366 TRICHINOSIS 



It will be noticed that in this case the parasite is able to 

 exist in various hosts, and that both sexual and asexual stages 

 are passed in the same host. The parasites are dispersed by 

 the flesh of an infested animal being eaten uncooked bj- an 

 uninfested one, either of the same or of a different species. 



§ 295. Manner of infection. The danger of human 

 infection depends entirely upon the mode of preparation of the 

 flesh. Thorough cooking, so that all parts of the meat reach 

 or closely approach the boiling point, destroys the parasites. 

 The frequency of the disease in different countries is referable, 

 therefore, largely to the habits of the people in the preparation 

 of pork. In North Germany where raw ham and wurst are 

 eaten freel)', the greatest number of cases have occurred. In 

 South German)', France and England cases are rare. In this 

 country the greatest number of persons attacked have been 

 those who eat raw or slightly cooked meat. Salting and 

 smoking of the flesh as practiced in this country' are believed 

 to be sufficient to destroy the parasite. There maj' be excep- 

 tional cases. Carl Fraenkel states that it is verj' doubtful if 

 any cases of trichinosis in Germany have been caused by 

 American pork. It is stated that Germany has yet to show a 

 single case of trichinosis due to pork of unc[uestioned Ameri- 

 can origin. 



Swine become largely infested according to Stiles from 

 eating rats. He made a careful investigation of this subject 

 and found that the rats about country slaughter houses were 

 infested to a large degree with trichinella. Hogs are fed in 

 large numbers on the offal and they also frequently devour 

 the rats. 



§ 296. Frequency. The dissecting room and post-mor- 

 tem statistics show that from one-half to two per cent of all 

 human bodies contain trichinella. The disease often occurs in 

 epidemics, a large number of persons being infested from a 

 single source. 



In swine the frequency of this parasite varies, but from 

 one to three per cent of the hogs whose muscles are examined 

 microscopically contain trichinella. 



Digitized by Microsoft® 



