There is no doubt that house flies are a huge nuisance to deal with; they are constantly flying around us, landing on our food, and are challenging to remove from our homes. While it is inevitable that a house fly or two will find a way into your house, when large populations are around, the spread of diseases by these pests is a concern.
House flies only have two wings and are weak fliers. Being a weak flier means they frequently land and take off from generally less than sanitary surfaces. After moving into your home, house flies contaminate surfaces and food with disease-causing pathogens and bacteria they have come into contact with during their travels.