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 en vironmental factors affecting transmission of the organism have not be en fully elucidated. Temporal variation in the prevalence of microspor idia 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 H IV-infected individuals were examined for microsporidia spores in sout hern California. Yearly positivity rates were 8.8% in 1993, 9.7% in 19 94, 6.6% in 1995, and 2.9% in 1996. An analysis for linear trend showe d a statistically significant decrease in stool positivity rates over time (chi(2) = 81.9, P = 0.001). No significant seasonal variation in the prevalence of microsporidiosis was seen over that time period. The se results suggest the constant presence of microsporidia in the envir onment, 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 investi gation.