New Intermediary Insect Host Records for the Giant Thorn-Headed Worm of Swine. Phyllophaga rugosa an Intermediary Host, and the Adult Beetle a Carrier.*

Abstract

The giant thorn-headed worm, Macracanthorhynchus hirudinaceus (Pallas) Travassos, is a serious, a very common, and a widely distributed intestinal parasite of swine. This parasite is provided with a retractile rostrum, the so-called “head,” which is armed with recurved, thorn-like spines or hooks. The worm inhabits the small intestine of the pig, where it anchors itself by working the spiny “head” deeply into the tissues of the intestinal wall. The resulting irritation causes an annular proliferation about the point of attachment, which is marked on the outer surface of the intestine by a firm, somewhat elevated mass of hypertrophied tissue, from six to ten millimeters in diameter. The lesion so produced may develop into an abscess, and may even result in a perforation of the intestinal wall.