Eimeria acervulina infections from each of the four sporocysts of a single oocyst.

Oocysts were found in all four birds each infected with one of the four sporocysts of a single oocyst of Eimeria acervulina and in three of the four birds infected with single sporocysts from two other oocysts. Possible use of these infections for genetic studies was discussed. An efficient method for collecting fecal material containing sometimes rather low levels of oocysts was also described.