Abstract
Isospora belli, an opportunistic coccidia, has recently been reported as a cause of severe diarrhoea in AIDS patients. We report a 40-year-old female, who presented with prolonged watery diarrhoea and weight loss. She had received blood transfusions in 1985 for a fractured femur. She was positive for human immunodeficiency virus antibodies. Her cd4 (helper) cells were markedly diminished. Isospora belli oocysts were repeatedly recovered from her stool specimens. She initially responded to trimethoprim-sulphamethoxazole therapy. However, eventually she expired. Patients with severe, chronic and intractable diarrhoea should be investigated for Isospora belli infection and underlying AIDS.