Medicine
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This repository contains the published and unpublished research of the Faculty of Medicine by the staff members of the faculty
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Item Filarial dance sign (FDS) in patients with lymphatic filariasis(Sri Lanka Medical Association, 2008) Premaratna, R.; Chandrasena, T.G.A.N.; Gunawardena, N.K.; de Silva, N.R.; de Silva, H.J.BACKGROUND: Lymphatic filariasis causes acute lymphangitis, epididymo-orchi tis hydrocoele, lymphoedema and nocturnal cough. Diagnostic tests based on circulating filarial antigens (CFA) and filarial antibodies (FAT) have limitations in confirming symptomatic filariasis. Filaria dance sign (FDS) demonstrated using soft tissue ultrasonography permits identification of live adult filarial worms in-situ. OBJECTIVES: FDS, CFA and FAT status in patients with clinical features suggestive of lymphatic filariasis. DESIGN, SETTING AND METHODS: Adult males with symptoms suggestive of filarial infection were subjected to scrotal scans using a Toshiba 7.5MHz soft tissue transducer to elicit the FDS. All subjects were screened for CFA and FAT by NOW® Filariasis (Binax Inc. USA) and On-Site Filariasis IgG/IgM Rapid Test (Biotech. Inc. USA) respectively. RESULTS: Forty eight males, mean age 48.5 yrs (SD: 15.2), presenting with lymphoedema of lower limbs (LL, n=29), lower limb cellulitis with lymphangitis (LCL, n=7), hydrocoele (H, n=7), acute epididymo-orchitis (A.EO, n=3), hydrocoele with lower limb lymphoedema (HLL, n=2) and nocturnal-cough (NC, n=9) were studied. FDS was demonstrated in 38(79%); 7 patients with H, 16 with LL, 5 with LCL, AEO 1 and 9 with NC. Six of 41 (14.6%) patients tested for filarial antibodies were positive for filaria-specific IgG; 2 of them were also positive for filaria-specific IgM. Two of the six IgG positives were negative for FDS. The 4 IgG and FDS positives had LCL (n=2), H (n=l) and AEO (n=l). All were CFA negative CONCLUSIONS: Although time consuming, demonstration of FDS by soft tissue ultrasonography can be useful in confirming symptomatic filariasis compared to FAT and CFA.Item Effect of mass chemotherapy for filariasis control on soil-transmitted helminth infection in Western Province of Sri Lanka(The Royal Society of Tropical Medicine and Hygiene, 2007) Gunawardena, N.K.; Amarasekera, N.D.D.M.; Pathmeswaran, A.; de Silva, N.R.In July 2006, Sri Lanka completed five rounds of annual mass drug administration (MDA) with diethylcarbamazine citrate and albendazole as part of its national programme for elimination of lymphatic filariasis. Albendazole is also highly effective against soil-transmitted helminths (STH). This study was carried out to assess the impact of repeated annual MDA on STH infections in the Western Province of Sri Lanka, an area that is co-endemic for lymphatic filariasis and STH. A total of 17 schools in the Western Province were selected because they were included in a national survey of the health of school children in Grade 5 in 2003, when one round of MDA had been completed. Faecal samples were obtained again in 2006 (after five rounds of MDA), from one randomly selected class of Grade 5 students in the same schools. In both surveys, faecal samples were examined using the modified Kato-Katz technique. The prevalence and intensity of roundworm, whipworm and hookworm infections in 2003 and 2006 were compared using chi-square or Z-test for a difference between two percentages. Faecal samples from 255 children were examined in 2003; 448 were examined in 2006. Roundworm prevalence was marginally lower in 2006 (4.0%) than in 2003 (4.7%), as was hookworm (0.2% vs 0.4%) whereas whipworm prevalence was higher (13.8% vs 9.4%). Mean egg counts for all three infections were marginally higher in 2006. However, none of these differences were statistically significant. Compliance with MDA in 2006, as reported by the school children examined, was only 59%. These results indicate that four annual roundsof MDA with diethylcarbamazine and citrate and albendazole had virtually no impact on STH infections in the study area. It is likely that inclusion of of albendazole in MDA for lymphatic filariasis does not have much impact on STH infections in areas of low endemicity, unless very high coverage rates are achieved.Item Integrated school-based surveillance for soil-transmitted helminth infections and for lymphatic filariasis in Gampaha district, Sri Lanka(American Society of Tropical Medicine and Hygiene, 2013) Gunawardena, N.K.; Gunawardena, S.; Kahathuduwa, G.; Karunaweera, N.D.; de Silva, N.R.; Ranasinghe, U.S.; Rao, R. U.; Rebollo, M.; Weil, G. J.The Sri Lankan Anti-Filariasis Campaign (AFC) conducted 5 rounds of annual mass drug administration (MDA) with albendazole and DEC in 2002-2006 in 8 districts that were endemic for lymphatic filariasis (LF) (target population approximately 10 million). AFC conducted transmission assessment surveys (TAS) in 2012, about 6 years after the last round of MDA. This study explored the practicality of integrating surveillance for soil transmitted helminth (STH) infections with TAS for LF in Gampaha district (population 2.3 million). The district was divided into two Evaluation Units (EUs), coastal and inland. Each TAS tested 1st and 2nd grade school children drawn from 30 randomly selected schools (N=1,462 inland, 1,642 coastal). Tests included the ICT card test for filarial antigenemia (performed by AFC personnel) and the Kato-Katz test for detection of STH ova (performed by university personnel). ICT rates were 0% and 0.1% (0.01-0.3% CI) in the inland and coastal EUs, respectively. These results suggest that LF transmission rates are very low in Gampaha District. The STH survey was conducted at the same time as the TAS in the inland EU (955 stools from 1,211 children) and several weeks after the TAS in the coastal EU (927 stools from 1,586 children). STH infection rates and stool sample participation rates were 0.8% and 79% in the inland EU and 2.8% and 58% in the coastal EU. Most of the STH infections detected were lowintensityTrichuris (present in 73% of positive stools). The low STH rates are probably due to the country’s national school deworming program (mebendazole in grades 1, 4, and 7) and relatively good sanitation in Gampaha district. The cost for STH testing was approximately $5,000 per EU. These results suggest that it is feasible for national NTD programs to integrate school based surveillance for STH and LF. Further work is needed to streamline procedures and to determine optimal sampling strategies for STH surveys, because these may not require as many samples or sampling sites as TAS.Item Night blood survey of a selected high-risk population for lymphatic filariasis(Sri Lanka Association for the Advancement of Science, 2007) Wijegunawardana, N.D.A.D.; Gunawardene, Y.I.N.S.; Abeyewickreme, W.; Gunawardena, N.K.; Hapuarachchi, H.A.C.; Abeysundara, S.Human infection with Wuchereria bancrofti causes a disabling parasitic disease known as lymphatic filariasis, which is a major public health and socio-economic problem in many parts of the world. Little is known about the prevalence of filariasis among high-risk populations for filariasis. Objective of this study was to determine such prevalence of lymphatic filariasis among Mahara prison inmates whom the Anti Filaria Campaign (AFC) has identified as a high-risk group. All inmates of Mahara Prison were screened for Microfilariae (Mf) except those in special cells, by night blood film microscopy to determine the prevalence of infection from February to May 2007. All inmates were males of greater than 15 years. Of the 423 inmates screened, 15 were positive for Mf, giving a Mf positive rate of 3.55% in the study population and a mean Mf density of 5 Mf/60 æl blood, ranging between 4 to 9.2 Mf /60 æl of blood with a standard deviation of 2.49. The highest number of infected inmates was residents of Colombo and Gampaha districts where transmission is currently taking place. This is one of the few studies undertaken to date to determine the prevalence of bancroftian filariasis among inmates of a prison, a neglected population in Sri Lanka. This study indicates that the Mf rate of bancroftian filariasis in this study population is far greater than the 0.18% currently reported in the country. Therefore, an intensive programme is recommended to contain the spread of infection within this study population. For this, a proper screening programme combined with antifilarial treatment and vector control programme is urgently required. Acknowledgements: Authors wish to acknowledge the financial assistance received from WHO/SEARO/TDR (grant no. SN 1152) and University of Kelaniya (Research grant no. RP/03/04/06/01/2006). Authors wish to thank Dr. Ravi Mudaliage, Senior Medical Officer, Prison's Hospital, Mahara, Ragama for his support and encouragement during field study activities. Authors also wish to thank Mr. M. Y. D. Dayanath, Ms. N.M. Ashoka Malanie, Mr. M.I.M.Peris, Mr. Y.L.Rassapana and other staff members of the Molecular Medicine Unit and Department of Parasitology, Faculty of Medicne, University of Kelaniya, Ragama for their assistanceItem Comparison of five DNA extraction methods from human blood for the detection of Wuchereria bancrofti by polymerase chain reaction assays(Sri Lanka Association for the Advancement of Science, 2008) Wijegunawardana, N.D.A.D.; Gunawardene, Y.I.N.S.; Manamperi, A.; Hapuarachchi, H.A.C.; Gunawardena, N.K.; Abeysundara, S.; Abeyewickreme, W.Introduction: Lymphatic filariasis (Lf) is the second most common vector-borne disease globally. Approximately 90% of global burden of Lf is caused by Wuchereria bancrofti. W. bancrofti is routinely diagnosed by morphological identification of microfilariae (Mf) by microscopy which is a labour intense, low sensitive and time consuming method. Detection of W. bancrofti Deoxyribonucleic acid (DNA) using polymerase chain reaction (PCR) technique has become popular today, because of its high sensitivity and specificity. The overall success of the PCR strategy in detecting a filarial parasite in human blood varies between sample preparation methods. The objective of this study was to compare five DNA extraction methods (Lysis + centrifugation, Chelex method, Mf pellet method, Q1Aamp DNA Mini Kit commercial system, and Phenol-chloroform) with regard to duration of completion, labor involvement and PCR analytical sensitivity in-relation to DNA quality and quantity for the detection of W. bancrofti in human blood. Five blood samples positive for mf of W. bancrofti were tested for each DNA extraction method and were compared with respect to the sensitivity, time and quality/quantity of DNA and also by PCR analysis. Of the 5 methods tested, Mf pellet method was found to be the most simple and effective technique for the isolation of W. bancrofti Mf in human blood. This method was quick (15 min to complete), simple (5 min of manual labor), and very economical. It does not require any organic solvents, and the entire extraction procedure uses only two steps requiring supernatant transfer between tubes, hence minimizing the possibility of cross-contamination. Moreover, the PCR analytical sensitivity of the Mf pellet method was comparable to that of the commercial kit used. No PCR inhibitors were detected, independently of Mf count in the blood. Same method (optimal DNA extraction method) can be also used for the detection of parasite DNA from the field collected Mf positive mosquitoes using a PCR. Therefore, we recommend the Mf pellet method for processing large numbers of blood samples in community surveys aimed at determining the prevalence of W. bancrofti infection.