Cockroaches are similar to that of flies in how they transport and transmit disease to humans. Their preference is to live in warm, humid, temperature controlled conditions such as hospitals and kitchens. They have also been know, where they live near humans, to eat human faecal matter and infected material. They are extremely mobile animals and can easily crawl from sewers and drains through to broken taps and pipework. This illustrates their massive potential as spreaders of pathogens (disease) to humans. It has been proven that when controlled the risk of gastro-entric disease is greatly reduced or curtailed. It has also been indicated that cockroaches, and some other insects/mites, may be responsible for allergies in humans i.e. asthmatic problems and urticating rashes. If this is the case then removal of the creature just isn't enough, the whole infested area needs to be thoroughly cleaned and any dead insect also removed.