Abstract

AIM--To identify and describe electron microscopic changes occurring in Enterocytozoon bieneusi in patients treated with albendazole. METHODS--Eighteen HIV seropositive patients with E bieneusi infection of the small intestine were treated with albendazole 400 mg twice a day for one month. Duodenal biopsy specimens obtained before and at the end of treatment were examined electron microscopically by a pathologist who was unaware of the clinical response. A semiquantitative assessment of the parasite load and description of the parasite morphology was made. RESULTS--A complete resolution of diarrhoea occurred in nine patients and a further three had a greater than 50% reduction in baseline stool frequency or volume. Three of the non-responders were also infected with cryptosporidium. There was a reduction in parasite load in those responding to treatment and an increase in abnormal forms in both responders and non-responders. CONCLUSION--The clinical response to albendazole treatment seen in some patients with small intestine microsporidiosis may be due to damage to the developmental stages, causing a partial inhibition of parasite reproduction.