Cryptosporidiosis in HIV infected persons: Prevalence in a New York City population

A prospective study of 137 human immunodeficiency virus (HIV)-infected outpatients was conducted at a New York City clinic to determine the seroprevalence of anticryptosporidial antibody, and the prevalence of cryptosporidial infection. In addition, the potential risk factors for cryptosporidial infection in an HIV-infected population in an urban environment were also investigated. A seroprevalence of 20.3% was found for anti- Cryptosporidium antibody within the urban HIV-positive population studied. This prevalence is within the range that has been established for immunocompetent populations in the United States and in Europe. It indicates that a significant proportion of the population has had cryptospordial infection in the past. Longitudinal studies are needed to establish whether cryptosporidiosis is a reactivation of past infection in the immunocompromised host. Stool samples were examined for ova and parasites and acid-fast stained for detection of cryptosporidial oocysts. Previously unrecognized cryptosporidial infection was found in 3.6% of the study population. This prevalence is similar to that reported for an HIV-infected inner city population in Los Angeles. The numbers obtained in this study may be an underestimate of the true prevalence of cryptosporidial infection, because serial stool samples were not examined and because there is evidence that the commonly used acid-fast method for identification of Cryptosporidium in stool is insensitive. There was no correlation between risk factors for cryptosporidial infection and either stool or seropositivity.