West Nile Virus

HealthLinkBC File Number: 
Last Updated: 
October 2015

What is West Nile Virus?

West Nile virus (WNV) is a disease usually spread between birds by mosquitoes. Mosquitoes can become carriers of the virus after biting birds infected with the virus. It is possible for people, horses and other animals to become infected if they are bitten by a mosquito carrying the virus.

What are the symptoms of West Nile Virus?

About 80 per cent of people infected with WNV will not get sick. About 20 per cent of people will have a mild to moderate illness that starts 3 to 14 days after being infected.

Symptoms may include fever, headache, body aches, fatigue, swollen lymph glands, and sometimes a rash on the body. These symptoms generally last about 1 week, but they can last much longer.

In less than 1 per cent of people, WNV infection can result in more serious illnesses such as meningitis (inflammation of the lining of the brain), encephalitis (inflammation of the brain), or polio-like paralysis. People who have one of these more serious illnesses may also have high fever, severe headache, confusion and weakness.

In very rare cases, WNV infection can result in death. If you develop a severe headache or neck stiffness for which you cannot find a cause, or other symptoms of WNV, contact your health care provider.

What is the treatment for West Nile Virus?

Many of the symptoms and complications of WNV can be treated, although there is no specific treatment, medication or cure for the infection. Most people who are infected with WNV get better, but it may take a long time to recover fully. There is no human vaccine for WNV at this time.

Where is West Nile Virus found?

WNV is found in many parts of Africa, Western Asia and the northern Mediterranean area.

The first outbreak of WNV in North America was in New York City in 1999. Since then it has spread to most states in the U.S. and across most provinces of Canada, including B.C.

What is the risk of West Nile Virus in B.C.?

There are many species of mosquitoes, but only a small number of these can carry and transmit the virus. Some of these are present in B.C.

Once the virus enters a community, the risk of infection continues to grow as it gets later in summer and especially if it remains quite hot. Overall, the risk of WNV in B.C. is considered low.

How can I protect myself?

Any activity that prevents mosquitoes from biting or breeding will help to reduce the risk of infection with WNV. There are many simple things that you can do to protect yourself:

  • Use mosquito repellent – Applying a mosquito repellent to areas of exposed skin is an excellent way to prevent mosquito bites. Check the product label for instructions on proper use. For more information about insect repellents, see HealthLinkBC File #96 Insect Repellents and DEET.
  • Wear protective clothing – Avoid dark clothing as it tends to attract mosquitoes. If you are in an area with lots of mosquitoes, wear loose fitting, full-length pants and a long–sleeved shirt to keep mosquitoes from biting. Mosquitoes that can carry WNV are most active in the evening and early morning, especially at dusk and dawn.
  • Install mosquito screens on windows – If you are in an area where there are many mosquitoes, spend more time in well-screened or enclosed, air-conditioned areas. Consider staying indoors when mosquitoes are most active, which is from dusk to dawn.
  • Prevent mosquito breeding around your home – Anything that can hold water is a likely mosquito breeding area. Identify and remove these areas on your property. A few things to do include: empty saucers under flowerpots; change water in bird baths 2 times a week; unclog rain gutters; drain tarps, tires and other debris where rainwater may collect; and install a fountain in ornamental ponds or stock them with fish.

Backyard pools can be a big source of mosquitoes and should be maintained regularly to prevent mosquito growth.

Could handling a dead bird infect me?

The risk of infection from handling birds is very low; however, you should not use your bare hands to handle wild birds or other animals (dead or alive). If you need to move a dead bird, the following precautions should be taken:

  • Do not touch dead or live birds with your bare hands.
  • Use a shovel to pick up the dead bird, place it in double garbage bags and be careful not to puncture the garbage bags.
  • If you do not have a shovel:
    • Use heavy-duty, leak-proof rubber gloves as used in house cleaning, or use several leakproof plastic bags as a glove.
    • Turn the plastic bags inside out over your hand, and grasp the bird, and then pull the bags out over the bird so the bird is inside the bags. Be careful not to touch the bird and keep your hands outside the bags. Handle the bird so its beak or claws do not puncture the gloves or bags.
  • Make sure you and your clothing do not contact the bird or its blood, body fluids or feces.
  • Dispose of the bird according to local bylaws.
  • Always wash your hands after disposal of any dead animal, even if you wear gloves.
  • If you would like to report an unusual cluster of dead birds, please call the BC Interagency Wild Bird Mortality Investigation at 1-866-431-BIRD (2473). Reports will be recorded, assessed to determine if further investigation is warranted, and if so, guidance will be provided on a case by case basis.

For More Information

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Is it an emergency?

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