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 Geographic information system (GIS) mapping of lymphatic filariasis endemic areas of Gampaha District, Sri Lanka based on epidemiological and entomological screening(SEAMEO Regional Tropical Medicine and Public Health Project, 2012) Wijegunawardana, N.D.A.D.; Gunawardene, Y.I.N.S.; Manamperi, A.; Senarathne, H.; Abeyewickreme, W.The objective of this study was to develop a site directed geographic information system (GIS) map of lymphatic filariasis (LF) in Gampaha District, Sri Lanka as a guide for targeted control activities. Epidemiological and entomological screening of LF was carried out in nine pre-identified endemic areas in Gampaha District, using night blood screening and pool-screening PCR-ELISA. In total, 1,073 subjects (286 children, 787 adults) from 9 sites were examined. Positive cases were detected at 2 sites, with prevalence rates of 0.5% (Hekiththa) and 3.4% (Peliyagoda); the prevalence of microfilaria (mf) among adult Culex quinquefasciatus mosquitoes surveyed was 30%. The overall prevalence of mosquitoes with L1-L2 larvae of W. bancrofti ranged from 0% to 8.31% using dissection and point estimates of infection prevalence, and ranged from 0 to 32.4% using PCR-ELISA. The largest number of human cases was found at altitudes of 2.5-3.5 min highly populated areas, where transmission appears to have taken place. Questionnaires indicated that limited community awareness of LF may be a reason for the fairly static infection prevalent among the local population. The GIS mapping of LF cases shows a considerable prevalence of LF and marked variability by geographic site in Gampaha.Item Complicance with single-dose diethylcarbamazine citrate (DEC) mass treatment programme for filariasis in Colombo, Sri Lanka(World Health Organization Regional Office for South-East Asia, 2002) Weerasinghe, C.R.; Abeyewickreme, W.; de Silva, N.R.AvailableItem Red blood cell antioxidant levels in Wuchereria bancrofti infections(Academic Press, 2002) Premaratna, R.; Chandrasena, T.G.A.N.; Abeyewickreme, W.; Chandrasena, L.G.; Senerath, S.; de Silva, N.R.; de Silva, H.J.The elimination of microfilariae of Wuchereria bancrofti is probably mediated by free radicals. Red cell catalase (C), glutathione peroxidase (GPX), and superoxide dismutase (SOD) activity levels were measured as an indirect method of assessing blood oxidant status in 29 asymptomatic microfilaraemics, 29 "endemic normals", and 29 controls living in a non-endemic area. Changes in the activity of these enzymes were also compared over a one month period in 22 asymptomatic microfilaraemics randomised to receive either single dose or 14 day treatment with diethyl carbamazine citrate (DEC). Red cell GPX activity levels were significantly higher in "endemic normals" when compared to mf positive cases and non-endemic controls. An early and significant increase in GPX activity (on days 3, 7 and 14 compared to pretreatment levels, p<0.01) was observed after DEC in both treatment groups. Increases in the activity of catalase and SOD became significant only on days 14 and 30 respectively. The percentage reduction in microfilaraemia correlated significantly with the percentage increase in GPX activity levels (R(2)=0.58, p=0.6 x 10(-5)). Our results may suggest a role for GPX related oxidant species in the elimination of microfilariae.Item Evaluation of the ICT whole-blood antigen card test to detect infection due to Wuchereria bancrofti in Sri Lanka(Oxford University Press, 2002) Chandrasena, T.G.A.N.; Premaratna, R.; Abeyewickreme, W.; de Silva, N.R.The sensitivity, specificity and cost effectiveness of an immunochromatographic card test (ICT, AMRAD) for the diagnosis of bancroftian filariasis were estimated against 2 standard parasitological techniques: thick blood film (TBF) and Nuclepore membrane filtration (NMF). Individuals were selected from endemic localities in the Western Province (n = 213) and from the non-endemic Central Province (n = 29) of Sri Lanka. Blood was collected between 21:00 and midnight. Sixty microlitre of non-heparinized blood, and 1 mL and 100 microL of heparinized blood were used in TBF, NMF andICT, respectively. NMF was positive in 31.5% (67/213) of the endemic group, with a mean microfilaria (mf) count of 343/mL (range 8-1782, SD 422). All 67 were positive by ICT (sensitivity 100%), but only 63 by TBF (sensitivity 94%). Among the endemic population there were 12 who were mf negative but antigen positive by ICT. There were, however, no false positives among the non-endemic controls, indicating the possibility that the ICTmay in fact be more sensitive and 100% specific. Thus, ICT filariasis test appears to be more effective (both sensitive and specific) than TBF or NMF in diagnosing infection in lymphatic filariasis. The direct unit recurrent costs of the 2 survey tools, TBF and ICT, were US$ 0.30 (Rs. 27/=) and US$ 2.75 (Rs. 248/=), respectively. The high cost of the ICT may be offset by other factors that are difficult to cost.Item Efficacy of single dose combinations of albendazole, ivermectin and diethylcarbamazine for the treatment of bancroftian filariasis(Oxford University Press, 1998) Ismail, M.M.; Jayakody, R.L.; Weil, G.J.; Nirmalan, N.; Jayasinghe, K.S.A.; Abeyewickreme, W.; Sheriff, M.M.R.; Rajaratnam, H.N.; Amarasekera, N.; de Silva, D.C.; Michalski, M.L.; Dissanaike, A.S.In a 'blind' trial on 50 male asymptomatic microfilaraemic subjects with Wuchereria bancrofti infection, the safety, tolerability and filaricidal efficacy of a single dose of albendazole (alb) 600 mg alone or in combination with ivermectin (iver) 400 microg/kg or diethylcarbamazine citrate (DEC) 6 mg/kg was compared with a single dose of the combination DEC 6 mg/kg and iver 400 micro g/kg over a period of 15 months after treatment. All but one subject, with 67 micro filariae (mf)/mL, had pre-treatment counts 100 mf/mL. All 4 treatments significantly reduced mf counts, but alb/iver was the most effective regimen for clearing mf from night blood: 9 of 13 subjects (69 percent) were amicro filaraemic by membrane filtration 15 months after treatment compared to one of 12 (8 percent), 3 of 11 (27 percent), and 3 of 10 (30 percent) in the groups treated with alb, alb/DEC, and DEC/iver, respectively. Filarial antigen tests suggested that all 4 treatments had significant activity against adult W. bancrofti; alb/DEC had the greatest activity according to this test, with antigen levels decreasing by 77percent 15 months after therapy. All 4 regimens were well tolerated and clinically safe, although mild, self-limited systemic reactions were observed in all treatment groups. These results suggest that alb/iver is a safe and effective single dose regimen for suppression of micro filaraemia in bancroftian filariasis that could be considered for control programmes. Additional benefits of this combination are its potent, broad spectrum activity against intestinal helminths and potential relative safety in areas of Africa where DEC cannot be used for filariasis control because of co-endemicity with onchocerciasis or loiasisItem Prolonged clearence of microfilaraemia in patients with bancroftian filariasis after multiple high doses of ivermectin of diethylacarbamizine(Oxford University Press, 1996) Ismail, M.M.; Weil, G.J.; Jayasinghe, K.S.A.; Premaratne, U.N.; Abeyewickreme, W.; Rajaratnam, H.N.; Sheriff, M.M.R.; Perera, C.S.; Dissanaike, A.S.In a double-blind trial on 37 asymptomatic microfilaraemic subjects (minimum 400 microfilariae [mf] per mL) with Wuchereria bancrofti infection, the safety, tolerability and macrofilaricidal efficacy of 12 fortnightly doses of ivermectin, 400 microg/kg (ivermectin group), was compared with 12 fortnightly doses of diethylcarbamazine (DEC), 10 mg/kg (DEC group), over a period of 129 weeks after treatment. A control group (LDIC group) was treated with low dose ivermectin to clear microfilaraemia, for ethical reasons. Both ivermectin and DEC in high multiple doses were well tolerated and clinically safe. Macrofilaricidal efficacy was assessed by prolonged clearance of microfilaraemia, appearance of local lesions, and reduction of circulating W. bancrofti adult antigen detected by an antigen capture enzyme-linked immunoassay based on the monoclonal antibody AD12. Mf counts fell more rapidly after ivermectin than after DEC, but low residual mf levels were equivalent in these groups after week 4. Conversely, filarial antigen levels fell more rapidly after DEC than after ivermectin, but low residual antigen levels in these groups were statistically equivalent at all times beyond 12 weeks. Mild, self-limited systemic reactions to therapy were observed in all 3 treatment groups. Local reactions, such as development of scrotal nodules, were observed in several subjects in the DEC and ivermectin groups. These results suggested that high dose ivermectin and DEC both had significant macrofilaricidal activity against W. bancrofti, but neither of these intensive therapeutic regimens consistently produced complete cures. Thus, new drugs or dosing schedules are needed to achieve the goal of killing all filarial parasites in the majority of patients.Item Effect of ivermectin on the development of Wuchereria bancrofti in the vector(Malaysian Society of Parasitology and Tropical Medicine, 1992) Abeyewickreme, W.; Ismail, M.M.; Premaratne, U.N.; Dissanaike, A.S.Item Treatment of bancroftian filariasis with ivermectin in Sri Lanka, evaluation of efficacy and adverse reaction(Malaysian Society of Parasitology and Tropical Medicine, 1991) Ismail, M.M.; Premaratne, U.N.; Abeyewickreme, W.; Jayasinghe, K.S.A.; de Silva, W.A.S.; Atukorala, S.; de Abrew, K.; Dissanaike, A.S.Item Anopheles (Cellia) jamesii: a potential natural vector of Bancroftian filariasis in Sri Lanka(Oxford University Press, 1991) Abeyewickreme, W.; Wanniarachchi, P.No Abstract AvailableItem Anopheles (Cellia) culicifacies: a potential vector of bancroftian filariasis in Sri Lanka(Museum and Reference Centre, SEAMEO-TROPMED National Centre of Thailand, 1987) Abeyewickreme, W.; Hewadikaram, K.A.; Weerasena, K.H.; Premaratne, U.N.; Ismail, M.M.