Main Page Content

Photograph of a mosquito on human skin

What are Mosquitoes?

Mosquitoes are small insects belonging to the fly family. Mosquitoes usually lay 100-400 eggs at a time in still water. The female mosquito is the one that bites, as she needs blood to make her eggs. A mosquito bite usually results in a reaction including swelling, redness, and itchiness, and can vary from mild to severe. Although mosquitoes can bite at any time of day, they are most active between dusk and dawn (Government of Canada, 2016).

What are the health risks?

There are many health risks related to mosquito bites. There are no vaccines for many of the diseases that mosquitos can spread, so it is important to protect yourself. See below for some of the diseases transmitted by mosquitoes.

Protect Yourself and Your Family!

West Nile Virus

  • Many people will not have any symptoms.
  • Mild: fever, headaches, body aches, swollen lymph nodes, mild rash
  • Severe: quick onset of severe headache, high fever, muscle weakness, stiff neck, vomiting, confusion, paralysis
Areas: North America, Africa, Europe, Middle East, Australia, India
Important Points:
  • First confirmed case in Canada was in 2002.
  • If symptoms occur, they usually appear between 2-15 days after being bitten (Government of Canada, 2016).

Zika Virus

  • Not all people will have symptoms.
  • Fever, rash, joint pain, red eyes
Areas: U.S., Caribbean, South and Central America, Mexico, South Pacific and Oceania region, South East Asia, West Africa
Important Points:
  • Pregnant women and those planning for pregnancy should avoid travel to areas where the virus is, as it can cause birth defects.
  • Avoid sexual intercourse for 2 months (females) to 6 months (males) after travelling to high risk areas (Government of Canada, 2016).


  • Flu-like: fever, headache, chills, vomiting, diarrhea
  • If not treated quickly: seizures, kidney and respiratory failure, coma, or death.
Areas: Africa, Asia, Caribbean, Eastern Europe, South and Central America, Middle East, South Pacific and Oceania Region
Important Points:
  • Can take 1-4 weeks for symptoms to appear or up to 1 year.
  • Early treatment can reduce severe symptoms and cure malaria (Government of Canada, 2016).

Dengue Fever

Symptoms: Fever, severe headache, pain behind the eyes, joint and muscle pain, rash
Areas: Tropic and subtropic regions: Africa, Central and South America, the Caribbean, the Eastern Mediterranean, South and Southeast Asia, Oceania
Important Points:
  • Symptoms are usually absent or mild, but can quickly become severe.
  • Usually takes 3-7 days for symptoms to appear or up to 2 weeks (PHAC, 2014).


Symptoms: Sudden high fever, rash, nausea, vomiting, headache
Areas: Africa, Asia, Mexico, Caribbean, South and Central America, Pacific Islands, Southeastern U.S.
Important Points:
  • Most people recover in a week, but many report long-term joint pain.
  • Usually takes 3-7 days for symptoms to appear or up to 12 days (Government of Canada, 2016).

Fight the Bite - logo graphic

How can I minimize my risk?

  • Limit outdoor activities, especially between dusk and dawn from May to September. (But remember, mosquitoes can bite at any time of day, so always protect yourself).
  • Wear loose, light-coloured long sleeved shirts and pants with tight woven material.
  • Check and fix house screens on windows and doors to keep mosquitoes outside.
  • When vacationing, stay in well-screened, air-conditioned buildings, and sleep with a treated mosquito net.
  • Before traveling to high- risk areas, stop by a travel health clinic and visit the Public Health Agency of Canada’s website for Travel Health Notices.
  • Use repellent:
    • DEET:
      • Safe when used in correct concentrations, depending on the user’s age. (Government of Canada, 2016)
      • 6 months to 2 years: up to 10%, don’t apply more than once a day.
      • 2 to 12 years: up to 10%, can reapply up to three times daily.
      • 12+ years: up to 30%.
      • Note:
        Less than 6 months: don’t use DEET products (use a mosquito net).
        Less than 12 years: don’t use DEET daily for more than a month.
    • Icaridin:
      • Should not be used on children younger than 6 months old.
    • Permethrin:
      • Do not use directly on skin, ONLY for use on clothing and netting. Although not available in Canada, travel health clinics can provide you with information on how to purchase some before travelling.

What do I do if I have been bitten?

Most mosquito bites heal by themselves in a few days. The most common concern is controlling the itch, especially since scratching can cause infection. Ways to reduce the itch are:

  • Cool compress.
  • Topical creams like calamine lotion, non-prescription hydrocortisone cream.
  • Oral non-prescription antihistamine (Talk to your health care provider or pharmacist before taking or using any medications).

If any concerning symptoms appear after being bitten, or travelling (e.g., fever, rash, headaches, red eyes), contact your health care provider immediately.

How can the mosquito population be controlled?

Natural predators like fish, frogs, and birds, eat mosquitoes and help to keep them under control. Pest control agencies can also spray small areas with pesticides (called fogging) to help reduce the number of mosquitoes.

To reduce the mosquitoes around your home:

  • Remove standing water around your home (e.g., bird baths, flower pots, eaves troughs/gutters).
  • Keep pools clean and chlorinated, and aerate ornamental ponds.
  • For water that cannot be emptied or changed (e.g., ponds), use an approved mosquito larvicide (look for a Pest Control Product (PCP) number) that either kills larvae or stops development.
  • Keep grass cut.

For more information

To speak with a Public Health Inspector call 519-258-2146 ext. 4475.

Visit and search ‘Mosquitoes’

Other Helpful Resources:

Key References:

  • Government of Canada. (2016). Insect bite prevention. Retrieved from

  • Government of Canada. (2016). Insect repellents. Retrieved from

  • Government of Canada. (2016). Mosquitoes. Retrieved from

Related Content: