Canine ehrlichiosis: A review

Ehrlichiosis is a globally distributed canine vector borne disease transmitted by ticks, caused by the rickettsial bacteria Ehrlichia spp. Ehrlichiosis affects dogs and humans as well as other domestic and wild animal species. Ehrlichia spp. is gram-negative obligate intracellular bacteria with tropism for hematopoietic cells. Three different Ehrlichia species can cause canine ehrlichiosis namely E. canis, E. chaffeensis and E. ewingii. In acute cases, fever reticuloendothelial hyperplasia, generalized lymphoadenopathy, splenomegaly and thrombocytopenia are noticed. In chronic infections is characterized by marked splenomegaly, glomerulonephritis and renal failure, meningitis with associated cerebellar ataxia, depression and paresis. The disease can be diagnosed on the basis of clinical signs and can be confirmed by demonstration of the organisms (as clusters or colonies) within the cytoplasm of the mononuclear cells. Tetracyclines are the treatment of choice for rickettsial diseases. For canine ehrlichiosis, tetracycline (22 mg/kg given three times a day for 21 days.) or doxycyclines (5 mg/kg twice a day for 21 days) are recommended. The measures to be taken for this purpose include effective tick control and chemoprophylaxis of dogs in endemic area.