West Nile virus season still bites across Canada

Property managers should not ignore low-risk season, experts say
Thursday, September 4, 2014
By Rebecca Melnyk

Recent findings of infected mosquitos should remind property owners to implement protective measures against the spread of West Nile virus. Even as summer ends and the traditional infectious season tapers off, the risk of contracting the virus remains.

With hot weather arriving late this year in Ontario, Quebec, Saskatchewan, Manitoba and Alberta—provinces where the virus-infected species normally thrive in high temperatures—these blood-thirsty mosquitos slowly emerged from hibernation to breed new generations.

As of August 16, 2014, the Public Health Agency of Canada (PHAC) reported that 51 mosquito pools, three birds and two horses tested positive. During the last week of August, virus activity around the country increased as Toronto Public Health found virus-infected mosquitos among 43 traps placed around the city, while Manitoba Health officials confirmed this year’s first human case of West Nile in a Winnipeg man.

But even though the season—ranging from mid-May to the first frost of October—isn’t as dangerous as that of 2012, when PHAC reported 450 human cases, some experts advise property managers shouldn’t ignore the low-risk season.

“As long as we have mosquitos out there, there’s always a risk,” says Philip Curry, entomologist and West Nile coordinator for the Saskatchewan Ministry of Health. “This risk is particularly higher on these warmer days when mosquitos are active and biting.”

In southern parts of Saskatchewan, where there’s currently a moderate probability of infection, Curry says the early summer floods contributed to the risk.

“Flooding does certainly increase the available habitat for mosquitos and we do see high numbers,” he says, adding, “but we haven’t had the hot weather to really increase the number.”

Still, according to Curry and the Government of Saskatchewan, since the virus first entered Canada in 2002, it’s never left, fluctuating year by year. In all cases, there are certain precautions to apply in both rural and urban areas.

Standing water

Stagnant water—water that’s been sitting for seven days or longer, no matter what volume—is comfortable breeding ground for mosquito larvae. Pool covers, where water collects on top, should be maintained, while rain barrels can be covered with tight lids or screens.

Aeration pumps should be installed on ornamental ponds and water gardens, while the area around downspouts must be tightly sealed. Water pooling in areas where it’s less likely to evaporate quickly, such as under decks or playground equipment, should be properly drained.

Around the property

Old tires, in which pools of water can accumulate, should be stacked, covered and placed in an area without grass or shrubbery. However, if tires are part of the landscape, holes can be drilled in the bottom to promote drainage. Septic tanks and landscape discharge areas should also be pumped to guarantee proper drainage. Also, regularly clear yard debris and empty eavestroughs.

Window screens and doors should be in good repair to block mosquitos entering buildings at night. Doors should also swing outward to push mosquitos away rather than pulling them inward

Rebecca Melnyk is online editor of Building Strategies & Sustainability and Canadian Property Management.