Flies are scavenging pests that feed on and lay their eggs on decaying debris. Diseases that flies regularly spread include Salmonella and E. Coli. Because flies only have one pair of wings, they tend to be weak fliers; they constantly take off and land on surfaces, adding to the speed at which they spread parasites, bacteria, and other pathogens. Filth flies, like house flies, pose serious health risks and have the potential to contaminate large amounts of food, making them pests that we need to safeguard our homes against and keep away from our families.