Browsing by Author "Wellawatta, C."

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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.
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    Hepatitis B virus (HBV) genotypes in a group of Sri Lankan patients with chronic infection
    (Malaysian Society of Parasitology and Tropical Medicine, 2011) Manamperi, A.; Gunawardene, N.S.; Wellawatta, C.; Abeyewickreme, W.; de Silva, H.J.
    Hepatitis B infection causes a wide spectrum of liver diseases. Previous analyses of hepatitis B virus (HBV) genome have revealed eight HBV genotypes (A-H), with distinct geographical distribution worldwide. The epidemiology of HBV genotypes and their implications for natural history of disease progression and response to anti viral therapy have been increasingly recognized. This study was undertaken to determine the HBV genotypes in a group of Sri Lankan patients with chronic infection who presented for investigation prior to treatment. Genotypes were determined (2007-2009) in 25 patients with evidence of chronic HBV infection. A genotyping system based on multiplex-nested PCR using type-specific primers was employed in assigning genotypes A through F. Genotypes G and H were not determined. Among the 25 patients tested, genotypes B [9 (36%)], C [4 (16%)], D [3 (12%)], A [2 (8%)] and E [1 (4%)] were detected. There was a relatively high prevalence of mixed infections with genotypes B+C (3), A+D (1), and B+D (2), which overall constituted 24% of patients. Although this is a non-representative sample, HBV infections among this group of Sri Lankan patients were predominantly genotypes B, C and D.