Dr. Adam J. Birkenheuer from the University of Pennsylvania School of Veterinary Medicine and his associates detected a large unnamed Babesia species in a dog suffering from lymphoma. Since it was unknown whether this was an underrecognized pathogen, he and his team performed a retrospective case review. For their review, they collected data by contacting attending clinicians and sighting medical records. The 18S rRNA genes of Babesia sp. were amplified and sequenced in a diagnostic laboratory. Birkenheuer identified seven immunocompromised dogs from which the specific Babesia was determined with the help of 18S rRNA gene sequencing.

His team looked at the treatment protocol of the affected dogs. Six of the seven dogs had been splenectomized, the remaining dog received oncolytic drugs. Nearly all dogs (6/7) were lethargic and anorexic. About half of the dogs suffered from fever (4) and pigmenturia (3). Laboratory findings demonstrated mild anemia in all dogs and severe thrombocytopenia in six. PCR assays used to detect Babesia sensu stricto species were all positive, however the PCR assays for Babesia canis and Babesia gibsoni were negative in all dogs. Furthermore, cross-reactive antibodies against other Babesia spp. were not always detectable, the authors find. Five dogs received treatment with imidocarb dipropionate and one dog received atovaquone/azithromycin, with some favorable response. The remaining dog was left untreated, and remained a clinically stable carrier.

The authors therefore conclude that dogs with pigmenturia, anemia and thrombocytopenia should be tested for Babesia sp. by PCR as serology could not sufficiently demonstrate a reliable diagnosis of this Babesia sp. Asplenia, chemotherapy, or both might pose a risk for persistent infection, illness or both, Birkenheuer and his team wrote.

References

• JVIM 24(1):127 - 131