ABSTRACT
Cryptosporidium is a globally distributed protozoan parasite and one of the most common causes of infection and diarrhea in humans and cattle. The aim of the present study was to determine the species of Cryptosporidium among cattle with diarrhea by a nested PCR-RFLP technique at Cryptosporidium oocyst wall protein [COWP]. Fecal samples from 158 calves aged 1-20 weeks were collected from 10 dairy farms in Qazvin province, Iran. Initial identification of Cryptosporidium was carried out by Zeihl-Neelsen acid-fast staining method of stool samples. DNA was extracted from 26 [16.45 %] positive microscopically samples and Cryptosporidium genotypes were determined. Cryptosporidium parvum were identified in 80.8% of the positive samples and, Cryptosporidium andersoni in 19.2%. In conclusion the use of COWP primers could be sensitive enough to conduct a routine detection study. The nested PCR method using the COWP gene sequence can be an alternative diagnostic method to identify infected with Cryptosporidium and its genetic diversity