What is West Nile Virus?

The main mode of transmission for WNV is through mosquito bites. Mosquitoes become virus carriers after biting infected birds. Since mosquitoes can bite more than once, they can then transmit the virus by biting another animal or a person. In rare cases, WNV can be transmitted during an organ transplant or blood transfusion. The virus cannot be transmitted from person to person.

The virus has been in Canada since 2002.

What are the symptoms of West Nile Virus infection?

Most infected people don't even realize they are carrying the virus because they have no symptoms. The risks vary with age: complications are very unlikely among children, but more common for those over 50.

One infected person in 5 will present mild symptoms such as headaches and fever, sometimes accompanied by body aches, pimples or red spots on the skin. Some infected persons will develop a serious disease such as encephalitis or neurological problems that in some cases are permanent. West Nile Virus may be fatal, but only in very rare cases.

Meningitis: inflammation of the lining of the brain and spinal cord

Encephalitis: inflammation of the brain

Acute flaccid paralysis: polio-like syndrome that can result in the loss of function of one
or more limbs

What are the long-term effects of West Nile virus?
 

• Physical effects, such as long-term muscle weakness and paralysis, fatigue and headache
• Cognitive effects, such as confusion, depression, problems with concentration and memory loss
• Functional effects, such as difficulty with preparing meals, going out, shopping, etc.
   

Sources: Health Canada and Santé et service sociaux