Detection of Cryptosporidium antigen in stool samples among diarrhoeic children.

A double antibody sandwich ELISA technique, using a chromatography purified Cryptosporidium antiserum (fractiuon 1), was applied to detect faecal antigen in children infected with Cryptosporidium suffering from diarrhoea. The assay could detect antigens in 55 out of 60 (91.7%) infected children. False positive reactions were detected in 4 children infected with E. histolytica and 2 children with Giardia. The mean level of copro-antigen was higher in children, below 10 years, than in older patients, with a highly significant difference. A significant higher mean copro-antigen level was found among children below 2 years of age who were bottle feeders when compared to those receiving breast feeding. Higher mean optical density readings was obtained in those with severe forms of diarrhoea than mild or moderate forms with statistically significant difference (P < 0.01). It was concluded that detection of Cryptosporidium antigens by ELISA technique in the stool samples is a highly sensitive (91.7%) and specific (85%) diagnostic method. It correlates well with the diarrhoea forms and the age of patients.