The developmental cycle of Caryospora bubonis Cawthorn and Stockdale 1981 (Protozoa: Eimeriidae) in the great horned owl, Bubo Virginianus (Gmelin)

Abstract

The purpose of the study was to describe some parameters of oocyst production in direct and indirect transmission studies, endogenous development, and attempts at cross transmission of Caryospora bubonis (Protozoa: Eimeriidae) of great horned owls, Bubo virginianus (Gmelin). Three great horned owls were given sporulated oocysts of C. bubonis orally. Three more great horned owls were each fed two mice which had been given sporulated oocysts of C. bubonis orally, 4 weeks previously. Feces were examined daily by flotation and daily oocyst production was estimated. One great horned owl was given sporulated oocysts of C. bubonis and killed 12 days after infection when oocysts were first detected in feces. Tissues were examined histologically. Two long-eared owls (Asio otus (Pontoppidan)) and one short-eared owl (Asio flammeus (L.)) and domestic chicks (Gallus domesticus L.) were given sporulated oocysts of C. bubonis orally and their feces examined as above. Mice were given varying doses of sporulated oocysts of C. bubonis orally and killed sequentially after infection. Tissues of mice and chickens were examined histologically.The prepatent period was 12 days, the patent period was 4–11 days long and maximal oocyst production occurred from 12 to 17 days after direct infection of great horned owls with C. bubonis. The prepatent period was shortened by 48 h in owls indirectly infected with C. bubonis in mice. Endogenous development occurred in the posterior third of the small intestine. Caryospora bubonis was not transmitted to other species of birds.