Arrested development in Eimeria nieschulzi (Apicomplexa: Eimeriina): results of single infections.

Arrested development of Eimeria nieschulzi in the rat was investigated by feeding tissues of infected rats to coccidia-free rats. Intestinal tissue of 33 infected rats was fed on days 9, 10, 11, 14, 17, 21, and 28 PI to 43 uninfected recipients. Eight recipients, which represent 24.2% of the donors, later showed infection. Infections were retained for as long as 21 days after the initial infection. A prepatent period of 6 to 7 days in the recipients allowed the inference that the retained stage was the sporozoite. No infections were observed in 14 recipients fed spleen, lymph nodes, liver, or lung of infected animals.