Hepatozoonosis

Abstract

Canine hepatozoonosis is a vector-borne disease caused by apicomplexan protozoa of the genus Hepatozoon. Dogs may be infected by two Hepatozoon species, namely, Hepatozoon americanum and Hepatozoon canis. The first species is considered to be restricted to North America, whereas the second has a cosmopolitan distribution. Recently, feline infection by Hepatozoon felis showed to be prevalent in some cat populations worldwide. Hepatozoon infection typically occurs when a susceptible animal ingests a tick vector harboring mature oocysts with sporozoites, even if intrauterine transmission has been described for both H. canis and H. americanum for which also carnivorism of the intermediate host was suggested. While H. canis meronts develop in the lymphatic organs (e.g., spleen and lymph nodes), bone marrow, and liver, mostly causing mild disease, H. americanum may cause debilitating conditions, associated with musculoskeletal pain. The diagnosis of canine hepatozoonosis is mainly based on the presence of compatible clinical signs and the cytological or molecular detection of gamonts in blood samples. Several therapeutic protocols have been proposed, but data on the treatment of the disease are still incipient. Currently, no vaccine is available for the prevention of canine hepatozoonosis, and therefore the control of this infection should rely on the control of ticks.