Invasive Mosquitoes Carrying Dangerous Virus Found in B.C.'s Sea-to-Sky Region
British Columbia health researchers are sounding the alarm after discovering two invasive mosquito species in the province's scenic Sea-to-Sky region — and both tested positive for a virus that can cause serious neurological illness in humans.
The mosquitoes were found to carry California serogroup virus, a group of mosquito-borne pathogens known to cause encephalitis (brain inflammation) and meningitis. While infections in humans are relatively rare, they can be severe, particularly in children and immunocompromised individuals.
What Is California Serogroup Virus?
Despite its name, California serogroup virus is not exclusive to California — it's a family of viruses that includes several strains, such as La Crosse virus and Jamestown Canyon virus, found across North America. The viruses are transmitted through the bite of infected mosquitoes and cannot spread person-to-person.
Symptoms can range from mild flu-like illness to serious neurological complications. Most healthy adults recover fully, but health officials stress that early awareness and mosquito bite prevention are key to reducing risk.
Invasive Species, New Risks
What makes this discovery particularly concerning is the species involved. These are not mosquitoes historically native to B.C.'s mountain corridor — their presence in the Sea-to-Sky region, which stretches from Vancouver through Squamish and Whistler to Pemberton, suggests that invasive species are expanding their range, possibly driven by shifting climate patterns and warmer temperatures.
Researchers are continuing to monitor mosquito populations in the region and are urging residents and visitors — especially those heading to popular outdoor destinations like Whistler — to take precautions during peak mosquito season.
How to Protect Yourself
Public health officials recommend the following steps to reduce mosquito exposure:
- Use insect repellent containing DEET, picaridin, or IR3535 on exposed skin
- Wear long sleeves and pants during dawn and dusk, when mosquitoes are most active
- Eliminate standing water around your property, including in planters, birdbaths, and gutters
- Use window and door screens to keep mosquitoes out of your home
- Seek medical attention if you develop fever, headache, stiff neck, or confusion after being bitten
A Growing Concern Across Canada
This discovery fits into a broader pattern of mosquito-borne disease risk expanding across Canada. West Nile virus, another mosquito-transmitted illness, has been documented in Ontario and Quebec for years, and climate scientists have long warned that warming temperatures could allow disease-carrying insects to establish themselves in regions where they previously couldn't survive.
For Canadians planning outdoor adventures this summer — whether in B.C.'s mountains or Ontario's cottage country — staying informed and taking basic precautions remains the best defence.
Source: CBC News — Virus detected in invasive mosquitoes found in B.C.'s Sea-to-Sky region
