Untold numbers of floodwater mosquitoes should soon start climbing out of their watery cribs, shaking off their childhood torpor and dive-bombing for blood meals wherever they can find them.
Nurtured by the May rains that flooded rivers and basements across the region, generations of eggs hatched en masse last week. The larvae and pupae are now awaiting a spell of warmer weather to mature and begin buzzing about.
“My guess is we should see noticeable biting, if the temperatures rise, by the end of this week,” said Mike Szyska, director of the Northwest Mosquito Abatement District in Wheeling.
“We are definitely going to have a floodwater mosquito problem unlike any we’ve had in years–soon,” he said.
What Illinois’ drenched May means for the state’s West Nile virus outlook this summer isn’t clear, but the prospects are disconcerting.
Floodwater mosquitoes–small, nasty biters–are not thought to be the main culprit in transmitting the virus from birds to people.
But if temperatures rise and puddles shrink, conditions could become prime for the culex mosquitoes that are thought to be the top transmitters of West Nile in the state.
Epidemiologists are uncertain what course West Nile virus will take in Illinois this summer, the third year the illness has been a threat. The first year saw 66 deaths from the virus in Illinois. Last year, one person died.
Although researchers can’t predict whether the disease will hit humans hard again this year, the rains make it likely that the mosquitoes will be plentiful.
“We’ve got potential breeding grounds all over. What we have to watch is the temperature. The warmer conditions are, the faster mosquitoes will breed, the more generations there’ll be, and the more of a problem we’ll have,” said Richard Lampman, an entomologist with the Illinois Natural History Survey.
Previous years’ weather patterns suggest a moister-than-average May will be followed by a drier-than-average summer with fewer days hotter than 90 degrees, said WGN-TV meteorologist Tom Skilling. WGN is owned by Tribune Co., which also owns the Chicago Tribune.
The double-barreled mosquito threat–from floodwater and culex mosquitoes–alarms pest-control professionals. Worried by pools of standing water throughout the Chicago area, organizations are spraying larvicides and trying to prevent the bugs from emerging as ravenous adults.
Resources are stretched tight, summer hasn’t started yet, and the peak of the West Nile virus season is still at least six weeks away.
“It’s very expensive, because you have so many acres to treat,” said Linn Haramis, an entomologist with the Illinois Department of Public Health.
Although mosquitoes are proliferating in the area, none has tested positive for West Nile virus in more than 50 tests, officials said.
Chicago authorities do not think recent flooding will worsen the West Nile risk, but they called on property owners Tuesday to empty standing water around their homes and properties.
The city can ticket and charge owners of building sites who don’t remove standing water.
People should call 311 if they spot dead blue jays or crows so the birds can be tested for the virus, officials said. The city will spend $238,000 on surveillance and $855,000 to spread larvicide in 210,000 sewer catch basins.
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Edited by Patrick Olsen (polsen@tribune.com) and alBerto Trevino (atrevino@tribune.com)
