First Sanitary Work 291 



fumigating all houses in a town or village, will not 

 necessarily kill all the mosquitoes present in and 

 about the houses, though probably the greater part 

 may be destroyed. It is surprising how soon they 

 wUl disappear, if all the water containers and 

 places in which they oviposit are removed. We 

 believe that the thorough and rapid destruction 

 or protection of all possible containers and breed- 

 ing places is the most effective method of yellow 

 fever control, and that where the health officer is 

 supported by the residents, Aedes calopus eradi- 

 cation is quite possible. The campaign at San- 

 tiago de las Vegas, Cuba, proved this beyond 

 doubt. 



It is not absolutely necessary to eradicate all 

 Aedes calopus in order to eradicate yellow fever. 

 It is only necessary to reduce the number of adults 

 sufficiently to prevent their presence in the vicin- 

 ity of the places visited by non-immunes. 



The matter can be stated thus: In order to 

 eradicate yellow fever from a given community it 

 is necessary to reduce the number of Aedes calopus 

 to such a minority that there is no opportunity for 

 their biting an infected case during the first three 

 days of the disease, and surviving twelve days 

 after. Of course, the nearer the reduction reaches 

 complete eradication the better, especially in re- 



