TYPHUS FEVER, TRENCH FEVER, ETC. 937 



in Dublin in the Nineteenth Century, and Strong 4 states that in 

 Dublin alone, in the epidemic of 1846, 60,000 people died of the 

 disease. In Mexico the disease has been endemic since the early 

 part of the Sixteenth Century, and here, as in South America, it 

 is known as Tabardillo. 



Hirsch states (we quote from Strong), that of 147 epidemics 

 which occurred in temperate and cold latitudes, 30 reached their 

 heights in the spring, 28 in the winter and spring, 21 in the spring 

 and summer, and 19 in the summer and autumn. As a matter of 

 fact, the disease is one of relatively cold climates and elevated 

 plateau countries. Nevertheless, it is also endemic in such places 

 as the North of Africa, where Nicolle 5 made his important dis- 

 coveries. In some large cities of countries that are not ordinarily 

 visited by typhus epidemics, the disease has remained endemically 

 prevalent among those parts of the population living under unclean 

 conditions. This is the case in New York where the disease has been 

 prevalent in a mild form for a great many years. 



Transmission is, as far as we know at the present time, entirely 

 by the agency of lice. The idea that lice were concerned in the 

 disease is not a new one. We find in Strong's study of the literature 

 that Murchison suggested it in 1876. Cortezo made a similar state- 

 ment in 1903, basing the opinion purely on clinical observation. 

 The matter was not settled until 1909 when Nicolle proved louse 

 transmission by infecting a chimpanzee with typhus blood and sub- 

 sequently showing that the disease could be transmitted to monkeys 

 by the bites of infected body lice, as well. This important result 

 was confirmed in 1911 by Ricketts and Wilder 6 in Mexico, and in 

 the same year by Anderson and Goldberger 7 of the United States 

 Public Health Service. Since that time many confirmatory observa- 

 tions have been made. 



Whether or not other methods of transmission are possible is 

 still somewhat in doubt. It is of course certain that direct trans- 

 mission of blood from an infected case can cause the disease, and 



4 Strong, Typhus Fever, etc., Kep. Red Cross, Serbian Epidemic, Harv. Univ. 

 Press, 1920. 



5 Nicolle, Compt. rend. Acad. d. Sc. 1909, 157, Ann. de I'lnst, Past., 1910, 

 1911, 1912. 



'Ricketts and Wilder, Jour. Infec. Dis., July, 1911, p. 9. 



7 Anderson and Goldberger, Pub. Health Rep., Washington, March, 1912 and 

 May 31, 1912. 



