Browsing by Author "Wijayawickrama, B.A."

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Community incidence of snakebite and envenoming in Sri Lanka; results of a national survey
(Sri Lanka Medical Association, 2014) Pathmeswaran, A.; Kasturiratne, A.; Gunawardena, N.K.; Wijayawickrama, B.A.; Jayamanne, S.F.; Ediriweera, D.S.; Isbister, G.; Dawson, A.; Lalloo, D.G.; de Silva, H.J.
INTRODUCTION AND OBJECTIVES: We undertook the first ever country-wide community-based survey to determine the incidence of snakebite in Sri Lanka. METHODS: Data were collected through household interviews by trained data collectors.125 clusters were allocated to each of the 9 provinces of the country. Within each province the clusters were divided among the districts in proportion to their population. A Grama Niladhari (GN) division was defined as a cluster for data collection. The clusters were selected using simple random sampling, and in each cluster 40 households were sampled consecutively from a random starting point. RESULTS: Data relating to 165,665 individuals (0.8% of the population of Sri Lanka) living in 44,136 households in 1,118 clusters was collected from June 2012 to May 2013. 695 (males 418) snakebites and 323 (males!93) significant envenomings (local tissue necrosis or systemic envenoming) were reported during the 12 months preceding the interview. The overall community incidence of snakebites and significant envenoming were 398 and 151 per 100,000 population, respectively. 446 (64.2%) bites and 208 (64.4%) envenomings were in people aged 30 to 59 years. There was wide variation between districts, the worst affected being Mullaitivu, Anuradhapura, Batticaloa, and Poionnaruwa, ali in the dry zone, mainly agricultural areas of the country. CONCLUSIONS: Sri Lanka has a high community incidence of snakebite and envenoming with a marked geographical variation.This variation underlines both the inaccuracy of extrapolating data of localised surveys to national or regional levels and the need to prioritise distribution of resources for treatment of snakebite even in small countries.
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.
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.
Health seeking behavior of snakebite victims in Sri Lanka: findings from an island-wide community-based study
(Sri Lanka Medical Association, 2014) Kasturiratne, A.; Pathmeswaran, A.; Gunawardena, N.K.; Ediriweera, E.P.D.S.; Wijayawickrama, B.A.; Jayamanne, S.F.; Isbister, G.; Dawson, A.; Lalloo, D.G.; de Silva, H.J.
INTRODUCTION AND OBJECTIVES: Health seeking behaviour of snakebite victims in the community has rarely been described and we investigated this as part of a community-based island-wide study on snakebite in Sri Lanka. METHODS: The national snakebite study was conducted in a!! 25 districts, in SriJ_anka in 2012/2013. 44,136 households were sampled in randomly selected clusters. In these households, any member reported to have experienced a snake bite within the preceding 12 months was considered a case. Data related to the health seeking behavior of snakebite were obtained using an interviewer-administered questionnaire. RESULTS: Among 165,665 individuals surveyed, 695 (60% males; median age 43 years) snakebite victims were identified. 323 (46.5%) had evidence of envenoming. 682 (98.2%) had sought health services after the bite. 381 (54.8%) sought allopathic medicine and 99.7% of them obtained this service from the state health sector, while 43.3% sought alternative medicine. The lowest rates of seeking allopathic medicine were seen in the Kalutara (8.7%) and Kegalie (10.7%) districts while highest rates were seen in the districts Mannar, Mullativu and Kilinochchi (100%). Puttalam (92.9%), Vavuniya (92.3%},) Ampara (89.5%), Jaffna (88.9%) and Anuradhapura (86.0%) also had high rates. 70.1% of the victims with envenoming sought allopathic medicine. Victims who had envenoming were significantly more likely to seek allopathic medicine (OR=3.35; 95% confidence interval 2.44-4.59) than those without envenoming. CONCLUSIONS: A considerable proportion of snake bite victims still seek alternative medicines in Sri Lanka.'A wide variation of practices exists across the country. Victims with envenoming are more likely to seek allopathic medicine.
Mapping the risk of snakebite in Sri Lanka - A national survey with geospatial analysis
(Public Library of Science, 2016) Ediriweera, E.P.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.
BACKGROUND: There is a paucity of robust epidemiological data on snakebite, and data available from hospitals and localized or time-limited surveys have major limitations. No study has investigated the incidence of snakebite across a whole country. We undertook a community-based national survey and model based geostatistics to determine incidence, envenoming, mortality and geographical pattern of snakebite in Sri Lanka. METHODOLOGY/PRINCIPAL FINDINGS: The survey was designed to sample a population distributed equally among the nine provinces of the country. The number of data collection clusters was divided among districts in proportion to their population. Within districts clusters were randomly selected. Population based incidence of snakebite and significant envenoming were estimated. Model-based geostatistics was used to develop snakebite risk maps for Sri Lanka. 1118 of the total of 14022 GN divisions with a population of 165665 (0.8%of the country’s population) were surveyed. The crude overall community incidence of snakebite, envenoming and mortality were 398 (95% CI: 356–441), 151 (130–173) and 2.3 (0.2–4.4) per 100000 population, respectively. Risk maps showed wide variation in incidence within the country, and snakebite hotspots and cold spots were determined by considering the probability of exceeding the national incidence. CONCLUSIONS/SIGNIFICANCE: This study provides community based incidence rates of snakebite and envenoming for Sri Lanka. The within-country spatial variation of bites can inform healthcare decision making and highlights the limitations associated with estimates of incidence from hospital data or localized surveys. Our methods are replicable, and these models can be adapted to other geographic regions after re-estimating spatial covariance parameters for the particular region.