Eimeria spp. from the chicken: from merozoites to oocysts in embryonated eggs.

Merozoites of 5 species of Eimeria from the chicken were recovered from this host and inoculated into the allantoic cavity of embryonated chicken eggs. The merozoites developed into sexual stages in the chorio-allantoic membranes, and oocysts of all the species which were tested - E. acervulina, E. brunetti, E. maxima, E. necatrix and E. praecox - were recovered. Many of the oocysts of E. maxima and E. necatrix, and a few of those of E. brunetti, sporulated and were found to be infective for chickens.