There are more than 150 000 species of fly worldwide and more than 7700 species in Australia. Some species are considered as important pest flies not only because their flying habit, but also the threat that flies pose to public health. Flies can efficiently transmit diseases to humans. They have hairy bodies that can carry disease organisms, and sponging mouthparts that often involve vomiting in the eating process and not retrieing all of it. Diseases that be spread by flies include Salmonella food-poisoning, dysentery, typhoid fever, cholera, hepatitis, tuberculosis, poliomyelitis, various parasitic worms and many others.