Albendazole therapy for Microsporidium diarrhea in immunocompetent Costa Rican children.

Background: Microsporidia comprise a large group of obligate intracellular parasites. Although several species have emerged as opportunistic agents in immunocompromised patients, cases have also been reported in immunocompetent patients.

Methods: During 21 months, we conducted a randomized, open label study in 200 children hospitalized with Microsporidium subacute diarrhea. Patients had prolonged, nonbloody, nonmucoid diarrhea, with > or =10 bowel movements/day for >10 days. Patients had negative rotavirus tests, bacterial stool cultures and sugar reductive tests in feces. Stool examinations to rule out Giardia intestinalis and intestinal nematodes were performed. Microsporidium was identified by light microscopy in stool specimens stained with Giemsa and Weber techniques. One hundred patients received oral albendazole (15 mg/kg/day twice a day for 7 days) and 100 patients received only supportive therapy.

Results: Both groups were comparable regarding gender, age, clinical evolution and weight. Median (range) age was 24 (6-36) months. All children had abdominal pain, nausea, vomiting and anorexia. The primary endpoint, defined as clinical improvement within 48 h of initial therapy, occurred in 95 and 30% of the albendazole-treated and untreated patients, respectively (P < 0.05). There was a significant decrease in stool frequency, reduction of clinical findings and decrease in Microsporidium parasites in stool specimens of children treated with albendazole compared with the untreated group. Median (range) duration of diarrhea was 5 (3-7) days in albendazole-treated patients versus 10 (8-15) days in untreated patients (P < 0.05).

Conclusion: Albendazole therapy was effective in improving the clinical manifestations and decreasing the duration of the illness of children with diarrhea caused by Microsporidium.