They'll dig a hole in a new home as quickly as an old one. All a mouse needs is an opening large enough to stick a finger through. A raccoon or possum can squeeze through a hole the size of a softball. They can come through doggie doors, holes in walls, openings around pipes and dryer ducts venting to the outside. That's where roof rats get their name.
Rodents can be very destructive.
They chew through wallboard, gnaw on electrical wiring, and, if they get access to your food supply, can cause contamination. They also carry disease and fleas, and leave waste. According to the Centers for Disease Control and Prevention, hantavirus, a lung disease, is carried by rodents. Although the disease is rare, the CDC says hantavirus is contracted primarily by inhaling airborne particles from rodent droppings, urine or saliva left by infected rodents or through direct contact with infected rodents. There are many products on the market designed to rid your home of rodents, and most work effectively when used properly, experts say.