PREVALENCE 287 



In some European countries the infection is somewhat ' less. 

 Some of the great epidemics of trichiniasis (or trichinosis) in 

 Europe have been attributed to American pork, but according 

 to Ransom there have been no authentic cases of the disease in 

 Europe from American pork up to recently, and, so far as known, 

 none recently. Our slaughterhouses have been referred to as the 

 great breeding centers of trichina, but this is true only as to 

 slaughterhouses not under federal inspection. 



The role of the rat in the spread of trichiniasis can readily be 

 appreciated when the statistics concerning the infection of these 

 animals in slaughterhouses, stables, etc., are examined. Of 51 

 rats captured in the Boston abattoir some years ago 39 (77 

 per cent) were infected, and every one of 40 captured in a large 

 exportation slaughterhouse in the same city was infected. Rats 

 captured in stables where no hogs are kept, however, are usually 

 less trichinized. Rats in localities where an epidemic of tri- 

 chiniasis has recently swept through are usually extensively 

 infected. 



The prevalence of the disease in man is by no means parallel 

 with its prevalence in other animals. The great controlling 

 factor is the method of eating pork. Among such people as 

 Americans, English and French, where pork is almost always 

 eaten cooked, trichiniasis is rare and comes only from eating 

 pork not thoroughly cooked, thus allowing a few worms to escape, 

 though ordinarily not enough to cause serious disease. On the 

 other hand very fatal epidemics have occurred among the Ger- 

 mans, Austrians and Italians, who are very fond of raw pork, 

 especially in the form of sausage or " wurst." Nearly all the 

 epidemics in America have been among the Germans or Italians 

 who still cling to their native habits. 



According to statistics compiled by Dr. Ransom in the five- 

 year period from 1909 to 1914, 320 cases occurred in the United 

 States, with 6 per cent fatality. The majority of all cases are 

 reported as being caused by raw sausage or raw ham, and usually 

 home-made or prepared in meat shops on a small scale. As stated 

 by Ransom, " no cases of trichinosis have been reported which 

 trace back to sausage prepared in establishments conducted on 

 a large scale. While it is not impossible that such cases might 

 occur, the chances seem very remote, for the reason that in such 

 establishments any one lot of sausage is invariably made up of 



