Predictors for the risk of hookworm infection: experience from endemic villages in southern Thailand.

To assess the role of defaecation pattern in predicting the level of risk for hookworm infection in southern Thailand, 4 villages in different geographical settings in endemic areas were studied. Close observation and stool examinations for hookworm were carried out. The first village was used for exploring the risk factors for hookworm infection. The resultant statistical model was then tested using the other 3 villages. Only 23-40% of the sample regularly defaecated in a latrine. The pattern of defaecation did not differ between the sexes, but was associated with age and site of residence. In the first village, the following variables were not statistically significant: sex, age, level of past education, household income, having neighbouring houses within 20 m, latrine availability, site of defaecation. The only statistically significant protective factor was shoe wearing, which showed an exposure-outcome severity relationship. Similar results were obtained in the other 3 villages. These results refute the protective effect of latrine use on the individual user, who may still get infection from the faeces of other community members. Promotion of shoe-wearing, which provides individual protection, should be an important supplementary strategy for hookworm control programmes in such areas.