Mosquito Season and the
West Nile Virus.
Be aware. Be prepared.
What is West Nile Virus (WNV)?
How is the virus spread?
Who is at risk?
Symptoms of WNV
Is there a treatment?
What should I do if I think I have WNV?
What about pregnant women?
Is there a vaccine?
If I get WNV once, can I get it again?
What you can do
Cover up and avoid mosquitoes
Insect repellent tips
Products with DEET
Clean up around the house and yard
Dead bird disposal
Find out more
Other Links
What is West Nile Virus (WNV)?
West Nile Virus is a mosquito-borne virus that can cause disease in anyone.
The risk of becoming seriously ill is low in children but increases with age and
with levels of virus circulating in the mosquito population. Most people
who become infected experience no symptoms or have milder illness such as “West
Nile fever.” The virus can, however, result in serious neurological
illness such as encephalitis (infection of the brain) which can have long-term
complications and even cause death.
How is the virus spread?
West Nile Virus is transmitted to people through bites from infected mosquitoes.
There are many types of mosquitoes, most of which are simply nuisance mosquitoes.
The main carriers of WNV disease in Saskatchewan are Culex tarsalis
mosquitoes. Cases from blood transfusions, tissue transplants, and infection
from mother-to-baby in the womb, have been observed but are rare. The possibility
of transmission through breast milk, though very rare, is being investigated.
WNV is not spread by casual contact such as touching or kissing a person with
the virus. It is not spread by contaminated drinking water.
Screening programs are now in place in Canada to minimize risk of transmission
from blood products or transplants.
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Who is at risk?
People who are outside when there are mosquitoes, particularly people who are
active and outside during the summer months on the farm, at the cottage, camping,
hiking, gardening or golfing. The highest risk period in Saskatchewan is July
and August. Children are much less likely to get serious disease than are adults.
Risk of serious disease and death increases with age. Be sure to cover
up and use bug spray when outdoors to avoid contact with mosquitoes.
Symptoms of WNV
WNV affects the central nervous system. Symptoms vary.
- Serious symptoms in a few people. About one in 150 people
infected with WNV will develop serious illness. The severe symptoms can include
high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions,
muscle weakness, vision loss, numbness and paralysis. These symptoms may last
several weeks, and neurological effects may be permanent.
- Milder symptoms in some people. Up to 20 per cent of the
people who become infected will display symptoms which can include fever, headache,
and body aches, nausea, vomiting, and sometimes swollen lymph glands or a skin
rash on the chest, stomach and back. Symptoms can last for as short as a few days,
though even healthy people have been sick for several weeks.
- No symptoms in most people. Approximately 80 per cent
of people (about 4 out of five) who are infected with WNV will not show any symptoms
at all.
Incubation period for West Nile Virus is 3 to 14 days.
Is there a treatment?
There is no specific treatment yet for WNV. People with mild illness with
symptoms such as fever and aches get better on their own. Most people with severe
illness need to go to hospital for supportive treatment such as intravenous fluids,
nursing care, and for some, respiratory care.
What should I do if I think I have WNV?
Milder WNV illness improves on its own, and people do not necessarily need
to seek medical attention for this infection, though they may choose to do so.
If you develop symptoms of severe WNV illness, such as unusually severe headaches
or confusion, seek medical attention immediately. Severe WNV illness usually requires
hospitalisation. Pregnant women and nursing mothers are encouraged to talk to
their doctor if they develop symptoms that could be WNV.
As always, if you are sick and want advice, phone your physician or call the
Saskatchewan HealthLine at 1-877-800-0002.
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What about pregnant women?
- Pregnant women are not at increased risk of getting WNV.
- Insect repellents such as DEET can be used by pregnant women, but most will
choose to rely more on other measures such as protective clothing and avoiding
times and places where mosquitoes are most active. There are no reported adverse
effects from the use of repellents containing DEET in pregnant or breastfeeding
women.
- Documented cases of transmission of WNV from mother to child in the womb are
very rare. The risk to the child in the womb is unclear and is being studied.
- Pregnant women with symptoms of WNV infection should discuss the situation
with a physician.
Is there a vaccine?
There is no vaccine against WNV for people at this time.
If I get WNV once, can I get it again?
Once you have had an infection from WNV, you are likely to have long-term
immunity. This immunity may, however, wane in later years.
What you can do
Personal protection and mosquito breeding site reduction will help reduce the
risk of West Nile Virus to you and your family.
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Cover up and avoid mosquitoes
Most mosquitoes are very active at dusk and dawn. If you need to be
outside when mosquitoes are active:
- Wear protective, light-coloured clothing (long-sleeved shirts or jackets;
long pants and socks).
- Use mosquito netting on strollers to protect infants and toddlers.
- Use bug spray. To date, there are a number of federally registered
active ingredients for insect repellents. Types and concentrations of active
ingredients, duration of protection and safe usage for children vary significantly,
so read label directions carefully.
Insect repellent tips:
- Repellent does not have to be applied heavily to be effective – a light
coating will do.
- Adults should apply repellent on young children – do not let them apply
it themselves.
- Do not use repellent on open wounds, or if skin is irritated or sunburned.
Do not get it in your eyes – if this happens, rinse with water right away.
- Wash repellent off with soap and water when you return indoors or when protection
is no longer needed.
- Avoid breathing mist from a spray-type repellent. Always apply in a
well-ventilated area. Do not use near food.
- Check for skin sensitivity – apply repellent to a small area of skin
on the arm and wait for 24 hours to see if a reaction occurs.
- Store all repellents out of reach of children.
- Ask your doctor about insect repellents and see Health Canada’s web-page:
www.hc-sc.gc.ca
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Products with DEET
If using products with DEET, follow the new Health Canada guidelines.
- Adults and children 12 years and older: products containing
30% DEET provide sufficient protection. If you plan to be outdoors for a short
period of time, choose a product with a lower concentration. For example:
Concentration of DEET |
Protection Time (approximate) |
30% |
6 hours |
15% |
5 hours |
10% |
3 hours |
5% |
2 hours |
- Children between 2 to 12 years: the least concentration (10%
or less) should be used. Do not apply more than 3 times a day. Do not apply
to face and hands. Avoid prolonged use.
- Children 6 months to 2 years: in situations where there is
a high risk of complications from insect bites, the use of one application of
DEET may be considered. The least concentration (10% or less) of DEET should
be used. Everyday use should be avoided.
- Children under 6 months: DEET should not be used.
Clean up around the house and yard
Take a look around your property and get rid of mosquito-friendly places:
Any type of standing water
- Clean up and empty containers of standing water: old tires, flower pots,
wheel-barrows, barrels or tin cans, etc.
- Empty and clean bird baths once a week.
- Cover rainwater barrels with mesh or screen.
Swimming or wading pools
- Remove water that collects on pool covers.
- Make sure the pool’s pump is working properly.
- Turn over wading pools when not in use.
Check eaves and drains
- Don’t let things pile up. Clear leaves and twigs from eavestroughs,
storm and roof gutters throughout the summer.
- Make sure drainage ditches are not clogged.
- Check flat roofs frequently for standing water.
Yard and lawn maintenance
- Fill in low depressions in lawn areas.
- Cut lawn frequently.
- Turn over compost frequently
- Clear away lawn cuttings, raked leaves or other decaying debris such as apples
or berries that fall from trees.
- Clear out dense shrubbery where mosquitoes like to breed and rest.
Check windows
- Check window and door screens for holes; make sure they fit snugly into frames.
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Dead bird disposal
Have these supplies ready prior to picking up the dead bird:
- Shovel
- Gloves (heavy-duty leak-proof rubber)
- 2 garbage / heavy plastic bags. Have one bag opened
Use a shovel to pick up the dead bird and place it in double garbage bags being
careful not to puncture the garbage bags. If you can bury the bird close by, carry
it over in the shovel without putting it in bags.
Alternately you could carefully pick up the bird using heavy-duty leak-proof
rubber gloves. If gloves are not available for the handling of the carcass, several
layers of leak-proof plastic bags may be used as a glove. Grasp the body of bird
(being careful not to grasp the claws or beak) with your hand protected by the
two layers of leak-proof plastic bags and then turn the bags inside-out over the
bird so it ends up inside the bags, with your hand on the outside. Handle the
bird so that the beak or claws do not puncture the bag, gloves or your skin.
The plastic bags containing the bird should be closed tightly.
Place the bagged bird in a garbage can to be taken to the sanitary landfill
(dump). Do not dispose of it in a way that it will be handled by other people
or exposed to other wildlife. In areas with no landfill, birds should be buried
deep enough so as not to be disturbed by wild animals.
If your gloves are the re-usable type, wash your gloved hands with soap and
water before taking them off. Then wash your hands with soap and water. If a shovel
is used wash the shovel with warm soapy water and expose to sunlight.
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Find out more
As always, if you are sick and want advice, phone your physician
or call the Saskatchewan HealthLine at 1-877-800-0002.
For more information on the West Nile Virus:
Health Canada
Health Canada toll-free inquiry line:
1-800-816-7292 or 1-866-225-0709
Contact the public health unit with
your local regional health authority.
Saskatchewan Health toll-free inquiry line:
1-800-667-7766
Monday to Friday, 8 am to 5 pm.
Information on this website is from Health Canada and Centers
for Disease Control (US).
Links
Saskatchewan Labour, Occupational Health and Safety: West
Nile Virus and Outdoor workers
Saskatchewan Agriculture, Food and Rural Revitalization: West
Nile Virus in horses.
Saskatchewan Environment - Fishing
and Hunting
Canadian Cooperative
Wildlife Health Centre: Bird Pictures and Descriptions (particularly of the
crow family of birds); Reporting and Submitting Dead Birds - Saskatchewan Submission
Form; WNV Bird Surveillance Canadian Maps.
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