Browsing by Author "Wickremasinghe, R*."

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    Cross-sectional study to assess risk factorsfor leishmaniasis in an endemic region in Sri Lanka
    (American Society of Tropical Medicine and Hygiene, 2013) Ranasinghe, S.; Wickremasinghe, R*.; Munasinghe, A.; Hulangamuwa, S.; Sivanantharajah, S.; Seneviratne, K.; Bandara, S.; Athauda, I.; Navaratne, C.; Silva, O.; Wackwella, H.; Matlashewski, G.; Wickremasinghe, R.
    Sri Lanka reports significantly more cutaneous leishmaniasis (CL) cases than visceral leishmaniasis (VL) cases, both of which are caused by Leishmania donovani MON-37. A cross-sectional study conducted in an area with a high prevalence of CL prevalent included 954 participants of an estimated population of 61,674 to estimate the number of CL cases, ascertain whether there is a pool of asymptomatic VL cases, and identify risk factors for transmission. A total of 31 cases of CL were identified, of whom 21 were previously diagnosed and 10 were new cases. Using rK39 rapid diagnostic test to detect antibodies against Leishmania spp., we found that only one person was seropositive but did not have clinical symptoms of CL or VL, which indicated low transmission of VL in this area. χ(2) test, independent sample t-test, and multivariate analysis of socio demographic and spatial distribution of environmental risk factors showed that living near paddy fields is associated with increased risk for transmission of CL (P ≤ 0.01).
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    Genetic Polymorphism in Pvmsp-3a. and Pvcs genes in Plasmodium vivax infections in Sri Lanka
    (Sri Lanka College of Microbiologists, 2008) Manamperi, A.; Fernando, D.; Mahawithanage, S.; Wickremasinghe, R*.; Bandara, A.; Wellawatta, C.; Hapuarachchi, C.; Abeyewickreme, W.; Wickremasinghe, R.
    INTRODUCTION: Plasmodim vivax malaria accounts for about 70% of all malaria infections in Sri Lanka. There is limited information on the genetic heterogeneity of P. vivax parasites in endemic areas of the country. OBJECTIVE: The objective of this study was to assess the potential of two P. vivax genes, Pvmsp-3v. and Pvcs. as genetic markers for their use in genotyping parasites collected from the field. METHOD: DNA was extracted from 12 Geimsa-stained P. vivax positive slides by phenol/chloroform method. A nested polymerase chain reaction (PCR) approach was adopted for both Pvmsp-3a and Pvcs genes. RFLP analysis ofPvmsp-la nested PCR products was carried out with Hha\ restriction enzyme. RESULTS AND DISCUSSION: Nested amplification of the marker genes resulted in 4 size variants for Pvcs (~ 600-750 bp) and 2 size variants for Pvmsp-3a (1.9 kb and 1.1 kb). Further, all PCR-RFLP products of Pvmsp-3a. Gene showed a major size polymorphism. Three samples showed evidence of infections with mixed genotypes and there was also evidence to identify a relapse infection. Analysis of these two genetic markers revealed 11 distinguishable variant types: 4 for Pvcs and 7 for Pvmsp-3a. CONCLUSIONS: The observed PCR and PCR-RFLP profiles of the Pvcs and Pvmsp-3& genes demonstrate that the P. vivax parasites in Sri Lanka were highly diverse despite the prevailing low transmission levels. It could be concluded that these two genes in combination could be considered suitable genetic markers to analyze P. vivax parasite dynamics in Sri Lanka.