PROPHYLAXIS 



1241 



Dock-labourers working on suspected or disinfected ships should live 

 in special gnat-proof buildings, and be under medical supervision. 



With regard to an infected area, it must be remembered that 

 Stegomyia calopus is essentially domestic in its habits, that it is 

 active from 2 p.m. till early morning, but that it is quiescent between 

 the hours of 9 a.m. and 2 p.m., when, therefore, visits can be made 

 to infected areas without risk. Further, the mosquito is known 

 to bite dead bodies and suck the blood, but this will seldom infect 

 it, as a patient generally lives longer than the three days during 

 which the disease can be communicated ta the mosquito. Lastly, 

 it can pass through a screen with fifteen meshes, but not through 

 one with twenty meshes to the inch. 



The mosquito does not die after laying its eggs, but lives until 

 it has laid seven batches — i.e., some thirty days. The eggs laid 

 twelve days after infection are capable of carrying the infection 

 into the second generation, which can spread the disease fourteen 

 days after becoming imagines. As the mosquito is believed to be 

 non-infective when it bites in the daytime, non-immunes may visit 

 an endemic area in the day with impunity, but must not stay late 

 in the afternoon. 



When a person is moved from an infected room, disinfection 

 should be begun at once. All cracks, openings, etc., should be 

 closed with paper, and fumigation carried out, preferably by means 

 of sulphur dioxide gas, or if there is an objection to this because 

 of the damage it causes, pyrethrum may be used, but must be 

 burned in the proportion of i pound to 1,000 cubic feet of air- 

 space if the mosquitoes are to be merely stupefied, and 2 pounds 

 if they are to be killed; or tobacco, i pound per 1,000 cubic feet, 

 may be used. 



In addition, if an epidemic is to be eradicated, cases must be at 

 once notified to the central authority, and patients must be strictly 

 treated in mosquito-proof rooms, and every person, immune or 

 non-immune, must use mosquito-curtains, while an anti-mosquito 

 scheme on the lines mentioned under Malaria must be undertaken. 

 Special care must, however, be taken to eradicate, after a careful 

 survey, all the breeding-places, not forgetting those in old tins, 

 cocoanut-shells, gutters, small pools, etc. In endemic areas, houses 

 and public buildings should be rendered gnat-proof. Lastly, when 

 an epidemic breaks out in any place, it may be taken for granted 

 that the importation took place at least two to three weeks prior 

 to the discovery, for this is the time required for the incubation of 

 the germ in the mosquito and in man; and it may also be assumed 

 that mild cases are probably being treated for influenza or malaria. 

 Therefore a house-to-house visitation is almost necessary, in order 

 to find out the extent of the outbreak. 



Given a free hand and plenty of money, there should be no 

 difficulty in dealing with a threatened epidemic, but the public 

 must be won over to assist, and offenders must be fined for trans- 

 gressions against sanitation, as is done by the Americans in Panama, 



