672 TRANSMISSION OF YELLOW FEVER BY MOSQUITOES. 



3'ellow fever germ in the blood and in the l)odies of infected mosqui- 

 toes. What success may attend their efforts remains to be seen, but 

 at all events the fiuidamental facts have lieen demonstrated that this 

 germ is present in the blood, and that the disease is transmitted l)y a 

 certain species of mosquito — C. faxciatus. 



The proper measures of prophylaxis, in view of this demonstration, 

 are given in the following circular, which was submitted for my 

 approval by the chief surgeon. Department of Cuba, and has recently 

 been published by the commanding general of that department, who, 

 until quite recently, was a member of the Medical Corps of the Army. 



CiRCCLAK, \ IIead(}uarters Department of Cuba, 



No. 5. i Havana, April 21, 1901. 



Upon the recoimneiulatioii of tlu' AVxA surgeon of the dei)artnient, the followmg 

 instructions are pul)hshe(l ami will he strictly enforeed at all military posts in this 

 department: 



The recent exj)eriments made in Havana hy the Medical Dejiartmeiit of the Army 

 having pntved that yellow fever, like malarial fever, is conveyed chiefly, and ])roh- 

 ahly exclusively, hy the hite of infected mostjuitoes, important changes in the meas- 

 ures used for the prevention and treatment of this disease have hecome necessary. 



1. In order to prevent the hreedingof niostjuitoes and protect officers and men 

 against their bites, the provisions of (ieneral Orders, No. (i. Department of Cuba, 

 December 21, 19(X), shall he carefully carried out, especially during the summer and 

 fall. 



So far as yellow fever is concerned, infection of a rorim or huilding simply means 

 that it contains infected mos(|uitoes; that is, mos(piit(jes which have fed on yellow 

 fever patients. Disinfection, therefore, means the emi)loyment of measures aimed at 

 the destruction of these mo.«(|uitoes. The most effective of these measures is fumiga- 

 tion, either with sulphur, formaldehyde, or insect jiowder. The fumes of sulphur 

 are the quickest and most effective insecticide, but are otherwise objectionable. 

 Formaldehyde gas is quite effective if the infected rooms are kept closed and sealed 

 for two or three hours. The smoke of insect powder has also been proved very use- 

 ful; it readily stupefies mosquitoes, which drop to the floor andean then be easily 

 destroyed. 



The wasiiing of walls, floors, ceilings, and furniture with disinfectants is unnecessary. 



8. As it has V)een demonstrate*! that yellow fever can not be conveyed by fomites, 

 such as bedding, clothing, effects, and l)aggage, they need not be subjected to any 

 special disinfection. Care should l)e taken, however, not to remove them from the 

 infected rooms until after formaldehyde fumigation, so that they may not harbor 

 infected mosquitoes. 



Medical othcei's taking care of yellow-fever patients need not be isolated; they can 

 attend other patients and associate with nonimnmnes with perfect safety to the gar- 

 rison. Nurses and attendants taking care of yellow-fever patients shall remain iso- 

 lated, so as to avoid any possil)U' danger of their conveying mosquitoes from patients 

 to nonimmunes. 



4. The infection of mosquitoes is most likely to occur (hiring the first two or three 

 days of the disease. Ambulant case.s — that is, patients not ill enough to take to their 

 beds and remaining unsuspected and unprotected — are probably those most responsi- 

 ble for the spread of the disease. It is therefore essential that all fever cases should 

 be at once isolated and so protected that no mosquitoes can possibly get access to them 

 until the nature of the fever is positively determined. 



Each post shall have a "reception ward" for the admission of all fever cases and 

 an "isolation ward " for the treatment of cases w hich prove to be yellow fever. Each 



