Figure 1. E. vermiformis life cycle.

A single sporulated oocyst can initiate an infection when swallowed by its respective host, the mouse. Each mature oocyst holds four sporocysts, each sporocyst gives rise to two sporozoites, which can infect the enterocytes. Inside the host cell, the parasite develops via trophozoite and schizont stages into merozoites. Merozoites can re-infect the epithelial cells and start a new cycle. Eimeria typically undergoes three rounds of asexual multiplication whereupon merozoites give rise to gametes. Male and female gametes can fuse to form an oocyst, protected by a multi-layered cell wall making them highly resistant to environmental pressures. These oocysts shed with the feces. Unsporulated oocysts undergo sporulation upon contact with oxygen and moisture, undergoing meiosis, which takes between 2 to 7 days.