CLINICAL AND EPIDEMIOLOGIC FEATURES OF A MASSIVE WATERBORNE OUTBREAK OF CRYPTOSPORIDIOSIS IN PERSONS WITH HIV-INFECTION

During March and April 1993, a massive outbreak of Cryptosporidium inf ection resulted from contamination of the public water supply in Milwa ukee, Wisconsin. The health impact of this outbreak in HIV-infected pe rsons was unknown but was perceived as severe. We surveyed HIV-infecte d persons who resided in the greater Milwaukee area to examine the acu te health impact of cryptosporidiosis on this population. Data from a random-digit dialing survey in the general population residing in the same area were used for comparison. The attack rate of watery diarrhea suggestive of cryptosporidiosis was lower in HIV-infected persons (32 %) than in the general population (51%). There was no significant diff erence in attack rate in HIV-infected persons based on CD4(+) T-lympho cyte count. In persons with watery diarrhea, HIV-infected persons were more likely to experience cough (42%), fever (52%), and dehydration ( 55%). In HIV-infected persons with watery diarrhea, persons with CD4() T-lymphocyte counts <200/mu l had longer duration of diarrhea and we re more likely to seek medical attention and be hospitalized. During t his massive waterborne outbreak, HIV-infected persons were not more li kely to experience symptomatic Cryptosporidium infection than the gene ral population. However, once infected, the duration and severity of i llness was greater in HIV-infected persons, especially if the CD4(+) T -lymphocyte count was <200/mu l.