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 Development of a Snakebite risk map for Sri Lanka(Sri Lanka Medical Association, 2016) Ediriweera, D.S.; Kasturiratne, A.; Pathmeswaran, A.; Gunawardena, N.K.; Wijayawickrama, B.A.; Jayamanne, S.F.; Isbister, G.K.; Dawson, A.; Giorgi, E.; Diggle, P.J.; Lalloo, D.G.; de Silva, H.J.INTRODUCTION: Snakebite is a public health problem in Sri Lanka and about 37,000 patients are treated in government hospitals annually. At present, health care resources which are required to manage snakebite are distributed based on the administrative boundaries, rather than based on scientific risk assessment. OBJECTIVES: The aim of the study is to develop a snakebite risk map for Sri Lanka. METHOD: Epidemiological data was obtained from a community-based island-wide survey. The sample was distributed equally among the nine provinces. 165,665 participants (0.8%of the country’s population) living in 1118 Grama Niladhari divisions were surveyed. Generalized linear and generalized additive models were used for exploratory data analysis. Model-based geostatistics was used to determine the geographical distribution of snakebites. Monte Carlo maximum likelihood method was used to obtain parameter estimates and plug-in spatial predictions were obtained. Probability contour maps (PCM) were developed to demonstrate the spatial variation in the probability that local incidence does or does not exceed national snakebite incidence. RESULTS: Individual point estimate snakebite incidence map and PCM were developed to demonstrate the national incidence of snakebite in Sri Lanka. Snakebite hotspots and cold spots were identified in relation to the national snakebite incidence rate. Risk maps showed a within-country spatial variation in snakebites. CONCLUSIONS: The developed risk maps provide useful information for healthcare decision makers to allocate resources to manage snakebite in Sri Lanka.Item Estimates of disease burden due to snakebite in Sri Lankan hospitals(Sri Lanka Medical Association, 2003) Kasturiratne, A.; Pathmeswaran, A.; Fonseka, M.M.D.; Lalloo, D.G.; Brooker, S.; de Silva, H.J.INTRODUCTION: There have been no country-wide studies or estimates of disease burden due to snakebite in Sri Lankan hospitals. OBJECTIVES: To assess disease burden due to snakebite and estimate relative frequency of the biting species in hospitals situated in different parts of the country. METHODS: Hospital morbidity and mortality data on snakebite was obtained for each administrative district. Sri Lanka was divided into 5 zones based on climate and available data on snake habitat (Zone 1-wet zone altitude <900m; Z2-intermediate zone; Z3-dry zone, Z4-wet zone altitude >900m; Z5-northern and north-western dry zone). Administrative districts were allocated to zones based on their geographical location and population using geographical information systems technology. Hospital morbidity and mortality data were collated for the 5 zones. A survey among physicians (37 physicians in 42 hospitals covering the 5 zones) was used (Delphi technique) to estimate the proportion of snakebites by different species and requirement of hospital resources, in each zone. Results: There was a clear difference in incidence of hospital admissions due to snakebite in the different zones (Z3-3.5 and Z4-0.4 per 1000 population). The distribution of bites by individual species also varied between zones (deadly venomous species Z3-85%, Z2-45%), moderately venomous and mildly-venomous species Z4-100%, Zl-70%). These trends corresponded to estimates of requirements for AVS and other hospital facilities (in 2000, Z3-86100 vials of AVS, 7380 Intensive care unit patient-days; Zl-26400 vials of AVS, 2640ICU patient-days). CONCLUSIONS: Incidence of hospital admissions due to snakebite and estimates of relative medical importance of different snake species show geographic variation within the country. This is reflected in estimates of requirements for facilities. Zoning based on environmental information rather than on political boundaries could lead to better distribution of health care resources for management of snakebite in hospitals situated in different parts of the country.Item Beliefs and knowledge regarding snakebite in rural Sri Lanka: a qualitative survey(Sri Lanka Medical Association, 2003) Makita, L.S.; Nandasena, S.; Costa, M.R.A.; Kasturiratne, A.; Pathmeswaran, A.; Lalloo, D.G.; de Silva, H.J.OBJECTIVES: To identify common beliefs and assess knowledge regarding snakebite in rural Sri Lanka, and their influence on health-seeking behaviour. METHODS: Qualitative methods (focus group discussions and key informant interviews) were used to obtain data in five rural locations in wet, intermediate and dry zones. Data was subjected to "framework analysis" involving familiarisation, identification of thematic frame, indexing and coding, charting, mapping, and interpretation. RESULTS: People are aware of risk-behaviour associated with snakebite, and have reasonable knowledge regarding venomous and non-venomous snakes. However, differences in nomenclature sometimes lead to confusion in identifying species. Beliefs and legends, which are linked to religion, have lead people to respect the cobra. Traditional healers claim they can determine the snake species, clinical manifestations that may occur, and prognosis, based on phenomena, such as, day of the week and phase of the moon when the bite took place. They still employ treatment methods, such as wound incision with broken glass and scalp incision for applying potions. Although there is respect for traditional healing, there is acceptance of the efficacy of western medicine. Beliefs, such as, anti-venom though effective is toxic, long-term effects of snake venom can be completely neutralised only by traditional medicine, and producing the dead snake is essential for treatment in hospitals, lead people to seek treatment by traditional healers rather than in hospitals. CONCLUSIONS: Beliefs and misconceptions influence health-seeking behaviour following snakebite. There seems to be a growing acceptance of western medicine. However, traditional healing methods are still popular, but include harmful^rjractices. This information could form a basis for. educational intervention.Item Community incidence of snakebite in the Amiradhapura district(Sri Lanka Medical Association, 2013) Kasturiratne, A.; Gunawardena, N.K.; Wijayawickrama, B.A.; Jayamanne, S.F.; Pathmeswaran, A.; Isbister, G.; Dawson, A.; de Silva, H.J.INTRODUCTION AND OBJECTIVES: The community incidence of snakebite in Sri Lanka is unknown. To investigate incidence of snakebite, we undertook a community study in the Anuradhapura district as part of an ongoing countrywide survey on snakebite. METHODS: The survey was designed to sample at least 1% of the population in each district Within the district, a Grama Niladhari (GN) division, was defined as a cluster for data collection. The number of clusters required to sample at least 1 % of the population was first determined, and clusters were then selected using simple random sampling. In each selected cluster 40 households were sampled consecutively from a random starting point. Population estimates of snakebite were constructed for the district. RESULTS: The Anuradhapura district has a total of 694 GN divisions, and 84 were surveyed. This included 3357 households and a population of 13,428 (1.6% of the district's population). Eightysix snakebites were reported within the last 12 months. Extrapolating this to the district (mid-year population=855,373), the estimated snakebites in Anuradhapura district was 5478. The crude community incidence of snakebite in the Anuradhapura district was 640.5 per 100, 000 population. CONCLUSIONS: The incidence of snakebite in the community is high in the Anuradhapura district, with one in 156 persons bitten annually.Item Prevention of acute adverse reactions to snake antivenom after snakebite: multi-centre, randomized, controlled clinical trial(Sri Lanka Medical Association, 2009) de Silva, H.A.; Ranasinha, C.D.; Pathmeswaran, A.; Jayamanne, S.; Kalupahana, R.; Ratnathilake, G.A.; Ariyasena, H.; Uluwatte, W.; Lalloo, D.; Armitage, J.; Aronson, J.K.; de Silva, H.J.BACKGROUND: Antivenom is the most effective treatment for snakebite envenoming. Acute adverse reactions to the polyvalent antivenom (PAV) are common; anaphylactk reactions are particularly serious. OBJECTIVE: To determine whether promethazine, hydrocortisone, and low-dose adrenaline, alone and in all possible combinations, prevent reactions to antivenom. METHODS: The study was conducted in 3 hospitals in Sri Lanka from March 2005 to April 2008. It required 1000 patients to detect a 25% reduction in reactions at p<0.01 with 80% power. After informed consent, patients were randomized in a 2x2x2 factorial blinded design to receive each active intervention versus matching placebo immediately before administration of PAV. They were monitored for adverse reactions categorized as mild, moderate, severe, for at least 96 hours. The pre-specified primary analyses were of effects of each intervention on the incidence of severe reactions over 48 hours. Results: Of 1007 randomized subjects 776 (77.2%) were males, mean (sd) age 36.5 (13.6) yrs. Median time between snakebite and PAV administration was 4.25 hours. 752 (75%) patients developed acute reactions to PAV; 9% mild, 48% moderate and 43% severe. None of the drugs significantly reduced severe reactions to PAV at any time point. However, there was an 18% reduction in the rate of severe reactions at 1 hour with adrenaline (p-0.052) and a 33-3% reduction in signs of allergy (pruritus, urticaria, facial oedema, bronchospasm) with promethazine at 1 and 24 hours (p<0.001). CONCLUSIONS: Pre-treatment with promethazine, hydrocortisone, and low-dose adrenaline alone and in different combinations do not significantly reduce acute reactions to PAV.