TRICHINELLA SPJRALIS 139 



infected by eating dead rats, but sometimes may be 

 infected by eating the refuse scraps from a slaughter- 

 house where pigs are killed. The infection in rats is 

 maintained by their eating each other. The diaphragm 

 in rats is the common site of infection. 



Prophylaxis. The association of rats and pigs is a 

 common one and is difficult to prevent, but every effort 

 should be made to destroy rats near pigsties. Pigs should 

 never be fed with the refuse from pork butchers' shops 

 or slaughter-houses. Thorough cooking of the meat kills 

 the embryos, but the temperature of all parts must be 

 raised to 62 to 70 C. This temperature is not neces- 

 sarily attained in cooking large joints. In certain 

 sausages uncooked pork is used. Inspection of pork is 

 not always practised, nor sufficiently thoroughly, especi- 

 ally in pork intended for export. " Trichinosed pork," 

 or " measly pork," is not allowed to be sold for human 

 consumption when the condition is detected. The parts 

 most commonly affected are the tongue, muscles of the 

 larynx, the diaphragm, and abdominal muscles. These 

 should always be inspected and if trichinae are found in 

 them the whole carcass should be condemned. In the 

 inspection small portions of the meat, preferably from 

 the tongue, larynx, and diaphragm, are squeezed between 

 two glass plates so as to be translucent. The encysted 

 larvae can then be readily seen with or without a hand- 

 glass. 



Trichinosis is very rare in England and France, more 

 common in Germany, and in some parts of America. 

 There is no information as to its frequency in most 

 tropical countries, but it occurs amongst the pigs in both 

 India and China. In Mahomedan countries pork is not 

 eaten by natives, and Europeans rarely eat pork in the 

 Tropics. There is at present little trade in frozen pork, 

 but what there is is mainly from China, and in some 

 parts of China a large proportion of the pigs are infected, 

 but it should be remembered that the trichina larvae are 

 not killed by freezing. 



