Mice, Rats and other rodents spread disease through bite wounds and by contaminating food and water with their waste products. Mice can also spread disease thanks to parasites, such as ticks, fleas and mites.

To keep mice and other rodents out of your home assure all holes of larger diameter than a pencil are sealed. Mice can squeeze through spaces as small as a dime
The sighting of even a single mouse or rat in your home can mean that there is an entire family (with aunts, uncles, and other kinfolk) living in your home's basement, the walls, or in and between stored items.

Then rodent control is a must.