Figure 1.
Eimeria tenella life-cycle. Sporogony occurs in the environment, whereas schizogony and gamogony occur in the chicken digestive tract. For the wild-type strain, three rounds of schizogony produce first-, second-, and third-generation merozoites. NSO, non-sporulated oocysts, SO sporulated oocysts, eSPZ extracellular sporozoites, iSPZ intracellular sporozoites, ImmSCHZ immature schizonts, MatSCHZ mature schizonts, MI first-generation merozoites, MII second-generation merozoites, and MIII third-generation merozoites.