VICTORIA, BC - The presence of West Nile virus has been detected in British Columbia for the first time ever, the province announced today.

A mosquito pool sample collected from the south Okanagan tested positive for the virus at the Provincial Health Services Authority Laboratories at the BC Centre for Disease Control. At the same time, public health authorities are investigating possible West Nile virus cases in two Kelowna residents who had only travelled within the central and south Okanagan areas in the Interior Health region.

All previously recorded cases of West Nile virus in BC have been travel-related, acquired outside the province. Although the presence of West Nile virus is now confirmed in BC, people can take simple and sensible measures to protect themselves and their families from being infected.

“This doesn’t really come as a surprise,” said Dr. Perry Kendall, B.C. Provincial Health Officer. “We have been anticipating the arrival of West Nile virus in our province for several years now, especially considering that infection has been widely reported in humans and animals in several provinces across Canada and the United States in recent years, including provinces and states bordering BC. The important things to note are that B.C. has a robust mosquito and West Nile virus surveillance system, and that people can take common sense precautions to protect themselves from mosquito bites.”

Dr. Bonnie Henry, medical director of the vector-borne disease program at the British Columbia Centre for Disease Control, an agency of the PHSA, concurred. “Since West Nile virus first appeared in Canada, the public has consistently been advised to take sensible precautions to reduce exposure to mosquitoes, especially when outdoors. This includes wearing light-coloured long-sleeved shirts and long pants – especially in the evenings and early mornings when mosquitoes are most active – and using mosquito repellents that are federally registered, such as those that contain DEET and lemon eucalyptus oil.”

Mosquito larvae like to live in warm, nutrient-rich standing water; even as little as a teaspoon is enough. Surveying the outside of homes and buildings will help to reveal those areas that need to be monitored and from where standing water should be drained, especially from spring to fall. “Even though we are late in August,” said Dr. Paul Hasselback, medical health officer with the Interior Health Authority, “it would be prudent to ensure that homes, gardens, backyards and indeed any open spaces near residential and farm areas aren’t breeding grounds for mosquitoes. This and other basic personal protection steps are sensible precautions that all of us should take, and this is a public health message we have been reiterating year after year.”

Since 2002, BCCDC and regional health authorities have been working with local governments, the BC Animal Health Centre, wildlife officials, entomologists, and other agencies to look for West Nile virus in B.C. This includes an active monitoring and testing program for mosquitoes, humans, and dead corvids (including crows, ravens, magpies, nutcrackers, Steller’s jays and blue jays). 

“There is no fixed pattern to West Nile virus,” said Dr. Kendall.  “In some years, a number of provinces have recorded hundreds of cases. This year, however, there have been no reported cases in Canada. If confirmed, the two cases currently being investigated in B.C. will be the first.  But while the incidence of West Nile virus fluctuates, what should remain a constant are stringent surveillance and common sense personal protection. That’s our best strategy against West Nile virus infection.”

• The usual way for humans to get West Nile virus is through the bite of an infected mosquito.
• West Nile virus affects a range of animals, including horses.  Horse owners in BC are encouraged to talk to their veterinarians about the vaccine that is available to protect their animals.
• f people who are infected with West Nile virus, most will have no symptoms at all. About 20 per cent will develop an illness with fever, headaches and rash symptoms. In about 1 out of 150 cases, more severe neurological complications can occur such as encephalitis (inflammation of the brain) and meningitis (infection of the lining of the brain). 

Here are many simple things you can do to protect yourself from West Nile virus.

Unlike birds or other insects, most mosquitoes do not fly very far and tend to stay close to their breeding sites. You are most likely to be bitten by a mosquito from your own backyard.

• Clean up areas where mosquitoes like to breed. It doesn’t take much time (generally one week), or water for mosquitoes to develop from eggs into adults.
• Take a look around your home and get rid of mosquito-friendly places that would make good breeding sites or resting places for mosquitoes.
• Remove any type of standing water at least once a week.
• Clean up and empty containers that collect water such as old tires, flower pots, wheelbarrows, barrels, tin cans or even small containers like bottle tops that are outdoors.
• Drill holes in the bottom of used containers so water can’t collect.
• Change water in bird baths at least once a week.
• If you have a swimming pool, immediately remove water that collects on pool covers and make sure the pool’s pump is circulating.
• Turn over wading pools when not in use.
• Check leaves and drains: don’t let things pile up.
• Clear leaves and twigs from eaves troughs, storm and roof gutters throughout the summer.
• Check flat roofs frequently for standing water.
• Make sure drains and drainage ditches are not clogged.
• Stop mosquitoes from entering your home
• Check windows and door screens for holes and make sure they fit snugly into the frames, so mosquitoes cannot get in.

• If you can, avoid being out around dusk and dawn as mosquitoes that carry West Nile virus tend to be active at these times.
• Wear protective clothing, especially outside in the early evening and at dawn. This includes long-sleeve shirts or jackets and long pants that mosquitoes cannot bite through. Tuck your pants into socks for extra protection.
• Avoid dark coloured clothing as it can attract mosquitoes.
• Use mosquito netting for babies and toddlers in cribs and strollers.
• Use mosquito repellent. Putting on personal insect repellents that are federally registered, such as those that contain DEET, is an effective way to protect yourself from mosquito bites.
• There are also many repellents that have been shown NOT to protect against mosquito bites, including bug zappers, devices that give off sound waves and Citrosa plants.
• Tips when using insect repellent:
• Apply repellent sparingly on exposed skin or on top of clothing. Do not use under clothing.
• The repellent doesn’t have to be applied heavily to work – a light coating will do.
• Use your hands to rub the repellent over your skin after you spray it on. Research shows that mosquitoes will find and bite even very small sections of skin missed by the spray.
• Do not use repellent on open wounds, or if skin is irritated or sunburned.
• Do not get repellent in your eyes – if this happens, rinse with water right away.
• Avoid breathing mist from spray-type repellent. Always apply in a well-ventilated area; never apply spray repellent inside a tent.

Roy Wadia
British Columbia Centre for Disease Control
Phone: 604 707-2402
Email: roy.wadia@bccdc.ca

Jeff Rud
Ministry of Healthy Living and Sport
Phone: 250-208-4028
Email: jeff.rud@gov.bc.ca