Soggy spring fuelling mosquito boom, health unit warns
Brace yourself for a mosquito baby boom. Southwestern Ontario’s cool, rain-soaked spring weather — and no prolonged wintertime cold snap — is setting the stage for an onslaught of the itch-inducing insects, just in time for patio season, the local health unit says. “With the wet spring, we will probably have more mosquitoes. But they’re the non-vector ones — the ones that can’t transmit the West Nile virus,” said Jeremy Hogeveen, vector-borne disease co-ordinator for the Middlesex London Health Unit.
Like weather forecasting, it’s difficult to predict exactly how this year’s mosquito season will shake out, Hogeveen said. There are mosquito larvae out now that won’t become biting adults until early June, and also dormant mosquitoes that hunkered down in the winter and weren’t killed off by any long, harsh string of sub-zero days. But long-range forecasts aside, there is a pretty constant rule when it comes to the bloodsucking insects.
“The more water, the more mosquitoes there are generally,” said Hogeveen. Water is something Southwestern Ontario got plenty of this winter and spring. February was the perfect storm for flooding, the worst Southwestern Ontario has seen in more than 40 years. Unseasonably warm temperatures broke records for two days straight, melting the snow pack and sending rivers over their banks — all while the region was pummelled by a month’s worth of rain in just 48 hours.
Two months later, freezing rain coated branches and hydro wires during a rare late April ice storm, downing trees and knocking out power to hundreds of thousands across the province. Before the warm-up at the end of the month, April was on track to be one of the coolest on record. The chilly temperatures aren’t exactly bad news when it comes to mosquitoes, said Hogeveen.
“If we have warm, hot temperatures with no rain, we’ll have fewer mosquitoes, but more likely more West Nile virus activity,” he said. “It’s the temperatures that actually have a varying degree of influence on the virus.”
West Nile isn’t the only vectorborne disease the health unit is on the lookout for.
This summer, Hogeveen will be watching for adult aedes aegypti mosquitoes, the species known to transmit the Zika virus which is linked to birth defects.
One of the tropical bugs was captured in a trap in Windsor last August, the first sighting of the species in Canada. It tested negative for the virus.
With outdoor weather upon us, Hogeveen wants the public not to become unwitting mosquito traps themselves.
“We always recommend personal protection, especially this time of year,” he said, adding people should wear light colours, use bug spray and get rid of standing water.