Hantavirus pulmonary syndrome, or HPS, is a severe illness that is caused by a virus. This rare disease was first described in the southwestern United States in 1993. Subsequent studies have shown that the virus has been present for a long time, but was simply not discovered until the early 1990s. 

The first time HPS was found in Canada was in 1994, when 3 cases were reported in British Columbia. Every year, 0-3 cases are reported among BC residents. Cases have also occurred in other western provinces.

HPS begins as a flu-like illness. In the early stage of the disease, a person may experience: 

• fatigue
• fever 
• muscle aches, especially in the thighs, hips, back, and sometimes shoulders

These symptoms are universal. There may also be:

• headaches
• dizziness
• chills
• abdominal problems, such as nausea, vomiting, diarrhea, and abdominal pain

Four to 10 days after the initial phase of illness, the late symptoms of HPS appear. These include coughing, chest tightness and shortness of breath. 

In Canada, the virus is found only in wild mice, specifically the deer mouse (Peromyscus maniculatus) which is widely distributed in North America. The mice shed the virus in their urine, droppings and saliva. The virus is mainly transmitted to people when they breathe in air contaminated with the virus. When fresh rodent urine, droppings or nesting materials are stirred up, tiny droplets containing the virus get into the air. This process is known as aerosolization.

Another way the disease is transmitted is when a mouse with the virus bites someone, but this type of transmission is rare.

Domestic pets are not believed to be a source of infection. 

In North America, there is no evidence that the disease spreads from one person to another.

HPS is extremely rare, however, it can be a severe disease. In North America, about 1 out of 3 people with HPS have died.

Diagnosis is made by taking a blood sample and testing it for hantavirus antibodies using the ELISA, Western blot or strip immunoblot methods.

If you have been exposed to mice or their droppings, and you have the symptoms described here, see a doctor.

Only the deer mouse is considered to be a significant source of hantavirus in BC. However, since it is not easy to determine what kind of rodents may be in a home, it is best to remove all rodents and rodent-proof your home. Here are some ways to determine if a home or workplace is infested: 

• Rodent droppings are one of the most reliable signs of a rodent problem. You may find droppings in cupboards, drawers or in bins, under the sink, along walls etc.
• Nests – you may find accumulations of materials that are soft and warm for rodents, like shredded paper, bits of insulation, furniture stuffing, etc.
• Food boxes, containers or food itself that appears to be nibbled.
• Since rodents need to gnaw things constantly, to keep their teeth from growing too long, you may find signs of gnawing.
• A musky odour may be a sign of an infestation.
• Seeing rodents in the daytime is a possible sign of a heavy infestation. Eliminate or minimize contact with rodents in your home, workplace or campsite:

You should get mice out of your home, take measures to keep them out, and learn how to safely clean up after them. Here are ways to eliminate or minimize contact with rodents in your home or workplace:

• Use spring loaded traps to remove rodents from buildings. Bury dead mice in a hole 0.5-1m deep, burn them or deposit them in sealed, double plastic garbage bags in the trash, as appropriate to local by-laws. Disinfect the traps after dead animals have been removed.
• Minimize the presence of mice by reducing the availability of food sources or nesting materials.
• Seal points of entry into buildings such as barns, sheds, or other outbuildings, warehouses, and summer cabins. 
• Use metal flashing around the base of homes to provide a strong metal barrier. Install so that the flashing reaches 12 inches above the ground and six inches down into the ground. 
• Cut grass, brush and dense shrubbery around homes and outbuildings. 
• Elevate sheds, woodpiles, garbage bins and outbuildings wherever possible. 
• Store hay on pallets. 
• Keep woodpiles and garbage bins at a distance of 30 m from the house.

Protect yourself while cleaning up droppings:

• Ventilate enclosed areas before cleaning for 30 minutes or more. 
• Wear an appropriate, well fitting filter mask, rubber gloves and goggles. Appropriate well-fitting masks include any one of several respiratory (breathing) protection devices. *NIOSH-approved 100 series filters - N100, P100, and R100 - (formerly called HEPA filters) or respirator with P100 cartridges is best. An N95 mask may also be used. These masks are available at most safety supply stores and some hardware and home building outlets. A dust mask for insulating or paint is not equivalent to these specialized masks. 
• Disturb the droppings and nesting materials as little as possible. Do not use a vacuum cleaner to remove them.
• Thoroughly and carefully wet contaminated areas with detergent or disinfectant to deactivate the virus. Wetting the area will prevent virus particles from being released into the air when material is disturbed during clean-up. Most general purpose disinfectants and household detergents are effective. Diluted bleach (one part bleach to 10 parts water) can also be used. Pour solution carefully onto debris to avoid aerosolizing any virus present – do not use a sprayer.
• Wipe up droppings, nesting materials and other debris with a paper towel and place in a sealed plastic garbage bag. Double bag the contents and place in the trash, as appropriate to local bylaws.
• Clean surfaces that were in contact with mice or their droppings with a solution of water, detergent and disinfectant.
• Wash rubber gloves with disinfectant or soap and water before removing them. Wash your hands with soap and water after removing gloves.
• You can get further information on how to take these special precautions, and about the safe and correct operation and use, and the limitations of these devices, from your local health unit or from WorkSafeBC.

If you are camping or hiking:

• Try not to disturb rodent burrows.
• Don’t use cabins where there are mouse droppings lying around until they are cleaned up.
• Keep your food in rodent-proof containers.
• Don’t sleep on the bare ground.