Heavy infestation of Isospora belli causing severe watery diarrhea.

A 35-year-old male, positive for Human Immunodeficiency Virus (HIV) antibodies, was found to have heavy infestation by Isospora belli, leading to gastrointestinal opportunistic infection. Stool sample of the patient presenting with diarrhea of 2 months duration showed numerous oocysts of I. belli. His blood CD4 count was 85/cmm. The patient was from a slum area with poor sanitation. He was put on antimicrobial agent trimethoprim-sulfamethoxazole and was followed up. However, he died after 1 month of treatment.