Toronto Public Health has confirmed the city’s first human case of West Nile virus for 2026. The case involves an adult resident and follows the detection of West Nile virus-positive mosquito pools in several Ontario regions, including Toronto, York Region, Halton, Belleville, and Windsor-Essex.
While most people infected with West Nile virus experience mild symptoms or no symptoms at all, the virus remains an important travel and public health concern during mosquito season — Ottawa saw its own first positive mosquito detection around the same point last season.
What Is West Nile Virus?
West Nile virus is a mosquito-borne infection transmitted through the bite of infected mosquitoes. Mosquitoes become infected after feeding on infected birds and can then spread the virus to humans and other animals.
The virus is commonly found throughout North America during the warmer months, particularly from late spring through early fall.
Symptoms of West Nile Virus
Symptoms usually appear between 2 and 14 days after being bitten by an infected mosquito.
Common symptoms include:
- Fever
- Headache
- Body aches
- Fatigue
- Nausea and vomiting
- Skin rash
- Swollen lymph nodes
- Stiff neck
Most people recover completely within days to weeks.
Who Is at Higher Risk?
Certain individuals are at greater risk of severe complications, including:
- Adults over 60 years of age
- Individuals with weakened immune systems
- People with chronic medical conditions such as diabetes, kidney disease, or cancer
In rare cases, West Nile virus can cause serious neurological complications such as:
- Encephalitis (brain inflammation)
- Meningitis
- Muscle weakness
- Paralysis
What Travellers Should Know
West Nile virus is found in many popular travel destinations across Canada, the United States, Europe, Africa, the Middle East, and parts of Asia.
Unlike some mosquito-borne diseases, there is currently no vaccine available for West Nile virus for travellers. Prevention focuses on avoiding mosquito bites.
How to Protect Yourself
Whether you’re spending time outdoors in Ontario or travelling abroad, consider these preventive measures:
Use effective insect repellents. Health Canada-approved repellents containing DEET or Icaridin (Picaridin) provide excellent protection against mosquito bites.
Dress for protection. Wear long sleeves, long pants, socks, and light-coloured clothing — especially during dawn and dusk when mosquitoes are often most active.
Eliminate standing water. Mosquitoes breed in stagnant water found in bird baths, flower pots, gutters, buckets, and outdoor containers.
Use physical barriers. Ensure window and door screens are intact, sleep in screened or air-conditioned accommodations when travelling, and use mosquito nets where appropriate.
Travel Medicine Perspective
West Nile virus is one of several mosquito-borne illnesses travellers may encounter. Depending on your destination, travellers may also be at risk for dengue fever, chikungunya, malaria, yellow fever, Japanese encephalitis, and Zika virus. Each destination presents unique risks that may require specific vaccines, medications, or preventive measures.
Why a Travel Health Consultation Matters
At Destinations Travel and Immunization Clinic (DTC), our travel medicine practitioners provide comprehensive risk assessments that go beyond routine vaccine recommendations.
During your consultation, we review your destination-specific health risks, seasonal mosquito and insect-borne disease activity, recommended travel vaccines, malaria prevention options, personal medical conditions and medications, strategies to prevent mosquito bites and other travel-related illnesses, and food, water, and environmental health risks.
Whether you’re travelling across Canada, visiting the United States, or planning an international adventure, understanding local disease risks helps you travel more safely and confidently.
Mosquito-borne illnesses continue to emerge in many parts of the world. A pre-travel consultation can help you understand your risks and take appropriate preventive measures before departure. Contact Destinations Travel and Immunization Clinic today to prepare for safe and healthy travel.
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The medical information on this site is provided as an information resource only and is not to be used or relied on for any diagnostic or treatment purposes. This information does not substitute for professional diagnosis and treatment. Please do not initiate, modify, or discontinue any treatment, medication, or supplement solely based on this information. Always seek the advice of your health care provider first. Full Disclaimer