Mosquito hunters preparing to scrutinize B.C. bugs for viruses

Public health officials are ramping up mosquito surveillance after finding more evidence of a troubling virus.

It’s not your typical line of work, but specialists at the B.C. Centre for Disease Control are excitedly preparing to hunt and trap mosquitoes to see what they find – and what they might be carrying.

CTV News has learned that after years of passive observation, the agency is actively putting out high-tech traps in multiple regions for the second year in a row as climate change drives mosquitoes to newly habitable locations, potentially taking serious diseases like California serogroup viruses (CSGv) with them.

Four children were seriously sickened by the virus in 2024, prompting a 2025 study that found mosquitoes carrying the virus, though no one was seriously ill last year.

Stefan Iwasawa is a vector specialist with the BCCDC and while he typically focuses on ticks, he spent Tuesday cruising Sea-to-Sky territory with a colleague and student researcher to determine where they’d place pricey traps equipped with dry ice to attract female mosquitoes, then suck them into a trap before freezing and analyzing them under a microscope.

“It’s a great opportunity to update what kind of mosquitoes we have, and are they changing, is there anything new abundance-wise?” he said. “Because of climate change you’re going to see an increase in mosquitoes in general. So, availability of that habitat is now opening up to mosquitoes that are slowly working their way north.”

After obtaining the necessary approvals and making any necessary changes, Iwasawa and his team expect to have the traps placed and ready to snag the bugs by the end of the month. He expects analysis of what species of mosquito and whether they’re carrying any pathogens to take place in early fall.

With such a long timeline, health-care professionals are now on alert for viruses like CSGv, which the CDC designated a “reportable condition” last month.

“It’s hard to tell this year (if we’ll se CSGv cases) and really it just depends on so many things, including the habitat for the mosquitoes, what mosquitoes might have come into the region, whether the virus survives throughout the winter,” explained Dr. Ceinwen Pope, a medical health officer with Vancouver Coastal Health assigned to the Sea-to-Sky region.

She said that typically most people wouldn’t even have symptoms if an infected mosquito bit them, or that they would be mild and easily cleared by the body’s immune system. But if someone becomes confused, feverish with a headache, or loses control of their limbs, it’s time to seek emergency medical attention.

“The risk of getting severe illness from California serogroup virus or other mosquito-borne diseases is low,” said Pope. “People should continue to go outdoors, enjoy nature, but you can take some simple measures to protect yourselves against mosquito bites when you’re out there.”

That includes light-coloured, loose clothing, and insect-repellent. Health officials are also urging homeowners to avoid letting standing water gather around their homes as it can be a breeding ground for the pests, which are considered the world’s deadliest animals on a global basis.