Canine monocytic ehrlichiosis: An update

Canine monocytic ehrlichiosis, an important tick-borne disease of dogs and other canids, is reported in many parts of the world. This article considers the disease in light of its background and history, cause, epidemiology, pathogenesis, signalment, clinical findings, hematologic findings, biochemical findings, diagnosis, treatment, prognosis, and prevention. Canine monocytic ehrlichiosis can be manifested by a wide variety of clinical signs; the predominant signs are depression, lethargy, mild weight loss, anorexia, pyrexia, lymphadenomegaly, splenomegaly, and bleeding tendencies. Thrombocytopenia is the most common and consistent hematologic finding in all stages of canine monocytic ehrlichiosis. Anemia and leukopenia may occur during the acute and chronic phases. Pronounced pancytopenia is the hall-mark of the severe chronic phase and results from hypocellular bone marrow. The principal biochemical abnormalities include hypoalbuminemia, hyperglobulinemia, and hypergammaglobulinemia. Long-term treatment with doxycycline and imidocarb dipropionate is recommended. Clinicians should be aware of the possibility of coinfections with other tick-borne parasites; such coinfections are common.