Others, such as flies and cockroaches, walk on contaminated areas, particularly human excrement, and then walk on food, or on areas where food is being prepared. Diseases like cholera and typhoid fever can be spread in this way.

Certain insects are a bigger problem. In some places, such creatures as cockroaches and flies are not regarded as enemies, just as nuisances. But they truly are health hazards, and their movement in a home should be prevented as much as possible. Dirty kitchens, however, with cracks or holes where insects can hide, are like a playground for them. Garbage not properly covered is an open invitation to flies, cockroaches and vermin. Also, hogs raised near the house encourage flies to congregate. By all means, insects and rodents should be kept away from family members and from food.