Live vaccine for coccidiosis utilizing coccidial sporozoites

摘要

Methods and compositions are disclosed for vaccinating warm-blooded animals against coccidiosis utilizing suspensions of excysted coccidial sporozoites in physiologically balanced medium containing water-soluble polymeric stabilizers selected from gels, gelatins, polysaccharide gums, cellulose or cellulose derivatives which extend viability or storage, additional extension of viability in storage being attained when the suspensions are finely divided and the polymeric stabilizers are hardened to form microcapsules. Prior to administration, the microcapsule is treated with a chelating agent in order to provide greater efficiency and speed of sporozoite release from the microcapsule and thus improved innoculation against oocyst challenge when compared with microcapsules which have not been treated with a chelating agent.