International Postgraduate Research Conference (IPRC)

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    Envenoming Snakebite Risk Map for Sri Lanka
    (Faculty of Graduate Studies, University of Kelaniya, Sri Lanka, 2016) Ediriweera, D.; Kasturiratne, A.; Pathmeswaran, A.; Pathmeswaran, A.; Gunawardena, N.; Jayamanne, S.; Wijayawickrama, B.; Isbister, G.; Giorgi, A.D.E.; Diggle, P.; Lalloo, D.; de Silva, J.
    Snakebite is a neglected tropical disease. Hospital based statistics often underestimate snakebite incidence because a significant proportion of victims seek traditional treatments. Since geospatial risk assessments of snakebite envenoming are rare, health care resources are distributed based on administrative boundaries rather than on a need analysis. The aim of the study was to develop a snakebite envenoming risk map for Sri Lanka. Epidemiological data was obtained from a community-based island-wide survey. The sample was distributed equally among the nine provinces. 165,665 participants living in 1118 Grama Niladhari divisions were surveyed. Model-based geostatistics was used to determine the geographical distribution of envenoming bite incidence. The Monte Carlo maximum likelihood method was used to obtain parameter estimates and plug-in spatial predictions of risk. A predictive model was developed with natural and social environmental variables to construct an estimated envenoming bite incidence map and a probability contour map (PCM) to demonstrate the spatial variation in the predictive probability that local incidence does or does not exceed national envenoming snakebite incidence (i.e. 151 per 100,000). Envenoming bite incidence had a positive association with elevation up to 195 meters above sea level, with incidence dropping at higher elevations. The incidence of envenoming was higher in the dry zone compared to intermediate and wet climatic zones and decreased with increasing population density. Developed risk maps showed substantial within-country spatial variation in envenoming bites. Conclusion: The risk maps provide useful information for healthcare decision makers to allocate resources to manage snakebite envenoming in Sri Lanka. We used replicable methods which can be adapted to other geographic regions after re-estimating spatial covariance parameters for each region of interest.
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    Individual risk factors of snakebites in Sri Lankan community
    (Faculty of Graduate Studies, University of Kelaniya, 2015) Ediriweera, E.P.D.S.; Pathmeswaran, A.; Kasturiratne, A.; Gunawardana, N.K.; Jayamanne, S.F.; de Silva, H.J.; Diggle, P.J.
    Sri Lanka has 92 identified snake species, and one of the highest snakebite incidence (SBI) rates in the world. According to hospital statistics about 37,000 patients are admitted to government hospitals annually as a result of snakebite. The aim of the present study is to identify individual risk factors for snakebite in Sri Lanka. Methodology A community-based island-wide study (―National Snakebite Study‖) was conducted in all nine provinces of Sri Lanka, with 5,000 households sampled in each province. All the residents of the selected households were included. One-year recall data for all permanent residents of that particular household was obtained regarding the experience of snakebite. Generalized linear models were used to model SBI. Individual-level gender, age, ethnicity, religion, income, education and employment were included as explanatory variables. Statistical analysis used the R programming language. Statistical significance was assessed at the 0.01 level. Results and conclusions Out of 125,391 participants, 63,604 (50.7%) were males. There was no SBI difference amongst 10-year interval age groups from 30 to 59, hence these three age groups were collapsed. High SBI was observed in the age 30-59 year group compared to age less than 20 (P<0.001), 20 to 29 (P<0.001), 60 to 69 (P<0.003) and over 70 (P<0.007), with lower SBI in the two extreme age groups. Males had higher SBI compared to females (P<0.001). Field workers had higher SBI compared to non-field workers (P<0.001). Ethnicity and income showed a significant interaction. Low income non-Sinhalese had high SBI compared to middle income (Rs. 5000-19,999, P<0.001) and high income (Rs.>20,000, P=0.001) non- Sinhalese, whereas Sinhalese had high SBI irrespective of their income status. In summary, the high risk categories for snakebites are males, field workers, 30 – 60 year individuals, Sinhalese and low income non-Sinhalese.