Viengngeun Bounkeua

University of California, San Diego, San Diego, CA, United States

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Publications (4)6.81 Total impact

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    ABSTRACT: Previous studies of Plasmodium vivax transmission to Anopheles spp. mosquitoes have not been able to predict mosquito infectivity on the basis of microscopic or molecular quantification of parasites (total parasites in the sample or total number of gametocytes) in infected blood. Two methods for production of P. vivax ookinete cultures in vitro, with yields of 10(6) macrogametocytes, 10(4) zygotes, and 10(3) ookinetes, respectively, per 10 mL of P. vivax-infected patient blood with approximately 0.01% parasitemia, were used to study P. vivax sexual stage development. The quantity of gametocytes, determined by counting Giemsa-stained blood smears, and quantity and type of gametocyte as determined by quantitative reverse transcriptase-polymerase chain reaction for Pvalpha tubulin II and macrogametocyte-specific pvg377 did not predict ookinete yield. Factors that affect the efficiency of in vitro P. vivax ookinete transformation remain poorly understood.
    The American journal of tropical medicine and hygiene 08/2011; 85(2):207-13. · 2.53 Impact Factor
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    ABSTRACT: Previous studies of Plasmodium vivax transmission to Anopheles spp. mosquitoes have not been able to predict mosquito infectivity on the basis of microscopic or molecular quantification of parasites (total parasites in the simple or total number of gametocytes) in infected blood. Two methods for production of P. vivax ookinete cultures in vitro , with yields of 10*6 macrogametocytes, 10*4 zygotes, and 10*3 ookinetes, respectively, per 10 mL of P. vivax- infected patient blood with approximately 0.01% parasitemia, were used to study P. vivax sexual stage development. The quantity of gametocytes determined by counting Giemsa-stained blood smears, and quantity and type of gametocyte as determined by quantitative reverse transcriptase–polymerase chain reaction for Pvalpha tubulin II and macrogametocyte-specific pvg377 did not predict ookinete yield. Factors that affect the efficiency of in vitro P. vivax ookinete transformation remain poorly understood.
    The Journal of tropical medicine and hygiene 05/2011; 85(2):207-213.
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    Viengngeun Bounkeua, Fengwu Li, Joseph M Vinetz
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    ABSTRACT: Plasmodium transmission from the human host to the mosquito depends on the ability of gametocytes to differentiate into ookinetes, the invasive form of the parasite that invades and establishes infection in the mosquito midgut. The biology of P. falciparum ookinetes is poorly understood, because sufficient quantities of this stage of this parasite species have not been obtained for detailed study. This report details methods to optimize production of P. falciparum sexual stage parasites, including ookinetes. Flow cytometric sorting was used to separate diploid/tetraploid zygotes and ookinetes from haploid gametetocytes and unfertilized gametes based on DNA content. Consistent production of 10(6)-10(7) P. falciparum ookinetes per 10 mL culture was observed, with ookinete transformation present in 10-40% of all parasite forms. Transmission electron micrographs of cultured parasites confirmed ookinete development.
    The American journal of tropical medicine and hygiene 12/2010; 83(6):1187-94. · 2.53 Impact Factor
  • V. Bounkeua, F. Li, K. Patra, J. M. Vinetz
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    ABSTRACT: An abstract is unavailable. This article is available as HTML full text and PDF.
    Journal of Investigative Medicine 12/2006; 55(1):S123. · 1.75 Impact Factor