Rickettsial Disease

18 Aug Rickettsial Disease

A blood smear from a 10-year-old, spayed female, mixed breed dog was evaluated.  The patient was febrile, reluctant to jump in and out of the car, and hyporexic.  Approximately 25% of neutrophils contained rickettsial morulae (see figure for example) that were irregularly round, 1-2 microns, grey with a granular to punctate appearance.  A moderate thrombocytopenia and mild, non-regenerative anemia were also present.    

Although additional testing is needed for speciation of the organism, Erhlichia ewingii and Anaplasma phagocytophilum are typically found in neutrophils while E. canis, if found in peripheral blood, is typically observed in monocytes.