Lack of evidence for perinatal transmission of Cytauxzoon felis in domestic cats.

Cytauxzoon felis is a hemoprotozoan parasite of cats capable of causing severe, often fatal disease during acute infection, but cats that survive the acute stage of disease become chronic carriers. These otherwise healthy carriers are capable of transmitting the infection to other cats via the bite of a vector tick. A variety of other hematoprotozoan parasites are capable of vertical transmission from mother to offspring. If this were possible for C. felis, it could be an important part of the explanation for the apparent emergence of this disease with an increased incidence in an expanding geographic area. We investigated the possibility of perinatal transmission of C. felis from chronically infected cats to their offspring. Two queens produced a total of 14 healthy kittens in three litters. All kittens tested negative for C. felis by microscopic slide review and PCR until they were adopted to private homes at approximately 12 weeks of age. While this does not rule out the possibility of perinatal transmission, it is unlikely to be a common phenomenon.