Background

The hantavirus can cause serious illness and death in humans. Cases of infection in deer mice have been confirmed in Algonquin Provincial Park by federal officials. Outbreaks of this disease in humans have been reported in the United States, British Columbia and Alberta.

One half of these cases resulted in death.

Until further surveys are conducted, the extent of the infection in Ontario and the risk to humans is difficult to assess. However, the seriousness of the disease warrants extreme caution.

What is the Hantavirus Infection?

The virus is carried by rodents and causes hantavirus pulmonary syndrome (HPS) in humans. HPS is characterized by flu-like symptoms, high fever followed by fluid in the lungs and a drop in blood pressure.

How does infection occur?

The deer mouse is suspected as the primary carrier, although other rodents and small mammals can be infected. Infected rodents shed the virus in saliva, urine and feces. Humans can be infected through:

• Inhaling particulate in air, if excreta becomes airborne;
• Direct contact with broken skin or mucus membrane;
• Ingesting contaminated food or water;
• Rodent bites.

Note: HPS is not contracted from other humans, dogs, cats or biting insects.

Who is at risk?

Infection risk is highest for people whose activities bring them into contact with rodents, rodent excreta and rodent habitations in rural areas. It is important to identify rodent infested areas, buildings and workplaces. Risk of exposure involves:

• Occupancy of previously vacant cabins or dwellings;
• Cleaning barns or outbuildings;
• Disturbing rodent infested areas;
• Inhabiting buildings with rodent infestations;
• Laboratory workers studying indigenous rodent populations;
• Maintenance workers, plumbers, telephone installers, electricians and construction workers who enter buildings, crawl spaces or sites that may be rodent infested.

How can risk of exposure be reduced?

It is important that people whose activities bring them into contact with any rodents take precautions.

General Precautions

• Eliminate rodent populations and reduce their access to dwellings;
• Restrict rodent shelter and food sources to within 30 metres;
• Eliminate rodent infestations;
• Clean up rodent contaminated areas.
• General Clean Up

Areas with evidence of rodent activity should be cleaned thoroughly while preventing dirt and dust from becoming airborne.

• Clean up personnel should wear rubber gloves;
• Spray dead rodents, nests, feces, traps & other items with disinfectant;
• Plastic bag and burn or bury all materials;
• Wash all surfaces and tools with disinfectant solution;
• Launder bedding and clothing in hot water and detergent;
• Before removing gloves, wash gloved hands with disinfectant solution, and thoroughly wash hands after removing gloves

Precautions for Confirmed Hantavirus by Rodent Infestation

• to work safely, clean-up personnel should be thoroughly trained in the measures of preventing exposure;
• wear disposable coveralls, shoe covers, rubber gloves and protective goggles;
• wear appropriate respiratory protection; such as half mask air purifying respirator with HEPA filter, or a powered air purifying respirator with HEPA filter;
• decontaminate all protective gear and dispose of disposable coveralls and shoe covers at the end of each session;
• all contaminated material should be burned or buried; or where not possible, it should be double bagged, labeled "infectious" and disposed of in accordance with local requirements

What about lab workers?

Risk includes inhalation of aerosolized excreta, ingestion, contact with mucus membranes or broken skin, and animal bites. Lab workers should refer to "Laboratory Biosafety Guidelines" for suitable handling procedures for infectious micro-organisms and O. Regulation 883 "Control of Biological or Chemical Agents."

Further Information

People in high risk settings need to be informed about symptoms and trained in exposure prevention.

If respiratory illness develops within 45 days of exposure, seek immediate medical attention and advise physician of potential exposure.

Physicians should consult the public health department if hantavirus illness is suspected.

These guidelines address situations for confirmed hantavirus affected areas. However, they are useful precautions against other rodent associated diseases, such as histoplasmosis and Lyme disease.