Evaluation for detection of Cryptosporidium oocysts in diarrheal feces of calves.

For the detection of Cryptosporidium oocysts, fecal samples were collected from 201 calves which showed diarrhea. Among the 201 samples, 29 samples (14.4%) were positive for Cryptosporidium spp. by the DMSO-modified acid-fast stain (MAFS), 23 samples (11.4%) were positive by commercial kit (Meridian Diagnostics, Cincinnati, Ohio) and 23 by the indirect immunofluorescence antibody (IFA) assay employing the monoclonal antibody (mAb C6). When tested by both IFA and MAFS, 20 fecal samples were positive for Cryptosporidium oocysts whereas 169 fecal samples were negative. If the MAFS is considered a standard method for oocyst detection, the IFA showed 69% of sensitivity and 98% of specificity. When tested by both IFA and commercial kit, 22 fecal samples were positive for Cryptosporidium oocysts while 177 samples were negative. One sample tested by IFA was found to be false negative, when compared with the results by commercial kit. The sensitivity of IFA was calculated as high as 96%; the specificity as 99% and the predictive value was also 99%. In the present study, IFA employing the mAb C6 revealed that 23 samples (11.4%) were positive among the 201 calves showing diarrhea. Of 23 IFA positive samples, 4 samples (5%) showed cryptosporidial oocysts more than 10(5) OPG. Therefore, it is concluded that the calves showing cryptosporidial oocysts more than 10(5) OPG in the feces were highly associated with clinical cryptosporidiosis.