At some point, some merozoites begin the sexual phase of the life cycle, being micro and macro-gametes. Fertilization occurs and a zygote is produced within the host cells. In all instances, the number of asexual cycles is pre-determined. Pathogenesis is related to intestinal cell distruction. Fever is not common unless secondary infection occurs.
Bloody diarrhea is common in some infections with a resulting anemia.
In general, the disease caused by coccidia varies not only with the state of the host, but with the species of coccidia, the degree of parasitism, and the site of infection. In addition to clinical signs associated withthe intestinalcell distruction, vague related signs may olso occur such as rough hair coat, poor weight gains or weight loss, and emaciation. In severly infected animals, death may occur and inothers, central nervous system disorders may be notable. Diagnosis is dependent on microscopic detection of oocysts in feces or by identification of endogenous stages obtained by scrapings of intestinal cells. Treatment usually involves sulfonamides, nitrofurazone, or amprolium.