West Nile virus (WNV) is found in birds and transmitted by mosquitoes. Most people who are bitten by an infected mosquito will have no symptoms or have only mild symptoms. When WNV causes illness, symptoms usually appear within 2 to 15 days. In mild cases, you may have fever, headache, body aches and sometimes a mild rash.
A small number of people infected with WNV (less than 1%) will develop other serious illnesses such as meningitis and encephalitis. Meningitis is swelling of the lining of the brain or spinal cord while encephalitis is swelling of the brain itself. These conditions can cause lasting illness or death. Symptoms could include severe headache, high fever, stiff neck, nausea, difficulty swallowing, vomiting, drowsiness, confusion, loss of consciousness, lack of coordination, muscle weakness and paralysis. Anyone who suddenly gets these symptoms should seek immediate medical help. It will take 1 to 2 weeks to confirm WNV from a blood test.
The City of Hamilton is reducing the risk of WNV.
- Encouraging people to use personal protection measures such as: ensuring doors and windows have well-fitting screens in good repair; when outdoors, wearing light-coloured clothing, long pant legs, shirt sleeves and socks; using an insect repellent with DEET (N,N-diethyl met-toluamide) on uncovered skin (follow the directions carefully - get someone to translate the information if necessary - and avoid using DEET on children under 6 months old).
- Asking people to remove standing water that collects in planters, tires, roof gutters, wading pools, etc. Ask your neighbours to remove standing water around their homes, too. The City will act upon standing water complaints through the West Nile Program with Public Health, 905-546-3575.
- Trapping and testing mosquitoes to see if they carry WNV.
- Killing mosquito larvae in city roadside catch basins and in some standing water locations by using approved chemical pellets or granules.
The City will take additional protective measures if necessary.
If the risk of catching WNV is high and all other control means (such as above) have been unsuccessful, the City may spray an ultra-low volume of the insecticide malathion in some residential areas.
Health Canada's Pest Management Regulatory Agency has concluded that spraying malathion to control mosquitoes will not pose a human health concern. Malathion has been used as an agricultural chemical to control insects in Canada since 1953. It has been used for decades to control adult mosquitoes in Winnipeg.
Malathion does have a noticeable odour, even at low concentrations.
If you wish to reduce your exposure to malathion if spraying is necessary in your neighbourhood:
- Before spraying you can bring laundry, toys and pets inside, cover ponds, turn over children's wading pools and turn off external vents for fans and air conditioners.
- During spraying you can remain inside and keep windows closed to avoid odours.
- After spraying you can wash down outdoor furniture and play equipment and wash vegetables and fruit from the garden before eating.
How will I know if malathion will be sprayed in my neighbourhood?
Notices will be placed in local news media at least 48 hours before any spraying begins. Community organizations in Hamilton will be asked to post notices and help contact people.
To learn more about West Nile virus, phone the City of Hamilton at 905-546-2489 and a translator will help you. The City has a website in English, but has good information about protecting yourself and family from the virus: www.hamilton.ca/westnile.