The House Fly and Fowl Tapeworm Transmission

Abstract

That chickens may be infested with tapeworms has long been known. In the United States seven different species have been taken from fowls, and in Kansas five of these species are commonly found. Chickens kept in small inclosures are less likely to be infested than are those which have free range of the premises. It is to the latter type, the general farm chicken, that most of the writer's attention has been directed. To date the entrails of 161 fowls from the farms in the vicinity of Manhattan, Kan., have been examined. From 121, or 75.1 per cent of them, tapeworms were removed. The infestation varied from 1 to 200 or 300, and in one instance a young chick contained 443 of these parasitic worms. Fourteen to twenty-seven worms are common, and this number may make a visible effect upon the fowl, 'causing emaciation, failure to develop feathers, and general debility. On the other hand, some fowls are strong enough to harbor as many as 40 of these worms and still have a healthy appearance. The average infestation for the 121 chickens was 26.7 worms per fowl. In this connection may be cited the case of a chick hatched on May 20, 1917. Two and one-sixth months later the chick was examined and the small intestine harbored a total of 443 tapeworms. This little chick was totally without feathers, except for a few which were distributed over the top of the wings and on a narrow strip on each side of the breast. The chick weighed four and one-half ounces. Three normal chicks from the same lot, which had been kept under the same conditions (the run of the place), weighed 20, 28 and 28 ounces, respectively. It is well known that the tapeworm attaches its head or scolex to the intestinal wall of the host, that the segments which form in the region of the neck gradually develop both male and female organs, and that within a few weeks the most posterior segments become filled with eggs, or, rather, hooked embryos. At this time these gorged segments are ready to be broken from the tapeworm and passed to the exterior, where some of the embryos may be swallowed by a suitable intermediate host, in which the larval tapeworm, or bladder worm, can develop. When the intermediate host containing the bladder worm is eaten by the final host, the larval tapeworm attaches its head to the intestinal wall and develops into the adult worm. The search for suitable intermediate hosts, or the means by which tapeworms are transmitted from one chicken to another, has been a baffling problem. Two Italian investigators, Grassi and Rovelli, in the decade preceding 1892, finally found that a garden slug (Limax cinereus Lister) may be the intermediate host of the fowl tapeworm (Davainea proglottina Davaine) that is of rare occurrence in this country. Meggitt, in England, and Gutberlet and the writer, in this country, have been continuing the search much of the time during the last five years. In 1916 Gutberlet2 reported that the house fly (Musca domestica Lin.) may be the intermediate host of a chicken tapeworm, Choanotaenia infundi-