Possible zoonotic transmission of Cryptosporidium felis in a household.

In humans, the risk of contracting cryptosporidiosis caused by Cryptosporidium felis is considered to be relatively low, and most of the confirmed cases have been observed in immunocompromised patients. Both anthroponotic and zoonotic transmission routes have been suggested. Here, we report a case of suspected zoonotic transmission of C. felis from a cat to a human. The cat developed diarrhea several months before such symptoms were displayed by its owner, a 37-year-old immunocompetent woman. The presence of identical C. felis SSU rRNA, HSP70, and COWP gene sequences was verified in both hosts. In conclusion, it is highly probable that the cat was the initial source of infection and not the opposite. Our results show that Cryptosporidium infection can be transmitted from pets to humans and that molecular analysis is needed to confirm the identity of the oocysts.