I don't encourage them to stay around here because of this:
Opossums become a nuisance when they move into urban areas. When they live in or near inhabited buildings, the animal's smelly nesting habits and discharge of picky fluids cause offensive odors. Opossums can damage buildings by pushing in screened vents or window screens, scattering insulation, and chewing electrical wiring. They frequently get into garbage and may injure pets or expose them to disease in disputes over pet food. Opossums prey on wild birds and are capable of eliminating local populations of some species.
Opossums are carriers of many diseases: tuberculosis, relapsing fever, herpes virus, tularemia, salmonella, spotted fever, toxoplasmosis, coccidiosis, trichomoniasis, Chagas Disease, yellow fever, and rabies (rarely). They are important reservoirs for leptospirosis (hemorrhagic jaundice) in wildlife and humans. Leptospirosis is transmitted through the urine and feces of infected animals. Humans frequently pick up the disease by eating unwashed produce or windfall fruit, or by putting unwashed hands to their mouth (gum, cigarettes, etc.). Opossums are also heavily infested with fleas, ticks, mites and lice which are known carriers and transmitters of disease.
From this site: http://www.co.el-dorado.ca.us/ag/wildlife/possum.html
Opossums are carriers of many diseases: tuberculosis, relapsing fever, herpes virus, tularemia, salmonella, spotted fever, toxoplasmosis, coccidiosis, trichomoniasis, Chagas Disease, yellow fever, and rabies (rarely). They are important reservoirs for leptospirosis (hemorrhagic jaundice) in wildlife and humans. Leptospirosis is transmitted through the urine and feces of infected animals. Humans frequently pick up the disease by eating unwashed produce or windfall fruit, or by putting unwashed hands to their mouth (gum, cigarettes, etc.). Opossums are also heavily infested with fleas, ticks, mites and lice which are known carriers and transmitters of disease.
From this site: http://www.co.el-dorado.ca.us/ag/wildlife/possum.html