ENVIRONMENTAL SOURCES OF CRYPTOSPORIDIUM IN AN URBAN SLUM IN NORTHEASTERN BRAZIL

Cryptosporidium is an important cause of diarrheal disease in children world-wide. To elucidate the environmental sources of this parasite, we selected an urban slum in Fortaleza, Brazil, a community with a kno wn high incidence of cryptosporidiosis, and examined both stool smears from household animals (n = 127) and filtrates from local water sourc es (n = 18) for Cryptosporidium oocysts. Because previous work in this community has demonstrated the seasonal nature of human infection wit h Cryptosporidium, collections were made separately for the dry and ra iny seasons. Of the 64 stools collected during the dry season (Septemb er-December 1990), four (6.3%) were positive by acid-fast staining for Cryptosporidium. Of the 63 rainy season samples (March-May 1991), nin e (14.3%) were positive. Overall, oocysts were detected in 13 (10.2%) of 127 animal stool samples. Freshwater samples were obtained from a v ariety of sources including open and closed wells, and running city wa ter and then processed. Four of 18 samples (22.2%), including a sample from city water were positive by at least one of two staining techniq ues (acid-fast and immunofluorescence). In summary, animals may serve as a reservoir of Cryptosporidium, with potential for the contaminatio n of immediate household water sources. These findings may help to exp lain the high incidence of cryptosporidiosis among infants in this imp overished community.