West Nile Virus in Niagara

Reduce the risk

Get tips and prevention for West Nile Virus for you and your family

Best ways to reduce the risk

West Nile Virus is spread to humans by the bite of an infected mosquito. A mosquito can become infected by biting an infected bird.

The virus is not transmitted through casual contact from others, such as kissing or touching.

A very small number of cases have been infected by blood transfusion, breast milk, organ transplant from an infected donor, and during pregnancy from mother to baby.


Only 20 per cent of infected people will show any symptoms, which usually appear three to 14 days after an infected mosquito bite.

Most symptoms will be mild and may include:

  • Fever / headache
  • Nausea / vomiting
  • Body aches
  • Possible skin rash (below neck and above waist)
  • Swollen lymph glands

About one in 150 infected people will have a severe infection that may include:

  • Headache / high fever
  • Neck stiffness
  • Disorientation
  • Coma / unconsciousness
  • Tremors / convulsions
  • Muscle weakness / paralysis

These symptoms may last several weeks. Some effects may be permanent.


For general questions about the virus, call 905-688-8248 or toll-free 1-888-505-6074, ext. 7590, Monday to Friday, 8:30 a.m. - 4:30 p.m.

Treatment on private property

To authorize the treatment of a municipally-owned catch basin on private property, complete an authorization for access to catch basin.

Report a dead bird

Submit a wildlife submission form to report a dead bird or sighting of sick or dead wildlife.

Zika virus

Learn about Zika virus symptoms and treatment and your risks if travelling.

Detection and treatment of the virus

The virus can be confirmed in humans by testing the blood or fluid that surrounds the brain and spinal cord.

There is no specific treatment, medication or vaccine for West Nile Virus. In the most severe cases, hospitalization is required for management of symptoms and intensive, supportive care.

Get statistics about West Nile Virus in Niagara and Ontario.

Reduce the risk of West Nile Virus

The best ways to reduce the risk of infection are:

  • Reduce standing water where mosquitoes like to breed
  • Avoid infested areas
  • Wear long sleeved shirts, long pants, hats, socks and shoes.
  • Repair damaged doors and window screens.
  • Use an insect repellent that contains DEET or Icaridin. Always follow the manufacturer's instructions

How to reduce mosquito breeding areas around your home

Mosquito larvae can develop in water that has been standing for more than four days.

  • Keep your yard clean

    Our values guide the committee's decision making and actions:

    • Remove discarded tire and clean up junk piles that collect water
    • Cover containers or use lids to prevent water from collecting in the bottom of garbage cans
    • Use screen or fine mesh to cover rain barrel
    • Clean pet food and water bowls and store indoors when not in use
  • Clean out eaves, gutters and drains
    • Clear leaves, twigs and debris from eavestroughs, storm and roof gutters throughout the summer
    • Make sure drainage ditch is not clogged
    • Check flat roofs frequently for standing water
  • Maintain yards and lawns
    • Fill in low depressions in lawn areas
    • Eliminate standing water in gutters or storm drains to prevent small ponds
    • Install screens over catch basins
    • Grass clippings, leaves or other decaying debris, such as apples or berries that fall from trees should be mulched to prevent organic matter from going into catch basins or storm sewers as food source for mosquito larvae
    • Turn over compost frequently
  • Always inspect swimming or wading pools and ponds
    • Remove water that collects on pool covers
    • Make sure the pool's pump is circulating water
    • Turn over wading pools when not in use
    • Use a pump to circulate water in your pond
  • Eliminate stagnant water where mosquitoes lay their eggs
    • Clean up and empty water in toys, birdbaths, tires, flowerpots, wheelbarrows and other garden objects
    • Drill holes in the bottoms of containers so water can't collect
    • Change water in bird bath frequently
  • Repair window screens and screen doors
    • Check window and door screens and repair any holes
    • Ensure screens fit tightly into to window or door frames to prevent mosquitoes from getting inside
    • If you don't have screens, try and keep windows closed between dusk and dawn
    • Install screens on crawl spaces and attic vents
  • Fix faucets and hoses
    • Repair any leaks to faucets and hoses to prevent possible breeding sites
    • Prevent water from pooling around downspouts and air conditioners

Larvicide for mosquito control in Niagara

Storm drain

High-risk areas in each city / town in Niagara are treated during the summer to help control mosquitoes. These areas include storm drains and sections where water collects and remains.

Storm drains are painted with a pink, white and blue dot to show it's been treated with larvicide.

  • Larvicide: BTI (Bacillus Thuringiensis Israelensis)

    The larvicide we use is in the form of pellets, which dissolve in water. This chemical is effective to kill mosquitoes in the early stages of their life, rather than using a pesticide to kill adult mosquitoes.

    The larvicide we are using this season is BTI (Bacillus Thuringiensis Israelensis), which has been approved for mosquito control by Health Canada.

    Bacillus Thuringiensis Israelensis contains a natural bacterium that kills mosquitoes during their larval stage of development. It has been used effectively since 1982 for insect control, particularly for mosquitoes, black flies and fungus gnats, and is commonly found in soils in Canada and throughout the world.

    The larvicide is placed in areas of standing water where mosquitoes breed, such as ditches and shallow ponds. It effects the mosquito larva's ability to eat, causing the larva to starve to death.

  • Larvicide poses no risk to humans

    Health Canada has determined that Bacillus Thuringiensis Israelensis poses no health risks to humans or mammals when applied properly. The toxins only work in certain insects' digestive systems. Human and animal stomachs are too acidic to the larvicide to work.

    As well, we treat areas that are inaccessible to the public, such as down sewer drains.

    Direct contact may cause mild skin and eye irritation. Children and pets should avoid areas that have been treated.

    If a person comes in contact, a concentrated exposure could cause mild skin and eye irritation. Rinse the eyes with tap water for 20 minutes and wash the skin thoroughly with soap and water. If the symptoms persist, seek medical attention.

    For more information about larvicides, visit Health Canada's Pesticides and Pest Management.

  • Notice of application

    From May 13 to Nov. 1, 2024, Niagara Region will conduct a larviciding program in all 12 Niagara municipalities under the authority of the Medical Officer of Health. The program helps to control larval mosquitoes and prevent their development into carriers of West Nile Virus.

    The larvicide Altosid Pellets (PCP No. 21809, pellet), Mosquiron 0.12CRD (PCP No. 31079, ingot) or VectoLex WSP (PCP No. 28009, pouch) will be applied by direct hand application into municipal catch basins. The larvicide VectoBac 200G (PCP No. 18158, granular), VectoBac 1200L (PCP No. 21062, liquid) may be placed by direct hand application into selected bodies of surface water such as ditches and ponds, depending on the results of testing for the presence of mosquito larvae.

    All larvicides will be applied by Ministry of the Environment, Conservation and Parks licensed applicators or technicians.

    For information about the larvicide applications, call Pestalto Environmental Health Services at 1-866-648-7773.

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