There are a wide variety of flies, including blow flies, cluster flies and the common house fly. As a family of winged polluters, they’re too readily tolerated, without people understanding the potential effects.

Flies feed by vomiting saliva on food and then sucking it up. In doing this, they contaminate food, and the areas where they’ve landed, with bacteria from their gut and feet. Flies can be responsible for transmitting food poisoning, dysentery, typhoid or cholera. 

They may also carry the eggs of parasitic worms.