YELLOW FEVER 171 



infection followed, showing conclusively that the 

 disease can be contracted only by the bite of the 

 mosquito, Stegomyia fasciata. 



In Havana, Cuba, during the year 1900-1901, the 

 yellow-fever cases numbered 1240 and the deaths 

 305. In the following year, 1901-1902, there were 

 31 cases and 6 deaths. 



Tjrphus fever, which resembles Rocky Mountain 

 spotted fever in some respects, is thought to be 

 identical with Mexican tabardillo ; it is also shown 

 that " Brill's disease " is a form of typhus infec- 

 tion. The specific germ has not been isolated. 

 The disease may be transmitted by the bite of the 

 louse, and possibly by the bite of the flea and the 

 bedbug. 



Rocky Mountain Spotted Fever. — This disease 

 as far as is known is confined to the Bitter Root 

 Valley of Montana and the neighboring mountains, 

 and is transmitted by ticks. The germ has not been 

 isolated. 



Epidemic Infantile Paralysis. — Although it has 

 been known for fifty years that this disease is 

 infectious and carried from one person to another 

 by contact, presumably in the nasal discharges, 

 the microorganism has not been isolated. 



