Hantavirus Pulmonary Syndrome (HPS) is a severe, sometimes fatal, respiratory illness transmitted by infected rodents. The virus is shed through rodent urine, droppings, and saliva. Humans become infected by inhaling aerosolized particles of these materials; person-to-person spread does not occur in the United States. A common concern is the potential for the virus to remain active on inanimate objects, or fomites, such as clothing or tools. Understanding the virus’s survival time outside its host is crucial for determining appropriate safety and cleanup measures.
Hantavirus Survival Time Outside a Host
Hantavirus is an enveloped virus, meaning it has a fragile outer fatty layer that makes it susceptible to environmental degradation. Due to this structure, the virus does not survive for extended periods outside its rodent host or its excreta. The length of time Hantavirus remains infectious is highly dependent on surrounding conditions, with viability generally measured in hours or a few days.
Laboratory studies suggest the virus remains viable for about two to three days on surfaces at normal room temperature. Low temperatures, such as freezing conditions, can increase survival time, sometimes prolonging viability for several days or even weeks. Conversely, exposure to sunlight and ultraviolet radiation rapidly inactivates the virus, often within hours.
Desiccation is harmful to the viral envelope, so the drying of contaminated material significantly impacts survival. Porous materials like fabric can offer some protection if they remain damp. However, the drying nature of fabric typically leads to a rapid loss of infectivity. Therefore, the virus’s survival on clothing is generally limited to a few days at most, particularly if items are exposed to warm, dry conditions or sunlight.
How Hantavirus Contamination Occurs
Contamination begins when the virus is shed in the urine, droppings, and saliva of infected rodents, such as the deer mouse in North America. These excreta are dispersed in areas where rodents nest, feed, or travel, including sheds, attics, and storage areas. The virus is not actively airborne until these dried materials are disturbed.
The primary mechanism of human exposure is aerosolization, where dried viral particles are stirred up and inhaled. This occurs when contaminated materials are swept, vacuumed, or disturbed during cleanup. Clothing becomes contaminated when aerosolized particles settle onto the fabric or through direct contact with contaminated surfaces like floors or tools.
The risk of contamination is highest during activities involving direct interaction with rodent-infested environments, such as construction work or cleaning out unused buildings. Once viral particles settle on clothing, they become a secondary source of exposure if disturbed later, such as when the items are shaken or handled without precautions.
Specific Decontamination and Laundry Protocols
Handling potentially contaminated clothing requires specific safety precautions to prevent the re-aerosolization of viral particles. Before touching items, individuals should wear protective gear, including gloves (rubber, latex, vinyl, or nitrile) and an N-95 respirator, especially in enclosed spaces. Shaking out or vacuuming contaminated clothing is prohibited, as this releases infectious particles into the air.
Decontaminating Non-Washable Items
Items too large or delicate for immediate washing should be left outdoors in direct sunlight for several hours, as UV radiation inactivates the virus. Non-washable items kept indoors must be isolated in a rodent-free area for approximately one week, allowing the virus to naturally lose infectivity. After isolation, the items can be wiped down with a cloth moistened with a disinfectant solution.
Laundry Procedures
The washing process is effective because the virus is susceptible to heat and common household cleaning agents. Contaminated clothing and bedding should be laundered in hot water with standard detergent. For maximum effectiveness, the water temperature should be 160°F or higher, and bleach addition is recommended if the fabric permits.
Items should be dried immediately using a high-heat setting in a machine dryer, which provides additional viral inactivation. If machine drying is not possible, hanging items in direct sunlight achieves a similar deactivating effect. Items heavily soiled with rodent excreta or those that cannot withstand the necessary treatments should be sealed in double plastic bags and disposed of according to local regulations.
After handling and cleaning, the gloves worn during the process must be disinfected with a commercial disinfectant or soap and water before removal. Hands should then be thoroughly washed with soap and warm water. This multi-step process ensures the virus is inactivated and the clothing is safely decontaminated.