Flies thrive in moist places where there is garbage and feces. They are active in daylight or in artificial light and rest during darkness on walls, fences, wires or other objects.

"The housefly is attracted by the smell of fermenting or putrefying material. It feeds primarily on liquids, including moisture on decayed fruits and vegetables, fecal matter and water. It also seeks food on moist skin surfaces such as the mouth, eyes, sores and wounds. It dissolves dry substances with secretions from its salivary glands and by regurgitating part of the liquid present in its crop, thus producing what is known as a 'vomit spot,'" according to the editors of "Health Alert", a publication of the Health Action Information Network (HAIN).

Unlike other insects, flies don't bite but their bark is a lot worse for they can transmit many serious diseases. This usually occurs when they alight on animal and human feces and carry germs to food and water.

"The housefly can also transmit parasitic worms and cause skin infections. Furthermore, it leaves droppings on food and dishes, which may lead to contamination of food," said "Health Alert."

One of the diseases transmitted by flies is cholera, a severe and contagious condition that can cause death by dehydration. Cholera originated in India and is present in areas where sanitation is poor and improper hygiene is practiced.

The bacterium that causes cholera is found in human feces and is carried by flies to food or water. Once ingested, the bacterium takes up residence in the intestines, causing inflammation, diarrhea, vomiting and severe cramps in the arms, legs, and abdomen for the next three to 12 hours. Untreated, the victim collapses and may die in 24 hours.

Flies can also spread the bacterium that causes typhoid fever - another common illness. When contaminated food or water is ingested, the typhoid bacterium causes fever, headache, weakness or fatigue, and diarrhea in one to two weeks or sometimes after 60 days.

In a third of patients, complications like intestinal bleeding which is characterized by a sudden drop in blood pressure, shock, and bloody stools may appear. Other rare complications of typhoid fever include pneumonia, meningitis, and infection of the bladder, kidney or spine. (Next: Protect yourself from dirty flies.)

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