CHAPTER XVI 

 TRICHINA WORMS 



Of quite a different nature from other intestinal parasites is 

 the trichina worm, Trichinella spiralis. As far as the injurious- 

 ness of its presence in the intestine is concerned it is much less 

 serious than many of the other intestinal worms, since its length 

 of life as an adult is relatively short. The serious and often 

 fatal results of trichina infection are due to the peculiar life 

 history of the worm and are concerned with the offspring of the 

 infecting worms and not with these worms themselves. 



There can be little doubt but that this worm, with the pork 

 tapeworm as an accomplice, was responsible for the old Jewish 

 law against the eating of pork. It was, however, many thousands 

 of years later, in A.D. 1828, that the worms were first dis- 

 covered. A little over 50 years later, 1880-1891, the trichina 

 worm was the cause of international complications between the 

 United States and Germany, and during this time American pork 

 was excluded from German markets on account of the alleged 

 frequency with which it was found to be infected. The outcome 

 of this trouble was the beginning of the present American system 

 of government meat inspection. 



Prevalence. — Since the danger of infection from eating im- 

 perfectly cooked pork has been given wide publicity, and has 

 come about as near to being a matter of common knowledge as 

 any fact of parasitology, the prevalence of the infection has been 

 greatly reduced, but even now trichina embryos are found in 

 from 0.5 per cent to 2 per cent of the inhabitants of most civilized 

 countries, as shown by post mortem examinations. According 

 to Dr. Ransom, of the U. S. Bureau of Animal Industry, statistics 

 based on microscopic inspection of 8,000,000 hogs in the United 

 States show only 1.41 per cent infection with live trichina worms, 

 and a total of 2.57 per cent infection with live trichinae and 

 trichina-like bodies. 



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