Hantavirus... Risks and Prevention

Hantavirus is a potentially fatal lung infection that is spread by deermice and other rodents. Protect yourself by being aware and taking proper precautions.

Hantavirus Pulmonary Syndrome (HPS), while extremely rare (only 400 cases have been reported in North America since its discovery in 1993), it is fatal in 50 to 60 percent of cases.

It is is spread through the saliva, urine, and droppings of infected rodents, particularly deermice, but other wild rodents can also carry the virus.

You can contract the disease through inhalation of respirable droplets of saliva or urine, or through the dust of feces from infected rodents. You can also get HPS if these contaminated elements enter your body through broken skin or are ingested in food or water. It is currently thought to be non-transferable through person-to-person contact, although a South American outbreak of a different strain from that found in North America is thought to be transferable this way.

What are the risks?

Rural living presents increased risks, particularly where outbuildings such as barns and sheds provide potential shelter for rodents.

The Canadian Centre for Occupational Health and Safety website lists the following occupations that present the greatest risk of exposure:

• Sweeping out a barn and other ranch buildings
• Trapping and studying mice
• Using compressed air and dry sweeping to clean up wood waste in a sawmill
• Handling grain contaminated with mouse droppings and urine
• Entering a barn infested with mice
• Planting or harvesting field crops
• Occupying previously vacant dwellings
• Disturbing rodent-infested areas while hiking or camping
• Living in dwellings with a sizable indoor rodent population

Cleanup

If you encounter rodent contaminated areas, the first task is to prevent further infestation by trapping rodents and sealing any points of entry. When no more rodents are being captured (usually about a week), wait a few more days before commencing cleanup.

Prior to cleanup, ventilate the area for at least 30 minutes by opening all doors and windows.

The need for proper protection during clean-up is critical. This includes use of high-efficiency particulate air (HEPA) filtered breathing apparatus. Ordinary dust masks WILL NOT filter the virus... they leave you exposed to infection. Wear rubber, latex, or vinyl gloves during cleanup.

Avoid dry cleanup techniques such as sweeping or vacuuming as these cause the infected material to become airborne.

The droppings, nests, and dead mice must be soaked for at least 5 minutes with at 1:10 solution of bleach or a commercial disinfectant (follow manufacturers instructions). A spray bottle can be used soak the area, paying particular attention to droppings and dead rodents. These materials should be picked up with a paper towel or rag and placed in a plastic bag and disposed of by burning or burial, or double bagged and disposed of in the trash.

Proper disposal or washing of protective gear and clothing is critical. Masks, gloves, and disposable coveralls should be burned or buried, or double bagged and disposed of in the trash. Some protective clothing such as overalls can be washed (separately from regular laundry) in a bleach solution, detergent, and hot water and dried in a hot dryer. Handle with gloves until washed.

After cleanup, disinfect any areas that might have been contaminated:

• Wash floors with disinfectant/bleach solution
• Steam clean furniture and carpets where there is evidence of exposure
• Any bedding and clothing with exposure to rodent urine or droppings should be washed with detergent in hot water.
• After removing protective gloves, thoroughly wash hands or use alcohol-based waterless hand cleaner if soap and water is not available

Further advice about cleanup can usually be obtained by contacting your local public health office.

Symptoms and treatment

If you suspect exposure, early treatment is important. Inform your doctor that you were exposed to rodent droppings and that you suspect Hantavirus.

The time between exposure and onset of the disease is two to three weeks. Early onset usually involves vague flu-like symptoms such as fever, cough, headache, muscle ache, nausea, and vomiting. The disease progresses rapidly and includes an abnormal drop in blood pressure, fluid in the lungs, difficulty breathing, and respiratory failure. Death can occer within days of the onset of early symptoms.

While there is no specific cure for the disease, many of the symptoms can be treated. Patients with HPS will likely be treated in the intensive care unit in a hospital. Anti-viral drugs may be administered.

Prevention

Obviously prevention is your best course of action. So, try to avoid contact with rodents and their droppings. Follow these guidelines to help ensure your property remains rodent-free.

• Eliminate potential nesting sites such as trash piles, abandoned equipment and machinery, and old tires.
• Seal all possible points of entry to your home and, if possible, to outbuildings (openings greater the 1/4").
• Keep wet garbage in rodent proof containers and dispose as quickly as possible.
• Trim grass, brush, and shrubs that are in close proximity to your home and other buildings (at least 100 feet/30 meters).
• Store firewood as far from your home as is reasonably possible.
• See our mouse control page for more tips on prevention.