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This repository contains the published and unpublished research of the Faculty of Medicine by the staff members of the faculty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 Recent chikungunya outbreak in Sri Lanka 2006-2007(Faculty of Tropical Medicine, Mahidol University, 2007) Abeyewickreme, W.; Bandara, K.B.A.T.; Dayanath, M.Y.D.; Sumanadasa, D.; Hapuarachchi, H.A.C.; Gunawardena, N.K.; Hapugoda, M.D.; Wijesiriwardena, B.; de Silva, S.; Perera, T.BACKGROUND: Chikungunya(CHIK) is a viral disease transmitted by Aedes mosquitoes. Cases with symptoms of CHIK had been reported from several parts of Sri Lanka in 2006-2007. Laboratory testing of samples is a prime requirement for confirmation of transmission. OBJECTIVES: To confirm CHIK infection in suspected patients by rapid Reverse Transcription Polymerase Chain Reaction Assay(RT-PCR), find out manifestations specific for CHIK infection and study the transmission of CHIK virus by vector mosquitoes. METHODOLOGY: Serura. samples and information on clinical manifestations were collected from 189 chikungunya-suspected patients from different geographical areas in Sri Lanka from September 2006 to September 2007. Samples were tested for Chikungunya RNA by RT-PCR. Amplified products were visualized by agarose gel electrophoresis. Adult mosquitoes were also collected from chikungunya case-reported stations. They were tested for Chikungunya RNA through RT-PCR-followed by agarose gel electrophoresis assay. RESULTS: Of the CHIK-suspected patients reported from all parts of the island 86/189 (45.5%) were positive for CHIK virus. Of the PCR positive 06, all had fever with either arthralgia or arthritis or both. Headache (95.3%) and backache (84.6%) were also common among above patients. Eight percent (4/50) of both species of Aedes mosquitoes were RT-PCR positive. DISCUSSION: RT- PCR is important in early diagnosis of the infection and differentiation from dengue fever. The most common clinical symptoms observed were fever with either arthralgia, arthritis or both. Both Aedes aegypti and Aedes. albopictus are important in transmitting the disease.Item A Case report of dengue and chikungunya co-infection in Sri Lanka(The Parasitology and Tropical Medicine Association of Thailand, 2008) Abeyewickreme, W.; Hapuarachchi, H.A.C.; Bandara, K.B.A.T.; Hapugoda, M.D.; Williams, S.Dengue fever and chikungunya are arboviral diseases transmitted by Aedes mosquitoes. Though dengue has been an important communicable disease in Sri Lanka for many years, chikungunya has not been reported in Sri Lanka since late 1960s. However, in November 2006, an outbreak suggestive of chikungunya erupted in the country. We report here the first laboratory confirmed case of dengue and chikungunya co-infection in Sri Lanka. The objective is to confirm the co-infection of dengue and chikungunya in a clinical case reported in November 2006. Clinical history of high fever, severe headache, nausea, loss of appetite, severe arthralgia and mild oedema of knees, small joints of hands and feet for 3 days suggested the possibility of dengue and chikungunya in a 70 year old male. There was no skin rash or bleeding manifestations. Laboratory investigations performed included total white blood corpuscle count/differential count (WBC/DC), platelet count (PLT), serum, haemoglobin (Hb%) and packed cell volume levels (PCV). Reverse Transcription- Polyrnerase Chain Reaction (RT-PCR) technology was used to confirm the presence of either dengue or chikungunya. Viral RNA was extracted from serum samples collected during the first five days of infection using QiAmp Viral RNA Kits and amplified products were visualized by 2% agarose gel electrophoresis and ethidium bromide staining. WBC/DC analysis showed a leucopaenia (WBC count 3.04 x 103 per μl) with relative lymphocytosis (51.0%). The total PLT was 115 x 103 per μl. Hb% was 14.3 g/dl with a PCV of 43.8%. The presence of both infections was confirmed by RT-PCR which amplified 225 bp and 354 bp products for dengue and chikungunya respectively. This was the first laboratory confirmed case of dengue and chikungunya co-infection, which was also the first confirmed report of chikungunya since 1969 in Sri Lanka. As clinical and biochemical manifestations of this patient suggested the probability of a mixed infection of dengue and chikungunya, the confirmation was achieved by a RT-PCR assay. This report highlights the importance of using molecular assays to confirm mixed viral infections during their early stages, especially infections such as dengue which can result in fatal complications.Item A Novel reverse transcriptase-polymerase chain reaction based-liquid hybridisation(RT-PCR-LH) assay for early diagnosis of dengue infection(Sri Lanka Medical Association, 2003) Gunasekera, M.B.; Hapugoda, M.D.; Gunasena, S.; Subasinghe, S.A.S.C.; Bandara, K.B.A.T.; Khan, K.B.; Abeyewickreme, W.BACKGROUND: Early definitive laboratory diagnosis of dengue is difficult with the tests in routine use at present. OBJECTIVE: To develop a reverse transcriptase-polymerase chain reaction based liquid hybridisation (RT-PCR-LH) technique for the rapid and early diagnosis of dengue. RESEARCH DESIGN: RT-PCR products of the NS3 gene of dengue virus prototypes and of a few positive sera for dengue virus by culture, were allowed to hybridise in liquid phase with a mixture of dengue specific radio-labelled oligonucleotides. The products were separated by PAGE and visualised by autoradiography. 78 suspected dengue sera were also tested by RT-PCR-LH method, and by IgM-ELISA and HAI tests, for comparison. RESULTS: Two DNA bands (approximately equal to 470 bp and approximately equal to 455 bp) specific to dengue virus, were observed. RT-PCR-LH assay takes only 24 h. Of the 78 suspected dengue acute sera tested, 45/78 were positive by RT-PCR-LH, 31/78 were positive by IgM-ELISA, and 14/78 had a HAI titre > or = 2560. Duration of fever was known in 72 cases, and infection was detected by RT-PCR-LH in 11/22 of cases with < 5 d fever and by IgM-ELISA in 1/22. In cases with 5 to 15 d fever RT-PCR-LH and IgM-ELISA/HAI titre > or = 2560 detected infection in 30/50 and 27/50 respectively. The 10 sera which were negative by RT-PCR-LH, but were positive by either IgM-ELISA or HAI titre > or = 2560 were all > 5 d fever cases. RT-PCR-LH together with IgM-ELISA were capable of detecting dengue infection in 56/78 of the suspected cases. CONCLUSION: RT-PCR-LH assay developed in this study appears to have an advantage over other diagnostic techniques for the early detection of dengue.