A single housefly can carry more than 1 million bacteria on its body! But this isn’t really its fault. Nature dictates that in order for flies to procreate successfully, they must lay their eggs on some pretty germ-laden substances – including faeces and sometimes on the dead or rotting flesh of animals.
These substances provide the mature flies and their maggots with plenty of food. The trouble is that flies also like snacking on food we’re about to eat.
When houseflies land on your food, they literally vomit on it. They do this because their digestive juices help to break the food down into digestible parts, which are then sucked up. This process frequently results in germs from the flies’ other more distasteful food sources (at least as far as humans are concerned) ending up on your food. Flies also carry pathogens on their feet and their body hairs; actually, any fly body part is rather germy.
Among the diseases houseflies can transmit are dysentery, diarrhoea and typhoid.
Getting rid of flies
The first line of defence against flies (and several other unwelcome visitors to your home) is sound sanitation and good housekeeping:
Deny flies access to all food and food scraps. That means washing dishes and cleaning counter tops, stoves and floors as soon after preparing food as possible. It's the smell of food that attracts flies, so pack it away (in the fridge is best) rather than just covering it with nets and doilies - although these do help.
The smell of rotting organic rubbish of course also attracts flies. Empty kitchen bins at least twice a week – even more often if the rubbish includes rotting meat. It’s better to freeze discarded meat and then throw it out on garbage removal day. Keep outdoor bins as far away from your home as possible, in a cool place. All bins should have tight fitting lids, and it’s preferable to use a bin liner. Clean bins regularly.
Many kinds of flies and other pests like moisture and humidity, so reduce indoor (and nearby outdoor) sources of stagnant water e.g. don’t over-water indoor plants so that they stand in water. Check for mouldy areas.
Don’t forget the hard-to-reach places where food scraps may build up e.g. under the fridge. Sometimes organic matter also builds up in drains and may attract flies.
Keep pet bowls clean and don't leave food in them. Pets like hamsters should have their cages cleaned regularly.
Keep your garden and backyard as free of decaying organic matter as possible e.g. rake up dead leaves, fallen fruit etc. Pick up and dispose of pet droppings.
You can further discourage flies from entering your home by keeping doors and windows closed or screened, and sealing up cracks and holes – though you need to balance that with the even more important need to allow fresh air into the home.
Why not just spray the suckers?
Using pesticides should only be considered once you’ve done all of the above; getting rid of flies' breeding areas and food sources is much more effective than killing the adult insects (although this helps). Pesticide sprays are damaging to the environment and your health, and you preferably don’t want them used near you and your family.
Instead, try using traps containing glue or bait, or that employ a light source to attract insects. These are better than the other options, because they don’t involve spreading chemicals around your home. If you do opt for pesticides, keep their use to a minimum, and make sure you follow the instructions properly.
There are natural remedies too that many people swear by. I can’t say I’ve studied their effectiveness myself, but they’re worth a try: sachets of crushed mint, eucalyptus oil, bay leaves, citrus peal, clover or pine oil hung near doors and windows; basil e.g. in pots in your kitchen. At the very least, these should make your kitchen smell good.
And finally: invest in a good old-fashioned, non-toxic fly-swatter!
- (Olivia Rose-Innes, EnviroHealth Expert, Health24, August 2006)
*Centers for Disease Control and Prevention and U.S. Department of Housing and Urban Development. Healthy housing reference manual. Atlanta: US Department of Health and Human Services; 2006.