Cockroaches might ride into a home in a grocery bag or even in clothing. In an attached home or apartment, pipes and holes in adjoining walls, floors and ceilings provide speedy walkways and portals for these stealthy, nocturnal travelers.
Cockroaches can swim into a home through sewer pipes.
One cockroach in a home needs to have mated only once to produce many egg capsules with 16-40 offspring in each. And, some cockroaches don't even need to mate to produce offspring. One cockroach can quickly turn into a full-blown infestation. Cockroaches can carry pathogens that cause asthma, allergies, abscesses, boils, bubonic plague, diarrhea, dysentery, gastroenteritis, intestinal infections, leprosy, lesions, typhoid fever, urinary tract infections and more. Of all domestic insects, cockroaches are most likely to carry bacteria that cause human food poisoning.