Carrier Species
The deer mouse: North America's primary hantavirus carrier
About 10 to 30% of deer mice in endemic areas carry Sin Nombre virus. They shed the virus in urine, droppings, and saliva for weeks to months. Understanding this animal is the first step to prevention.
How to identify a deer mouse
Deer mice look similar to common house mice but are distinguished by their bicolored tail (dark on top, white underneath) and white belly. House mice (Mus musculus) have uniformly colored tails and are generally gray throughout. House mice are not known to carry hantavirus.
Where deer mice live
- Rural areas: Forests, grasslands, agricultural land, and brushy areas across the western and central US and Canada.
- Seasonal invaders: They enter homes, cabins, sheds, garages, and barns in fall and winter seeking warmth and food. This is when most human exposures occur.
- High-risk structures: Rarely used cabins, storage sheds, barns, and outbuildings that sit closed for weeks or months are prime habitats. Opening these buildings without ventilation is a common exposure scenario.
- Elevation: HPS cases are most common at elevations between 5,000 and 8,000 feet in the Four Corners region (New Mexico, Colorado, Utah, Arizona).
All hantavirus carrier rodents in North America
Deer mouse (Peromyscus maniculatus)
Primary carrierVirus: Sin Nombre virus | Region: Western and central US, Canada
The primary carrier of hantavirus in North America. Responsible for the vast majority of HPS cases in the US. Found in rural areas, forests, grasslands, and agricultural buildings. Frequently enters homes, cabins, and outbuildings in fall and winter.
White-footed mouse (Peromyscus leucopus)
Virus: New York virus | Region: Eastern US
Carries the New York hantavirus, which causes a milder form of HPS. Common in forests and suburban areas throughout the eastern United States. Often confused with the deer mouse.
Cotton rat (Sigmodon hispidus)
Virus: Black Creek Canal virus | Region: Southeastern US
Found in overgrown fields, ditches, and areas with dense ground cover. Carries a hantavirus strain that rarely causes human disease.
Rice rat (Oryzomys palustris)
Virus: Bayou virus | Region: Southeastern US
A semi-aquatic rodent found in marshy areas of the Gulf Coast region. Carries the Bayou hantavirus, associated with a small number of HPS cases.
How to protect your home
- • Seal all holes larger than 6mm (1/4 inch) with steel wool, caulk, or metal flashing
- • Store food in thick plastic or glass containers with tight lids
- • Keep grass short within 30 feet (10 meters) of your home
- • Move woodpiles, brush, and junk away from the building
- • Set snap traps (not live traps) in and around the home if activity is detected
- • Do not use poison bait inside the home, as mice may die in walls and attract other pests
- • Ventilate any closed building for 30 minutes before entering