Often the disease can be fatal before blood stages could be diagnosed. Once the parasite appears in the peripheral blood, the main pathogenic phase of the disease has already passed and primary lesions are healing up.
Hepatozoon canis infection is usually diagnosed by microscopic detection of intracellular H. canis in stained blood smears. They are found in the cytoplasm of neutrophils and monocytes, have an ellipsoidal, brick-like shape and are about 11 x 4 µm in size.
H. americanum is rare in the blood and parasitemia usually does not exceed 0.1%. Confirmation of H. americanum infection is commonly performed by muscle biopsy and demonstration of parasites in cysts or granulomas.
Serological tests for H. canis and H. americanum infection have been developed for the detection of anti-H. canis and anti-H. americanum antibodies.
- Baneth G: Hepatozoonosis. In: Arthropod-borne Diseases. 2002, Sci. Proc. BSAVA Congress, Birmingham, pp 187-9