Cockroaches are dangerous for a couple of reasons. First, their traveling and eating habits take them to many unsanitary places where they pick up bacteria, parasites, and other pathogens. If they then enter your home and walk around on your countertops, bathroom fixtures, and food, they will contaminate them with these germs, leaving you susceptible to serious illness. Cockroaches have been linked to the spread of thirty-three types of bacteria, six different parasitic worms, and at least seven other pathogens. Another reason to be concerned about a cockroach infestation is that they can trigger asthma symptoms, and even asthma attacks, in certain individuals.