Rodents and their fleas are capable of transmitting a variety of human diseases including plague, hantavirus and salmonella. The District is primarily concerned with community-wide risk of rodent-borne disease like plague, hantavirus or large community-wide infestations.
The District can help to provide advice and guidance and in severe cases, do rodent inspections. We do not conduct rodent baiting or trapping.
For more guidance on rodent control, visit the UC Davis IPM website.
Rodents of Public Health Concern in Placer County
Ground Squirrels and Chipmunks
Tahoe Basin area residents who find dead ground squirrels or chipmunks on your property that do not have obvious signs of trauma, please call (916) 558-1784 to report it. The District partners with California Department of Public Health to monitor for plague.
Deer Mouse (Peromyscus maniculatus)
Sometimes this mouse is called the white-footed mouse. Deer mice are jumpers and runners that receive their name due to their agility. Deer mice prefer forests, grasslands and agricultural crops and they are not normally found within urban and residential areas unless fields, forests or other suitable habitats surround those areas.
Deer mice are vectors of the Sin Nombre virus which causes hantavirus pulmonary syndrome and other serious complications. Deer mice shed the virus in their urine, droppings and saliva. In areas, especially indoors, where these rodents are found, take special precautions to prevent hantavirus transmission like wearing protective goggles and a mask, spraying a disinfectant on areas with droppings, urine or nest materials and wet mopping to avoid sweeping or vacuuming.
Roof Rat (Rattus rattus)
Sometimes this rat is called the black rat. They are slightly smaller than Norway rats. Unlike Norway rats, their tails are longer than their heads and bodies combined. Roof rats are agile climbers and usually live and nest above-ground in shrubs, trees and dense vegetation such as ivy. In buildings, they are most often found in enclosed or elevated spaces such as attics, walls, false ceilings and cabinets. The roof rat has a more limited geographical range than the Norway rat, preferring ocean-influenced, warmer climates. In areas where the roof rat occurs, the Norway rat may also be present.
Norway Rat (Rattus norvegicus)
Sometimes this rat is called the brown or sewer rat. They are stocky burrowing rodents that are larger than roof rats. Their burrows are found along building foundations, beneath rubbish or woodpiles and in moist areas in and around gardens and fields. Nests can be lined with shredded paper, cloth or other fibrous material. When Norway rats invade buildings, they usually remain in the basement or ground floor. Norway rats live throughout the 48 contiguous United States. While generally found at lower elevations, this species can occur wherever people live.
House Mouse (Mus musculus)
House mice are small rodents with relatively large ears and small, black eyes. They weigh about half an ounce and usually are light brownish to gray. An adult is about five to seven inches long including the three to four-inch tail. House mice thrive under a variety of conditions. They are found in and around homes and commercial structures as well as in open fields and on agricultural land. House mice consume and contaminate food meant for humans, pets, livestock or other animals.
To learn more about rodent-transmitted diseases, you can visit the California Department of Public Health Vector-borne Disease section or CDC Rodent website.