Mosquitoes and West Nile Virus
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Preventing insect-borne disease by taking precautions

What is West Nile virus?

The West Nile virus, originally from the West Nile region of Africa, has been spreading across North America since 1999. BC has seen many cases of the disease in people who have travelled to other parts of North America. Since 2009, the Interior Health region has experienced low levels of the West Nile virus activity in the Okanagan Valley. As similar conditions exist in other parts of our region, it is possible the virus may become present in other locations. Interior Health continues to work with BC Centre for Disease Control to investigate and report confirmed human cases of West Nile virus.

Should I be concerned?

The virus can be transmitted to humans from the bite of an infected mosquito.  This may result in:

  • No symptoms in most people – about 80% of people who contract the West Nile Virus have no symptoms.
  • Symptoms of West Nile Fever in some people – about 20% of people develop a syndrome including headache, tiredness, rash, fever, sore joints & muscles and sometimes stomach upset.
  • Serious symptoms in a few people - about 1 in 150 people who are infected will get a serious illness that can include inflammation of the brain (encephalitis), inflammation of the lining of the brain and spinal cord (meningitis), or even paralysis.  Some people can be left with long lasting disability, and about 1 out of 1000 people who are infected will die.

While anyone can contract the West Nile virus, people over the age of 50 have a greater chance of getting sick and are more likely to develop serious symptoms when infected with West Nile virus. Those with a weakened immune system are also at greater risk. It takes anywhere from 3 – 14 days after the bite before symptoms begin.

What can I do?

Take steps both here at home and when travelling to avoid mosquito bites this summer.

  • Eliminate mosquito habitat (standing water) on your property. Clean out and empty eaves troughs, pool covers, old tires or any other materials that can collect water.  Empty and clean bird baths weekly, install aeration pumps on ornamental ponds and water gardens.  Fit rain barrels with tight lids or screens and empty saucers under flower pots.
  • Install good screens on doors and windows. Check to make sure screens fit into the frame and that there are no holes or tears.
  • Try to avoid outdoor activities around dusk and dawn when mosquitoes are most active. 
  • Wear long-sleeved shirts, long pants and a hat. Choose light-coloured clothing since dark colours attract mosquitoes.  
  • Use repellent containing DEET or other suitable alternatives. Follow label instructions for use. For more information on repellents:

Other resources

MoH     PCQO