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This repository contains the published and unpublished research of the Faculty of Medicine by the staff members of the faculty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 Lymphatic filariasis in the Southeast Asian region; status and control options.(CABI Publishing, 2020) Chandrasena, T.G.A.N.; Premaratna, R.; Mallawarachchi, C.H.; Gunaratna, D.G.A.M.; de Silva, N.R.ABSTRACT: The Global Program to Eliminate Lymphatic Filariasis (GPELF) was launched in year 2000 by the World Health Organization (WHO) with the goal set for elimination by 2020. Over half the global disease burden lies in the Southeast Asian region (SEAR). The preventive chemotherapy (PC) programme has been initiated in all the WHO SEAR member states with varying levels of progress. Maldives, Sri Lanka and Thailand have achieved the goal of elimination as a public health problem (EPHP) within the stipulated period with Bangladesh working towards validation in 2021. Both Sri Lanka and Thailand are continuing with post-validation surveillance combined with selective treatment, striving for zero transmission in-parallel with the morbidity management and disability prevention program (MMDP). Timor-Leste appears close to reaching critical transmission thresholds with 100% coverage and triple therapy in the last round of PC. Data on MMDP activities are insufficient to comment on reaching EPHP status. PC coverage and country reports indicate ongoing transmission in Nepal, Myanmar, Indonesia and India requiring further rounds of PC. The PELF has made considerable progress in the SEAR towards elimination but there still remain significant transmission and disease burden in the highly populated countries in SEAR.Item Surveillance for transmission of lymphatic filariasis in Colombo and Gampaha districts of Sri Lanka following mass drug administration(Oxford University Press, 2016) Chandrasena, T.G.A.N.; Premaratna, R.; Samarasekera, D.S.; de Silva, N.R.BACKGROUND: Sri Lanka was recently declared by WHO to have eliminated lymphatic filariasis as a public health problem, after conclusion of annual mass drug administration. Our aim was to assess the lymphatic filariasis situation, following mass drug administration. METHODS: Surveillance was done in two districts of the Western Province in two consecutive phases (2009-2010 and 2013-2015), by examining 2461 thick night blood smears and performing 250 dipstick tests on children for antibodies to Brugia malayi. RESULTS AND CONCLUSIONS: Decline in bancroftian microfilaraemia (microfilaria rate 0.32% to zero) supports elimination, but re-emergence of brugian filariasisis (antibody rate, 1.6%; one microfilaria positive) is a cause for concern.Item Effects of antibiotics on filarial transmission(Sri Lanka College of Microbiologists, 2003) Chandrasena, T.G.A.N.; Taylor, M.J.INTRODUCTION: The symbiosis of filarial nematodes and intracellular Wolbachia bacteria has recently been exploited as a target for therapy of filariasis. OBJECTIVE: To study the effects of antibiotics on filarial transmission in-vitro. METHODS: Two groups of microfilariae (mf) of Brugia pahangi (cat filarial species) were maintained in culture and exposed to 10 µm) solutions of tetracycline and doxycycline respectively, for 48 hours. A control group of Mf was maintained for 48 hours with no added antibiotics except for those routinely included in the culture medium. Mf counts in cultures were determined at the onset of experiment (8000 mf/culture flask). Three groups of Aedes aegypti mosquitoes were artificially infected with the treated and untreated mf by membrane feeding technique (mf concentration; 2000 mf/ml of blood). Mosquito dissections were performed 2 hours and 15 days post-infection to assess mf intake and development in vector hosts. RESULTS: Mf intake was similar in the treated and the control groups {8,5 and 9 mf recovered in 4,3 and 3 mosquitoes from tetracycline(n=6), doxycycline(n=6) and control(n=6) groups respectively}. Mosquitoes fed on tetracycline treated B.pahangi (n=70) were completely free of L3 (infective larvae while in the doxycycline (n=71) and control groups (n=71) the percentage of infection was 1.4% (01 infective larva in 01 mosquito) and 24% (17 infective larvae in 13 mosquitoes) respectively. The infectivity of mosquitoes fed on antibiotic treated Mf was significantly reduced (P value < 0.001). CONCLUSIONS: Exposure of Mf of B.pahangi to physiological concentrations of anti-wolbachia antibiotics even for a brief duration significantly affects their transmission potential.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 Lymphoedema management knowledge and practices among patients attending filariasis morbidity control clinics in Gampaha district, Sri Lanka(BioMed Central, 2004) Chandrasena, T.G.A.N.; Premaratna, R.; de Silva, N.R.BACKGROUND: Little information is available on methods of treatment practiced by patients affected by filarial lymphoedema in Sri Lanka. The frequency and duration of acute dematolymphangioadenitis (ADLA) attacks in these patients remain unclear. This study reports the knowledge, practices and perceptions regarding lymphoedema management and the burden of ADLA attacks among patients with lymphoedema. METHODS: A semi-structured questionnaire was used to assess morbidity alleviation knowledge, practices and perceptions. The burden of ADLA attacks was assessed using one-year recall data. RESULTS: 66 patients (22 males, 44 females) with mean age 51.18 years (SD +/- 13.9) were studied. Approximately two thirds of the patients were aware of the importance of skin and nail hygiene, limb elevation and use of footwear. Washing was practiced on a daily and twice daily basis by 40.9 percent and 48.5 percent respectively. However, limb elevation, exercise and use of footwear were practiced only by 21-42.4 percent (while seated and lying down), 6 percent and 34.8 percent respectively. The majority of patients considered regular intake of diethylcarbamazine citrate (DEC) important. Approximately two thirds (65.2 percent) had received health education from filariasis clinics. Among patients who sought private care (n = 48) the average cost of treatment for an ADLA attack was Rs. 737.91. Only 18.2 percent had feelings of isolation and reported community reactions ranging from sympathy to fear and ridicule. CONCLUSIONS: Filariasis morbidity control clinics play an essential role in the dissemination of morbidity control knowledge. Referral of lymphoedema patients to morbidity control clinics is recommendedItem 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.