Overlooked algae may be West Nile link

Hard on the heels of the provincial government’s much-criticized plans to combat the West Nile virus this summer, an Oakville town councillor is raising new questions about another possible concern that may have been overlooked by public health officials.

Allan Elgar wants to know whether there’s any link between the large, stinking green mats of algae that formed along the Oakville lakefront last summer and the alarming rate of West Nile virus infections in the area.

“What really flagged it was when I looked at the [infection] map and saw that [the areas with the highest incidence of West Nile virus] were the same areas that were having problems with rotting algae,” Elgar says.

Southwest Oakville and southeast Burlington — an area plagued by algae problems last summer — also had one of the highest rates of West Nile infection in North America in 2002.

Elgar believes the algae was caused by phosphorus that got into the lakefront waters from more than one source.

The first source, he thinks, was outfall pipes from a local sewage plant.

But the second source could have been fertilizer applied either to lakefront parkland or to the large, affluent properties in the district. “Phosphorus is coming from somewhere beside the sewage treatment plants,” says Elgar.

“Let’s face it, fertilizers have a phosphorus base.”

Talk about a link between phosphorus leachate, algae, mosquito breeding habitat and West Nile is not new, though if Elgar is right, the severity of that link could possibly have been greatly underestimated.

Janet May, a campaigner for both Pesticide Free Ontario and the Toronto Environmental Alliance, agrees with Elgar that the coincidence between algae and the disproportionate number of cases of West Nile bears further investigation.

“Yes, definitely there’s a connection. It’s very clever of the councillor to have noticed it,” she says.

“Wherever you see algae it tends to indicate swamp-like conditions and that’s a perfect breeding ground for mosquitoes… I would suggest that this is something public health authorities should be considering in their approach to West Nile.”

May concurs that lawn fertilizers could be a large source of the algae problem, and that not alerting people to such dangers is one of the ways authorities in the provincial health ministry have let the public down.

“There’s a lot of things the province could be doing, and I think they’ve really dropped the ball on this,” May says.

“There’s been no public education campaign, no helping people to understand what they can do to protect themselves. We should be getting the word out, but what’s been done has been abysmal.”

Elgar stumbled across the possible link accidentally. He’d been investigating algae problems that have plagued the Oakville and Burlington lakefronts for the past two years. Elgar undertook that research mainly because of the algae’s stench.

“The problem essentially is that the smell is so bad that it’s making people sick to their stomachs all along the lakefront,” Elgar says.

Last summer, work crews tried physically removing the algae, but that proved ineffective. Halton region has since set up a 14-member committee to investigate the matter.

It wasn’t until Elgar recently looked at a map from Halton region’s medical officer of health showing the concentration of cases of West Nile virus in Oakville that he noticed the vast bulk of incidents of the disease occurred in the areas along the lakefront where the algae was the worst.

The realization prompted Elgar to call up experts he met at an algae symposium in May, 2002, who agreed that the possible link deserved further investigation. He thinks the implications are twofold.

“I think we should start to lean toward a long-term approach [to West Nile] rather than take a knee-jerk approach,” Elgar says, noting that sewage treatment plants feed phosphorus into near-shore waters, contributing to algae growth.

“And in the short term, we need to make sure that the algae isn’t sitting there rotting.”

He wants health officials to investigate whether there’s a connection between the two environmental issues. Should there be a causal link, it will add a new dimension to Ontario’s increasingly outraged debate about West Nile prevention.

For one, it could assuage west-GTA residents’ nervous puzzlement about the reasons why Oakville appears to be a new North American ground zero for the virus.

Second, the issue raises larger questions about whether man-made chemicals leaching into local waterways shouldn’t be far more of a concern for Ontario residents, and a far larger part of public education efforts around the province.

Charles Knauf, an environmental health analyst with the Monroe County Health Department in Rochester, New York, wrote Elgar that he’s heard from experts that algae mats could be a good breeding grounds for larvae.

His department will be watching algae accumulations this summer, he wrote, and thinks the mats would be worth sampling.

“I should also add that the mats could be good breeding habitat for other mosquito species, especially Anopheles species, that do not have a breathing tube and lie with their abdomens in the surface film to breathe,” he wrote.

“While they have not been implicated as major vectors by positive adult pools of species, there have been a few positive pools of Anopheles quadrimaculatis and Anopholes punctipennis over the last few years.

“This is a huge phenomenon about which very little is yet really known, so it is wise to investigate as many avenues as resources will allow.”

On March 22, Ontario Health Minister Tony Clement announced a seven-point plan for battling the spread of West Nile virus this summer, including doubling last year’s $9 million in spending for public education programs, improved testing for the disease and controlling larval mosquito populations.

The program was expected to be confirmed in the province’s March 27 budget.

Critics of Clement’s plan say it amounts to too little, too late, and that delays in preparing to combat the spread of West Nile may lead to ill-advised deploying of pesticides and larvicides when other tactics, especially public health campaigns, would be more effective.

The West Nile virus first appeared in North America in New York state in 1999, settling into the greater Toronto area last summer. Ontario’s health ministry says that there have been 305 confirmed and 82 probable cases cases of West Nile infection in the province so far, and one death has been conclusively linked to the disease.

In addition to the things provincial and municipal authorities could be doing, May says that people can take several steps to combat mosquito populations around their own homes, such as avoiding pesticides and lawn fertilizers, clearing out eaves troughs and pool covers, and disposing of rubber tires and other still water reservoirs on their property.

“Even an overturned beer cap filled with water can be a breeding ground for mosquitoes,” May says.

Originally published in Eye Weekly on March 27, 2003.