HEALTH NOTES.

Otago Daily Times, Issue 20282, 15 December 1927, Page 9

HEALTH NOTES.

THE FLY. METHODS OF CONTROL. CARRIER OF DISEASE. Contributed by the Department of Health. With the advent of summer must be considered that most common of all household pests, the house fly, its life cycle, habits, methods of control, and relationship to disease. This insect is undoubtedly the commonest and most widely-spread of all insects ; one that has accompanied man wherever lie lias travelled —from the polar regions to the tropics. The structure of the fly is familiar to all It has one pair of wings. The front lof the head is occupied almost entirely ;by a pair of large, compound eyes. Each lof these compound eyes is composed of about 4000 faceted individual eyes, and so i the insect is provided with a wide range jof vision. The head also carries the “ pro- | boscis,” or, as it is familiarly called, the [tongue. This proboscis represents _ the 1 very much modified mouth parts of jaws of other insects, and is wholly adapted |ti sucking. The common house fly cannot bite. Other varieties of flies, such as the stable fly, do and can bit, and their mouth parts are modified accordingly. When not feeding and in a state of rest, the prol boscis is carried bent up in the inside of the lower part of the head, but when j the fly alights on food the proboscis or 4 tongue ” is protruded. It has a thorax ov chest, abdomen, and three pairs of legs. The terminal segment of the legs are so constructed that the fly can crawl on very smooth surfaces and can progress without difficulty in an upside-down position along ceilings. I They are extremely prolific. The adult female lays eggs and will deposit about 100 to 120 at each laying, and will repeat the performance about four to six times in one season, so that one female fly may lay anything up to 680 or so eggs in one season. These eggs are usually deposited in positions that are favourable to i their development. The site most commonly chosen is in the horse manure, but the eggs may be deposited in any decaying matter. Thus, the eggs may be deposited on decaying vegetables, decaying fruit, meaL human and animal excreta ox all descriptions. The eggs are pearly-white in colour. In suitable conditions as to temperature and moisture these eggs may hatch out in from 8 to 24 hours into definite larval stage, hut in unfavourable surroundings the hatchings may require four days. FEEDING HABITS. The fly is a constant guest at our tables, sipping the milk, tasting the sugar, and next minute may bo tickling its palate with a tasty morsel from a nearby ashtin or stable. It may be feeding on the most indescribable filth, and next moment be buzzing round the kitchen. Flies are always most numerous where filth abounds, and the number of flies present i' j in some measure a criterion of the sanitary conditions. Good sanitation implies an absence of breeding-grounds and an absence of exposed food, and so implies a minimum of flies. FLIES AND DISEASE. Flies may spread disease in more than one way. The* germs of disease may adhere to the body or legs of the fly. and may be deposited on its next resting-place. Thus disease germs may bo carried direct. They may also absorb disease germs in their food, and these germs may live some considerable time in the alimentary tract of the fly. These germs may then be deposited on its next resting-place either by regurgitation or vomiting, or in its excreta. So it is not to be wondered at that flies are implicated in the spread of diseases like typhoid fever, epidemic diarrhoea, dysentery, etc. It is considered that flies may spread the infection in summer of epidemic diarrhoea, which is such a serious disease in children. CONTROL MEASURES. The first essential of control is to remove the possible breeding grounds, and to control adequately those that cannot be immediately removed. Accumulations of decaying vegetables, dirty paper, kitchen and table refuse should not be allowed to remain about the premises. All sanitary arrangements should he kept clean, and rhe household privy fitted with a tightlyfitting, flypronf lid. Horse and cow manure should be frequently swept up and deposited in a manure bin protected from flies by a suitable lid. Such manure should be removed at least once a week, and buried in the garden or field. Another method of preventing the breeding of flies in manure is of spraying with such n solution as coal tar, sheep dip, or with an emulsion of crude tar oil and soap. Stables and cowsheds should be kept clean, all manure being removed at least twice a day. In the home no food should be exposed to the attacks of flies, aud every endeavour should be made to kill them hy the use of flytraps, sticky papers, etc. A useful solution is to add an ounce of formalin to a pint of water and milk, and expose in dishes about the rooms. Remember.—Flies spread disease. By carrying into persistent practice that wallknown slogan, “ to swat the fly,” much can be done to reduce danger to health from this source. All foodstuffs in the home or exposed for sale should be protected from contamination by flies. Remember, that flics spend most of their lives in a very circumscribed area, s' - that if pestered with them it is probable that the breeding-ground is near at hand, and should be sought for and dealt with efficiently.