ABSTRACT
A survey of Strongyloides stercoralis infection was conducted in 11 southern provinces of Thailand by agar-plate culture technique. A total of 1,308 stool samples were collected by 30-cluster sampling technique during July-August 2007. The results revealed that the overall prevalence of S. stercoralis in the study areas was 20.6% and the intensity was mostly low. The highest infection rate was found in Phatthalung Province (29.9%), and the lowest in Phuket Province (7.5%). The highest positive finding was among the group aged 60 years and over (28.5%), and the rate of infection was comparatively high among males (25.4%). At cluster or village level, the highest infection rate was 51.9% in Ban Don Gun Village, Nakhon Si Thammarat Province, and the lowest 2.3% in Ban Yang Mark Village, Trang Province. The results of the surveillance showed that a majority of the population had high trongyloidiasis-related risk behaviors–poor hygiene and inappropriate footwear behaviors, such as wearing open sandals, so that 89.9% had an enhanced risk of infection, and only 22.2% wore casual shoes. Only 24.1% habitually wore boots when they worked in the paddy field, with the remaining 75.9% at higher risk of infection. However, it was also instructive to learn that the proportion of people who routinely washed fresh vegetables thoroughly before eating, to prevent larval contamination, was quite high (94.4%). Almost all (96.0%) of the people habitually defecated in a sanitary latrine when at home; however, when they worked in the field, the rate was far lower, at only 37.7%. It was interesting to find that 11.6% of the people habitually defecated outside a latrine, on the ground, while about 50.1% sometimes defecated on the ground, which would also result in a higher risk of the spread of disease. The information obtained from the behavioral survey also showed that high-level risk behaviors for the transmission of strongyloidiasis in southern Thailand, where potential hosts do exist, higher than the previously reported data about the prevalence of S. stercoralis infection. Proactive health education and empowerment of the community are recommended to control strongyloidiasis, and so prevent health problems among the people in such areas.