TKICHINOSIS IN SWINE AND ITS RELATIONSHIP TO 

 PUBLIC HEALTH^ 



By Benjamin Schwaktz, 

 Chief, Zoological Division, Bureau of Animal Industry, U. S. Department of 



Agriculture 



' INTRODUCTION 



Trichinosis is a disease of human beings, swine, and other animals, 

 and is of interest, therefore, to physicians, veterinarians, and public 

 health and livestock sanitary officials and workers. This disease 

 concerns also farmers and other swine growers because it is contracted 

 by hogs as a result of certain swine husbandry practices. The meat 

 and meat-packing industries are also vitally ajffected by the presence 

 of trichinae in hogs, the transmission of these parasites to human 

 beings through the consumption of raw or inadequately cooked or 

 processed pork resulting in lawsuits for the recovery of damages on 

 account of illness or death. This paper discusses trichinosis from 

 the biological standpoint and as a problem concerning public health, 

 livestock sanitation, veterinary medicine, and the meat and meat- 

 packing industries, and outlines methods of controlling this important 

 human and animal disease. 



THE DISCOVERY OF TRICHINAE AND THE DEMONSTRATION OF THEIR 



LIFE CYCLE 



Trichinae were first discovered in swine by Joseph Leidy, an 

 American physician and naturalist. Leidy communicated his dis- 

 covery to the Philadelphia Academy of Natural Sciences in October 

 1846; the published report (1) ^ of this communication prepared by 

 the Academy's secretary is as follows : 



Dr. Leidy stated that he had lately detected the existence of an Entozoon in 

 the superficial part of the extensor muscles of the thigh of a hog. The En- 

 tozoon is a minute, coiled worm, contained in a cyst. The cysts are numerous, 

 white, oval in shape, of a gritty nature, and between the 30th and 40th of an 

 inch in length. 



* Reprinted by permission from the Journal of the American Veterinary Medical Asso- 

 ciation, vol-. 92. n. 8:- 45, No; 3, pp. 317-337, March 1938, with slight revision and 

 amplification by the author (August 1939). ■ 



'Numbers in parentheses refer to list at end of article. - • • 



413 



