DESTROYING AND REPELLING MOSQUITOES 105 



the mosquitoes to become infected must bite a yellow=fever 

 patient during the first three days of his attack. these 

 first three days, therefore, are the most important time for 

 preventing the access of mosquitoes to a fever patient. 



it is often difficult to decide during the first three days 

 whether a patient has yellow fever i hence the necessity 

 in threatened communities of placing a mosquito bar immedi- 

 ately around every patient who has fever of any kind, and 

 for three days at least. 



Facts about Screening 



1. The netting used should have meshes fine enough to prevent the 

 passage of mosquitoes (at least 18-20 meshes to the inch). 



2. It is important to screen the windows and doors of the house. 

 It is doubly important to screen the beds of fever patients. 



3. Mosquitoes can bite through mosquito nets when any part of 

 the patient's body is in contact with the netting. 



4. Frequent examinations should be made to see that there are 

 no torn places in the netting or that no mosquitoes have found a 

 lodgment inside. 



5. The netting should be well tucked in to keep mosquitoes from 

 entering. 



6. If mosquitoes are found within the netting, they should be 

 killed inside and not merely driven or shaken out. 



7. All cases of fever should be promptly reported to the local 

 health officer. Awaiting his arrival they should be covered with a 

 mosquito bar. 



Facts bearing on Mosquito Destruction 



1. Often mosquitoes live in the vicinity in which they breed. 

 They do not fly a long distance. 



2. Mosquitoes breed only in water — usually in artificial collec- 

 tions of fresh water. 



3. The young mosquito, or wriggler, lives in water at least seven 

 to twelve days. 



4. Although the wrigglers live in water, they must come fre- 

 quently to the surface to breathe. 



