Eimeria separata: method for the excystation of sporozoites.

A method is described for the excystation and collection of infective sporozoites of Eimeria separata. The procedure uses conditions that resemble the in vivo environment. The first treatment of the oocysts in a 0.4% pepsin/HCl solution alters the oocyst wall, which becomes thinner. The second treatment in a 0.4% trypsin/0.75% taurocholate solution breaks the oocyst wall and sporocysts are released. A third incubation of the oocyst-sporocyst mixture in trypsin-free medium with 0.75% taurocholate and an additive of MgCl2 followed by a final incubation in RPMI medium supplemented with 1% fetal calf serum yields a sporozoite excystation rate of up to 90%.