MEMORIAL UNIVERSITY
Changing climate, changing risk: mosquito research shows human-transferrable viruses in province

A mild winter resulting in a warmer-than-usual summer might be good news for sun worshippers.

However, it could lead to an increased mosquito population this year, which might be bad news for public health.

Researchers at Memorial University recently released their findings of a years-long study that saw residents of Newfoundland and Labrador and St. Pierre-Miquelon collect mosquitoes and submit them for identification and testing.

The project team came together in 2019. It included Dr. Atanu Sarkar, a public health specialist from the Division of Population Health and Applied Health Sciences in the Faculty of Medicine; Drs. Andrew Lang and Marta Canuti, both virologists; Dr. Tom Chapman, an entomologist; and Kate Carson, a mosquito identification expert, all with the Department of Biology, Faculty of Science.

Also on the team were Dr. Joel Finnis, a climate scientist from the Department of Geography, Faculty of Humanities and Social Sciences; Dr. Hugh Whitney, a retired chief veterinary officer with the Government of Newfoundland and Labrador; and biology graduate students Tegan Padgett, Lucas Hollett, Courtney White, Claire Brenton and Jordan Wight.

Mosquito-borne viruses

Volunteer citizen scientists provided the team with a cost-effective method of collecting samples that were used to build a provincial database of native and invasive species that also monitors mosquito-borne viruses over a large geographic area.

"This is the first time an extensive profile of the province was done," said Dr. Sarkar. "Residents collected samples from coast-to-coast throughout 2019 and into 2020 until the pandemic began."

By that point, the researchers had already discovered that some of the sampled mosquitoes carried diseases that could be transmitted to humans, specifically the snowshoe hare virus (SHV), the Jamestown Canyon virus (JCV) and a new virus suspected to be a JCV-like hybrid.

While Canada is not typically a high-risk region for most mosquito-borne diseases, changes in weather and climate have impacted mosquito habitats in recent years.

Many mosquito-borne diseases have similar symptoms.

The most common are fever, fatigue, headache, nausea, vomiting and rash.

However, in serious cases, people may develop inflammation of the brain, spinal cord or the membranes that protect the brain and spinal cord, resulting in conditions such as encephalitis, myelitis and meningitis.

The team had planned to do more intensive work in the areas where mosquitoes had been collected, but then their labs were locked down alongside everything else.

"Family physicians and nurse practitioners may need to be more vigilant if they are in an area where the virus has been identified." Dr. Atanu Sarkar

When we reopened, many of the student researchers working on the project had graduated, so the team had to recruit and train new people.

"By that time, we had gotten disconnected from our citizen scientists. But we were determined to see the project through," Dr. Sarkar said.

Public health implications

With the information now publicly available, Dr. Sarkar is hoping other researchers will be able to build on the work they have started.

"Because of the extensive data we have collected, they'll be able to do their own work," he said. "We have also created a map indicating where you can find every species. It's a strong database and people can do a lot with it."

Dr. Sarkar is now investigating the public health implications of having mosquito-borne illnesses in the province.

"We now know we have species of mosquito that can carry viruses in the province, and we know that some actually do carry it and people are getting bitten. Family physicians and nurse practitioners may need to be more vigilant if they are in an area where the virus has been identified."

Dr. Sarkar recommends that people living in high-risk areas wear mosquito repellent or cover up when outside and not take mosquito bites lightly.

"We hardly get a summer in Newfoundland and Labrador, so we can't deprive people from going outside, but they can take precautions," he said. "It's also important to keep your property clean and get rid of garbage or any standing water where mosquitos can breed.

"Just because we are on an island and have a prolonged winter doesn't mean we are safe," he added. "The mosquitos are here, and human cases can happen any time."