Of all domestic insects, cockroaches are most likely to carry bacteria that cause human food poisoning. Bacteria such as Streptococcus, coliform, salmonella, staphylococcus and clostridium may travel from a cockroach in a kitchen to food and people. Some people have an allergy to cockroach oils and break out in hives when exposed directly or through contaminated food. In homes with heavy infestations, cockroaches actually may feed on sleeping people by nibbling at sores, eyelashes, eyebrows and finger - and toenails. This musty odor varies with each cockroach species.
Cockroaches plaster their fecal matter to wood or cardboard.
When the fecal matter does not stick, people often find their droppings. Cockroaches have evolved to have negative phototropism, meaning they seek darkness and avoid light. By being active in the dark, cockroaches have a greater chance of surviving human efforts and those of other predators. One female German cockroach can produce 200,000 roaches in one year. They are highly adaptable to all environments and quickly become immune to pesticides.