Modification of the clinical course of intestinal microsporidiosis in acquired immunodeficiency syndrome patients by immune status and anti-human immunodeficiency virus therapy.

The clinical course of 37 Enterocytozoon bieneusi-infected acquired immunodeficiency syndrome patients with diarrhea was studied. Parasite clearance was seen in 15 patients (40.5%). Clearance of E. bieneusi resulted in a 25-100% reduction in episodes of diarrhea, suggesting that microsporidia are true pathogens. Univariate and multivariate proportional hazards analyses revealed that peripheral blood CD4 cell counts > or = 100/mm3, the use of two or more antiretroviral medications, and use of a protease inhibitor were statistically associated with decreased time to clearance of E. bieneusi. Specific anti-microsporidial therapy (albendazole) was not associated with parasite eradication. Factors related to immunocompetence and human immunodeficiency virus suppression appeared to be important in the clearance of E. bieneusi.

Examination of the prevalence and seasonal variation of intestinal microsporidiosis in the stools of persons with chronic diarrhea and human immunodeficiency virus infection.

The epidemiology of human microsporidiosis is poorly understood and environmental factors affecting transmission of the organism have not been fully elucidated. Temporal variation in the prevalence of microsporidia in the stool of patients with human immunodeficiency virus (HIV) infection and diarrhea was studied to evaluate the role of water-borne transmission. From January 1993 to December 1996, 8,439 stools from HIV-infected individuals were examined for microsporidia spores in southern California. Yearly positivity rates were 8.8% in 1993, 9.7% in 1994, 6.6% in 1995, and 2.9% in 1996. An analysis for linear trend showed a statistically significant decrease in stool positivity rates over time (chi2 = 81.9, P = 0.001). No significant seasonal variation in the prevalence of microsporidiosis was seen over that time period. These results suggest the constant presence of microsporidia in the environment, rather than a seasonal association with recreational water use or seasonal contamination of the water supply, and a real decrease in yearly prevalence of microsporidia related diarrhea. Factors related to a progressive decrease in prevalence are subjects of future investigation.