• Until 1999, WNV was commonly found in Africa, Eastern Europe, West Asia and the northern Mediterranean area: there have been outbreaks of WNV in Egypt, Israel, India, France, Romania and the Czech Republic.
• In 1999, the first North American cases occurred in New York City. It is not known how the virus was introduced into the New York area. 
• Since then, it has established itself in nearly all of the United States (lower 48 States) and much of Canada (see the West Nile Virus in North America map). It has now been detected in B.C.

How serious is WNV?

• Most infected people will never know they’ve had the disease. Research indicates that only about one out of every five people who are bitten by a mosquito and infected with WNV will develop symptoms.
• Most people who do develop symptoms will experience varying degrees of an illness known as West Nile Non-neurological Syndrome. Even non-neurological forms of the disease may cause lasting health effects, including muscle weakness, memory problems and fatigue which may continue for months. 
• In less than one per cent of infected individuals (about one in 150), WNV can cause severe illness resulting in hospitalization. This includes swelling of the brain (encephalitis), inflammation of the lining of the brain (meningitis) or polio-like paralysis.
• The fatality rate is about 0.1 per cent.

• fever
• headache
• muscle weakness
• muscle and/or joint aches
• malaise
• rash
• sensitivity to light

• severe headache
• stiff neck
• meningitis
• encephalitis
• paralysis

Symptoms begin approximately three to 14 days after being bitten by an infected mosquito. Recovery from symptoms may occur in about a week with West Nile non-neuorolgoical syndrome and may take a year or more for West Nile neurological syndrome.

• People usually become infected with the virus through a mosquito bite.
• WNV is not spread through person-to-person contact such as touching, coughing, sneezing or drinking from a shared cup.
• Although the virus is not known to be transmitted to humans from animals, people should avoid handling dead animals or birds with their bare hands. 
• Less commonly, WNV can be transmitted through blood transfusion and organ transplants if the donor was recently infected with WNV.
• WNV can also be transmitted from a mother to her unborn child or through breast milk, but these events are rare. The benefits of breastfeeding outweigh the risk from WNV.

How likely am I to get sick with WNV from one mosquito bite?

• In areas where mosquitoes do carry the virus, usually only a small number of mosquitoes will be infected.  Most of the mosquitoes that bite humans are not able to carry WNV, but there is no easy way to tell the difference between ones that can and ones that can’t so it is important to prevent any mosquito bite.

Who is at risk for WNV?
Everyone who is outside during the summer months gardening, golfing, walking, camping etc. is at risk once the virus is in the area and should take precautions to avoid mosquito bites. While anyone can be infected with WNv, the chances of having a severe illness are greater as you get older, even if you are healthy. You may also be at greater risk if you have a weakened immune system.

• 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 from dusk to dawn as mosquitoes that carry WNV 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 (N,N-Dethyl-m-toluamide) 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.
• Do not use near food.
• Read the manufacturer’s instructions on the label carefully, including restrictions for use on young children and maximum number of applications per day.

• DEET is the short name for N,N-Dethyl-m-toluamide, a personal insect repellent that is approved for use in Canada.
• Insect repellents work by preventing insects such as mosquitoes from landing on and biting humans; they are not the same as insecticides which kill the insects.
• Never use a product labeled as an ‘insecticide’ on your body.
• The concentration of DEET should be no greater than 30% for adults and 10% for children; check the percent listed on the label to be sure.
• Studies have shown that products with lower concentrations of DEET are just as effective as the high concentration products, but they remain effective for shorter periods of time:
• Choose a product that meets your specific needs. For example if you plan to be outdoors for a short period of time, choose a product with a lower concentration of DEET and repeat only if you need a longer protection time. To see more information on the different types and the time to use the insect repellent, please click here
• More information on DEET and children
• Repellents containing DEET should not be used on children under 6 months of age.
• Use sparingly on children, avoid their face and hands.
• Use the least concentrated product (10% or less) on children 6 month to 2 years and apply only once a day.
• Don’t apply DEET more than three times a day to children 2-12 years of age.
• Always supervise children using insect repellents and avoid getting repellent on children’s hands to reduce the chance of getting the repellent in their eyes and mouths.
• Safety Tips on Using Personal Insect Repellents from Health Canada
• Statement on Personal Protective Measures to Prevent Arthropod Bites from Public Health Agency of Canada

• There are effective insect repellents registered in Canada that contain active ingredients other than DEET. These include repellents with p-Menthane-3,8-diol (PMD), also known as lemon-eucalyptus oil.
• This product has been shown to be as effective as DEET but the duration of protection is only about 3 hours for mosquitoes.
• Lemon eucalyptus oil should not be used on children less than three years old.
• Soybean oil products are also effective mosquito repellents but are not yet widely available in Canada.
• Products with the substance picaridin are also effective but are not yet available in Canada.
• Instructions for proper use are listed on each product label.

• Yes, there are no reported problems with pregnant or breast-feeding women using repellents with DEET.
• Use sparingly in the lowest concentration you need.