Health Notes

Sun (Auckland), Volume I, Issue 245, 6 January 1928, Page 13

Health Notes

THE FLY

METHODS OF CONTROL CARRIER OF DISEASE (Contributed by tl%e Department of Health.) With the advent of summer must be considered that most common of all household pests, the housefly, 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 he has travelled —from the polar regions to the ti'opics. The structure of the fly is familiar to all. It has one pair of wings. The front of the head is occupied almost entirely by a pair of large, compound eyes. Each of these compound eyes is composed of about four thousand faceted indivdual eyes, and so 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 can 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. VERY PROLIFIC 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 eggs in one season. The site most commonly chosen is in horse manure, but the eggs may be deposited in any decaying matter. In suitable conditions as to temperature and moisture these eggs may hatch out in from eight to twenty-four hours into definite larval stage, but in unfavourable surroundings the hatchings may require four days. 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 kicthen. Flies are always most numerous where filth abounds, and the number of flies, present is in some measure a criterion of the sanitary conditions. Good sanitation implies 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 be 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.

The first essential of control is to remove the possible breeding grounds, and to control adequately those that eannot 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 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 coaltar,'" glieep-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, “to swat tne 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.