[Detection of fecal Cryptosporidium parvum antigens using an ELISA technique]

ELISA techniques using monoclonal antibodies have been recently developed for the detection of Cryptosporidium parvum fecal antigens. The aim of this work was to compare the yield of these ELISA techniques with Ziehl-Nielsen and Safranin stains in formaldehyde-salt fixed samples. One hundred five fecal samples of patients with acute diarrhea were studied. Forty-seven samples did not contain Cryptosporidium and ELISA was negative. Also, ELISA was positive in 52 or 58 samples that contained Cryptosporidium (89.6%); the samples with false negative results contained scanty oocysts. Seven intensely positive Paf-fixed stool samples from AIDS patients with chronic diarrhea, were not reactive to ELISA. There was a good correlation between visually and mechanically read samples and there were no false positives. It is concluded that ELISA cannot be used in Paf-fixed samples and has a lower sensitivity that the stained commonly used for the diagnosis of cryptosporidiosis.