Enterobiasis infections among Thai school children: spatial analysis using a geographic information system

Background: Enterobius vermicularis (Nematoda: Oxyuroidae) is a nematode worm, parasitic in the intestine of humans, and especially infects school children in most parts of the world. Infection occurs after ingesting drinks or food contaminated by the pinworm eggs. Samut Prakan province is located south-east of the Bangkok metropolitan area.Objective: To analyze enterobiasis infections among Thai school children in Samut Prakan province of Thailand, using a geographic information system.Methods: A total of 1,255 school children from eleven primary schools in the Samut Prakan province were drawn by stratified random sampling and tested for the presence of E. vermicularis eggs from December 2000 to March2001.Results: Diagnostic results and socioeconomic information about students and their families were integrated into a Geographic Information System (GIS) and spatially interpreted, using SavGIS programmes. Other needed environmental data, extracted from satellite images using remote sensing, was used for further analysis. Laboratory analysis revealed a 17.5% overall prevalence with 10.5% of the children having a low infection rate, 2.6% a moderate, and 4.4% a heavy infection rate. The prevalence of E. vermicularis showed geographical heterogeneity with the lowest prevalence in the provincial administrative center. Parents’ occupation was significantly correlated with the presence of infection.Conclusion: Spatial analysis can help to identify patterns of high risk for enterobiasis otherwise called oxyuriasis.