Rats and mice carry various infectious diseases, including Salmonella and Lymphocytic Choriomeningitis (LCMV) a serious disease for pregnant women; Mice leave little drops of urine wherever they go. Mouse urine can trigger asthma attacks in sensitive people. Rats may bite people when threatened. Babies are especially at risk since the rat may be in the crib with them, feeding on spilled milk.Both rats and mice instinctively gnaw on things. This is damaging to property and can be dangerous if gnawing results in wires spark.
The house mouse gnaws objects eats and contaminates stored food and transmits disease by droppings, urine, bites, and direct contact or contact with cats, fleas and mites. An opening larger than 1/4 in (6 mm) permits a house mouse to enter a structure.