The Dangerous House Fly


The house fly and its dangers

We all look forward to the coming of beautiful summer. However, with the bright sunshine comes dangers as well. One of the most common insects on the planet is the house fly - musca domestica and it can carry over 100 pathogens dangerous to humans.

Our food is one of the main targets likely to become contaminated so lets now have a look at how the house fly spreads germs.

House flies can carry more than 100 different pathogens, potentially fatal to humans.
House flies can carry more than 100 different pathogens, potentially fatal to humans. | Source
the eye of a house fly under an electron microscope
the eye of a house fly under an electron microscope | Source

The life of the house fly

The house fly is around 7mm in length but sizes do vary. They have large eyes that are usually a red shade and a bristled body. A fly cannot bite. Instead it's mouth consists of a spongy pad shape. This is used for releasing saliva and digestive juices that turns its' food into liquid form. The spongy area of it's mouth then soaks up this liquid.

Depending on the size of the fly a female can lay up to 500 eggs over a period of 3 to 4 days. Within a few hours - normally between 8 and 20 hours - of the female laying her eggs the maggots emerge. They eat anything and prefer a warm moist environment. The maggots continue to develop and grow for the next 4 to 10 days and then move onto the next stage of their growth. This next development is the pupa stage. The maggot remains as a pupa, wrapped up in a skin, for up to 10 ten days before finally emerging as an adult fly. Their life span is around 15 to 30 days and the female can begin to reproduce by the second day of her life. The female fly is larger than the male.

They can travel up to six miles within a 24 hour period although most of them tend to stay around their breeding areas.

Now that we know how they live and breed, let's look at how they introduce germs into our homes.

Did you know?

  • Flies feel, taste and smell with the hairs that cover their body. In particular the hairs that are around its mouth and on its feet are both used for tasting food. So basically a fly can taste what it walks on. If they have found a potential food source, they put the food in their mouth to taste it again.
  • Flies also have sticky pads on the bottom of their feet that allows them to walk upside down on smooth surfaces like glass with ease.
  • Despite the fact that flies do carry numerous germs they are also essential for the whole ecosystem. They are important, along with some other insects, in converting waste products such as rotten vegetation and faeces into soil. They also help to pollinate some plants.

How house flies infect our homes

House flies are no doubt one of the biggest pests of the summer and carry the most germs. Part of the problem is the way they live.

Flies walk among rotten food and other rubbish, faeces, decaying animals and then fly straight into your home and onto your food. We've already mentioned how they liquefy food and then eat it. However, the main way that they contaminate our food is when they rub their legs together.

Despite our feelings that the house fly is a dirty animal, it actually spends a good part of its day cleaning itself. If its body, eyes and antennae become clogged with dirt, then the fly's ability to use these areas to find its way around is severely compromised. It uses its legs to clean dirt from every area of its body and then rubs its legs so that the dirt falls off. Unfortunately if the fly happens to be on your kitchen surface or food, then the dirt shaken off will land there.

So what kind of bacteria can a house fly potentially carry? There are many to chose from - some studies show up to 200 - but a few of the most common are:

  • Shigellosis - Bacillary dysentery and other diseases causing diarrhoea
  • Salmonellosis - food poisoning, typhoid, paratyphoid and enteritis. Although flies are capable of carrying these diseases, it is much less common that the shigellosis diseases.
  • Bacteria causing conjunctivitis - this mainly occurs in areas such as Asia and Africa and the Pacific regions
  • E.coli (Escherichia coli)
  • Poliomyelitis - house flies do have the ability to transmit this virus - and other similar viruses - but normally only people who are perhaps already ill would be the most vulnerable.
  • Parasitic worms - especially tapeworms.

These are just a few of the many bacteria and viruses that house flies can potentially transmit. However, although this looks like an alarming list of bugs and diseases, flies don't always carry these pathogens along with them. In addition, most of us have good immune systems that block the majority of dangerous bacteria and viruses.

In most cases, simple precautions and hygiene in and around the home will keep people safe for the majority of the time.

Nature has her own forms of 'fly trap'. (Dionaea muscipula) Venus fly trap.
Nature has her own forms of 'fly trap'. (Dionaea muscipula) Venus fly trap. | Source
Some people go to the extremes to keep flies away.
Some people go to the extremes to keep flies away. | Source

House Fly Survey

Do you get concerned about house flies around your home?

  • Yes and I take every precaution I can to keep them out
  • Moderately and I take some precautions against flies but I don't worry too much
  • I don't worry at all about house flies and use basic precautions
See results without voting
Despite carrying numerous germs, flies are also beneficial to the environment. They can help to pollinate some plants.
Despite carrying numerous germs, flies are also beneficial to the environment. They can help to pollinate some plants. | Source

Keeping your house safe

For the most part I've looked at natural remedies to deal with house flies rather than using toxic sprays - they usually smell revolting and many that I've tried come shooting out in blobs that go over the windows and kitchen surfaces. Needless to say, don't spray fly repellent where food is lying and watch pets, it can be quite irritating to them. However, if you have a big fly problem use it until you can get other measures in place.

Basic Hygiene Ideas

Basic house hygiene is the first step when dealing with house flies. The main points to remember are:

  • Don't leave dirty plates with leftovers lying around, they're like beacons to house flies.
  • Wipe off crumbs and spills from kitchen surfaces as soon as possible.
  • Change washing cloths regularly - tiny particles of food left on a cloth will be an attraction to flies.
  • Empty waste bins frequently and don't leave them overflowing, this is a huge attraction to flies.

In addition, there are a number of natural remedies that helps to keep the number of house flies down. Using natural oils such as:

  • Lemon
  • Orange
  • Clove
  • Basil

Flies are not keen at all on any of these oils and its probably the scent that puts them off. Many people use some of these oils diluted in water and wipe down their kitchen surfaces. You can also try burning a little oil. You get a lovely smell in your kitchen and it keeps flies away. Alternatively pour some of the oil onto a cloth and leave the it sitting. You will need to use fresh oil frequently however, as the smell gets weaker when exposed to fresh air.

Keep food covered and ensure to wash any fruit or vegetables that have been sitting out for a time. Using clean kitchen towels or netting to cover food if you have to leave it out for any length of time prevents flies from getting to the food.

In addition, ensure that you don't inadvertently attract flies by leaving outside garbage buckets open or the lids not put on properly - garbage is one of the biggest lures to a fly. Ensure that your garbage is uplifted regularly.

If you have pets ensure that you lift their waste up if they are taught to use your garden. As mentioned previously, flies are very attracted to any kind of faeces.


Having plants just outside your door or windows are great for stopping flies entering.

  • Basil is a favourite with many people and they have pots of this herb just outside their door where flies tend to enter the most. There are many varieties of basil but any kind can be used to repel insects. People also take a leaf and rub it over their skin to prevent being bitten by insects.
  • Lavender is another excellent fly and other insects repellent. You can have pots of lavender outside or have it hanging inside in areas where flies love to visit.
  • Tansy is a beautiful little plant that not only repels flies but many other kinds of insects such as fleas, ants and moths. It's also believed to be a deterrent against mice.

You don't have to use these herbs as pot plants, many people make salves and also repellents out of the herbs to use as home made anti-fly spray.

Insect netting and screens

These come in various sizes and range from very cheap to expensive. If you want a permanent insect screen for doors and windows then it's best to buy as good a quality as you can afford. Personally and because living in Scotland, flies are only a nuisance for a few months at most, I use temporary insect netting for the windows. This only costs a few pounds/dollars and you put them up in a few minutes. When the fly season is over you take them down. Some brands you are able to wash and keep for the following year or you can just throw them in the rubbish.

At the other end of the scale you can have permanent insect screen blinds fitted. Most are of the roller blind type so you don't have to have it down all the time. Some types are also very pretty and have a lace effect so that it doesn't actually look like an insect screen at all.


I haven't personally used this method so I can't verify if it works. However, after talking to some folks on a few forums they swear by one particular method. Apparently filling a plastic bag with water and hanging it outside your doorway is an excellent fly repellent. There are a couple of theories why it might work. Firstly, the reflection created by the water could be confusing the fly and it moves off. Additionally the reflection might look similar to a spiders web to the fly's eye and obviously the fly wants to avoid spiders at all costs.

Fly Papers

I have to admit that although these sticky papers do seem to work I really do dislike them. The sight of dead flies hanging about my home just puts me right off. However, if your not as fussy as me then fly papers do work and they are cheap. However they are only really useful when used indoors and don't work all that well around a barbecue area for example.

Fly Zappers

These are one of the most popular methods of getting rid of flies, especially in commercial areas. They also work well in the home. Basically the flies and other insects are attracted to the light - usually ultraviolet light is used but some models have neon or mercury lighting. When they enter the zapper they are killed immediately by a charge of electricity. These fly controls can be rigged up for using outside the home for example at barbecue areas.

However, you should be aware that these bug zappers don't work against mosquitoes. In addition, they are a controversial device mainly because it's not just flies that it kills - harmless insects are caught as well. The problem is that because these zappers can kill huge amounts of insects in one night there are concerns about the ecosystems being affected. Whether you like insects or not, they are essential to the health of the planet.

One last word about bug zappers. I once had the misfortune to see inside one of these zappers that was being cleaned in the place where I worked. To put it mildly it was revolting! The thought of having to clean out hundreds of dead insects put me off completely! I prefer to stick to my lavender plants and oil.


Unless you have spiders who give serious/venomous bites then let them stay around if you're not too scared of them and provided you don't have too many. They are very effective at keeping flies and other insects under control. Personally, I don't mind the spiders hanging around in the summer in the hallway or just outside the kitchen, but no way do I allow them to stay in my bedroom!

Other methods

To finish off the hub I'll just quickly mention some research that is currently underway to try remove the numbers of flies we have around. For example scientists at the Agricultural Research Services - (Centre for Medical, Agricultural and Veterinary Entomology) Florida - are looking at how adult flies could be injected with a virus that will stop them reproducing. The virus - SGHV or salivary gland hypertrophy virus - will stop female flies producing eggs and male flies from wanting to mate.

Sure, flies are a pest and they do have the potential to carry some dangerous germs. However, they also have a crucial part to play in the ecosystem - both in reducing waste matter and helping to turn it into soil. They are also essential prey for other animals such as spiders. What would be the result of a sudden loss of thousands of flies in the ecosystem due to some human induced virus? Surely, unless there is an unprecedented plague of flies, using the insect repellent methods we have are enough to keep them under control? Do we really need to go to the extreme of screwing around with nature and her carefully balanced ecosystems?

Let me know what you think and I'd also love to hear about your own remedies for keeping insects at bay around your home.

© 2013 Helen Murphy Howell

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Comments 17 comments

Frank Atanacio profile image

Frank Atanacio 3 years ago from Shelton

House flies are nasty.. I get a lot of spiders because of the flies .. because I live near the woods and the flies are attracted to the rotting wild-life.. I have taken measures to keep them outdoors.. but spiders do help.. thanks for reminding us of the nasty side of summer LOL

Seeker7 profile image

Seeker7 3 years ago from Fife, Scotland Author

LOL! Hi Frank, I know, not the most positive way to start the summer - not that Scotland has that great summers at the moment, but we might get a surprise this year! But yes, the spiders do help and I have netting and lots of lavender hanging around inside and out and it tends to keep the little -------- away for most of the time!

Om Paramapoonya profile image

Om Paramapoonya 3 years ago

Thanks for your helpful advice. I do have a fly issue every summer here. I like the idea of using natural oils. It can repel flies and make the house smell nice at the same time. I'll definitely give this trick a try.

ChitrangadaSharan profile image

ChitrangadaSharan 3 years ago from New Delhi, India

Very useful and informative hub!

I don't have much problem of flies within my home as such, but I do take care that they don't enter my home, simply by avoiding sweet food here and there and keeping general cleanliness. Even one fly is very irritating. Thanks for this helpful hub!

sparkster profile image

sparkster 3 years ago from United Kingdom

Oh how beautiful God's creatures are haha! Very informative hub... but yuck!

Gypsy Rose Lee profile image

Gypsy Rose Lee 3 years ago from Riga, Latvia

Thanks for this informative and useful hub. I sure hate flies. They are a pain. We keep up plenty of fly papers and have swatters about because where we live we have a very old house and no air conditioning. So summer means open doors and open windows. Passing this on.

Seeker7 profile image

Seeker7 3 years ago from Fife, Scotland Author

Hi Om Paramapoonya, many thanks for stopping by and glad that you will give the oils a try. I certainly find that lavender works well where I live but there are many to chose from - good luck!

Seeker7 profile image

Seeker7 3 years ago from Fife, Scotland Author

Hi ChitrangadaSharan, lovely to hear from you as always and I'm glad that flies are not a problem for you and I agree, even one fly is very irritating!

Seeker7 profile image

Seeker7 3 years ago from Fife, Scotland Author

Hi sparkster - lol! yes, yuck indeed! They are all part of nature to be sure but why do so many of them have suck crappy habits!!

Seeker7 profile image

Seeker7 3 years ago from Fife, Scotland Author

Hi Rasam, I know flies do have their place in nature, but like you I can't stand them. Especially when they target your food. Also when out with the dogs, I hate the way the can really harass them! I had a fly swatter once but I missed most of the time so gave it up!!

mikkar profile image

mikkar 3 years ago from Nairobi

Sometimes you wonder why God created some things, but when you understand how ecosystem work you apprecite them. A hungry cat also eats houseflies

Seeker7 profile image

Seeker7 3 years ago from Fife, Scotland Author

Hi mikkar - many thanks for stopping by and for leaving a very interesting comment. Yes, I think the powers that be always have a reason for creating everything even if we don't always understand it. Now, I didn't know about hungry cats eating house flies, my dogs certainly chase them! LOL!

Jo_Goldsmith11 profile image

Jo_Goldsmith11 3 years ago

This is a great article and advice. I don't like houseflies and our cats are not doing their jobs lately in trying to catch them. We will be installing a screen door soon. :) I can keep our front door opened and let the air in and keep the flies out! I didn't know about wiping down the counter tops with lemon. I use Mr. Clean lemon scented. Is this the same thing?

Voted this Up +++, shared & tweeted. thanks again. :)

Seeker7 profile image

Seeker7 3 years ago from Fife, Scotland Author

Hi Jo_Goldsmith 11,

Many thanks for stopping by and glad you enjoyed the hub.

I'm the same, I can't stand flies or wasps - bees I don't have a problem with. My dogs are going nuts at the moment trying to catch any flies that do come into the house, so I've got the insect netting up, especially for nighttime, there's nothing worse than trying to sleep with some daft moth or crane fly buzzing about your head!!

I'm not sure, but I would think that if it is 'lemon scented' then it would have some of the extract from a lemon distilled into it and I would imagine it would work just the same.

Many thanks for the vote and the tweet!!

WiccanSage profile image

WiccanSage 3 years ago

Ewww... I always hated flies in the house but now I'm going to be just grossed out. That is nasty!

Seeker7 profile image

Seeker7 3 years ago from Fife, Scotland Author

LOL! Yes they are nasty little blighters. I do love nature and of course animals, but have to admit to having a hard time with flies and slugs - Yuck!!

frogyfish profile image

frogyfish 15 months ago from Central United States of America

Interesting and informative hub on these beautifully ugly creatures. The macro video was vivid! However, I do think there are some flies that bite -must have a different specie? I did not know basil was a repellent, but do use other essential oils - especially the lavender and lemon. We did use your electric zapper for a short while - and yes, got every kind of bug except the mosquitoes we were after. I don't probably agree that the fly-virus is a good idea either - we definitely need all the pollinators we have, as so many bees are being killed with chemicals. Your informative hub was a great read, so thank you!

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