10 



MOSQUITO ERADICATION 





YELLOW FEVER VERSUS MALARIA CONTROL 



While the same principles that apply to the prevention of 

 malaria apply to the prevention of yellow fever, prevention of the 

 latter is by far the easier. In the first place, the range of breeding 

 places of Aedes calopus is much more restricted than that of the 

 Anopheles. Again, the Anopheles mosquito flies much further 

 than does Aedes calopus. Finally, yellow fever patients remain 

 infective for only 3 days, while malaria patients carry the 

 parasites sometimes for years. 



It is due for the most part, probably, to the last factor men- 

 tioned that yellow fever has been so largely eradicated through- 

 out the United States today, despite the fact that Aedes calopus 

 is still one of the most widely distributed of the Southern mos- 

 quitoes. In other words, the chief reason why yellow fever is 

 not still as prevalent in the South today as malaria is because 

 there are no human carriers. When an infected person does enter 

 the territory of Aedes calopus it is necessary only to protect him 

 from the mosquito for 3 days, and nobody else will be infected. 

 With malaria, the case is far different ; in almost every community 

 there are human carriers, who — unless preventive work is under- 

 taken — are bound to be bitten some time during the summer by 

 Anopheles mosquitoes, and the Anopheles, of course, pass on the 

 infection to other persons. 



DENGUE 



This disease frequently resembles yellow fever in its epidemi- 

 ology and symptomatology, and, although few persons have ever 

 died of it, the victim often is left in a more or less disabled condi- 

 tion for months. 



