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This repository contains the published and unpublished research of the Faculty of Medicine by the staff members of the faculty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 The validation of the Sinhala version of the Kessler psychological distress scale (K10) to screen for psychiatric morbidity(Sri Lanka Medical Association, 2008) Wijeratne, L.T.; Williams, S.S.; Peris, M.U.P.K.; de Silva, N.R.; Hapuarachchi, H.A.C.; Perera, K.P.J.; Kawamura, N.; Wickremasinghe, A.R.BACKGROUND: The Kessler psychological distress scale (K10), used in epidemiological surveys, measures psychological distress. High scores in community surveys are associated with anxiety and affective disorders, and to a lesser extent, with other psychiatric disorders. OBJECTIVE: To validate the Sinhala translations of the long (K10) and short (K.6) versions of the Kessler psychological distress scale. DESIGN, SETTING AND METHODS: The English version of K10 was translated into Sinhala. Content and face validity was assessed by experts. The scales were pre-tested and modified accordingly. The Sinhala versions of K6 and K10, and the Structured Clinical Interview Schedule were administered to 20 adults with major psychiatric illnesses diagnosed by two clinicians independently, and to a random sample of 25 apparently normal people from the community. SPSS (Version 11) was used for the analysis. RESULTS: The ROC curve for the K10 contained 96.1% of the area under the curve of 0.961 (95% CI 90.4%-100%). A cut off score of 22 for the K10 yielded a sensitivity of 93.8% and a specificity of 82.6%. The ROC curve for the K6 contained 90.1% (95% CI 80.5% - 99.7%) of the area under the curve. For the K6, a cut off score of 13 gave a sensitivity of 88.2% and a specificity of 72%, The total number of days that the patient could not attend to regular work and responsibilities was significantly correlated with both the K10 (p=0.041) andK6 (p=0.023). CONCLUSION: The Sinhala version of the K10 and K6 questionnaires can be used to screen for psychological distress.Item Geographical Information System (GIS)-based maps for monitoring of entomological risk factors affecting transmission of Chikungunya in Sri Lanka(Faculty of Tropical Medicine, Mahidol University, 2008) Hapugoda, M.D.; Gunawardena, N.K.; Kusumawathie, P.H.D.; Jayasooriya, G.A.J.S.K.; Hapuarachchi, H.A.C.; Abeyewickreme, W.INTRODUCTION: Chikungunya is an important mosquito-born viral infection in Sri Lanka at present. OBJECTIVE: To prepare OUS-based maps Tor monitoring of entomological risk Factors affecting transmission of chikungunya. RESEARCH DESIGN: Entomological risk factors affecting transmission of chikungunya were examined in a chikungunya hot-spot in the District of Kandy, Sri Lanka from April to July in 2008. Hundred house-holds in 33 clusters were recruited. The distant between clusters was at least 200m which is beyond the maximum flight range of Aedes mosquitoes, the vectors of chikungunya. Monthly surveillance was conducted using standard entomological surveillance methods followed by obtaining information through a pre-tested questionnaire. G1S was used to map the selected house¬holds and display entomological data. RESULTS: GIS-based maps were developed to highlight the spatial and temporal distribution of vectors, their density and the presence of key breeding sites. Maps showed the presence of high density of Aedes albopictus mosquitoes in more than 90% of the key (artificial) breeding habitats in all clusters throughout the study period. DISCUSSION: Generalized high density of Ae. albopictus suggests that this species may play a major role in transmitting chikungunya in the study area. GIS-based 'maps may be used as an important tool to find out spatial and temporal distribution of vectors, their density and key breading sites in a selected hotspot, which would enable cost effective and efficient interventions for vector control in disease endemic areas.Item Genetic evidence of emerging sulfadoxine-pyrimethamine resistance of Plassmodium falciparum isolates in an operational area in the Northern Province of Sri Lanka(Sri Lanka Association for the Advancement of Science, 2004) Hapuarachchi, H.A.C.; Dayanath, M.Y.D.; Abeysundara, S.; Bandara, K.B.A.T.; Abeyewickreme, W.; de Silva, N.R.Item Population data for CSF1PO, TPOX, THO1, D16S539, D7S820, D13S317, FESFPS, vWA and F13B short tandem repeat (STR) polymorphisms in Sri Lanka(Sri Lanka Association for the Advancement of Science, 2004) Manamperi, A.; Gunawardene, Y.I.N.S.; Bandara, K.B.A.T.; Dayanath, M.Y.D.; Hapuarachchi, H.A.C.; Abeyewickreme, W.Item Large-scale entomological assessment of Wuchereria bancrofti transmission by dissection and PCR-ELISA in Gampaha district, Sri Lanka(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.; Bandara, K.B.A.T.; Abeyewickreme, W.Entomological surveys are important tools for monitoring progress of lymphatic filariasis (Lf) eradication programs. In this study, dissection of Culex quinquefasciatus was compared with a Polymerase Chain Reaction - Enzyme Linked Immunosorbent Assay (PCR-ELISA) for pooled mosquitoes to assess filarial infection levels in the major vector of Wuchereria bancrofti in Gampaha district, following mass-treatment programme with diethylcarbamazine (DEC) and albendazole. Mosquitoes were collected in 30 sentinel and 15 non-sentinel sites in 15 Medical Officer of Health (MOH) areas of Gampaha district known for the presence of W. bancrofti transmission. Captured mosquitoes were dissected to determine the W. bancrofti larvae (L1, L2, L3). PCR was carried out using Deoxyribonucleic acid (DNA) extracted from mosquito pools (15 body parts/pool) utilizing primers specific for the Wb-SspI repeat. PCR products were analyzed by hybridization ELISA using fluorescein-labeled wild type specific probes. The prevalence of infected/infective mosquitoes in PCR pools (3pools/site) was estimated using the PoolScreenTM algorithm and a novel probability-based method. The prevalence of infected mosquitoes with L1-L2 larvae of W. bancrofti ranged from 0%-8.54% by dissection and point estimates of infection prevalence as assayed by PCR-ELISA, ranged from 0% - 25.4%. Mosquitoes collected from all MOH areas (80%, N = 12), except for Minuwangoda, Dompe and Ragama, were positive for W. bancrofti larvae, with a prevalence rate ranging from 0.78% to 16.97% in both methods. Of 30 sentinel sites, 43.3% (N = 13) were positive for W. bancrofti transmission whereas it was evident in 40% (N = 6) of non-sentinel sites. The proportion of positive pools detected by the PCR-ELISA assay was higher than that obtained by the dissection indicating that PCR-ELISA assay is more sensitive than the dissection method in detecting infected/infective mosquitoes. Also results of this study showed that autochthonous transmission of W. bancrofti continues in the Gampaha district despite completion of the 5 year mass drug administration (MDA) programme. Therefore, we emphasize the use of more sensitive tools such as PCR-ELISA to monitor the impact of the MDA programme on disease transmission. This study also emphasizes that control measures should be further continued until the microfilareamic population is reduced to a level which could interrupt transmission in the area. Financial assistance received from WHO/SEARO/TDR (grant no. SN 1152) and University of Kelaniya (Grant no. RP/03/04/06/01/2006) is acknowledgedItem 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.Item Molecular Diagnosis for confirmation of Infectious Diseases in Sri Lanka in 2009(Sri Lanka Association for the Advancement of Science, 2009) Hapugoda, M.D.; Bandara, K.B.A.T.; Dayanath, M.Y.D.; Wellawaththage, C.; Hapuarachchi, H.A.C.; Abeyewickreme, W.Confirmation of infectious disease outbreaks in Sri Lanka is an important national requirement. Many clinicians as well as general practitioners find it difficult to confirm diagnosis of some infectious diseases only on clinical grounds. Molecular assays can rapidly confirm diagnosis at the early phase of diseases when aetiological agents are present and before antibody titers are at detectable levels. PCR-based assays are more sensitive and more specific than all conventional methods. Overall objective of this study was early, rapid and definitive laboratory confirmation of the aetiology of chikungunya, dengue, Japanese Encephalitis (JE), leishmaniasis, leptospirosis, malaria and West Nile Virus (WNV) through molecular assays. A rapid mobile investigation team equipped with the case definition, questionnaires, sample collection methods and diagnostic methods for each disease was established. This group visited outbreak areas and collected clinical and laboratory information and clinical samples from suspected patients at the early stage of symptoms: 1-5 days. Clinical samples were laboratory tested by disease specific molecular assays (PCR/RT-PCR). Clinical parameters of each disease were analyzed. Only chikungunya, dengue and leptospirosis outbreaks out of the above mentioned diseases were reported during the preceding six months in 2009. The team collected blood samples from clinically suspected cases of chikungunya (n=430), dengue (n=116) and leptospirosis (n=23) from different parts of the island. Molecular assays confirmed infections only in 81% (350/430) for chikungunya, 7% (8/116) for dengue and 9% (2/23) for leptospirosis in selected suspected patients. Reports of the confirmation of the disease outbreak by molecular assay were sent to the relevant health authority within two days to highlight the magnitude of the infection. These results showed importance of aetiological confirmation of infectious diseases by molecular assays. In conclusion, molecular diagnosis using a single clinical sample is important for rapid, definitive and early confirmation of aetiology of a particular infectious disease outbreak when serological methods are of little value at the early stage of infection. This is important for cost effective and efficient control of the outbreaks through proper clinical management.Item Evidence for emerging sulfadoxine-pyrimethamine resistance of Plasmodium falciparum isolated in the Northern Province of Sri Lanka(Sri Lanka Association for the Advancement of Science, 2005) Hapuarachchi, H.A.C.; Dayanath, M.Y.D.; Abeysundara, S.; Bandara, K.B.A.T.; Abeyewickreme, W.; de Silva, N.R.