Ooocyst production, late-stage merogony, gametogony, and cross-transmission studies of Eimeria bubonis (Protozoa: Eimeriidae) of the great horned owl, Bubo virginianus

Three B. virginianus were each inoculated orally with 1.0 X 104 sporulated oocysts of E. bubonis and 3 were each fed 2 mice which had been previously intubated with sporulated oocysts of E. bubonis. In the directly infected owls the prepatent period was 5 to 6 days and the patent period was 4 and 6 days in 2 owls and 40 days in the 3rd; maximum oocyst output (7.0 X 105 oocysts) occurred 6 to 7 days after inoculation. Examination of one B. virginianus 5.5 days after oral inoculation with 2.25 X 105 sporulated oocysts revealed endogenous stages of E. bubonis distal to the nuclei of villar epithelial cells of the anterior half of the small intestine; no macroscopic or microscopic lesions were present. Domestic chicks orally inoculated with E. bubonis did not pass oocysts in the faeces. Examination of mice up to 12 weeks after intubation with sporulated oocysts revealed phlebitis associated with pyogranulomas in the liver..