THE COMPARATIVE BIOLOGY AND MORPHOLOGY OF TAENIA OVIS AND TAENIA KRABBEI, WITH OBSERVATIONS ON THE DEVELOPMENT OF T. OVIS IN DOMESTIC SHEEP

Abstract

The geographic distribution of infections of skeletal muscle and cardiac cysticerci, possibly T. krabbei, in North American Cervidae is related where pertinent to the geographic distribution of T. ovis in domestic sheep. Experiments show that T. krabbei and T. ovis are biologically distinct but morphologically indistinguishable.The T. ovis embryo migrates through the muscle tissue forming a streak when only a few days old. Where the host response is not inhibitory, complete differentiation and rostellar hook development occur about 56 days after exposure. Many parasites are destroyed by the host as differentiating embryos, before rostellar hooks have begun to develop, during hook development, but only rarely after the cyst is differentiated completely. Viable cysts are surrounded by only a thin fibrous wall. Dead and viable cysts occur non-systematically and show no relationship to any particular muscles, body area, or body system.