West Nile virus is a viral infection transmitted by infected mosquitoes. Mosquitoes get the virus by feeding on infected birds and then can transmit the virus to humans and animals.
The virus is usually spread by the bite of mosquito that has fed on an infected bird. Rarely, the virus can spread through blood transfusion, organ or tissue transplant, from pregnant women to unborn babies and through breastmilk.
Canadian blood services tests donated blood for the presence of West Nile virus.
Most people who are infected with WNV have no symptoms. Among those who develop symptoms, most have mild symptoms. These can begin 3 to 14 days after a bite from a mosquito that carries the virus.
Symptoms can include fever, headache, muscle aches, joint pain, swollen glands and rash. A few people will experience more severe forms of WNV; such as, encephalitis or meningitis (swelling of the brain or the lining of the brain). The symptoms of encephalitis/meningitis may include a rapid onset of severe headache, high fever, stiff neck and disorientation.
There is no specific treatment for WNV infection. Therefore, prevention is very important.
Anyone can get West Nile virus, but people with weakened immune systems and people with chronic diseases are at greater risk for serious health effects like meningitis and encephalitis. The risk of serious illness also increases with age.
In most parts of Canada, including Nova Scotia, the risk of being bitten by a mosquito that carries the virus is greatest from July until early September. The best way to prevent getting WNV infection is to avoid mosquito bites.
Preventing mosquito bites is the most important way of protecting yourself and your family from WNV infection.
Reduce the risk of a mosquito bite:
Eliminate potential mosquito breeding sites around your home:
Besides being uncomfortable, mosquito bites can lead to other problems.
There are other mosquito-borne infections in Canada other than West Nile virus. These include Western, Eastern and St. Louis Equine Encephalitis viruses. Symptoms are similar to those of West Nile virus and there are no specific medicines to treat most mosquito-borne diseases.
Prevention measures on how to protect yourself and your family from West Nile virus can also be used to protect yourself and your family from other illnesses passed to humans from mosquitoes. It is important to reduce the likelihood of being bitten, as well as, reducing breeding grounds around your home.
More information can be obtained at the Government of Canada’s web site.