Molecular Evidence of a New Strain of Ehrlichia canis from South America

Blood samples from dogs with clinical signs compatible with ehrlichiosis were examined for infection of Ehrlichia canis using PCR, multiplex real-time PCR, and DNA sequencing analysis. Eleven of 25 samples were positive for a new strain of E. canis. This is the first molecular identification of E. canis infection in dogs from Peru. Ehrlichia canis is a rickettsial gram-negative bacterium re-sponsible for canine monocytic ehrlichiosis (CME) in dogs (6, 7, 19) and is mainly transmitted by ticks of the Rhipicephalus group (9, 15). E. canis has a wide distribution in the world but most frequently occurs in tropical and subtropical regions (2, 8, 11, 12, 21). Recently there have been reports of E. canis in South America (1, 6, 16, 17), including the first report of a human case of E. canis infection in Venezuela (24). The se-verity of disease depends on the host’s immune status, age, breed, and any current coinfection. Clinical manifestations may vary geographically, but in general the main clinical sign