Intestinal cryptosporidiosis as an initial manifestation in a previously healthy Japanese patient with AIDS

Background. Cryptosporidium parvum infection has been recognized as one of the pathogens causing severe and persistent diarrhea in immunodeficient patients, such as those with AIDS, worldwide. However, in Japan, the frequency of this infection has been rare, except for environmental contamination through the water supply. In this communication, we describe a Japanese patient with AIDS presenting with intestinal Cryptosporidiosis as an initial manifestation. Methods. The oocysts of Cryptosporidium parvum in his stool were detected by the Ziehl-Neelsen method and electron microscopy. The antigen-specificity was proved by immunostaining, using a fluorescein isothiocyanate (FITC)-labeled monoclonal antibody and enzyme-linked immunosorbent assay (ELISA), using Cryptosporidium-specific antibody. Results. A 28-year-old Japanese homosexual man was admitted to our hospital because of severe watery diarrhea of 1-week duration. Numerous oocysts of Cryptosporidium parvum were observed in his stool. Cryptosporidium parvum antigen was detected in stool samples. Serological examinations revealed that anti-HIV-1 antibody was positive, and HIV RNA was positive at a high level. He was diagnosed as having AIDS associated with intestinal Cryptosporidiosis. The circulating CD4+ T-cell count was 152/mul. His diarrhea was not alleviated by administration of loperamide and an ordinary antibiotic agent, but ultimately resolved by the administration of the macrolide antibiotic agent, clarithromycin. Conclusions. We emphasize that the presence of Cryptosporidium parvum infection should be kept in mind in searching for pathogens causative of severe diarrhea in AIDS patients.