Rats are extremely destructive. Besides causing severe damage to your home's structure, rats can also eat their way through your home's wiring. This can cause a short, which could lead to a fire inside a wall. When they get in your personal items, they gnaw and chew constantly until they have destroyed everything in their path. But, the biggest concern with a rat infestation is the damage they can do to your health. Rats are carriers of a multitude of diseases from hantavirus to the bubonic plague. Any food items that rats get into have to be discarded because it's contaminated. In addition, the fleas and ticks that live on rats also carry disease that can be passed to humans and pets.