Flies are not only one of our most common pest but they are also one of the most annoying. They can spread germs over your food. Diseases they can cause are gastroenteritis, dysentery, typhoid, polio, salmonella, and tuberculosis. Please don’t be eating when I tell you this but not only do their hairy bodies carry disease organisms but their sponging mouthparts often involve vomiting when they eat – yuck! So hence the importance of maintaining and keeping them away from your home.