small font | large
Select a topic link or scroll down to view them all:
Summer in Saskatchewan is a great time for everyone to get outside and enjoy the sunshine and warm temperatures. However, it is also the time of year when we most frequently come in contact with mosquitoes. Some of the mosquitoes found in the Saskatoon Health Region can carry West Nile Virus (WNv) that may cause serious disease in people and pets.
Saskatoon Health Region did not experience many cases in 2008, 2009 or 2010. In 2007, however, the Region experienced a record year for WNv cases. Between July and November there were 357 confirmed human cases in the region including 22 neurological, 333 fevers and 2 asymptomatic cases. Provincially, the number of people infected with WNv in 2007 surpassed the previous record as well.
WNv is transmitted by bites from infected mosquitoes. Less than one in a hundred mosquitoes in a given area will carry the disease, and less than one in a hundred people bitten by an infected mosquito will develop serious symptoms. However, it is important to remember that if you do become infected the result could be serious.
This information sheet provides a quick print out of general West Nile Virus information:
Symptoms of WNv
People who do become infected with West Nile virus can experience mild symptoms including:
- body aches
- occasionally, skin rash and swollen lymph glands.
More severe symptoms may occur and could include:
- high fever
- neck stiffness
- muscle weakness
- in rare cases, death
What is West Nile Virus?
West Nile virus is a virus that can cause disease in people, birds and horses. This virus first appeared in North America late in the summer of 1999 in New York City. West Nile Virus was first recorded in humans in Saskatchewan in 2003.
A person or animal can be infected with WNv:
- through the bite of an infected mosquito;
- evidence has shown that a pregnant woman can pass WNv to her unborn baby. The virus can also be passed to an infant through breast milk;
- it is rare that the virus is passed through a blood transfusion.
Spread from animal-to-animal and animal-to-human does not appear to occur.
Symptoms can begin 3 to 5 days after being bitten by an infected mosquito. Symptoms of WNv include:
- flu-like symptoms such as a fever, headache, muscle aches, swollen lymph nodes and skin rash;
- or, more serious symptoms include severe headaches or fevers, neck stiffness, muscle weakness and confusion.
- most people infected with WNv have no symptoms.
People who have onset of severe symptoms should seek medical care. Antibiotics are not useful in the management of WNv.
What can I do to prevent infection?
To reduce the risk of West Nile Virus infection, everyone can take some simple precautions:
- wear light coloured, loose fitting clothes with long sleeves and pants when spending time outside especially at dusk and dawn
- use mosquito repellent that contains DEET when you are outdoors, especially at dawn and dusk
- do not use DEET on infants less than 6 months
- choose 10% DEET or less for children aged 6 months–12 years;
- age 6 months–2 years: apply once a day, avoiding hands and face
- age 2-12 years: apply no more than 3 times a day, avoiding parts of the hands which may have contact with the eyes or mouth
- choose up to 30% DEET for 12 years and over
- pregnant and nursing mothers consult your physician
- make sure that window and door screens fit tightly and are free from holes
See the following information sheet for precautions to take with mosquitos:
A small amount of standing water will serve the purpose for mosquitoes to breed. Mosquito eggs and larvae can develop in any amount of standing water if left for more than 4 days. To prevent this from occurring:
- drain any standing water (such as old tires, wading pools, eaves troughs). Empty and clean bird baths twice a week.
- aerate ornamental ponds and stock with that fish that eat mosquito larvae
- cover rain barrels with screens. Mesh size should be
less than 1.5 mm.
- keep grass cut short
- keep swimming pool covers free of standing water
In addition to these preventative measures, some products are available to help control mosquito populations. These include:
- Bacillus thuringiensis var. israelensis (B.t.i.) (Trade names: Aquabac, Vectobac, Teknar), is a naturally occurring bacteria with insecticidal properties. Bti will only kill mosquitoes and not harm other insects or animals
- Altosid® is an insecthormone that will disrupt the development of insect larvae. It will remain active in the water for more time than the Bacterial product, but will kill other aquatic insects so care must be taken to avoid environmental contamination.
- Insecticidal soap can also be applied to water and will successfully kill any larvae or pupae present.
Camping and WNv – Things to Keep in Mind
Remember that the West Nile Virus is spread through mosquito bites. It is summer time and a lot of you will be outdoors. Here a few helpful tips to prevent mosquito bites when camping:
- Mosquitoes are attracted to dark colours like black and navy. When outside during the day, wear light coloured clothing like beige or khaki. Wear insect repellent (which contains DEET) or a mesh bug jacket.
- Mosquitoes are most active at dawn, during the night and at dusk, or in shady, wooded areas during the day – so remember to cover up. At the end of the day or if going into wooded areas, take the time to put on long-sleeved shirts and pants and/or use insect repellent.
- Mosquitoes like to sleep where you sleep. Remember to zip the tent door closed or keep the screen door closed on the trailer. At night before falling asleep, use the flashlight to look for those mosquitoes that got into your tent or trailer. Make a game of it, hunt them down and squish them.
- Mosquitoes are attracted to the carbon dioxide in exhaled breath, as well as movement, body odours and heat. Remember this when doing outdoor activities. Bring the repellent on those long hikes or portages and reapply it as necessary.
Information for Professionals
- Case Reporting Form for Health Care Provider: MS Word | PDF
For more information on WNv contact:
- Public Health Services-Disease Control in Saskatoon at
- The provincial West Nile Virus coordinator, Phil Curry at
West Nile Virus Surveillance