DEFEATING THE MOSQUITO

Dominion, Volume 19, Issue 48, 20 November 1926, Page 24

DEFEATING THE MOSQUITO

AFRICAN METHODS

One of the most notable things about the mosquito is that it is the female of the clan that does the damage, She is the one with the long proboscis which is capable of puncturing tlie skin of the human and extracting his blood, or some of it. Apparently the gentleman mosquito is a gentleman—does not go round puncturing people’s skins and sipping their blood. In these circumstances 1 hope he leads an easy life with his wife, but it seems a little unlikely. • All female mosquitoes have the skinpuncturing, blood-drinking habit. Some of them, besides this, can introduce into the human system microscopic organisms which develop and multiply in the blood and give rise to malarial fever, or to yellow fevex k Only a Tew years ago it was believed, and taught, that malaria was caused by the exhalations from marshy pools. The light mist that often gathers at eventide about ponds and streams and marshes was held to be responsible for it. But now we know that it is transmitted by the mosquito, and by the mosquito only. If there were no mosquito there would be no malaria, no yellow fever. There was this amount of right in the old notion. The mosquito breeds in water, only in water. The lady mosquito lays her eggs in water; they hatch out there; and for the earliest days of its existence the mosquito is a 'sort of tadpole—you can see the tiny things swimming about. If there were no water there would be no mosquitoes. But we cannot abolish water just in order to do away with mosquitoes. Various suggestions have been made, in the Press and elsewhere, for dealing with the mosquito plague with which we are threatened. One is to introduce into water a chemical which kills the mosquito, by poisoning, in the earliest stage of life, whilst doing no damage to humans and cattle. Unfortunately the chemical proposed for use is by no means tasteless, and to those of 'us who remember the chlorinated water that in France used to come up to the Line, in petrol tins usually, this suggestion will not commend itself.

Another Authority advises the pouring of kerosene on to water, the kerosene forming an infinitely thin coat on the surface which, by preventing the voting mosquito from coming to the top to breathe, suffocates, and so disposes of it. One objection to this is that manv humans, and all cattle, dislike kerosene in their water, bath, or drinking.

The mosquito breeds in any water, anvwhere—still water or running water; and there is so much of both in this country. In practice the inoculating of it with anv chemical is impossible. Even if von could inoculate fill the water with the chemical, it would not stav there; vou’d have to be inoculating all dav and every day. And similarly with the kerosene: a heavy rain would necessitate the kerosene-spreading all over again.

In West Africa, which is a malaria country and a mosquito country hors

concours, I was during many years concerned with the war against both (writes John Leith in “Chambers’s Journal”). Experience showed that if you are dealing with a very small and thickly populated area, if you employ hosts of officials, if you are not limited in expenditure, and if you drag in the law to help, it is possible to destroy the mosquito in that area, and keep it free from them—just so long as you carry on with the expenditure, and the officials, and the police. I remember the Port Medical Officer at Lagos once telling me that he had twelve hundred summonses awaiting hearing. These were summonses against people in whose back yards officials had discovered empty tins, or fragments of pot, or bits of calabash, anything containing water in which mosquitoes might breed. Lagos is one town, which is also a capital and a seat of government, and it stands upon an island. It is, so far as I know, the only spot in all our vast West African territories from which we have succeeded in abolishing the mosquito. Mosquitoes are most active in the dark ; on dull days a few may be seen about, but they shun the bright sunshine. Also they dislike wind, preferring an atmosphere that is still, and hot, and dark. Further, a mosquito operating when the victim is asleep is more likely to achieve her stabbing—which is by no means an instantaneous process, but rather a prolonged one—than when the said victim is up and about and noticing. The stab that does the harm is the leisurely completed stab, not the aborted one. Mosquitoes dislike smoke If you are picnicking on a dull day, and the mosquito bothers, you can drive her away by means of a small fire on which grass or green leaves are thrown, whereby smoke is produced. A ‘smudge’ this is called. . / In a mosquito area never sit about in the open after dark. Get inside the r tnosquito-proof room, or tent. For years in Africa I had a contraption like a giant meat-safe alongside my quarters. Sav twelve feet square and seven or eight feet high—juts a frame of light match-boarding with wire gauze stretched all over. Nightly, when it got dark, I used to retire within it, and there read, dine and write, and spend the hours till bedtime, in comfort. Outside, the mosquitoes buzzed and bummed, registered disappointment, hunger and thirst, anger—and stayed outside. Lastly, if you are in a place where mosquitoes are frequent, it is sound and safe and simple to take five grains of quinine daily. It is made up in tabloids which are small, inexpensive, convenient for travelling There are various preparations, of which in Africa we preferred the bi-hydro chloride. Dissolve the tabloid in water, coffee, whiskv and soda; it is not soluble in tea. Take it at the same hour each dav—this is important—nt breakfast of lunch, or dinner. Taken midway through a meal quinine causes no digestive disturbance, nnd will save von from malaria. Prevention is better than cure.