Possible zoonotic transmission of Cryptosporidium felis in a household

Abstract

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. M ost cases of human cryptosporidiosis are caused by either Cryptosporidium hominis or Cryptospo-ridium parvum, the latter of which also infects a number of other mammals, mainly calves and lambs, and is thus responsible for most zoonotic infections in humans. The use of molecular methods has revealed that humans can be infected with several other zoonotic Cryptosporidium species as well, including Cryptosporidium meleagridis, Cry-ptosporidium cuniculus, Cryptosporidium ubiquitum, Crypto-sporidium canis, and Cryptosporidium felis (1Á3), although recent findings suggest that some of these infections arise through anthroponotic rather than zoonotic transmission (1, 4). Hence, the role of companion animals such as dogs and cats in transmission of human cryptosporidiosis is not clear. Here, we investigated a case of suspected zoonotic transmis-sion of C. felis between a cat and a human in Sweden.