Disease-carrying mosquito reaches B.C.


BURNABY, B.C. – A species of invasive, disease-carrying mosquito has been found in British Columbia — the first such discovery in Western Canada.

A team from Simon Fraser University, along with workers at a mosquito control company, discovered larvae of the aedes japonicus in standing water in Maple Ridge, a suburb east of Vancouver.

A report published in the Journal of Medical Entomology said researchers believe the mosquito could be a significant threat to the health of humans and domestic animals.

“The ability of these species to survive and spread rapidly is well documented by its history in Europe,” the study said.

The mosquito has the potential to transmit several diseases, including West Nile virus, varieties of encephalitis and dengue fever.

The study said it has been infected in the lab with nine different pathogens, including chikungunya, an illness found in Caribbean countries that causes fever, muscle and joint pain and stiffness, headache and rash.

Study co-author and retired SFU professor Peter Belton said researchers have been waiting for the mosquito to arrive since the insects were discovered in Washington state 14 years ago.

“They haven’t done any dangerous transmission of diseases in Washington,” he said. “But global warming could very well bring up some nasty viruses. They’re good at transmitting viruses, we know that.”

The larvae was first found in a tarpaulin in July 2014, and when researchers returned to the same area in 2015, they found the larvae had survived a relatively mild winter.

The batch of eggs was resistant to freezing and drying, the study said.

This past May, a researcher caught and photographed a female in “pristine condition” in the neighbouring municipality of Mission.

“They’re covered in scales, that’s what gives them the gorgeous golden stripes,” Belton said.

Had the female been flying for a few days, many of the scales would have rubbed off, so it means the species has been found in more than one place in the Lower Mainland, he added.

Belton said the larvae appears to be extremely hardy.

“That’s how they got worldwide in about 20 years,” he said.

The breed, also known as the Asian bush mosquito, is native to Asia but has been found in Eastern Canada and many U.S. states. A sub-species has been discovered in Oregon and Washington states.

Researchers are now studying the B.C. insects to pinpoint their place of origin.

“We conclude that (the mosquito) is established in the Lower Mainland of British Columbia and that it is unlikely to have arrived here, since it was found in Washington in 2001, without human intervention,” the study said.

Belton said researchers believe someone likely brought the mosquito to B.C. in a used car tire or on a tarp as an egg, and it then spread.

Other than repellents, the easiest way to get protection is to control the population, he said.

“They should be able to find out where they’re breeding. We have a bacteria that are very specific that can control the larvae.”