Two cases of Ehrlichia canis acquired locally in Victoria.

Abstract

A 10-year-old, female desexed, Yorkshire Terrier (case 1) and a 2-year-old, female entire, Great Dane (case 2) were referred for incidentally detected anaemia, thrombocytopenia, hyperglobulinaemia, pyrexia and neutropenia, respectively. Both dogs lived in central Victoria and had no history of travel outside of the state. Both cases were presumptively diagnosed with immune-mediated disease affecting the bone marrow and treated with immunosuppressive agents (prednisolone, cyclosporine and mycophenolate, respectively). Failure of response to therapy prompted further investigation which confirmed the diagnosis of Ehrlichia. In case 1, intracytoplasmic inclusions (morulae) were observed in splenic aspirates and subsequent immunofluorescence and polymerase chain reaction (PCR) were positive for Ehrlichia canis. In case 2, serology was positive for Ehrlichia (>1:5120), but PCR was negative. Both dogs were treated with doxycycline. Case 1 was also treated with rifampicin, and case 2 received eltrombopag to stimulate bone marrow production. Case 1 remains alive 33 months following diagnosis. Case 2 had refractory neutropenia and died of suspected septic shock 11 weeks after diagnosis. To the authors' knowledge, these are the first cases of Ehrlichia canis detected in Victoria with no history of travel to endemic areas. Practicing veterinarians in this area should consider Ehrlichiosis as a differential diagnosis in dogs presenting with relevant clinical signs.