Journal/Magazine Articles
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This collection contains original research articles, review articles and case reports published in local and international peer reviewed journals by the staff members of the Faculty of Medicine
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Item Integrated school-based surveillance for soil-transmitted helminth infections and lymphatic filariasis in Gampaha district, Sri Lanka(American Society of Tropical Medicine and Hygiene, 2014) Gunawardena, S.; Gunawardena, N.K.; Kahathuduwa, G.; Karunaweera, ND.; de Silva, N.R.; Ranasinghe, U.B.; Samarasekara, S.D.; Nagodavithana, K.C.; Rao, R.U.; Rebollo, M.P.; Weil, G.J.We explored the practicality of integrating surveillance for soil-transmitted helminthiasis (STH, assessed by Kato-Katz) with transmission assessment surveys for lymphatic filariasis (LF) in two evaluation units (EUs) in Gampaha district, Sri Lanka (population 2.3 million). The surveys were performed 6 years after five annual rounds of mass drug administration with diethylcarbamazine and albendazole. Each transmission assessment survey tested children (N = 1,462 inland EU; 1,642 coastal EU) sampled from 30 primary schools. Low filarial antigenemia rates (0% and 0.1% for the inland and coastal EUs) suggest that LF transmission is very low in this district. The STH rates and stool sample participation rates were 0.8% and 61% (inland) and 2.8% and 58% (coastal). Most STH detected were low or moderate intensity Trichuris trichiura infections. The added cost of including STH testing was ∼$5,000 per EU. These results suggest that it is feasible to integrate school-based surveillance for STH and LFItem Effect of repeated mass chemotherapy for filariasis control on soil-transmitted helminth infections in Sri Lanka(Sri Lanka Medical Association, 2008) Gunawardena, N.K.; Amarasekera, N.D.D.M.; Pathmeswaran, A.; de Silva, N.R.BACKGROUND: In July 2006 Sri Lanka completed 5 rounds of annual mass drug administration (MDA) with diethylcarbamazine citrate (DEC) and albendazole as part of its national programme for elimination of lymphatic filariasis (LF). Albendazole is highly effective against soil-transmitted helminths (STH). This study was carried out to assess the effect of repeated annual MDA on STH infections in the Western Province of Sri Lanka, an area co-endemic for LF and STH. METHODS: Faecal samples were obtained (during August-September 2006), from grade 5 students in 17 schools in the Western Province that were included in a national survey of schoolchildren's health in 2003, and examined using the modified Kato-Katz technique. The prevalence and intensity of roundworm, whipworm and hookworm infections in 2003 and 2006 were compared. RESULTS: 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%). These differences as well as that between the geometric mean egg counts were not statistically significant. Compliance with MDA in 2006, as reported by the schoolchildren examined, was only 59%. CONCLUSIONS: Four annual rounds of MDA with DEC and albendazole had virtually no effect on STH infections in the study area.Item Social mobilization, drug coverage and compliance and adverse reactions in a Mass Drug Administration (MDA) Programme for the elimination of Lymphatic Filariasis in Sri Lanka(BioMed Central, 2007) Weerasooriya, M.V.; Yahathugoda, T.C.; Wickremasinghe, D.; Gunawardena, N.K.; Dharmadasa, R.A.; Vidanapathirana, K.K.; Weerasekara, S.H.; Samarawickrema, W.A.BACKGROUND: In Sri Lanka filariasis is endemic in Southern, Western and North Western provinces covering eight districts designated as implementation units in the Programme for the Elimination of Lymphatic Filariasis (PELF). Despite control activities over sixty years including multidose diethylcarbamazine, 6 mg/kg treatment microfilaria rates had persisted at low levels. Following systematic social mobilisation the first MDA with DEC albendazole combination was conducted in 2002. METHODS: We investigated the extent social mobilisation had reached the people, their drug compliance and adverse reactions. Three localities were selected from each district to pick target population samples for pre-tested questionnaire. Three teams each with six people visited one district each day. One team worked from three starting points in one locality. A member applied eight part questionnaire to one family member totalling 150-160 people from one locality. Questions included social mobilisation, drug compliance and adverse reactions. RESULTS: Information was disseminated by television, radio, banners and leaflets, to a lesser extent by people. Information reached more people in the periphery than in Colombo. 35.2% from Colombo municipality were unaware of the MDA. Drug coverage was 79.6%, home delivery 71.7% and delivery centres 7.9%. 35.6% in Colombo district and 53.4% from Colombo municipality did not receive drugs. Drugs were consumed by 71.4%. 28.6% who did not comply included 20.4% who did not receive them. 91.4% showed no adverse reactions, 7.5% were mild, 1.1% recovered with home remedies. CONCLUSION: Drug compliance showed significant positive correlation with awareness of the MDA. Door to door delivery was more successful than delivery from centres. More delivery centres conveniently located would have rectified this disparity. Poor awareness and compliance in Colombo and urban areas could be rectified with separate strategy for urban areas. More time for MDA and trained adequate manpower would ensure coverage to achieve elimination.Item Human infection with Wuchereria bancrofti in Matara, Sri Lanka: the use, in parallel, of an ELISA to detect filaria-specific IgG4 in urine and of ICT card tests to detect filarial antigen in whole blood(Academic Press, 2003) Weerasooriya, M.V.; Itoh, M.; Mudalige, M.P.; Qiu, X.G.; Kimura, E.; Gunawardena, N.K.; Fujimaki, Y.The ICT card test to detect circulating filarial antigen and an ELISA that detects filaria-specific urinary IgG(4) were each used to screen 473 subjects from a community in Sri Lanka where Wuchereria bancrofti is endemic. When the ICT test was used as the gold standard, the ELISA was found to have a sensitivity of 91.2%. However, far more of the subjects were found ELISA-positive than ICT-positive (76.5% v. 31.1%). The youngest children studied (aged 1-10 years) were similar to the adult subjects in terms of the prevalence of antigenaemia (33.8%) and the prevalence (72.1%) and concentration of filaria-specific IgG(4) in their urine. Therefore, especially as urine samples are easier, less painful and safer to collect than blood samples, the ELISA may be particularly useful to screen very young and school-age children, to estimate current levels of transmission in a particular area.Item Prevalence and intensity of Wuchereria bancrofti antigenaemia in Sri Lanka by Og4C3 ELISA using filter paper-absorbed whole blood(Oxford University Press, 2002) Weerasooriya, M.V.; Gunawardena, N.K.; Itoh, M.; Qiu, X.G.; Kimura, E.In Sri Lanka 2741 people from Matara, an endemic area for Wuchereria bancrofti, were examined in 1996/97 for microfilariae by 60-microL blood smear and for circulating filarial antigens by Og4C3 ELISA using filter paper-absorbed whole blood. The overall prevalence of microfilaraemia was 3.4%, and that of antigenaemia 14.4%. The prevalence of antigen-positive and microfilaria-negative people was 11.3%. Analysed by age-group,antigenaemia prevalence was similar in all groups, and the average number of antigen units was already very high in the age-group < 10 years, indicating that the infection started in early childhood. Among those who were antigen positive, the microfilaria prevalence was lower in females than in males. Diethylcarbamazine treatment eliminated microfilariae in 78% of the positives. However, 17 months after the treatment, antigenaemia was still positive in 76% of those who were parasitologically cured.Item Epidemiology of bancroftian filariasis in three suburban areas of Matara, Sri Lanka(Academic Press, 2001) Weerasooriya, M.V.; Weerasooriya, T.R.; Gunawardena, N.K.; Samarawickrema, W.A.; Kimura, E.The epidemiological parameters of bancroftian filariasis were investigated in three suburbs of Matara, within the south-western coastal belt of SriLanka where the disease is endemic. The overall prevalence of microfilaraemia and the geometric mean density of the microfilaraemias observed were 4.4% and 20.6 microfilariae/60 microl fingerprick blood, respectively. Prevalence was significantly lower in the female subjects than in the male, and in males aged < 20 years than in older males. Overall, 9.5% of the subjects had the clinical manifestations of bancroftian filariasis (6.4% had filarial fever, 3.0% had elephantiasis and/or oedema, and 6.2% had hydrocele). The prevalence of elephantiasis/oedema was generally higher among the female subjects (4.2%) than among the male (1.4%), and an age-prevalence plot for this manifestation showed a linear increase in prevalence after the age of 40 years. Hydrocele also became commoner with increasing age, but this increase in prevalence began at the lower age of 20 years. More than 60% of the cases of elephantiasis/oedema but only 26.3% of the subjects found to have hydroceles experienced filarial fever attacks. The cases of fever and elephantiasis/oedema (but not those of microfilaraemia or hydrocele) were aggregated within households. However, the children whose mothers were microfilaraemic were much more likely to be microfilaraemic themselves (8.7%) than the children who had amicrofilaraemic mothers (2.8%), microfilaraemic fathers (0.0%) or amicrofilaraemic fathers (2.7%). The results of entomological surveys indicated that transmission of Wuchereria bancrofti occurred throughout the year in the study community.Item Wuchereria bancrofti antigenaemia in Sri Lanka.(Blackwell Scientific Publications, 1999) Itoh, M.; Weerasooriya, M.V.; Gunawardena, N.K.; Mudalige, M.P.; Samarawickrema, W.A.; Kimura, E.The prevalence of Wuchereria bancrofti antigenaemia determined in 353 subjects in Matara, Sri Lanka by Og4C3 ELISA was 20.7%. Positive rates obtained with the same subjects by 1 ml Nuclepore filtration and 60 microl thick blood smear were 11.3% and 7.9%, respectively. Antigen levels were positively associated with microfilaria counts. Two-thirds of antigen-positive and microfilaria-negative (Ag+/Mf-) individuals were > 25-year-old, but younger age groups (< or = 25-year-old) tended to have proportionally more Ag+/Mf- cases. Possible origins of the Ag+/Mf- status are discussedItem The use of whole blood absorbed on filter paper to detect Wuchereria bancrofti circulating antigen(Oxford University Press, 1998) Itoh, M.; Gunawardena, N.K.; Qiu, X.G.; Weerasooriya, M.V.; Kimura, E.The Og4C3 enzyme-linked immunosorbent assay (ELISA) to detect circulating Wuchereria bancrofti antigen uses 50 microL of serum. In this study, a whole blood sample absorbed on filter paper was tested as a substitute for serum. Serum samples were obtained from 60 Sri Lankan subjects by venepuncture and finger-prick blood samples from the same individuals were directly absorbed on filter paper. Og4C3 ELISAs using serum and filter paper blood were compared. Despite the fact that the estimated amount of serum available for the ELISA with filter paper blood was only one-fifth of that available when serum was used, the 2 ELISAs gave almost identical results. Of the 39 positive serum samples, 38 were detected using filter paper blood. Employing the ELISA using filter paper blood, 619 people in Matara, Sri Lanka, were examined for antigenaemia. The positivity rate was 22.5%, 3.1 times higher than the rate of microfilaraemia detected by examination of 60 microL blood films