540 Yellow Fever 



vcloped, seems to remain throughout the subsequent life 

 of the insect. So far as it was possible to determine, only 

 one species of mosquito, Stegomyia fasciata, served as a host 

 for the parasite whose cycles of development in the mosquito 

 and in man must explain the symptomatology of yellow 

 fever. 



In order to establish these observations, experimental 

 inoculations were made upon human beings in sufficient 

 number to prove their accuracy. Unfortunately, Dr. 

 Lazear, one of the victims of the experiment, lost his life 

 from an attack of yellow fever induced by mosquito bites. 



Major W. C. Gorgas * based the quarantine of yellow fever 

 for the city of Havana upon the mosquito theory, and has 

 had the extraordinary success of actually stamping out the 

 disease. The quarantine and prophylaxis are very simple. 

 The breeding-places of the stegomyia are drained and closed, 

 and oil is poured upon unavoidable pools to prevent the 

 embryo mosquitos from breathing. Yellow fever patients 

 are protected from mosquitos, that might become infected, 

 by nets, and non-immune persons are to sleep under mosquito 

 canopies in rooms with screened windows. 



Reed, Carroll, and Agramontef came to the following 

 conclusions : 



1. The mosquito C. fasciatus serves as the intermediate 

 host of yellow fever parasite. 



2. Yellow fever is transmitted to the non-immune indi- 

 vidual by means of the bite of the mosquito that has pre- 

 viously fed on the blood of those sick with the disease. 



3. An interval of about twelve days or more after con- 

 tamination appears to be necessary before the mosquito is 

 capable of conveying the infection. 



4. The bite of the mosquito at an earlier period after 

 contamination does not appear to confer any immunity 

 against a subsequent attack. 



5. Yellow fever can be experimentally produced by the 

 subcutaneous injection of blood taken from the general 

 circulation during the first and second days of the disease. 



6. An attack of yellow fever produced by the bite of a 

 mosquito confers immunity against the subsequent injection 



* International Sanitary Congress held at Havana, Cuba, Feb. 16 

 1902 ; Sanitary Department, Havana, series 4. 



t Pan-American Medical Congress, Havana, Cuba, Feb. 4-7, 1901; 

 Sanitary Department, Cuba, series 3, 1902. 



