GRANULOCYTIC EHRLICHIOSIS AND MENINGITIS IN A DOG

A 4-year-old male mixed-breed dog from the Sierra Nevada mountains in California was referred because of epistaxis and signs of cervical pai n. Dermacentor variabilis ticks were found on the dog at the time of p hysical examination. Clinicopathologic abnormalities included nonregen erative anemia, thrombocytopenia, and rare intracytoplasmic morulae wi thin circulating neutrophils. Abnormalities of the CSF included pleocy tosis and intracytoplasmic morulae in approximately 9% of neutrophils. Serum antibody titers for Ehrlichia canis (40,960) and Rickettsia ric kettsii (5,120) were high, and titer for E equi (40) was moderate. Tre atment included administration of tetracycline, chloramphenicol, doxyc ycline, and prednisone. The dog had several relapses, but long-term re mission was eventually achieved. Granulocytic ehrlichiosis has previou sly been associated with anemia, thrombocytopenia, and polyarthritis i n dogs. This case suggests that granulocytic ehrlichiosis may be assoc iated with meningitis and that the organisms that cause granulocytic e hrlichiosis may have the same vector as do the spotted fever-group ric kettsiae.