DISTRIBUTION OF YELLOW FEVER 



183 



there was no city on the whole Atlantic and Gulf coasts of the 

 United States which was exempt from yellow fever epidemics, and 

 the disease exerted a serious influence on the economic conditions, 

 especially of our Southern States. In New Orleans there have 



FIG. 57. Map showing geographic distribution of the yellow fever mosquito, 

 Aedes calopus (black lines), and former distribution of yellow fever (red stipple). 



been epidemics which have cost thousands of lives, the last one 

 occurring in 1905. In temperate cities the epidemics always 

 ended with the coming of frost and destruction of the transmitting 

 mosquitoes. Now the situation is quite different and there is 

 no reason to believe that the world will ever again see such a sight 

 as was formerly only too common a frantic, terrorized city 

 helpless in the grip of a deadly yellow fever epidemic. No 

 epidemic has occurred in the United States since 1905 and many 

 of the tropical cities, such as Havana, Manaos and Rio de Janiero, 

 which were formerly famous as endemic centers of the disease, 

 and from which it was carried to seaports in all parts of the world, 

 are now practically free from it. It is only in such notoriously 

 unsanitary cities as Guayaquil in Ecuador and Buenaventura in 

 Colombia that yellow fever still rages, with little or no attempt 

 on the part of the inhabitants to stamp it out. 



Nature of the Disease. Our present knowledge of the 

 nature of yellow fever and of its dissemination, which has made 

 possible the scientific checking of the disease and will undoubtedly 



