Catch A Critter wants yo help you live a healthier life. Read what the Centers for Disease Control says about squirrels and opposums in the links following thier desciption.

Squirrels

Squirrels are commonly found in the urban setting that can become pests. Squirrels can tear up turf and flowerbeds, destroy bird feeders and consume pet food.During the winter, they will take advantage of spaces in homes and storage buildings that can provide them with shelter and warmth. Common damage caused by animals in attics and crawlspaces include torn insulation, chewed electric wires and odors from their excrement.

http://www.cdc.gov/mmwr/preview/mmwrhtml/00001177.htm

Opposums

While their natural habitats are diverse, ranging from arid to moist and wooded to open fields, opossum prefer environments near streams or wetlands. They take shelter in abandoned burrows of other animals, in tree cavities and brush piles, and beneath other dense cover. In urban and suburban settings they may den under steps, porches, decks, garden tool sheds, and if accessible, in attics, garages, and beneath houses, where they make an untidy nest of sticks and whatever else may be available.

http://www.cdc.gov/eid/content/14/4/676.htm