Studies on the sheep tapeworm, Moniezia expansa Rudolphi, 1810, in New Zealand

Abstract

The anatomy of Moniezia expansa is described, including the external features, segmentation of the strobila, the nature of the body tissues, the excretory system, and the anatomy and development of the reproductive system. Some aspects of infestation of the definitive host by Moniezia are discussed on the basis of results obtained by dissecting the intestines of eighty-five lambs. Percentage infections of lambs during the season, levels of the infestation and longevity of the strobilar stage were studied. An infection of up to 100% of the samples examined was found, decreasing during the summer until, six to eight months after the first exposure of the host to the parasite, all gravid infestations had been eliminated from the lambs. The pattern of release of proglottides from an infested lamb was studied for seventeen days, and some observations were made of the release of eggs from gravid proglottides. The intermediate host of Moniezia, an oribatid mite, was isolated from soil samples taken from an infected paddock, and was tentatively identified as belonging to the genus Grandjeanobates of the family Scheloribatidae. 2.6% of the host mites were infested with cysticercoids of the tapeworm. Investigations into the movements of the intermediate host on the pasture during the twenty-four hour period showed that the greatest number of mites were on the grass itself, rather than in the grass mat, or in the top layer of soil, at 8 a.m., a time when all the lambs were grazing steadily.