Conference Papers
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This collection contains abstracts of conference papers, presented at local and international conferences by the staff of the Faculty of Medicine
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Item Detection of Dengue Viral Migration to Sri Lanka(19th Conference on Postgraduate Research, International Postgraduate Research Conference 2018, Faculty of Graduate Studies,University of Kelaniya, Sri Lanka, 2018) Withanage, G.P.; Hapuarachchi, H.C.; Gunawardene, Y.I.N.S.; Hapugoda, M.D.Dengue is one of the most important mosquito-borne viral infectionsin Sri Lanka.The causative agent is Dengue Viruses (DENV) and the primary vector of the virus is Aedesaegypti(Linnaeus) while Ae. albopictus (Skuse) is the subsidiary vector. The current research was focused on the detection of DENV serotypes and genotypes circulating in mosquitoes during the dengue epidemic in June and July, 2017 in the EriyawetiyaGramaNiladhari division, where one of the dengue high-risk area in Kelaniya Medical Officer of Health (MOH) area in the District of Gampaha, Sri Lanka. Aedesmosquitoes were collected following WHO guidelinesandthe field-caught mosquitoes were transported to the laboratory for species identification and subsequent analysis. Head and thorax of each mosquito was removed and mosquito samples were pooled separately. Total RNA was extracted from mosquito samples and semi-nested Polymerase Chain Reaction (PCR) was performed to identify DENV serotypes present in the mosquito samples. The results of the PCR indicated the presence of DENV2 in both Ae. aegypti (1/5) and Ae. albopictus (1/27) mosquitoes. Then complete Envelope (E) gene was amplified with DENV2 specific primers for genotyping of the virus which is required to identify the molecular evolution of the DENV2. Prior to sequencing the PCR products were purified and sequencing results were analyzed usingLaserGene software. The generated sequences were aligned with retrieved DENV2 sequences available at NCBI database and the phylogenetic trees were developed using MEGA7 software with General Time Reversible (GTR) substitution model with gamma distributed rates. The robustness of clades was determined by using bootstrap analysis of 500 replicates. The result of the phylogenetic analysis illustrates that the E gene sequences of DENV2 obtained from two DENVpositive mosquito poolsbelong to DENV2 Cosmopolitan Clade Ib, which has been the dominant strain in South-East Asia, specially Singapore, Indonesia, Malaysia, and China since August, 2015.The evidence suggests recent introduction of this DENV strain into Sri LankaItem Entomological investigations on malaria vector studies in earlier conflict areas of Sri lanka after 30 years(University of Peradeniya, 2014) Gunathilaka, P.A.D.H.N.; Fernando, M.A.S.T.; Hapugoda, M.D.; Wijeyerathne, P.; Wickremasinghe, A.R.; Abeyewickreme, W.Entomological investigations on the abundance of malaria vector mosquitoes have not been studied in northern and eastern parts of the Sri Lanka over the past 30 years due to the separatist war. The main aim of this study was to explore diversity and abundance of Anopheles mosquitoes in earlier conflict areas in Sri Lanka. Monthly entomological monitoring was carried out at 60 possible malaria sensitive localities situated approximately 12 km apart in 15 selected sentinel sites in Ampara (4), Batticaloa (3), Mannar (3) and Trincomalee (5) districts for 32 months (June 2010 to August 2013). Adult mosquitoes were collected by WHO recommended techniques. Out of 701,356 anophelines collected, An. culicifacies was noted only in Ampara, Batticaloa and Trincomalee Districts. Although the main vector An. culicifacies (n= 1,876) was low in numbers, the presence of secondary vectors including An. subpictus (n= 205,594) were high in these areas. An. nigerrimus (n= 227,057), An. barbirostris (n= 35,150), An. vagus (n= 21,161), An. pallidus (n= 17,403), An. annularis (n= 4,882), An. varuna (n= 3151), An. tessellatus (n= 718) and An. aconitus (n= 591) were the other species reported. There was a change in breeding habitats of An. culicifacies and An. subpictus. They were found more conducive to breeding in built wells, brackish water habitats and waste water collections which were below 3 mg/l of dissolved oxygen (2.85 ± 0.03). These results indicate that particularly An. culicifacies has adapted to breed in wide range of water bodies including waste water collections although they were earlier considered to breed in clean and clear water with high dissolved oxygen. The adaptation of the major and subsidiary vector mosquitoes to widespread water bodies (along with increase in imported cases) could be a potential factor for the increase in the incidence of malaria in the future even though reported cases are low at present. Further, entomological surveillance detected the presence of An. jeyporiensis from the country after 106 years. Hence, more classical entomological studies are required to describe species currently found in the country; revision of morphological identification keys is a step in this direction. Financial assistance given by the Global Fund for Aids, Tuberculosis and Malaria (GFATM-Round 8-SRL809G11M.) through TEDHA malaria elimination program is acknowledged.Item Role of Aedes albopictus in transmitting dengue virus in some endemic areas in Kurunegala District.(University of Kelaniya, 2003) Hapugoda, M.D.; de Silva, N.R.; Abeysundara, S.; Bandara, K.B.A.T.; Dayanath, M.Y.D.; Abeyewickreme, W.Abstract AvailableItem A Preliminary study of genetic estimates of population structure of Aedes aegypti populations in three districts, Sri Lanka(Sri Lanka Association for the Advancement of Science, 2014) Fernando, H.S.D; Hapugoda, M.D.; de Silva, B.G.D.N.K.Item Silent transmission as a risk factor affecting transmission of dengue fever.(Faculty of Veterinary Medicine and Animal Science, University of Peradeniya, 2007) Hapangama, H.A.D.C.; Hapugoda, M.D.; Gunawardene, Y.I.N.S.; Premaratna, R.; Dayanath, M.Y.D.; Abeyewickreme, W.The global incidence of dengue fever has increased by more than four-folds over the last 30 years, making it the most threatening mosquito-borne viral disease at present. Objective of this study is to determine the role of silent transmission •on' incidence of dengue. A total of 40 households, living within a 300 m radius of seven selected ‘confirmed dengue cases at different dengue high risk localities in Gampaha District were recruited for this study. A minimum of three inhabitants were tested for anti-dengue antibodies using a commercial kit to determine the prevalence of silent transmission on dengue infection in each households. Entomological surveillance was carried out in all seven localities. Out of 40 households, 26 (65%) houses were positive for dengue viral infection. Total of 148 inhabitants (68 Males); mean age; 35.9 years were enrolled. Of the 148, 41 (27.7%) had evidence of exposure to dengue virus [positive for IgM: 28/41(68.4%), IgM'& IgG: 7/41(17%) and IgG: 6/41(14.6%)]. Out of 28 primary infections, 20(71.4%) were asymptomatic. Of the 7 secondary infections, 1(14.28%) was asymptomatic. Of the 6 previous exposures to dengue 4(66.67%) were asymptomatic. Of the 7 localities investigated, 1 had >50%, 4 had >25% and 2 had <25% clustering of cases. Ae. albopictus found in all seven localities and Ae. aegypti found only in two localities. This study suggests presence of silent transmission of dengue virus with a trend towards clustering around cases and also this shows that the presence of vectors increases the incidence of dengue.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 Occurrence of a dengue epidemic in Minipe valley of the Kandy district: evidence for Aedes albopictus being an epidemic vector of dengue in Sri Lanka(Sri Lanka Association for the Advancement of Science, 2011) Kusumawathie, P.H.D.; Jayasooriya, G.A.J.S.K.; Abeyewickreme, W.; Hapugoda, M.D.Item Comparison of different RNA extraction methods for Dengue Reverse Transcription -Polymerase Chain Reaction (RT-PCR)(Sri Lanka Association for the Advancement of Science, 2011) Adihetty, D.D.; Wellawaththage, C.; Abeyewickreme, W.; Abeywickrema, K.; Hapugoda, M.D.Item Trends in densities of Anopheles culicifacies (Giles) and other potential malaria vector mosquitoes in the district of Trincomalee(Sri Lanka Association for the Advancement of Science, 2013) Gunathilaka, P.A.D.H.N.; Fernando, M.A.S.T.; Hapugoda, M.D.; Wijeyarathne, P.; Wickremasinghe, A.R.; Abeyewickreme, W.Item Evaluation of a case definition for leptospirosis diagnosis using serological assays(Sri Lanka Association for the Advancement of Science, 2013) Denipitiya, D.T.H.; Jiffriy, A.M.; Chandrasekharan, N.V.; Abeyewickreme, W.; Hapugoda, M.D.