How Houseflies Can Bring Dangerous Bacteria Into Your Home
One of the most common insects on the planet is the housefly (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 let's have a look at how the housefly spreads germs.
The Characteristics and Life of the Housefly
- The common housefly is around 6–8 mm in length, while the lesser housefly tends to be around 6 mm (Bay Environmental Science UK & Ireland).
- They have large, compound eyes: each section is called ommatidia. The lenses of the ommatidia are a thin, elongated shape and found on the outside of the eye. The thousands of ommatidia make a broad field of vision for the fly, with each individual lens acting as a separate eye. Vision is created almost like a mosaic that converges into one image. Unlike humans, however, a fly's eyes are immobile.
- A fly cannot bite. Instead its 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 its 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 three to four 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.
- The 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 lifespan 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.
How Houseflies Infect Our Homes
Houseflies are no doubt one of the biggest pests of the summer and carry among the most germs. Part of the problem is the way they live.
Flies walk among rotten food and other rubbish, feces, and decaying animals. They then fly straight into your home and onto your food. We've already mentioned how they liquefy food and then eat it. The main way that they contaminate our food, however, is when they rub their legs together.
Despite our feelings that the housefly 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.
What Kinds of Bacteria Can a Housefly Carry?
There are many kinds of bacteria that a housefly can carry—some studies show up to 200 different kinds—but a few of the most common are:
- Shigellosis: Bacillary dysentery and other diseases causing diarrhea.
- 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): Can lead to diarrhea, abdominal cramping, nausea, and vomiting.
- Poliomyelitis: Houseflies 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.
Keep in mind that these are just a few of the many bacteria and viruses that houseflies can potentially transmit. Although this looks like an alarming list of bugs and diseases, flies don't always carry these pathogens along with them though. 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.
More Interesting Facts About Flies
- 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 feces into soil. They also help to pollinate some plants.
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.
© 2013 Helen Murphy Howell