Recovery of Cyclospora cayetanensis among asymptomatic rural Thai schoolchildren

Objective: To obtain the prevalence with clinical symptoms of Cyclospora cayetanensis (C. cayetanensis), a coccidian protozoan parasite, in Thailand which is the cause of an intestinal infection characterized by sporadic-to-frequent explosive diarrhea. Methods: In a field survey conducted by the Faculty of Tropical Medicine, Mahidol University, as part of the existing parasite-control program, a total of 2 540 faecal samples from villagers in Nan Province, Thailand, were collected and examined to determine the prevalence and clinical characteristics of parasitic infections. Results: Twelve cases of C. cayetanensis infection were found during faecal examination of schoolchildren aged 5-12 years. None exhibited obvious clinical symptoms, especially evidence of diarrhea; 5 of 12 had loose faeces, one reported frequent symptoms of abdominal discomfort, and another had pale conjunctiva with low homatocrit. The children were generally asymptomatic. Conclusions: This finding confirms a public-health issue with potentially serious consequences whereby children can be exposed to an environment contaminated with food-and water-borne transmitted oocysts, and can hence become infected with C. cayetanensis.