Although anemia is one of the most common clinical signs that accompany ehrlichiosis, nonregenerative anemias secondary to
bone marrow suppression appear to be more common than IMHA. Occasionally, dogs will have acute hemolytic crisis that is immune-mediated
and an associated regenerative anemia. Dogs with ehrlichiosis will frequently have concurrent thrombocytopenia and hyperglobulinemia.
Diagnoses are primarily based on serology and PCR.
Microscopic identification of morulae can be helpful when present, but microscopy is not sensitive for the diagnosis of infection.
Some species of Ehrlichia such as E. ewingii have never been cultured in vitro; consequently, no specific serologic tests exist. PCR and microscopy are the only tests
available for the diagnosis of E. ewingii infection. Treatment with doxycycline (10 mg/kg/PO daily) for three weeks is the treatment of choice for canine ehrlichiosis.
IMHA appears to be a rare complication of the other rickettsial infections in dogs.
Closer look at bacterial diseases
A few bacterial diseases are associated with anemia in dogs. Definitive associations between these diseases and IMHA have
not been made. Candidatus Mycoplasma haemocanis (Haemobartonella canis) and at least one other species of haemoplasma have been identified in anemic dogs. It does not appear, however, that these
species are virulent pathogens in the absence of concurrent diseases.
Bartonella species are emerging as an important cause of disease in dogs. While endocarditis remains the primary clinical
disease recognized, there is a growing body of evidence that bartonellosis is associated with IMHA in dogs. Leptospirosis
has been associated with IMHA in dogs; however, renal and hepatic failure continue to be the primary clinical problems that
need to be addressed in dogs with clinical leptospirosis.
Dr. Hoskins is owner of DocuTech Services. He is a diplomate of the American College of Veterinary Internal Medicine with
specialities in small animal pediatrics. He can be reached at (225) 955-3252, fax: (214) 242-2200 or e-mail: