486 THE CONTROL OF MALARIA AND YELLOW FEVER 



Prevention. The control 

 of malaria depends upon the 

 destruction of malaria germs 

 in patients by the use of qui- 

 nine and the destruction of 

 the mosquitoes (Anopheles). 

 The frequent use of quinine 

 in malarial regions by those 

 not sick will kill the parasite 

 before it has a chance to 

 multiply. The rooms oc- 

 cupied by malarial patients 

 should be thoroughly 

 screened, so that the disease 

 may not be spread through 

 the infection of more mos- 

 quitoes. In fact, all dwell- 

 ings in any malarial district 

 should be well screened. Since the mosquitoes are in search 

 of food in the evening, it is unwise for people to go beyond 

 screen protection after dusk. Probably the best method of eradi- 

 cating malaria is to destroy the breeding places of the mosquitoes 

 by draining the swamps and filling in the low places. 



YELLOW FEVER 



Prevalence of yellow fever. Yellow fever is a much more severe 

 disease than malaria. The mortality in various epidemics has 

 ranged from 15 per cent to 85 per cent of the population. It is 

 also a disease which is more prevalent in tropical and subtropical 

 countries than in cooler climates. Formerly, epidemics occurred 

 in the Southern States, and the disease was very common in Cuba 

 and the Canal Zone. Much has been accomplished in the last 

 thirty years in eradicating this disease. In 1878, there were one 



Photomicrograph of malarial parasites in a red 

 blood corpuscle. 



