24 DDT — ^Killer of Killers 



By draining swamps and covering other bodies of water with 

 oil, this was accomplished, and the Panama Canal was built. 



Yellow fever is by no means as widespread as malaria, 

 and the yellow fever mosquito is much easier to control than 

 his malaria-carrying relative. The first frost kills Aedes 

 aegypti; therefore, the disease can only become established in 

 climates where it is warm all-year round. The breeding 

 habits of the insects also make control relatively easy. These 

 mosquitoes are very sociable: they like to live near man. In- 

 stead of preferring to breed in out-of-the-way swamps or 

 lakes, they breed in cisterns, water-barrels, flower vases, and 

 other small bodies of water around the house or barn. Thus, 

 just by seeing to it that there is no stagnant water — unless 

 it is covered with oil — around the premises, we can eliminate 

 this mosquito. 



When a study of the breeding habits of the yellow fever 

 mosquito showed that the insect could be readily controlled, 

 many people began to envisage a yellow fever-free world. 

 The success at Panama and the fact that yellow fever was 

 eliminated from Cuba within a year after the discovery that 

 the disease was transmitted by mosquitoes were certainly rea- 

 sons for supporting this belief. And when yellow fever 

 was eliminated from Rio de Janeiro and other places, every- 

 one was convinced that with proper efforts success could be 

 achieved within a very short time. 



But dreams of a yellow fever-free world proved to be 

 as futile as dreams of a world free from war. If every yellow 

 fever mosquito within miles of human habitation were killed, 

 if not a single himian being on earth had the disease, it would 

 still not be enough. The disease is not the exclusive prop- 

 erty of man — it is shared by monkeys and possibly other ani- 

 mals. The jungles of the world act as huge reservoirs of the 



