Critics reject doctors' call for end to Winnipeg mosquito fogging

A physician group's suggestion that Winnipeg stop fogging for mosquitoes has spurred heated resistance from some residents and other health professionals.

A physician group's suggestion that Winnipeg stop fogging for mosquitoes has spurred heated resistance from some residents and other health professionals.

The Canadian Association of Physicians for the Environment (CAPE), urged the city on Monday to stop using the controversial insecticide malathion, saying its health risks are too great.

The Toronto-based group, made up of several hundreds physicians across the country, said malathion has been linked to a number of diseases, including nerve and lung damage and childhood leukemia.

But many Winnipeggers, who are suffering through one of the worst mosquito years in memory, responded that they'll take their chances.

Laura Stewart said the insects have been particularly intolerable for young children, like her five-year-old daughter Hannah.

"They were so bad, my daughter literally dropped on the floor where there was dirt, and she was rolling around," Stewart said. "And she was trying to get them off."

While not a fan of mosquito fogging, Stewart said it was better than the alternative – risking infection with West Nile virus.

In mid-July, the province declared a health emergency and ordered city-wide fogging after it discovered rising numbers of mosquitoes infected with the West Nile virus. It has also ordered malathion fogging in several rural communities for the same reason.

However, the issue of malathion fogging has sparked fierce debates and public protests in Winnipeg, which is one of the only large communities in Canada that uses the chemical for nuisance mosquitoes and not just when the virus looms.

'We think it's overkill'

CAPE's executive director, Gideon Forman, said that using malathion to kill mosquitoes is like shooting them with an elephant gun.

"We think it's overkill. I mean, malathion is a very, very toxic organophosphate pesticide," Forman said. "If you look at the science, if you look at the peer review journals, there's some very damning evidence about malathion."

Forman said the group recognizes that adult mosquitoes can pose a risk of West Nile virus, but does not think malathion is the answer.

The news release from CAPE said fogging may not even work, pointing to studies from New York state that found "over 11 years, spraying led to a 15-fold increase in mosquito counts, probably due to increased pesticide resistance but mostly due to the obliteration of predator species."

"We realize that there is a danger with West Nile, and we don't want to minimize that for a second," said Forman.

"But what we're saying ... is a more reasonable response than fogging would be an aggressive campaign to attack mosquito larvae."

Other health groups say not spraying is more risky

The group's contentions were quickly disputed by some Manitoba physicians and health officials, who argue that the risks of not spraying are potentially worse than any dangers posed by malathion.

Dr. Susan Roberecki, deputy medical officer with Manitoba Health – which has ordered several municipalities to spray with malathion – said the research CAPE is using is old.

She said she's heard arguments against the use of malathion many times before. But she said with West Nile virus a real threat this year, it's worthwhile to use the chemical to spray for adult mosquitoes this summer.

"There's a lot of opinions on mosquito control in Manitoba, and this is one of the ones that we've heard before, and take seriously," she said.

"And we take our decisions to use and recommend adult control seriously."

The Manitoba Medical Association hasn't specifically studied malathion, but the association's environmental health committee said the risk of West Nile virus makes the chemical's use worthwhile.

Pediatrician Barry Bermack agreed, saying that he sees children with infected mosquito bites all the time.

"Just like in other medical things, you have to decide which is worse, treating or not treating," he said.

He said he's comfortable with public health officials' decision that fogging was safer than not fogging.

The Manitoba College of Family Physicians said it supports a policy of minimal pesticide use, but not an outright ban.

The federal government conducted a review of malathion's use in 2003 and deemed the nerve toxin safe for use in residential fogging campaigns to control adult mosquitoes.

Opponents of malathion's use say the nerve toxin can weaken the immune system and cause a variety of health problems, including cancer and birth defects.