[Relative risk of infection of parasites from genus Cryptosporidium in cattle in North of Rio de Janeiro State, Brazil].

The aim of the study was to detect Cryptosporidium oocysts in calves feces throughout North of Rio de Janeiro State, Brazil, as well as to examine the risk factors involved in the animals infection. One hundred young calves on 13 dairy farms were analyzed for oocyst excretion. The samples were submitted to Ritchie and Ziehl-Neelsen modified tests, and the observation of the oocysts was made by using the optical microscope. The results obtained showed that Cryptosporidium was detected in 61% of the animals. Statistical analysis of the risk factors revealed that only three of them demonstrated a significant influence for infection: Animals bred under technical systems such as the use of milking equipment, milking cooler and farms that have water trough were more likely to be infected with the protozoan.