron, Philippe; Luty, Adrian J. F.; Troye-Blomberg, Marita

    2012-01-01

    In pregnant women, Plasmodium falciparum infections are an important cause of maternal morbidity as well as fetal and neonatal mortality. Erythrocytes infected by these malaria-causing parasites accumulate through adhesive interactions in placental intervillous spaces, thus evading detection in peripheral blood smears. Sequestered infected erythrocytes induce inflammation, offering the possibility of detecting inflammatory mediators in peripheral blood that could act as biomarkers of placental infection. In a longitudinal, prospective study in Tanzania, we quantified a range of different cytokines, chemokines and angiogenic factors in peripheral plasma samples, taken on multiple sequential occasions during pregnancy up to and including delivery, from P. falciparum-infected women and matched uninfected controls. The results show that during healthy, uninfected pregnancies the levels of most of the panel of molecules we measured were largely unchanged except at delivery. In women with P. falciparum, however, both comparative and longitudinal assessments consistently showed that the levels of IL-10 and IP-10 increased significantly whilst that of RANTES decreased significantly, regardless of gestational age at the time the infection was detected. ROC curve analysis indicated that a combination of increased IL-10 and IP-10 levels and decreased RANTES levels might be predictive of P. falciparum infections. In conclusion, our data suggest that host biomarkers in peripheral blood may represent useful diagnostic markers of P. falciparum infection during pregnancy, but placental histology results would need to be included to verify these findings. PMID:23155405

  18. Distribution and Risk Factors for Plasmodium and Helminth Co-infections: A Cross-Sectional Survey among Children in Bagamoyo District, Coastal Region of Tanzania

    PubMed Central

    Salim, Nahya; Knopp, Stefanie; Lweno, Omar; Abdul, Ummi; Mohamed, Ali; Schindler, Tobias; Rothen, Julian; Masimba, John; Kwaba, Denis; Mohammed, Alisa S.; Althaus, Fabrice; Abdulla, Salim; Tanner, Marcel; Daubenberger, Claudia; Genton, Blaise

    2015-01-01

    Background Plasmodium and soil transmitted helminth infections (STH) are a major public health problem, particularly among children. There are conflicting findings on potential association between these two parasites. This study investigated the Plasmodium and helminth co-infections among children aged 2 months to 9 years living in Bagamoyo district, coastal region of Tanzania. Methods A community-based cross-sectional survey was conducted among 1033 children. Stool, urine and blood samples were examined using a broad set of quality controlled diagnostic methods for common STH (Ascaris lumbricoides, hookworm, Strongyloides stercoralis, Enterobius vermicularis, Trichuris trichura), schistosoma species and Wuchereria bancrofti. Blood slides and malaria rapid diagnostic tests (mRDTs) were utilized for Plasmodium diagnosis. Results Out of 992 children analyzed, the prevalence of Plasmodium infection was 13% (130/992), helminth 28.5% (283/992); 5% (50/992) had co-infection with Plasmodium and helminth. The prevalence rate of Plasmodium, specific STH and co-infections increased significantly with age (p < 0.001), with older children mostly affected except for S. stercoralis monoinfection and co-infections. Spatial variations of co-infection prevalence were observed between and within villages. There was a trend for STH infections to be associated with Plasmodium infection [OR adjusted for age group 1.4, 95% CI (1.0–2.1)], which was more marked for S. stercoralis (OR = 2.2, 95% CI (1.1–4.3). Age and not schooling were risk factors for Plasmodium and STH co-infection. Conclusion The findings suggest that STH and Plasmodium infections tend to occur in the same children, with increasing prevalence of co-infection with age. This calls for an integrated approach such as using mass chemotherapy with dual effect (e.g., ivermectin) coupled with improved housing, sanitation and hygiene for the control of both parasitic infections. PMID:25837022

  19. Distribution and risk factors for Plasmodium and helminth co-infections: a cross-sectional survey among children in Bagamoyo district, coastal region of Tanzania.

    PubMed

    Salim, Nahya; Knopp, Stefanie; Lweno, Omar; Abdul, Ummi; Mohamed, Ali; Schindler, Tobias; Rothen, Julian; Masimba, John; Kwaba, Denis; Mohammed, Alisa S; Althaus, Fabrice; Abdulla, Salim; Tanner, Marcel; Daubenberger, Claudia; Genton, Blaise

    2015-04-01

    Plasmodium and soil transmitted helminth infections (STH) are a major public health problem, particularly among children. There are conflicting findings on potential association between these two parasites. This study investigated the Plasmodium and helminth co-infections among children aged 2 months to 9 years living in Bagamoyo district, coastal region of Tanzania. A community-based cross-sectional survey was conducted among 1033 children. Stool, urine and blood samples were examined using a broad set of quality controlled diagnostic methods for common STH (Ascaris lumbricoides, hookworm, Strongyloides stercoralis, Enterobius vermicularis, Trichuris trichura), schistosoma species and Wuchereria bancrofti. Blood slides and malaria rapid diagnostic tests (mRDTs) were utilized for Plasmodium diagnosis. Out of 992 children analyzed, the prevalence of Plasmodium infection was 13% (130/992), helminth 28.5% (283/992); 5% (50/992) had co-infection with Plasmodium and helminth. The prevalence rate of Plasmodium, specific STH and co-infections increased significantly with age (p < 0.001), with older children mostly affected except for S. stercoralis monoinfection and co-infections. Spatial variations of co-infection prevalence were observed between and within villages. There was a trend for STH infections to be associated with Plasmodium infection [OR adjusted for age group 1.4, 95% CI (1.0-2.1)], which was more marked for S. stercoralis (OR = 2.2, 95% CI (1.1-4.3). Age and not schooling were risk factors for Plasmodium and STH co-infection. The findings suggest that STH and Plasmodium infections tend to occur in the same children, with increasing prevalence of co-infection with age. This calls for an integrated approach such as using mass chemotherapy with dual effect (e.g., ivermectin) coupled with improved housing, sanitation and hygiene for the control of both parasitic infections.

  20. Interrogation of infected hepatocyte signaling reveals that suppression of host p53 is critical for Plasmodium liver stage infection

    PubMed Central

    Kaushansky, Alexis; Ye, Albert S.; Austin, Laura S.; Mikolajczak, Sebastian A.; Vaughan, Ashley M.; Camargo, Nelly; Metzger, Peter G.; Douglass, Alyse N.; MacBeath, Gavin; Kappe, Stefan H.I.

    2013-01-01

    Summary Plasmodium parasites infect the liver and replicate inside hepatocytes before they invade erythrocytes and trigger clinical malaria. Analysis of host signaling pathways affected by liver stage infection could provide critical insights into host-pathogen interactions and reveal targets for intervention. Using protein lysate microarrays we found that Plasmodium yoelii rodent malaria parasites perturb hepatocyte regulatory pathways involved in cell survival, proliferation and autophagy. Notably, the pro-death protein p53 was substantially decreased in infected hepatocytes, suggesting it could be targeted by the parasite to foster survival. Indeed, mice that express increased levels of p53 showed reduced liver stage parasite burden whereas p53 knockout mice suffered increased liver stage burden. Furthermore, boosting p53 levels using the small molecule Nutlin-3 dramatically reduced liver stage burden in vitro and in vivo. We conclude that perturbation of the hepatocyte p53 pathway critically impacts parasite survival. Thus, host pathways might constitute potential targets for host-based antimalarial prophylaxis. PMID:23478020

  1. Influence of host iron status on Plasmodium falciparum infection

    PubMed Central

    Clark, Martha A.; Goheen, Morgan M.; Cerami, Carla

    2014-01-01

    Iron deficiency affects one quarter of the world's population and causes significant morbidity, including detrimental effects on immune function and cognitive development. Accordingly, the World Health Organization (WHO) recommends routine iron supplementation in children and adults in areas with a high prevalence of iron deficiency. However, a large body of clinical and epidemiological evidence has accumulated which clearly demonstrates that host iron deficiency is protective against falciparum malaria and that host iron supplementation may increase the risk of malaria. Although many effective antimalarial treatments and preventive measures are available, malaria remains a significant public health problem, in part because the mechanisms of malaria pathogenesis remain obscured by the complexity of the relationships that exist between parasite virulence factors, host susceptibility traits, and the immune responses that modulate disease. Here we review (i) the clinical and epidemiological data that describes the relationship between host iron status and malaria infection and (ii) the current understanding of the biological basis for these clinical and epidemiological observations. PMID:24834053

  2. Infection Intensity-Dependent Responses of Anopheles gambiae to the African Malaria Parasite Plasmodium falciparum ▿ †

    PubMed Central

    Mendes, Antonio M.; Awono-Ambene, Parfait H.; Nsango, Sandrine E.; Cohuet, Anna; Fontenille, Didier; Kafatos, Fotis C.; Christophides, George K.; Morlais, Isabelle; Vlachou, Dina

    2011-01-01

    Malaria remains a devastating disease despite efforts at control and prevention. Extensive studies using mostly rodent infection models reveal that successful Plasmodium parasite transmission by the African mosquito vector Anopheles gambiae depends on finely tuned vector-parasite interactions. Here we investigate the transcriptional response of A. gambiae to geographically related Plasmodium falciparum populations at various infection intensities and different infection stages. These responses are compared with those of mosquitoes infected with the rodent parasite Plasmodium berghei. We demonstrate that mosquito responses are largely dependent on the intensity of infection. A major transcriptional suppression of genes involved in the regulation of midgut homeostasis is detected in low-intensity P. falciparum infections, the most common type of infection in Africa. Importantly, genes transcriptionally induced during these infections tend to be phylogenetically unique to A. gambiae. These data suggest that coadaptation between vectors and parasites may act to minimize the impact of infection on mosquito fitness by selectively suppressing specific functional classes of genes. RNA interference (RNAi)-mediated gene silencing provides initial evidence for important roles of the mosquito G protein-coupled receptors (GPCRs) in controlling infection intensity-dependent antiparasitic responses. PMID:21844236

  3. Housing conditions and Plasmodium falciparum infection: protective effect of iron-sheet roofed houses.

    PubMed

    Yé, Yazoumé; Hoshen, Moshe; Louis, Valérie; Séraphin, Simboro; Traoré, Issouf; Sauerborn, Rainer

    2006-02-01

    Identification and better understanding of potential risk factors for malaria are important for targeted and cost-effective health interventions. Housing conditions have been suggested as one of the potential risk factors. This study aims to further investigate this risk factor, and is focused on the effect of the type of roof on Plasmodium falciparum infection among children below five years in the North West of Burkina Faso. In a cross-sectional study design, 661 children aged six to 60 months were randomly selected from three rural and one semi-urban site at the end of the rainy season (November 2003). The children were screened for fever and tested for Plasmodium falciparum infection. In addition, data on bed net use and house characteristics was collected from the household were each child lived. Using adjusted odds ratios, children living in house roofed with iron-sheet were compared with those in house with mud or grass roof. Overall P. falciparum infection prevalence was 22.8 % with a significant variation between (Chi-square, p < 0.0001). The prevalence in Cissé (33.3 %) and Goni (30.6 %) were twice times more than in Nouna (15.2 %) and Kodougou (13.2 %). After adjusting for age, sex, use of bed net and housing conditions, children living in houses with mud roofs had significantly higher risk of getting P. falciparum infection compared to those living in iron-sheet roofed houses (Odds Ratio 2.6; 95% Confidence Interval, 1.4-4.7). These results suggest that house characteristics should be taken into consideration when designing health intervention against P. falciparum infection and particular attention should be paid to children living in houses with mud roofs.

  4. Perforin-like protein PPLP4 is crucial for mosquito midgut infection by Plasmodium falciparum.

    PubMed

    Wirth, Christine C; Bennink, Sandra; Scheuermayer, Matthias; Fischer, Rainer; Pradel, Gabriele

    2015-06-01

    The genomes of Plasmodium parasites encode for five perforin-like proteins, PPLP1-5, and four of them have previously been demonstrated to be involved in disruption of host cell barriers. We now show that the fifth perforin, PPLP4, is crucial for infection of the mosquito vector by Plasmodium falciparum parasites. PPLP4 is expressed in the blood and mosquito midgut stages in granular structures. In gametocytes, PPLP4 expression is specific to the female gender, while ookinetes show a PPLP4 localization at the apical pole. Gene disruption of pplp4 results in no phenotypical change during blood stage replication, gametocyte development or gametogenesis, while mosquitoes fed with PPLP4-deficient gametocytes display a severe reduction in oocyst numbers, and an accumulation of ookinetes in the mosquito midguts was observed. In conclusion, we propose an essential role for PPLP4 in infection of the mosquito midgut, presumably by mediating ookinete traversal through the midgut epithelium. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  5. Angiotensin II Moderately Decreases Plasmodium Infection and Experimental Cerebral Malaria in Mice.

    PubMed

    Gallego-Delgado, Julio; Baravian, Charlotte; Edagha, Innocent; Ty, Maureen C; Ruiz-Ortega, Marta; Xu, Wenyue; Rodriguez, Ana

    2015-01-01

    Angiotensin II, a peptide hormone that regulates blood pressure, has been proposed as a protective factor against cerebral malaria based on a genetic analysis. In vitro studies have documented an inhibitory effect of angiotensin II on Plasmodium growth, while studies using chemical inhibitors of angiotensin II in mice showed protection against experimental cerebral malaria but not major effects on parasite growth. To determine whether the level of angiotensin II affects Plasmodium growth and/or disease outcome in malaria, elevated levels of angiotensin II were induced in mice by intradermal implantation of osmotic mini-pumps providing constant release of this hormone. Mice were then infected with P. berghei and monitored for parasitemia and incidence of cerebral malaria. Mice infused with angiotensin II showed decreased parasitemia seven days after infection. The development of experimental cerebral malaria was delayed and a moderate increase in survival was observed in mice with elevated angiotensin II, as confirmed by decreased number of cerebral hemorrhages compared to controls. The results presented here show for the first time the effect of elevated levels of angiotensin II in an in vivo model of malaria. The decreased pathogenesis observed in mice complements a previous human genetic study, reinforcing the hypothesis of a beneficial effect of angiotensin II in malaria.

  6. Angiotensin II Moderately Decreases Plasmodium Infection and Experimental Cerebral Malaria in Mice

    PubMed Central

    Gallego-Delgado, Julio; Baravian, Charlotte; Edagha, Innocent; Ty, Maureen C.; Ruiz-Ortega, Marta; Xu, Wenyue; Rodriguez, Ana

    2015-01-01

    Angiotensin II, a peptide hormone that regulates blood pressure, has been proposed as a protective factor against cerebral malaria based on a genetic analysis. In vitro studies have documented an inhibitory effect of angiotensin II on Plasmodium growth, while studies using chemical inhibitors of angiotensin II in mice showed protection against experimental cerebral malaria but not major effects on parasite growth. To determine whether the level of angiotensin II affects Plasmodium growth and/or disease outcome in malaria, elevated levels of angiotensin II were induced in mice by intradermal implantation of osmotic mini-pumps providing constant release of this hormone. Mice were then infected with P. berghei and monitored for parasitemia and incidence of cerebral malaria. Mice infused with angiotensin II showed decreased parasitemia seven days after infection. The development of experimental cerebral malaria was delayed and a moderate increase in survival was observed in mice with elevated angiotensin II, as confirmed by decreased number of cerebral hemorrhages compared to controls. The results presented here show for the first time the effect of elevated levels of angiotensin II in an in vivo model of malaria. The decreased pathogenesis observed in mice complements a previous human genetic study, reinforcing the hypothesis of a beneficial effect of angiotensin II in malaria. PMID:26376293

  7. The development and persistence of phanerozoites in experimental infections of Plasmodium sasai.

    PubMed

    Telford, S R

    1998-03-01

    Phanerozoites of Plasmodium sasai parasitised virtually all tissues of Takydromus tachydromoides infected by inoculation of blood, and persisted until each lizard died, 2-296 days postinoculation. At 4 days postinoculation, phanerozoites were larger than at 2 and 6 days; many were observed rupturing, suggesing a maturation time of approximately 4 days. The proliferation of phanerozoites decreased after 2 months postinoculation, but small phanerozoites were still present at 296 days. A few encysted phanerozoites (chronozoites) appeared at 2 days postinoculation, but from 75 days comprised over half of parasites present in most tissues. Some differences in mean size and shape were evident among various organs. Phanerozoites occurred in connective tissue and endothelium in all organs, but were most plentiful in the heart in every infection, often occurring in clusters of > 30 schizonts, with up to 105 found in single sections at 4 days. Phanerozoites did not parasitise reticular cells of the spleen and bone marrow, in contrast to Plasmodium mexicanum as described in unnatural host species. Little difference was seen between two strains of P. sasai in its natural host T. tachydromoides and a strain isolated from Takydromus smaragdinus.

  8. Plasmodium falciparum proteins involved in cytoadherence of infected erythrocytes to chemokine CX3CL1

    PubMed Central

    Hermand, Patricia; Cicéron, Liliane; Pionneau, Cédric; Vaquero, Catherine; Combadière, Christophe; Deterre, Philippe

    2016-01-01

    Malaria caused by Plasmodium falciparum is associated with cytoadherence of infected red blood cells (iRBC) to endothelial cells. Numerous host molecules have been involved in cytoadherence, including the adhesive chemokine CX3CL1. Most of the identified parasite ligands are from the multigenic and hypervariable Plasmodium falciparum Erythrocyte Membrane Protein 1 (PfEMP1) family which makes them poor targets for the development of a broadly protective vaccine. Using proteomics, we have identified two 25-kDa parasite proteins with adhesive properties for CX3CL1, called CBP for CX3CL1 Binding Proteins. CBPs are coded by single-copy genes with little polymorphic variation and no homology with other P. falciparum gene products. Specific antibodies raised against epitopes from the predicted extracellular domains of each CBP efficiently stain the surface of RBC infected with trophozoites or schizonts, which is a strong indication of CBP expression at the surface of iRBC. These anti-CBP antibodies partially neutralize iRBC adherence to CX3CL1. This adherence is similarly inhibited in the presence of peptides from the CBP extracellular domains, while irrelevant peptides had no such effect. CBP1 and CBP2 are new P. falciparum ligands for the human chemokine CX3CL1. The identification of this non-polymorphic P. falciparum factors provides a new avenue for innovative vaccination approaches. PMID:27653778

  9. Host cell remodeling by pathogens: the exomembrane system in Plasmodium-infected erythrocytes

    PubMed Central

    Sherling, Emma S.; van Ooij, Christiaan

    2016-01-01

    Malaria is caused by infection of erythrocytes by parasites of the genus Plasmodium. To survive inside erythrocytes, these parasites induce sweeping changes within the host cell, one of the most dramatic of which is the formation of multiple membranous compartments, collectively referred to as the exomembrane system. As an uninfected mammalian erythrocyte is devoid of internal membranes, the parasite must be the force and the source behind the formation of these compartments. Even though the first evidence of the presence these of internal compartments was obtained over a century ago, their functions remain mostly unclear, and in some cases completely unknown, and the mechanisms underlying their formation are still mysterious. In this review, we provide an overview of the different parts of the exomembrane system, describing the parasitophorous vacuole, the tubovesicular network, Maurer's clefts, the caveola-vesicle complex, J dots and other mobile compartments, and the small vesicles that have been observed in Plasmodium-infected cells. Finally, we combine the data into a simplified view of the exomembrane system and its relation to the alterations of the host erythrocyte. PMID:27587718

  10. Plasmodium (Bennettinia) juxtanucleare infection in a captive white eared-pheasant (Crossoptilon crossoptilon) at a Japanese zoo.

    PubMed

    Murata, Koichi; Nii, Ryosuke; Sasaki, Emi; Ishikawa, Satoshi; Sato, Yukita; Sawabe, Kyoko; Tsuda, Yoshio; Matsumoto, Rei; Suda, Akemi; Ueda, Miya

    2008-02-01

    An adult male white eared-pheasant (Crossoptilon crossoptilon) at a Japanese zoo exhibited lethargy and emaciation. Microscopic examination of a blood smear revealed a haemosporidian parasitic infection. Based on the morphological characteristics and molecular analysis of the parasite, it was identified as Plasmodium (Bennettinia) juxtanucleare. This is the first report of P. juxtanucleare infection in bird species belonging to the genus Crossoptilon. Caution against avian malaria infection is required for the conservation of endangered bird species in zoos.

  11. Leukocyte profiles for western fence lizards, Sceloporus occidentalis, naturally infected by the malaria parasite Plasmodium mexicanum.

    PubMed

    Motz, Victoria L; Lewis, William D; Vardo-Zalik, Anne M

    2014-10-01

    Plasmodium mexicanum is a malaria parasite that naturally infects the western fence lizard, Sceloporus occidentalis , in northern California. We set out to determine whether lizards naturally infected with this malaria parasite have different leukocyte profiles, indicating an immune response to infection. We used 29 naturally infected western fence lizards paired with uninfected lizards based on sex, snout-to-vent length, tail status, and the presence-absence of ectoparasites such as ticks and mites, as well as the presence-absence of another hemoparasite, Schellackia occidentalis. Complete white blood cell (WBC) counts were conducted on blood smears stained with Giemsa, and the proportion of granulocytes per microliter of blood was estimated using the Avian Leukopet method. The abundance of each WBC class (lymphocytes, monocytes, heterophils, eosinophils, and basophils) in infected and uninfected lizards was compared to determine whether leukocyte densities varied with infection status. We found that the numbers of WBCs and lymphocytes per microliter of blood significantly differed (P < 0.05) between the 2 groups for females but not for males, whereas parasitemia was significantly correlated with lymphocyte counts for males, but not for females. This study supports the theory that infection with P. mexicanum stimulates the lizard's immune response to increase the levels of circulating WBCs, but what effect this has on the biology of the parasite remains unclear.

  12. Plasmodium falciparum Mating Patterns and Mosquito Infectivity of Natural Isolates of Gametocytes

    PubMed Central

    Morlais, Isabelle; Nsango, Sandrine E.; Toussile, Wilson; Abate, Luc; Annan, Zeinab; Tchioffo, Majoline T.; Cohuet, Anna; Awono-Ambene, Parfait H.; Fontenille, Didier; Rousset, François; Berry, Antoine

    2015-01-01

    Plasmodium falciparum infections in malaria endemic areas often harbor multiple clones of parasites. However, the transmission success of the different genotypes within the mosquito vector has remained elusive so far. The genetic diversity of malaria parasites was measured by using microsatellite markers in gametocyte isolates from 125 asymptomatic carriers. For a subset of 49 carriers, the dynamics of co-infecting genotypes was followed until their development within salivary glands. Also, individual oocysts from midguts infected with blood from 9 donors were genotyped to assess mating patterns. Multiplicity of infection (MOI) was high both in gametocyte isolates and sporozoite populations, reaching up to 10 genotypes. Gametocyte isolates with multiple genotypes gave rise to lower infection prevalence and intensity. Fluctuations of genotype number occurred during the development within the mosquito and sub-patent genotypes, not detected in gametocyte isolates, were identified in the vector salivary glands. The inbreeding coefficient Fis was positively correlated to the oocyst loads, suggesting that P. falciparum parasites use different reproductive strategies according to the genotypes present in the gametocyte isolate. The number of parasite clones within an infection affects the transmission success and the mosquito has an important role in maintaining P. falciparum genetic diversity. Our results emphasize the crucial importance of discriminating between the different genotypes within an infection when studying the A. gambiae natural resistance to P. falciparum, and the need to monitor parasite diversity in areas where malaria control interventions are implemented. PMID:25875840

  13. PCR diagnostics underestimate the prevalence of avian malaria (Plasmodium relictum) in experimentally-infected passerines.

    PubMed

    Jarvi, Susan I; Schultz, Jeffrey J; Atkinson, Carter T

    2002-02-01

    Several polymerase chain reaction (PCR)-based methods have recently been developed for diagnosing malarial infections in both birds and reptiles, but a critical evaluation of their sensitivity in experimentally-infected hosts has not been done. This study compares the sensitivity of several PCR-based methods for diagnosing avian malaria (Plasmodium relictum) in captive Hawaiian honeycreepers using microscopy and a recently developed immunoblotting technique. Sequential blood samples were collected over periods of up to 4.4 yr after experimental infection and rechallenge to determine both the duration and detectability of chronic infections. Two new nested PCR approaches for detecting circulating parasites based on P. relictum 18S rRNA genes and the thrombospondin-related anonymous protein (TRAP) gene are described. The blood smear and the PCR tests were less sensitive than serological methods for detecting chronic malarial infections. Individually, none of the diagnostic methods was 100% accurate in detecting subpatent infections, although serological methods were significantly more sensitive (97%) than either nested PCR (61-84%) or microscopy (27%). Circulating parasites in chronically infected birds either disappear completely from circulation or to drop to intensities below detectability by nested PCR. Thus, the use of PCR as a sole means of detection of circulating parasites may significantly underestimate true prevalence.

  14. PCR diagnostics underestimate the prevalence of avian malaria (Plasmodium relictum) in experimentally-infected passerines

    USGS Publications Warehouse

    Jarvi, Susan I.; Schultz, Jeffrey J.; Atkinson, Carter T.

    2002-01-01

    Several polymerase chain reaction (PCR)-based methods have recently been developed for diagnosing malarial infections in both birds and reptiles, but a critical evaluation of their sensitivity in experimentally-infected hosts has not been done. This study compares the sensitivity of several PCR-based methods for diagnosing avian malaria (Plasmodium relictum) in captive Hawaiian honeycreepers using microscopy and a recently developed immunoblotting technique. Sequential blood samples were collected over periods of up to 4.4 yr after experimental infection and rechallenge to determine both the duration and detectability of chronic infections. Two new nested PCR approaches for detecting circulating parasites based on P. relictum 18S rRNA genes and the thrombospondin-related anonymous protein (TRAP) gene are described. The blood smear and the PCR tests were less sensitive than serological methods for detecting chronic malarial infections. Individually, none of the diagnostic methods was 100% accurate in detecting subpatent infections, although serological methods were significantly more sensitive (97%) than either nested PCR (61–84%) or microscopy (27%). Circulating parasites in chronically infected birds either disappear completely from circulation or to drop to intensities below detectability by nested PCR. Thus, the use of PCR as a sole means of detection of circulating parasites may significantly underestimate true prevalence.

  15. Changing trends in prevalence of different Plasmodium species with dominance of Plasmodium falciparum malaria infection in Aligarh (India).

    PubMed

    Khan, Haris M; Shujatullah, Fatima; Ashfaq, Mohammad; Raza, Adil

    2011-01-01

    To determine the prevalence of malaria in Aligarh and analyze species dominance in different years over a decade. Diagnosis of malaria was done using microscopy as gold standard, rapid antigen detection assays and quantitative buffy coat (QBC) assays. Giemsa stained blood smear examination was done, thick and thin films were examined for presence of different Plasmodium spp. Rapid antigen detection assays employing detection of HRP-2 and parasite lactate dehydrogenase antigen (pLDH) by immunochromatography was done in patients whose blood smear found to be negative by conventional Giemsa slide examination. QBC was done in cases where there is strong clinical suspicion of malaria with blood smear negative, in patients with chronic malaria, splenomegaly, or in those patients who had inadequate treatment and for post-treatment follow up. Plasmodium vivax and Plasmodium falciparum were only species detected in our hospital. Overall prevalence of malaria in Aligarh was found to be 8.8%. The maximum prevalence of 20.1% was observed in year 2008 and lowest 2.3% in 2002. High prevalence of malaria is observed in this part of country with dominance of both species particularly Plasmodium falciparum should be monitored and factors accounting for occurrence should be studied to employ effective control measures. Copyright © 2011 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

  16. Plasmodium vivax infection: a major determinant of severe anaemia in infancy.

    PubMed

    Kenangalem, Enny; Karyana, Muhammad; Burdarm, Lenny; Yeung, Shunmay; Simpson, Julie A; Tjitra, Emiliana; Anstey, Nicholas M; Poespoprodjo, Jeanne Rini; Price, Ric N; Douglas, Nicholas M

    2016-06-16

    Most malarious countries outside of Africa are co-endemic for Plasmodium falciparum and Plasmodium vivax. The comparative burden of anaemia in the community caused by these two species is incompletely characterized. A three-stage, cross-sectional, community survey was used to determine the proportion of moderate or severe anaemia (haemoglobin <7 g/dL) attributable to patent P. vivax, P. falciparum and mixed parasitaemia in Papua, Indonesia. Adjusted population-attributable fractions were calculated from multivariable logistic regression models. Eight hundred and twenty-five households were surveyed with a total of 5255 occupants, 3890 (74 %) of whom were present and provided a blood sample. Plasmodium falciparum parasitaemia was present in 8.1 % (n = 315) of participants, P. vivax in 6.4 % (n = 250) and mixed infections in 1.9 % (n = 72). Overall, P. falciparum was associated with a mean reduction in haemoglobin of 1.16 g/dL compared to those without patent parasitaemia [95 % confidence interval (95 % CI) 0.91, 1.41 g/dL]. The corresponding values for P. vivax and mixed infections were 0.66 g/dL (95 % CI 0.35, 0.96) and 1.25 g/dL (0.71, 1.80), respectively. Overall, 16.7 % (95 % CI 8.52, 24.2 %) of haemoglobin concentrations <7 g/dL in the community were estimated to be attributable to patent parasitaemia. The fractions for infants and 1-5 years old were 34.4 % (95 % CI -3.30, 58.3 %) and 23.2 % (95 % CI 3.34, 39.0 %), respectively. Plasmodium vivax was associated with a greater than threefold higher attributable fraction of anaemia in infants compared with P. falciparum [27.6 % (95 % CI -3.20, 49.2 %) versus 7.94 % (-5.87, 20.0 %)]. Despite comparatively low-level endemicity, malaria is associated with a significant proportion of all cases of community anaemia in southern Papua. Contrary to its benign reputation, P. vivax is an important and preventable risk factor for anaemia during infancy-a probable consequence of relapsing

  17. Susceptibility to Plasmodium yoelii preerythrocytic infection in BALB/c substrains is determined at the point of hepatocyte invasion.

    PubMed

    Kaushansky, Alexis; Austin, Laura S; Mikolajczak, Sebastian A; Lo, Fang Y; Miller, Jessica L; Douglass, Alyse N; Arang, Nadia; Vaughan, Ashley M; Gardner, Malcolm J; Kappe, Stefan H I

    2015-01-01

    After transmission by Anopheles mosquitoes, Plasmodium sporozoites travel to the liver, infect hepatocytes, and rapidly develop as intrahepatocytic liver stages (LS). Rodent models of malaria exhibit large differences in the magnitude of liver infection, both between parasite species and between strains of mice. This has been mainly attributed to differences in innate immune responses and parasite infectivity. Here, we report that BALB/cByJ mice are more susceptible to Plasmodium yoelii preerythrocytic infection than BALB/cJ mice. This difference occurs at the level of early hepatocyte infection, but expression levels of reported host factors that are involved in infection do not correlate with susceptibility. Interestingly, BALB/cByJ hepatocytes are more frequently polyploid; thus, their susceptibility converges on the previously observed preference of sporozoites to infect polyploid hepatocytes. Gene expression analysis demonstrates hepatocyte-specific differences in mRNA abundance for numerous genes between BALB/cByJ and BALB/cJ mice, some of which encode hepatocyte surface molecules. These data suggest that a yet-unknown receptor for sporozoite infection, present at elevated levels on BALB/cByJ hepatocytes and also polyploid hepatocytes, might facilitate Plasmodium liver infection. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  18. Susceptibility to Plasmodium yoelii Preerythrocytic Infection in BALB/c Substrains Is Determined at the Point of Hepatocyte Invasion

    PubMed Central

    Kaushansky, Alexis; Austin, Laura S.; Mikolajczak, Sebastian A.; Lo, Fang Y.; Miller, Jessica L.; Douglass, Alyse N.; Arang, Nadia; Vaughan, Ashley M.; Gardner, Malcolm J.

    2014-01-01

    After transmission by Anopheles mosquitoes, Plasmodium sporozoites travel to the liver, infect hepatocytes, and rapidly develop as intrahepatocytic liver stages (LS). Rodent models of malaria exhibit large differences in the magnitude of liver infection, both between parasite species and between strains of mice. This has been mainly attributed to differences in innate immune responses and parasite infectivity. Here, we report that BALB/cByJ mice are more susceptible to Plasmodium yoelii preerythrocytic infection than BALB/cJ mice. This difference occurs at the level of early hepatocyte infection, but expression levels of reported host factors that are involved in infection do not correlate with susceptibility. Interestingly, BALB/cByJ hepatocytes are more frequently polyploid; thus, their susceptibility converges on the previously observed preference of sporozoites to infect polyploid hepatocytes. Gene expression analysis demonstrates hepatocyte-specific differences in mRNA abundance for numerous genes between BALB/cByJ and BALB/cJ mice, some of which encode hepatocyte surface molecules. These data suggest that a yet-unknown receptor for sporozoite infection, present at elevated levels on BALB/cByJ hepatocytes and also polyploid hepatocytes, might facilitate Plasmodium liver infection. PMID:25312960

  19. Optimization of a Membrane Feeding Assay for Plasmodium vivax Infection in Anopheles albimanus

    PubMed Central

    Vallejo, Andrés F.; Rubiano, Kelly; Amado, Andres; Krystosik, Amy R.; Herrera, Sócrates; Arévalo-Herrera, Myriam

    2016-01-01

    Introduction Individuals exposed to malaria infections for a long time develop immune responses capable of blocking Plasmodium transmission to mosquito vectors, potentially limiting parasite spreading in nature. Development of a malaria TB vaccine requires a better understanding of the mechanisms and main effectors responsible for transmission blocking (TB) responses. The lack of an in vitro culture system for Plasmodium vivax has been an important drawback for development of a standardized method to assess TB responses to this parasite. This study evaluated host, vector, and parasite factors that may influence Anopheles mosquito infection in order to develop an efficient and reliable assay to assess the TB immunity. Methods/Principal Findings A total of 94 P. vivax infected patients were enrolled as parasite donors or subjects of direct mosquito feeding in two malaria endemic regions of Colombia (Tierralta, and Buenaventura). Parasite infectiousness was assessed by membrane feeding assay or direct feeding assay using laboratory reared Anopheles mosquitoes. Infection was measured by qPCR and by microscopically examining mosquito midguts at day 7 for the presence of oocysts. Best infectivity was attained in four day old mosquitoes fed at a density of 100 mosquitos/cage. Membrane feeding assays produced statistically significant better infections than direct feeding assays in parasite donors; cytokine profiles showed increased IFN-γ, TNF and IL-1 levels in non-infectious individuals. Mosquito infections and parasite maturation were more reliably assessed by PCR compared to microscopy. Conclusions We evaluated mosquito, parasite and host factors that may affect the outcome of parasite transmission as measured by artificial membrane feeding assays. Results have led us to conclude that: 1) optimal mosquito infectivity occurs with mosquitoes four days after emergence at a cage density of 100; 2) mosquito infectivity is best quantified by PCR as it may be underestimated

  20. Effects of transmission-blocking immunity on Plasmodium vivax infections in Anopheles albimanus populations.

    PubMed

    Ramsey, J M; Salinas, E; Rodriguez, M H; Beaudoin, R L

    1994-02-01

    Two colonized populations of Anopheles albimanus isolated from the Suchiate region, Chiapas State, Mexico, were compared for their susceptibility to coindigenous Plasmodium vivax. Groups of mosquitoes were fed in vitro with either autologous donor blood or the same blood cells substituted with serum negative for anti-gametocyte antibody. Significant differences in susceptibility between the 2 colonies were encountered if the autologous blood from a patient was fed to mosquitoes: mean infection rates of AnA2-positive groups was double that in AnA1 mosquitoes. Consistent for both colonies, only 23.6% of samples positive from malaria-negative serum-substituted blood were infected with an autologous blood feed. Vector competence in these mosquito populations was partially linked to the human populations's immune response to the parasite.

  1. Hyperparasitaemic human Plasmodium knowlesi infection with atypical morphology in peninsular Malaysia.

    PubMed

    Lee, Wenn-Chyau; Chin, Pek-Woon; Lau, Yee-Ling; Chin, Lit-Chein; Fong, Mun-Yik; Yap, Chee-Jiek; Supramaniam, Raymond Raj; Mahmud, Rohela

    2013-03-06

    Plasmodium knowlesi is a potentially life-threatening zoonotic malaria parasite due to its relatively short erythrocytic cycle. Microscopic identification of P. knowlesi is difficult, with "compacted parasite cytoplasm" being one of the important identifying keys. This report is about a case of hyperparasitaemic human P. knowlesi infection (27% parasitaemia) with atypical amoeboid morphology. A peninsular Malaysian was admitted to the hospital with malaria. He suffered anaemia and acute kidney function impairment. Microscopic examination, assisted by nested PCR and sequencing confirmed as P. knowlesi infection. With anti-malarial treatment and several medical interventions, patient survived and recovered. One-month medical follow-up was performed after recovery and no recrudescence was noted. This case report highlights the extreme hyperparasitaemic setting, the atypical morphology of P. knowlesi in the patient's erythrocytes, as well as the medical interventions involved in this successfully treated case.

  2. Hyperparasitaemic human Plasmodium knowlesi infection with atypical morphology in peninsular Malaysia

    PubMed Central

    2013-01-01

    Plasmodium knowlesi is a potentially life-threatening zoonotic malaria parasite due to its relatively short erythrocytic cycle. Microscopic identification of P. knowlesi is difficult, with “compacted parasite cytoplasm” being one of the important identifying keys. This report is about a case of hyperparasitaemic human P. knowlesi infection (27% parasitaemia) with atypical amoeboid morphology. A peninsular Malaysian was admitted to the hospital with malaria. He suffered anaemia and acute kidney function impairment. Microscopic examination, assisted by nested PCR and sequencing confirmed as P. knowlesi infection. With anti-malarial treatment and several medical interventions, patient survived and recovered. One-month medical follow-up was performed after recovery and no recrudescence was noted. This case report highlights the extreme hyperparasitaemic setting, the atypical morphology of P. knowlesi in the patient’s erythrocytes, as well as the medical interventions involved in this successfully treated case. PMID:23496970

  3. Quantitative non-invasive intracellular imaging of Plasmodium falciparum infected human erythrocytes

    NASA Astrophysics Data System (ADS)

    Edward, Kert; Farahi, Faramarz

    2014-05-01

    Malaria is a virulent pathological condition which results in over a million annual deaths. The parasitic agent Plasmodium falciparum has been extensively studied in connection with this epidemic but much remains unknown about its development inside the red blood cell host. Optical and fluorescence imaging are among the two most common procedures for investigating infected erythrocytes but both require the introduction of exogenous contrast agents. In this letter, we present a procedure for the non-invasive in situ imaging of malaria infected red blood cells. The procedure is based on the utilization of simultaneously acquired quantitative phase and independent topography data to extract intracellular information. Our method allows for the identification of the developmental stages of the parasite and facilitates in situ analysis of the morphological changes associated with the progression of this disease. This information may assist in the development of efficacious treatment therapies for this condition.

  4. Consistent Safety and Infectivity in Sporozoite Challenge Model of Plasmodium vivax in Malaria-Naive Human Volunteers

    PubMed Central

    Herrera, Sócrates; Solarte, Yezid; Jordán-Villegas, Alejandro; Echavarría, Juan Fernando; Rocha, Leonardo; Palacios, Ricardo; Ramírez, Óscar; Vélez, Juan D.; Epstein, Judith E.; Richie, Thomas L.; Arévalo-Herrera, Myriam

    2011-01-01

    A safe and reproducible Plasmodium vivax infectious challenge method is required to evaluate the efficacy of malaria vaccine candidates. Seventeen healthy Duffy (+) and five Duffy (−) subjects were randomly allocated into three (A–C) groups and were exposed to the bites of 2–4 Anopheles albimanus mosquitoes infected with Plasmodium vivax derived from three donors. Duffy (−) subjects were included as controls for each group. Clinical manifestations of malaria and parasitemia were monitored beginning 7 days post-challenge. All Duffy (+) volunteers developed patent malaria infection within 16 days after challenge. Prepatent period determined by thick smear, was longer for Group A (median 14.5 d) than for Groups B and C (median 10 d/each). Infected volunteers recovered rapidly after treatment with no serious adverse events. The bite of as low as two P. vivax-infected mosquitoes provides safe and reliable infections in malaria-naive volunteers, suitable for assessing antimalarial and vaccine efficacy trials. PMID:21292872

  5. Protection of renal function by green tea extract during Plasmodium berghei infection.

    PubMed

    Somsak, Voravuth; Jaihan, Ubonwan; Srichairatanakool, Somdet; Uthaipibull, Chairat

    2013-12-01

    Impairment of renal function from oxidative stress during malaria infection is one of the leading causes of death in endemic areas. Since blood urea nitrogen and creatinine levels in plasma can be used as markers for monitoring renal damage, this study investigated the effect of green tea extract on reduction of blood urea nitrogen and creatinine levels during malaria infection using Plasmodium berghei ANKA infected mice as in vivo model. For in vivo testing, ICR mice were infected with 1 × 10(7) parasitized erythrocytes and green tea extract was subsequently administered orally twice a day for 10 consecutive days. Parasitemia was estimated by standard microscopy, and blood urea nitrogen and creatinine levels in plasma were also measured. It was found that parasitemia kept increasing until animal death, and is strongly correlated with high blood urea nitrogen and creatinine. The highest levels of blood urea nitrogen and creatinine in plasma were found on day 10 after infection. However, blood urea nitrogen and creatinine levels in plasma were reduced and decreased significantly (p<0.01) in green tea extract treated mice, compared with untreated group. It can be concluded that green tea extract can protect and maintain renal function during malaria infection, and this extract can be developed for use as a supplement and combination therapy.

  6. Asymptomatic Multiclonal Plasmodium falciparum Infections Carried Through the Dry Season Predict Protection Against Subsequent Clinical Malaria

    PubMed Central

    Sondén, Klara; Doumbo, Safiatou; Hammar, Ulf; Vafa Homann, Manijeh; Ongoiba, Aissata; Traoré, Boubacar; Bottai, Matteo; Crompton, Peter D.; Färnert, Anna

    2015-01-01

    Background Immunity to the antigenically diverse parasite Plasmodium falciparum is acquired gradually after repeated exposure. Studies in areas of high malaria transmission have shown that asymptomatic individuals infected with multiclonal infections are at reduced risk of febrile malaria during follow-up. Methods We assessed the relationship between the genetic diversity of clones in P. falciparum infections that persist through the dry season and the subsequent risk of febrile malaria in 225 individuals aged 2–25 years in Mali, where the 6-month malaria and dry seasons are sharply demarcated. Polymerase chain reaction–based genotyping of the highly polymorphic merozoite surface protein 2 gene was performed on blood samples collected at 5 cross-sectional surveys. Results In an age-adjusted analysis, individuals with multiclonal P. falciparum infections before the rainy season were at reduced risk of febrile malaria, compared with individuals who were uninfected (hazard ratio [HR], 0.28; 95% confidence interval [CI], .11–.69). In contrast, there was no significant association between risk of malaria and having 1 clone at baseline (HR, 0.71; 95% CI, .36–1.40). Conclusions The results suggest that persistent multiclonal infections carried through the dry season contribute to protection against subsequent febrile malaria, possibly by maintaining protective immune responses that depend on ongoing parasite infection. PMID:25712968

  7. Using infective mosquitoes to challenge monkeys with Plasmodium knowlesi in malaria vaccine studies

    PubMed Central

    2014-01-01

    Background When rhesus monkeys (Macaca mulatta) are used to test malaria vaccines, animals are often challenged by the intravenous injection of sporozoites. However, natural exposure to malaria comes via mosquito bite, and antibodies can neutralize sporozoites as they traverse the skin. Thus, intravenous injection may not fairly assess humoral immunity from anti-sporozoite malaria vaccines. To better assess malaria vaccines in rhesus, a method to challenge large numbers of monkeys by mosquito bite was developed. Methods Several species and strains of mosquitoes were tested for their ability to produce Plasmodium knowlesi sporozoites. Donor monkey parasitaemia effects on oocyst and sporozoite numbers and mosquito mortality were documented. Methylparaben added to mosquito feed was tested to improve mosquito survival. To determine the number of bites needed to infect a monkey, animals were exposed to various numbers of P. knowlesi-infected mosquitoes. Finally, P. knowlesi-infected mosquitoes were used to challenge 17 monkeys in a malaria vaccine trial, and the effect of number of infectious bites on monkey parasitaemia was documented. Results Anopheles dirus, Anopheles crascens, and Anopheles dirus X (a cross between the two species) produced large numbers of P. knowlesi sporozoites. Mosquito survival to day 14, when sporozoites fill the salivary glands, averaged only 32% when donor monkeys had a parasitaemia above 2%. However, when donor monkey parasitaemia was below 2%, mosquitoes survived twice as well and contained ample sporozoites in their salivary glands. Adding methylparaben to sugar solutions did not improve survival of infected mosquitoes. Plasmodium knowlesi was very infectious, with all monkeys developing blood stage infections if one or more infected mosquitoes successfully fed. There was also a dose-response, with monkeys that received higher numbers of infected mosquito bites developing malaria sooner. Conclusions Anopheles dirus, An. crascens and a

  8. [Plasmodium falciparum and Salmonella Typhi co-infection: a case report].

    PubMed

    Sümer, Sua; Ural, Gaye; Ural, Onur

    2014-01-01

    Malaria and salmonella infections are endemic especially in developing countries, however malaria and salmonella co-infection is a rare entity with high mortality. The basic mechanism in developing salmonella co-infection is the impaired mobilization of granulocytes through heme and heme oxygenase which are released from haemoglobin due to the breakdown of erythrocytes during malaria infection. Thus, a malaria infected person becomes more susceptible to develop infection with Salmonella spp. In this report a case with Plasmodium falciparum and Salmonella Typhi co-infection was presented. A 23-year-old male patient was admitted to hospital with the complaints of diarrhea, nausea, vomiting, abdominal pain, fatigue and fever. Laboratory findings yielded decreased number of platelets and increased ALT, AST and CRP levels. Since he had a history of working in Pakistan, malaria infection was considered in differential diagnosis, and the diagnosis was confirmed by the detection of P.falciparum trophozoites in the thick and thin blood smears. As he came from a region with chloroquine-resistant Plasmodium, quinine (3 x 650 mg) and doxycycline (2 x 100 mg/day) were started for the treatment. No erythrocytes, parasite eggs or fungal elements were seen at the stool microscopy of the patient who had diarrhoea during admission. No pathogenic microorganism growth was detected in his stool culture. The patient's blood cultures were also taken in febrile periods starting from the time of his hospitalization. A bacterial growth was observed in his blood cultures, and the isolate was identified as S. Typhi. Thus, the patient was diagnosed with P.falciparum and Salmonella Typhi coinfection. Ceftriaxone (1 x 2 g/day, 14 days) was added to the therapy according to the results of antibiotic susceptibility test. With the combined therapy (quinine, doxycycline, ceftriaxone) the fever was taken under control, his general condition improved and laboratory findings turned to normal values

  9. Phospholipid metabolism of serine in Plasmodium-infected erythrocytes involves phosphatidylserine and direct serine decarboxylation.

    PubMed Central

    Elabbadi, N; Ancelin, M L; Vial, H J

    1997-01-01

    Erythrocytes infected with Plasmodium falciparum or Plasmodium knowlesi efficiently incorporated radioactive serine into phosphatidylserine (PtdSer), phosphatidylethanolamine (PtdEtn) and phosphatidylcholine (PtdCho). Serine was also metabolized into ethanolamine (Etn) and phosphorylethanolamine (P-Etn) via direct serine decarboxylation; this is a major phenomenon since together these metabolites represent 60% of total radioactive water-soluble metabolites. They were identified by reverse-phase HPLC and two TLC-type analyses and confirmed by alkaline phosphatase treatment, which depleted the radioactive P-Etn peak completely with a concomitant increase in that of Etn. In the presence of 5 microM labelled serine, radioactivity appeared in Etn and P-Etn after a 25 min lag period, and isotopic equilibrium was reached at 40 and 95 min respectively. There was a similar lag period for PtdEtn formation, which accumulated steadily for at least 180 min. Incorporation of serine into phospholipids and water-soluble metabolites increased in the presence of up to 500 microM external serine. An apparent plateau was then reached for all metabolites except intracellular serine and Etn. Exogenous Etn (at 20 microM) induced a concomitant dramatic decrease in serine incorporation into P-Etn and all phospholipids, but not into Etn. Increasing exogenous serine to 100 microM decreased the incorporation of radioactive Etn into PtdEtn by only 30%, and the PtdCho level was not affected. 2-Hydroxyethylhydrazine significantly decreased serine incorporation into P-Etn and PtdEtn, whereas Etn was accumulated. No concomitant inhibition of PtdSer or PtdCho labelling from serine occurred, even when PtdEtn formation was decreased by 95%. This indicates that the PtdEtn pool derived from direct serine decarboxylation differed from that derived from PtdSer decarboxylation, and the latter appeared to be preferentially used for PtdCho biosynthesis. Hydroxylamine also inhibited phosphorylation of serine

  10. Natural human Plasmodium infections in major Anopheles mosquitoes in western Thailand.

    PubMed

    Sriwichai, Patchara; Samung, Yudthana; Sumruayphol, Suchada; Kiattibutr, Kirakorn; Kumpitak, Chalermpon; Payakkapol, Anon; Kaewkungwal, Jaranit; Yan, Guiyun; Cui, Liwang; Sattabongkot, Jetsumon

    2016-01-13

    The Thai-Myanmar border is a remaining hotspot for malaria transmission. Malaria transmission in this region continues year-round, with a major peak season in July-August, and a minor peak in October-November. Malaria elimination requires better knowledge of the mosquito community structure, dynamics and vectorial status to support effective vector control. Adult Anopheles mosquitoes were collected using CDC light traps and cow bait in 7 villages along the Thai-Myanmar border in January 2011 - March 2013. Mosquitoes were determined to species by morphological characters. Plasmodium-positivity was determined by circumsporozoite protein ELISA. The 2986 Anopheles mosquitoes collected were assigned to 26 species, with Anopheles minimus sensu lato (s.l.) (40.32%), An. maculatus s.l. (21.43%), An. annularis s.l. (14.43%), An. kochi (5.39%), An. tessellatus (5.26%), and An. barbirostris s.l. (3.52%) being the top six most abundant species. Plasmodium-infected mosquitoes were found in 22 positive samples from 2906 pooled samples of abdomens and heads/thoraxes. Four mosquito species were found infected with Plasmodium: An. minimus s.l., An. maculatus s.l., An. annularis s.l. and An. barbirostris s.l. The infectivity rates of these mosquitoes were 0.76, 0.37, 0.72, and 1.74%, respectively. Consistent with a change in malaria epidemiology to the predominance of P. vivax in this area, 20 of the 22 infected mosquito samples were P. vivax-positive. The four potential vector species all displayed apparent seasonality in relative abundance. While An. minimus s.l. was collected through the entire year, its abundance peaked in the season immediately after the wet season. In comparison, An. maculatus s.l. numbers showed a major peak during the wet season. The two potential vector species, An. annularis s.l. and An. barbirostris s.l., both showed peak abundance during the transition from wet to dry season. Moreover, An. minimus s.l. was more abundant in indoor collections, whereas An

  11. Influence of amitriptyline on eryptosis, parasitemia and survival of Plasmodium berghei-infected mice.

    PubMed

    Brand, Verena; Koka, Saisudha; Lang, Camelia; Jendrossek, Verena; Huber, Stephan M; Gulbins, Erich; Lang, Florian

    2008-01-01

    Plasmodia express a sphingomyelinase, which is apparently required for their development. On the other hand, the sphingomyelinase product ceramide has previously been shown to delay parasite development. Moreover, ceramide triggers suicidal erythrocyte death or eryptosis, characterized by exposure of phosphatidylserine at the erythrocyte surface and cell shrinkage. Accelerated eryptosis of infected erythrocytes is considered to clear infected erythrocytes from circulating blood and, thus, to favourably influence the clinical course of malaria. The present experiments explored whether the sphingomyelinase inhibitor amitriptyline or genetic knockout of host acid sphingomyelinase influence in vitro parasite growth, eryptosis of Plasmodium falciparum-infected human erythrocytes, in vivo parasitemia and survival of P. berghei-infected mice. Phosphatidylserine exposure was determined by annexin V-binding and cell volume by forward scatter in FACS analysis. In vitro infection of human erythrocytes increased annexin- binding, an effect blunted in the presence of amitriptyline (>or=50 microM). Amitriptyline did not significantly alter intraerythrocytic parasite development but significantly (>or= 1 microM) delayed the increase in parasitemia in vitro. Most importantly, amitriptyline treatment (1 mM in drinking water) resulted in a significant delay of parasitemia and death of infected mice. However, upon infection, ceramide formation was stimulated in both, acid sphingomyelinase knockout mice (Smpd1(-/-)) and their wild type littermates (Smpd1(+/+)). Parasitemia following P. berghei infection was significantly lower in Smpd1(-/-) than in Smpd1(+/+) mice but did not significantly extend the life span of infected animals. In conclusion, mammalian and parasite sphingomyelinase contribute to ceramide formation during malaria, whereby the parasite sphingomyelinase ultimately determines the course of the infection. Amitriptyline presumably blocks both sphingomyelinases and, thus

  12. Infants' Peripheral Blood Lymphocyte Composition Reflects Both Maternal and Post-Natal Infection with Plasmodium falciparum

    PubMed Central

    Ibitokou, Samad; Vianou, Bertin; Houngbegnon, Parfait; Ezinmegnon, Sem; Borgella, Sophie; Akplogan, Carine; Cottrell, Gilles; Varani, Stefania; Massougbodji, Achille; Moutairou, Kabirou; Troye-Blomberg, Marita; Deloron, Philippe; Luty, Adrian J. F.; Fievet, Nadine

    2015-01-01

    Maternal parasitoses modulate fetal immune development, manifesting as altered cellular immunological activity in cord blood that may be linked to enhanced susceptibility to infections in early life. Plasmodium falciparum typifies such infections, with distinct placental infection-related changes in cord blood exemplified by expanded populations of parasite antigen-specific regulatory T cells. Here we addressed whether such early-onset cellular immunological alterations persist through infancy. Specifically, in order to assess the potential impacts of P. falciparum infections either during pregnancy or during infancy, we quantified lymphocyte subsets in cord blood and in infants' peripheral blood during the first year of life. The principal age-related changes observed, independent of infection status, concerned decreases in the frequencies of CD4+, NKdim and NKT cells, whilst CD8+, Treg and Teff cells' frequencies increased from birth to 12 months of age. P. falciparum infections present at delivery, but not those earlier in gestation, were associated with increased frequencies of Treg and CD8+ T cells but fewer CD4+ and NKT cells during infancy, thus accentuating the observed age-related patterns. Overall, P. falciparum infections arising during infancy were associated with a reversal of the trends associated with maternal infection i.e. with more CD4+ cells, with fewer Treg and CD8+ cells. We conclude that maternal P. falciparum infection at delivery has significant and, in some cases, year-long effects on the composition of infants' peripheral blood lymphocyte populations. Those effects are superimposed on separate and independent age- as well as infant infection-related alterations that, respectively, either match or run counter to them. PMID:26580401

  13. Role of the Plasmodium Export Element in Trafficking Parasite Proteins to the Infected Erythrocyte

    PubMed Central

    Boddey, Justin A; Moritz, Robert L; Simpson, Richard J; Cowman, Alan F

    2009-01-01

    The intracellular survival of Plasmodium falciparum within human erythrocytes is dependent on export of parasite proteins that remodel the host cell. Most exported proteins require a conserved motif (RxLxE/Q/D), termed the Plasmodium export element (PEXEL) or vacuolar targeting sequence (VTS), for targeting beyond the parasitophorous vacuole membrane and into the host cell; however, the precise role of this motif in export is poorly defined. We used transgenic P. falciparum expressing chimeric proteins to investigate the function of the PEXEL motif for export. The PEXEL constitutes a bifunctional export motif comprising a protease recognition sequence that is cleaved, in the endoplasmic reticulum, from proteins destined for export, in a PEXEL arginine- and leucine-dependent manner. Following processing, the remaining conserved PEXEL residue is required to direct the mature protein to the host cell. Furthermore, we demonstrate that N acetylation of proteins following N-terminal processing is a PEXEL-independent process that is insufficient for correct export to the host cell. This work defines the role of each residue in the PEXEL for export into the P. falciparum-infected erythrocyte. PMID:19055692

  14. Pathogenicity and chemotherapy of Plasmodium durae in experimentally infected domestic turkeys.

    PubMed

    Huchzermeyer, F W

    1993-06-01

    Only 3 out of 8 South African isolates of Plasmodium durae used in 524 turkeys in 161 passages caused approximately 50% mortality, a further 3 produced approximately 10% mortality while 2 were found to be apathogenic. Exoerythrocytic schizonts were the main pathogenic stage. In most survivors the effect on mass gains was minimal. Twelve drugs currently available for use in poultry, as well as chloroquin phosphate, were tested for their activity against experimental infections with Plasmodium durae in domestic turkeys. While chloroquin phosphate showed a certain degree of effectivity, Amprolium, Amprolium + Ethopabate, Maduramycin, Toltrazuril, Metronidazole, Furazolidone, Enrofloxacin and Sulfamethoxypyridazine + Trimethoprim were ineffective. Halofuginone and Penta-Sulfa at a high dose had some protective effect. At high doses Sulfachloropyrazine protected from mortality without affecting the parasitaemia, while Sulfamonomethoxine suppressed parasitaemia without entirely protecting from mortality. From these data it is concluded that Halofuginone has a potential as possible chemoprophylactic. While a combination of Sulfamonomethoxine and Sulfachloropyrazine could be used in the treatment of outbreaks in the field.

  15. Therapeutic efficacy of artemether-lumefantrine for Plasmodium vivax infections in a prospective study in Guyana

    PubMed Central

    2012-01-01

    Background In Guyana, chloroquine + primaquine is used for the treatment of vivax malaria. A worldwide increase of chloroquine resistance in Plasmodium vivax led to questioning of the current malaria treatment guidelines. A therapeutic efficacy study was conducted using artemether-lumefantrine + primaquine against P. vivax to evaluate a treatment alternative for chloroquine. Methods From 2009 to 2010, a non-controlled study in two hospitals in Guyana was conducted. A total 61 patients with P. vivax infection were treated with artemether-lumefantrine as a six-dose regimen twice a day for three days with additional 0.25 mg/kg/d primaquine at day 0 for 14 days. Clinical and parasitological parameters were followed on days 0,1,2,3,7,14 and 28 in agreement with WHO guidelines. Plasmodium vivax DNA from eight patients was analysed for pvmdr1, molecular marker of resistance. Results Artemether-lumefantrine cleared 100% of parasites on day 1, but two patients (3%) had recurrence of parasites on day 28, suggesting relapse. No pvmdr1 Y976F polymorphism was detected. The treatment regimen was well tolerated. Conclusions In Guyana, artemether-lumefantrine represents an adequate treatment option against P. vivax when combined with primaquine. Availability of this alternative will be of great importance in case of emerging chloroquine resistance against P. vivax. PMID:23083017

  16. Expression of PD-1/LAG-3 and cytokine production by CD4(+) T cells during infection with Plasmodium parasites.

    PubMed

    Doe, Henrietta T; Kimura, Daisuke; Miyakoda, Mana; Kimura, Kazumi; Akbari, Masoud; Yui, Katsuyuki

    2016-02-01

    CD4(+) T cells play critical roles in protection against the blood stage of malarial infection; however, their uncontrolled activation can be harmful to the host. In this study, in which rodent models of Plasmodium parasites were used, the expression of inhibitory receptors on activated CD4(+) T cells and their cytokine production was compared with their expression in a bacterial and another protozoan infection. CD4(+) T cells from mice infected with P. yoelii 17XL, P yoelii 17XNL, P. chabaudi, P. vinckei and P. berghei expressed the inhibitory receptors, PD-1 and LAG-3, as early as 6 days after infection, whereas those from either Listeria monocytogenes- or Leishmania major-infected mice did not. In response to T-cell receptor stimulation, CD4(+) T cells from mice infected with all the pathogens under study produced high concentrations of IFN-γ. IL-2 production was reduced in mice infected with Plasmodium species, but not in those infected with Listeria or Leishmania. In vitro blockade of the interaction between PD-1 and its ligands resulted in increased IFN-γ production in response to Plasmodium antigens, implying that PD-1 expressed on activated CD4(+) T cells actively inhibits T cell immune responses. Studies using Myd88(-/-), Trif(-/-) and Irf3(-/-) mice showed that induction of these CD4(+) T cells and their ability to produce cytokines is largely independent of TLR signaling. These studies suggest that expression of the inhibitory receptors PD-1 and LAG-3 on CD4(+) T cells and their reduced IL-2 production are common characteristic features of Plasmodium infection.

  17. Persistence of Plasmodium falciparum parasites in infected pregnant Mozambican women after delivery.

    PubMed

    Serra-Casas, Elisa; Menéndez, Clara; Dobaño, Carlota; Bardají, Azucena; Quintó, Llorenç; Quintó, Llorençc; Ordi, Jaume; Sigauque, Betuel; Cisteró, Pau; Mandomando, Inacio; Alonso, Pedro L; Mayor, Alfredo

    2011-01-01

    Pregnant women are susceptible to Plasmodium falciparum parasites that sequester in the placenta. The massive accumulation of infected erythrocytes in the placenta has been suggested to trigger the deleterious effects of malaria in pregnant women and their offspring. The risk of malaria is also high during the postpartum period, although mechanisms underlying this susceptibility are not known. Here, we aimed to identify host factors contributing to the risk of postpartum infections and to determine the origin of postpartum parasites by comparing their genotypes with those present at the time of delivery. To address this, blood samples were collected at delivery (n = 402) and postpartum (n = 354) from Mozambican women enrolled in a trial of intermittent preventive treatment in pregnancy (IPTp). P. falciparum was detected by real-time quantitative PCR (qPCR), and the parasite merozoite surface protein 1 (msp-1) and msp-2 genes were genotyped. Fifty-seven out of 354 (16%) women were infected postpartum as assessed by qPCR, whereas prevalence by optical microscopy was only 4%. Risk of postpartum infection was lower in older women (odds ratio [OR] = 0.34, 95% confidence interval [CI] = 0.15 to 0.81) and higher in women with a placental infection at delivery (OR = 4.20, 95% CI = 2.19 to 8.08). Among 24 women with matched infections, 12 (50%) were infected postpartum with at least one parasite strain that was also present in their placentas. These results suggest that parasites infecting pregnant women persist after delivery and increase the risk of malaria during the postpartum period. Interventions that reduce malaria during pregnancy may translate into a lower risk of postpartum infection.

  18. Effects of low protein diet and pregnancy on course of Plasmodium berghei infection in mice.

    PubMed

    Rabiu, O R; Arinola, O G; Odaibo, A B; Ademowo, O G

    2012-12-01

    Pregnancy and malnutrition influence the severity or trend of malaria especially in sub-Saharan Africa where parasitic infections are highly predominant. This study was used to evaluate the combined effects of low protein diet and pregnancy on the course of Plasmodium berghei infection in mice. Thirty female BALB/c mice were divided into six groups viz: Non-infected mice fed on normal diet (NIND), Infected mice fed on normal diet (IND), Noninfected mice fed on low protein diet (NILP), Infected mice fed on low protein diet (ILP), Non-infected gravid mice fed on low protein diet (NIGLP) and Gravid infected mice fed on low protein diet (GILP). Malaria parasite count, packed cell volume, body weight and plasma nitric oxide (NO) production were determined. Data were compared statistically across the groups using Student t-test and ANOVA. Parasite detection in peripheral blood was delayed in ILP (day 7) and GILP (day 11) relative to IND (day 3). The peak parasitaemia and mean survival time were significantly lower (p < 0.05) in GILP relative to other infected groups. GILP could not carry the pregnancy to term. Nitric oxide production was observed to increase more rapidly in IND relative to ILP after parasite detection with a peak production by day 15. Mortality commenced in both groups afterwards. Low protein diet delayed the peak production of NO supporting its protective influence on malaria infection. However, the combined effects of low protein diet and pregnancy resulted in early mortality and inability of mice to carry pregnancy to term.

  19. Lipid traffic between high density lipoproteins and Plasmodium falciparum-infected red blood cells

    PubMed Central

    1991-01-01

    Several intraerythrocytic growth cycles of Plasmodium falciparum could be achieved in vitro using a serum free medium supplemented only with a human high density lipoprotein (HDL) fraction (d = 1.063-1.210). The parasitemia obtained was similar to that in standard culture medium containing human serum. The parasite development was incomplete with the low density lipoprotein (LDL) fraction and did not occur with the VLDL fraction. The lipid traffic from HDL to the infected erythrocytes was demonstrated by pulse labeling experiments using HDL loaded with either fluorescent NBD-phosphatidylcholine (NBD-PC) or radioactive [3H]palmitoyl-PC. At 37 degrees C, the lipid probes rapidly accumulated in the infected cells. After incubation in HDL medium containing labeled PC, a subsequent incubation in medium with either an excess of native HDL or 20% human serum induced the disappearance of the label from the erythrocyte plasma membrane but not from the intraerythrocytic parasite. Internalization of lipids did not occur at 4 degrees C. The mechanism involved a unidirectional flux of lipids but no endocytosis. The absence of labeling of P. falciparum, with HDL previously [125I]iodinated on their apolipoproteins or with antibodies against the apolipoproteins AI and AII by immunofluorescence and immunoblotting, confirmed that no endocytosis of the HDL was involved. A possible pathway of lipid transport could be a membrane flux since fluorescence videomicroscopy showed numerous organelles labeled with NBD-PC moving between the erythrocyte and the parasitophorous membranes. TLC analysis showed that a partial conversion of the PC to phosphatidylethanolamine was observed in P. falciparum-infected red cells after pulse with [3H]palmitoyl-PC-HDL. The intensity of the lipid traffic was stage dependent with a maximum at the trophozoite and young schizont stages (38th h of the erythrocyte life cycle). We conclude that the HDL fraction appears to be a major lipid source for Plasmodium

  20. High Rates of Asymptomatic, Sub-microscopic Plasmodium vivax Infection and Disappearing Plasmodium falciparum Malaria in an Area of Low Transmission in Solomon Islands.

    PubMed

    Waltmann, Andreea; Darcy, Andrew W; Harris, Ivor; Koepfli, Cristian; Lodo, John; Vahi, Ventis; Piziki, David; Shanks, G Dennis; Barry, Alyssa E; Whittaker, Maxine; Kazura, James W; Mueller, Ivo

    2015-05-01

    Solomon Islands is intensifying national efforts to achieve malaria elimination. A long history of indoor spraying with residual insecticides, combined recently with distribution of long lasting insecticidal nets and artemether-lumefantrine therapy, has been implemented in Solomon Islands. The impact of these interventions on local endemicity of Plasmodium spp. is unknown. In 2012, a cross-sectional survey of 3501 residents of all ages was conducted in Ngella, Central Islands Province, Solomon Islands. Prevalence of Plasmodium falciparum, P. vivax, P. ovale and P. malariae was assessed by quantitative PCR (qPCR) and light microscopy (LM). Presence of gametocytes was determined by reverse transcription quantitative PCR (RT-qPCR). By qPCR, 468 Plasmodium spp. infections were detected (prevalence = 13.4%; 463 P. vivax, five mixed P. falciparum/P. vivax, no P. ovale or P. malariae) versus 130 by LM (prevalence = 3.7%; 126 P. vivax, three P. falciparum and one P. falciparum/P. vivax). The prevalence of P. vivax infection varied significantly among villages (range 3.0-38.5%, p<0.001) and across age groups (5.3-25.9%, p<0.001). Of 468 P. vivax infections, 72.9% were sub-microscopic, 84.5% afebrile and 60.0% were both sub-microscopic and afebrile. Local residency, low education level of the household head and living in a household with at least one other P. vivax infected individual increased the risk of P. vivax infection. Overall, 23.5% of P. vivax infections had concurrent gametocytaemia. Of all P. vivax positive samples, 29.2% were polyclonal by MS16 and msp1F3 genotyping. All five P. falciparum infections were detected in residents of the same village, carried the same msp2 allele and four were positive for P. falciparum gametocytes. P. vivax infection remains endemic in Ngella, with the majority of cases afebrile and below the detection limit of LM. P. falciparum has nearly disappeared, but the risk of re-introductions and outbreaks due to travel to nearby islands

  1. High Rates of Asymptomatic, Sub-microscopic Plasmodium vivax Infection and Disappearing Plasmodium falciparum Malaria in an Area of Low Transmission in Solomon Islands

    PubMed Central

    Waltmann, Andreea; Darcy, Andrew W.; Harris, Ivor; Koepfli, Cristian; Lodo, John; Vahi, Ventis; Piziki, David; Shanks, G. Dennis; Barry, Alyssa E.; Whittaker, Maxine; Kazura, James W.; Mueller, Ivo

    2015-01-01

    Introduction Solomon Islands is intensifying national efforts to achieve malaria elimination. A long history of indoor spraying with residual insecticides, combined recently with distribution of long lasting insecticidal nets and artemether-lumefantrine therapy, has been implemented in Solomon Islands. The impact of these interventions on local endemicity of Plasmodium spp. is unknown. Methods In 2012, a cross-sectional survey of 3501 residents of all ages was conducted in Ngella, Central Islands Province, Solomon Islands. Prevalence of Plasmodium falciparum, P. vivax, P. ovale and P. malariae was assessed by quantitative PCR (qPCR) and light microscopy (LM). Presence of gametocytes was determined by reverse transcription quantitative PCR (RT-qPCR). Results By qPCR, 468 Plasmodium spp. infections were detected (prevalence = 13.4%; 463 P. vivax, five mixed P. falciparum/P. vivax, no P. ovale or P. malariae) versus 130 by LM (prevalence = 3.7%; 126 P. vivax, three P. falciparum and one P. falciparum/P. vivax). The prevalence of P. vivax infection varied significantly among villages (range 3.0–38.5%, p<0.001) and across age groups (5.3–25.9%, p<0.001). Of 468 P. vivax infections, 72.9% were sub-microscopic, 84.5% afebrile and 60.0% were both sub-microscopic and afebrile. Local residency, low education level of the household head and living in a household with at least one other P. vivax infected individual increased the risk of P. vivax infection. Overall, 23.5% of P. vivax infections had concurrent gametocytaemia. Of all P. vivax positive samples, 29.2% were polyclonal by MS16 and msp1F3 genotyping. All five P. falciparum infections were detected in residents of the same village, carried the same msp2 allele and four were positive for P. falciparum gametocytes. Conclusion P. vivax infection remains endemic in Ngella, with the majority of cases afebrile and below the detection limit of LM. P. falciparum has nearly disappeared, but the risk of re-introductions and

  2. Peripheral Blood Stem Cell Transplant Related Plasmodium falciparum Infection in a Patient with Sickle Cell Disease

    PubMed Central

    Mejia, Rojelio; Booth, Garrett S.; Fedorko, Daniel P.; Hsieh, Matthew M.; Khuu, Hanh M.; Klein, Harvey G.; Mu, Jianbing; Fahle, Gary; Nutman, Thomas B.; Su, Xin-Zhuan; Williams, Esther C.; Flegel, Willy A.; Klion, Amy

    2012-01-01

    Background Although transmission of Plasmodium falciparum (Pf) infection during red blood cell transfusion from an infected donor has been well documented, malaria parasites are not known to infect hematopoietic stem cells. We report a case of Pf infection in a patient 11 days after peripheral blood stem cell transplant for sickle cell disease. Study Design and Methods Malaria parasites were detected in thick blood smears by Giemsa staining. Pf HRP2 antigen was measured by ELISA on whole blood and plasma. Pf DNA was detected in whole blood and stem cell retention samples by real-time PCR using Pf species–specific primers and probes. Genotyping of 8 Pf microsatellites was performed on genomic DNA extracted from whole blood. Results Pf was not detected by molecular, serologic or parasitologic means in samples from the recipient until day 11 post-transplant, coincident with the onset of symptoms. In contrast, Pf antigen was retrospectively detected in stored plasma collected 3 months prior to transplant from the asymptomatic donor. Pf DNA was detected in whole blood from both the donor and recipient post-transplant, and genotyping confirmed shared markers between donor and recipient Pf strains. Look back analysis of red blood cell donors was negative for Pf infection. Conclusions These findings are consistent with transmission by the stem cell product and have profound implications with respect to the screening of potential stem cell donors and recipients from malaria-endemic regions. PMID:22536941

  3. Antecedent Nippostrongylus infection alters the lung immune response to Plasmodium berghei.

    PubMed

    Craig, J M; Scott, A L

    2017-08-01

    In endemic regions, it is not uncommon for patients to be co-infected with soil-transmitted helminths and malaria. Although both malaria and many helminth species use the lungs as a site of development, little attention has been paid to the impact that pulmonary immunity induced by one parasite has on the lung response to the other. To model the consequences of a prior hookworm exposure on the development of immunity to malaria in the lungs, mice were infected with Nippostrongylus brasiliensis and 2 weeks later challenged with Plasmodium berghei. We found that a pre-existing hookworm-induced type 2 immune environment had a measurable but modest impact on the nature of the malaria-driven type 1 cytokine response in the lungs that was associated with a transient effect on parasite development and no significant changes in morbidity and mortality after malaria infection. However, prior hookworm infection did have a lasting effect on lung macrophages, where the malaria-induced M1-like response was blunted by previous M2 polarization. These results demonstrate that, although helminth parasites confer robust changes to the immunological status of the pulmonary microenvironment, lung immunity is plastic and capable of rapidly adapting to consecutive heterologous infections. © 2017 John Wiley & Sons Ltd.

  4. Production of luminol-reactive oxygen radicals during Plasmodium vinckei infection.

    PubMed Central

    Stocker, R; Hunt, N H; Clark, I A; Weidemann, M J

    1984-01-01

    We tested the ability of whole blood and enriched fractions of peripheral blood polymorphonuclear leukocytes obtained from mice during the course of infection with Plasmodium vinckei to produce luminol-mediated chemiluminescence in response to phagocytic and nonphagocytic stimuli. The chemiluminescence response of whole blood to all stimuli increased dramatically and nonlinearly as the infection progressed, and there was a concomitant increase (80%) and decrease (70%) in the total numbers of leukocytes and erythrocytes, respectively. The proportion of polymorphonuclear leukocytes in the total leukocyte population increased threefold. On a per cell basis and at a constant hematocrit, the chemiluminescence response of peripheral leukocytes from infected animals to phorbol myristate acetate or opsonized zymosan was only slightly greater than that of cells from uninfected animals. Polymorphonuclear leukocytes isolated from the blood of infected animals also showed no large increase per cell in chemiluminescence responsiveness. Thus, although leukocyte numbers increase during a murine malarial infection, there appears to be no major change in the capacity of individual peripheral blood leukocytes to produce activated species of oxygen. However, the physiological reduction in the total concentration of hemoglobin at high parasitemia, due to hemolysis and hemoglobin digestion by the parasites, increases the possibility of oxygen radical-mediated damage to tissues and intraerythrocytic parasites as a result of decreased antioxidant protection. PMID:6469357

  5. Effects of Maternal Plasmodium falciparum Malaria and HIV infection on Birth Weight in Southeastern Nigeria

    PubMed Central

    Uneke, Chigozie J.; Duhlinska, Dochka D.; Ujam, Treasure N.

    2009-01-01

    The effects of malaria and HIV infection on birth weight were assessed among 300 women in childbirth in Southeastern Nigeria using standard techniques. Prevalence of maternal Plasmodium falciparum malaria infection was 16.0%. Individuals of younger age, primigravidae, anemic (with Hgb <11.0g/dl) and those who had never attended antenatal clinic (ANC) were more likely to have malaria infection. Prevalence of HIV infection was 3.6% and malaria prevalence was significantly higher among HIV-positive than HIV-negative women (37.5%, 95% CI, 4.0-71.0% versus 14.3%, 95% CI., 9.6-19.0%), (χ2 =13.3, P<0.05). Malaria-infected women had a significantly higher proportion of lBW babies than the uninfected (F-ratio=15.05, P<0.05). A higher proportion of low birth weight (lBW) was recorded among anemic women, primigravidae and those who never attended ANC. lBW babies were significantly higher among HIV-positive than HIV-negative women (25.0% vs 16.6%), (F-ratio=130.8, P<0.05). Malaria and HIV interventions via ANC are crucial for reduction of their adverse effects on pregnancy outcome. PMID:21152333

  6. Further evaluation of the NWF filter for the purification of Plasmodium vivax-infected erythrocytes.

    PubMed

    Li, Jiangyan; Tao, Zhiyong; Li, Qian; Brashear, Awtum; Wang, Ying; Xia, Hui; Fang, Qiang; Cui, Liwang

    2017-05-17

    Isolation of Plasmodium-infected red blood cells (iRBCs) from clinical blood samples is often required for experiments, such as ex vivo drug assays, in vitro invasion assays and genome sequencing. Current methods for removing white blood cells (WBCs) from malaria-infected blood are time-consuming or costly. A prototype non-woven fabric (NWF) filter was developed for the purification of iRBCs, which showed great efficiency for removing WBCs in a pilot study. Previous work was performed with prototype filters optimized for processing 5-10 mL of blood. With the commercialization of the filters, this study aims to evaluate the efficiency and suitability of the commercial NWF filter for the purification of Plasmodium vivax-infected RBCs in smaller volumes of blood and to compare its performance with that of Plasmodipur(®) filters. Forty-three clinical P. vivax blood samples taken from symptomatic patients attending malaria clinics at the China-Myanmar border were processed using the NWF filters in a nearby field laboratory. The numbers of WBCs and iRBCs and morphology of P. vivax parasites in the blood samples before and after NWF filtration were compared. The viability of P. vivax parasites after filtration from 27 blood samples was examined by in vitro short-term culture. In addition, the effectiveness of the NWF filter for removing WBCs was compared with that of the Plasmodipur(®) filter in six P. vivax blood samples. Filtration of 1-2 mL of P. vivax-infected blood with the NWF filter removed 99.68% WBCs. The densities of total iRBCs, ring and trophozoite stages before and after filtration were not significantly different (P > 0.05). However, the recovery rates of schizont- and gametocyte-infected RBCs, which were minor parasite stages in the clinical samples, were relatively low. After filtration, the P. vivax parasites did not show apparent morphological changes. Culture of 27 P. vivax-infected blood samples after filtration showed that parasites successfully

  7. Transgenic mosquitoes expressing a phospholipase A(2) gene have a fitness advantage when fed Plasmodium falciparum-infected blood.

    PubMed

    Smith, Ryan C; Kizito, Christopher; Rasgon, Jason L; Jacobs-Lorena, Marcelo

    2013-01-01

    Genetically modified mosquitoes have been proposed as an alternative strategy to reduce the heavy burden of malaria. In recent years, several proof-of-principle experiments have been performed that validate the idea that mosquitoes can be genetically modified to become refractory to malaria parasite development. We have created two transgenic lines of Anophelesstephensi, a natural vector of Plasmodium falciparum, which constitutively secrete a catalytically inactive phospholipase A2 (mPLA2) into the midgut lumen to interfere with Plasmodium ookinete invasion. Our experiments show that both transgenic lines expressing mPLA2 significantly impair the development of rodent malaria parasites, but only one line impairs the development of human malaria parasites. In addition, when fed on malaria-infected blood, mosquitoes from both transgenic lines are more fecund than non-transgenic mosquitoes. Consistent with these observations, cage experiments with mixed populations of transgenic and non-transgenic mosquitoes show that the percentage of transgenic mosquitoes increases when maintained on Plasmodium-infected blood. Our results suggest that the expression of an anti-Plasmodium effector gene gives transgenic mosquitoes a fitness advantage when fed malaria-infected blood. These findings have important implications for future applications of transgenic mosquito technology in malaria control.

  8. Transgenic Mosquitoes Expressing a Phospholipase A2 Gene Have a Fitness Advantage When Fed Plasmodium falciparum-Infected Blood

    PubMed Central

    Smith, Ryan C.; Kizito, Christopher; Rasgon, Jason L.; Jacobs-Lorena, Marcelo

    2013-01-01

    Background Genetically modified mosquitoes have been proposed as an alternative strategy to reduce the heavy burden of malaria. In recent years, several proof-of-principle experiments have been performed that validate the idea that mosquitoes can be genetically modified to become refractory to malaria parasite development. Results We have created two transgenic lines of Anophelesstephensi, a natural vector of Plasmodium falciparum, which constitutively secrete a catalytically inactive phospholipase A2 (mPLA2) into the midgut lumen to interfere with Plasmodium ookinete invasion. Our experiments show that both transgenic lines expressing mPLA2 significantly impair the development of rodent malaria parasites, but only one line impairs the development of human malaria parasites. In addition, when fed on malaria-infected blood, mosquitoes from both transgenic lines are more fecund than non-transgenic mosquitoes. Consistent with these observations, cage experiments with mixed populations of transgenic and non-transgenic mosquitoes show that the percentage of transgenic mosquitoes increases when maintained on Plasmodium-infected blood. Conclusions Our results suggest that the expression of an anti-Plasmodium effector gene gives transgenic mosquitoes a fitness advantage when fed malaria-infected blood. These findings have important implications for future applications of transgenic mosquito technology in malaria control. PMID:24098427

  9. Multivariable analysis of host amino acids in plasma and liver during infection of malaria parasite Plasmodium yoelii

    PubMed Central

    2013-01-01

    Background Malaria is the most significant human parasitic disease, and yet understanding of the energy metabolism of the principle pathogen, Plasmodium falciparum, remains to be fully elucidated. Amino acids were shown to be essential nutritional requirements since early times and much of the current knowledge of Plasmodium energy metabolism is based on early biochemical work, performed using basic analytical techniques, carried out almost exclusively on human plasma with considerable inter-individual variability. Methods In order to further characterize the fate of amino acid metabolism in malaria parasite, multivariate analysis using statistical modelling of amino acid concentrations (aminogram) of plasma and liver were determined in host infected with rodent malaria parasite, Plasmodium yoelii. Results and conclusion Comprehensive and statistical aminogram analysis revealed that P. yoelii infection caused drastic change of plasma and liver aminogram, and altered intra- and inter-correlation of amino acid concentration in plasma and liver. These findings of the interactions between amino acids and Plasmodium infection may provide insight to reveal the interaction between nutrients and parasites. PMID:23324562

  10. Implications of Plasmodium parasite infected mosquitoes on an insular avifauna: the case of Socorro Island, México.

    PubMed

    Carlson, Jenny S; Martínez-Gómez, Juan E; Cornel, Anthony; Loiseau, Claire; Sehgal, Ravinder N M

    2011-06-01

    Avian malaria (Plasmodium spp.) has been implicated in the decline of avian populations in the Hawaiian Islands and it is generally agreed that geographically isolated and immunologically naïve bird populations are particularly vulnerable to the pathogenic effects of invasive malaria parasites. In order to assess the potential disease risk of malaria to the avifauna of Socorro Island, México, we surveyed for Plasmodium isolates from 1,300 resident field-caught mosquitoes. Most of them were identified as Aedes (Ochlerotatus) taeniorhynchus (Wiedemann, 1821), which were abundant in the salt marshes. We also collected Culex quinquefasciatus Say, 1823 close to human dwellings. Mitochondrial ND5 and COII gene sequences of Ae. taeniorhynchus were analyzed and compared to corresponding sequences of mosquitoes of the Galápagos Islands, Latin America, and the North American mainland. Aedes lineages from Socorro Island clustered most closely with a lineage from the continental U.S. Plasmodium spp. DNA was isolated from both species of mosquitoes. From 38 positive pools, we isolated 11 distinct mitochondrial Cytb lineages of Plasmodium spp. Seven of the Plasmodium lineages represent previously documented avian infective strains while four were new lineages. Our results confirm a potential risk for the spread of avian malaria and underscore the need to monitor both the mosquito and avian populations as a necessary conservation measure to protect endangered bird species on Socorro Island.

  11. Submicroscopic Plasmodium falciparum Infections Are Associated With Maternal Anemia, Premature Births, and Low Birth Weight.

    PubMed

    Cottrell, Gilles; Moussiliou, Azizath; Luty, Adrian J F; Cot, Michel; Fievet, Nadine; Massougbodji, Achille; Deloron, Philippe; Tuikue Ndam, Nicaise

    2015-05-15

    Molecular, as opposed to microscopic, detection measures the real prevalence of Plasmodium falciparum infections. Such occult infections are common during pregnancy but their impact on pregnancy outcomes is unclear. We performed a longitudinal study to describe that impact. In a cohort of 1037 Beninese pregnant women, we used ultrasound to accurately estimate gestational ages. Infection with P. falciparum, hemoglobin concentration, use of intermittent preventive treatment during pregnancy (IPTp) for malaria, and other parameters were recorded during pregnancy. Using multivariate analyses, we evaluated the impact of submicroscopic infections on maternal anemia, premature birth, and low birth weight. At inclusion, polymerase chain reaction (PCR) and microscopy detected infection in 40% and 16% of women, respectively. The proportion infected declined markedly after 2 doses of IPTp but rebounded to 34% (by PCR) at delivery. Submicroscopic infections during pregnancy were associated with lower mean hemoglobin irrespective of gravidity, and with increased anemia risk in primigravidae (odds ratio [OR], 2.23; 95% confidence interval [CI], .98-5.07). Prospectively, submicroscopic infections at inclusion were associated with significantly increased risks of low birth weight in primigravidae (OR, 6.09; 95% CI, 1.16-31.95) and premature births in multigravidae (OR, 2.25; 95% CI, 1.13-4.46). In this detailed longitudinal study, we document the deleterious impact of submicroscopic P. falciparum parasitemia during pregnancy on multiple pregnancy outcomes. Parasitemia occurs frequently during pregnancy, but routine microscopic and rapid diagnostic tests fail to detect the vast majority of episodes. Our findings imply caution in any revision of the current strategies for prevention of pregnancy-associated malaria. © The Author 2015. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e

  12. Anti-JK-a Antibody in a Case of SLE Patient with Plasmodium falciparum Malaria Infection.

    PubMed

    Datta, Suvro Sankha; Mukherjee, Somnath; Bhattacharya, Prasun; Mukherjee, Krishnendu

    2013-06-01

    A 58 year old lady presented with high grade fever, pallor, abdominal pain, loss of appetite and swelling of legs. She was subsequently diagnosed with SLE along with infection of Plasmodium falciparum malaria. She was clinically pale and advised for two units of packed red cell transfusion. One of the two units was incompatible, so only one unit was issued. Subsequently, DAT and auto control were positive. Later antibody specificity was identified, which came out to be anti JK-a. Because of recent transfusion 2 weeks back, her antigenic phenotype could not be elicited. Though we could not make out whether this antibody was the result of pregnancy or transfusion induced allo anti-JK-a or SLE induced auto anti JK-a, this antibody is highly clinically significant from transfusion point of view.

  13. Initiation of gametocytogenesis at very low parasite density in Plasmodium falciparum infection

    PubMed Central

    Farid, Ryan; Dixon, Matthew W.; Tilley, Leann

    2017-01-01

    Abstract The recent focus on the elimination of malaria has led to an increased interest in the role of sexual stages in its transmission. We introduce Plasmodium falciparum gametocyte exported protein-5 (PfGEXP5) transcript analysis as an important tool for evaluating the earliest (ring) stage sexual gametocytes in the blood of infected individuals. We show that gametocyte rings are detected in the peripheral blood immediately following establishment of asexual infections—without the need for triggers such as high-density asexual parasitemia or drug treatment. Committed gametocytes are refractory to the commonly used drug piperaquine, and mature gametocytes reappear in the bloodstream 10 days after the initial appearance of gametocyte rings. A further wave of commitment is observed following recrudescent asexual parasitemia, and these gametocytes are again refractory to piperaquine treatment. This work has implications for monitoring gametocyte and transmission dynamics and responses to drug treatment. PMID:28498997

  14. Analysis of Plasmodium falciparum diversity in natural infections by deep sequencing

    PubMed Central

    Manske, Magnus; Miotto, Olivo; Campino, Susana; Auburn, Sarah; Almagro-Garcia, Jacob; Maslen, Gareth; O’Brien, Jack; Djimde, Abdoulaye; Doumbo, Ogobara; Zongo, Issaka; Ouedraogo, Jean-Bosco; Michon, Pascal; Mueller, Ivo; Siba, Peter; Nzila, Alexis; Borrmann, Steffen; Kiara, Steven M.; Marsh, Kevin; Jiang, Hongying; Su, Xin-Zhuan; Amaratunga, Chanaki; Fairhurst, Rick; Socheat, Duong; Nosten, Francois; Imwong, Mallika; White, Nicholas J.; Sanders, Mandy; Anastasi, Elisa; Alcock, Dan; Drury, Eleanor; Oyola, Samuel; Quail, Michael A.; Turner, Daniel J.; Rubio, Valentin Ruano; Jyothi, Dushyanth; Amenga-Etego, Lucas; Hubbart, Christina; Jeffreys, Anna; Rowlands, Kate; Sutherland, Colin; Roper, Cally; Mangano, Valentina; Modiano, David; Tan, John C.; Ferdig, Michael T.; Amambua-Ngwa, Alfred; Conway, David J.; Takala-Harrison, Shannon; Plowe, Christopher V.; Rayner, Julian C.; Rockett, Kirk A.; Clark, Taane G.; Newbold, Chris I.; Berriman, Matthew; MacInnis, Bronwyn; Kwiatkowski, Dominic P.

    2013-01-01

    Malaria elimination strategies require surveillance of the parasite population for genetic changes that demand a public health response, such as new forms of drug resistance. 1,2 Here we describe methods for large-scale analysis of genetic variation in Plasmodium falciparum by deep sequencing of parasite DNA obtained from the blood of patients with malaria, either directly or after short term culture. Analysis of 86,158 exonic SNPs that passed genotyping quality control in 227 samples from Africa, Asia and Oceania provides genome-wide estimates of allele frequency distribution, population structure and linkage disequilibrium. By comparing the genetic diversity of individual infections with that of the local parasite population, we derive a metric of within-host diversity that is related to the level of inbreeding in the population. An open-access web application has been established for exploration of regional differences in allele frequency and of highly differentiated loci in the P. falciparum genome. PMID:22722859

  15. Intravital Placenta Imaging Reveals Microcirculatory Dynamics Impact on Sequestration and Phagocytosis of Plasmodium-Infected Erythrocytes

    PubMed Central

    de Moraes, Luciana Vieira; Tadokoro, Carlos Eduardo; Gómez-Conde, Iván; Olivieri, David N.; Penha-Gonçalves, Carlos

    2013-01-01

    Malaria in pregnancy is exquisitely aggressive, causing a range of adverse maternal and fetal outcomes prominently linked to Plasmodium-infected erythrocyte cytoadherence to fetal trophoblast. To elucidate the physiopathology of infected erythrocytes (IE) sequestration in the placenta we devised an experimental system for intravital placental examination of P. berghei-infected mice. BALB/c females were mated to C57Bl/6 CFP+ male mice and infected with GFP+ P. berghei IE, and at gestational day 18, placentas were exposed for time-lapse imaging acquisition under two-photon microscopy. Real-time images and quantitative measurements revealed that trophoblast conformational changes transiently restrain blood flow in the mouse placental labyrinth. The complex dynamics of placental microcirculation promotes IE accumulation in maternal blood spaces with low blood flow and allows the establishment of stable IE-trophoblast contacts. Further, we show that the fate of sequestered IE includes engulfment by both macrophagic and trophoblastic fetal-derived cells. These findings reinforce the current paradigm that IE interact with the trophoblast and provide definitive evidence on two novel pathogenesis mechanisms: (1) trophoblast layer controls placental microcirculation promoting IE sequestration; and (2) fetal-derived placental cells engulf sequestered IE. PMID:23382682

  16. Adherence of infected erythrocytes to venular endothelium selects for antigenic variants of Plasmodium falciparum.

    PubMed

    Biggs, B A; Anders, R F; Dillon, H E; Davern, K M; Martin, M; Petersen, C; Brown, G V

    1992-09-15

    Erythrocytes (E) infected with asexual forms of malaria parasites exhibit surface antigenic variation. In Plasmodium falciparum infections, the variant Ag is the P. falciparum E membrane protein 1 (PfEMP1). This molecule may also mediate the adherence of infected E to host venular endothelium. We show here that parasite lines selected for increased adherence to endothelial cells have undergone antigenic variation. Three adherent lines selected from the same P. falciparum clone reacted with the same agglutinating antiserum that failed to agglutinate the parental clone. Immunoprecipitation experiments with the agglutinating anti-serum demonstrated that the selected lines expressed cross-reactive forms of PfEMP1 that were of higher m.w. and antigenically distinct from PfEMP1 of the parental clone. When one of the adherent lines was cloned in the absence of selection, a range of variant antigenic types emerged with differing cytoadherence phenotypes. These findings show that selection for cytoadherence in vitro favors the emergence of antigenic variants of P. falciparum and suggest that the requirement for cytoadherence in vivo may restrict the range of antigenic variants of P. falciparum in natural infections.

  17. Food availability and competition do not modulate the costs of Plasmodium infection in dominant male canaries.

    PubMed

    Larcombe, Stephen; Bichet, Coraline; Cornet, Stéphane; Faivre, Bruno; Sorci, Gabriele

    2013-12-01

    Understanding the different factors that may influence parasite virulence is of fundamental interest to ecologists and evolutionary biologists. It has recently been demonstrated that parasite virulence may occur partly through manipulation of host competitive ability. Differences in competitive ability associated with the social status (dominant or subordinate) of a host may determine the extent of this competition-mediated parasite virulence. We proposed that differences between subordinate and dominant birds in the physiological costs of infection may change depending on the level of competition in social groups. We observed flocks of domestic canaries to determine dominant or subordinate birds, and modified competition by providing restricted (high competition) or ad libitum food (low competition). Entire flocks were then infected with either the avian malaria parasite, Plasmodium relictum or a control. Contrary to our predictions we found that the level of competition had no effect on the outcome of infection for dominant or subordinate birds. We found that dominant birds appeared to suffer greater infection mediated morbidity in both dietary treatments, with a higher and more sustained reduction in haematocrit, and higher parasitaemia, than subordinates. Our results show that dominance status in birds can certainly alter parasite virulence, though the links between food availability, competition, nutrition and virulence are likely to be complex and multifaceted.

  18. Comparison of Plasmodium falciparum infections in Panamanian and Colombian owl monkeys.

    PubMed

    Rossan, R N; Harper, J S; Davidson, D E; Escajadillo, A; Christensen, H A

    1985-11-01

    Parameters of blood-induced infections of the Vietnam Oak Knoll, Vietnam Smith, and Uganda Palo Alto strains of Plasmodium falciparum studied in 395 Panamanian owl monkeys in this laboratory between 1976-1984 were compared with those reported from another laboratory for 665 Colombian owl monkeys, studied between 1968-1975, and, at the time, designated Aotus trivirgatus griseimembra. The virulence of these strains was less in Panamanian than in Colombian owl monkeys, as indicated by lower mortality rates of the Panamanian monkeys during the first 30 days of patency. Maximum parasitemias of the Vietnam Smith and Uganda Palo Alto strain, in Panamanian owl monkeys dying during the first 15 days of patent infection, were significantly higher than in Colombian owl monkeys. Panamanian owl monkeys that survived the primary attack had significantly higher maximum parasitemias than the surviving Colombian owl monkeys. Peak parasitemias were attained significantly earlier after patency in Panamanian than in Colombian owl monkeys, irrespective of the strain of P. falciparum. More Panamanian than Colombian owl monkeys evidenced self-limited infection after the primary attack of either the Vietnam Smith or Uganda Palo Alto strain. The duration of the primary attacks and recrudescences were significantly shorter in Panamanian than in Colombian owl monkeys. Mean peak parasitemias during recrudescence were usually higher in Panamanian owl monkeys than in Colombian monkeys. Differences of infection parameters were probably attributable, in part, to geographical origin of the two monkey hosts and parasite strains.

  19. GLUT1‐mediated glucose uptake plays a crucial role during Plasmodium hepatic infection

    PubMed Central

    Meireles, Patrícia; Sales‐Dias, Joana; Andrade, Carolina M.; Mello‐Vieira, João; Mancio‐Silva, Liliana; Simas, J. Pedro; Staines, Henry M.

    2016-01-01

    Summary Intracellular pathogens have evolved mechanisms to ensure their survival and development inside their host cells. Here, we show that glucose is a pivotal modulator of hepatic infection by the rodent malaria parasite Plasmodium berghei and that glucose uptake via the GLUT1 transporter is specifically enhanced in P. berghei‐infected cells. We further show that ATP levels of cells containing developing parasites are decreased, which is known to enhance membrane GLUT1 activity. In addition, GLUT1 molecules are translocated to the membrane of the hepatic cell, increasing glucose uptake at later stages of infection. Chemical inhibition of GLUT1 activity leads to a decrease in glucose uptake and the consequent impairment of hepatic infection, both in vitro and in vivo. Our results reveal that changes in GLUT1 conformation and cellular localization seem to be part of an adaptive host response to maintain adequate cellular nutrition and energy levels, ensuring host cell survival and supporting P. berghei hepatic development. PMID:27404888

  20. Plasmodium falciparum infection rates for some Anopheles spp. from Guinea-Bissau, West Africa

    PubMed Central

    Sanford, Michelle R.; Cornel, Anthony J.; Nieman, Catelyn C.; Dinis, Joao; Marsden, Clare D.; Weakley, Allison M.; Han, Sarah; Rodrigues, Amabelia; Lanzaro, Gregory C.; Lee, Yoosook

    2014-01-01

    Presence of Plasmodium falciparum circumsporozoite protein (CSP) was detected by enzyme linked immunosorbent assay (ELISA) in a sample of Anopheles gambiae s.s., A. melas and A. pharoensis collected in Guinea-Bissau during October and November 2009. The percentage of P. falciparum infected samples (10.2% overall; confidence interval (CI): 7.45-13.6%) was comparable to earlier studies from other sites in Guinea-Bissau (9.6-12.4%). The majority of the specimens collected were identified as A. gambiae which had an individual infection rate of 12.6 % (CI: 8.88-17.6) across collection sites. A small number of specimens of A. coluzzii, A. coluzzii x A. gambiae hybrids, A. melas and A. pharoensis were collected and had infection rates of 4.3% (CI:0.98-12.4), 4.1% (CI:0.35-14.5), 11.1% (CI:1.86-34.1) and 33.3% (CI:9.25-70.4) respectively. Despite being present in low numbers in indoor collections, the exophilic feeding behaviors of A. melas (N=18) and A. pharoensis (N=6) and high infection rates observed in this survey suggest falciparum-malaria transmission potential outside of the protection of bed nets. PMID:25383188

  1. Optimization and inhibition of the adherent ability of Plasmodium falciparum-infected erythrocytes.

    PubMed

    Smith, H; Crandall, I; Prudhomme, J; Sherman, I W

    1992-01-01

    The vast majority of the 1-2 million malaria associated deaths that occur each year are due to anemia and cerebral malaria (the attachment of erythrocytes containing mature forms of Plasmodium falciparum to the endothelial cells that line the vascular beds of the brain). A "model system" for the study of cerebral malaria employs amelanotic melanoma cells as the "target" cells in an in vitro cytoadherence assay. Using this model system we determined that the optimum pH for adherence is 6.6 to 6.8, that high concentrations of Ca2+ (50mM) result in increased levels of binding, and that the type of buffer used influences adherence (Bis Tris > MOPS > HEPES > PIPES). We also observed that the ability of infected erythrocytes to cytoadhere varied from (erythrocyte) donor to donor. We have produced murine monoclonal antibodies against P. falciparum-infected red cells which recognize modified forms of human band 3; these inhibit the adherence of infected erythrocytes to melanoma cells in a dose-responsive fashion. Antimalarials (chloroquine, quinacrine, mefloquine, artemisinin), on the other hand, affected adherence in an indirect fashion i.e. since cytoadherence is due, in part, to the presence of knobs on the surface of the infected erythrocyte, and knob formation is dependent on intracellular parasite growth, when plasmodial development is inhibited so is knob production, and consequently adherence is ablated.

  2. Enhanced choline and Rb+ transport in human erythrocytes infected with the malaria parasite Plasmodium falciparum.

    PubMed Central

    Kirk, K; Wong, H Y; Elford, B C; Newbold, C I; Ellory, J C

    1991-01-01

    Human erythrocytes infected in vitro with the malaria parasite Plasmodium falciparum showed a markedly increased rate of choline influx compared with normal cells. Choline transport into uninfected cells (cultured in parallel with infected cells) obeyed Michaelis-Menten kinetics (Km approximately 11 microM). In malaria-parasite-infected cells there was an additional choline-transport component which failed to saturate at extracellular concentrations of up to 500 microM. This component was less sensitive than the endogenous transporter to inhibition by the Cinchona bark alkaloids quinine, quinidine, cinchonine and cinchonidine, but showed a much greater sensitivity than the native system to inhibition by piperine. The sensitivity of the induced choline transport to these reagents was similar to that of the malaria-induced (ouabain- and bumetanide-resistant) Rb(+)-transport pathway; however, the relative magnitudes of the piperine-sensitive choline and Rb+ fluxes in malaria-parasite-infected cells varied between cultures. This suggests either that the enhanced transport of the two cations was via functionally distinct (albeit pharmacologically similar) pathways, or that the transport was mediated by a pathway with variable substrate selectivity. PMID:1898345

  3. Exported Epoxide Hydrolases Modulate Erythrocyte Vasoactive Lipids during Plasmodium falciparum Infection

    PubMed Central

    Dalmia, Varun K.

    2016-01-01

    ABSTRACT Erythrocytes are reservoirs of important epoxide-containing lipid signaling molecules, including epoxyeicosatrienoic acids (EETs). EETs function as vasodilators and anti-inflammatory modulators in the bloodstream. Bioactive EETs are hydrolyzed to less active diols (dihydroxyeicosatrienoic acids) by epoxide hydrolases (EHs). The malaria parasite Plasmodium falciparum infects host red blood cells (RBCs) and exports hundreds of proteins into the RBC compartment. In this study, we show that two parasite epoxide hydrolases, P. falciparum epoxide hydrolases 1 (PfEH1) and 2 (PfEH2), both with noncanonical serine nucleophiles, are exported to the periphery of infected RBCs. PfEH1 and PfEH2 were successfully expressed in Escherichia coli, and they hydrolyzed physiologically relevant erythrocyte EETs. Mutations in active site residues of PfEH1 ablated the ability of the enzyme to hydrolyze an epoxide substrate. Overexpression of PfEH1 or PfEH2 in parasite-infected RBCs resulted in a significant alteration in the epoxide fatty acids stored in RBC phospholipids. We hypothesize that the parasite disruption of epoxide-containing signaling lipids leads to perturbed vascular function, creating favorable conditions for binding and sequestration of infected RBCs to the microvascular endothelium. PMID:27795395

  4. Competition between Plasmodium falciparum strains in clinical infections during in vitro culture adaptation.

    PubMed

    Chen, Kexuan; Sun, Ling; Lin, Yingxue; Fan, Qi; Zhao, Zhenjun; Hao, Mingming; Feng, Guohua; Wu, Yanrui; Cui, Liwang; Yang, Zhaoqing

    2014-06-01

    We evaluated the dynamics of parasite populations during in vitro culture adaptation in 15 mixed Plasmodium falciparum infections, which were collected from a hypoendemic area near the China-Myanmar border. Allele types at the msp1 block 2 in the initial clinical samples and during subsequent culture were quantified weekly using a quantitative PCR method. All mixed infections carried two allele types based on the msp1 genotyping result. We also genotyped several polymorphic sites in the dhfr, dhps and mdr1 genes on day 0 and day 28, which showed that most of the common sites analyzed were monomorphic. Two of the three clinical samples mixed at dhps 581 remained stable while one changed to wild-type during the culture. During in vitro culture, we observed a gradual loss of parasite populations with 10 of the 15 mixed infections becoming monoclonal by day 28 based on the msp1 allele type. In most cases, the more abundant msp1 allele types in the clinical blood samples at the beginning of culture became the sole or predominant allele types on day 28. These results suggest that some parasites may have growth advantages and the loss of parasite populations during culture adaptation of mixed infections may lead to biased results when comparing the phenotypes such as drug sensitivity of the culture-adapted parasites.

  5. Deconvolution of multiple infections in Plasmodium falciparum from high throughput sequencing data.

    PubMed

    Zhu, Sha Joe; Almagro-Garcia, Jacob; McVean, Gil

    2017-08-22

    The presence ofmultiple infecting strains of the malarial parasite Plasmodium falciparum affects key phenotypic traits, including drug resistance and risk of severe disease. Advances in protocols and sequencing technology have made it possible to obtain high-coverage genome-wide sequencing data from blood samples and blood spots taken in the field. However, analysing and interpreting such data is challenging because of the high rate of multiple infections present. We have developed a statistical method and implementation for deconvolving multiple genome sequences present in an individual with mixed infections. The software package DEploid uses haplotype structure within a reference panel of clonal isolates as a prior for haplotypes present in a given sample. It estimates the number of strains, their relative proportions and the haplotypes presented in a sample, allowing researchers to study multiple infection in malaria with an unprecedented level of detail. The open source implementation DEploid is freely available at https://github.com/mcveanlab/DEploid under the conditions of the GPLv3 license. An R version is available at https://github.com/mcveanlab/DEploid-r . joe.zhu@well.ox.ac.uk or mcvean@well.ox.ac.uk. Supplementary data are available at Bioinformatics online.

  6. GLUT1-mediated glucose uptake plays a crucial role during Plasmodium hepatic infection.

    PubMed

    Meireles, Patrícia; Sales-Dias, Joana; Andrade, Carolina M; Mello-Vieira, João; Mancio-Silva, Liliana; Simas, J Pedro; Staines, Henry M; Prudêncio, Miguel

    2017-02-01

    Intracellular pathogens have evolved mechanisms to ensure their survival and development inside their host cells. Here, we show that glucose is a pivotal modulator of hepatic infection by the rodent malaria parasite Plasmodium berghei and that glucose uptake via the GLUT1 transporter is specifically enhanced in P. berghei-infected cells. We further show that ATP levels of cells containing developing parasites are decreased, which is known to enhance membrane GLUT1 activity. In addition, GLUT1 molecules are translocated to the membrane of the hepatic cell, increasing glucose uptake at later stages of infection. Chemical inhibition of GLUT1 activity leads to a decrease in glucose uptake and the consequent impairment of hepatic infection, both in vitro and in vivo. Our results reveal that changes in GLUT1 conformation and cellular localization seem to be part of an adaptive host response to maintain adequate cellular nutrition and energy levels, ensuring host cell survival and supporting P. berghei hepatic development. © 2016 The Authors Cellular Microbiology Published by John Wiley & Sons Ltd.

  7. Antibodies against thrombospondin-related anonymous protein do not inhibit Plasmodium sporozoite infectivity in vivo.

    PubMed

    Gantt, S; Persson, C; Rose, K; Birkett, A J; Abagyan, R; Nussenzweig, V

    2000-06-01

    Thrombospondin-related anonymous protein (TRAP), a candidate malaria vaccine antigen, is required for Plasmodium sporozoite gliding motility and cell invasion. For the first time, the ability of antibodies against TRAP to inhibit sporozoite infectivity in vivo is evaluated in detail. TRAP contains an A-domain, a well-characterized adhesive motif found in integrins. We modeled here a three-dimensional structure of the TRAP A-domain of Plasmodium yoelii and located regions surrounding the MIDAS (metal ion-dependent adhesion site), the presumed business end of the domain. Mice were immunized with constructs containing these A-domain regions but were not protected from sporozoite challenge. Furthermore, monoclonal and rabbit polyclonal antibodies against the A-domain, the conserved N terminus, and the repeat region of TRAP had no effect on the gliding motility or sporozoite infectivity to mice. TRAP is located in micronemes, secretory organelles of apicomplexan parasites. Accordingly, the antibodies tested here stained cytoplasmic TRAP brightly by immunofluorescence. However, very little TRAP could be detected on the surface of sporozoites. In contrast, a dramatic relocalization of TRAP onto the parasite surface occurred when sporozoites were treated with calcium ionophore. This likely mimics the release of TRAP from micronemes when a sporozoite contacts its target cell in vivo. Contact with hepatoma cells in culture also appeared to induce the release of TRAP onto the surface of sporozoites. If large amounts of TRAP are released in close proximity to its cellular receptor(s), effective competitive inhibition by antibodies may be difficult to achieve.

  8. ParaSight-F rapid manual diagnostic test of Plasmodium falciparum infection.

    PubMed Central

    Uguen, C.; Rabodonirina, M.; De Pina, J. J.; Vigier, J. P.; Martet, G.; Maret, M.; Peyron, F.

    1995-01-01

    The ParaSight(R)-F test is a qualitative diagnostic test of Plasmodium falciparum, which is based on the detection by a monoclonal antibody of a species-specific soluble antigen (histidine-rich protein (HRP-II)) in whole blood and which can be performed without special equipment. A visual reading is given by a polyclonal antibody coupled with dye-loaded liposomes; when positive, a pink line appears. The test has been compared with microscopic examination of thin blood smears and with Quantitative Buffy Coat malaria test (QBC(R) in a single-blind study. A total of 358 patients who had returned to France from malarial areas and consulted their doctor with symptoms or for a routine examination were enrolled in the study; 33 of them were found to have a falciparum malaria infection by the diagnostic test. On the day of consultation, the specificity of the ParaSight(R)-F test was 99% and its sensitivity 94%. The follow-up of infected patients after treatment showed that the test became negative later than the other reference tests. There was no correlation between antigen persistence and the intensity of the ParaSight(R)-F signal or circulating parasitaemia. No cross-reaction was noted for seven malaria cases due to other Plasmodium species. The test was performed quickly (10 tests in 20 minutes), was easy to read, and required minimal space. For cases of imported malaria, the test's specificity and low threshold for detection could make it a valuable adjunct test. However, in its present form, it cannot replace microscopic techniques which are species-specific and quantitative. In endemic areas, the test seems to be very promising by its results and ease of use according to published field studies. Images Fig. 1 Fig. 2 PMID:8846490

  9. Antibodies against Thrombospondin-Related Anonymous Protein Do Not Inhibit Plasmodium Sporozoite Infectivity In Vivo

    PubMed Central

    Gantt, Soren; Persson, Cathrine; Rose, Keith; Birkett, Ashley J.; Abagyan, Ruben; Nussenzweig, Victor

    2000-01-01

    Thrombospondin-related anonymous protein (TRAP), a candidate malaria vaccine antigen, is required for Plasmodium sporozoite gliding motility and cell invasion. For the first time, the ability of antibodies against TRAP to inhibit sporozoite infectivity in vivo is evaluated in detail. TRAP contains an A-domain, a well-characterized adhesive motif found in integrins. We modeled here a three-dimensional structure of the TRAP A-domain of Plasmodium yoelii and located regions surrounding the MIDAS (metal ion-dependent adhesion site), the presumed business end of the domain. Mice were immunized with constructs containing these A-domain regions but were not protected from sporozoite challenge. Furthermore, monoclonal and rabbit polyclonal antibodies against the A-domain, the conserved N terminus, and the repeat region of TRAP had no effect on the gliding motility or sporozoite infectivity to mice. TRAP is located in micronemes, secretory organelles of apicomplexan parasites. Accordingly, the antibodies tested here stained cytoplasmic TRAP brightly by immunofluorescence. However, very little TRAP could be detected on the surface of sporozoites. In contrast, a dramatic relocalization of TRAP onto the parasite surface occurred when sporozoites were treated with calcium ionophore. This likely mimics the release of TRAP from micronemes when a sporozoite contacts its target cell in vivo. Contact with hepatoma cells in culture also appeared to induce the release of TRAP onto the surface of sporozoites. If large amounts of TRAP are released in close proximity to its cellular receptor(s), effective competitive inhibition by antibodies may be difficult to achieve. PMID:10816526

  10. Assessing parasite clearance during uncomplicated Plasmodium falciparum infection treated with artesunate monotherapy in Suriname

    PubMed Central

    Vreden, Stephen GS; Bansie, Rakesh D; Jitan, Jeetendra K; Adhin, Malti R

    2016-01-01

    Background Artemisinin resistance in Plasmodium falciparum is suspected when the day 3 parasitemia is >10% when treated with artemisinin-based combination therapy or if >10% of patients treated with artemisinin-based combination therapy or artesunate monotherapy harbored parasites with half-lives ≥5 hours. Hence, a single-arm prospective efficacy trial was conducted in Suriname for uncomplicated P. falciparum infection treated with artesunate-based monotherapy for 3 days assessing day 3 parasitemia, treatment outcome after 28 days, and parasite half-life. Methods The study was conducted in Paramaribo, the capital of Suriname, from July 2013 until July 2014. Patients with uncomplicated Plasmodium falciparum infection were included and received artesunate mono-therapy for three days. Day 3 parasitaemia, treatment outcome after 28 days and parasite half-life were determined. The latter was assessed with the parasite clearance estimator from the WorldWide Antimalarial Resistance Network (WWARN). Results Thirty-nine patients were included from July 2013 until July 2014. The day 3 parasitemia was 10%. Eight patients (20.5%) could be followed up until day 28 and showed adequate clinical and parasitological response. Parasite half-life could only be determined from ten data series (25.7%). The median parasite half-life was 5.16 hours, and seven of these data series had a half-life ≥5 hours, still comprising 17.9% of the total data series. Conclusion The low follow-up rate and the limited analyzable data series preclude clear conclusions about the efficacy of artesunate monotherapy in Suriname and the parasite half-life, respectively. The emergence of at least 17.9% of data series with a parasite half-life ≥5 hours supports the possible presence of artemisinin resistance. PMID:27920563

  11. Development of a Single Nucleotide Polymorphism Barcode to Genotype Plasmodium vivax Infections

    PubMed Central

    Baniecki, Mary Lynn; Faust, Aubrey L.; Schaffner, Stephen F.; Park, Daniel J.; Galinsky, Kevin; Daniels, Rachel F.; Hamilton, Elizabeth; Ferreira, Marcelo U.; Karunaweera, Nadira D.; Serre, David; Zimmerman, Peter A.; Sá, Juliana M.; Wellems, Thomas E.; Musset, Lise; Legrand, Eric; Melnikov, Alexandre; Neafsey, Daniel E.; Volkman, Sarah K.; Wirth, Dyann F.; Sabeti, Pardis C.

    2015-01-01

    Plasmodium vivax, one of the five species of Plasmodium parasites that cause human malaria, is responsible for 25–40% of malaria cases worldwide. Malaria global elimination efforts will benefit from accurate and effective genotyping tools that will provide insight into the population genetics and diversity of this parasite. The recent sequencing of P. vivax isolates from South America, Africa, and Asia presents a new opportunity by uncovering thousands of novel single nucleotide polymorphisms (SNPs). Genotyping a selection of these SNPs provides a robust, low-cost method of identifying parasite infections through their unique genetic signature or barcode. Based on our experience in generating a SNP barcode for P. falciparum using High Resolution Melting (HRM), we have developed a similar tool for P. vivax. We selected globally polymorphic SNPs from available P. vivax genome sequence data that were located in putatively selectively neutral sites (i.e., intergenic, intronic, or 4-fold degenerate coding). From these candidate SNPs we defined a barcode consisting of 42 SNPs. We analyzed the performance of the 42-SNP barcode on 87 P. vivax clinical samples from parasite populations in South America (Brazil, French Guiana), Africa (Ethiopia) and Asia (Sri Lanka). We found that the P. vivax barcode is robust, as it requires only a small quantity of DNA (limit of detection 0.3 ng/μl) to yield reproducible genotype calls, and detects polymorphic genotypes with high sensitivity. The markers are informative across all clinical samples evaluated (average minor allele frequency > 0.1). Population genetic and statistical analyses show the barcode captures high degrees of population diversity and differentiates geographically distinct populations. Our 42-SNP barcode provides a robust, informative, and standardized genetic marker set that accurately identifies a genomic signature for P. vivax infections. PMID:25781890

  12. Optimizing Intradermal Administration of Cryopreserved Plasmodium falciparum Sporozoites in Controlled Human Malaria Infection

    PubMed Central

    Lyke, Kirsten E.; Laurens, Matthew B.; Strauss, Kathy; Adams, Matthew; Billingsley, Peter F.; James, Eric; Manoj, Anita; Chakravarty, Sumana; Plowe, Christopher V.; Li, Ming Lin; Ruben, Adam; Edelman, Robert; Green, Michael; Dube, Tina J.; Kim Lee Sim, B.; Hoffman, Stephen L.

    2015-01-01

    Controlled human malaria infection (CHMI) is a powerful tool to evaluate malaria vaccine and prophylactic drug efficacy. Until recently CHMI was only carried out by the bite of infected mosquitoes. A parenteral method of CHMI would standardize Plasmodium falciparum sporozoite (PfSPZ) administration, eliminate the need for expensive challenge facility infrastructure, and allow for use of many P. falciparum strains. Recently, intradermal (ID) injection of aseptic, purified, cryopreserved PfSPZ was shown to induce P. falciparum malaria; however, 100% infection rates were not achieved by ID injection. To optimize ID PfSPZ dosing so as to achieve 100% infection, 30 adults aged 18–45 years were randomized to one of six groups composed of five volunteers each. The parameters of dose (1 × 104 versus 5 × 104 PfSPZ total dose per volunteer), number of injections (two versus eight), and aliquot volume per ID injection (10 μL versus 50 μL) were studied. Three groups attained 100% infection: 1 × 104 PfSPZ in 50 μL/2 doses, 1 × 104 PfSPZ in 10 μL/2 doses, and 5 × 104 PfSPZ in 10 μL/8 doses. The group that received 5 × 104 PfSPZ total dose in eight 10 μL injections had a 100% infection rate and the shortest prepatent period (mean of 12.7 days), approaching the prepatent period for the current CHMI standard of five infected mosquitoes. PMID:26416102

  13. Placental Microparticles and MicroRNAs in Pregnant Women with Plasmodium falciparum or HIV Infection

    PubMed Central

    Moro, Laura; Bardají, Azucena; Macete, Eusebio; Barrios, Diana; Morales-Prieto, Diana M.; España, Carolina; Mandomando, Inacio; Sigaúque, Betuel; Dobaño, Carlota; Markert, Udo R.; Benitez-Ribas, Daniel; Alonso, Pedro L.; Menéndez, Clara; Mayor, Alfredo

    2016-01-01

    Background During pregnancy, syncytiotrophoblast vesicles contribute to maternal tolerance towards the fetus, but also to pathologies such as pre-eclampsia. The aim of the study was to address whether Plasmodium falciparum and HIV infections in pregnancy affect the secretion, microRNA content and function of trophoblast microparticles. Methods Microparticles were isolated and characterized from 122 peripheral plasmas of Mozambican pregnant women, malaria- and/or HIV-infected and non-infected. Expression of placenta-related microRNAs in microparticles was analysed by qPCR and the effect of circulating microparticles on dendritic cells assessed by phenotype analysis and cytokine/chemokine measurement. Results Concentrations of total and trophoblast microparticles detected by flow cytometry were higher in HIV-positive (P = 0.005 and P = 0.030, respectively) compared to non-infected mothers, as well as in women delivering low birthweight newborns (P = 0.032 and P = 0.021, respectively). miR-517c was overexpressed in mothers with placental malaria (P = 0.034), compared to non-infected. Microparticles from HIV-positive induced a higher expression of MHCII (P = 0.021) and lower production of MCP1 (P = 0.008) than microparticles from non-infected women. Conclusions In summary, alterations in total and trophoblast microparticles associated with malaria and HIV in pregnant women may have an immunopathogenic role. The potential for placental-derived vesicles and microRNAs as biomarkers of adverse outcomes during pregnancy and malaria infection should be confirmed in future studies. PMID:26757431

  14. Optimizing Intradermal Administration of Cryopreserved Plasmodium falciparum Sporozoites in Controlled Human Malaria Infection.

    PubMed

    Lyke, Kirsten E; Laurens, Matthew B; Strauss, Kathy; Adams, Matthew; Billingsley, Peter F; James, Eric; Manoj, Anita; Chakravarty, Sumana; Plowe, Christopher V; Li, Ming Lin; Ruben, Adam; Edelman, Robert; Green, Michael; Dube, Tina J; Sim, B Kim Lee; Hoffman, Stephen L

    2015-12-01

    Controlled human malaria infection (CHMI) is a powerful tool to evaluate malaria vaccine and prophylactic drug efficacy. Until recently CHMI was only carried out by the bite of infected mosquitoes. A parenteral method of CHMI would standardize Plasmodium falciparum sporozoite (PfSPZ) administration, eliminate the need for expensive challenge facility infrastructure, and allow for use of many P. falciparum strains. Recently, intradermal (ID) injection of aseptic, purified, cryopreserved PfSPZ was shown to induce P. falciparum malaria; however, 100% infection rates were not achieved by ID injection. To optimize ID PfSPZ dosing so as to achieve 100% infection, 30 adults aged 18-45 years were randomized to one of six groups composed of five volunteers each. The parameters of dose (1 × 10(4) versus 5 × 10(4) PfSPZ total dose per volunteer), number of injections (two versus eight), and aliquot volume per ID injection (10 μL versus 50 μL) were studied. Three groups attained 100% infection: 1 × 10(4) PfSPZ in 50 μL/2 doses, 1 × 10(4) PfSPZ in 10 μL/2 doses, and 5 × 10(4) PfSPZ in 10 μL/8 doses. The group that received 5 × 10(4) PfSPZ total dose in eight 10 μL injections had a 100% infection rate and the shortest prepatent period (mean of 12.7 days), approaching the prepatent period for the current CHMI standard of five infected mosquitoes.

  15. Prevalence of malaria parasites (Plasmodium floridense and Plasmodium azurophilum) infecting a Puerto Rican lizard (Anolis gundlachi): a nine-year study.

    PubMed

    Schall, J J; Pearson, A R; Perkins, S L

    2000-06-01

    The prevalence of malaria parasites was studied in the lizard Anolis gundlachi over a 9-yr period at a site in the wet evergreen forest of eastern Puerto Rico. Three forms of the parasite infected the lizards; these were Plasmodium floridense, Plasmodium azurophilum in erythrocytes, and P. azurophilum in white blood cells. Overall prevalence of infection for 8 samples during the study period was significantly higher for males than females (32% of 3,296 males and 22% of 1,439 females). During the study, the site experienced substantial climatic and physical disturbance including rising temperature, droughts, and hurricanes that severely damaged the forest. Parasite prevalence in the first sample, 8 mo after the massive hurricane Hugo, was slightly, though significantly, lower than for subsequent samples. However, overall prevalence was stable during the 9-yr period. The results show malaria prevalence is more constant at the site than found for 2 studies in temperate forests, and that the Puerto Rico system may be an example of the stable, endemic malaria described by standard models for human malaria epidemiology.

  16. Invasive bacterial co-infection in African children with Plasmodium falciparum malaria: a systematic review.

    PubMed

    Church, James; Maitland, Kathryn

    2014-02-19

    Severe malaria remains a major cause of pediatric hospital admission across Africa. Invasive bacterial infection (IBI) is a recognized complication of Plasmodium falciparum malaria, resulting in a substantially worse outcome. Whether a biological relationship exists between malaria infection and IBI susceptibility remains unclear. We, therefore, examined the extent, nature and evidence of this association. We conducted a systematic search in August 2012 of three major scientific databases, PubMed, Embase and Africa Wide Information, for articles describing bacterial infection among children with P. falciparum malaria using the search string '(malaria OR plasmodium) AND (bacteria OR bacterial OR bacteremia OR bacteraemia OR sepsis OR septicaemia OR septicemia).' Eligiblity criteria also included studies of children hospitalized with malaria or outpatient attendances in sub-Saharan Africa. A total of 25 studies across 11 African countries fulfilled our criteria. They comprised twenty cohort analyses, two randomized controlled trials and three prospective epidemiological studies. In the meta-analysis of 7,208 children with severe malaria the mean prevalence of IBI was 6.4% (95% confidence interval (CI) 5.81 to 6.98%). In a further meta-analysis of 20,889 children hospitalised with all-severity malaria and 27,641 children with non-malarial febrile illness the mean prevalence of IBI was 5.58 (95% CI 5.5 to 5.66%) in children with malaria and 7.77% (95% CI 7.72 to 7.83%) in non-malaria illness. Ten studies reported mortality stratified by IBI. Case fatality was higher at 81 of 336, 24.1% (95% CI 18.9 to 29.4) in children with malaria/IBI co-infection compared to 585 of 5,760, 10.2% (95% CI 9.3 to 10.98) with malaria alone. Enteric gram-negative organisms were over-represented in malaria cases, non-typhoidal Salmonellae being the most commonest isolate. There was weak evidence indicating IBI was more common in the severe anemia manifestation of severe malaria. The

  17. Invasive bacterial co-infection in African children with Plasmodium falciparum malaria: a systematic review

    PubMed Central

    2014-01-01

    Background Severe malaria remains a major cause of pediatric hospital admission across Africa. Invasive bacterial infection (IBI) is a recognized complication of Plasmodium falciparum malaria, resulting in a substantially worse outcome. Whether a biological relationship exists between malaria infection and IBI susceptibility remains unclear. We, therefore, examined the extent, nature and evidence of this association. Methods We conducted a systematic search in August 2012 of three major scientific databases, PubMed, Embase and Africa Wide Information, for articles describing bacterial infection among children with P. falciparum malaria using the search string ‘(malaria OR plasmodium) AND (bacteria OR bacterial OR bacteremia OR bacteraemia OR sepsis OR septicaemia OR septicemia).’ Eligiblity criteria also included studies of children hospitalized with malaria or outpatient attendances in sub-Saharan Africa. Results A total of 25 studies across 11 African countries fulfilled our criteria. They comprised twenty cohort analyses, two randomized controlled trials and three prospective epidemiological studies. In the meta-analysis of 7,208 children with severe malaria the mean prevalence of IBI was 6.4% (95% confidence interval (CI) 5.81 to 6.98%). In a further meta-analysis of 20,889 children hospitalised with all-severity malaria and 27,641 children with non-malarial febrile illness the mean prevalence of IBI was 5.58 (95% CI 5.5 to 5.66%) in children with malaria and 7.77% (95% CI 7.72 to 7.83%) in non-malaria illness. Ten studies reported mortality stratified by IBI. Case fatality was higher at 81 of 336, 24.1% (95% CI 18.9 to 29.4) in children with malaria/IBI co-infection compared to 585 of 5,760, 10.2% (95% CI 9.3 to 10.98) with malaria alone. Enteric gram-negative organisms were over-represented in malaria cases, non-typhoidal Salmonellae being the most commonest isolate. There was weak evidence indicating IBI was more common in the severe anemia manifestation

  18. Evidence of non-Plasmodium falciparum malaria infection in Kédougou, Sénégal.

    PubMed

    Daniels, Rachel F; Deme, Awa Bineta; Gomis, Jules F; Dieye, Baba; Durfee, Katelyn; Thwing, Julie I; Fall, Fatou B; Ba, Mady; Ndiop, Medoune; Badiane, Aida S; Ndiaye, Yaye Die; Wirth, Dyann F; Volkman, Sarah K; Ndiaye, Daouda

    2017-01-03

    Expanded malaria control efforts in Sénégal have resulted in increased use of rapid diagnostic tests (RDT) to identify the primary disease-causing Plasmodium species, Plasmodium falciparum. However, the type of RDT utilized in Sénégal does not detect other malaria-causing species such as Plasmodium ovale spp., Plasmodium malariae, or Plasmodium vivax. Consequently, there is a lack of information about the frequency and types of malaria infections occurring in Sénégal. This study set out to better determine whether species other than P. falciparum were evident among patients evaluated for possible malaria infection in Kédougou, Sénégal. Real-time polymerase chain reaction speciation assays for P. vivax, P. ovale spp., and P. malariae were developed and validated by sequencing and DNA extracted from 475 Plasmodium falciparum-specific HRP2-based RDT collected between 2013 and 2014 from a facility-based sample of symptomatic patients from two health clinics in Kédougou, a hyper-endemic region in southeastern Sénégal, were analysed. Plasmodium malariae (n = 3) and P. ovale wallikeri (n = 2) were observed as co-infections with P. falciparum among patients with positive RDT results (n = 187), including one patient positive for all three species. Among 288 negative RDT samples, samples positive for P. falciparum (n = 24), P. ovale curtisi (n = 3), P. ovale wallikeri (n = 1), and P. malariae (n = 3) were identified, corresponding to a non-falciparum positivity rate of 2.5%. These findings emphasize the limitations of the RDT used for malaria diagnosis and demonstrate that non-P. falciparum malaria infections occur in Sénégal. Current RDT used for routine clinical diagnosis do not necessarily provide an accurate reflection of malaria transmission in Kédougou, Sénégal, and more sensitive and specific methods are required for diagnosis and patient care, as well as surveillance and elimination activities. These findings have implications for other

  19. Prevalence of PCR detectable malaria infection among febrile patients with a negative Plasmodium falciparum specific rapid diagnostic test in Zanzibar.

    PubMed

    Baltzell, Kimberly A; Shakely, Deler; Hsiang, Michelle; Kemere, Jordan; Ali, Abdullah Suleiman; Björkman, Anders; Mårtensson, Andreas; Omar, Rahila; Elfving, Kristina; Msellem, Mwinyi; Aydin-Schmidt, Berit; Rosenthal, Philip J; Greenhouse, Bryan

    2013-02-01

    We screened for malaria in 594 blood samples from febrile patients who tested negative by a Plasmodium falciparum-specific histidine-rich protein-2-based rapid diagnostic test at 12 health facilities in Zanzibar districts North A and Micheweni, from May to August 2010. Screening was with microscopy, polymerase chain reaction (PCR) targeting the cytochrome b gene (cytbPCR) of the four major human malaria species, and quantitative PCR (qPCR). The prevalence of cytbPCR-detectable malaria infection was 2% (12 of 594), including 8 P. falciparum, 3 Plasmodium malariae, and 1 Plasmodium vivax infections. Microscopy identified 4 of 8 P. falciparum infections. Parasite density as estimated by microscopy or qPCR was > 4,000 parasites/μL in 5 of 8 cytbPCR-detectable P. falciparum infections. The infections that were missed by the rapid diagnostic test represent a particular challenge in malaria elimination settings and highlight the need for more sensitive point-of-care diagnostic tools to improve case detection of all human malaria species in febrile patients.

  20. Platelets activate a pathogenic response to blood-stage Plasmodium infection but not a protective immune response.

    PubMed

    Gramaglia, Irene; Velez, Joyce; Combes, Valery; Grau, Georges E R; Wree, Melanie; van der Heyde, Henri C

    2017-03-23

    Clinical studies indicate that thrombocytopenia correlates with the development of severe falciparum malaria, suggesting that platelets either contribute to control of parasite replication, possibly as innate parasite killer cells or function in eliciting pathogenesis. Removal of platelets by anti-CD41 mAb treatment, platelet inhibition by aspirin, and adoptive transfer of wild-type (WT) platelets to CD40-KO mice, which do not control parasite replication, resulted in similar parasitemia compared with control mice. Human platelets at a physiologic ratio of 1 platelet to 9 red blood cells (RBCs) did not inhibit the in vitro development or replication of blood-stage Plasmodium falciparum The percentage of Plasmodium-infected (iRBCs) with bound platelets during the ascending parasitemia in Plasmodium chabaudi- and Plasmodium berghei-infected mice and the 48-hour in vitro cycle of P falciparum was <10%. P chabaudi and P berghei iRBCs with apoptotic parasites (TdT(+)) exhibited minimal platelet binding (<5%), which was similar to nonapoptotic iRBCs. These findings collectively indicate platelets do not kill bloodstage Plasmodium at physiologically relevant effector-to-target ratios. P chabaudi primary and secondary parasitemia was similar in mice depleted of platelets by mAb-injection just before infection, indicating that activation of the protective immune response does not require platelets. In contrast to the lack of an effect on parasite replication, adoptive transfer of WT platelets to CD40-KO mice, which are resistant to experimental cerebral malaria, partially restored experimental cerebral malaria mortality and symptoms in CD40-KO recipients, indicating platelets elicit pathogenesis and platelet CD40 is a key molecule. © 2017 by The American Society of Hematology.

  1. Plasmodium falciparum Infection Does Not Affect Human Immunodeficiency Virus Viral Load in Coinfected Rwandan Adults

    PubMed Central

    Subramaniam, Krishanthi; Plank, Rebeca M.; Lin, Nina; Goldman-Yassen, Adam; Ivan, Emil; Becerril, Carlos; Kemal, Kimdar; Heo, Moonseong; Keller, Marla J.; Mutimura, Eugene; Anastos, Kathryn; Daily, Johanna P.

    2014-01-01

    Background  Plasmodium falciparum infection has been reported to increase human immunodeficiency virus (HIV) viral load (VL), which can facilitate HIV transmission. We prospectively studied the impact of mild P falciparum coinfection on HIV VL in Rwanda. Methods  We measured plasma HIV VL at presentation with malaria infection and weekly for 4 weeks after artemether-lumefantrine treatment in Rwandan adults infected with HIV with P falciparum malaria. Regression analyses were used to examine associations between malaria infection and HIV VL changes. Samples with detectable virus underwent genotypic drug-resistance testing. Results  We enrolled 28 HIV-malaria coinfected patients and observed 27 of them for 5 weeks. Three patients (11%) were newly diagnosed with HIV. Acute P falciparum infection had no significant effect on HIV VL slope over 28 days of follow-up. Ten patients with VL <40 copies/mL at enrollment maintained viral suppression throughout. Seventeen patients had a detectable VL at enrollment including 9 (53%) who reported 100% adherence to ARVs; 3 of these had detectable genotypic drug resistance. Conclusions  Unlike studies from highly malaria-endemic areas, we did not identify an effect of P falciparum infection on HIV VL; therefore, malaria is not likely to increase HIV-transmission risk in our setting. However, routine HIV testing should be offered to adults presenting with acute malaria in Rwanda. Most importantly, we identified a large percentage of patients with detectable HIV VL despite antiretroviral (ARV) therapy. Some of these patients had HIV genotypic drug resistance. Larger studies are needed to define the prevalence and factors associated with detectable HIV VL in patients prescribed ARVs in Rwanda. PMID:25734136

  2. Treatment uptake by individuals infected with Plasmodium falciparum in rural Gambia, West Africa.

    PubMed Central

    von Seidlein, Lorenz; Clarke, Sian; Alexander, Neâl; Manneh, Fandingding; Doherty, Tom; Pinder, Margaret; Walraven, Gijs; Greenwood, Brian

    2002-01-01

    OBJECTIVE: To find out what proportion of Plasmodium falciparum infections are treated in rural Gambia. METHODS: Subjects from four villages in the Gambia were followed over nine months through visits to village health workers. Monthly cross-sectional malaria surveys measured the prevalence of P. falciparum infection. Linked databases were searched for treatment requests. Treated cases were individuals with parasitaemia who requested treatment during narrow or extended periods (14 or 28 days, respectively) before or after a positive blood film was obtained. FINDINGS: Parasite prevalence peaked in November 1998, when 399/653 (61%) individuals had parasitaemia. Parasite prevalence was highest throughout the study in children aged 5-10 years. Although access to treatment was better than in most of sub-Saharan Africa, only 20% of infected individuals sought medical treatment up to 14 days before or after a positive blood film. Within two months of a positive blood film, 199/726 (27%) individuals with parasitaemia requested treatment. Despite easy access to health care, less than half (42%) of those with parasite densities consistent with malaria attacks (5000/ l) requested treatment. High parasite density and infection during October-November were associated with more frequent treatment requests. Self-treatment was infrequent in study villages: in 3/120 (2.5%) households antimalarial drugs had been used in the preceding malaria season. CONCLUSION: Many P. falciparum infections may be untreated because of their subclinical nature. Intermittent presumptive treatment may reduce morbidity and mortality. It is likely that not all untreated infections were asymptomatic. Qualitative research should explore barriers to treatment uptake, to allow educational interventions to be planned. PMID:12471399

  3. Plasmodium falciparum Infection Does Not Affect Human Immunodeficiency Virus Viral Load in Coinfected Rwandan Adults.

    PubMed

    Subramaniam, Krishanthi; Plank, Rebeca M; Lin, Nina; Goldman-Yassen, Adam; Ivan, Emil; Becerril, Carlos; Kemal, Kimdar; Heo, Moonseong; Keller, Marla J; Mutimura, Eugene; Anastos, Kathryn; Daily, Johanna P

    2014-09-01

    Plasmodium falciparum infection has been reported to increase human immunodeficiency virus (HIV) viral load (VL), which can facilitate HIV transmission. We prospectively studied the impact of mild P falciparum coinfection on HIV VL in Rwanda. We measured plasma HIV VL at presentation with malaria infection and weekly for 4 weeks after artemether-lumefantrine treatment in Rwandan adults infected with HIV with P falciparum malaria. Regression analyses were used to examine associations between malaria infection and HIV VL changes. Samples with detectable virus underwent genotypic drug-resistance testing. We enrolled 28 HIV-malaria coinfected patients and observed 27 of them for 5 weeks. Three patients (11%) were newly diagnosed with HIV. Acute P falciparum infection had no significant effect on HIV VL slope over 28 days of follow-up. Ten patients with VL <40 copies/mL at enrollment maintained viral suppression throughout. Seventeen patients had a detectable VL at enrollment including 9 (53%) who reported 100% adherence to ARVs; 3 of these had detectable genotypic drug resistance. Unlike studies from highly malaria-endemic areas, we did not identify an effect of P falciparum infection on HIV VL; therefore, malaria is not likely to increase HIV-transmission risk in our setting. However, routine HIV testing should be offered to adults presenting with acute malaria in Rwanda. Most importantly, we identified a large percentage of patients with detectable HIV VL despite antiretroviral (ARV) therapy. Some of these patients had HIV genotypic drug resistance. Larger studies are needed to define the prevalence and factors associated with detectable HIV VL in patients prescribed ARVs in Rwanda.

  4. A kinetic fluorescence assay reveals unusual features of Ca++ uptake in Plasmodium falciparum-infected erythrocytes

    PubMed Central

    2014-01-01

    Background To facilitate development within erythrocytes, malaria parasites increase their host cell uptake of diverse solutes including Ca++. The mechanism and molecular basis of increased Ca++ permeability remains less well studied than that of other solutes. Methods Based on an appropriate Ca++ affinity and its greater brightness than related fluorophores, Fluo-8 was selected and used to develop a robust fluorescence-based assay for Ca++ uptake by human erythrocytes infected with Plasmodium falciparum. Results Both uninfected and infected cells exhibited a large Ca++-dependent fluorescence signal after loading with the Fluo-8 dye. Probenecid, an inhibitor of erythrocyte organic anion transporters, abolished the fluorescence signal in uninfected cells; in infected cells, this agent increased fluorescence via mechanisms that depend on parasite genotype. Kinetic fluorescence measurements in 384-well microplates revealed that the infected cell Ca++ uptake is not mediated by the plasmodial surface anion channel (PSAC), a parasite nutrient channel at the host membrane; it also appears to be distinct from mammalian Ca++ channels. Imaging studies confirmed a low intracellular Ca++ in uninfected cells and higher levels in both the host and parasite compartments of infected cells. Parasite growth inhibition studies revealed a conserved requirement for extracellular Ca++. Conclusions Nondestructive loading of Fluo-8 into human erythrocytes permits measurement of Ca++ uptake kinetics. The greater Ca++ permeability of cells infected with malaria parasites is apparent when probenecid is used to inhibit Fluo-8 efflux at the host membrane. This permeability is mediated by a distinct pathway and may be essential for intracellular parasite development. The miniaturized assay presented here should help clarify the precise transport mechanism and may identify inhibitors suitable for antimalarial drug development. PMID:24885754

  5. Characteristic age distribution of Plasmodium vivax infections after malaria elimination on Aneityum Island, Vanuatu.

    PubMed

    Kaneko, Akira; Chaves, Luis F; Taleo, George; Kalkoa, Morris; Isozumi, Rie; Wickremasinghe, Renu; Perlmann, Hedvig; Takeo, Satoru; Tsuboi, Takafumi; Tachibana, Shin-ichiro; Kimura, Masatsugu; Björkman, Anders; Troye-Blomberg, Marita; Tanabe, Kazuyuki; Drakeley, Chris

    2014-01-01

    Resurgence is a major concern after malaria elimination. After the initiation of the elimination program on Aneityum Island in 1991, microscopy showed that Plasmodium falciparum disappeared immediately, whereas P. vivax disappeared from 1996 onward, until P. vivax cases were reported in January 2002. By conducting malariometric surveys of the entire population of Aneityum, we investigated the age distribution of individuals with parasites during this epidemic in the context of antimalarial antibody levels and parasite antigen diversity. In July 2002, P. vivax infections were detected by microscopy in 22/759 individuals: 20/298 born after the beginning of the elimination program in 1991, 2/126 born between 1982 and 1991, and none of 335 born before 1982. PCR increased the number of infections detected to 77, distributed among all age groups. Prevalences were 12.1%, 16.7%, and 6.0%, respectively (P < 0.001). In November, a similar age pattern was found, but with fewer infections: 6/746 and 39/741 individuals were found to be infected by microscopy and PCR, respectively. The frequencies of antibody responses to P. vivax were significantly higher in individuals born before 1991 than in younger age groups and were similar to those on Malakula Island, an area of endemicity. Remarkably low antigen diversity (h, 0.15) of P. vivax infections was observed on Aneityum compared with the other islands (h, 0.89 to 1.0). A P. vivax resurgence was observed among children and teenagers on Aneityum, an age distribution similar to those before elimination and on islands where P. vivax is endemic, suggesting that in the absence of significant exposure, immunity may persist, limiting infection levels in adults. The limited parasite gene pool on islands may contribute to this protection.

  6. Plasmodium falciparum Antigens on the Surface of the Gametocyte-Infected Erythrocyte

    PubMed Central

    Saeed, Maha; Roeffen, Will; Alexander, Neal; Drakeley, Christopher J.; Targett, Geoffrey A. T.; Sutherland, Colin J.

    2008-01-01

    Background The asexual blood stages of the human malaria parasite Plasmodium falciparum produce highly immunogenic polymorphic antigens that are expressed on the surface of the host cell. In contrast, few studies have examined the surface of the gametocyte-infected erythrocyte. Methodology/Principal Findings We used flow cytometry to detect antibodies recognising the surface of live cultured erythrocytes infected with gametocytes of P. falciparum strain 3D7 in the plasma of 200 Gambian children. The majority of children had been identified as carrying gametocytes after treatment for malaria, and each donated blood for mosquito-feeding experiments. None of the plasma recognised the surface of erythrocytes infected with developmental stages of gametocytes (I–IV), but 66 of 194 (34.0%) plasma contained IgG that recognised the surface of erythrocytes infected with mature (stage V) gametocytes. Thirty-four (17.0%) of 200 plasma tested recognised erythrocytes infected with trophozoites and schizonts, but there was no association with recognition of the surface of gametocyte-infected erythrocytes (odds ratio 1.08, 95% C.I. 0.434–2.57; P = 0.851). Plasma antibodies with the ability to recognise gametocyte surface antigens (GSA) were associated with the presence of antibodies that recognise the gamete antigen Pfs 230, but not Pfs48/45. Antibodies recognising GSA were associated with donors having lower gametocyte densities 4 weeks after antimalarial treatment. Conclusions/Significance We provide evidence that GSA are distinct from antigens detected on the surface of asexual 3D7 parasites. Our findings suggest a novel strategy for the development of transmission-blocking vaccines. PMID:18509532

  7. Febrile temperatures induce cytoadherence of ring-stage Plasmodium falciparum-infected erythrocytes.

    PubMed

    Udomsangpetch, Rachanee; Pipitaporn, Busaba; Silamut, Kamolrat; Pinches, Robert; Kyes, Sue; Looareesuwan, Sornchai; Newbold, Christopher; White, Nicholas J

    2002-09-03

    In falciparum malaria, the malaria parasite induces changes at the infected red blood cell surface that lead to adherence to vascular endothelium and other red blood cells. As a result, the more mature stages of Plasmodium falciparum are sequestered in the microvasculature and cause vital organ dysfunction, whereas the ring stages circulate in the blood stream. Malaria is characterized by fever. We have studied the effect of febrile temperatures on the cytoadherence in vitro of P. falciparum-infected erythrocytes. Freshly obtained ring-stage-infected red blood cells from 10 patients with acute falciparum malaria did not adhere to the principle vascular adherence receptors CD36 or intercellular adhesion molecule-1 (ICAM-1). However, after a brief period of heating to 40 degrees C, all ring-infected red blood cells adhered to CD36, and some isolates adhered to ICAM-1, whereas controls incubated at 37 degrees C did not. Heating to 40 degrees C accelerated cytoadherence and doubled the maximum cytoadherence observed (P < 0.01). Erythrocytes infected by ring-stages of the ICAM-1 binding clone A4var also did not cytoadhere at 37 degrees C, but after heating to febrile temperatures bound to both CD36 and ICAM-1. Adherence of red blood cells infected with trophozoites was also increased considerably by brief heating. The factor responsible for heat induced adherence was shown to be the parasite derived variant surface protein PfEMP-1. RNA analysis showed that levels of var mRNA did not differ between heated and unheated ring-stage parasites. Thus fever-induced adherence appeared to involve increased trafficking of PfEMP-1 to the erythrocyte membrane. Fever induced cytoadherence is likely to have important pathological consequences and may explain both clinical deterioration with fever in severe malaria and the effects of antipyretics on parasite clearance.

  8. Molecular Evidence of High Proportion of Plasmodium vivax Malaria Infection in White Nile Area in Sudan

    PubMed Central

    Suliman, Makarim M. Adam; Hamad, Bushra M.; Albasheer, Musab M. Ali; Elhadi, Maytha; Elobied, Maha

    2016-01-01

    Plasmodium falciparum is a predominant malaria species that infects humans in the African continent. A recent WHO report estimated 95% and 5% of P. falciparum and P. vivax malaria cases, respectively, in Sudan. However many laboratory reports from different areas in Sudan indicated otherwise. In order to verify, we selected four hundred suspected malaria cases from Aljabalain area located in the White Nile state, central Sudan, and diagnosed them with quality insured microscopy and species-specific nested PCR. Our results indicated that the proportion of P. vivax infections among suspected malaria cases was high. We found that on average 20% and 36.5% of malaria infections in both study areas were caused by P. vivax using both microscopy and PCR, respectively. This change in pattern is likely due to the recent demographic changes and high rate of immigration from neighbouring countries in the recent years. This is the first extensive clinical study of its kind that shows rising trend in P. vivax malaria cases in White Nile area, Sudan. PMID:27980861

  9. Toxicity evaluation of artesunate and artelinate in Plasmodium berghei-infected and uninfected rats.

    PubMed

    Li, Qigui; Xie, Lisa H; Johnson, Todd O; Si, Yuanzheng; Haeberle, Adam S; Weina, Peter J

    2007-02-01

    A recent therapeutic index study in rats demonstrated that i.v. artesunate (AS) is safer than artelinate (AL). The present study of acute toxicity illustrated an LD(50) of 177 mg/kg and 488 mg/kg for AL and AS, respectively, following daily i.v. injection for 3 days in Plasmodium berghei-infected rats. In uninfected rats, the LD(50) values were 116 mg/kg and 351 mg/kg after a single dose of AL and AS, respectively. This study showed vascular necrosis in 50% of the animals at 13.5 mg/kg AL and at 42.8 mg/kg AS. Animals also showed moderate signs of renal failure at 40 mg/kg AL and 240 mg/kg AS (100 times higher than the therapeutic dose). Histopathological evaluation demonstrated mild to moderate tubular necrosis in uninfected rats treated with 40 mg/kg AL and 240 mg/kg AS; interestingly, fewer pathological lesions were observed in malaria-infected rats. Renal injury was reversible in all cases by Day 8 after cessation of dosing. No neurotoxicity was seen in any case with all i.v. regimens. In conclusion, AL and AS exhibit less toxic effects in P. berghei-infected rats than in uninfected rats. Both agents caused irreversible vascular irritation, reversible nephrotoxicity and no neurotoxicity at high doses. The data indicate that AS is three times safer than AL in rats.

  10. Malaria’s Deadly Grip: Cytoadhesion of Plasmodium falciparum Infected Erythrocytes

    PubMed Central

    Smith, Joseph D.; Rowe, J. Alexandra; Higgins, Matthew K.; Lavstsen, Thomas

    2013-01-01

    Summary Cytoadhesion of Plasmodium falciparum infected erythrocytes to host microvasculature is a key virulence determinant. Parasite binding is mediated by a large family of clonally variant adhesion proteins, termed P. falciparum erythrocyte membrane protein 1 (PfEMP1), encoded by var genes and expressed at the infected-erythrocyte surface. Although PfEMP1 proteins have extensively diverged under opposing selection pressure to maintain ligand binding while avoiding antibody-mediated detection, recent work has revealed they can be classified into different groups based on chromosome location and domain composition. This grouping reflects functional specialization of PfEMP1 proteins for different human host and microvascular binding niches and appears to be maintained by gene recombination hierarchies. In one extreme, a specific PfEMP1 variant is associated with placental binding and malaria during pregnancy, while other PfEMP1 subtypes appear to be specialized for infection of malaria naïve hosts. Here, we discuss recent findings on the origins and evolution of the var gene family, the structure-function of PfEMP1 proteins, and a distinct subset of PfEMP1 variants that have been associated with severe childhood malaria. PMID:23957661

  11. In vivo Antimalarial Activities of Russelia Equisetiformis in Plasmodium Berghei Infected Mice

    PubMed Central

    Ojurongbe, O.; Ojo, J. A.; Adefokun, D. I.; Abiodun, O. O.; Odewale, G.; Awe, E. O.

    2015-01-01

    The rising problem of resistance to most commonly used antimalarials remains a major challenge in the control of malaria suggesting the need for new antimalarial agents. This work explores the antiplasmodial potential of ethanol extract of Russelia equisetiformis in chloroquine Plasmodium berghei infected mice. Swiss albino mice were intraperitoneally infected with chloroquine-resistant P. berghei (ANKA). Experimental mice were treated for four days consecutively with graded doses of plant extracts and standard antimalarial drugs (artesunate and chloroquine) at a dose of 10 mg/kg body weight used as control. The extract showed a dose-dependent activity in the chemosuppression of P. berghei parasites by 31.6, 44.7, 48.4 and 86.5% at doses of 100, 200, 400 and 800 mg/kg, while chloroquine (10 mg/kg) and artesunate produced 59.4 and 68.4%, respectively. The extract showed a significant decrease in parasitaemia (P<0.05). The level of parasitemia and decrease in weight in all the treated groups was significantly lower (P<0.05) compared with the infected but untreated mice. The plant extract was devoid of toxicity at the highest dose tested (5000 mg/kg). The study concluded that the ethanol extract of R. equisetiformis possesses antimalarial effect, which supports the folk medicine claim of its use in the treatment of malaria. PMID:26664070

  12. Estimating Geographical Variation in the Risk of Zoonotic Plasmodium knowlesi Infection in Countries Eliminating Malaria.

    PubMed

    Shearer, Freya M; Huang, Zhi; Weiss, Daniel J; Wiebe, Antoinette; Gibson, Harry S; Battle, Katherine E; Pigott, David M; Brady, Oliver J; Putaporntip, Chaturong; Jongwutiwes, Somchai; Lau, Yee Ling; Manske, Magnus; Amato, Roberto; Elyazar, Iqbal R F; Vythilingam, Indra; Bhatt, Samir; Gething, Peter W; Singh, Balbir; Golding, Nick; Hay, Simon I; Moyes, Catherine L

    2016-08-01

    Infection by the simian malaria parasite, Plasmodium knowlesi, can lead to severe and fatal disease in humans, and is the most common cause of malaria in parts of Malaysia. Despite being a serious public health concern, the geographical distribution of P. knowlesi malaria risk is poorly understood because the parasite is often misidentified as one of the human malarias. Human cases have been confirmed in at least nine Southeast Asian countries, many of which are making progress towards eliminating the human malarias. Understanding the geographical distribution of P. knowlesi is important for identifying areas where malaria transmission will continue after the human malarias have been eliminated. A total of 439 records of P. knowlesi infections in humans, macaque reservoir and vector species were collated. To predict spatial variation in disease risk, a model was fitted using records from countries where the infection data coverage is high. Predictions were then made throughout Southeast Asia, including regions where infection data are sparse. The resulting map predicts areas of high risk for P. knowlesi infection in a number of countries that are forecast to be malaria-free by 2025 (Malaysia, Cambodia, Thailand and Vietnam) as well as countries projected to be eliminating malaria (Myanmar, Laos, Indonesia and the Philippines). We have produced the first map of P. knowlesi malaria risk, at a fine-scale resolution, to identify priority areas for surveillance based on regions with sparse data and high estimated risk. Our map provides an initial evidence base to better understand the spatial distribution of this disease and its potential wider contribution to malaria incidence. Considering malaria elimination goals, areas for prioritised surveillance are identified.

  13. Diagnosis of Plasmodium falciparum infection in man: detection of parasite antigens by ELISA*

    PubMed Central

    Mackey, L. J.; McGregor, I. A.; Paounova, N.; Lambert, P. H.

    1982-01-01

    An ELISA method has been developed for the diagnosis of Plasmodium falciparum infection in man. Parasites from in vitro cultures of P. falciparum were used as source of antigen for the solid phase and the source of specific antibody was immune Gambian sera; binding of antibody in antigen-coated wells was registered by means of alkaline phosphatase-conjugated anti-human IgG. Parasites were detected on the basis of inhibition of antibody-binding. The test was applied to the detection of parasites in human red blood cells (RBC) from in vitro cultures of P. falciparum and in RBC from infected Gambians; RBC from 100 Geneva blood donors served as normal, uninfected controls. In titration experiments, the degree of antibody-binding inhibition correlated with the number of parasites in the test RBC. Parasites were detected at a level of 8 parasites/106 RBC. Samples of RBC were tested from 126 Gambians with microscopically proven infection; significant antibody-binding inhibition was found in 86% of these cases, where parasitaemia ranged from 10 to 125 000/μl of blood. The presence of high-titre antibody in the test preparations was found to reduce the sensitivity of parasite detection in infected RBC from in vitro cultures mixed with equal volumes of different antibody-containing sera. The sensitivity was restored in most cases by recovering the RBC by centrifugation before testing. In a preliminary experiment, there was no significant difference in antibody-binding inhibition using fresh infected RBC and RBC dried on filter-paper and recovered by elution, although there was greater variation in the latter samples. PMID:7044589

  14. Diagnosis of Plasmodium falciparum infection in man: detection of parasite antigens by ELISA.

    PubMed

    Mackey, L J; McGregor, I A; Paounova, N; Lambert, P H

    1982-01-01

    An ELISA method has been developed for the diagnosis of Plasmodium falciparum infection in man. Parasites from in vitro cultures of P. falciparum were used as source of antigen for the solid phase and the source of specific antibody was immune Gambian sera; binding of antibody in antigen-coated wells was registered by means of alkaline phosphatase-conjugated anti-human IgG. Parasites were detected on the basis of inhibition of antibody-binding. The test was applied to the detection of parasites in human red blood cells (RBC) from in vitro cultures of P. falciparum and in RBC from infected Gambians; RBC from 100 Geneva blood donors served as normal, uninfected controls. In titration experiments, the degree of antibody-binding inhibition correlated with the number of parasites in the test RBC. Parasites were detected at a level of 8 parasites/10(6) RBC. Samples of RBC were tested from 126 Gambians with microscopically proven infection; significant antibody-binding inhibition was found in 86% of these cases, where parasitaemia ranged from 10 to 125 000/mul of blood. The presence of high-titre antibody in the test preparations was found to reduce the sensitivity of parasite detection in infected RBC from in vitro cultures mixed with equal volumes of different antibody-containing sera. The sensitivity was restored in most cases by recovering the RBC by centrifugation before testing. In a preliminary experiment, there was no significant difference in antibody-binding inhibition using fresh infected RBC and RBC dried on filter-paper and recovered by elution, although there was greater variation in the latter samples.

  15. Estimating Geographical Variation in the Risk of Zoonotic Plasmodium knowlesi Infection in Countries Eliminating Malaria

    PubMed Central

    Shearer, Freya M.; Huang, Zhi; Weiss, Daniel J.; Wiebe, Antoinette; Gibson, Harry S.; Battle, Katherine E.; Pigott, David M.; Brady, Oliver J.; Putaporntip, Chaturong; Jongwutiwes, Somchai; Lau, Yee Ling; Manske, Magnus; Amato, Roberto; Elyazar, Iqbal R. F.; Vythilingam, Indra; Bhatt, Samir; Gething, Peter W.; Singh, Balbir; Golding, Nick; Hay, Simon I.

    2016-01-01

    Background Infection by the simian malaria parasite, Plasmodium knowlesi, can lead to severe and fatal disease in humans, and is the most common cause of malaria in parts of Malaysia. Despite being a serious public health concern, the geographical distribution of P. knowlesi malaria risk is poorly understood because the parasite is often misidentified as one of the human malarias. Human cases have been confirmed in at least nine Southeast Asian countries, many of which are making progress towards eliminating the human malarias. Understanding the geographical distribution of P. knowlesi is important for identifying areas where malaria transmission will continue after the human malarias have been eliminated. Methodology/Principal Findings A total of 439 records of P. knowlesi infections in humans, macaque reservoir and vector species were collated. To predict spatial variation in disease risk, a model was fitted using records from countries where the infection data coverage is high. Predictions were then made throughout Southeast Asia, including regions where infection data are sparse. The resulting map predicts areas of high risk for P. knowlesi infection in a number of countries that are forecast to be malaria-free by 2025 (Malaysia, Cambodia, Thailand and Vietnam) as well as countries projected to be eliminating malaria (Myanmar, Laos, Indonesia and the Philippines). Conclusions/Significance We have produced the first map of P. knowlesi malaria risk, at a fine-scale resolution, to identify priority areas for surveillance based on regions with sparse data and high estimated risk. Our map provides an initial evidence base to better understand the spatial distribution of this disease and its potential wider contribution to malaria incidence. Considering malaria elimination goals, areas for prioritised surveillance are identified. PMID:27494405

  16. Use of polymerase chain reaction technique to confirm VecTest screening results in Plasmodium falciparum and Plasmodium vivax VK 210 laboratory-infected Anopheles stephensi mosquitoes.

    PubMed

    Santos-Ciminera, Patricia D; Acheé, Nicole L; Quinnan, Gerald V; Roberts, Donald R

    2004-09-01

    We evaluated polymerase chain reaction (PCR) to confirm immunoassays for malaria parasites in mosquito pools after a failure to detect malaria with PCR during an outbreak in which pools tested positive using VecTest and enzyme-linked immunosorbent assay (ELISA). We combined VecTest, ELISA, and PCR to detect Plasmodium falciparum and Plasmodium vivax VK 210. Each mosquito pool, prepared in triplicate, consisted of 1 exposed Anopheles stephensi and up to 9 unfed mosquitoes. The results of VecTest and ELISA were concordant. DNA from a subset of the pools, 1 representative of each ratio of infected to uninfected mosquitoes, was extracted and used as template in PCR. All P. vivax pools were PCR positive but some needed additional processing for removal of apparent inhibitors before positive results were obtained. One of the pools selected for P. falciparum was negative by PCR, probably because of losses or contamination during DNA extraction; 2 remaining pools at this ratio were PCR positive. Testing pools by VecTest, ELISA, and PCR is feasible, and PCR is useful for confirmation of immunoassays. An additional step might be needed to remove potential inhibitors from pools prior to PCR.

  17. Multiple genotypes of the merozoite surface proteins 1 and 2 in Plasmodium falciparum infections in a hypoendemic area in Iran.

    PubMed

    Zakeri, Sedigheh; Bereczky, Sándor; Naimi, Parin; Pedro Gil, J; Djadid, Navid Dinparast; Färnert, Anna; Snounou, Georges; Björkman, Anders

    2005-10-01

    In Iran, malaria transmission mainly occurs in south-eastern regions through both Plasmodium falciparum and P. vivax. The genetic diversity of P. falciparum isolates was analysed in 108 patients attending the regional hospital in Chabahar District, using the molecular markers msp1 and msp2. Multiple genotypes were detected in 87% of patients and the mean numbers of msp1 and msp2 genotypes were 2.51 (95% CI: 2.29-2.73) and 2.61 (95% CI: 2.39-2.83) respectively. Various allelic types of msp1 and msp2 were found, with msp2 3D7/IC type detected in 94% of infections. Plasmodium falciparum infections in south-east Iran appear to have a higher genetic diversity than expected for an area of low transmission. A situation of higher transmission in this area may be emerging, possibly because of reduced efficacy of first-line treatments.

  18. Morbidity and mortality associated with Plasmodium vivax and Plasmodium falciparum infection in a tertiary care kidney hospital.

    PubMed

    Imtiaz, Salman; Drohlia, Murtaza F; Nasir, Kiran; Hussain, Mehwish; Ahmad, Aasim

    2015-11-01

    Malaria is a disease of tropical regions and both types of plasmodia, i.e. Plasmodium falciparum and Plasmodium vivax, cause significant morbidity and mortality. P. vivax was thought to be benign and cause less morbidity and mortality. Many reports showed the devastating effect of vivax malaria too. We compared the clinical symptoms, laboratory markers, treatment and outcome of both the plasmodia. This is a retrospective analysis of 95 patients admitted to The Kidney Center, Karachi in a duration of 15 years (1997-2012); 45 patients with falciparum malaria and 50 patients with vivax malaria, and compared the clinical presentation, laboratory workup, treatment and outcome in both groups. The two groups constitute a mixed population of diabetes, chronic kidney disease (CKD) and hemodialysis patients. Both plasmodia have an equal clinical impact in terms of fever and rigors, anorexia, nausea, feeling of dyspnea, change in the mental status, changes in the urine color, diarrhea, volume depletion and pedal edema. However, patients with falciparum had significantly more vomiting (P = 0.02), oliguria (P = 0.003) and jaundice (P = 0.003). Laboratory parameters also showed a severe impact of falciparum, as there was more severe anemia and kidney and liver dysfunction. More patients were treated with dialysis and blood transfusion in the falciparum group. The outcome in the two groups was not significantly different in terms of death and days of hospitalization. Falciparum malaria has a higher clinical impact than the vivax malaria, but vivax is not as benign as it was once thought to be. It also has devastating effects on vulnerable populations like patients with CKD and diabetes.

  19. Frequency and distribution of mixed Plasmodium falciparum-vivax infections in French Guiana between 2000 and 2008.

    PubMed

    Ginouves, Marine; Veron, Vincent; Musset, Lise; Legrand, Eric; Stefani, Aurélia; Prevot, Ghislaine; Demar, Magalie; Djossou, Félix; Brousse, Paul; Nacher, Mathieu; Carme, Bernard

    2015-11-10

    The two main plasmodial species in French Guiana are Plasmodium vivax and Plasmodium falciparum whose respective prevalence influences the frequency of mixed plasmodial infections. The accuracy of their diagnosis is influenced by the sensitivity of the method used, whereas neither microscopy nor rapid diagnostic tests allow a satisfactory evaluation of mixed plasmodial infections. In the present study, the frequency of mixed infections in different part of French Guiana was determined using real time PCR, a sensitive and specific technique. From 400 cases of malaria initially diagnosed by microscopy, real time PCR showed that 10.75 % of the cases were mixed infections. Their prevalence varied considerably between geographical areas. The presence, in equivalent proportions, of the two plasmodial species in eastern French Guiana was associated with a much higher prevalence of mixed plasmodial infections than in western French Guiana, where the majority of the population was Duffy negative and thus resistant to vivax malaria. Clinicians must be more vigilant regarding mixed infections in co-endemic P. falciparum/P. vivax areas, in order to deliver optimal care for patients suffering from malaria. This may involve the use of rapid diagnostic tests capable of detecting mixed infections or low density single infections. This is important as French Guiana moves towards malaria elimination.

  20. Risk factors for Plasmodium vivax infection in the Lacandon forest, southern Mexico.

    PubMed

    Danis-Lozano, R; Rodriguez, M H; Gonzalez-Ceron, L; Hernandez-Avila, M

    1999-06-01

    A study was conducted to characterize the risk of Plasmodium vivax infection in the Lacandon forest, southern Mexico. Blood samples and questionnaire data were collected in 1992. Malaria cases (n = 137) were identified by the presence of symptoms and a positive thick blood smear. The control group included individuals with negative antibody titres and no history of malaria (n = 4994). From 7628 individuals studied, 1006 had anti-P. vivax antibodies. Seroprevalence increased with age. Risk factors associated with infection included: place of birth outside the village of residence (odds ratio, OR 11.67; 95% CI 5.21-26.11); no use of medical services (OR 4.69, 95% CI 3.01-7.29), never using bed-nets (OR 3.98, 95 % CI 1.23-12.86) and poor knowledge of malaria transmission, prevention and treatment (OR 2.30, 95 % CI 1.30-4.07). Health education represents the best recommendation for controlling the disease in the area.

  1. Type I Interferons Regulate Immune Responses in Humans with Blood-Stage Plasmodium falciparum Infection

    PubMed Central

    Montes de Oca, Marcela; Kumar, Rajiv; de Labastida Rivera, Fabian; Amante, Fiona H.; Sheel, Meru; Faleiro, Rebecca J.; Bunn, Patrick T.; Best, Shannon E.; Beattie, Lynette; Ng, Susanna S.; Edwards, Chelsea L.; Boyle, Glen M.; Price, Ric N.; Anstey, Nicholas M.; Loughland, Jessica R.; Burel, Julie; Doolan, Denise L.; Haque, Ashraful; McCarthy, James S.; Engwerda, Christian R.

    2016-01-01

    Summary The development of immunoregulatory networks is important to prevent disease. However, these same networks allow pathogens to persist and reduce vaccine efficacy. Here, we identify type I interferons (IFNs) as important regulators in developing anti-parasitic immunity in healthy volunteers infected for the first time with Plasmodium falciparum. Type I IFNs suppressed innate immune cell function and parasitic-specific CD4+ T cell IFNγ production, and they promoted the development of parasitic-specific IL-10-producing Th1 (Tr1) cells. Type I IFN-dependent, parasite-specific IL-10 production was also observed in P. falciparum malaria patients in the field following chemoprophylaxis. Parasite-induced IL-10 suppressed inflammatory cytokine production, and IL-10 levels after drug treatment were positively associated with parasite burdens before anti-parasitic drug administration. These findings have important implications for understanding the development of host immune responses following blood-stage P. falciparum infection, and they identify type I IFNs and related signaling pathways as potential targets for therapies or vaccine efficacy improvement. PMID:27705789

  2. The Plasmodium falciparum-Specific Human Memory B Cell Compartment Expands Gradually with Repeated Malaria Infections

    PubMed Central

    Weiss, Greta E.; Traore, Boubacar; Kayentao, Kassoum; Ongoiba, Aissata; Doumbo, Safiatou; Doumtabe, Didier; Kone, Younoussou; Dia, Seydou; Guindo, Agnes; Traore, Abdramane; Huang, Chiung-Yu; Miura, Kazutoyo; Mircetic, Marko; Li, Shanping; Baughman, Amy; Narum, David L.; Miller, Louis H.; Doumbo, Ogobara K.; Pierce, Susan K.; Crompton, Peter D.

    2010-01-01

    Immunity to Plasmodium falciparum (Pf) malaria is only acquired after years of repeated infections and wanes rapidly without ongoing parasite exposure. Antibodies are central to malaria immunity, yet little is known about the B-cell biology that underlies the inefficient acquisition of Pf-specific humoral immunity. This year-long prospective study in Mali of 185 individuals aged 2 to 25 years shows that Pf-specific memory B-cells and antibodies are acquired gradually in a stepwise fashion over years of repeated Pf exposure. Both Pf-specific memory B cells and antibody titers increased after acute malaria and then, after six months of decreased Pf exposure, contracted to a point slightly higher than pre-infection levels. This inefficient, stepwise expansion of both the Pf-specific memory B-cell and long-lived antibody compartments depends on Pf exposure rather than age, based on the comparator response to tetanus vaccination that was efficient and stable. These observations lend new insights into the cellular basis of the delayed acquisition of malaria immunity. PMID:20502681

  3. Host vascular endothelial growth factor is trophic for Plasmodium falciparum-infected red blood cells.

    PubMed

    Sachanonta, Navakanit; Medana, Isabelle M; Roberts, Rachel; Jones, Margaret; Day, Nicholas P J; White, Nicholas J; Ferguson, David J P; Turner, Gareth D H; Pongponratn, Emsri

    2008-03-01

    Plasmodium falciparum, the protozoan parasite responsible for severe malaria infection, undergoes a complex life cycle. Infected red blood cells (iRBC) sequester in host cerebral microvessels, which underlies the pathology of cerebral malaria. Using immunohistochemistry on post mortem brain samples, we demonstrated positive staining for vascular endothelial growth factor (VEGF) on iRBC. Confocal microscopy of cultured iRBC revealed accumulation of VEGF within the parasitophorous vacuole, expression of host VEGF-receptor 1 and activated VEGF-receptor 2 on the surface of iRBC, but no accumulation of VEGF receptors within the iRBC. Addition of VEGF to parasite cultures had a trophic effect on parasite growth and also partially rescued growth of drug treated parasites. Both these effects were abrogated when parasites were grown in serum-free medium, suggesting a requirement for soluble VEGF receptor. We conclude that P. falciparum iRBC can bind host VEGF-R on the erythrocyte membrane and accumulate host VEGF within the parasitophorous vacuole, which may have a trophic effect on parasite growth.

  4. Risk factors for Plasmodium vivax infection in the Lacandon forest, southern Mexico.

    PubMed Central

    Danis-Lozano, R.; Rodriguez, M. H.; Gonzalez-Ceron, L.; Hernandez-Avila, M.

    1999-01-01

    A study was conducted to characterize the risk of Plasmodium vivax infection in the Lacandon forest, southern Mexico. Blood samples and questionnaire data were collected in 1992. Malaria cases (n = 137) were identified by the presence of symptoms and a positive thick blood smear. The control group included individuals with negative antibody titres and no history of malaria (n = 4994). From 7628 individuals studied, 1006 had anti-P. vivax antibodies. Seroprevalence increased with age. Risk factors associated with infection included: place of birth outside the village of residence (odds ratio, OR 11.67; 95% CI 5.21-26.11); no use of medical services (OR 4.69, 95% CI 3.01-7.29), never using bed-nets (OR 3.98, 95 % CI 1.23-12.86) and poor knowledge of malaria transmission, prevention and treatment (OR 2.30, 95 % CI 1.30-4.07). Health education represents the best recommendation for controlling the disease in the area. PMID:10459651

  5. Distinct physiological states of Plasmodium falciparum in malaria-infected patients.

    PubMed

    Daily, J P; Scanfeld, D; Pochet, N; Le Roch, K; Plouffe, D; Kamal, M; Sarr, O; Mboup, S; Ndir, O; Wypij, D; Levasseur, K; Thomas, E; Tamayo, P; Dong, C; Zhou, Y; Lander, E S; Ndiaye, D; Wirth, D; Winzeler, E A; Mesirov, J P; Regev, A

    2007-12-13

    Infection with the malaria parasite Plasmodium falciparum leads to widely different clinical conditions in children, ranging from mild flu-like symptoms to coma and death. Despite the immense medical implications, the genetic and molecular basis of this diversity remains largely unknown. Studies of in vitro gene expression have found few transcriptional differences between different parasite strains. Here we present a large study of in vivo expression profiles of parasites derived directly from blood samples from infected patients. The in vivo expression profiles define three distinct transcriptional states. The biological basis of these states can be interpreted by comparison with an extensive compendium of expression data in the yeast Saccharomyces cerevisiae. The three states in vivo closely resemble, first, active growth based on glycolytic metabolism, second, a starvation response accompanied by metabolism of alternative carbon sources, and third, an environmental stress response. The glycolytic state is highly similar to the known profile of the ring stage in vitro, but the other states have not been observed in vitro. The results reveal a previously unknown physiological diversity in the in vivo biology of the malaria parasite, in particular evidence for a functional mitochondrion in the asexual-stage parasite, and indicate in vivo and in vitro studies to determine how this variation may affect disease manifestations and treatment.

  6. Usefulness of the recombinant liver stage antigen-3 for an early serodiagnosis of Plasmodium falciparum infection

    PubMed Central

    Lee, Hyeong-Woo; Moon, Sung-Ung; Ryu, Hye-Sun; Kim, Yeon-Joo; Cho, Shin-Hyeong; Chung, Gyung-Tae; Lin, Khin; Na, Byoung-Kuk; Kong, Yoon; Chung, Kyung-Suk

    2006-01-01

    In order to develop tools for an early serodiagnosis of Plasmodium falciparum infection, we evaluated the usefulness of P. falciparum liver stage antigen-3 (LSA-3) as a serodiagnostic antigen. A portion of LSA-3 gene was cloned, and its recombinant protein (rLSA-3) was expressed in Escherichia coli and purified by column chromatography. The purified rLSA-3 and 120 test blood/serum samples collected from inhabitants in malaria-endemic areas of Mandalay, Myanmar were used for this study. In microscopic examinations of blood samples, P. falciparum positive rate was 39.1% (47/120) in thin smear trials, and 33.3% (40/120) in thick smear trials. Although the positive rate associated with the rLSA-3 (30.8%) was lower than that of the blood stage antigens (70.8%), rLSA-3 based enzyme-linked immunosorbent assay could detect 12 seropositive cases (10.0%), in which blood stage antigens were not detected. These results indicate that the LSA-3 is a useful antigen for an early serodiagnosis of P. falciparum infection. PMID:16514282

  7. Usefulness of the recombinant liver stage antigen-3 for an early serodiagnosis of Plasmodium falciparum infection.

    PubMed

    Lee, Hyeong-Woo; Moon, Sung-Ung; Ryu, Hye-Sun; Kim, Yeon-Joo; Cho, Shin-Hyeong; Chung, Gyung-Tae; Lin, Khin; Na, Byoung-Kuk; Kong, Yoon; Chung, Kyung-Suk; Kim, Tong-Soo

    2006-03-01

    In order to develop tools for an early serodiagnosis of Plasmodium falciparum infection, we evaluated the usefulness of P. falciparum liver stage antigen-3 (LSA-3) as a serodiagnostic antigen. A portion of LSA-3 gene was cloned, and its recombinant protein (rLSA-3) was expressed in Escherichia coli and purified by column chromatography. The purified rLSA-3 and 120 test blood/serum samples collected from inhabitants in malaria-endemic areas of Mandalay, Myanmar were used for this study. In microscopic examinations of blood samples, P. falciparum positive rate was 39.1% (47/120) in thin smear trials, and 33.3% (40/120) in thick smear trials. Although the positive rate associated with the rLSA-3 (30.8%) was lower than that of the blood stage antigens (70.8%), rLSA-3 based enzyme-linked immunosorbent assay could detect 12 seropositive cases (10.0%), in which blood stage antigens were not detected. These results indicate that the LSA-3 is a useful antigen for an early serodiagnosis of P. falciparum infection.

  8. A nitrocellulose membrane-based ELISA for the detection of Plasmodium infections in mosquitos.

    PubMed Central

    Petros, B. L.; Procell, P. M.; Campbell, G. H.; Collins, F. H.

    1989-01-01

    A nitrocellulose (NC) membrane was evaluated as a solid-phase support for the detection of malaria-infected mosquitos using monoclonal antibodies (MAb) with a laboratory model based on Plasmodium inui and Anopheles dirus. MAbs produced against sporozoites of the N34 strain of P. inui, and selected by immunofluorescence assay and the circumsporozoite precipitin test, were used. A one-site indirect NC-ELISA that used unlabelled MAb and enzyme-labelled anti-mouse IgG was developed. Its sensitivity was about 200 sporozoites and it reliably detected one infected mosquito in a pool of 20. This indirect NC-ELISA has the advantage that it does not require direct conjugation of the MAb to an enzyme or biotin. In the direct one-site NC-ELISA, which is also reported, the relatively simple biotinylation procedure was an alternative to the enzyme- or radiolabelled MAbs. The NC-ELISAs were simple and rapid. Furthermore, the indirect NC-ELISA can be used to detect sporozoite antigen localized in various body sectors of mosquitos. Images Fig. 1 Fig. 2a Fig. 3 Fig. 4 Fig. 5 PMID:2575463

  9. Plasmodium vivax and Mansonella ozzardi co-infection in north-western Argentina

    PubMed Central

    2013-01-01

    A case of co-infection with Plasmodium vivax and Mansonella ozzardi was detected in a blood sample from a person who had shown symptoms of malaria and lived in a city that was close to the Argentina/Bolivia border. The case was detected during a random revision of thick and thin smears from patients diagnosed with malaria from various towns and cities located in north-western Argentina between 1983 and 2001. Trophozoites of P. vivax were observed in the thin blood smear along with M. ozzardi microfilaria (larval form), which presented a long, slender, pointed anucleate tail and the absence of the sheath. This last characteristic is shared with Mansonella perstans, Mansonella streptocerca and Onchocerca volvulus. More rigorously controlled studies to detect other co-infection cases in the area as well as the possibility of importation from Bolivia into Argentina are currently ongoing. The relationship between the malaria parasite and microfilaria, the potential effect of malaria treatment on the development of M. ozzardi, and the possible impact of this microfilaria on the immunity of a person against P. vivax are all still unknown. This contribution constitutes a point of focus for future studies involving the interaction between the parasites and the potential risk that humans are exposed to. PMID:23866313

  10. Diversity, host switching and evolution of Plasmodium vivax infecting African great apes.

    PubMed

    Prugnolle, Franck; Rougeron, Virginie; Becquart, Pierre; Berry, Antoine; Makanga, Boris; Rahola, Nil; Arnathau, Céline; Ngoubangoye, Barthélémy; Menard, Sandie; Willaume, Eric; Ayala, Francisco J; Fontenille, Didier; Ollomo, Benjamin; Durand, Patrick; Paupy, Christophe; Renaud, François

    2013-05-14

    Plasmodium vivax is considered to be absent from Central and West Africa because of the protective effect of Duffy negativity. However, there are reports of persons returning from these areas infected with this parasite and observations suggesting the existence of transmission. Among the possible explanations for this apparent paradox, the existence of a zoonotic reservoir has been proposed. May great apes be this reservoir? We analyze the mitochondrial and nuclear genetic diversity of P. vivax parasites isolated from great apes in Africa and compare it to parasites isolated from travelers returning from these regions of Africa, as well as to human isolates distributed all over the world. We show that the P. vivax sequences from parasites of great apes form a clade genetically distinct from the parasites circulating in humans. We show that this clade's parasites can be infectious to humans by describing the case of a traveler returning from the Central African Republic infected with one of them. The relationship between this P. vivax clade in great apes and the human isolates is discussed.

  11. Plasmodium vivax and Mansonella ozzardi co-infection in north-western Argentina.

    PubMed

    Dantur Juri, María J; Veggiani Aybar, Cecilia A; Ortega, Eugenia S; Galante, Guillermina B; Zaidenberg, Mario O

    2013-07-17

    A case of co-infection with Plasmodium vivax and Mansonella ozzardi was detected in a blood sample from a person who had shown symptoms of malaria and lived in a city that was close to the Argentina/Bolivia border. The case was detected during a random revision of thick and thin smears from patients diagnosed with malaria from various towns and cities located in north-western Argentina between 1983 and 2001. Trophozoites of P. vivax were observed in the thin blood smear along with M. ozzardi microfilaria (larval form), which presented a long, slender, pointed anucleate tail and the absence of the sheath. This last characteristic is shared with Mansonella perstans, Mansonella streptocerca and Onchocerca volvulus. More rigorously controlled studies to detect other co-infection cases in the area as well as the possibility of importation from Bolivia into Argentina are currently ongoing. The relationship between the malaria parasite and microfilaria, the potential effect of malaria treatment on the development of M. ozzardi, and the possible impact of this microfilaria on the immunity of a person against P. vivax are all still unknown. This contribution constitutes a point of focus for future studies involving the interaction between the parasites and the potential risk that humans are exposed to.

  12. Placental Malaria in Colombia: Histopathologic Findings in Plasmodium vivax and P. falciparum Infections

    PubMed Central

    Carmona-Fonseca, Jaime; Arango, Eliana; Maestre, Amanda

    2013-01-01

    Studies on gestational malaria and placental malaria have been scarce in malaria-endemic areas of the Western Hemisphere. To describe the histopathology of placental malaria in Colombia, a longitudinal descriptive study was conducted. In this study, 179 placentas were studied by histologic analysis (112 with gestational malaria and 67 negative for malaria). Placental malaria was confirmed in 22.35%, 50.0% had previous infections, and 47.5% had acute infections. Typical malaria-associated changes were observed in 37%. The most common changes were villitis, intervillitis, deciduitis, increased fibrin deposition, increased syncytial knots, mononuclear (monocytes/macrophages and lymphocytes), polymorphonuclear cell infiltration, and trophozoites in fetal erythrocytes. No association was found between type of placental changes observed and histopathologic classification of placental malaria. The findings are consistent with those reported for placental malaria in other regions. Plasmodium vivax was the main parasite responsible for placental and gestational malaria, but its role in the pathogenesis of placental malaria was not conclusive. PMID:23546807

  13. Plasmodium relictum infection and MHC diversity in the house sparrow (Passer domesticus).

    PubMed

    Loiseau, Claire; Zoorob, Rima; Robert, Alexandre; Chastel, Olivier; Julliard, Romain; Sorci, Gabriele

    2011-04-22

    Antagonistic coevolution between hosts and parasites has been proposed as a mechanism maintaining genetic diversity in both host and parasite populations. In particular, the high level of genetic diversity usually observed at the major histocompatibility complex (MHC) is generally thought to be maintained by parasite-driven selection. Among the possible ways through which parasites can maintain MHC diversity, diversifying selection has received relatively less attention. This hypothesis is based on the idea that parasites exert spatially variable selection pressures because of heterogeneity in parasite genetic structure, abundance or virulence. Variable selection pressures should select for different host allelic lineages resulting in population-specific associations between MHC alleles and risk of infection. In this study, we took advantage of a large survey of avian malaria in 13 populations of the house sparrow (Passer domesticus) to test this hypothesis. We found that (i) several MHC alleles were either associated with increased or decreased risk to be infected with Plasmodium relictum, (ii) the effects were population specific, and (iii) some alleles had antagonistic effects across populations. Overall, these results support the hypothesis that diversifying selection in space can maintain MHC variation and suggest a pattern of local adaptation where MHC alleles are selected at the local host population level.

  14. VALIDATION OF MICROSATELLITE MARKERS FOR USE IN GENOTYPING POLYCLONAL PLASMODIUM FALCIPARUM INFECTIONS

    PubMed Central

    GREENHOUSE, BRYAN; MYRICK, ALISSA; DOKOMAJILAR, CHRISTIAN; WOO, JONATHAN M.; CARLSON, ELAINE J.; ROSENTHAL, PHILIP J.; DORSEY, GRANT

    2006-01-01

    Genotyping methods for Plasmodium falciparum drug efficacy trials have not been standardized and may fail to accurately distinguish recrudescence from new infection, especially in high transmission areas where polyclonal infections are common. We developed a simple method for genotyping using previously identified microsatellites and capillary electrophoresis, validated this method using mixtures of laboratory clones, and applied the method to field samples. Two microsatellite markers produced accurate results for single-clone but not polyclonal samples. Four other microsatellite markers were as sensitive as, and more specific than, commonly used genotyping techniques based on merozoite surface proteins 1 and 2. When applied to samples from 15 patients in Burkina Faso with recurrent parasitemia after treatment with sulphadoxine-pyrimethamine, the addition of these four microsatellite markers to msp1 and msp2 genotyping resulted in a reclassification of outcomes that strengthened the association between dhfr 59R, an anti-folate resistance mutation, and recrudescence (P = 0.31 versus P = 0.03). Four microsatellite markers performed well on polyclonal samples and may provide a valuable addition to genotyping for clinical drug efficacy studies in high transmission areas. PMID:17123974

  15. Preferentially expanding Vγ1(+) γδ T cells are associated with protective immunity against Plasmodium infection in mice.

    PubMed

    Inoue, Shin-Ichi; Niikura, Mamoru; Asahi, Hiroko; Iwakura, Yoichiro; Kawakami, Yasushi; Kobayashi, Fumie

    2017-04-01

    γδ T cells play a crucial role in controlling malaria parasites. Dendritic cell (DC) activation via CD40 ligand (CD40L)-CD40 signaling by γδ T cells induces protective immunity against the blood-stage Plasmodium berghei XAT (PbXAT) parasites in mice. However, it is unknown which γδ T-cell subset has an effector role and is required to control the Plasmodium infection. Here, using antibodies to deplete TCR Vγ1(+) cells, we saw that Vγ1(+) γδ T cells were important for the control of PbXAT infection. Splenic Vγ1(+) γδ T cells preferentially expand and express CD40L, and both Vγ1(+) and Vγ4(+) γδ T cells produce IFN-γ during infection. Although expression of CD40L on Vγ1(+) γδ T cells is maintained during infection, the IFN-γ positivity of Vγ1(+) γδ T cells is reduced in late-phase infection due to γδ T-cell dysfunction. In Plasmodium-infected IFN-γ signaling-deficient mice, DC activation is reduced, resulting in the suppression of γδ T-cell dysfunction and the dampening of γδ T-cell expansion in the late phase of infection. Our data suggest that Vγ1(+) γδ T cells represent a major subset responding to PbXAT infection and that the Vγ1(+) γδ T-cell response is dependent on IFN-γ-activated DCs.

  16. Sustained Activation of Akt Elicits Mitochondrial Dysfunction to Block Plasmodium falciparum Infection in the Mosquito Host

    PubMed Central

    Drexler, Anna L.; Antonova-Koch, Yevgeniya; Sakaguchi, Danielle; Napoli, Eleonora; Wong, Sarah; Price, Mark S.; Eigenheer, Richard; Phinney, Brett S.; Pakpour, Nazzy; Pietri, Jose E.; Cheung, Kong; Georgis, Martha; Riehle, Michael

    2013-01-01

    The overexpression of activated, myristoylated Akt in the midgut of female transgenic Anopheles stephensi results in resistance to infection with the human malaria parasite Plasmodium falciparum but also decreased lifespan. In the present study, the understanding of mitochondria-dependent midgut homeostasis has been expanded to explain this apparent paradox in an insect of major medical importance. Given that Akt signaling is essential for cell growth and survival, we hypothesized that sustained Akt activation in the mosquito midgut would alter the balance of critical pathways that control mitochondrial dynamics to enhance parasite killing at some cost to survivorship. Toxic reactive oxygen and nitrogen species (RNOS) rise to high levels in the midgut after blood feeding, due to a combination of high NO production and a decline in FOXO-dependent antioxidants. Despite an apparent increase in mitochondrial biogenesis in young females (3 d), energy deficiencies were apparent as decreased oxidative phosphorylation and increased [AMP]/[ATP] ratios. In addition, mitochondrial mass was lower and accompanied by the presence of stalled autophagosomes in the posterior midgut, a critical site for blood digestion and stem cell-mediated epithelial maintenance and repair, and by functional degradation of the epithelial barrier. By 18 d, the age at which An. stephensi would transmit P. falciparum to human hosts, mitochondrial dysfunction coupled to Akt-mediated repression of autophagy/mitophagy was more evident and midgut epithelial structure was markedly compromised. Inhibition of RNOS by co-feeding of the nitric-oxide synthase inhibitor L-NAME at infection abrogated Akt-dependent killing of P. falciparum that begins within 18 h of infection in 3–5 d old mosquitoes. Hence, Akt-induced changes in mitochondrial dynamics perturb midgut homeostasis to enhance parasite resistance and decrease mosquito infective lifespan. Further, quality control of mitochondrial function in the

  17. Maturation of Plasmodium falciparum in multiply infected erythrocytes and the potential role in malaria pathogenesis.

    PubMed

    Orjih, Augustine U

    2014-11-01

    Erythrocytes containing two or more parasites, referred to here as multiply infected erythrocytes (MIEs), are common in the blood of humans infected by Plasmodium falciparum. It is necessary to study these cells closely because the excess numbers of parasites they contain suggest that they could be overloaded with virulence factors. Here, microscopic examinations of blood smears from patients showed that up to seven merozoites can successfully invade an erythrocyte and mature to ring stage. However, in vitro culture showed that only up to three parasites can mature to late schizont stage. These observations were made by culturing the parasites in erythrocytes containing hemoglobin AA (HbAA), HbAS, and HbSS. Biochemical analysis of saponin-concentrated culture suggests that more hemozoin is produced in a MIE than in a singly infected erythrocyte (SIE). Studies have shown that ingestion of excessive hemozoin destroys monocytes and neutrophils, which could impair the immune system. Cultured parasites were also examined by transmission electron microscopy, and it was found that the quantity of knobs was dramatically increased on the membranes of erythrocytes containing multiple schizonts, compared to those containing only one schizont. Knobs contain, among other things, P. falciparum erythrocyte membrane protein 1 (PfEMP1) complex which mediates sequestration and promotes severe malaria. These findings suggest that P. falciparum increases its virulence by producing MIEs. On sexual life cycle of the parasite, microphotographs are presented in this report showing, for the first time, that two gametocytes can develop in one erythrocyte; they are referred to here as twin gametocytes. It is not known whether they can infect mosquitoes.

  18. FRET imaging of hemoglobin concentration in Plasmodium falciparum-infected red cells.

    PubMed

    Esposito, Alessandro; Tiffert, Teresa; Mauritz, Jakob M A; Schlachter, Simon; Bannister, Lawrence H; Kaminski, Clemens F; Lew, Virgilio L

    2008-01-01

    During its intraerythrocytic asexual reproduction cycle Plasmodium falciparum consumes up to 80% of the host cell hemoglobin, in large excess over its metabolic needs. A model of the homeostasis of falciparum-infected red blood cells suggested an explanation based on the need to reduce the colloid-osmotic pressure within the host cell to prevent its premature lysis. Critical for this hypothesis was that the hemoglobin concentration within the host cell be progressively reduced from the trophozoite stage onwards. The experiments reported here were designed to test this hypothesis by direct measurements of the hemoglobin concentration in live, infected red cells. We developed a novel, non-invasive method to quantify the hemoglobin concentration in single cells, based on Förster resonance energy transfer between hemoglobin molecules and the fluorophore calcein. Fluorescence lifetime imaging allowed the quantitative mapping of the hemoglobin concentration within the cells. The average fluorescence lifetimes of uninfected cohorts was 270+/-30 ps (mean+/-SD; N = 45). In the cytoplasm of infected cells the fluorescence lifetime of calcein ranged from 290+/-20 ps for cells with ring stage parasites to 590+/-13 ps and 1050+/-60 ps for cells with young trophozoites and late stage trophozoite/early schizonts, respectively. This was equivalent to reductions in hemoglobin concentration spanning the range from 7.3 to 2.3 mM, in line with the model predictions. An unexpected ancillary finding was the existence of a microdomain under the host cell membrane with reduced calcein quenching by hemoglobin in cells with mature trophozoite stage parasites. The results support the predictions of the colloid-osmotic hypothesis and provide a better understanding of the homeostasis of malaria-infected red cells. In addition, they revealed the existence of a distinct peripheral microdomain in the host cell with limited access to hemoglobin molecules indicating the concentration of

  19. Lymphocyte migration in murine malaria during the primary patent parasitaemia of Plasmodium chabaudi infections.

    PubMed Central

    Kumararatne, D S; Phillips, R S; Sinclair, D; Parrott, M V; Forrester, J B

    1987-01-01

    Inoculation of adult C57/BC mice with 10(6) red cells infected with Plasmodium chabaudi induces an acute primary parasitaemia peaking around the 8th or 9th day and lasting 10-14 days. Concomitantly, the spleen enlarges to reach 6-7 times its normal weight by the 11th day. The major component of this increase is between day 9 and 11, due primarily to an increase in erythropoietic cells in the red pulp. Although initially the white pulp increases in size, by day 11 it shows partial lymphocyte depletion which coincides with the occurrence of massive absolute lymphocytosis in the peripheral blood. 3H-Thymidine labelling in vivo suggests that this lymphocytosis is not due to lymphocytopoiesis. Collectively, these findings suggest a redistribution of lymphocytes. Lymphocyte migration was investigated around peak parasitaemia, using enriched populations of T and B cells labelled with 51Cr. The traffic patterns of these cells were followed over 36 h. These studies show decreased uptake (or decreased retention) of T and B cells by spleens of infected mice. Concomitantly, there is increased retention of T and B cells in the liver and lungs of infected mice, suggesting a complex redistribution of these cells. Lymphocyte migration to lymph nodes was unimpaired in these animals. Similar changes in T and B cell migration do not occur in Babesia microti infections in C57/BL mice. We relate our findings to histological and histochemical changes in the liver and spleen of malarious mice and discuss the significance of these findings to immunosuppression in malaria and to the development of parasiticidal immunity. Images Fig. 3a Fig. 3b Fig. 3c Fig. 3d Fig. 3 PMID:3498567

  20. Malaria in pregnancy in rural Mozambique: the role of parity, submicroscopic and multiple Plasmodium falciparum infections.

    PubMed

    Saute, Francisco; Menendez, Clara; Mayor, Alfredo; Aponte, John; Gomez-Olive, Xavier; Dgedge, Martinho; Alonso, Pedro

    2002-01-01

    Falciparum malaria affects pregnant women, especially primigravidae, but before malaria control programmes targeted to them can be designed, a description of the frequency and parity pattern of the infection is needed. There is little information on the frequency and effect of submicroscopic malaria infection, as well as on multiplicity of Plasmodium falciparum genotypes in pregnancy. This study aimed to describe the prevalence of malaria parasitaemia and anaemia and their relation to parity and age in pregnant women, during two malaria transmission seasons in a rural area of southern Mozambique. It also tried to assess the frequency and effect on anaemia of submicroscopic and multiple falciparum infections. A total of 686 pregnant women were enrolled in three cross-sectional community-based surveys during different transmission seasons in rural southern Mozambique. In each survey a questionnaire was administered on previous parity history, the gestational age was assessed, the axillary temperature recorded and both haematocrit and malaria parasitaemia were determined. We used polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis to determine submicroscopic and multiple P. falciparum infections in a subsample of women. A total of 156 women (23%) had microscopic parasitaemia, of which 144 (92%) were asexual forms of P. falciparum. The prevalence of clinical malaria was 18 of 534 (3%), that of anaemia, 382 of 649 (59%). In a multivariate analysis age but not parity was associated with an increased risk of microscopic parasitaemia. Anaemia was associated with microscopic P. falciparum parasitaemia. Both malaria parasitaemia and anaemia were more frequent during the rainy season. Although not statistically significant, submicroscopic infections tended to be more frequent among grand-multiparous pregnant women. Subpatent infections were not associated with increased anaemia. Multiplicity of infection was not associated with either

  1. TLR4 and TLR9 signals stimulate protective immunity against blood-stage Plasmodium yoelii infection in mice.

    PubMed

    Zhang, Yanjun; Zhu, Xiaotong; Feng, Yonghui; Pang, Wei; Qi, Zanmei; Cui, Liwang; Cao, Yaming

    2016-11-01

    The mechanisms regulating the induction of protective immunity against blood-stage malaria remain unclear. Resistant DBA/2 mouse develops a higher Th1 response compared with a susceptible BALB/c strain during Plasmodium yoelii (Py) infection. It is known that the T helper cell response is initiated and polarized by dendritic cells (DCs) of the innate immune system, during which TLR4 and TLR9 are important receptors for the innate recognition of the malaria parasite and its products. We hypothesized that TLR4/9 may play critical roles in the induction of protective immunity against Py infection. We used TLR4/9 antagonists and agonists to study their effects on mouse resistance to Py infection. We found that the administration of an antagonist prior to infection aggravated disease outcomes, impaired DC functions and suppressed the pro-inflammatory response to Py infection in resistant DBA/2 mice. Treatment with the TLR4 agonist lipopolysaccharide (LPS) but not TLR9 agonist significantly improved the survival rate of susceptible Py-infected BALB/c mice. LPS administration promoted the activation and expansion of DCs and drove a Th1-biased response. Our data demonstrate the important roles of TLR4/9 signals in inducing resistance to malaria parasites and provide evidence for the rational use of TLR agonists to potentiate protective immunity against Plasmodium infection. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. A restriction site to differentiate Plasmodium and Haemoproteus infections in birds: on the inefficiency of general primers for detection of mixed infections.

    PubMed

    Martínez, J; Martínez-DE LA Puente, J; Herrero, J; Del Cerro, S; Lobato, E; Rivero-DE Aguilar, J; Vásquez, R A; Merino, S

    2009-06-01

    Avian Plasmodium and Haemoproteus parasites are easily detected by DNA analyses of infected samples but only correctly assigned to each genus by sequencing and use of a phylogenetic approach. Here, we present a restriction site to differentiate between both parasite genera avoiding the use of those analyses. Alignments of 820 sequences currently listed in GenBank encoding a particular cytochrome B region of avian Plasmodium and Haemoproteus show a shared restriction site for both genera using the endonuclease Hpy CH4III. An additional restriction site is present in Plasmodium sequences that would initially allow differentiation of both genera by differential migration of digested products on gels. Overall 9 out of 326 sequences containing both potential restriction sites do not fit to the general rule. We used this differentiation of parasite genera based on Hpy CH4III restriction sites to evaluate the efficacy of 2 sets of general primers in detecting mixed infections. To do so, we used samples from hosts infected by parasites of both genera. The use of general primers was only able to detect 25% or less of the mixed infections. Therefore, parasite DNA amplification using general primers to determine the species composition of haemosporidian infections in individual hosts is not recommended. Specific primers for each species and study area should be designed until a new method can efficiently discriminate both parasites.

  3. Interaction between rifampicin, amodiaquine and artemether in mice infected with chloroquine resistant Plasmodium berghei

    PubMed Central

    2014-01-01

    Background Artemisinin-based combination therapy (ACT) remains the most effective chemotherapeutic strategy in the management of malaria. However, reports of reduced susceptibility of Plasmodium falciparum to the ACT justify the need for continued search for alternative anti-malarial drugs. The use of antibiotics with anti-malarial properties represents a potentially valuable chemotherapeutic option for the management of drug resistant infections. Thus, the intrinsic anti-malarial activity of the combination of clinical doses of rifampicin with amodiaquine and artemether was evaluated in an animal model using Plasmodium berghei. Methods A modification of the suppressive tests in vivo was employed. The anti-malarial activity of standard doses of amodiaquine (AQ) with or without artemether (ART) and combined with varying doses of rifampicin (RIF 15 mg/kg or RIF 30 mg/kg body weight) was evaluated in 40 mice sub-divided into eight groups and inoculated intraperitoneally with 1 × 107 red blood cells infected with chloroquine-resistant P. berghei ANKA strain. There were two control groups of animals, one group received amodiaquine alone while the other group received saline. Parasiticidal activity and survival of the animals were assessed over 21 days. Results Parasitaemia in the control animals peaked at 38% on day 9 and all animals died by day 10. The combination of amodiaquine with rifampicin 15 mg/kg body weight was the most effective of all the combinations and more efficacious than amodiaquine alone. The order of superiority of anti-malarial efficacy of the combinations was as follows; AQ + RIF 15 > AQ > AQ + ART + RIF 30 > AQ + ART + RIF 15 > AQ + RIF 30. Conclusion The combination of the clinical dose of rifampicin (15 mg/kg) with amodiaquine represents a potentially valuable treatment option in management of drug resistant malaria. In addition, the role of pharmacokinetic interaction in multiple drug therapy

  4. Non-falciparum malaria in Dakar: a confirmed case of Plasmodium ovale wallikeri infection.

    PubMed

    Diallo, Mamadou A; Badiane, Aida S; Diongue, Khadim; Deme, Awa; Lucchi, Naomi W; Gaye, Marie; Ndiaye, Tolla; Ndiaye, Mouhamadou; Sene, Louise K; Diop, Abdoulaye; Gaye, Amy; Ndiaye, Yaye D; Samb, Diama; Yade, Mamadou S; Ndir, Omar; Udhayakumar, Venkatachalam; Ndiaye, Daouda

    2016-08-24

    Plasmodium ovale is rarely described in Senegal. A case of clinical malaria due to P. ovale wallikeri in West Central of Senegal is reported. A 34-year-old male baker in Dakar, with no significant previous medical history, was admitted to a health clinic with fever and vomiting. Fever had been lasting for 4 days with peaks every 48 h. As monospecific Plasmodium falciparum HRP-2 RDT was negative, he was treated with antibiotics. However, owing to persisting symptoms, he was referred to the emergency unit of the Youssou Mbargane Diop Hospital, Dakar, Senegal. Clinical examination found impaired general condition. All other physical examinations were normal. Laboratory tests showed anaemia (haemoglobin 11.4 g/dl), severe thrombocytopaenia (platelets 30 × 10(9)/mm(3)), leukopenia (3650/mm(3)), lymphocytopenia (650/mm(3)). Renal function was normal as indicated by creatininaemia and uraemia (11 mg/l and 0.25 g/l, respectively) and liver enzymes were slightly elevated (aspartate aminotransferase 77 UI/l and alanine aminotransferase 82 UI/l). Blood smear evaluations in Parasitology Laboratory of Aristide Le Dantec Hospital showed malaria parasites of the species P. ovale with a 0.08 % parasitaemia. Molecular confirmation was done by real time PCR targeting the 18S rRNA gene. The P. ovale infection was further analysed to species level targeting the potra gene and was identified as P. ovale wallikeri. According to the hospital's malaria treatment guidelines for severe malaria, treatment consisted of intravenous quinine at hour 0 (start of treatment) and 24 h after initial treatment, followed by artemether-lumefantrine 24 h later. A negative microscopy was noted on day 3 post-treatment and the patient reported no further symptoms. Malaria due to non-falciparum species is probably underestimated in Senegal. RDTs specific to non-falciparum species and/or pan specific RDTs should be included as tools of diagnosis to fight against malaria in Senegal. In addition

  5. De Novo Generated Human Red Blood Cells in Humanized Mice Support Plasmodium falciparum Infection.

    PubMed

    Amaladoss, Anburaj; Chen, Qingfeng; Liu, Min; Dummler, Sara K; Dao, Ming; Suresh, Subra; Chen, Jianzhu; Preiser, Peter R

    2015-01-01

    Immunodeficient mouse-human chimeras provide a powerful approach to study host specific pathogens like Plasmodium (P.) falciparum that causes human malaria. Existing mouse models of P. falciparum infection require repeated injections of human red blood cells (RBCs). In addition, clodronate lipsomes and anti-neutrophil antibodies are injected to suppress the clearance of human RBCs by the residual immune system of the immunodeficient mice. Engraftment of NOD-scid Il2rg-/- mice with human hematopoietic stem cells leads to reconstitution of human immune cells. Although human B cell reconstitution is robust and T cell reconstitution is reasonable in the recipient mice, human RBC reconstitution is generally poor or undetectable. The poor reconstitution is mainly the result of a deficiency of appropriate human cytokines that are necessary for the development and maintenance of these cell lineages. Delivery of plasmid DNA encoding human erythropoietin and interleukin-3 into humanized mice by hydrodynamic tail-vein injection resulted in significantly enhanced reconstitution of erythrocytes. With this improved humanized mouse, here we show that P. falciparum infects de novo generated human RBCs, develops into schizonts and causes successive reinvasion. We also show that different parasite strains exhibit variation in their ability to infect these humanized mice. Parasites could be detected by nested PCR in the blood samples of humanized mice infected with P. falciparum K1 and HB3 strains for 3 cycles, whereas in other strains such as 3D7, DD2, 7G8, FCR3 and W2mef parasites could only be detected for 1 cycle. In vivo adaptation of K1 strain further improves the infection efficiency and parasites can be detected by microscopy for 3 cycles. The parasitemia ranges between 0.13 and 0.25% at the first cycle of infection, falls between 0.08 and 0.15% at the second cycle, and drops to barely detectable levels at the third cycle of infection. Compared to existing mouse models, our

  6. IFNγ and IL-12 Restrict Th2 Responses during Helminth/Plasmodium Co-Infection and Promote IFNγ from Th2 Cells

    PubMed Central

    Coomes, Stephanie M.; Pelly, Victoria S.; Kannan, Yashaswini; Okoye, Isobel S.; Czieso, Stephanie; Entwistle, Lewis J.; Perez-Lloret, Jimena; Nikolov, Nikolay; Potocnik, Alexandre J.; Biró, Judit; Langhorne, Jean; Wilson, Mark S.

    2015-01-01

    Parasitic helminths establish chronic infections in mammalian hosts. Helminth/Plasmodium co-infections occur frequently in endemic areas. However, it is unclear whether Plasmodium infections compromise anti-helminth immunity, contributing to the chronicity of infection. Immunity to Plasmodium or helminths requires divergent CD4+ T cell-driven responses, dominated by IFNγ or IL-4, respectively. Recent literature has indicated that Th cells, including Th2 cells, have phenotypic plasticity with the ability to produce non-lineage associated cytokines. Whether such plasticity occurs during co-infection is unclear. In this study, we observed reduced anti-helminth Th2 cell responses and compromised anti-helminth immunity during Heligmosomoides polygyrus and Plasmodium chabaudi co-infection. Using newly established triple cytokine reporter mice (Il4gfpIfngyfpIl17aFP635), we demonstrated that Il4gfp+ Th2 cells purified from in vitro cultures or isolated ex vivo from helminth-infected mice up-regulated IFNγ following adoptive transfer into Rag1–/– mice infected with P. chabaudi. Functionally, Th2 cells that up-regulated IFNγ were transcriptionally re-wired and protected recipient mice from high parasitemia. Mechanistically, TCR stimulation and responsiveness to IL-12 and IFNγ, but not type I IFN, was required for optimal IFNγ production by Th2 cells. Finally, blockade of IL-12 and IFNγ during co-infection partially preserved anti-helminth Th2 responses. In summary, this study demonstrates that Th2 cells retain substantial plasticity with the ability to produce IFNγ during Plasmodium infection. Consequently, co-infection with Plasmodium spp. may contribute to the chronicity of helminth infection by reducing anti-helminth Th2 cells and converting them into IFNγ-secreting cells. PMID:26147567

  7. Sporozoite Route of Infection Influences In Vitro var Gene Transcription of Plasmodium falciparum Parasites From Controlled Human Infections

    PubMed Central

    Dimonte, Sandra; Bruske, Ellen I.; Hass, Johanna; Supan, Christian; Salazar, Carmen L.; Held, Jana; Tschan, Serena; Esen, Meral; Flötenmeyer, Matthias; Koch, Iris; Berger, Jürgen; Bachmann, Anna; Sim, Betty K. L.; Hoffman, Stephen L.; Kremsner, Peter G.; Mordmüller, Benjamin; Frank, Matthias

    2016-01-01

    Background. Antigenic variation in Plasmodium falciparum is mediated by the multicopy var gene family. Each parasite possesses about 60 var genes, and switching between active var loci results in antigenic variation. In the current study, the effect of mosquito and host passage on in vitro var gene transcription was investigated. Methods. Thirty malaria-naive individuals were inoculated by intradermal or intravenous injection with cryopreserved, isogenic NF54 P. falciparum sporozoites (PfSPZ) generated from 1 premosquito culture. Microscopic parasitemia developed in 22 individuals, and 21 in vitro cultures were established. The var gene transcript levels were determined in early and late postpatient cultures and in the premosquito culture. Results. At the early time point, all cultures preferentially transcribed 8 subtelomeric var genes. Intradermal infections had higher var gene transcript levels than intravenous infections and a significantly longer intrahost replication time (P = .03). At the late time point, 9 subtelomeric and 8 central var genes were transcribed at the same levels in almost all cultures. Premosquito and late postpatient cultures transcribed the same subtelomeric and central var genes, except for var2csa. Conclusions. The duration of intrahost replication influences in vitro var gene transcript patterns. Differences between premosquito and postpatient cultures decrease with prolonged in vitro growth. PMID:27279526

  8. Automated estimation of parasitaemia of Plasmodium yoelii-infected mice by digital image analysis of Giemsa-stained thin blood smears.

    PubMed

    Ma, Charles; Harrison, Paul; Wang, Lina; Coppel, Ross L

    2010-12-01

    Parasitaemia, the percentage of infected erythrocytes, is used to measure progress of experimental Plasmodium infection in infected hosts. The most widely used technique for parasitaemia determination is manual microscopic enumeration of Giemsa-stained blood films. This process is onerous, time consuming and relies on the expertise of the experimenter giving rise to person-to-person variability. Here the development of image-analysis software, named Plasmodium AutoCount, which can automatically generate parasitaemia values from Plasmodium-infected blood smears, is reported. Giemsa-stained blood smear images were captured with a camera attached to a microscope and analysed using a programme written in the Python programming language. The programme design involved foreground detection, cell and infection detection, and spurious hit filtering. A number of parameters were adjusted by a calibration process using a set of representative images. Another programme, Counting Aid, written in Visual Basic, was developed to aid manual counting when the quality of blood smear preparation is too poor for use with the automated programme. This programme has been validated for use in estimation of parasitemia in mouse infection by Plasmodium yoelii and used to monitor parasitaemia on a daily basis for an entire challenge infection. The parasitaemia values determined by Plasmodium AutoCount were shown to be highly correlated with the results obtained by manual counting, and the discrepancy between automated and manual counting results were comparable to those found among manual counts of different experimenters. Plasmodium AutoCount has proven to be a useful tool for rapid and accurate determination of parasitaemia from infected mouse blood. For greater accuracy when smear quality is poor, Plasmodium AutoCount, can be used in conjunction with Counting Aid.

  9. Comparison of Imported Plasmodium ovale curtisi and P. ovale wallikeri Infections among Patients in Spain, 2005–2011

    PubMed Central

    Rubio-Muñoz, José Miguel; Ramírez-Olivencia, Germán; García-Bujalance, Silvia; Elcuaz-Romano, Rosa; Díaz-Menéndez, Marta; Calderón, María; García-Bermejo, Isabel; Ruiz-Giardín, José Manuel; Merino-Fernández, Francisco Jesús; Torrús-Tendero, Diego; Delgado-Iribarren, Alberto; Ribell-Bachs, Mónica; Arévalo-Serrano, Juan; Cuadros-González, Juan

    2014-01-01

    Sequencing data from Plasmodium ovale genotypes co-circulating in multiple countries support the hypothesis that P. ovale curtisi and P. ovale wallikeri are 2 separate species. We conducted a multicenter, retrospective, comparative study in Spain of 21 patients who had imported P. ovale curtisi infections and 14 who had imported P. ovale wallikeri infections confirmed by PCR and gene sequencing during June 2005–December 2011. The only significant finding was more severe thrombocytopenia among patients with P. ovale wallikeri infection than among those with P. ovale curtisi infection (p = 0.031). However, we also found nonsignificant trends showing that patients with P. ovale wallikeri infection had shorter time from arrival in Spain to onset of symptoms, lower level of albumin, higher median maximum core temperature, and more markers of hemolysis than did those with P. ovale curtisi infection. Larger, prospective studies are needed to confirm these findings. PMID:24572501

  10. In Vivo Antimalarial Activity of Annona muricata Leaf Extract in Mice Infected with Plasmodium berghei.

    PubMed

    Somsak, Voravuth; Polwiang, Natsuda; Chachiyo, Sukanya

    2016-01-01

    Malaria is one of the most important infectious diseases in the world. The choice for the treatment is highly limited due to drug resistance. Hence, finding the new compounds to treat malaria is urgently needed. The present study was attempted to evaluate the antimalarial activity of the Annona muricata aqueous leaf extract in Plasmodium berghei infected mice. Aqueous leaf extract of A. muricata was prepared and tested for acute toxicity in mice. For efficacy test in vivo, standard 4-day suppressive test was carried out. ICR mice were inoculated with 10(7) parasitized erythrocytes of P. berghei ANKA by intraperitoneal injection. The extracts (100, 500, and 1000 mg/kg) were then given orally by gavage once a day for 4 consecutive days. Parasitemia, percentage of inhibition, and packed cell volume were subsequently calculated. Chloroquine (10 mg/kg) was given to infected mice as positive control while untreated control was given only distilled water. It was found that A. muricata aqueous leaf extract at doses of 100, 500, and 1000 mg/kg resulted in dose dependent parasitemia inhibition of 38.03%, 75.25%, and 85.61%, respectively. Survival time was prolonged in infected mice treated with the extract. Moreover, no mortality to mice was observed with this extract up to a dose of 4000 mg/kg. In conclusion, the A. muricata aqueous leaf extract exerted significant antimalarial activity with no toxicity and prolonged survival time. Therefore, this extract might contain potential lead molecule for the development of a new drug for malaria treatment.

  11. In Vivo Antimalarial Activity of Annona muricata Leaf Extract in Mice Infected with Plasmodium berghei

    PubMed Central

    Somsak, Voravuth; Polwiang, Natsuda; Chachiyo, Sukanya

    2016-01-01

    Malaria is one of the most important infectious diseases in the world. The choice for the treatment is highly limited due to drug resistance. Hence, finding the new compounds to treat malaria is urgently needed. The present study was attempted to evaluate the antimalarial activity of the Annona muricata aqueous leaf extract in Plasmodium berghei infected mice. Aqueous leaf extract of A. muricata was prepared and tested for acute toxicity in mice. For efficacy test in vivo, standard 4-day suppressive test was carried out. ICR mice were inoculated with 107 parasitized erythrocytes of P. berghei ANKA by intraperitoneal injection. The extracts (100, 500, and 1000 mg/kg) were then given orally by gavage once a day for 4 consecutive days. Parasitemia, percentage of inhibition, and packed cell volume were subsequently calculated. Chloroquine (10 mg/kg) was given to infected mice as positive control while untreated control was given only distilled water. It was found that A. muricata aqueous leaf extract at doses of 100, 500, and 1000 mg/kg resulted in dose dependent parasitemia inhibition of 38.03%, 75.25%, and 85.61%, respectively. Survival time was prolonged in infected mice treated with the extract. Moreover, no mortality to mice was observed with this extract up to a dose of 4000 mg/kg. In conclusion, the A. muricata aqueous leaf extract exerted significant antimalarial activity with no toxicity and prolonged survival time. Therefore, this extract might contain potential lead molecule for the development of a new drug for malaria treatment. PMID:27092277

  12. Genetic diversity and multiplicity of infection of Plasmodium falciparum isolates from Kolkata, West Bengal, India.

    PubMed

    Saha, Pabitra; Ganguly, Swagata; Maji, Ardhendu K

    2016-09-01

    The study of genetic diversity of Plasmodium falciparum is necessary to understand the distribution and dynamics of parasite populations. The genetic diversity of P. falciparum merozoite surface protein-1 and 2 has been extensively studied from different parts of world. However, limited data are available from India. This study was aimed to determine the genetic diversity and multiplicity of infection (MOI) of P. falciparum population in Kolkata, West Bengal, India. A total of 80day-zero blood samples from Kolkata were collected during a therapeutic efficacy study in 2008-2009. DNA was extracted; allelic frequency and diversity were investigated by PCR-genotyping method for msp1 and msp2 gene and fragment sizing was done by Bio-Rad Gel-Doc system using Image Lab (version 4.1) software. P. falciparum msp1 and msp2 markers were highly polymorphic with low allele frequencies. In Kolkata, 27 msp1 different genotypes (including 11of K1, 6 of MAD20 and 10 of Ro33 allelic families) and 30 different msp2 genotypes (of which 17 and 13 belonged to the FC27 and 3D7 allelic families, respectively) were recorded. The majority of these genotypes occurred at a frequency below 10%. The mean MOI for msp1 and msp2 gene were 2.05 and 3.72, respectively. The P. falciparum population of Kolkata was genetically diverse. As the frequencies of most of the msp1 and msp2 alleles were low, the probability of new infection with genotype identical to that in pretreatment infection was very rare. This information will serve as baseline data for evaluation of malaria control interventions as well as for monitoring the parasite population structure.

  13. Separation of Plasmodium falciparum Late Stage-infected Erythrocytes by Magnetic Means

    PubMed Central

    Coronado, Lorena Michelle; Tayler, Nicole Michelle; Correa, Ricardo; Giovani, Rita Marissa; Spadafora, Carmenza

    2013-01-01

    Unlike other Plasmodium species, P. falciparum can be cultured in the lab, which facilitates its study 1. While the parasitemia achieved can reach the ≈40% limit, the investigator usually keeps the percentage at around 10%. In many cases it is necessary to isolate the parasite-containing red blood cells (RBCs) from the uninfected ones, to enrich the culture and proceed with a given experiment. When P. falciparum infects the erythrocyte, the parasite degrades and feeds from haemoglobin 2, 3. However, the parasite must deal with a very toxic iron-containing haem moiety 4, 5. The parasite eludes its toxicity by transforming the haem into an inert crystal polymer called haemozoin 6, 7. This iron-containing molecule is stored in its food vacuole and the metal in it has an oxidative state which differs from the one in haem 8. The ferric state of iron in the haemozoin confers on it a paramagnetic property absent in uninfected erythrocytes. As the invading parasite reaches maturity, the content of haemozoin also increases 9, which bestows even more paramagnetism on the latest stages of P. falciparum inside the erythrocyte. Based on this paramagnetic property, the latest stages of P. falciparum infected-red blood cells can be separated by passing the culture through a column containing magnetic beads. These beads become magnetic when the columns containing them are placed on a magnet holder. Infected RBCs, due to their paramagnetism, will then be trapped inside the column, while the flow-through will contain, for the most part, uninfected erythrocytes and those containing early stages of the parasite. Here, we describe the methodology to enrich the population of late stage parasites with magnetic columns, which maintains good parasite viability 10. After performing this procedure, the unattached culture can be returned to an incubator to allow the remaining parasites to continue growing. PMID:23486405

  14. An automated method for determining the cytoadhesion of Plasmodium falciparum-infected erythrocytes to immobilized cells.

    PubMed

    Hempel, Casper; Boisen, Ida M; Efunshile, Akinwale; Kurtzhals, Jørgen A L; Staalsø, Trine

    2015-03-14

    Plasmodium falciparum exports antigens to the surface of infected erythrocytes causing cytoadhesion to the host vasculature. This is central in malaria pathogenesis but in vitro studies of cytoadhesion rely mainly on manual counting methods. The current study aimed at developing an automated high-throughput method for this purpose utilizing the pseudoperoxidase activity of intra-erythrocytic haemoglobin. Chinese hamster ovary (CHO) cells were grown to confluence in chamber slides and microtiter plates. Cytoadhesion of co-cultured P. falciparum, selected for binding to CHO cells, was quantified by microscopy of Giemsa-stained chamber slides. In the automated assay, binding was quantified spectrophotometrically in microtiter plates after cell lysis using tetramethylbenzidine as peroxidase-catalysed substrate. The relevance of the method for binding studies was assessed using: i) binding of P. falciparum-infected erythrocytes to CHO cells over-expressing chondroitin sulfate A and ii) CHO cells transfected with CD36. Binding of infected erythrocytes including field isolates to primary endothelial cells was also performed. Data was analysed using linear regression and Bland-Altman plots. The manual and automated quantification showed strong, positive correlation (r(2) = 0.959, p <0.001) and with similar detection limit and precision. The automated assay showed the expected dose-dependent reduction in binding to CHO cells when blocking with soluble chondroitin sulfate A or anti-CD36 antibody. Quantification of binding to endothelial cells showed clear distinction between selected vs. non-selected parasite lines. Importantly, the assay was sufficiently sensitive to detect adhesion of field isolates to endothelial cells. The assay is simple and in a reproducible manner quantifies erythrocyte adhesion to several types of immobilized cells.

  15. Sulfadoxine-pyrimethamine impairs Plasmodium falciparum gametocyte infectivity and Anopheles mosquito survival

    PubMed Central

    Kone, Aminatou; van de Vegte-Bolmer, Marga; Siebelink-Stoter, Rianne; van Gemert, Geert-Jan; Dara, Antoine; Niangaly, Hamidou; Luty, Adrian; Doumbo, Ogobara K.; Sauerwein, Robert; Djimde, Abdoulaye A

    2013-01-01

    Sulfadoxine-pyrimethamine (SP) is currently the drug of choice for intermittent preventive treatment of Plasmodium falciparum both in pregnancy and infancy. A prolonged parasite clearance time conferred by dhfr and dhps mutations is believed to be responsible for increased gametocyte prevalence in SP treated individuals. However, using a direct feeding assay in Mali, we showed that gametocytes present in peripheral venous blood post-SP treatment had reduced infectivity for Anopheles gambiae sensu stricto (ss) mosquitoes. We investigated the potential mechanisms involved in the dhfr and dhps quintuple mutant NF135 and the single dhps 437 mutant NF54. Concentrations of Sulfadoxine (S) and Pyrimethamine (P) equivalent to the serum levels of the respective drugs on day 3 (S = 61 ug/ml, P = 154.7 ng/ml) day 7 (S = 33.8 ug/ml, P = 66.6 ng/ml) and day 14 (S = 14.2 ug/ml, P = 15.7 ng/ml) post-SP treatment were used to study the effect on gametocytogenesis, gametocyte maturation and infectivity to Anopheles stephensi mosquitoes fed through an artificial membrane. The drugs readily induced gametocytogenesis in the mutant NF-135 strain but effectively killed the wild-type NF54. However, both drugs impaired gametocyte maturation yielding odd-shaped non-exflagelating mature gametocytes. The concomitant ingestion of both S and P together with gametocytemic blood-meal significantly reduced the prevalence of oocyst positivity as well as oocyst density when compared to controls (P < 0.001). In addition, day 3 concentrations of SP decreased mosquito survival by up to 65% (P < 0.001). This study demonstrates that SP is deleterious in vitro for gametocyte infectivity as well as mosquito survival. PMID:20515695

  16. Sulfadoxine-pyrimethamine impairs Plasmodium falciparum gametocyte infectivity and Anopheles mosquito survival.

    PubMed

    Kone, Aminatou; van de Vegte-Bolmer, Marga; Siebelink-Stoter, Rianne; van Gemert, Geert-Jan; Dara, Antoine; Niangaly, Hamidou; Luty, Adrian; Doumbo, Ogobara K; Sauerwein, Robert; Djimde, Abdoulaye A

    2010-08-15

    Sulfadoxine-pyrimethamine (SP) is currently the drug of choice for intermittent preventive treatment of Plasmodium falciparum both in pregnancy and infancy. A prolonged parasite clearance time conferred by dhfr and dhps mutations is believed to be responsible for increased gametocyte prevalence in SP treated individuals. However, using a direct feeding assay in Mali, we showed that gametocytes present in peripheral venous blood post-SP treatment had reduced infectivity for Anopheles gambiae sensu stricto (ss) mosquitoes. We investigated the potential mechanisms involved in the dhfr and dhps quintuple mutant NF-135 and the single dhps 437 mutant NF-54. Concentrations of sulfadoxine (S) and pyrimethamine (P) equivalent to the serum levels of the respective drugs on day 3 (S=61 microg/ml, P=154.7 ng/ml) day 7 (S=33.8 microg/ml, P=66.6 ng/ml) and day 14 (S=14.2 microg/ml, P=15.7 ng/ml) post-SP treatment were used to study the effect on gametocytogenesis, gametocyte maturation and infectivity to Anopheles stephensi mosquitoes fed through an artificial membrane. The drugs readily induced gametocytogenesis in the mutant NF-135 strain but effectively killed the wild-type NF-54. However, both drugs impaired gametocyte maturation yielding odd-shaped non-exflagellating mature gametocytes. The concomitant ingestion of both S and P together with gametocytemic blood-meal significantly reduced the prevalence of oocyst positivity as well as oocyst density when compared to controls (P<0.001). In addition, day 3 concentrations of SP decreased mosquito survival by up to 65% (P<0.001). This study demonstrates that SP is deleterious in vitro for gametocyte infectivity as well as mosquito survival. Copyright 2010. Published by Elsevier Ltd.

  17. Mosquito Feeding Assays to Determine the Infectiousness of Naturally Infected Plasmodium falciparum Gametocyte Carriers

    PubMed Central

    Bousema, Teun; Dinglasan, Rhoel R.; Morlais, Isabelle; Gouagna, Louis C.; van Warmerdam, Travis; Awono-Ambene, Parfait H.; Bonnet, Sarah; Diallo, Mouctar; Coulibaly, Mamadou; Tchuinkam, Timoléon; Mulder, Bert; Targett, Geoff; Drakeley, Chris; Sutherland, Colin; Robert, Vincent; Doumbo, Ogobara; Touré, Yeya; Graves, Patricia M.; Roeffen, Will; Sauerwein, Robert; Birkett, Ashley; Locke, Emily; Morin, Merribeth; Wu, Yimin; Churcher, Thomas S.

    2012-01-01

    Introduction In the era of malaria elimination and eradication, drug-based and vaccine-based approaches to reduce malaria transmission are receiving greater attention. Such interventions require assays that reliably measure the transmission of Plasmodium from humans to Anopheles mosquitoes. Methods We compared two commonly used mosquito feeding assay procedures: direct skin feeding assays and membrane feeding assays. Three conditions under which membrane feeding assays are performed were examined: assays with i) whole blood, ii) blood pellets resuspended with autologous plasma of the gametocyte carrier, and iii) blood pellets resuspended with heterologous control serum. Results 930 transmission experiments from Cameroon, The Gambia, Mali and Senegal were included in the analyses. Direct skin feeding assays resulted in higher mosquito infection rates compared to membrane feeding assays (odds ratio 2.39, 95% confidence interval 1.94–2.95) with evident heterogeneity between studies. Mosquito infection rates in membrane feeding assays and direct skin feeding assays were strongly correlated (p<0.0001). Replacing the plasma of the gametocyte donor with malaria naïve control serum resulted in higher mosquito infection rates compared to own plasma (OR 1.92, 95% CI 1.68–2.19) while the infectiousness of gametocytes may be reduced during the replacement procedure (OR 0.60, 95% CI 0.52–0.70). Conclusions Despite a higher efficiency of direct skin feeding assays, membrane feeding assays appear suitable tools to compare the infectiousness between individuals and to evaluate transmission-reducing interventions. Several aspects of membrane feeding procedures currently lack standardization; this variability makes comparisons between laboratories challenging and should be addressed to facilitate future testing of transmission-reducing interventions. PMID:22936993

  18. Comparing systemic metabolic responses in mice to single or dual infection with Plasmodium berghei and Heligmosomoides bakeri.

    PubMed

    Tritten, Lucienne; Keiser, Jennifer; Karwa, Tasneem; Utzinger, Jürg; Holmes, Elaine; Saric, Jasmina

    2014-07-29

    Concomitant infections with Plasmodium and gastrointestinal nematodes are frequently observed in humans. At the metabolic level, the cross-talk between the host and multiple coexisting pathogens is poorly characterized. The purpose of this study was to give a comprehensive insight into the systemic metabolic phenotype of mice with a single or dual infection with Plasmodium berghei and Heligmosomoides bakeri. Four groups of eight NMRI female mice were infected with P. berghei or H. bakeri, or with both species concurrently. An additional group remained uninfected, and served as control. Mice were sacrificed at day 19 of the experiment. We collected samples from the liver, spleen, kidney, three intestinal regions, and four brain regions. All biological samples were subjected to (1)H nuclear magnetic resonance spectroscopy, combined with multivariate data analysis, to establish metabolic fingerprints of each tissue from the various infection groups. Compared to uninfected mice, single and dual species infection models showed unique metabolic profiles. P. berghei exerted major effects on glycolysis, tricarboxylic acid cycle, and nucleotide and amino acid metabolism in all studied tissues with the exception of the gut. H. bakeri was characterized by a dysregulation of choline and lipid metabolism in most tissues examined with a particularly strong imprint in the jejunum. Simultaneous co-infection with P. berghei and H. bakeri induced the strongest and most diverse effects in the liver and spleen but led to only minor changes in the intestinal and cerebral parts assessed. Infection with P. berghei showed more pronounced and systemic alterations in the mice metabolic profile than H. bakeri infection. The metabolic fingerprints in the co-infection models were driven by P. berghei infection, whilst the presence of H. bakeri in co-infections had little effect. However, simultaneous co-infection showed indeed the least metabolic disruptions in the peripheral tissues, namely

  19. Establishment of a murine model of cerebral malaria in KunMing mice infected with Plasmodium berghei ANKA.

    PubMed

    Ding, Yan; Xu, Wenyue; Zhou, Taoli; Liu, Taiping; Zheng, Hong; Fu, Yong

    2016-10-01

    Malaria remains one of the most devastating diseases. Cerebral malaria (CM) is a severe complication of Plasmodium falciparum infection resulting in high mortality and morbidity worldwide. Analysis of precise mechanisms of CM in humans is difficult for ethical reasons and animal models of CM have been employed to study malaria pathogenesis. Here, we describe a new experimental cerebral malaria (ECM) model with Plasmodium berghei ANKA infection in KunMing (KM) mice. KM mice developed ECM after blood-stage or sporozoites infection, and the development of ECM in KM mice has a dose-dependent relationship with sporozoites inoculums. Histopathological findings revealed important features associated with ECM, including accumulation of mononuclear cells and red blood cells in brain microvascular, and brain parenchymal haemorrhages. Blood-brain barrier (BBB) examination showed that BBB disruption was present in infected KM mice when displaying clinical signs of CM. In vivo bioluminescent imaging experiment indicated that parasitized red blood cells accumulated in most vital organs including heart, lung, spleen, kidney, liver and brain. The levels of inflammatory cytokines interferon-gamma, tumour necrosis factor-alpha, interleukin (IL)-17, IL-12, IL-6 and IL-10 were all remarkably increased in KM mice infected with P. berghei ANKA. This study indicates that P. berghei ANKA infection in KM mice can be used as ECM model to extend further research on genetic, pharmacological and vaccine studies of CM.

  20. An Intensive Longitudinal Cohort Study of Malian Children and Adults Reveals No Evidence of Acquired Immunity to Plasmodium falciparum Infection

    PubMed Central

    Tran, Tuan M.; Li, Shanping; Doumbo, Safiatou; Doumtabe, Didier; Huang, Chiung-Yu; Dia, Seydou; Bathily, Aboudramane; Sangala, Jules; Kone, Younoussou; Traore, Abdrahamane; Niangaly, Moussa; Dara, Charles; Kayentao, Kassoum; Ongoiba, Aissata; Doumbo, Ogobara K.; Traore, Boubacar; Crompton, Peter D.

    2013-01-01

    Background In experimental models of human and mouse malaria, sterilizing liver stage immunity that blocks progression of Plasmodium infection to the symptomatic blood stage can be readily demonstrated. However, it remains unclear whether individuals in malaria-endemic areas acquire such immunity. Methods In Mali, 251 healthy children and adults aged 4–25 years who were free of blood-stage Plasmodium infection by polymerase chain reaction (PCR) were enrolled in a longitudinal study just prior to an intense 6-month malaria season. Subsequent clinical malaria episodes were detected by weekly active surveillance and self-referral. Asymptomatic P. falciparum infections were detected by blood-smear microscopy and PCR analysis of dried blood spots that had been collected every 2 weeks for 7 months. Results As expected, the risk of clinical malaria decreased with increasing age (log-rank test, P = .0038). However, analysis of PCR data showed no age-related differences in P. falciparum infection risk (log-rank test, P = .37). Conclusions Despite years of exposure to intense P. falciparum transmission, there is no evidence of acquired, sterile immunity to P. falciparum infection in this population, even as clinical immunity to blood-stage malaria is clearly acquired. Understanding why repeated P. falciparum infections do not induce sterile protection may lead to insights for developing vaccines that target the liver stage in malaria-endemic populations. PMID:23487390

  1. Therapeutic efficacy of chloroquine and sulfadoxine/pyrimethamine against Plasmodium falciparum infection in Somalia.

    PubMed Central

    Warsame, M.; Abdillahi, A.; Duale, O. Nur; Ismail, A. Nur; Hassan, A. M.; Mohamed, A.; Warsame, A.

    2002-01-01

    OBJECTIVE: To assess the efficacy of chloroquine and sulfadoxine/pyrimethamine in the treatment of uncomplicated Plasmodium falciparum infections in Somalia. METHODS: Patients with clinical malaria in Merca, an area of high transmission of the disease, were treated with the standard regimens of chloroquine (25 mg/kg) or sulfadoxine/pyrimethamine (25 mg sulfadoxine and 1.25 mg pyrimethamine per kg). Similar patients in Gabiley, an area of low transmission, received the standard regimen of chloroquine. The clinical and parasitological responses were monitored for 14 days. FINDINGS: Chloroquine treatment resulted in clinical failure in 33% (n = 60) and 51% (n = 49) of the patients in Merca and Gabiley respectively. There were corresponding parasitological failures of 77% RII/RIII and 35% RII/RIII. Patients who experienced clinical failure had significantly higher initial parasitaemia than those in whom there was an adequate clinical response, both in Merca (t = 2.2; P t = 2.8; P n = 50) of the patients achieved an adequate clinical response despite a parasitological failure rate of 76% RII/RIII. CONCLUSION: Chloroquine should no longer be considered adequate for treating clinical falciparum malaria in vulnerable groups in the areas studied. Doubts about the therapeutic life of sulfadoxine/pyrimethamine in relation to malaria are raised by the high levels of resistance in the Merca area and underline the need to identify suitable alternatives. PMID:12378287

  2. Defective sorting of the thrombospondin-related anonymous protein (TRAP) inhibits Plasmodium infectivity.

    PubMed

    Bhanot, Purnima; Frevert, Ute; Nussenzweig, Victor; Persson, Cathrine

    2003-02-01

    Thrombospondin-related anonymous protein (TRAP) is a type 1 transmembrane protein that plays an essential role in gliding motility and cell invasion by Plasmodium sporozoites. It is stored in micronemes-secretory organelles located primarily in the apical end of the parasites and is also found on the parasite surface. The mechanisms that target TRAP and other sporozoite proteins to micronemes and subsequently to the parasite surface are not known. Here we report that the micronemal and surface localization of TRAP requires a tyrosine-based motif located in its cytoplasmic tail. This motif is analogous to the YXXphi motif (Y: tyrosine, X: any amino acid; phi: hydrophobic amino acid) that targets eukaryotic proteins to certain sub-cellular compartments and to the plasma membrane. Abrogating the Y motif substantially reduces micronemal and cell surface localization of TRAP. The infectivity of mutant parasites is substantially inhibited. However, there is no significant difference in the amounts of TRAP secreted into the culture medium by wild type and mutant parasites, suggesting that TRAP destined for secretion bypasses micronemal localization.

  3. Cytoadhesion of Plasmodium falciparum–infected erythrocytes to chondroitin-4-sulfate is cooperative and shear enhanced

    PubMed Central

    Rieger, Harden; Yoshikawa, Hiroshi Y.; Quadt, Katharina; Nielsen, Morten A.; Sanchez, Cecilia P.; Salanti, Ali

    2015-01-01

    Infections with the human malaria parasite Plasmodium falciparum during pregnancy can lead to severe complications for both mother and child, resulting from the cytoadhesion of parasitized erythrocytes in the intervillous space of the placenta. Cytoadherence is conferred by the specific interaction of the parasite-encoded adhesin VAR2CSA with chondroitin-4-sulfate (CSA) present on placental proteoglycans. CSA presented elsewhere in the microvasculature does not afford VAR2CSA-mediated cytoadhesion of parasitized erythrocytes. To address the placenta-specific binding tropism, we investigated the effect of the receptor/ligand arrangement on cytoadhesion, using artificial membranes with different CSA spacing intervals. We found that cytoadhesion is strongly dependent on the CSA distance, with half-maximal adhesion occurring at a CSA distance of 9 ± 1 nm at all hydrodynamic conditions. Moreover, binding to CSA was cooperative and shear stress induced. These findings suggest that the CSA density, together with allosteric effects in VAR2CSA, aid in discriminating between different CSA milieus. PMID:25352129

  4. Whole blood chloroquine concentrations with Plasmodium vivax infection in Irian Jaya, Indonesia.

    PubMed

    Baird, J K; Leksana, B; Masbar, S; Suradi; Sutanihardja, M A; Fryauff, D J; Subianto, B

    1997-06-01

    Whole blood concentrations of self-administered chloroquine (CQ) and its metabolite desethylchloroquine (DCQ) were measured in 168 patients with microscopically confirmed infection by Plasmodium vivax in northeastern Irian Jaya, Indonesia. The study consisted of both survey and passive case detection in four separate villages between 1992 and 1994. The subjects were Javanese people 4-51 years old who had lived in the Arso region for up to two years. The sum of CQ and DCQ ranged from 0 to 8,342 ng/ml of whole blood, and 122 subjects (73%) had > or = 100 ng/ml of CQ plus DCQ, the estimated minimally effective concentration (MEC) in whole blood against chloroquine-sensitive P. vivax. Among 56 subjects reporting to a clinic with symptoms of malaria, 53 (95%) had ordinarily effective levels of chloroquine in blood. Among 109 largely asymptomatic malaria patients found by survey case detection, 69 (63%) had chloroquine blood levels greater than the MEC. Virtually all clinical and most subclinical vivax malaria in this region occurs despite ordinarily effective levels of chloroquine in blood.

  5. Quantitative imaging of human red blood cells infected with Plasmodium falciparum.

    PubMed

    Esposito, Alessandro; Choimet, Jean-Baptiste; Skepper, Jeremy N; Mauritz, Jakob M A; Lew, Virgilio L; Kaminski, Clemens F; Tiffert, Teresa

    2010-08-04

    During its 48 h asexual reproduction cycle, the malaria parasite Plasmodium falciparum ingests and digests hemoglobin in excess of its metabolic requirements and causes major changes in the homeostasis of the host red blood cell (RBC). A numerical model suggested that this puzzling excess consumption of hemoglobin is necessary for the parasite to reduce the colloidosmotic pressure within the host RBC, thus preventing lysis before completion of its reproduction cycle. However, the validity of the colloidosmotic hypothesis appeared to be compromised by initial conflicts between model volume predictions and experimental observations. Here, we investigated volume and membrane area changes in infected RBCs (IRBCs) using fluorescence confocal microscopy on calcein-loaded RBCs. Substantial effort was devoted to developing and testing a new threshold-independent algorithm for the precise estimation of cell volumes and surface areas to overcome the shortfalls of traditional methods. We confirm that the volume of IRBCs remains almost constant during parasite maturation, suggesting that the reported increase in IRBCs' osmotic fragility results from a reduction in surface area and increased lytic propensity on volume expansion. These results support the general validity of the colloidosmotic hypothesis, settle the IRBC volume debate, and help to constrain the range of parameter values in the numerical model. 2010 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  6. Plasmodium berghei infection: dichloroacetate improves survival in rats with lactic acidosis.

    PubMed

    Holloway, P A; Knox, K; Bajaj, N; Chapman, D; White, N J; O'Brien, R; Stacpoole, P W; Krishna, S

    1995-06-01

    The kinetics of Plasmodium berghei infection and the development of lactic acidosis, hypoglycemia, and anemia were defined in young Wistar rats. This model of metabolic dysfunction, which is similar to that of severe human malaria, was used to test the hypothesis that dichloroacetate, a treatment for lactic acidosis, prolonged survival in rats receiving a single antimalarial dose of quinine (20 mg/kg). Rats with hyperlactatemia (lactate > 5 mmol/liter, N = 183) were randomized to receive either dichloroacetate (100 mg/kg, N = 99) or saline (N = 84) and were monitored for outcome (survival or death) for 50 hr. Logistic regression modeling adjusting for baseline venous lactate concentration demonstrated that dichloroacetate increases survival rates in rats with venous lactate concentrations between 5 and 8.9 mmol/liter (odds ratio > 2.2, P < 0.021). This is the first demonstration that specific intervention to treat lactic acidosis can prolong survival and suggests that dichloroacetate may be useful as adjunctive therapy in the management of lactic acidosis complicating severe falciparum malaria.

  7. Quantitative pH measurements in Plasmodium falciparum-infected erythrocytes using pHluorin.

    PubMed

    Kuhn, Yvonne; Rohrbach, Petra; Lanzer, Michael

    2007-04-01

    The digestive vacuole of the malaria parasite Plasmodium falciparum is the site of action of several antimalarial drugs, such as chloroquine, which accumulate in this organelle due to their properties as amphiphilic weak bases that inhibit haem detoxification. It has been suggested that changes in the pH of the digestive vacuole, affecting either drug partitioning or haem solubility and/or biomineralization rates, would correlate with reduced intracellular chloroquine accumulation and, hence, would determine the chloroquine-resistance phenotype. The techniques previously used to quantify digestive vacuolar pH mainly relied on lysed or isolated parasites, with unpredictable consequences on internal pH homeostasis. In this study, we have investigated the baseline steady-state pH of the cytoplasm and digestive vacuole of a chloroquine-sensitive (HB3) and a chloroquine-resistant (Dd2) parasite using a pH-sensitive green fluorescent protein, termed pHluorin. This non-invasive technique allows for in vivo pH measurements in intact P. falciparum-infected erythrocytes under physiological conditions. The data suggest that the pH of the cytoplasm is approximately 7.15 +/- 0.07 and that of the digestive vacuole approximately 5.18 +/- 0.05. No significant differences in baseline pH values were recorded for the chloroquine-sensitive and chloroquine-resistant parasites.

  8. Analysis of Plasmodium falciparum diversity in natural infections by deep sequencing.

    PubMed

    Manske, Magnus; Miotto, Olivo; Campino, Susana; Auburn, Sarah; Almagro-Garcia, Jacob; Maslen, Gareth; O'Brien, Jack; Djimde, Abdoulaye; Doumbo, Ogobara; Zongo, Issaka; Ouedraogo, Jean-Bosco; Michon, Pascal; Mueller, Ivo; Siba, Peter; Nzila, Alexis; Borrmann, Steffen; Kiara, Steven M; Marsh, Kevin; Jiang, Hongying; Su, Xin-Zhuan; Amaratunga, Chanaki; Fairhurst, Rick; Socheat, Duong; Nosten, Francois; Imwong, Mallika; White, Nicholas J; Sanders, Mandy; Anastasi, Elisa; Alcock, Dan; Drury, Eleanor; Oyola, Samuel; Quail, Michael A; Turner, Daniel J; Ruano-Rubio, Valentin; Jyothi, Dushyanth; Amenga-Etego, Lucas; Hubbart, Christina; Jeffreys, Anna; Rowlands, Kate; Sutherland, Colin; Roper, Cally; Mangano, Valentina; Modiano, David; Tan, John C; Ferdig, Michael T; Amambua-Ngwa, Alfred; Conway, David J; Takala-Harrison, Shannon; Plowe, Christopher V; Rayner, Julian C; Rockett, Kirk A; Clark, Taane G; Newbold, Chris I; Berriman, Matthew; MacInnis, Bronwyn; Kwiatkowski, Dominic P

    2012-07-19

    Malaria elimination strategies require surveillance of the parasite population for genetic changes that demand a public health response, such as new forms of drug resistance. Here we describe methods for the large-scale analysis of genetic variation in Plasmodium falciparum by deep sequencing of parasite DNA obtained from the blood of patients with malaria, either directly or after short-term culture. Analysis of 86,158 exonic single nucleotide polymorphisms that passed genotyping quality control in 227 samples from Africa, Asia and Oceania provides genome-wide estimates of allele frequency distribution, population structure and linkage disequilibrium. By comparing the genetic diversity of individual infections with that of the local parasite population, we derive a metric of within-host diversity that is related to the level of inbreeding in the population. An open-access web application has been established for the exploration of regional differences in allele frequency and of highly differentiated loci in the P. falciparum genome.

  9. Comparison of PCR-based detection of Plasmodium falciparum infections based on single and multicopy genes

    PubMed Central

    Oyedeji, Segun I; Awobode, Henrietta O; Monday, Gamaliel C; Kendjo, Eric; Kremsner, Peter G; Kun, Jürgen F

    2007-01-01

    PCR-based assays are the most sensitive and specific methods to detect malaria parasites. This study compared the diagnostic accuracy of three PCR-based assays that do not only differ in their sequence target, but also in the number of copies of their target region, for the detection of Plasmodium falciparum in 401 individuals living in a malaria-endemic area in Nigeria. Compared to a composite reference generated from results of all the 3 PCR assays, the stevor gene amplification had a sensitivity of 100% (Kappa = 1; 95% CI = 1.000–1.000), 83% (Kappa = 0.718; 95% CI = 0.648–0.788) by SSUrRNA gene PCR and 71% (Kappa = 0.552; 95% CI = 0.478–0.627) by the msa-2 gene amplification. Results from this study indicate that the stevor gene amplification is the most sensitive technique for the detection of P. falciparum. This assay may be an important reference standard, especially when a confirmatory technique with high sensitivity and specificity is needed for ruling out P. falciparum infection. PMID:17705826

  10. Multifaceted Role of Heme during Severe Plasmodium falciparum Infections in India

    PubMed Central

    Dalko, Esther; Das, Bidyut; Herbert, Fabien; Fesel, Constantin; Pathak, Sulabha; Tripathy, Rina; Cazenave, Pierre-André; Ravindran, Balachandran; Sharma, Shobhona

    2015-01-01

    Several immunomodulatory factors are involved in malaria pathogenesis. Among them, heme has been shown to play a role in the pathophysiology of severe malaria in rodents, but its role in human severe malaria remains unclear. Circulating levels of total heme and its main scavenger, hemopexin, along with cytokine/chemokine levels and biological parameters, including hemoglobin and creatinine levels, as well as transaminase activities, were measured in the plasma of 237 Plasmodium falciparum-infected patients living in the state of Odisha, India, where malaria is endemic. All patients were categorized into well-defined groups of mild malaria, cerebral malaria (CM), or severe noncerebral malaria, which included acute renal failure (ARF) and hepatopathy. Our results show a significant increase in total plasma heme levels with malaria severity, especially for CM and malarial ARF. Spearman rank correlation and canonical correlation analyses have shown a correlation between total heme, hemopexin, interleukin-10, tumor necrosis factor alpha, gamma interferon-induced protein 10 (IP-10), and monocyte chemotactic protein 1 (MCP-1) levels. In addition, canonical correlations revealed that heme, along with IP-10, was associated with the CM pathophysiology, whereas both IP-10 and MCP-1 together with heme discriminated ARF. Altogether, our data indicate that heme, in association with cytokines and chemokines, is involved in the pathophysiology of both CM and ARF but through different mechanisms. PMID:26169278

  11. Multifaceted Role of Heme during Severe Plasmodium falciparum Infections in India.

    PubMed

    Dalko, Esther; Das, Bidyut; Herbert, Fabien; Fesel, Constantin; Pathak, Sulabha; Tripathy, Rina; Cazenave, Pierre-André; Ravindran, Balachandran; Sharma, Shobhona; Pied, Sylviane

    2015-10-01

    Several immunomodulatory factors are involved in malaria pathogenesis. Among them, heme has been shown to play a role in the pathophysiology of severe malaria in rodents, but its role in human severe malaria remains unclear. Circulating levels of total heme and its main scavenger, hemopexin, along with cytokine/chemokine levels and biological parameters, including hemoglobin and creatinine levels, as well as transaminase activities, were measured in the plasma of 237 Plasmodium falciparum-infected patients living in the state of Odisha, India, where malaria is endemic. All patients were categorized into well-defined groups of mild malaria, cerebral malaria (CM), or severe noncerebral malaria, which included acute renal failure (ARF) and hepatopathy. Our results show a significant increase in total plasma heme levels with malaria severity, especially for CM and malarial ARF. Spearman rank correlation and canonical correlation analyses have shown a correlation between total heme, hemopexin, interleukin-10, tumor necrosis factor alpha, gamma interferon-induced protein 10 (IP-10), and monocyte chemotactic protein 1 (MCP-1) levels. In addition, canonical correlations revealed that heme, along with IP-10, was associated with the CM pathophysiology, whereas both IP-10 and MCP-1 together with heme discriminated ARF. Altogether, our data indicate that heme, in association with cytokines and chemokines, is involved in the pathophysiology of both CM and ARF but through different mechanisms. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  12. Defining the relationship between infection prevalence and clinical incidence of Plasmodium falciparum malaria

    PubMed Central

    Cameron, Ewan; Battle, Katherine E.; Bhatt, Samir; Weiss, Daniel J.; Bisanzio, Donal; Mappin, Bonnie; Dalrymple, Ursula; Hay, Simon I.; Smith, David L.; Griffin, Jamie T.; Wenger, Edward A.; Eckhoff, Philip A.; Smith, Thomas A.; Penny, Melissa A.; Gething, Peter W.

    2015-01-01

    In many countries health system data remain too weak to accurately enumerate Plasmodium falciparum malaria cases. In response, cartographic approaches have been developed that link maps of infection prevalence with mathematical relationships to predict the incidence rate of clinical malaria. Microsimulation (or ‘agent-based') models represent a powerful new paradigm for defining such relationships; however, differences in model structure and calibration data mean that no consensus yet exists on the optimal form for use in disease-burden estimation. Here we develop a Bayesian statistical procedure combining functional regression-based model emulation with Markov Chain Monte Carlo sampling to calibrate three selected microsimulation models against a purpose-built data set of age-structured prevalence and incidence counts. This allows the generation of ensemble forecasts of the prevalence–incidence relationship stratified by age, transmission seasonality, treatment level and exposure history, from which we predict accelerating returns on investments in large-scale intervention campaigns as transmission and prevalence are progressively reduced. PMID:26348689

  13. Quantitative Imaging of Human Red Blood Cells Infected with Plasmodium falciparum

    PubMed Central

    Esposito, Alessandro; Choimet, Jean-Baptiste; Skepper, Jeremy N.; Mauritz, Jakob M.A.; Lew, Virgilio L.; Kaminski, Clemens F.; Tiffert, Teresa

    2010-01-01

    During its 48 h asexual reproduction cycle, the malaria parasite Plasmodium falciparum ingests and digests hemoglobin in excess of its metabolic requirements and causes major changes in the homeostasis of the host red blood cell (RBC). A numerical model suggested that this puzzling excess consumption of hemoglobin is necessary for the parasite to reduce the colloidosmotic pressure within the host RBC, thus preventing lysis before completion of its reproduction cycle. However, the validity of the colloidosmotic hypothesis appeared to be compromised by initial conflicts between model volume predictions and experimental observations. Here, we investigated volume and membrane area changes in infected RBCs (IRBCs) using fluorescence confocal microscopy on calcein-loaded RBCs. Substantial effort was devoted to developing and testing a new threshold-independent algorithm for the precise estimation of cell volumes and surface areas to overcome the shortfalls of traditional methods. We confirm that the volume of IRBCs remains almost constant during parasite maturation, suggesting that the reported increase in IRBCs' osmotic fragility results from a reduction in surface area and increased lytic propensity on volume expansion. These results support the general validity of the colloidosmotic hypothesis, settle the IRBC volume debate, and help to constrain the range of parameter values in the numerical model. PMID:20682274

  14. SURFIN is a polymorphic antigen expressed on Plasmodium falciparum merozoites and infected erythrocytes

    PubMed Central

    Winter, Gerhard; Kawai, Satoru; Haeggström, Malin; Kaneko, Osamu; von Euler, Anne; Kawazu, Shin-ichiro; Palm, Daniel; Fernandez, Victor; Wahlgren, Mats

    2005-01-01

    The surfaces of the infected erythrocyte (IE) and the merozoite, two developmental stages of malaria parasites, expose antigenic determinants to the host immune system. We report on surface-associated interspersed genes (surf genes), which encode a novel polymorphic protein family, SURFINs, present on both IEs and merozoites. A SURFIN expressed in 3D7 parasites, SURFIN4.2, was identified by mass spectrometric analysis of peptides cleaved off the surface of live IEs with trypsin. SURFINs are encoded by a family of 10 surf genes, including three predicted pseudogenes, located within or close to the subtelomeres of five of the chromosomes. SURFINs show structural and sequence similarities with exported surface-exposed proteins (PvSTP1, PkSICAvar, PvVIR, Pf332, and PfEMP1) of several Plasmodium species. SURFIN4.2 of a parasite other than 3D7 (FCR3S1.2) showed polymorphisms in the extracellular domain, suggesting sequence variability between genotypes. SURFIN4.2 not only was found cotransported with PfEMP1 and RIFIN to the IE surface, but also accumulated in the parasitophorous vacuole. In released merozoites, SURFIN4.2 was present in an amorphous cap at the parasite apex, where it may be involved in the invasion of erythrocytes. By exposing shared polymorphic antigens on IEs and merozoites, the parasite may coordinate the antigenic composition of these attachment surfaces during growth in the bloodstream. PMID:15939796

  15. Hemoglobin S and C affect protein export in Plasmodium falciparum-infected erythrocytes

    PubMed Central

    Kilian, Nicole; Srismith, Sirikamol; Dittmer, Martin; Ouermi, Djeneba; Bisseye, Cyrille; Simpore, Jacques; Cyrklaff, Marek; Sanchez, Cecilia P.; Lanzer, Michael

    2015-01-01

    ABSTRACT Malaria is a potentially deadly disease. However, not every infected person develops severe symptoms. Some people are protected by naturally occurring mechanisms that frequently involve inheritable modifications in their hemoglobin. The best studied protective hemoglobins are the sickle cell hemoglobin (HbS) and hemoglobin C (HbC) which both result from a single amino acid substitution in β-globin: glutamic acid at position 6 is replaced by valine or lysine, respectively. How these hemoglobinopathies protect from severe malaria is only partly understood. Models currently proposed in the literature include reduced disease-mediating cytoadherence of parasitized hemoglobinopathic erythrocytes, impaired intraerythrocytic development of the parasite, dampened inflammatory responses, or a combination thereof. Using a conditional protein export system and tightly synchronized Plasmodium falciparum cultures, we now show that export of parasite-encoded proteins across the parasitophorous vacuolar membrane is delayed, slower, and reduced in amount in hemoglobinopathic erythrocytes as compared to parasitized wild type red blood cells. Impaired protein export affects proteins targeted to the host cell cytoplasm, Maurer's clefts, and the host cell plasma membrane. Impaired protein export into the host cell compartment provides a mechanistic explanation for the reduced cytoadherence phenotype associated with parasitized hemoglobinopathic erythrocytes. PMID:25701664

  16. Microgeographical Differences of Plasmodium vivax Relapse and Re-Infection in the Peruvian Amazon

    PubMed Central

    Chuquiyauri, Raul; Peñataro, Pablo; Brouwer, Kimberly C.; Fasabi, Manuel; Calderon, Maritza; Torres, Sonia; Gilman, Robert H.; Kosek, Margaret; Vinetz, Joseph M.

    2013-01-01

    To determine the magnitude of Plasmodium vivax relapsing malaria in rural Amazonia, we carried out a study in four sites in northeastern Peru. Polymerase chain reaction-restriction fragment length polymorphism of PvMSP-3α and tandem repeat (TR) markers were compared for their ability to distinguish relapse versus reinfection. Of 1,507 subjects with P. vivax malaria, 354 developed > 1 episode during the study; 97 of 354 (27.5%) were defined as relapse using Pvmsp-3α alone. The addition of TR polymorphism analysis significantly reduced the number of definitively defined relapses to 26 of 354 (7.4%) (P < 0.05). Multivariate logistic regression modeling showed that the probability of having > 1 infection was associated with the following: subjects in Mazan (odds ratio [OR] = 2.56; 95% confidence interval [CI] 1.87, 3.51), 15–44 years of age (OR = 1.49; 95% CI 1.03, 2.15), traveling for job purposes (OR = 1.45; 95%CI 1.03, 2.06), and travel within past month (OR = 1.46; 95% CI 1.0, 2.14). The high discriminatory capacity of the molecular tools shown here is useful for understanding the micro-geography of malaria transmission. PMID:23836566

  17. A microfluidic system to study cytoadhesion of Plasmodium falciparum infected erythrocytes to primary brain microvascularendothelial cells

    PubMed Central

    Herricks, Thurston; Seydel, Karl B.; Turner, George; Molyneux, Malcolm; Heyderman, Robert; Taylor, Terrie; Rathod, Pradipsinh K.

    2013-01-01

    The cellular events leading to severe and complicated malaria in some Plasmodium falciparum infections are poorly understood. Additional tools are required to better understand the pathogenesis of this disease. In this technical report, we describe a microfluidic culture system and image processing algorithms that were developed to observe cytoadhesion interactions of P. falciparum parasitized erythrocytes rolling on primary brain microvascularendothelial cells. We isolated and cultured human primary vascular endothelial cells in a closed loop microfluidic culture system where a peristaltic pump and media reservoirs were integrated onto a microscope stage insert. We developed image processing methods to enhance contrast of rolling parasitized erythrocytes on endothelial cells and to estimate the local wall shear stress. The velocity of parasitized erythrocytes rolling on primary brain microvascularendothelial cells was then measured under physiologically relevant wall shear stresses. Finally, we deployed this method successfully at a field site in Blantyre, Malawi. The method is a promising new tool for the investigation of the pathogenesis of severe malaria. PMID:21743938

  18. Cytoplasmic remodeling of erythrocyte raft lipids during infection by the human malaria parasite Plasmodium falciparum

    PubMed Central

    Murphy, Sean C.; Fernandez-Pol, Sebastian; Chung, Paul H.; Prasanna Murthy, S. N.; Milne, Stephen B.; Salomao, Marcela; Brown, H. Alex; Lomasney, Jon W.; Mohandas, Narla

    2007-01-01

    Studies of detergent-resistant membrane (DRM) rafts in mature erythrocytes have facilitated identification of proteins that regulate formation of endovacuolar structures such as the parasitophorous vacuolar membrane (PVM) induced by the malaria parasite Plasmodium falciparum. However, analyses of raft lipids have remained elusive because detergents interfere with lipid detection. Here, we use primaquine to perturb the erythrocyte membrane and induce detergent-free buoyant vesicles, which are enriched in cholesterol and major raft proteins flotillin and stomatin and contain low levels of cytoskeleton, all characteristics of raft microdomains. Lipid mass spectrometry revealed that phosphatidylethanolamine and phosphatidylglycerol are depleted in endovesicles while phosphoinositides are highly enriched, suggesting raft-based endovesiculation can be achieved by simple (non–receptor-mediated) mechanical perturbation of the erythrocyte plasma membrane and results in sorting of inner leaflet phospholipids. Live-cell imaging of lipid-specific protein probes showed that phosphatidylinositol (4,5) bisphosphate (PIP2) is highly concentrated in primaquine-induced vesicles, confirming that it is an erythrocyte raft lipid. However, the malarial PVM lacks PIP2, although another raft lipid, phosphatidylserine, is readily detected. Thus, different remodeling/sorting of cytoplasmic raft phospholipids may occur in distinct endovacuoles. Importantly, erythrocyte raft lipids recruited to the invasion junction by mechanical stimulation may be remodeled by the malaria parasite to establish blood-stage infection. PMID:17526861

  19. Plasmodium vivax but Not Plasmodium falciparum Blood-Stage Infection in Humans Is Associated with the Expansion of a CD8+ T Cell Population with Cytotoxic Potential

    PubMed Central

    Burel, Julie G.; Apte, Simon H.; McCarthy, James S.; Doolan, Denise L.

    2016-01-01

    P. vivax and P. falciparum parasites display different tropism for host cells and induce very different clinical symptoms and pathology, suggesting that the immune responses required for protection may differ between these two species. However, no study has qualitatively compared the immune responses to P. falciparum or P. vivax in humans following primary exposure and infection. Here, we show that the two species differ in terms of the cellular immune responses elicited following primary infection. Specifically, P. vivax induced the expansion of a subset of CD8+ T cells expressing the activation marker CD38, whereas P. falciparum induced the expansion of CD38+ CD4+ T cells. The CD38+ CD8+ T cell population that expanded following P. vivax infection displayed greater cytotoxic potential compared to CD38- CD8+ T cells, and compared to CD38+ CD8+ T cells circulating during P. falciparum infection. We hypothesize that P. vivax infection leads to a stronger CD38+ CD8+ T cell activation because of its preferred tropism for MHC-I-expressing reticulocytes that, unlike mature red blood cells, can present antigen directly to CD8+ T cells. This study provides the first line of evidence to suggest an effector role for CD8+ T cells in P. vivax blood-stage immunity. It is also the first report of species-specific differences in the subset of T cells that are expanded following primary Plasmodium infection, suggesting that malaria vaccine development may require optimization according to the target parasite. Trial Registration anzctr.org.au ACTRN12612000814875; anzctr.org.au ACTRN12613000565741; anzctr.org.au ACTRN12613001040752; ClinicalTrials.gov NCT02281344; anzctr.org.au ACTRN12612001096842; anzctr.org.au ACTRN12613001008718 PMID:27930660

  20. Radical curative efficacy of tafenoquine combination regimens in Plasmodium cynomolgi-infected Rhesus monkeys (Macaca mulatta)

    PubMed Central

    2011-01-01

    Background Tafenoquine is an 8-aminoquinoline being developed for radical cure (blood and liver stage elimination) of Plasmodium vivax. During monotherapy treatment, the compound exhibits slow parasite and fever clearance times, and toxicity in glucose-6-phosphate dehydrogenase (G6PD) deficiency is a concern. Combination with other antimalarials may mitigate these concerns. Methods In 2005, the radical curative efficacy of tafenoquine combinations was investigated in Plasmodium cynomolgi-infected naïve Indian-origin Rhesus monkeys. In the first cohort, groups of two monkeys were treated with a three-day regimen of tafenoquine at different doses alone and in combination with a three-day chloroquine regimen to determine the minimum curative dose (MCD). In the second cohort, the radical curative efficacy of a single-day regimen of tafenoquine-mefloquine was compared to that of two three-day regimens comprising tafenoquine at its MCD with chloroquine or artemether-lumefantrine in groups of six monkeys. In a final cohort, the efficacy of the MCD of tafenoquine against hypnozoites alone and in combination with chloroquine was investigated in groups of six monkeys after quinine pre-treatment to eliminate asexual parasites. Plasma tafenoquine, chloroquine and desethylchloroquine concentrations were determined by LC-MS in order to compare doses of the drugs to those used clinically in humans. Results The total MCD of tafenoquine required in combination regimens for radical cure was ten-fold lower (1.8 mg/kg versus 18 mg/kg) than for monotherapy. This regimen (1.8 mg/kg) was equally efficacious as monotherapy or in combination with chloroquine after quinine pre-treatment to eliminate asexual stages. The same dose of (1.8 mg/kg) was radically curative in combination with artemether-lumefantrine. Tafenoquine was also radically curative when combined with mefloquine. The MCD of tafenoquine monotherapy for radical cure (18 mg/kg) appears to be biologically equivalent to a 600

  1. Radical curative efficacy of tafenoquine combination regimens in Plasmodium cynomolgi-infected Rhesus monkeys (Macaca mulatta).

    PubMed

    Dow, Geoffrey S; Gettayacamin, Montip; Hansukjariya, Pranee; Imerbsin, Rawiwan; Komcharoen, Srawuth; Sattabongkot, Jetsumon; Kyle, Dennis; Milhous, Wilbur; Cozens, Simon; Kenworthy, David; Miller, Anne; Veazey, Jim; Ohrt, Colin

    2011-07-29

    Tafenoquine is an 8-aminoquinoline being developed for radical cure (blood and liver stage elimination) of Plasmodium vivax. During monotherapy treatment, the compound exhibits slow parasite and fever clearance times, and toxicity in glucose-6-phosphate dehydrogenase (G6PD) deficiency is a concern. Combination with other antimalarials may mitigate these concerns. In 2005, the radical curative efficacy of tafenoquine combinations was investigated in Plasmodium cynomolgi-infected naïve Indian-origin Rhesus monkeys. In the first cohort, groups of two monkeys were treated with a three-day regimen of tafenoquine at different doses alone and in combination with a three-day chloroquine regimen to determine the minimum curative dose (MCD). In the second cohort, the radical curative efficacy of a single-day regimen of tafenoquine-mefloquine was compared to that of two three-day regimens comprising tafenoquine at its MCD with chloroquine or artemether-lumefantrine in groups of six monkeys. In a final cohort, the efficacy of the MCD of tafenoquine against hypnozoites alone and in combination with chloroquine was investigated in groups of six monkeys after quinine pre-treatment to eliminate asexual parasites. Plasma tafenoquine, chloroquine and desethylchloroquine concentrations were determined by LC-MS in order to compare doses of the drugs to those used clinically in humans. The total MCD of tafenoquine required in combination regimens for radical cure was ten-fold lower (1.8 mg/kg versus 18 mg/kg) than for monotherapy. This regimen (1.8 mg/kg) was equally efficacious as monotherapy or in combination with chloroquine after quinine pre-treatment to eliminate asexual stages. The same dose of (1.8 mg/kg) was radically curative in combination with artemether-lumefantrine. Tafenoquine was also radically curative when combined with mefloquine. The MCD of tafenoquine monotherapy for radical cure (18 mg/kg) appears to be biologically equivalent to a 600-1200 mg dose in humans. At

  2. Genetic characterization of Hawaiian isolates of Plasmodium relictum reveals mixed-genotype infections

    USGS Publications Warehouse

    Jarvi, S.I.; Farias, M.E.M.; Atkinson, C.T.

    2008-01-01

    Background: The relatively recent introduction of a highly efficient mosquito vector and an avian pathogen (Plasmodium relictum) to an isolated island ecosystem with nai??ve, highly susceptible avian hosts provides a unique opportunity to investigate evolution of virulence in a natural system. Mixed infections can significantly contribute to the uncertainty in host-pathogen dynamics with direct impacts on virulence. Toward further understanding of how host-parasite and parasite-parasite relationships may impact virulence, this study characterizes within-host diversity of malaria parasite populations based on genetic analysis of the trap (thrombospondin-related anonymous protein) gene in isolates originating from Hawaii, Maui and Kauai Islands. Methods: A total of 397 clones were produced by nested PCR amplification and cloning of a 1664 bp fragment of the trap gene from two malarial isolates, K1 (Kauai) and KV115 (Hawaii) that have been used for experimental studies, and from additional isolates from wild birds on Kauai, Maui and Hawaii Islands. Diversity of clones was evaluated initially by RFLP-based screening, followed by complete sequencing of 33 selected clones. Results: RFLP analysis of trap revealed a minimum of 28 distinct RFLP haplotypes among the 397 clones from 18 birds. Multiple trap haplotypes were detected in every bird evaluated, with an average of 5.9 haplotypes per bird. Overall diversity did not differ between the experimental isolates, however, a greater number of unique haplotypes were detected in K1 than in KV115. We detected high levels of clonal diversity with clear delineation between isolates K1 and KV115 in a haplotype network. The patterns of within-host haplotype clustering are consistent with the possibility of a clonal genetic structure and rapid within-host mutation after infection. Conclusion: Avian malaria (P. relictum) and Avipoxvirus are the significant infectious diseases currently affecting the native Hawaiian avifauna. This

  3. Genetic characterization of Hawaiian isolates of Plasmodium relictum reveals mixed-genotype infections

    PubMed Central

    Jarvi, Susan I; Farias, Margaret EM; Atkinson, Carter T

    2008-01-01

    Background The relatively recent introduction of a highly efficient mosquito vector and an avian pathogen (Plasmodium relictum) to an isolated island ecosystem with naïve, highly susceptible avian hosts provides a unique opportunity to investigate evolution of virulence in a natural system. Mixed infections can significantly contribute to the uncertainty in host-pathogen dynamics with direct impacts on virulence. Toward further understanding of how host-parasite and parasite-parasite relationships may impact virulence, this study characterizes within-host diversity of malaria parasite populations based on genetic analysis of the trap (thrombospondin-related anonymous protein) gene in isolates originating from Hawaii, Maui and Kauai Islands. Methods A total of 397 clones were produced by nested PCR amplification and cloning of a 1664 bp fragment of the trap gene from two malarial isolates, K1 (Kauai) and KV115 (Hawaii) that have been used for experimental studies, and from additional isolates from wild birds on Kauai, Maui and Hawaii Islands. Diversity of clones was evaluated initially by RFLP-based screening, followed by complete sequencing of 33 selected clones. Results RFLP analysis of trap revealed a minimum of 28 distinct RFLP haplotypes among the 397 clones from 18 birds. Multiple trap haplotypes were detected in every bird evaluated, with an average of 5.9 haplotypes per bird. Overall diversity did not differ between the experimental isolates, however, a greater number of unique haplotypes were detected in K1 than in KV115. We detected high levels of clonal diversity with clear delineation between isolates K1 and KV115 in a haplotype network. The patterns of within-host haplotype clustering are consistent with the possibility of a clonal genetic structure and rapid within-host mutation after infection. Conclusion Avian malaria (P. relictum) and Avipoxvirus are the significant infectious diseases currently affecting the native Hawaiian avifauna. This study

  4. Genetic characterization of Hawaiian isolates of Plasmodium relictum reveals mixed-genotype infections.

    PubMed

    Jarvi, Susan I; Farias, Margaret E M; Atkinson, Carter T

    2008-06-25

    The relatively recent introduction of a highly efficient mosquito vector and an avian pathogen (Plasmodium relictum) to an isolated island ecosystem with naïve, highly susceptible avian hosts provides a unique opportunity to investigate evolution of virulence in a natural system. Mixed infections can significantly contribute to the uncertainty in host-pathogen dynamics with direct impacts on virulence. Toward further understanding of how host-parasite and parasite-parasite relationships may impact virulence, this study characterizes within-host diversity of malaria parasite populations based on genetic analysis of the trap (thrombospondin-related anonymous protein) gene in isolates originating from Hawaii, Maui and Kauai Islands. A total of 397 clones were produced by nested PCR amplification and cloning of a 1664 bp fragment of the trap gene from two malarial isolates, K1 (Kauai) and KV115 (Hawaii) that have been used for experimental studies, and from additional isolates from wild birds on Kauai, Maui and Hawaii Islands. Diversity of clones was evaluated initially by RFLP-based screening, followed by complete sequencing of 33 selected clones. RFLP analysis of trap revealed a minimum of 28 distinct RFLP haplotypes among the 397 clones from 18 birds. Multiple trap haplotypes were detected in every bird evaluated, with an average of 5.9 haplotypes per bird. Overall diversity did not differ between the experimental isolates, however, a greater number of unique haplotypes were detected in K1 than in KV115. We detected high levels of clonal diversity with clear delineation between isolates K1 and KV115 in a haplotype network. The patterns of within-host haplotype clustering are consistent with the possibility of a clonal genetic structure and rapid within-host mutation after infection. Avian malaria (P. relictum) and Avipoxvirus are the significant infectious diseases currently affecting the native Hawaiian avifauna. This study shows that clonal diversity of Hawaiian

  5. Experimental infection of the olive baboon (Paplio anubis) with Plasmodium knowlesi: severe disease accompanied by cerebral involvement.

    PubMed

    Ozwara, Hastings; Langermans, Jan A M; Maamun, Jenneby; Farah, Idle O; Yole, Dorcas S; Mwenda, Jason M; Weiler, Horst; Thomas, Alan W

    2003-08-01

    Experimental systems that model some of the complex interactions between parasite and host can be extremely valuable in identifying and developing new prophylactics and therapeutics against human diseases. Because primates have similar immune systems to humans, we have characterized a baboon model for understanding host response to Plasmodium knowlesi. Ten intact olive baboons (Papio anubis) of either sex were experimentally infected with P. knowlesi H strain erythrocytic parasites. The infection in these baboons was either acute or chronic. Animals with acute infection developed multiple system organ dysfunction and cerebral involvement. In chronically infected animals, only the spleen was moderately enlarged. The P. knowlesi parasitemia profile in baboons and rhesus monkeys was comparable. However, some clinical symptoms of the baboons and P. falciparum-infected humans were similar. These studies demonstrate for the first time that P. anubis is a suitable host for P. knowlesi for studying clinical symptoms and pathology.

  6. Evaluation of the ex vivo antimalarial activity of organotin (IV) ethylphenyldithiocarbamate on erythrocytes infected with Plasmodium berghei NK 65.

    PubMed

    Awang, Normah; Jumat, Hafizah; Ishak, Shafariatul Akmar; Kamaludin, Nurul Farahana

    2014-06-01

    Malaria is the most destructive and dangerous parasitic disease. The commonness of this disease is getting worse mainly due to the increasing resistance of Plasmodium falciparum against antimalarial drugs. Therefore, the search for new antimalarial drug is urgently needed. This study was carried out to evaluate the effects of dibutyltin (IV) ethylphenyldithiocarbamate (DBEP), diphenyltin (IV) ethylphenyldithiocarbamate (DPEP) and triphenyltin (IV) ethylphenyldithiocarbamate (TPEP) compounds as antimalarial agents. These compounds were evaluated against erythrocytes infected with Plasmodium berghei NK65 via ex vivo. Organotin (IV) ethylphenyldithiocarbamate, [R(n)Sn(C9H10NS2)(4-n)] with R = C4H9 and C6H5 for n = 2; R = C6H5 for n = 3 is chemically synthesised for its potential activities. pLDH assay was employed for determination of the concentration that inhibited 50% of the Plasmodium's activity (IC50) after 24 h treatment at concentration range of 10-0.0000001 mg mL(-1). Plasmodium berghei NK65 was cultured in vitro to determine the different morphology of trophozoite and schizont. Only DPEP and TPEP compounds have antimalarial activity towards P. berghei NK65 at IC50 0.094±0.011 and 0.892±0.088 mg mL(-1), respectively. The IC50 of DPEP and TPEP were lowest at 30% parasitemia with IC50 0.001±0.00009 and 0.0009±0.0001 mg mL(-1), respectively. In vitro culture showed that TPEP was effective towards P. berghei NK65 in trophozoite and schizont morphology with IC50 0.0001±0.00005 and 0.00009±0.00003 μg mL(-1), respectively. In conclusion, DPEP and TPEP have antimalarial effect on erythrocytes infected with P. berghei NK65 and have potential as antimalarial and schizonticidal agents.

  7. Monitoring of Plasmodium infection in humans and potential vectors of malaria in a newly emerged focus in southern Iran.

    PubMed

    Kalantari, Mohsen; Soltani, Zahra; Ebrahimi, Mostafa; Yousefi, Masoud; Amin, Masoumeh; Shafiei, Ayda; Azizi, Kourosh

    2017-02-01

    Despite control programs, which aim to eliminate malaria from Iran by 2025, transmission of malaria has not been removed from the country. This study aimed to monitor malaria from asymptomatic parasitaemia and clinical cases from about one year of active case surveillance and potential vectors of malaria in the newly emerged focus of Mamasani and Rostam, southern Iran during 2014-2015. Samples were collected and their DNAs were extracted for Polymerase Chain Reaction (PCR) assay using specific primers for detection of Plasmodium species. The Annual Parasite Incidence rate (API) was three cases per 1,000 population from 2,000 individuals in three villages. Parasites species were detected in 9 out of the 4,000 blood smear samples among which, 6 cases were indigenous and had no history of travels to endemic areas of malaria. Also, the prevalence rate of asymptomatic parasites was about 0.3%. Overall, 1073 Anopheles spp. were caught from 9 villages. Totally, 512 female samples were checked by PCR, which indicated that none of them was infected with Plasmodium. Despite new malaria local transmission in humans in Mamasani and Rostam districts, no infection with Plasmodium was observed in Anopheles species. Because of neighboring of the studied area to the re-emerged focus in Fars province (Kazerun) and important endemic foci of malaria in other southern provinces, such as Hormozgan and Kerman, monitoring of the vectors and reservoir hosts of Plasmodium species would be unavoidable. Application of molecular methods, such as PCR, can simplify access to the highest level of accuracy in malaria researches.

  8. Global Mass Spectrometry Based Metabolomics Profiling of Erythrocytes Infected with Plasmodium falciparum

    PubMed Central

    Sana, Theodore R.; Gordon, D. Benjamin; Fischer, Steven M.; Tichy, Shane E.; Kitagawa, Norton; Lai, Cindy; Gosnell, William L.; Chang, Sandra P.

    2013-01-01

    Malaria is a global infectious disease that threatens the lives of millions of people. Transcriptomics, proteomics and functional genomics studies, as well as sequencing of the Plasmodium falciparum and Homo sapiens genomes, have shed new light on this host-parasite relationship. Recent advances in accurate mass measurement mass spectrometry, sophisticated data analysis software, and availability of biological pathway databases, have converged to facilitate our global, untargeted biochemical profiling study of in vitro P. falciparum-infected (IRBC) and uninfected (NRBC) erythrocytes. In order to expand the number of detectable metabolites, several key analytical steps in our workflows were optimized. Untargeted and targeted data mining resulted in detection of over one thousand features or chemical entities. Untargeted features were annotated via matching to the METLIN metabolite database. For targeted data mining, we queried the data using a compound database derived from a metabolic reconstruction of the P. falciparum genome. In total, over one hundred and fifty differential annotated metabolites were observed. To corroborate the representation of known biochemical pathways from our data, an inferential pathway analysis strategy was used to map annotated metabolites onto the BioCyc pathway collection. This hypothesis-generating approach resulted in over-representation of many metabolites onto several IRBC pathways, most prominently glycolysis. In addition, components of the “branched” TCA cycle, partial urea cycle, and nucleotide, amino acid, chorismate, sphingolipid and fatty acid metabolism were found to be altered in IRBCs. Interestingly, we detected and confirmed elevated levels for cyclic ADP ribose and phosphoribosyl AMP in IRBCs, a novel observation. These metabolites may play a role in regulating the release of intracellular Ca2+ during P. falciparum infection. Our results support a strategy of global metabolite profiling by untargeted data

  9. Parasite impairment by targeting Plasmodium-infected RBCs using glyceryl-dilaurate nanostructured lipid carriers.

    PubMed

    Jain, Soniya A; Basu, Himanish; Prabhu, Priyanka S; Soni, Umangi; Joshi, Medha D; Mathur, Deepak; Patravale, Vandana B; Pathak, Sulabha; Sharma, Shobhona

    2014-08-01

    Antimalarial therapy is a major contributor to declining malaria morbidity and mortality. However, the high toxicity and low bioavailability of current antimalarials and emerging drug resistance necessitates drug-delivery research. We have previously developed glyceryl-dilaurate nanolipid carriers (GDL-NLCs) for antimalarial drug delivery. Here, we show evidence that GDL-NLCs themselves selectively target Plasmodium-infected red blood cells (iRBCs), and cause severe parasite impairment. The glyceryl-dilaurate lipid-moiety was important in the targeting. GDL-NLCs localized to the parasite mitochondrion and uptake led to mitochondrial-membrane polarization and Ca(2+) ion accumulation, ROS release, and stage-specific iRBC lysis. GDL-NLC treatment also resulted in externalization of iRBC-membrane phosphatidylserine and enhanced iRBC clearance by macrophages. GDL-NLC uptake disrupted the parasite-induced tubulovesicular network, which is vital for nutrient import by the parasite. Laser optical trap studies revealed that GDL-NLCs also restored iRBC flexibility. Such restoration of iRBC flexibility may help mitigate the vasculature clogging that can lead to cerebral malaria. We demonstrate the suitability of GDL-NLCs for intravenous delivery of antimalarial combinations artemether-clindamycin and artemether-lumefantrine in the murine model. Complete parasite clearance was achieved at 5-20% of the therapeutic dose of these combinations. Thus, this nanostructured lipid formulation can solubilize lipophilic drugs, selectively target and impair the parasite-infected red cell, and therefore constitutes a potent delivery vehicle for antimalarials.

  10. Optimized high gradient magnetic separation for isolation of Plasmodium-infected red blood cells

    PubMed Central

    2010-01-01

    Background Highly purified infected red blood cells (irbc), or highly synchronized parasite cultures, are regularly required in malaria research. Conventional isolation and synchronization rely on density and osmotic fragility of irbc, respectively. High gradient magnetic separation (HGMS) offers an alternative based on intrinsic magnetic properties of irbc, avoiding exposure to chemicals and osmotic stress. Successful HGMS concentration in malaria research was previously reported using polymer coated columns, while HGMS depletion has not been described yet. This study presents a new approach to both HGMS concentration and depletion in malaria research, rendering polymer coating unnecessary. Methods A dipole magnet generating a strong homogenous field was custom assembled. Polypropylene syringes were fitted with one-way stopcocks and filled with stainless steel wool. Rbc from Plasmodium falciparum cultures were resuspended in density and viscosity optimized HGMS buffers and HGMS processed. Purification and depletion results were analysed by flow cytometer and light microscopy. Viability was evaluated by calculating the infection rate after re-culturing of isolates. Results In HGMS concentration, purity of irbc isolates from asynchronous cultures consistently ranged from 94.8% to 98.4% (mean 95.7%). With further optimization, over 90% of isolated irbc contained segmented schizonts. Processing time was less than 45 min. Reinfection rates ranged from 21.0% to 56.4%. In HGMS depletion, results were comparable to treatment with sorbitol, as demonstrated by essentially identical development of cultures. Conclusion The novel HGMS concentration procedure achieves high purities of segmented stage irbc from standard asynchronous cultures, and is the first HGMS depletion alternative to sorbitol lysis. It represents a simple and highly efficient alternative to conventional irbc concentration and synchronization methods. PMID:20122252

  11. Optimized high gradient magnetic separation for isolation of Plasmodium-infected red blood cells.

    PubMed

    Bhakdi, Sebastian C; Ottinger, Annette; Somsri, Sangdao; Sratongno, Panudda; Pannadaporn, Peeranad; Chimma, Pattamawan; Malasit, Prida; Pattanapanyasat, Kovit; Neumann, Hartmut P H

    2010-02-02

    Highly purified infected red blood cells (irbc), or highly synchronized parasite cultures, are regularly required in malaria research. Conventional isolation and synchronization rely on density and osmotic fragility of irbc, respectively. High gradient magnetic separation (HGMS) offers an alternative based on intrinsic magnetic properties of irbc, avoiding exposure to chemicals and osmotic stress. Successful HGMS concentration in malaria research was previously reported using polymer coated columns, while HGMS depletion has not been described yet. This study presents a new approach to both HGMS concentration and depletion in malaria research, rendering polymer coating unnecessary. A dipole magnet generating a strong homogenous field was custom assembled. Polypropylene syringes were fitted with one-way stopcocks and filled with stainless steel wool. Rbc from Plasmodium falciparum cultures were resuspended in density and viscosity optimized HGMS buffers and HGMS processed. Purification and depletion results were analysed by flow cytometer and light microscopy. Viability was evaluated by calculating the infection rate after re-culturing of isolates. In HGMS concentration, purity of irbc isolates from asynchronous cultures consistently ranged from 94.8% to 98.4% (mean 95.7%). With further optimization, over 90% of isolated irbc contained segmented schizonts. Processing time was less than 45 min. Reinfection rates ranged from 21.0% to 56.4%. In HGMS depletion, results were comparable to treatment with sorbitol, as demonstrated by essentially identical development of cultures. The novel HGMS concentration procedure achieves high purities of segmented stage irbc from standard asynchronous cultures, and is the first HGMS depletion alternative to sorbitol lysis. It represents a simple and highly efficient alternative to conventional irbc concentration and synchronization methods.

  12. Immunization with the MAEBL M2 Domain Protects against Lethal Plasmodium yoelii Infection

    PubMed Central

    Leite, Juliana A.; Bargieri, Daniel Y.; Carvalho, Bruna O.; Albrecht, Letusa; Lopes, Stefanie C. P.; Kayano, Ana Carolina A. V.; Farias, Alessandro S.; Chia, Wan Ni; Claser, Carla; Malleret, Benoit; Russell, Bruce; Castiñeiras, Catarina; Santos, Leonilda M. B.; Brocchi, Marcelo; Wunderlich, Gerhard; Soares, Irene S.; Rodrigues, Mauricio M.; Rénia, Laurent

    2015-01-01

    Malaria remains a world-threatening disease largely because of the lack of a long-lasting and fully effective vaccine. MAEBL is a type 1 transmembrane molecule with a chimeric cysteine-rich ectodomain homologous to regions of the Duffy binding-like erythrocyte binding protein and apical membrane antigen 1 (AMA1) antigens. Although MAEBL does not appear to be essential for the survival of blood-stage forms, ectodomains M1 and M2, homologous to AMA1, seem to be involved in parasite attachment to erythrocytes, especially M2. MAEBL is necessary for sporozoite infection of mosquito salivary glands and is expressed in liver stages. Here, the Plasmodium yoelii MAEBL-M2 domain was expressed in a prokaryotic vector. C57BL/6J mice were immunized with doses of P. yoelii recombinant protein rPyM2-MAEBL. High levels of antibodies, with balanced IgG1 and IgG2c subclasses, were achieved. rPyM2-MAEBL antisera were capable of recognizing the native antigen. Anti-MAEBL antibodies recognized different MAEBL fragments expressed in CHO cells, showing stronger IgM and IgG responses to the M2 domain and repeat region, respectively. After a challenge with P. yoelii YM (lethal strain)-infected erythrocytes (IE), up to 90% of the immunized animals survived and a reduction of parasitemia was observed. Moreover, splenocytes harvested from immunized animals proliferated in a dose-dependent manner in the presence of rPyM2-MAEBL. Protection was highly dependent on CD4+, but not CD8+, T cells toward Th1. rPyM2-MAEBL antisera were also able to significantly inhibit parasite development, as observed in ex vivo P. yoelii erythrocyte invasion assays. Collectively, these findings support the use of MAEBL as a vaccine candidate and open perspectives to understand the mechanisms involved in protection. PMID:26169268

  13. Primary Infection of C57BL/6 Mice with Plasmodium yoelii Induces a Heterogeneous Response of NKT Cells▿

    PubMed Central

    Soulard, Valérie; Roland, Jacques; Sellier, Christèle; Gruner, Anne Charlotte; Leite-de-Moraes, Maria; Franetich, Jean-François; Rénia, Laurent; Cazenave, Pierre-André; Pied, Sylviane

    2007-01-01

    NKT cells are a population of innate-like lymphocytes that display effector functions and immunoregulatory properties. We characterized the NKT cell response induced in C57BL/6 mice during a primary infection with Plasmodium yoelii sporozoites. We observed a heterogeneous NKT cell response that differed between liver and spleen. Hepatic NKT cells found in infected livers consisted mainly of CD1d-dependent CD4+ and double-negative (DN) NKT cells, whereas CD1d-independent NKT cells exhibiting a TCRhigh CD4high phenotype were prominent among splenic NKT cells during the infection. Hepatic and splenic NKT cells isolated from infected mice were activated and secreted mainly gamma interferon and tumor necrosis factor alpha in response to stimulation. Finally, P. yoelii-activated hepatic DN NKT cells inhibited the parasite's liver stage in a CD1d-dependent manner in vitro. However, experiments using B6.CD1d-deficient mice showed that CD1d and CD1d-restricted NKT cells are not necessary to control the parasite's development in vivo during neither the preerythrocytic stage nor the erythrocytic stage. Thus, our results show that a primary P. yoelii infection induces a heterogeneous and organ-specific response of NKT cells and that CD1d-dependent NKT cells play a minor role in the control of the development of Plasmodium in vivo in our model. PMID:17307938

  14. Increased detection of Plasmodium knowlesi in Sandakan division, Sabah as revealed by PlasmoNex™

    PubMed Central

    2013-01-01

    Background Plasmodium knowlesi is a simian malaria parasite that is widespread in humans in Malaysian Borneo. However, little is known about the incidence and distribution of this parasite in the Sandakan division, Malaysian Borneo. Therefore, the aim of the present epidemiological study was to investigate the incidence and distribution of P. knowlesi as well as other Plasmodium species in this division based on a most recent developed hexaplex PCR system (PlasmoNex™). Methods A total of 189 whole blood samples were collected from Telupid Health Clinic, Sabah, Malaysia, from 2008 to 2011. All patients who participated in the study were microscopically malaria positive before recruitment. Complete demographic details and haematological profiles were obtained from 85 patients (13 females and 72 males). Identification of Plasmodium species was conducted using PlasmoNex™ targeting the 18S ssu rRNA gene. Results A total of 178 samples were positive for Plasmodium species by using PlasmoNex™. Plasmodium falciparum was identified in 68 samples (38.2%) followed by 64 cases (36.0%) of Plasmodium vivax, 42 (23.6%) cases of P. knowlesi, two (1.1%) cases of Plasmodium malariae and two (1.1%) mixed-species infections (i e, P. vivax/P. falciparum). Thirty-five PlasmoNex™ positive P. knowlesi samples were misdiagnosed as P. malariae by microscopy. Plasmodium knowlesi was detected in all four districts of Sandakan division with the highest incidence in the Kinabatangan district. Thrombocytopaenia and anaemia showed to be the most frequent malaria-associated haematological complications in this study. Conclusions The discovery of P. knowlesi in Sandakan division showed that prospective studies on the epidemiological risk factors and transmission dynamics of P. knowlesi in these areas are crucial in order to develop strategies for effective malaria control. The availability of advanced diagnostic tool PlasmoNex™ enhanced the accuracy and accelerated the speed in the

  15. Anti-Inflammatory Cytokines Predominate in Acute Human Plasmodium knowlesi Infections

    PubMed Central

    Cox-Singh, Janet; Singh, Balbir; Daneshvar, Cyrus; Planche, Timothy; Parker-Williams, John; Krishna, Sanjeev

    2011-01-01

    Plasmodium knowlesi has entered the human population of Southeast Asia. Naturally acquired knowlesi malaria is newly described with relatively little available data, including data on the host response to infection. Therefore pre-treatment cytokine and chemokine profiles were determined for 94 P. knowlesi, and for comparison, 20, P. vivax and 22 P. falciparum, patients recruited in Malaysian Borneo. Nine, five and one patient with P. knowlesi, P. falciparum and P. vivax respectively had complicated malaria as defined by World Health Organisation. Patients with uncomplicated P. knowlesi had lower levels of the pro-inflammatory cytokines IL-8 and TNFα than those with complicated disease (both p<0.05, Dunn's post test, DPT). The anti-inflammatory cytokines IL-1ra and IL-10 were detected in all patients in the study. IL-1ra, the most abundant cytokine measured, correlated with parasitaemia in P. knowlesi (rs = 0.47, p =  <0.0001), P. vivax (rs = 0.61, p = 0.0042) and P. falciparum (rs = 0.57,p = 0.0054) malaria. IL-10 correlated with parasitaemia in both P. knowlesi (rs = 0.54, p =  <0.0001) and P. vivax (rs = 0.78, p =  <0.0001) infections. There were between group differences in soluble markers of macrophage activation (MIP-1β and MCP-1). P. knowlesi patients had significantly lower levels of MIP-1β than P. falciparum (DPT, p =  <0.01). Uncomplicated P. knowlesi patients had significantly lower levels of MCP-1 than uncomplicated P. falciparum patients (DPT, p =  <0.001). There was no significant difference between complicated and uncomplicated P. knowlesi infections. MCP-1, MIP-1β, IL-8 and TNFα increased in complicated P. knowlesi but decreased in complicated P. falciparum infections. Descriptions of human knowlesi malaria provide a comparative means to discover mediators of pathophysiology in severe P. knowlesi as well as P. falciparum malaria. Crucially, P. knowlesi may be the disease and experimental primate

  16. FRET Imaging of Hemoglobin Concentration in Plasmodium falciparum-Infected Red Cells

    PubMed Central

    Esposito, Alessandro; Tiffert, Teresa; Mauritz, Jakob M. A.; Schlachter, Simon; Bannister, Lawrence H.; Kaminski, Clemens F.; Lew, Virgilio L.

    2008-01-01

    Background During its intraerythrocytic asexual reproduction cycle Plasmodium falciparum consumes up to 80% of the host cell hemoglobin, in large excess over its metabolic needs. A model of the homeostasis of falciparum-infected red blood cells suggested an explanation based on the need to reduce the colloid-osmotic pressure within the host cell to prevent its premature lysis. Critical for this hypothesis was that the hemoglobin concentration within the host cell be progressively reduced from the trophozoite stage onwards. Methodology/Principal Findings The experiments reported here were designed to test this hypothesis by direct measurements of the hemoglobin concentration in live, infected red cells. We developed a novel, non-invasive method to quantify the hemoglobin concentration in single cells, based on Förster resonance energy transfer between hemoglobin molecules and the fluorophore calcein. Fluorescence lifetime imaging allowed the quantitative mapping of the hemoglobin concentration within the cells. The average fluorescence lifetimes of uninfected cohorts was 270±30 ps (mean±SD; N = 45). In the cytoplasm of infected cells the fluorescence lifetime of calcein ranged from 290±20 ps for cells with ring stage parasites to 590±13 ps and 1050±60 ps for cells with young trophozoites and late stage trophozoite/ early schizonts, respectively. This was equivalent to reductions in hemoglobin concentration spanning the range from 7.3 to 2.3 mM, in line with the model predictions. An unexpected ancillary finding was the existence of a microdomain under the host cell membrane with reduced calcein quenching by hemoglobin in cells with mature trophozoite stage parasites. Conclusions/Significance The results support the predictions of the colloid-osmotic hypothesis and provide a better understanding of the homeostasis of malaria-infected red cells. In addition, they revealed the existence of a distinct peripheral microdomain in the host cell with limited access

  17. Plasmodium knowlesi from archival blood films: Further evidence that human infections are widely distributed and not newly emergent in Malaysian Borneo

    PubMed Central

    Lee, Kim-Sung; Cox-Singh, Janet; Brooke, George; Matusop, Asmad; Singh, Balbir

    2009-01-01

    Human infections with Plasmodium knowlesi have been misdiagnosed by microscopy as Plasmodium malariae due to their morphological similarities. Although microscopy-identified P. malariae cases have been reported in the state of Sarawak (Malaysian Borno) as early as 1952, recent epidemiological studies suggest the absence of indigenous P. malariae infections. The present study aimed to determine the past incidence and distribution of P. knowlesi infections in the state of Sarawak based on archival blood films from patients diagnosed by microscopy as having P. malariae infections. Nested PCR assays were used to identify Plasmodium species in DNA extracted from 47 thick blood films collected in 1996 from patients in seven different divisions throughout the state of Sarawak. Plasmodium knowlesi DNA was detected in 35 (97.2%) of 36 blood films that were positive for Plasmodium DNA, with patients originating from all seven divisions. Only one sample was positive for P. malariae DNA. This study provides further evidence of the widespread distribution of human infections with P. knowlesi in Sarawak and its past occurrence. Taken together with data from previous studies, our findings suggest that P. knowlesi malaria is not a newly emergent disease in humans. PMID:19358848

  18. Antimalarial and antioxidant activities of methanolic extract of Nigella sativa seeds (black cumin) in mice infected with Plasmodium yoelli nigeriensis.

    PubMed

    Okeola, Valeelat O; Adaramoye, Oluwatosin A; Nneji, Chiaka M; Falade, Catherine O; Farombi, E Olatunde; Ademowo, Olusegun G

    2011-06-01

    The antimalarial and antioxidant activities of methanolic extract of Nigella sativa seeds (MENS) were investigated against established malaria infection in vivo using Swiss albino mice. The antimalarial activity of the extract against Plasmodium yoelli nigeriensis (P. yoelli) was assessed using the Rane test procedure. Chloroquine (CQ)-treated group served as positive control. The extract, at a dose of 1.25 g/kg body weight significantly (p<0.05) suppressed P. yoelli infection in the mice by 94%, while CQ, the reference drug, produced 86% suppression when compared to the untreated group after the fifth day of treatment. P. yoelli infection caused a significant (p<0.05) increase in the levels of red cell and hepatic malondialdehyde (MDA), an index of lipid peroxidation (LPO) in the mice. Serum and hepatic LPO levels were increased by 71% and 113%, respectively, in the untreated infected mice. Furthermore, P. yoelli infection caused a significant (p<0.05) decrease in the activities of superoxide dismutase, catalase, glutathione-S-transferase and the level of reduced glutathione in tissues of the mice. Treatment with MENS significantly (p<0.05) attenuated the serum and hepatic MDA levels in P. yoelli-infected mice. In addition, MENS restored the activities of red cell antioxidant enzymes in the infected mice to near normal. Moreover, MENS was found to be more effective than CQ in parasite clearance and, in the restoration of altered biochemical indices by P. yoelli infection. These results suggest that N. sativa seeds have strong antioxidant property and, may be a good phytotherapeutic agent against Plasmodium infection in malaria.

  19. Co-infection with Plasmodium berghei and Trypanosoma brucei increases severity of malaria and trypanosomiasis in mice.

    PubMed

    Ademola, Isaiah Oluwafemi; Odeniran, Paul Olalekan

    2016-07-01

    Individuals in natural populations may be infected with multiple different parasites at a time. These parasites may interact with each other or act independently in the host, and this may result to varying outcomes on host health and survival. This study therefore aimed at investigating the health impact of co-infection of mice with Plasmodium berghei and Trypanosoma brucei. Forty Swiss albino mice (14-17g) were divided into four groups of ten. Mice in groups A and B received 10(6)P. berghei and groups B and C 10(5)T. brucei, while group D were uninfected. The co-infected mice had higher P. berghei and T. brucei parasitaemia, compared with the mono-infected mice. The co-infected mice had significantly (p<0.05) lower survival rate compared with the mono-infected mice. Co-infection of mice with P. berghei and T. brucei resulted in rapid P. berghei and T. brucei development and increased parasitaemia. The leukocyte numbers significantly (p<0.05) reduced on days 12 and 15 post infection among P. berghei infected mice, in the presence or absence of T. brucei. Anaemia and hypoglycaemia was more severe in the co-infected mice. Therefore, co-infection of mice with P. berghei and T. brucei may increase pathologic impact to the host by increasing parasitaemia.

  20. Long-term live imaging reveals cytosolic immune responses of host hepatocytes against Plasmodium infection and parasite escape mechanisms

    PubMed Central

    Prado, Monica; Eickel, Nina; De Niz, Mariana; Heitmann, Anna; Agop-Nersesian, Carolina; Wacker, Rahel; Schmuckli-Maurer, Jacqueline; Caldelari, Reto; Janse, Chris J; Khan, Shahid M; May, Jürgen; Meyer, Christian G; Heussler, Volker T

    2015-01-01

    Plasmodium parasites are transmitted by Anopheles mosquitoes to the mammalian host and actively infect hepatocytes after passive transport in the bloodstream to the liver. In their target host hepatocyte, parasites reside within a parasitophorous vacuole (PV). In the present study it was shown that the parasitophorous vacuole membrane (PVM) can be targeted by autophagy marker proteins LC3, ubiquitin, and SQSTM1/p62 as well as by lysosomes in a process resembling selective autophagy. The dynamics of autophagy marker proteins in individual Plasmodium berghei-infected hepatocytes were followed by live imaging throughout the entire development of the parasite in the liver. Although the host cell very efficiently recognized the invading parasite in its vacuole, the majority of parasites survived this initial attack. Successful parasite development correlated with the gradual loss of all analyzed autophagy marker proteins and associated lysosomes from the PVM. However, other autophagic events like nonselective canonical autophagy in the host cell continued. This was indicated as LC3, although not labeling the PVM anymore, still localized to autophagosomes in the infected host cell. It appears that growing parasites even benefit from this form of nonselective host cell autophagy as an additional source of nutrients, as in host cells deficient for autophagy, parasite growth was retarded and could partly be rescued by the supply of additional amino acid in the medium. Importantly, mouse infections with P. berghei sporozoites confirmed LC3 dynamics, the positive effect of autophagy activation on parasite growth, and negative effects upon autophagy inhibition. PMID:26208778

  1. Long-term live imaging reveals cytosolic immune responses of host hepatocytes against Plasmodium infection and parasite escape mechanisms.

    PubMed

    Prado, Monica; Eickel, Nina; De Niz, Mariana; Heitmann, Anna; Agop-Nersesian, Carolina; Wacker, Rahel; Schmuckli-Maurer, Jacqueline; Caldelari, Reto; Janse, Chris J; Khan, Shahid M; May, Jürgen; Meyer, Christian G; Heussler, Volker T

    2015-01-01

    Plasmodium parasites are transmitted by Anopheles mosquitoes to the mammalian host and actively infect hepatocytes after passive transport in the bloodstream to the liver. In their target host hepatocyte, parasites reside within a parasitophorous vacuole (PV). In the present study it was shown that the parasitophorous vacuole membrane (PVM) can be targeted by autophagy marker proteins LC3, ubiquitin, and SQSTM1/p62 as well as by lysosomes in a process resembling selective autophagy. The dynamics of autophagy marker proteins in individual Plasmodium berghei-infected hepatocytes were followed by live imaging throughout the entire development of the parasite in the liver. Although the host cell very efficiently recognized the invading parasite in its vacuole, the majority of parasites survived this initial attack. Successful parasite development correlated with the gradual loss of all analyzed autophagy marker proteins and associated lysosomes from the PVM. However, other autophagic events like nonselective canonical autophagy in the host cell continued. This was indicated as LC3, although not labeling the PVM anymore, still localized to autophagosomes in the infected host cell. It appears that growing parasites even benefit from this form of nonselective host cell autophagy as an additional source of nutrients, as in host cells deficient for autophagy, parasite growth was retarded and could partly be rescued by the supply of additional amino acid in the medium. Importantly, mouse infections with P. berghei sporozoites confirmed LC3 dynamics, the positive effect of autophagy activation on parasite growth, and negative effects upon autophagy inhibition.

  2. Avian malaria (Plasmodium spp) in yellow-eyed penguins: investigating the cause of high seroprevalence but low observed infection.

    PubMed

    Sturrock, H J W; Tompkins, D M

    2007-08-01

    To investigate the cause of a high seroprevalence of antibodies to Plasmodium spp known to cause avian malaria, but extremely low levels of observed infection, in yellow-eyed penguins, Megadyptes antipodes. A polymerase chain reaction (PCR) test specific for malarial parasites was applied to DNA extracted from blood samples collected from 143 yellow-eyed penguins from an area where seroprevalence for malarial antibodies was known to be high but no parasites were observed in blood smears. None of the samples tested positive for malarial parasite DNA using the PCR test. Assuming a sensitivity of 90% for this test, this means that prevalence of infection was 95% likely to be <2.3% in this population during this sampling period. Serological studies of a population of adult yellow-eyed penguins indicated a high level of exposure to avian malaria parasites, but a correspondingly high level of infection was not observed and no evidence of malarial parasite DNA was found in the current study. Discrepancies between these findings and historical records of Plasmodium spp found in blood smears and post mortem may be explained either by inaccuracy of the serological test used, or by infection occurring in juveniles which is subsequently cleared in surviving adults.

  3. Pivotal and distinct role for Plasmodium actin capping protein alpha during blood infection of the malaria parasite

    PubMed Central

    Ganter, Markus; Rizopoulos, Zaira; Schüler, Herwig; Matuschewski, Kai

    2015-01-01

    Accurate regulation of microfilament dynamics is central to cell growth, motility and response to environmental stimuli. Stabilizing and depolymerizing proteins control the steady-state levels of filamentous (F-) actin. Capping protein (CP) binds to free barbed ends, thereby arresting microfilament growth and restraining elongation to remaining free barbed ends. In all CPs characterized to date, alpha and beta subunits form the active heterodimer. Here, we show in a eukaryotic parasitic cell that the two CP subunits can be functionally separated. Unlike the beta subunit, the CP alpha subunit of the apicomplexan parasite Plasmodium is refractory to targeted gene deletion during blood infection in the mammalian host. Combinatorial complementation of Plasmodium berghei CP genes with the orthologs from Plasmodium falciparum verified distinct activities of CP alpha and CP alpha/beta during parasite life cycle progression. Recombinant Plasmodium CP alpha could be produced in Escherichia coli in the absence of the beta subunit and the protein displayed F-actin capping activity. Thus, the functional separation of two CP subunits in a parasitic eukaryotic cell and the F-actin capping activity of CP alpha expand the repertoire of microfilament regulatory mechanisms assigned to CPs. PMID:25565321

  4. Pivotal and distinct role for Plasmodium actin capping protein alpha during blood infection of the malaria parasite.

    PubMed

    Ganter, Markus; Rizopoulos, Zaira; Schüler, Herwig; Matuschewski, Kai

    2015-04-01

    Accurate regulation of microfilament dynamics is central to cell growth, motility and response to environmental stimuli. Stabilizing and depolymerizing proteins control the steady-state levels of filamentous (F-) actin. Capping protein (CP) binds to free barbed ends, thereby arresting microfilament growth and restraining elongation to remaining free barbed ends. In all CPs characterized to date, alpha and beta subunits form the active heterodimer. Here, we show in a eukaryotic parasitic cell that the two CP subunits can be functionally separated. Unlike the beta subunit, the CP alpha subunit of the apicomplexan parasite Plasmodium is refractory to targeted gene deletion during blood infection in the mammalian host. Combinatorial complementation of Plasmodium berghei CP genes with the orthologs from Plasmodium falciparum verified distinct activities of CP alpha and CP alpha/beta during parasite life cycle progression. Recombinant Plasmodium CP alpha could be produced in Escherichia coli in the absence of the beta subunit and the protein displayed F-actin capping activity. Thus, the functional separation of two CP subunits in a parasitic eukaryotic cell and the F-actin capping activity of CP alpha expand the repertoire of microfilament regulatory mechanisms assigned to CPs.

  5. The dangers of accepting a single diagnosis: case report of concurrent Plasmodium knowlesi malaria and dengue infection.

    PubMed

    Chong, Soon Eu; Mohamad Zaini, Rhendra Hardy; Suraiya, Siti; Lee, Kok Tong; Lim, Jo Anne

    2017-01-03

    Dengue and malaria are two common, mosquito-borne infections, which may lead to mortality if not managed properly. Concurrent infections of dengue and malaria are rare due to the different habitats of its vectors and activities of different carrier mosquitoes. The first case reported was in 2005. Since then, several concurrent infections have been reported between the dengue virus (DENV) and the malaria protozoans, Plasmodium falciparum and Plasmodium vivax. Symptoms of each infection may be masked by a simultaneous second infection, resulting in late treatment and severe complications. Plasmodium knowlesi is also a common cause of malaria in Malaysia with one of the highest rates of mortality. This report is one of the earliest in literature of concomitant infection between DENV and P. knowlesi in which a delay in diagnosis had placed a patient in a life-threatening situation. A 59-year old man staying near the Belum-Temengor rainforest at the Malaysia-Thailand border was admitted with fever for 6 days, with respiratory distress. His non-structural protein 1 antigen and Anti-DENV Immunoglobulin M tests were positive. He was treated for severe dengue with compensated shock. Treating the dengue had so distracted the clinicians that a blood film for the malaria parasite was not done. Despite aggressive supportive treatment in the intensive care unit (ICU), the patient had unresolved acidosis as well as multi-organ failure involving respiratory, renal, liver, and haematological systems. It was due to the presentation of shivering in the ICU, that a blood film was done on the second day that revealed the presence of P. knowlesi with a parasite count of 520,000/μL. The patient was subsequently treated with artesunate-doxycycline and made a good recovery after nine days in ICU. This case contributes to the body of literature on co-infection between DENV and P. knowlesi and highlights the clinical consequences, which can be severe. Awareness should be raised among

  6. Effects of sevuparin on rosette formation and cytoadherence of Plasmodium falciparum infected erythrocytes

    PubMed Central

    Saiwaew, Somporn; Sritabal, Juntima; Piaraksa, Nattaporn; Keayarsa, Srisuda; Ruengweerayut, Ronnatrai; Utaisin, Chirapong; Sila, Patima; Niramis, Rangsan; Udomsangpetch, Rachanee; Charunwatthana, Prakaykaew; Pongponratn, Emsri; Pukrittayakamee, Sasithon; Leitgeb, Anna M.; Wahlgren, Mats; Lee, Sue J.; Day, Nicholas P. J.; White, Nicholas J.; Dondorp, Arjen M.; Chotivanich, Kesinee

    2017-01-01

    In severe falciparum malaria cytoadherence of parasitised red blood cells (PRBCs) to vascular endothelium (causing sequestration) and to uninfected red cells (causing rosette formation) contribute to microcirculatory flow obstruction in vital organs. Heparin can reverse the underlying ligand-receptor interactions, but may increase the bleeding risks. As a heparin-derived polysaccharide, sevuparin has been designed to retain anti-adhesive properties, while the antithrombin-binding domains have been eliminated, substantially diminishing its anticoagulant activity. Sevuparin has been evaluated recently in patients with uncomplicated falciparum malaria, and is currently investigated in a clinical trial for sickle cell disease. The effects of sevuparin on rosette formation and cytoadherence of Plasmodium falciparum isolates from Thailand were investigated. Trophozoite stages of P. falciparum-infected RBCs (Pf-iRBCs) were cultured from 49 patients with malaria. Pf-iRBCs were treated with sevuparin at 37°C and assessed in rosetting and in cytoadhesion assays with human dermal microvascular endothelial cells (HDMECs) under static and flow conditions. The proportion of Pf-iRBCs forming rosettes ranged from 6.5% to 26.0% (median = 12.2%). Rosetting was dose dependently disrupted by sevuparin (50% disruption by 250 μg/mL). Overall 57% of P. falciparum isolates bound to HDMECs under static conditions; median (interquartile range) Pf-iRBC binding was 8.5 (3.0–38.0) Pf-iRBCs/1000 HDMECs. Sevuparin in concentrations ≥ 100 μg/mL inhibited cytoadherence. Sevuparin disrupts P. falciparum rosette formation in a dose dependent manner and inhibits cytoadherence to endothelial cells. The data support assessment of sevuparin as an adjunctive treatment to the standard therapy in severe falciparum malaria. PMID:28249043

  7. Effects of sevuparin on rosette formation and cytoadherence of Plasmodium falciparum infected erythrocytes.

    PubMed

    Saiwaew, Somporn; Sritabal, Juntima; Piaraksa, Nattaporn; Keayarsa, Srisuda; Ruengweerayut, Ronnatrai; Utaisin, Chirapong; Sila, Patima; Niramis, Rangsan; Udomsangpetch, Rachanee; Charunwatthana, Prakaykaew; Pongponratn, Emsri; Pukrittayakamee, Sasithon; Leitgeb, Anna M; Wahlgren, Mats; Lee, Sue J; Day, Nicholas P J; White, Nicholas J; Dondorp, Arjen M; Chotivanich, Kesinee

    2017-01-01

    In severe falciparum malaria cytoadherence of parasitised red blood cells (PRBCs) to vascular endothelium (causing sequestration) and to uninfected red cells (causing rosette formation) contribute to microcirculatory flow obstruction in vital organs. Heparin can reverse the underlying ligand-receptor interactions, but may increase the bleeding risks. As a heparin-derived polysaccharide, sevuparin has been designed to retain anti-adhesive properties, while the antithrombin-binding domains have been eliminated, substantially diminishing its anticoagulant activity. Sevuparin has been evaluated recently in patients with uncomplicated falciparum malaria, and is currently investigated in a clinical trial for sickle cell disease. The effects of sevuparin on rosette formation and cytoadherence of Plasmodium falciparum isolates from Thailand were investigated. Trophozoite stages of P. falciparum-infected RBCs (Pf-iRBCs) were cultured from 49 patients with malaria. Pf-iRBCs were treated with sevuparin at 37°C and assessed in rosetting and in cytoadhesion assays with human dermal microvascular endothelial cells (HDMECs) under static and flow conditions. The proportion of Pf-iRBCs forming rosettes ranged from 6.5% to 26.0% (median = 12.2%). Rosetting was dose dependently disrupted by sevuparin (50% disruption by 250 μg/mL). Overall 57% of P. falciparum isolates bound to HDMECs under static conditions; median (interquartile range) Pf-iRBC binding was 8.5 (3.0-38.0) Pf-iRBCs/1000 HDMECs. Sevuparin in concentrations ≥ 100 μg/mL inhibited cytoadherence. Sevuparin disrupts P. falciparum rosette formation in a dose dependent manner and inhibits cytoadherence to endothelial cells. The data support assessment of sevuparin as an adjunctive treatment to the standard therapy in severe falciparum malaria.

  8. Cytochrome b gene quantitative PCR for diagnosing Plasmodium falciparum infection in travelers.

    PubMed

    Farrugia, Cécile; Cabaret, Odile; Botterel, Françoise; Bories, Christian; Foulet, Françoise; Costa, Jean-Marc; Bretagne, Stéphane

    2011-06-01

    A cytochrome b (cytb) gene quantitative PCR (qPCR) assay was developed to diagnose malaria in travelers. First, manual and automated DNA extractions were compared and automated DNA extraction of 400 μl of blood was found to be more efficient. Sensitivity was estimated using the WHO international standard for Plasmodium falciparum DNA and compared to that of a previously published qPCR targeting the 18S rRNA coding gene (18S qPCR). The limit of detection of the cytb qPCR assay was 20 DNA copies (i.e., 1 parasite equivalent) per 400 μl of extracted whole blood and was comparable for the two qPCR assays. Both qPCR assays were used on blood samples from 265 consecutive patients seen for suspicion of malaria. There were no microscopy-positive and qPCR-negative samples. Positive cytb qPCR results were observed for 51 samples, and all but 1 were also 18S qPCR positive. Eight (16%) of these 51 samples were negative by microscopic examination. The 8 cytb qPCR-positive and microscopy-negative samples were from African patients, 3 of whom had received antimalarial drugs. Three non-P. falciparum infections were correctly identified using an additional qPCR assay. The absence of PCR inhibitors was tested for by the use of an internal control of mouse DNA to allow reliable quantification of circulating DNA. The high analytical sensitivity of both qPCR assays combined with automated DNA extraction supports its use as a laboratory tool for diagnosis and parasitemia determination in emergencies. Whether to treat qPCR-positive and microscopy-negative patients remains to be determined.

  9. High-resolution X-ray imaging of Plasmodium falciparum-infected red blood cells.

    PubMed

    Williams, Garth J; Hanssen, Eric; Peele, Andrew G; Pfeifer, Mark A; Clark, Jesse; Abbey, Brian; Cadenazzi, Guido; de Jonge, Martin D; Vogt, Stefan; Tilley, Leann; Nugent, Keith A

    2008-10-01

    Methods for imaging cellular architecture and ultimately macromolecular complexes and individual proteins, within a cellular environment, are an important goal for cell and molecular biology. Coherent diffractive imaging (CDI) is a method of lensless imaging that can be applied to any individual finite object. A diffraction pattern from a single biological structure is recorded and an iterative Fourier transform between real space and reciprocal space is used to reconstruct information about the architecture of the sample to high resolution. As a test system for cellular imaging, we have applied CDI to an important human pathogen, the malaria parasite, Plasmodium falciparum. We have employed a novel CDI approach, known as Fresnel CDI, which uses illumination with a curved incident wavefront, to image red blood cells infected with malaria parasites. We have examined the intrinsic X-ray absorption contrast of these cells and compared them with cells contrasted with heavy metal stains or immunogold labeling. We compare CDI images with data obtained from the same cells using scanning electron microscopy, light microscopy, and scanning X-ray fluorescence microscopy. We show that CDI can offer new information both within and at the surface of complex biological specimens at a spatial resolution of better than 40 nm. and we demonstrate an imaging modality that conveniently combines scanning X-ray fluorescence microscopy with CDI. The data provide independent confirmation of the validity of the coherent diffractive image and demonstrate that CDI offers the potential to become an important and reliable new high-resolution imaging modality for cell biology. CDI can detect features at high resolution within unsectioned cells.

  10. Neither the HIV Protease Inhibitor Lopinavir-Ritonavir nor the Antimicrobial Trimethoprim-Sulfamethoxazole Prevent Malaria Relapse in Plasmodium cynomolgi-Infected Non-Human Primates

    PubMed Central

    Hobbs, Charlotte V.; Dixit, Saurabh; Penzak, Scott R.; Sahu, Tejram; Orr-Gonzalez, Sachy; Lambert, Lynn; Zeleski, Katie; Chen, Jingyang; Neal, Jillian; Borkowsky, William; Wu, Yimin; Duffy, Patrick E.

    2014-01-01

    Plasmodium vivax malaria causes significant morbidity and mortality worldwide, and only one drug is in clinical use that can kill the hypnozoites that cause P. vivax relapses. HIV and P. vivax malaria geographically overlap in many areas of the world, including South America and Asia. Despite the increasing body of knowledge regarding HIV protease inhibitors (HIV PIs) on P. falciparum malaria, there are no data regarding the effects of these treatments on P. vivax's hypnozoite form and clinical relapses of malaria. We have previously shown that the HIV protease inhibitor lopinavir-ritonavir (LPV-RTV) and the antibiotic trimethoprim sulfamethoxazole (TMP-SMX) inhibit Plasmodium actively dividing liver stages in rodent malarias and in vitro in P. falciparum, but effect against Plasmodium dormant hypnozoite forms remains untested. Separately, although other antifolates have been tested against hypnozoites, the antibiotic trimethoprim sulfamethoxazole, commonly used in HIV infection and exposure management, has not been evaluated for hypnozoite-killing activity. Since Plasmodium cynomolgi is an established animal model for the study of liver stages of malaria as a surrogate for P. vivax infection, we investigated the antimalarial activity of these drugs on Plasmodium cynomolgi relapsing malaria in rhesus macaques. Herein, we demonstrate that neither TMP-SMX nor LPV-RTV kills hypnozoite parasite liver stage forms at the doses tested. Because HIV and malaria geographically overlap, and more patients are being managed for HIV infection and exposure, understanding HIV drug impact on malaria infection is important. PMID:25541998

  11. Spatial variation of Anopheles-transmitted Wuchereria bancrofti and Plasmodium falciparum infection densities in Papua New Guinea

    PubMed Central

    Alexander, Neal D; Moyeed, Rana A; Hyun, Phil J; Dimber, Zachary B; Bockarie, Moses J; Stander, Julian; Grenfell, Bryan T; Kazura, James W; Alpers, Michael P

    2003-01-01

    The spatial variation of Wuchereria bancrofti and Plasmodium falciparum infection densities was measured in a rural area of Papua New Guinea where they share anopheline vectors. The spatial correlation of W. bancrofti was found to reduce by half over an estimated distance of 1.7 km, much smaller than the 50 km grid used by the World Health Organization rapid mapping method. For P. falciparum, negligible spatial correlation was found. After mass treatment with anti-filarial drugs, there was negligible correlation between the changes in the densities of the two parasites. PMID:14525619

  12. Warm autoimmune hemolytic anemia secondary to Plasmodium ovale infection: a case report and review of the literature.

    PubMed

    Johnson, Adam S; Delisca, Gadini; Booth, Garrett S

    2013-12-01

    A three year old male from the Democratic Republic of the Congo was admitted to Monroe Carell Jr. Children's Hospital at Vanderbilt with a 10-day history of fever, emesis, and diarrhea. Examination demonstrated scleral icterus, splenomegaly, and anemia. By peripheral blood smear, the patient was diagnosed with Plasmodium ovale. Immunohematology demonstrated a positive direct antiglobulin test (DAT) for IgG and C3d with pan-agglutination on eluate. These findings, in combination with hemolytic labs, signified presence of an autoimmune hemolytic anemia (AIHA). We believe this to be the first reported case of P. ovale infection-mediated AIHA.

  13. Misclassification of Plasmodium infections by conventional microscopy and the impact of remedial training on the proficiency of laboratory technicians in species identification.

    PubMed

    Obare, Peter; Ogutu, Bernhards; Adams, Mohammed; Odera, James Sande; Lilley, Ken; Dosoo, David; Adhiambo, Christine; Owusu-Agyei, Seth; Binka, Fred; Wanja, Elizabeth; Johnson, Jacob

    2013-03-27

    Malaria diagnosis is largely dependent on the demonstration of parasites in stained blood films by conventional microscopy. Accurate identification of the infecting Plasmodium species relies on detailed examination of parasite morphological characteristics, such as size, shape, pigment granules, besides the size and shape of the parasitized red blood cells and presence of cell inclusions. This work explores misclassifications of four Plasmodium species by conventional microscopy relative to the proficiency of microscopists and morphological characteristics of the parasites on Giemsa-stained blood films. Ten-day malaria microscopy remedial courses on parasite detection, species identification and parasite counting were conducted for public health and research laboratory personnel. Proficiency in species identification was assessed at the start (pre) and the end (post) of each course using known blood films of Plasmodium falciparum, Plasmodium malariae, Plasmodium ovale and Plasmodium vivax infections with densities ranging from 1,000 to 30,000 parasites/μL. Outcomes were categorized as false negative, positive without speciation, P. falciparum, P. malariae, P. ovale, P. vivax and mixed infections. Reported findings are based on 1,878 P. falciparum, 483 P. malariae, 581 P. ovale and 438 P. vivax cumulative results collated from 2008 to 2010 remedial courses. Pre-training false negative and positive misclassifications without speciation were significantly lower on P. falciparum infections compared to non-falciparum infections (p < 0.0001). Post-training misclassifications decreased significantly compared to pre- training misclassifications which in turn led to significant improvements in the identification of the four species. However, P. falciparum infections were highly misclassified as mixed infections, P. ovale misclassified as P. vivax and P. vivax similarly misclassified as P. ovale (p < 0.05). These findings suggest that the misclassification of malaria

  14. Equivalent susceptibility of Anopheles gambiae M and S molecular forms and Anopheles arabiensis to Plasmodium falciparum infection in Burkina Faso.

    PubMed

    Gnémé, Awa; Guelbéogo, Wamdaogo M; Riehle, Michelle M; Sanou, Antoine; Traoré, Alphonse; Zongo, Soumanaba; Eiglmeier, Karin; Kabré, Gustave B; Sagnon, N'Falé; Vernick, Kenneth D

    2013-06-14

    The Anopheles gambiae sensu lato (s.l.) species complex in Burkina Faso consists of Anopheles arabiensis, and molecular forms M and S of Anopheles gambiae sensu stricto (s.s.). Previous studies comparing the M and S forms for level of infection with Plasmodium falciparum have yielded conflicting results. Mosquito larvae were sampled from natural pools, reared to adulthood under controlled conditions, and challenged with natural P. falciparum by experimental feeding with blood from gametocyte carriers. Oocyst infection prevalence and intensity was determined one week after infection. DNA from carcasses was genotyped to identify species and molecular form. In total, 7,400 adult mosquitoes grown from wild-caught larvae were challenged with gametocytes in 29 experimental infections spanning four transmission seasons. The overall infection prevalence averaged 40.7% for A. gambiae M form, 41.4% for A. gambiae S form, and 40.1% for A. arabiensis. There was no significant difference in infection prevalence or intensity between the three population groups. Notably, infection experiments in which the population groups were challenged in parallel on the same infective blood displayed less infection difference between population groups, while infections with less balanced composition of population groups had lower statistical power and displayed apparent differences that fluctuated more often from the null average. The study clearly establishes that, at the study site in Burkina Faso, there is no difference in genetic susceptibility to P. falciparum infection between three sympatric population groups of the A. gambiae s.l. complex. Feeding the mosquito groups on the same infective blood meal greatly increases statistical power. Conversely, comparison of the different mosquito groups between, rather than within, infections yields larger apparent difference between mosquito groups, resulting from lower statistical power and greater noise, and could lead to false-positive results

  15. Equivalent susceptibility of Anopheles gambiae M and S molecular forms and Anopheles arabiensis to Plasmodium falciparum infection in Burkina Faso

    PubMed Central

    2013-01-01

    Background The Anopheles gambiae sensu lato (s.l.) species complex in Burkina Faso consists of Anopheles arabiensis, and molecular forms M and S of Anopheles gambiae sensu stricto (s.s.). Previous studies comparing the M and S forms for level of infection with Plasmodium falciparum have yielded conflicting results. Methods Mosquito larvae were sampled from natural pools, reared to adulthood under controlled conditions, and challenged with natural P. falciparum by experimental feeding with blood from gametocyte carriers. Oocyst infection prevalence and intensity was determined one week after infection. DNA from carcasses was genotyped to identify species and molecular form. Results In total, 7,400 adult mosquitoes grown from wild-caught larvae were challenged with gametocytes in 29 experimental infections spanning four transmission seasons. The overall infection prevalence averaged 40.7% for A. gambiae M form, 41.4% for A. gambiae S form, and 40.1% for A. arabiensis. There was no significant difference in infection prevalence or intensity between the three population groups. Notably, infection experiments in which the population groups were challenged in parallel on the same infective blood displayed less infection difference between population groups, while infections with less balanced composition of population groups had lower statistical power and displayed apparent differences that fluctuated more often from the null average. Conclusion The study clearly establishes that, at the study site in Burkina Faso, there is no difference in genetic susceptibility to P. falciparum infection between three sympatric population groups of the A. gambiae s.l. complex. Feeding the mosquito groups on the same infective blood meal greatly increases statistical power. Conversely, comparison of the different mosquito groups between, rather than within, infections yields larger apparent difference between mosquito groups, resulting from lower statistical power and greater noise

  16. α-Thalassemia Impairs the Cytoadherence of Plasmodium falciparum-Infected Erythrocytes

    PubMed Central

    Krause, Michael A.; Diakite, Seidina A. S.; Lopera-Mesa, Tatiana M.; Amaratunga, Chanaki; Arie, Takayuki; Traore, Karim; Doumbia, Saibou; Konate, Drissa; Keefer, Jeffrey R.; Diakite, Mahamadou; Fairhurst, Rick M.

    2012-01-01

    Background α-thalassemia results from decreased production of α-globin chains that make up part of hemoglobin tetramers (Hb; α2β2) and affects up to 50% of individuals in some regions of sub-Saharan Africa. Heterozygous (−α/αα) and homozygous (−α/−α) genotypes are associated with reduced risk of severe Plasmodium falciparum malaria, but the mechanism of this protection remains obscure. We hypothesized that α-thalassemia impairs the adherence of parasitized red blood cells (RBCs) to microvascular endothelial cells (MVECs) and monocytes – two interactions that are centrally involved in the pathogenesis of severe disease. Methods and Findings We obtained P. falciparum isolates directly from Malian children with malaria and used them to infect αα/αα (normal), −α/αα and −α/−α RBCs. We also used laboratory-adapted P. falciparum clones to infect −/−α RBCs obtained from patients with HbH disease. Following a single cycle of parasite invasion and maturation to the trophozoite stage, we tested the ability of parasitized RBCs to bind MVECs and monocytes. Compared to parasitized αα/αα RBCs, we found that parasitized −α/αα, −α/−α and −/−α RBCs showed, respectively, 22%, 43% and 63% reductions in binding to MVECs and 13%, 33% and 63% reductions in binding to monocytes. α-thalassemia was associated with abnormal display of P. falciparum erythrocyte membrane protein 1 (PfEMP1), the parasite’s main cytoadherence ligand and virulence factor, on the surface of parasitized RBCs. Conclusions Parasitized α-thalassemic RBCs show PfEMP1 display abnormalities that are reminiscent of those on the surface of parasitized sickle HbS and HbC RBCs. Our data suggest a model of malaria protection in which α-thalassemia ameliorates the pro-inflammatory effects of cytoadherence. Our findings also raise the possibility that other unstable hemoglobins such as HbE and unpaired α-globin chains (in the case of β-thalassemia) protect against

  17. High frequency of the erythroid silent Duffy antigen genotype and lack of Plasmodium vivax infections in Haiti.

    PubMed

    Weppelmann, Thomas A; Carter, Tamar E; Chen, Zhongsheng; von Fricken, Michael E; Victor, Yves S; Existe, Alexander; Okech, Bernard A

    2013-01-24

    Malaria is a significant public health concern in Haiti where approximately 30,000 cases are reported annually with CDC estimates as high as 200,000. Malaria infections in Haiti are caused almost exclusively by Plasmodium falciparum, while a small number of Plasmodium malariae and an even smaller number of putative Plasmodium vivax infections have been reported. The lack of confirmed P. vivax infections in Haiti could be due to the genetic background of native Haitians. Having descended from West African populations, many Haitians could be Duffy negative due to a single nucleotide polymorphism from thymine to cytosine in the GATA box of the promoter region of the Duffy antigen receptor for chemokines (DARC) gene. This mutation, encoded by the FYES allele, eliminates the expression of the Duffy antigen on erythrocytes, which reduces invasion by P. vivax. This study investigated the frequency of the FYES allele and P. vivax infections in malaria patients with the goal of uncovering factors for the lack of P. vivax infections reported in Haiti. DNA was extracted from dried blood spots collected from malaria patients at four clinic locations in Haiti. The samples were analysed by polymerase chain reaction (PCR) for the presence of the P. vivax small subunit ribosomal RNA gene. PCR, sequencing, and restriction enzyme digestion were used to detect the presence of the FYES allele. Matched samples were examined for both presence of P. vivax and the FYES allele. No cases of P. vivax were detected in any of the samples (0/136). Of all samples tested for the FYES allele, 99.4% had the FYES allele (163/164). Of the matched samples, 99% had the FYES allele (98/99). In this preliminary study, no cases of P. vivax were confirmed by PCR and 99% of the malaria patients tested carried the FYES allele. The high frequency of the FYES allele that silences erythroid expression of the Duffy antigen offers a biologically plausible explanation for the lack of P. vivax infections observed

  18. Predominance of asymptomatic and sub-microscopic infections characterizes the Plasmodium gametocyte reservoir in the Peruvian Amazon

    PubMed Central

    Contreras-Mancilla, Juan José; Ramirez, Roberson; Guzmán-Guzmán, Mitchel; Carrasco-Escobar, Gabriel; Llanos-Cuentas, Alejandro; Vinetz, Joseph M.

    2017-01-01

    Malaria transmission requires that Anopheles mosquitoes ingest Plasmodium gametocyte stages circulating in the human bloodstream. In the context of malaria elimination, understanding the epidemiology of gametocytes relative to all Plasmodium infections and the contribution of asymptomatic and sub-microscopic parasite carriers to the gametocyte reservoir is necessary, especially in low endemic settings with predominance of P.vivax. A 13-month longitudinal study was conducted in two communities (n = 1935 individuals) of Loreto Department, Peru, with five active screenings for Plasmodium infections and gametocyte stages by quantitative real-time PCR (qPCR) and reverse transcription (RT)-qPCR, respectively. Parasite prevalence by qPCR was 7.2% for P.vivax (n = 520/7235; range by survey 6.0%-8.1%) and 3.2% for P.falciparum (n = 235/7235; range by survey 0.4%-7.7%). Sub-microscopic infections accounted for 73.5% of P.vivax (range by survey 60%-89%) and almost the totality of P.falciparum cases. Gametocytes were found in 28.4% P.vivax infections (range by survey 18.7%-34.1%), with a peak of 61.5% in one community at the start of the transmission season. About 59.8% of all P.vivax gametocyte carriers were asymptomatic and 31.9% were sub-microscopic. Age patterns for gametocyte prevalence paralleled asexual stage infections and peaked among >15–25 year old individuals. Asexual parasite density was found to be the strongest predictor for P.vivax gametocyte presence in longitudinal multivariate analysis (odds ratio 2.33 [95% confidence interval 1.96, 2.78]; P<0.001). Despite significant differences in seasonality patterns and P.vivax prevalence found at the local scale, sub-microscopic and asymptomatic infections predominate and contribute significantly to the gametocyte reservoir in different communities of the Peruvian Amazon. Control and elimination campaigns need sensitive tools to detect all infections that escape routine malaria surveillance, which may contribute to

  19. Predominance of asymptomatic and sub-microscopic infections characterizes the Plasmodium gametocyte reservoir in the Peruvian Amazon.

    PubMed

    Rovira-Vallbona, Eduard; Contreras-Mancilla, Juan José; Ramirez, Roberson; Guzmán-Guzmán, Mitchel; Carrasco-Escobar, Gabriel; Llanos-Cuentas, Alejandro; Vinetz, Joseph M; Gamboa, Dionicia; Rosanas-Urgell, Anna

    2017-07-01

    Malaria transmission requires that Anopheles mosquitoes ingest Plasmodium gametocyte stages circulating in the human bloodstream. In the context of malaria elimination, understanding the epidemiology of gametocytes relative to all Plasmodium infections and the contribution of asymptomatic and sub-microscopic parasite carriers to the gametocyte reservoir is necessary, especially in low endemic settings with predominance of P.vivax. A 13-month longitudinal study was conducted in two communities (n = 1935 individuals) of Loreto Department, Peru, with five active screenings for Plasmodium infections and gametocyte stages by quantitative real-time PCR (qPCR) and reverse transcription (RT)-qPCR, respectively. Parasite prevalence by qPCR was 7.2% for P.vivax (n = 520/7235; range by survey 6.0%-8.1%) and 3.2% for P.falciparum (n = 235/7235; range by survey 0.4%-7.7%). Sub-microscopic infections accounted for 73.5% of P.vivax (range by survey 60%-89%) and almost the totality of P.falciparum cases. Gametocytes were found in 28.4% P.vivax infections (range by survey 18.7%-34.1%), with a peak of 61.5% in one community at the start of the transmission season. About 59.8% of all P.vivax gametocyte carriers were asymptomatic and 31.9% were sub-microscopic. Age patterns for gametocyte prevalence paralleled asexual stage infections and peaked among >15-25 year old individuals. Asexual parasite density was found to be the strongest predictor for P.vivax gametocyte presence in longitudinal multivariate analysis (odds ratio 2.33 [95% confidence interval 1.96, 2.78]; P<0.001). Despite significant differences in seasonality patterns and P.vivax prevalence found at the local scale, sub-microscopic and asymptomatic infections predominate and contribute significantly to the gametocyte reservoir in different communities of the Peruvian Amazon. Control and elimination campaigns need sensitive tools to detect all infections that escape routine malaria surveillance, which may contribute to

  20. A lethal case of Plasmodium falciparum infection in a young patient with end-stage renal failure who underwent regular hemodialysis.

    PubMed

    Hartopo, Anggoro Budi; Wijisaksono, Doni Priambodo

    2010-01-01

    Acute renal failure associated with Plasmodium falciparum infection is already well recognized. Nevertheless, end-stage chronic renal failure and falciparum malaria comorbidity is a rare condition. We report a case of Plasmodium falciparum infection in a young male Javanese patient with end-stage chronic renal failure who underwent regular hemodialysis. This rare comorbidity led to rapid deterioration of consciousness and metabolic disturbances which had already existed in end-stage renal failure. Because of the immunosuppressive condition due to organ failure, the patient did not survive despite anti-malarial chemotherapy.

  1. Plasmodium knowlesi and human malaria parasites in Khan Phu, Vietnam: Gametocyte production in humans and frequent co-infection of mosquitoes.

    PubMed

    Maeno, Y; Culleton, R; Quang, N T; Kawai, S; Marchand, R P; Nakazawa, S

    2017-04-01

    Four species of malaria parasite, Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae and Plasmodium knowlesi infect humans living in the Khanh Phu commune, Khanh Hoa Province, Vietnam. The latter species also infects wild macaque monkeys in this region. In order to understand the transmission dynamics of the three species, we attempted to detect gametocytes of the three species in the blood of infected individuals, and sporozoites in the salivary glands of mosquitoes from the same region. For the detection of gametocyte-specific mRNA, we targeted region 3 of pfg377, pvs25, pmg and pks25 as indicators of the presence of P. falciparum, P. vivax, P. malariae and P. knowlesi gametocytes, respectively. Gametocyte-specific mRNA was present in 37, 61, 0 and 47% of people infected with P. falciparum (n = 95), P. vivax (n = 69), P. malariae (n = 6) or P. knowlesi (n = 32), respectively. We found that 70% of mosquitoes that had P. knowlesi in their salivary glands also carried human malaria parasites, suggesting that mosquitoes are infected with P. knowlesi from human infections.

  2. Plasmodium berghei: influence of infection on the oxidant and antioxidants levels in pregnant BALB/c mice.

    PubMed

    Sharma, Lalita; Kaur, Jagdeep; Rishi, Praveen; Shukla, Geeta

    2012-06-01

    Malarial infection during pregnancy has been associated with maternal anemia and death, abortion, still-birth and is a major cause of low birth weight, an important risk factor for infant morbidity and mortality in endemic areas. The present study was designed to delineate the oxidative stress in various organs (liver, spleen, kidney, brain and placenta) of pregnant Plasmodium berghei infected BALB/c mice. It was observed that pregnant-infected mice had higher parasitaemia than nonpregnant-infected mice. Most notably, levels of malondialdehyde (MDA), a measure of lipid peroxidation, reduced glutathione (GSH) and superoxide dismutase (SOD) levels were significantly higher in the liver, spleen, kidney and brain of pregnant-infected mice compared with pregnant mice. Although MDA levels were significantly higher, GSH and SOD levels remained unaltered in the placenta of pregnant-infected mice compared with pregnant mice. Furthermore, catalase activity was significantly lower in all the organs of pregnant-infected mice compared with pregnant mice. Histopathological observations in the organs clearly show the cellular and morphological alterations that may be occurring due to increased lipid peroxidation. Taken together, the data suggest that the increased severity of malarial infection during pregnancy may be due to accentuated oxidative stress.

  3. Natural infection of Plasmodium brasilianum in humans: Man and monkey share quartan malaria parasites in the Venezuelan Amazon.

    PubMed

    Lalremruata, Albert; Magris, Magda; Vivas-Martínez, Sarai; Koehler, Maike; Esen, Meral; Kempaiah, Prakasha; Jeyaraj, Sankarganesh; Perkins, Douglas Jay; Mordmüller, Benjamin; Metzger, Wolfram G

    2015-09-01

    The quartan malaria parasite Plasmodium malariae is the widest spread and best adapted human malaria parasite. The simian Plasmodium brasilianum causes quartan fever in New World monkeys and resembles P. malariae morphologically. Since the genetics of the two parasites are nearly identical, differing only in a range of mutations expected within a species, it has long been speculated that the two are the same. However, no naturally acquired infection with parasites termed as P. brasilianum has been found in humans until now. We investigated malaria cases from remote Yanomami indigenous communities of the Venezuelan Amazon and analyzed the genes coding for the circumsporozoite protein (CSP) and the small subunit of ribosomes (18S) by species-specific PCR and capillary based-DNA sequencing. Based on 18S rRNA gene sequencing, we identified 12 patients harboring malaria parasites which were 100% identical with P. brasilianum isolated from the monkey, Alouatta seniculus. Translated amino acid sequences of the CS protein gene showed identical immunodominant repeat units between quartan malaria parasites isolated from both humans and monkeys. This study reports, for the first time, naturally acquired infections in humans with parasites termed as P. brasilianum. We conclude that quartan malaria parasites are easily exchanged between humans and monkeys in Latin America. We hypothesize a lack of host specificity in mammalian hosts and consider quartan malaria to be a true anthropozoonosis. Since the name P. brasilianum suggests a malaria species distinct from P. malariae, we propose that P. brasilianum should have a nomenclatorial revision in case further research confirms our findings. The expansive reservoir of mammalian hosts discriminates quartan malaria from other Plasmodium spp. and requires particular research efforts.

  4. Immunization against a merozoite sheddase promotes multiple invasion of red blood cells and attenuates Plasmodium infection in mice.

    PubMed

    Smith, Ryan C; Colón-López, Daisy D; Bosch, Jürgen

    2014-08-12

    Subtilisin-like protease 2 (SUB2) is a conserved serine protease utilized by Plasmodium parasites as a surface sheddase required for successful merozoite invasion of host red blood cells and has been implicated in ookinete invasion of the mosquito midgut. To determine if SUB2 is a suitable vaccine target to interfere with malaria parasite development, the effects of SUB2-immunization on the Plasmodium life cycle were examined in its vertebrate and invertebrate hosts. Swiss Webster mice were immunized with SUB2 peptides conjugated to Keyhole limpet hemocyanin (KLH) or KLH alone, and then challenged with Plasmodium berghei. To determine the effects of immunization on parasite development, infected mice were evaluated by blood film and Giemsa staining. In addition, collected immune sera were used to perform passive immunization experiments in non-immunized, P. berghei-infected mice to determine the potential role of SUB2 in parasite development in the mosquito. Following P. berghei challenge, SUB2-immunized mice develop a lower parasitaemia and show improved survival when compared to control immunized mice. Moreover, SUB2 immunization results in an increase in the number of multiply invaded red blood cells, suggesting that SUB2 antibodies interfere with merozoite invasion. Passive immunization experiments imply that SUB2 may not have a major role in ookinete invasion, but this requires further investigation. By interfering with red blood cell invasion, immunization against SUB2 limits malaria parasite development and confers protection from severe malaria. Together, these results provide proof-of-principle evidence for future investigation into the use of SUB2 as a vaccine or drug target to interrupt parasite development in more relevant human malaria models.

  5. Post-deployment effectiveness of malaria control interventions on Plasmodium infections in Madagascar: a comprehensive phase IV assessment.

    PubMed

    Kesteman, Thomas; Randrianarivelojosia, Milijaona; Piola, Patrice; Rogier, Christophe

    2016-06-16

    Because international funding for malaria control is plateauing, affected countries that receive foreign funding are expected to maintain a constant budget while continuing to reduce Plasmodium transmission. To investigate the appropriateness of a malaria control policy in Madagascar, the effectiveness of all currently deployed malaria control interventions (MCIs) was measured. A nationwide cross-sectional survey was conducted in 2012-2013 at 62 sites throughout Madagascar. A total of 15,746 individuals of all ages were tested for Plasmodium infection using rapid diagnostic tests and were interviewed about their use of long-lasting insecticidal nets (LLINs), indoor residual spraying (IRS), intermittent preventive treatment of pregnant women (IPTp), and exposure to information, education and communication (IEC) campaigns. The association between Plasmodium infection and MCI exposure was calculated using multivariate multilevel models, and the protective effectiveness (PE) of an intervention was defined as one minus the odds ratio of this association. The individual PE of regular LLIN use was high and significant (41 %, 95 % confidence interval [CI] 23-54), whereas its community PE was not. The PE of IRS at the household level was significant in one transmission pattern only (44 %, 95 % CI 11-65), and the community PE with high IRS coverage (>75 %) was high and significant overall (78 %, 95 % CI 44-91). Using LLINs after IRS increased the PE, and the reciprocal was also true. The maternal PE of IPTp was high but non-significant (65 %, 95 % CI -32 to 91). The PE of IEC was low, non-significant and restricted to certain areas (24 %, 95 % CI -34 to 57). This snapshot of the effectiveness of MCIs confirms that integrated vector control is required in malaria control policies in Madagascar and suggests combining MCIs when one is questionable. Policymakers should consider the local effectiveness of all deployed MCIs through a similar phase IV assessment.

  6. Natural infection of Plasmodium brasilianum in humans: Man and monkey share quartan malaria parasites in the Venezuelan Amazon

    PubMed Central

    Lalremruata, Albert; Magris, Magda; Vivas-Martínez, Sarai; Koehler, Maike; Esen, Meral; Kempaiah, Prakasha; Jeyaraj, Sankarganesh; Perkins, Douglas Jay; Mordmüller, Benjamin; Metzger, Wolfram G.

    2015-01-01

    Background The quartan malaria parasite Plasmodium malariae is the widest spread and best adapted human malaria parasite. The simian Plasmodium brasilianum causes quartan fever in New World monkeys and resembles P. malariae morphologically. Since the genetics of the two parasites are nearly identical, differing only in a range of mutations expected within a species, it has long been speculated that the two are the same. However, no naturally acquired infection with parasites termed as P. brasilianum has been found in humans until now. Methods We investigated malaria cases from remote Yanomami indigenous communities of the Venezuelan Amazon and analyzed the genes coding for the circumsporozoite protein (CSP) and the small subunit of ribosomes (18S) by species-specific PCR and capillary based-DNA sequencing. Findings Based on 18S rRNA gene sequencing, we identified 12 patients harboring malaria parasites which were 100% identical with P. brasilianum isolated from the monkey, Alouatta seniculus. Translated amino acid sequences of the CS protein gene showed identical immunodominant repeat units between quartan malaria parasites isolated from both humans and monkeys. Interpretation This study reports, for the first time, naturally acquired infections in humans with parasites termed as P. brasilianum. We conclude that quartan malaria parasites are easily exchanged between humans and monkeys in Latin America. We hypothesize a lack of host specificity in mammalian hosts and consider quartan malaria to be a true anthropozoonosis. Since the name P. brasilianum suggests a malaria species distinct from P. malariae, we propose that P. brasilianum should have a nomenclatorial revision in case further research confirms our findings. The expansive reservoir of mammalian hosts discriminates quartan malaria from other Plasmodium spp. and requires particular research efforts. PMID:26501116

  7. Identifying risk factors for Plasmodium infection and anaemia in Kinshasa, Democratic Republic of Congo.

    PubMed

    Ferrari, Giovanfrancesco; Ntuku, Henry M T; Ross, Amanda; Schmidlin, Sandro; Kalemwa, Didier M; Tshefu, Antoinette K; Lengeler, Christian

    2016-07-15

    There is little data on the risk factors for malaria infection in large cities in central Africa and in all age groups. There may be different associations with the risk factors for areas with different malaria transmission intensities such as the effect of fever or age. This study aimed at identifying risk factors associated with Plasmodium infection and anaemia among children 6-59 months and individuals aged older than 5 years in Kinshasa, a large city with heterogeneity in malaria prevalence. This study analysed data from 3342 children aged 6-59 months from 25 non-rural health zones (HZs) and for 816 individuals aged older than 5 years from two HZs in Kinshasa (non-rural), collected during a cross sectional malaria survey in 2011. Logistic regression with random effects was used to investigate predictors for malaria and anaemia. Differences in risk factors in areas with a prevalence of less than 10 and 10 % or greater were investigated. There was evidence of a different age-pattern in the two transmission settings. For children under 5 years, the highest prevalence of malaria was observed in the 48-59 months group in both transmission settings, but it increased more gently for the lower transmission HZs (p = 0.009). In a separate analysis in children over 5 years in two selected HZs, the peak prevalence was in 5-9 years old in the higher transmission setting and in 15-19 years old in the lower transmission setting. Reported fever was associated with malaria in both transmission strata, with no evidence of a difference in these associations (p = 0.71); however in children older than 5 years there was a significant interaction with a stronger association in the low transmission HZ. Insecticide-treated net (ITN) use was associated with a lower risk of malaria infection in children 6-59 months in the high transmission HZs. Similar estimates were found in children over 5 years and the lower transmission HZ but the associations there were not

  8. Mixed species radioiodine air sampling readout and dose assessment system

    DOEpatents

    Distenfeld, Carl H.; Klemish, Jr., Joseph R.

    1978-01-01

    This invention provides a simple, reliable, inexpensive and portable means and method for determining the thyroid dose rate of mixed airborne species of solid and gaseous radioiodine without requiring highly skilled personnel, such as health physicists or electronics technicians. To this end, this invention provides a means and method for sampling a gas from a source of a mixed species of solid and gaseous radioiodine for collection of the mixed species and readout and assessment of the emissions therefrom by cylindrically, concentrically and annularly molding the respective species around a cylindrical passage for receiving a conventional probe-type Geiger-Mueller radiation detector.

  9. MAPK phosphotase 5 deficiency contributes to protection against blood-stage Plasmodium yoelii 17XL infection in mice.

    PubMed

    Cheng, Qianqian; Zhang, Qingfeng; Xu, Xindong; Yin, Lan; Sun, Lin; Lin, Xin; Dong, Chen; Pan, Weiqing

    2014-04-15

    Cell-mediated immunity plays a crucial role in the development of host resistance to asexual blood-stage malaria infection. However, little is known of the regulatory factors involved in this process. In this study, we investigated the impact of MAPK phosphotase 5 (MKP5) on protective immunity against a lethal Plasmodium yoelii 17XL blood-stage infection using MKP5 knockout C57BL/6 mice. Compared with wild-type control mice, MKP5 knockout mice developed significantly lower parasite burdens with prolonged survival times. We found that this phenomenon correlated with a rapid and strong IFN-γ-dependent cellular immune response during the acute phase of infection. Inactivation of IFN-γ by the administration of a neutralizing Ab significantly reduced the protective effects in MKP5 knockout mice. By analyzing IFN-γ production in innate and adaptive lymphocyte subsets, we observed that MKP5 deficiency specifically enhanced the IFN-γ response mediated by CD4+ T cells, which was attributable to the increased stimulatory capacity of splenic CD11c+ dendritic cells. Furthermore, following vaccination with whole blood-stage soluble plasmodial Ag, MKP5 knockout mice acquired strongly enhanced Ag-specific immune responses and a higher level of protection against subsequent P. yoelii 17XL challenge. Finally, we found the enhanced response mediated by MKP5 deficiency resulted in a lethal consequence in mice when infected with nonlethal P. yoelii 17XNL. Thus, our data indicate that MKP5 is a potential regulator of immune resistance against Plasmodium infection in mice, and that an understanding of the role of MKP5 in manipulating anti-malaria immunity may provide valuable information on the development of better control strategies for human malaria.

  10. Establishment efficiency among clones of the malaria parasite, Plasmodium mexicanum, for mixed-clone infections in its natural lizard host.

    PubMed

    Hicks, Nathan D; Schall, Jos J

    2013-12-01

    Within genetically diverse infections of malaria parasites ( Plasmodium spp.), the relative proportions of genetic clones in the vertebrate host's blood can influence clonal competition, transmission success, gametocyte sex ratio, and virulence. Clonal proportions depend on establishment success of each clone when they enter a new host and on subsequent differences in rates of asexual replication and clearance. Both of these life history traits could be influenced by clone genotype. To assess genetic (clonal) influences on both establishment success and later changes in relative proportion for the lizard malaria parasite Plasmodium mexicanum , 7 naturally infected fence lizards harboring a single clone of P. mexicanum served as donors to initiate replicate experimental infections containing each of the clones and combinations of 2 clones. Measured were relative establishment success of each clone, change in relative proportions over time, and rate of increase of parasite density and total parasitemia. Relative clonal proportions were determined using microsatellite markers. Rates of increase in the parasitemia and degree of change in relative proportions were not correlated, so both rapidly and slowly growing infections could show either little or substantial change in clonal proportions over time. There was a significant clone effect on establishment efficiency but not on later changes in relative proportions. These results argue for a combination of genetic and environmental (host) effects on the success of P. mexicanum clones in genetically complex infections. The maintenance of genetic variation for establishment success, but not subsequent replication rate or shifts in relative proportion, suggests trade-offs between these traits during life history evolution of malaria parasites.

  11. Application of heparin as a dual agent with antimalarial and liposome targeting activities toward Plasmodium-infected red blood cells.

    PubMed

    Marques, Joana; Moles, Ernest; Urbán, Patricia; Prohens, Rafel; Busquets, Maria Antònia; Sevrin, Chantal; Grandfils, Christian; Fernàndez-Busquets, Xavier

    2014-11-01

    Heparin had been demonstrated to have antimalarial activity and specific binding affinity for Plasmodium-infected red blood cells (pRBCs) vs. non-infected erythrocytes. Here we have explored if both properties could be joined into a drug delivery strategy where heparin would have a dual role as antimalarial and as a targeting element of drug-loaded nanoparticles. Confocal fluorescence and transmission electron microscopy data show that after 30 min of being added to living pRBCs fluorescein-labeled heparin colocalizes with the intracellular parasites. Heparin electrostatically adsorbed onto positively charged liposomes containing the cationic lipid 1,2-dioleoyl-3-trimethylammonium-propane and loaded with the antimalarial drug primaquine was capable of increasing three-fold the activity of encapsulated drug in Plasmodium falciparum cultures. At concentrations below those inducing anticoagulation of mouse blood in vivo, parasiticidal activity was found to be the additive result of the separate activities of free heparin as antimalarial and of liposome-bound heparin as targeting element for encapsulated primaquine. Malaria remains an enormous global public health concern. In this study, a novel functionalized heparin formulation used as drug delivery agent for primaquine was demonstrated to result in threefold increased drug activity in cell cultures, and in a murine model it was able to provide these benefits in concentrations below what would be required for anticoagulation. Further studies are needed determine if this approach is applicable in the human disease as well. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Griseofulvin impairs intraerythrocytic growth of Plasmodium falciparum through ferrochelatase inhibition but lacks activity in an experimental human infection study

    PubMed Central

    Smith, Clare M.; Jerkovic, Ante; Truong, Thy Thuc; Foote, Simon J.; McCarthy, James S.; McMorran, Brendan J.

    2017-01-01

    Griseofulvin, an orally active antifungal drug used to treat dermatophyte infections, has a secondary effect of inducing cytochrome P450-mediated production of N-methyl protoporphyrin IX (N-MPP). N-MPP is a potent competitive inhibitor of the heme biosynthetic-enzyme ferrochelatase, and inhibits the growth of cultured erythrocyte stage Plasmodium falciparum. Novel drugs against Plasmodium are needed to achieve malaria elimination. Thus, we investigated whether griseofulvin shows anti-plasmodial activity. We observed that the intraerythrocytic growth of P. falciparum is inhibited in red blood cells pretreated with griseofulvin in vitro. Treatment with 100 μM griseofulvin was sufficient to prevent parasite growth and induce the production of N-MPP. Inclusion of the ferrochelatase substrate PPIX blocked the inhibitory activity of griseofulvin, suggesting that griseofulvin exerts its activity through the N-MPP-dependent inhibition of ferrochelatase. In an ex-vivo study, red blood cells from griseofulvin-treated subjects were refractory to the growth of cultured P. falciparum. However, in a clinical trial griseofulvin failed to show either therapeutic or prophylactic effect in subjects infected with blood stage P. falciparum. Although the development of griseofulvin as an antimalarial is not warranted, it represents a novel inhibitor of P. falciparum growth and acts via the N-MPP-dependent inhibition of ferrochelatase. PMID:28176804

  13. Bone marrow suppression and severe anaemia associated with persistent Plasmodium falciparum infection in African children with microscopically undetectable parasitaemia

    PubMed Central

    Helleberg, Marie; Goka, Bamenla Q; Akanmori, Bartholomew D; Obeng-Adjei, George; Rodriques, Onike; Kurtzhals, Jorgen AL

    2005-01-01

    Background Severe anaemia can develop in the aftermath of Plasmodium falciparum malaria because of protracted bone marrow suppression, possibly due to residual subpatent parasites. Materials and methods Blood was collected from patients with recent malaria and negative malaria microscopy. Detection of the Plasmodium antigens, lactate dehydrogenase (Optimal®), aldolase and histidine rich protein 2 (Now malaria®) were used to differentiate between patients with (1) no malaria, (2) recent cleared malaria, (3) persistent P. falciparum infection. Red cell distribution width (RDW), plasma levels of soluble transferrin receptor (sTfR) and erythropoietin (EPO) were measured as markers of erythropoiesis. Interleukin (IL) 10 and tumour necrosis factor (TNF)α were used as inflammation markers. Results EPO was correlated with haemoglobin, irrespective of malaria (R = -0.36, P < 0.001). Persistent P. falciparum infection, but not recent malaria without residual parasites, was associated with bone marrow suppression i.e., low RDW (P < 0.001 vs. P = 0.56) and sTfR (P = 0.02 vs. P = 0.36). TNF-α and IL-10 levels were not associated with bone marrow suppression. Conclusion In the treatment of malaria, complete eradication of parasites may prevent subsequent development of anaemia. Severely anaemic children may benefit from antimalarial treatment if antigen tests are positive, even when no parasites can be demonstrated by microscopy. PMID:16321150

  14. Crystal Structure of Arginase from Plasmodium falciparum and Implications for l-Arginine Depletion in Malarial Infection

    SciTech Connect

    Dowling, Daniel P.; Ilies, Monica; Olszewski, Kellen L.; Portugal, Silvia; Mota, Maria M.; Llinas, Manuel; Christianson, David W.

    2010-09-03

    The 2.15 {angstrom} resolution crystal structure of arginase from Plasmodium falciparum, the parasite that causes cerebral malaria, is reported in complex with the boronic acid inhibitor 2(S)-amino-6-boronohexanoic acid (ABH) (K{sub d} = 11 {micro}M). This is the first crystal structure of a parasitic arginase. Various protein constructs were explored to identify an optimally active enzyme form for inhibition and structural studies and to probe the structure and function of two polypeptide insertions unique to malarial arginase: a 74-residue low-complexity region contained in loop L2 and an 11-residue segment contained in loop L8. Structural studies indicate that the low-complexity region is largely disordered and is oriented away from the trimer interface; its deletion does not significantly compromise enzyme activity. The loop L8 insertion is located at the trimer interface and makes several intra- and intermolecular interactions important for enzyme function. In addition, we also demonstrate that arg- Plasmodium berghei sporozoites show significantly decreased liver infectivity in vivo. Therefore, inhibition of malarial arginase may serve as a possible candidate for antimalarial therapy against liver-stage infection, and ABH may serve as a lead for the development of inhibitors.

  15. Inference of the Oxidative Stress Network in Anopheles stephensi upon Plasmodium Infection

    PubMed Central

    Shrinet, Jatin; Nandal, Umesh Kumar; Adak, Tridibes; Bhatnagar, Raj K.; Sunil, Sujatha

    2014-01-01

    Ookinete invasion of Anopheles midgut is a critical step for malaria transmission; the parasite numbers drop drastically and practically reach a minimum during the parasite's whole life cycle. At this stage, the parasite as well as the vector undergoes immense oxidative stress. Thereafter, the vector undergoes oxidative stress at different time points as the parasite invades its tissues during the parasite development. The present study was undertaken to reconstruct the network of differentially expressed genes involved in oxidative stress in Anopheles stephensi during Plasmodium development and maturation in the midgut. Using high throughput next generation sequencing methods, we generated the transcriptome of the An. stephensi midgut during Plasmodium vinckei petteri oocyst invasion of the midgut epithelium. Further, we utilized large datasets available on public domain on Anopheles during Plasmodium ookinete invasion and Drosophila datasets and arrived upon clusters of genes that may play a role in oxidative stress. Finally, we used support vector machines for the functional prediction of the un-annotated genes of An. stephensi. Integrating the results from all the different data analyses, we identified a total of 516 genes that were involved in oxidative stress in An. stephensi during Plasmodium development. The significantly regulated genes were further extracted from this gene cluster and used to infer an oxidative stress network of An. stephensi. Using system biology approaches, we have been able to ascertain the role of several putative genes in An. stephensi with respect to oxidative stress. Further experimental validations of these genes are underway. PMID:25474020

  16. Plasmodium falciparum infection increases Anopheles gambiae attraction to nectar sources and sugar uptake

    USDA-ARS?s Scientific Manuscript database

    Plasmodium parasites are known to manipulate the behaviour of their vectors so as to enhance their transmission. However, it is unknown if this vector manipulation also affects mosquito-plant interaction and sugar uptake. Dual-choice olfactometer and probing assays were used to study plant seeking b...

  17. Subclinical Plasmodium falciparum infections act as year-round reservoir for malaria in the hypoendemic Chittagong Hill districts of Bangladesh.

    PubMed

    Shannon, Kerry L; Khan, Wasif A; Sack, David A; Alam, M Shafiul; Ahmed, Sabeena; Prue, Chai Shwai; Khyang, Jacob; Ram, Malathi; Haq, M Zahirul; Akter, Jasmin; Glass, Gregory E; Shields, Timothy M; Galagan, Sean R; Nyunt, Myaing M; Sullivan, David J

    2016-08-01

    An analysis of the risk factors and seasonal and spatial distribution of individuals with subclinical malaria in hypoendemic Bangladesh was performed. From 2009 to 2012, active malaria surveillance without regard to symptoms was conducted on a random sample (n=3971) and pregnant women (n=589) during a cohort malaria study in a population of 24000. The overall subclinical Plasmodium falciparum malaria point prevalence was 1.0% (n=35), but was 3.2% (n=18) for pregnant women. The estimated incidence was 39.9 per 1000 person-years for the overall population. Unlike symptomatic malaria, with a marked seasonal pattern, subclinical infections did not show a seasonal increase during the rainy season. Sixty-nine percent of those with subclinical P. falciparum infections reported symptoms commonly associated with malaria compared to 18% without infection. Males, pregnant women, jhum cultivators, and those living closer to forests and at higher elevations had a higher prevalence of subclinical infection. Hypoendemic subclinical malaria infections were associated with a number of household and demographic factors, similar to symptomatic cases. Unlike clinical symptomatic malaria, which is highly seasonal, these actively detected infections were present year-round, made up the vast majority of infections at any given time, and likely acted as reservoirs for continued transmission. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  18. Infectivity of Plasmodium falciparum in Malaria-Naive Individuals Is Related to Knob Expression and Cytoadherence of the Parasite

    PubMed Central

    Stanisic, Danielle I.; Gerrard, John; Fink, James; Griffin, Paul M.; Liu, Xue Q.; Sundac, Lana; Sekuloski, Silvana; Rodriguez, Ingrid B.; Pingnet, Jolien; Yang, Yuedong; Zhou, Yaoqi; Trenholme, Katharine R.; Wang, Claire Y. T.; Hackett, Hazel; Chan, Jo-Anne A.; Langer, Christine; Hanssen, Eric; Hoffman, Stephen L.; Beeson, James G.; McCarthy, James S.

    2016-01-01

    Plasmodium falciparum is the most virulent human malaria parasite because of its ability to cytoadhere in the microvasculature. Nonhuman primate studies demonstrated relationships among knob expression, cytoadherence, and infectivity. This has not been examined in humans. Cultured clinical-grade P. falciparum parasites (NF54, 7G8, and 3D7B) and ex vivo-derived cell banks were characterized. Knob and knob-associated histidine-rich protein expression, CD36 adhesion, and antibody recognition of parasitized erythrocytes (PEs) were evaluated. Parasites from the cell banks were administered to malaria-naive human volunteers to explore infectivity. For the NF54 and 3D7B cell banks, blood was collected from the study participants for in vitro characterization. All parasites were infective in vivo. However, infectivity of NF54 was dramatically reduced. In vitro characterization revealed that unlike other cell bank parasites, NF54 PEs lacked knobs and did not cytoadhere. Recognition of NF54 PEs by immune sera was observed, suggesting P. falciparum erythrocyte membrane protein 1 expression. Subsequent recovery of knob expression and CD36-mediated adhesion were observed in PEs derived from participants infected with NF54. Knobless cell bank parasites have a dramatic reduction in infectivity and the ability to adhere to CD36. Subsequent infection of malaria-naive volunteers restored knob expression and CD36-mediated cytoadherence, thereby showing that the human environment can modulate virulence. PMID:27382019

  19. Severe anaemia associated with Plasmodium falciparum infection in children: consequences for additional blood sampling for research.

    PubMed

    Kuijpers, Laura Maria Francisca; Maltha, Jessica; Guiraud, Issa; Kaboré, Bérenger; Lompo, Palpouguini; Devlieger, Hugo; Van Geet, Chris; Tinto, Halidou; Jacobs, Jan

    2016-06-02

    Plasmodium falciparum infection may cause severe anaemia, particularly in children. When planning a diagnostic study on children suspected of severe malaria in sub-Saharan Africa, it was questioned how much blood could be safely sampled; intended blood volumes (blood cultures and EDTA blood) were 6 mL (children aged <6 years) and 10 mL (6-12 years). A previous review [Bull World Health Organ. 89: 46-53. 2011] recommended not to exceed 3.8 % of total blood volume (TBV). In a simulation exercise using data of children previously enrolled in a study about severe malaria and bacteraemia in Burkina Faso, the impact of this 3.8 % safety guideline was evaluated. For a total of 666 children aged >2 months to <12 years, data of age, weight and haemoglobin value (Hb) were available. For each child, the estimated TBV (TBVe) (mL) was calculated by multiplying the body weight (kg) by the factor 80 (ml/kg). Next, TBVe was corrected for the degree of anaemia to obtain the functional TBV (TBVf). The correction factor consisted of the rate 'Hb of the child divided by the reference Hb'; both the lowest ('best case') and highest ('worst case') reference Hb values were used. Next, the exact volume that a 3.8 % proportion of this TBVf would present was calculated and this volume was compared to the blood volumes that were intended to be sampled. When applied to the Burkina Faso cohort, the simulation exercise pointed out that in 5.3 % (best case) and 11.4 % (worst case) of children the blood volume intended to be sampled would exceed the volume as defined by the 3.8 % safety guideline. Highest proportions would be in the age groups 2-6 months (19.0 %; worst scenario) and 6 months-2 years (15.7 %; worst case scenario). A positive rapid diagnostic test for P. falciparum was associated with an increased risk of violating the safety guideline in the worst case scenario (p = 0.016). Blood sampling in children for research in P. falciparum endemic settings may easily violate

  20. The seroprevalence of avipoxvirus and its association with avian malaria (Plasmodium spp.) infection in introduced passerine birds in the southern regions of the North Island of New Zealand.

    PubMed

    Ha, H J; Banda, M; Alley, M R; Howe, L; Gartrell, B D

    2013-03-01

    Blood samples were collected from 65 free-ranging birds from six species in the southern North Island of New Zealand. Sera from the birds were tested for the presence of avipoxvirus (APV) antibodies by enzyme-linked immunosorbent assay (ELISA), and blood cells from 55 birds were also tested for Plasmodium spp. by PCR. Forty-five birds (69.2%) tested seropositive to APV. Song thrushes (Turdus philomelos) presented the highest seroprevalence at 100% (4/4), followed by Eurasian blackbirds (Turdus merula) (96.86%, 31/32), chaffinches (Fringilla coelebs) (54.55%, 6/11), starlings (Sturnus vulgaris) (25%, 3/12), greenfinches (Carduelis chloris) (25%, 1/4), and European goldfinches (Carduelis carduelis) (0%, 0/2). Plasmodium spp. DNA was detected in 15/55 birds (27.3%), including 11 Eurasian blackbirds, one song thrush, and three starlings. Eight Eurasian blackbird isolates (73%) grouped within the subgenus Novyella. Two Eurasian blackbird isolates and the song thrush isolate clustered within a different group with previously reported lineages LINN1 and AFTRU5. In addition, all three starling isolates clustered within the well-characterized lineage Plasmodium (Huffia) elongatum GRW06. All Plasmodium-positive Eurasian blackbirds and the song thrush were seropositive to APV, whereas only 67% of Plasmodium-positive starlings showed evidence of previous exposure to APV. A significant relationship between birds seropositive to APV and birds infected by Plasmodium spp. was observed (chi2 = 5.69, df = 1, P = 0.0086). To the authors' knowledge this is the first report describing the seroprevalence of APV and its association with Plasmodium spp. infection in introduced bird species in New Zealand.

  1. High-throughput multi-parameter flow-cytometric analysis from micro-quantities of plasmodium-infected blood.

    PubMed

    Apte, Simon H; Groves, Penny L; Roddick, Joanne S; P da Hora, Vanusa; Doolan, Denise L

    2011-10-01

    Despite significant technological and conceptual advances over the last century, evaluation of the efficacy of anti-malarial vaccines or drugs continues to rely principally on direct microscopic visualisation of parasites on thick and/or thin Giemsa-stained blood smears. This requires technical expertise of the microscopist, is highly subjective and error-prone, and does not account for aberrations such as anaemia. Many published methods have shown that flow cytometric analysis of blood is a highly versatile method that can readily detect nucleic acid-stained parasitised red blood cells within cultured cell populations and in ex-vivo samples. However several impediments, including the difficulty in distinguishing reticulocytes from infected red blood cells and the fickle nature of red blood cells, have precluded the development and universal adoption of flow-cytometric based assays for ex-vivo sample analysis. We have developed a novel high-throughput assay for the flow cytometric assessment of blood that overcomes these impediments by utilising the unique properties of the nucleic acid stain DAPI to differentially stain RNA and DNA, combined with novel fixation and analysis protocols. The assay allows the rapid and reliable analysis of multiple parameters from micro-volumes of blood, including: parasitaemia, platelet count, reticulocyte count, normocyte count, white blood cell count and delineation of subsets and phenotypic markers including, but not limited to, CD4(+) and CD8(+) T cells, and the expression of phenotypic markers such as PD-L1 or intracellular cytokines. The assay requires less than one drop of blood and is therefore suitable for short interval time-course experiments and allows the progression of infection and immune responses to be closely monitored in the laboratory or cytometer-equipped field locations. Herein, we describe the technique and demonstrate its application in vaccinology and with a range of rodent and human parasite species

  2. Modulation of Whole-Cell Currents in Plasmodium Falciparum-Infected Human Red Blood Cells by Holding Potential and Serum

    PubMed Central

    Staines, Henry M; Powell, Trevor; Clive Ellory, J; Egée, Stéphane; Lapaix, Franck; Decherf, Gaëtan; Thomas, Serge L Y; Duranton, Christophe; Lang, Florian; Huber, Stephan M

    2003-01-01

    Recent electrophysiological studies have identified novel ion channel activity in the host plasma membrane of Plasmodium falciparum-infected human red blood cells (RBCs). However, conflicting data have been published with regard to the characteristics of induced channel activity measured in the whole-cell configuration of the patch-clamp technique. In an effort to establish the reasons for these discrepancies, we demonstrate here two factors that have been found to modulate whole-cell recordings in malaria-infected RBCs. Firstly, negative holding potentials reduced inward currents (i.e. at negative potentials), although this result was highly complex. Secondly, the addition of human serum increased outward currents (i.e. at positive potentials) by approximately 4-fold and inward currents by approximately 2-fold. These two effects may help to resolve the conflicting data in the literature, although further investigation is required to understand the underlying mechanisms and their physiological relevance in detail. PMID:12937282

  3. Artemisinin-resistant Plasmodium falciparum clinical isolates can infect diverse mosquito vectors of Southeast Asia and Africa.

    PubMed

    St Laurent, Brandyce; Miller, Becky; Burton, Timothy A; Amaratunga, Chanaki; Men, Sary; Sovannaroth, Siv; Fay, Michael P; Miotto, Olivo; Gwadz, Robert W; Anderson, Jennifer M; Fairhurst, Rick M

    2015-10-20

    Artemisinin-resistant Plasmodium falciparum parasites are rapidly spreading in Southeast Asia, yet nothing is known about their transmission. This knowledge gap and the possibility that these parasites will spread to Africa endanger global efforts to eliminate malaria. Here we produce gametocytes from parasite clinical isolates that displayed artemisinin resistance in patients and in vitro, and use them to infect native and non-native mosquito vectors. We show that contemporary artemisinin-resistant isolates from Cambodia develop and produce sporozoites in two Southeast Asian vectors, Anopheles dirus and Anopheles minimus, and the major African vector, Anopheles coluzzii (formerly Anopheles gambiae M). The ability of artemisinin-resistant parasites to infect such highly diverse Anopheles species, combined with their higher gametocyte prevalence in patients, may explain the rapid expansion of these parasites in Cambodia and neighbouring countries, and further compromise efforts to prevent their global spread.

  4. Artemisinin-resistant Plasmodium falciparum clinical isolates can infect diverse mosquito vectors of Southeast Asia and Africa

    PubMed Central

    St. Laurent, Brandyce; Miller, Becky; Burton, Timothy A.; Amaratunga, Chanaki; Men, Sary; Sovannaroth, Siv; Fay, Michael P.; Miotto, Olivo; Gwadz, Robert W.; Anderson, Jennifer M.; Fairhurst, Rick M.

    2015-01-01

    Artemisinin-resistant Plasmodium falciparum parasites are rapidly spreading in Southeast Asia, yet nothing is known about their transmission. This knowledge gap and the possibility that these parasites will spread to Africa endanger global efforts to eliminate malaria. Here we produce gametocytes from parasite clinical isolates that displayed artemisinin resistance in patients and in vitro, and use them to infect native and non-native mosquito vectors. We show that contemporary artemisinin-resistant isolates from Cambodia develop and produce sporozoites in two Southeast Asian vectors, Anopheles dirus and Anopheles minimus, and the major African vector, Anopheles coluzzii (formerly Anopheles gambiae M). The ability of artemisinin-resistant parasites to infect such highly diverse Anopheles species, combined with their higher gametocyte prevalence in patients, may explain the rapid expansion of these parasites in Cambodia and neighbouring countries, and further compromise efforts to prevent their global spread. PMID:26485448

  5. Differential immune response associated to malaria outcome is detectable in peripheral blood following Plasmodium yoelii infection in mice.

    PubMed

    Azcárate, Isabel G; Marín-García, Patricia; Kamali, Alí N; Pérez-Benavente, Susana; Puyet, Antonio; Diez, Amalia; Bautista, José M

    2014-01-01

    Malaria infection in humans elicits a wide range of immune responses that can be detected in peripheral blood, but we lack detailed long-term follow-up data on the primary and subsequent infections that lead to naturally acquired immunity. Studies on antimalarial immune responses in mice have been based on models yielding homogenous infection profiles. Here, we present a mouse model in which a heterogeneous course of Plasmodium yoelii lethal malaria infection is produced in a non-congenic ICR strain to allow comparison among different immunological and clinical outcomes. Three different disease courses were observed ranging from a fatal outcome, either early or late, to a self-resolved infection that conferred long-term immunity against re-infection. Qualitative and quantitative changes produced in leukocyte subpopulations and cytokine profiles detected in peripheral blood during the first week of infection revealed that monocytes, dendritic cells and immature B cells were the main cell subsets present in highly-parasitized mice dying in the first week after infection. Besides, CD4(+)CD25(high) T cells expanded at an earlier time point in early deceased mice than in surviving mice and expressed higher levels of intracellular Foxp3 protein. In contrast, survivors showed a limited increase of cytokines release and stable circulating innate cells. From the second week of infection, mice that would die or survive showed similar immune profiles, although CD4(+)CD25(high) T cells number increased earlier in mice with the worst prognosis. In surviving mice the expansion of activated circulating T cell and switched-class B cells with a long-term protective humoral response from the second infection week is remarkable. Our results demonstrate that the follow-up studies of immunological blood parameters during a malaria infection can offer information about the course of the pathological process and the immune response.

  6. Plasmodium falciparum: effect of chloroquine, halofantrine and pyrimethamine on the infectivity of gametocytes for Anopheles stephensi mosquitoes.

    PubMed

    Chutmongkonkul, M; Maier, W A; Seitz, H M

    1992-04-01

    The activity of chloroquine, halofantrine and pyrimethamine against the gametocytes and sporogonic stages of Plasmodium falciparum (strain NF54) was tested. Five-day-old gametocytes (stages I and II) from in vitro cultures were exposed to the drugs for 48 hours. The effect of the drugs on gametocyte development was assessed by counting gametocytes on days nine and 15 of culture and determining the infectivity of the drug-treated gametocytes to mosquitoes. Gametocytogenesis was partially inhibited by all three drugs; there were 71% of the number of gametocytes in drug-free control cultures in cultures with 3 x 10(-8) M chloroquine, 51% with 5 x 10(-8) M chloroquine, 78% with 5-7 x 10(-9) M halofantrine, and 48% with 10(-7) M pyrimethamine. Halofantrine- and pyrimethamine-treated gametocytes were found to be more infective to Anopheles stephensi than untreated controls. The three drugs were also administered to the mosquitoes, either in the first bloodmeal, which contained gametocytes from in vitro cultures, or in the second, parasite-free bloodmeal, given four days after infection. The sporontocidal activity of the drugs was evaluated by counting the number of oocysts on the midgut seven or eight days after infection, or the number of sporozoites in the salivary glands 15 days after infection. A sporontocidal effect was observed only when pyrimethamine was administered with the infective bloodmeal. Neither chloroquine nor halofantrine had any marked effect on sporogony at the concentrations tested.

  7. Ionophore-Phospholipid Interactions in Langmuir Films in Relation to Ionophore Selectivity toward Plasmodium-Infected Erythrocytes.

    PubMed

    Gumila; Miquel; Seta; Ancelin; Delort; Jeminet; Vial

    1999-10-15

    Carboxylic true ionophores were previously demonstrated to have efficient antimalarial activity against the human parasite Plasmodium falciparum, with a 50% inhibitory concentration around nM and generally high selectivity as compared to their toxic effects against mammalian cell lines. The decreased molecular packing of the erythrocyte membrane outer leaflet after malarial infection could explain the preferential ionophore interaction with infected erythrocytes. Monolayer penetration experiments using different phospholipid films showed strong incorporation of true carboxylic ionophores, from classes 1 (nigericin) and 2 (lasalocid), up to a surface pressure close to film collapse. The interaction was slightly higher with PC (phosphatidylcholine) monolayers than with monolayers composed of cholesterol-containing total lipid extracts from either malaria-infected or normal erythrocytes, and the two latter induced identical interactions with 5-bromo lasalocid. Surface pressure-area isotherms for pure ionophores on water and surface tension of ionophore aqueous solutions clearly highlighted the surface-active characteristics of these ionophores and allowed determination of their molecular area in compact monolayers. The estimated ionophore concentration in the mixed interfacial layers indicates that higher amounts (threefold more) of ionophores might be integrated in infected erythrocyte membrane due to their impaired molecular packing as compared to normal erythrocytes. This infection-enhanced penetration efficiency does not appear directly related to the change in erythrocyte membrane lipid composition, but it could be the basis of ionophore selectivity for infected erythrocytes. Copyright 1999 Academic Press.

  8. High Levels of Genetic Diversity of Plasmodium falciparum Populations in Papua New Guinea despite Variable Infection Prevalence

    PubMed Central

    Barry, Alyssa E.; Schultz, Lee; Senn, Nicholas; Nale, Joe; Kiniboro, Benson; Siba, Peter M.; Mueller, Ivo; Reeder, John C.

    2013-01-01

    High levels of genetic diversity in Plasmodium falciparum populations are an obstacle to malaria control. Here, we investigate the relationship between local variation in malaria epidemiology and parasite genetic diversity in Papua New Guinea (PNG). Cross-sectional malaria surveys were performed in 14 villages spanning four distinct malaria-endemic areas on the north coast, including one area that was sampled during the dry season. High-resolution msp2 genotyping of 2,147 blood samples identified 761 P. falciparum infections containing a total of 1,392 clones whose genotypes were used to measure genetic diversity. Considerable variability in infection prevalence and mean multiplicity of infection was observed at all of the study sites, with the area sampled during the dry season showing particularly striking local variability. Genetic diversity was strongly associated with multiplicity of infection but not with infection prevalence. In highly endemic areas, differences in infection prevalence may not translate into a decrease in parasite population diversity. PMID:23400571

  9. Potential antimalarial activity of Methyl Jasmonate and its effect on lipid profiles in Plasmodium Berghei infected mice.

    PubMed

    Oyinloye, Oladapo E; Kosoko, Ayokulehin M; Emikpe, Benjamin; Falade, Catherine O; Ademowo, Olusegun G

    2015-09-01

    The antimalarial activity and lipid profiles of Methyl Jasmonate (MJ) were investigated against established malaria infection in vivo using BALB/c mice. Arteether (AE) and chloroquine (CQ) were used as reference drugs while ethanol was used as the vehicle for drug delivery for MJ. Mice treated with 10 and 25 mg/kg MJ showed a remarkable reduction in percentage parasitemia by 68.3% and 78.2% on day 10(post treatment) respectively while 45.4% and 87.2% reduction in percentage parasitemia were observed in the group treated with 50 mg/kg on day 3 and 10 (post treatment) respectively. The highest mean survival time was observed in CQ followed by AE and MJ in dose-dependent manner. A progressive decrease in packed cell volume (PCV) was observed in infected untreated mice which led to the death of all the mice by day 9 (post treatment). Infected mice treated with MJ showed reduced level of HDL and LDL compared with infected untreated group. As the dose of MJ increased in infected mice cholesterol levels increased while there was reduction in triglyceride. Overall there was marked decrease in parasitemia in Plasmodium berghei infected mice treated with graded doses of MJ but appears to have reduced antimalarial activity compared with CQ and AE.

  10. Specific antibody responses against membrane proteins of erythrocytes infected by Plasmodium falciparum of individuals briefly exposed to malaria

    PubMed Central

    2010-01-01

    Background Plasmodium falciparum infections could lead to severe malaria, principally in non-immune individuals as children and travellers from countries exempted of malaria. Severe malaria is often associated with the sequestration of P. falciparum-infected erythrocytes in deep micro-vascular beds via interactions between host endothelial receptors and parasite ligands expressed on the surface of the infected erythrocyte. Although, serological responses from individuals living in endemic areas against proteins expressed at surface of the infected erythrocyte have been largely studied, seldom data are available about the specific targets of antibody response from travellers. Methods In order to characterize antigens recognized by traveller sera, a comparison of IgG immune response against membrane protein extracts from uninfected and P. falciparum-infected red blood cells (iRBC), using immunoblots, was performed between non exposed individuals (n = 31) and briefly exposed individuals (BEI) (n = 38) to malaria transmission. Results Immune profile analysis indicated that eight protein bands from iRBC were significantly detected more frequently in the BEI group. Some of these antigenic proteins were identified by an original immuno-proteomic approach. Conclusion Collectively, these data may be useful to characterize the singular serological immune response against a primary malaria infection in individuals briefly exposed to transmission. PMID:20932351

  11. Electrical Conductivity in a Mixed-Species Biofilm

    PubMed Central

    Lau, Joanne; Nevin, Kelly P.; Franks, Ashley E.; Tuominen, Mark T.; Lovley, Derek R.

    2012-01-01

    Geobacter sulfurreducens can form electrically conductive biofilms, but the potential for conductivity through mixed-species biofilms has not been examined. A current-producing biofilm grown from a wastewater sludge inoculum was highly conductive with low charge transfer resistance even though microorganisms other than Geobacteraceae accounted for nearly half the microbial community. PMID:22706052

  12. Two-Color Flow Cytometric Analysis of Intraerythrocytic Malaria Parasite DNA and Surface Membrane-Associated Antigen in Erythrocytes Infected with Plasmodium falciparum

    DTIC Science & Technology

    1993-01-01

    Antigen in Erythrocytes Infected With Plasmodium falciparum 1 Kovit Pattanapanyasat,2 Rachanee Udomsangpetch, and H. Kyle Webster The Thalassemia Center... Thalassemia Center, Division of Hematology., Siriraj Hospital, 15). Identification of conserved epitopes has important Bangkok 10700. Thailan 93-10832 93 5 4

  13. Evaluation of the 4-pyridinemethanol WR 180,409 (enpiroline) in the treatment of induced Plasmodium falciparum infections in healthy, non-immune subjects.

    PubMed

    Cosgriff, T M; Boudreau, E F; Pamplin, C L; Berman, J D; Shmuklarsky, M J; Canfield, C J

    1984-09-01

    WR 180,409 (enpiroline) was administered to 22 non-immune subjects infected with the multi-drug resistant Vietnam Smith isolate of Plasmodium falciparum. It was curative in single day treatment regimens with a minimum curative dose of approximately 10 mg/kg body weight. At this dose level it was well tolerated and produced rapid clearance of parasitemia in every case.

  14. Plasmodium falciparum infection in febrile Congolese children: prevalence of clinical malaria 10 years after introduction of artemisinin-combination therapies.

    PubMed

    Etoka-Beka, Mandingha Kosso; Ntoumi, Francine; Kombo, Michael; Deibert, Julia; Poulain, Pierre; Vouvoungui, Christevy; Kobawila, Simon Charles; Koukouikila-Koussounda, Felix

    2016-12-01

    To investigate the proportion of malaria infection in febrile children consulting a paediatric hospital in Brazzaville, to determine the prevalence of submicroscopic malaria infection, to characterise Plasmodium falciparum infection and compare the prevalence of uncomplicated P. falciparum malaria according to haemoglobin profiles. Blood samples were collected from children aged <10 years with an axillary temperature ≥37.5 °C consulting the paediatric ward of Marien Ngouabi Hospital in Brazzaville. Parasite density was determined and all samples were screened for P. falciparum by nested polymerase chain reaction (PCR) using the P. falciparum msp-2 marker to detect submicroscopic infections and characterise P. falciparum infection. Sickle cell trait was screened by PCR. A total of 229 children with fever were recruited, of whom 10% were diagnosed with uncomplicated malaria and 21% with submicroscopic infection. The mean parasite density in children with uncomplicated malaria was 42 824 parasites/μl of blood. The multiplicity of infection (MOI) was 1.59 in children with uncomplicated malaria and 1.69 in children with submicroscopic infection. The mean haemoglobin level was 10.1 ± 1.7 for children with uncomplicated malaria and 12.0 ± 8.6 for children with submicroscopic infection. About 13% of the children harboured the sickle cell trait (HbAS); the rest had normal haemoglobin (HbAA). No difference in prevalence of uncomplicated malaria and submicroscopic infection, parasite density, haemoglobin level, MOI and P. falciparum genetic diversity was observed according to haemoglobin type. The low prevalence of uncomplicated malaria in febrile Congolese children indicates the necessity to investigate carefully other causes of fever. © 2016 John Wiley & Sons Ltd.

  15. Molecular evidence of Plasmodium vivax mono and mixed malaria parasite infections in Duffy-negative native Cameroonians.

    PubMed

    Ngassa Mbenda, Huguette Gaelle; Das, Aparup

    2014-01-01

    The malaria parasite Plasmodium vivax is known to be majorly endemic to Asian and Latin American countries with no or very few reports of Africans infected with this parasite. Since the human Duffy antigens act as receptors for P. vivax to invade human RBCs and Africans are generally Duffy-negative, non-endemicity of P. vivax in Africa has been attributed to this fact. However, recent reports describing P. vivax infections in Duffy-negative Africans from West and Central parts of Africa have been surfaced including a recent report on P. vivax infection in native Cameroonians. In order to know if Cameroonians living in the southern regions are also susceptible to P. vivax infection, we collected finger-prick blood samples from 485 malarial symptomatic patients in five locations and followed PCR diagnostic assays with DNA sequencing of the 18S ribosomal RNA gene. Out of the 201 malaria positive cases detected, 193 were pure P. falciparum, six pure P. vivax and two mixed parasite infections (P. falciparum + P. vivax). The eight P. vivax infected samples (six single + two mixed) were further subjected to DNA sequencing of the P. vivax multidrug resistance 1 (pvmdr1) and the P.vivax circumsporozoite (pvcsp) genes. Alignment of the eight Cameroonian pvmdr1 sequences with the reference sequence showed high sequence similarities, reconfirming P. vivax infection in all the eight patients. DNA sequencing of the pvcsp gene indicated all the eight P. vivax to be of VK247 type. Interestingly, DNA sequencing of a part of the human Duffy gene covering the promoter region in the eight P. vivax-infected Cameroonians to identify the T-33C mutation revealed all these patients as Duffy-negative. The results provide evidence of single P. vivax as well as mixed malaria parasite infection in native Cameroonians and add knowledge to the growing evidences of P. vivax infection in Duffy-negative Africans.

  16. Plasmodium falciparum multiple infections in Mozambique, its relation to other malariological indices and to prospective risk of malaria morbidity.

    PubMed

    Mayor, Alfredo; Saute, Francisco; Aponte, John J; Almeda, Jesús; Gómez-Olivé, F Xavier; Dgedge, Martinho; Alonso, Pedro L

    2003-01-01

    We describe the frequency of Plasmodium falciparum clones infecting individuals living in a rural area of southern Mozambique and analyse the relationship between multiplicity of infection, age and other malariometric indices, including prospective risk of clinical malaria. The genotyping was based on the use of restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR) analysis of P. falciparum merozoite surface protein 2 (msp2). We analysed 826 samples collected during five cross-sectional surveys from residents of Manhiça ranging in age from 4 months to 83 years. We also determined the multiplicity of infection in samples obtained from 6-month-old infants (n = 79) and children <10 years (n = 158) who were then treated and followed prospectively for 1 year or 75 weeks, respectively. Multiplicity of infection did not vary significantly during the first year of life, but increased thereafter, and decreased during adulthood to the levels found in infants. With increasing multiplicity of infection, there was a statistically significant decrease in the risk of submicroscopic infections. There was also a significant correlation between multiplicity of infection and parasite density in infants, children <4 years of age and adults, suggesting that high densities increase the probability of discriminating more clones in complex infections. We found that the relationship between multiple infections and malaria morbidity is age-dependent. In infants, the risk of subsequent episodes of clinical malaria was related to the parasite density but not to baseline multiplicity of infection. In older children, however, the more clones a child carried, the more likely they were to have a clinical malaria episode, and this was true after adjusting for parasite densities. This change in the association between multiplicity and risk of clinical malaria may indicate a shift in the host response to P. falciparum.

  17. Plasmodium falciparum Infection Status among Children with Schistosoma in Sub-Saharan Africa: A Systematic Review and Meta-analysis

    PubMed Central

    Degarege, Abraham; Degarege, Dawit; Veledar, Emir; Erko, Berhanu; Nacher, Mathieu; Beck-Sague, Consuelo M.; Madhivanan, Purnima

    2016-01-01

    Background It has been suggested that Schistosoma infection may be associated with Plasmodium falciparum infection or related reduction in haemoglobin level, but the nature of this interaction remains unclear. This systematic review synthesized evidence on the relationship of S. haematobium or S. mansoni infection with the occurrence of P. falciparum malaria, Plasmodium density and related reduction in haemoglobin level among children in sub-Saharan Africa (SSA). Methodology/Principal findings A systematic review in according with PRISMA guidelines was conducted. All published articles available in PubMed, Embase, Cochrane library and CINAHL databases before May 20, 2015 were searched without any limits. Two reviewers independently screened, reviewed and assessed all the studies. Cochrane Q and Moran’s I2 were used to assess heterogeneity and the Egger test was used to examine publication bias. The summary odds ratio (OR), summary regression co-efficient (β) and 95% confidence intervals (CI) were estimated using a random-effects model. Out of 2,920 citations screened, 12 articles (five cross-sectional, seven prospective cohort) were eligible to be included in the systematic review and 11 in the meta-analysis. The 12 studies involved 9,337 children in eight SSA countries. Eight studies compared the odds of asymptomatic/uncomplicated P. falciparum infection, two studies compared the incidence of uncomplicated P. falciparum infection, six studies compared P. falciparum density and four studies compared mean haemoglobin level between children infected and uninfected with S. haematobium or S. mansoni. Summary estimates of the eight studies based on 6,018 children showed a higher odds of asymptomatic/uncomplicated P. falciparum infection in children infected with S. mansoni or S. haematobium compared to those uninfected with Schistosoma (summary OR: 1.82; 95%CI: 1.41, 2.35; I2: 52.3%). The increase in odds of asymptomatic/uncomplicated P. falciparum infection among

  18. Infection of Laboratory-Colonized Anopheles darlingi Mosquitoes by Plasmodium vivax

    PubMed Central

    Moreno, Marta; Tong, Carlos; Guzmán, Mitchel; Chuquiyauri, Raul; Llanos-Cuentas, Alejandro; Rodriguez, Hugo; Gamboa, Dionicia; Meister, Stephan; Winzeler, Elizabeth A.; Maguina, Paula; Conn, Jan E.; Vinetz, Joseph M.

    2014-01-01

    Anopheles darlingi Root is the most important malaria vector in the Amazonia region of South America. However, continuous propagation of An. darlingi in the laboratory has been elusive, limiting entomological, genetic/genomic, and vector–pathogen interaction studies of this mosquito species. Here, we report the establishment of an An. darlingi colony derived from wild-caught mosquitoes obtained in the northeastern Peruvian Amazon region of Iquitos in the Loreto Department. We show that the numbers of eggs, larvae, pupae, and adults continue to rise at least to the F6 generation. Comparison of feeding Plasmodium vivax ex vivo of F4 and F5 to F1 generation mosquitoes showed the comparable presence of oocysts and sporozoites, with numbers that corresponded to blood-stage asexual parasitemia and gametocytemia, confirming P. vivax vectorial capacity in the colonized mosquitoes. These results provide new avenues for research on An. darlingi biology and study of An. darlingi–Plasmodium interactions. PMID:24534811

  19. The Complexity of Plasmodium Falciparum Infections in Children in Western Kenya

    DTIC Science & Technology

    2006-01-01

    fuse and form short-lived diploid zygotes. These undergo meiotic division, creating haploid cells that after further development and asexual...the common feature of being single copy in the haploid blood stages of the parasite life cycle and having highly variable regions with insertion...and evolution of the malaria vaccine candidate merozoite surface protein-1 (MSP-1) of Plasmodium falciparum. Gene 304: 65-75. 44. Ferreira MU, Liu

  20. In vitro infectivity of