Babesia gibsoni is a blood parasite that appears to be emerging as an infectious disease of dogs in the United States. It is generally believed that the mechanism of transmission involves ixodid ticks, but transmission may also occur by direct blood contamination, such as that which could occur in fights or tail dockings.

A 21/2-year-old German shepherd had complications during ovariohysterectomy and was given a blood transfusion as part of treatment. The anemia continued to worsen despite various treatments. Laboratory testing for tick-borne pathogens revealed a seroreaction to Babesia canis and Borrelia burgdorferi. Small piroplasms identified as B. gibsoni were identified on blood smears. Polymerase chain reaction (PCR) analysis confirmed the presence of B. gibsoni. The donor also had antibody titer to Babesia species and PCR assay identifying B. gibsoni, but no organisms were seen on blood smears.

This is the first report of a dog from Michigan with B. gibsoni. The dog is clinically normal but still has parasitemia despite treatment with imidocarb (6 mg/kg) for more than 11 months. There are no reports of successful elimination of B. gibsoni infection in dogs.

COMMENTARY: Blood donor dogs should be screened for Babesia infection; such screening should include serologic, microscopic, and molecular testing.

Transfusion-associated Babesia gibsoni infection in a dog. Stegeman JR, Birkenheuer AJ, Kruger JM, Breitschwerdt EB. JAVMA 222:959-963, 2003.