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 hematocrit. 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.

The effectiveness of 3, 5 or 7 days of albendazole for the treatment of Trichuris trichiura infection.

A randomized clinical trial was carried out to study the relationship between the duration of albendazole therapy, at 400 mg/day, and its effectiveness in the treatment of Trichuris trichiura infection. The 168 patients were treated for three (N=56), five (N=56) or seven (N=56) consecutive days. Compared with both of the shorter regimens, treatment for 7 days resulted in a significantly higher cure 'rate' and significantly greater reductions in the level of egg excretion. The advantage of using the longer (5- or 7-day) regimens was most apparent among the patients who had heavy infections (at least 1000 Trichuris eggs/g faeces) when treated. It is therefore suggested that albendazole be given for at least 3 days to those with light infections and for 5-7 days to patients with heavy infections.

A comparative trial of albendazole alone versus combination of albendazole and praziquantel for treatment of Trichuris trichiura infection.

A randomized clinical trial was conducted to compare the effectiveness of albendazole alone and albendazole combined with praziquantel in the treatment of Trichuris trichiura infection. The drug regimens consisted of single dose of albendazole 400 mg (A1, n=34), 3 days of albendazole 400 mg daily (A3, n=34), 5 days of albendazole 400 mg daily (A5, n=35), single dose of albendazole 400 mg plus praziquantel 40 mg/kg (AIP1, n=34), and 3 days of albendazole 400 mg plus praziquantel 40 mg/kg daily (A3P3, n=36). It was found that treatment with 3 or more consecutive days of albendazole with or without praziquantel resulted in a significant reduction in density of Trichuris eggs in stools while a single dose of such drug did not. Praziquantel was not shown to have synergistic or antagonistic effects with albendazole. A regimen of 400 mg of albendazole daily for 3 days was found to be the most suitable therapy for Trichuris infection.

Hymenolepis nana infection in Thai children.

Stool examination was performed on 2,083 Thai children from orphanages and primary schools. Hymenolepis nana infection was found only in children from orphanages with a prevalence of 13.12 per cent. Males had a statistically significant higher prevalence of infection than females. Most infected children were asymptomatic. In symptomatic infected children, the symptoms were mild and non-specific such as pruritus ani, abdominal pain, diarrhea, anorexia, headache, and dizziness. Praziquantel in a single oral dose of 25 mg/kg body weight was effective and well tolerated in Hymenolepis nana infected Thai children.