HEALTH NOTES

Sun (Auckland), Volume II, Issue 506, 8 November 1928, Page 13

HEALTH NOTES

THE FLY AS DISEASE CARRIER

I METHODS OF CONTROL (Contributed by the Department of; Health.) With the advent ot summer must be considered that most common ot all I household pests, the housefly, its life, cycle, habits, methods of control, aud relationship to disease. This insect is undoubtedly the commonest and most widely-spread of all insects; and when fly-control methods are not carried out there is a great upward rise in the j curve of its prevalence during warm! summer weather. The structure ot the fly is familiar to all. It has one pair ot wings. The front of the head is occupied almost entirely by a pair ot large, compound eyes. Each of these compound eyes is composed of about tour thousand faceted individual eyes, an dso the insect is provided with a wide range of vision. The head also carries the "proboscis,” or. as it is familiarly called, the tongue. This proboscis represents the very much modified mouth parts of jaws of other insects, and is wholly adapted to sucking. The common housefly cannot bite. Other varieties of flies, such as the stable fly. do and caii bite, and their mouth parts are modified accordingly. When not feeding and in a state of rest, the proboscis is carried bent up in the inside of the lower part of the head, but when the fly alights on food the proboscis or "tongue” is protruded. It has a thorax or 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. 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 tidies 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 their development. The site most commonly chosen is in horse manure, but the eggs may be deposited in any decaying matter. The eggs are pearly-white in colour. In suitable conditions as to temperature and moisture, these eggs may hatch out in from eight to 24 hours into definite larval stage, but iu unfavourable surroundings the hatchings may require four days. Habits The fly is a constant guest at our tables, sipping the milk, tasting the sugar, and next minute may be tickling its palate with a tasty morsel from a nearby ash-tin 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 pres, ent is 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. Spread 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 be carried direct. They may also absorb disease germs in their food, and these germs may live considerable time iu 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 Methods The first essential of control Is to remove the possible breeding grounds, and to control adequately those that cannot be immediately removed. Accumulation of decaying vegetables, dirty paper, kitchen and table refuse should not be allowed to remain about the premises. All sanitary arrangements should be kept clean, and the household privy fitted with a tightlyfitting flyproof 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 a 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, and every endeavour should be made to kill them by the use of fly-traps, 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 well-known slogan, “Swat that 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 from flies. Remember that flies spend most of their lives in a very circumscribed area, so 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.