EVALUATION OF AN ENZYME-IMMUNOASSAY FOR THE DETECTION OF CRYPTOSPORIDIUM SPP IN STOOL SPECIMENS FROM INFANTS AND YOUNG-CHILDREN IN-FIELD STUDIES

Diagnosis of Cryptosporidium is made by the identification of oocysts in stool specimens. Screening in field studies relies mainly on acid-f ast staining followed by microscopic examination. The more sensitive i mmunofluorescent antibody (IFA) staining method is time-consuming, may involve technical difficulties, and is extremely costly as a screenin g procedure in field studies. We evaluated the diagnostic utility of a commercially available enzyme immunoassay (EIA), which detects Crypto sporidium-specific antigen, in 204 unprocessed stool specimens obtaine d from patients less than three years of age from a field study in sou thern Israel. When compared with the routine screening procedure appli ed in this field study (screening by acid-fast staining and microscopy after concentration, and confirmation of positive results by IFA), bo th the sensitivity and specificity were 98%. Of 139 specimens negative by microscopy, 13 (9.3%) were positive by the EIA. Eleven of these we re confirmed by inhibition with antibody to Cryptosporidia-specific an tigen. The EIA is an important tool for identifying Cryptosporidium in fecal specimens in field studies since it is sensitive, specific, sim ple to use, and unaffected by the presence of a preservative.