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This repository contains the published and unpublished research of the Faculty of Medicine by the staff members of the faculty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 Breeding of aedes Aegypti and Aedes albopictus in some dengue endemic areas.(Sri Lanka College of Microbiologists, 2000) Hapugoda, G.P.G.M.D.; de Silva, N.R.; Abeyewickreme, W.Dengue fever (DF)/Dengue haemorrnagic fever (DHF) is now- the most important and rapidly spreading vector borne disease in the world. Since 1956, over 350 000 patients have been hospitalized and nearly 12 000 deaths have been reported. In Sri Lanka the incidence of DF/DHF has increased cyclically since the first outbreak in Sri Lanka during which 26 deaths were reported. Aedes aegypti is classified as the predominant vector of dengue in Sri Lanka. Ae, albopictus is considered as an important vector in the absence of Ae. aegypti. In this study, larval surveillance was carried out in fixed monitoring stations / hot-spots and random monitoring stations. Fixed monitoring stations were selected based on high incidence of DF/DHF recorded since 1996 in Kurunegala district. Ten premises within one fixed monitoring station were checked for mosquito breeding weekly using ovitraps and the average monthly ovitrap index (%) was calculated. During outbreaks larval surveillance was conducted in fifteen random monitoring stations including 66 houses which were selected based on serologically confirmed DPI DHF cases in and around Kurunegala and Ragama. Observations on average monthly ovitrap index (%) in the fixed monitoring stations showed that the highest ovitrap index was in Kurunegala town area, Ovitrap index of Ae. albopictus was higher than of Ae. aegypti all localities in and around Kurunegala throughout the study period. Data obtained from random monitoring-stations in and around Kurunegala and Ragama revealed that only Ae. albopictus larvae were present in seven stations. There were no stations in which only Ae.aegypti larvae were present. House index of Ae. albopictus was 28% whereas it was 10.6% for both species in random monitoring stations. Results suggest that Ae.albopictus may play a major role in transmitting dengue in some localities in Sri Lanka. This investigation received financial support from University of Kelaniya (Research Grant no-97/1-23) and from the IAEA (Technical Corporation Grant no-SRL/06/024).Item Potential use of IGR Pyriproxifen for control of dengue vector Aedes albopictus(Sri Lanka College of Microbiologists, 1999) Gunawardene, Y.I.N.S.; de Silva, N.R.; Abeyewickreme, W.Dengue Fever (DF) Dengue Haernorrhagic Fever (DHF) is now a significant problem in Sri Lanka. The incidence of DHF has increased cyclically since the first recognized outbreak in 1989. Of the 203 suspected DHF cases recorded in 1989, 87 were confirmed and 26 deaths were reported. By 1997, 5882 clinical cases, 1558 serologically confirmed cases and over 300 deaths have been reported. Without an effective vaccine against dengue, and considering the clinical difficulty in managing DHF cases, vector control has become an important com¬ponent in the integrated attempts for dengue con¬trol. Aedes aegypti and Aedes albopictus not only transmit dengue but are also a nuisance and cause annoyance by their day biting behaviour. In this study an attempt was made to control Ae. albopictus by exploiting its oviposition behaviour, us¬ing an Insect Growth Regulator (IGR), Pyriproxifen. The IGR is known to interfere with the synthesis and deposition of chitin in insects and thereby prevent growth and development. Different concentrations of the IGR (0.01 g/1 -0.08g/1) were tested against Ae.albopictus, in laboratory experiments. The most effective larvisidal concentration of Pyriproxifen for Ae.albopictus was determined to be 0.03g/1. Field trials were also carried out to determine the feasi¬bility of employing used automobile tyres contain¬ing Pyriproxifen as ovitraps against Ae.albopictus. Tyres containing water were treated with Pyriproxifen (0.03g/1) and the emergence of adults was recorded. Pyriproxifen at a concentration of 0.03g/1 was found to inhibit the emergence of adult Aedes mosquitoes up to 6 weeks.Item A Study on cost of caring for patients with dengue fever at Professorial Medical Unit, Colombo North Teaching Hospital(Sri Lanka Association for the Advancement of Science, 2008) Hapangama, H.A.D.C.; Attanayake, N.; Premaratna, R.; Abeyewickreme, W.Dengue fever (DF) and Dengue Hemorrhagic Fever (DHF) may constitute a substantial economic burden on both the healthcare system and individual households in Sri Lanka. The objective of this study was to determine cost of caring for patients with DF and to determine the economic impact of DF on households and healthcare institution. The direct economic impact of the healthcare system and on the households of 31 laboratory confirmed dengue patients who were managed in the professorial medical wards of the North Colombo Teaching Hospital, Ragama was assessed during October, 2006 to March, 2007. The institutional cost was calculated using data obtained from relevant departments of the hospital. The cost for the households of each patient was calculated using an interviewer administrated questionnaire. Of the 31 patients enrolled all had DF and none developed DHF. The median and mode for hospital admission of study sample was third day of fever (range 1-7). The mean Direct Household Cost (DHC) for a single day in hospital of a dengue patient was Rs 820.06. Over 90% of DHC consisted of cost for transportation (33.22%), food (30.44%) and for services obtained from outside hospital sources (30.14%). The mean basic institutional cost for a patient-day in a medical ward of the hospital (excluding the cost for specific management of an illness) was Rs.961.81. Total institutional cost of caring dengue patient per day was Rs. 1142.57 which comprised of cost for basic inpatient care (84.2%) and specific management of dengue fever (15.82%). Further, total cost of hospitalization due to dengue for the study sample comprised of 6.5% for drugs, 17% for investigations and 76.5% for accommodation, staff, transportation, food and other expenses. The study shows a considerable economic burden for both hospital and households due to hospitalization with dengue fever. Although this study focused on some aspects of curative care, primary prevention should be regarded as the basis for minimizing the economic and social burden. The rising demand for the laboratory investigations needs to be addressed by the public sector in a more systematic manner. The substantial burden on the household can be reduced by integration of the private sector in to the system in a rational manner and ensuring a pricing policy. "All medical and nursing staff of the Medical Wards of the North Colombo Teaching Hospital and staff of the Molecular Medicine Unit are gratefully acknowledged."Item Knowledge, attitudes and practices (KAP) on dengue control in Gampaha district.(Sri Lanka Association for the Advancement of Science, 2008) Abeyewickreme, W.; Hapangama, H.A.D.C.; Gunawardene, Y.I.N.S.; Hapugoda, M.D.; Gunawardena, N.K.; Wickremasinghe, A.R.Dengue/Dengue Hemorrhagic Fever (DHF) has become a major public health problem in many parts of the tropics. In Sri Lanka, it is endemic in some parts of the country with outbreaks of dengue/ DHF. The present study was done to assess 1) knowledge regarding dengue among the general population in the district of Gampaha, 2) whether simple preventive measures are being practiced in the community. A cross-sectional survey was conducted in selected 2000 households in the Gampaha District from June - August, 2007 using a pre-tested structured questionnaire to assess the level of knowledge, attitudes and practices regarding dengue. The majority of the respondents interviewed were females (65.2%). More than 90% have had secondary education (90.2%). The main source of water supply were pipe borne (43.4%) and well water (40.6%). 64.3% households stored water for washing, drinking and cleaning purposes. More than 95% of the respondents had heard about dengue fever and its transmission. 91.3% cited that their main source of information on dengue was from television/radio. 34.3% had either received advice or participated in a training programme on dengue prevention and 7.8% had received support materials. The main preventive measure used to reduce the mosquito nuisance was personal protection with repellents (73.6%). Most of the respondents (56.8%) felt that no action was taken by the government to control mosquitoes. When respondents views were taken, the suggestions made by them to improve dengue control included, fogging (31.8%), educating people (30.5%), treating water (24.3%) and cleaning the environment (19.5%). When questions were directed at possible methods for community participation for dengue control, the majority were in favour of removing solid waste (84.15%), eliminating stagnant water collections (40.7%), removing larvae (8.75%) and covering all the water containers using lids (8.1%). The community had good understanding on dengue and the main source of information was from the electronic media. However it was found that good knowledge itself does not necessarily lead to good practices. The respondents' attitudes were found to be good and most of them were supportive of control measures. Mass media is an important means of conveying health messages to the public, thus research and development of educational strategies designed to improve behaviour and practices of effective control measures through mass media among the community are recommended. Financial support by World Health Organization TDR/WHO Multi Country Study on "Eco-Bio-Social Research on Dengue in Asia" is acknowledged.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.