Tissue "cysts" of Hepatozoon griseisciuri in the grey squirrel, Sciurus carolinensis: the significance of these cysts in species of Hepatozoon.

The lungs of a grey squirrel infected with Hepatozoon griseisciuri contained, in addition to typical haemogregarine schizonts, small cysts, each of which contained a single cystozoite. The presence of these cysts, which resemble those recorded in Hepatozoon species in reptiles, suggests that they may be a common feature in all Hepatozoon species and that these parasites may be transmitted by predation as well as by ingestion of infected arthropod vectors.