More Mosquitoes Doesn't Mean Higher West Nile Risk

MINNEAPOLIS (WCCO) -- It's getting to be the time of year when you need to have the bug spray handy. Mid-July through September are typically the worst months for mosquitoes.

It's also the time when there's an increased risk for West Nile virus. The illness is spread through mosquitoes and can be deadly.

How the weather plays out in the next few weeks could determine the threat for West Nile. While a lot of rain and humidity are conditions that will increase the number of mosquitoes, that doesn't necessarily increase the risk of contracting West Nile.

This year's mosquito population is growing because of a rainy, humid July. Mosquito Control may set a new record in terms of acres treated for that pesky bug.

"We're just having wave after wave of rainfall and mosquitoes are triggered by rainfall events," said Mike McLean with Mosquito Control.

The same can't be said for potential Weet Nile virus cases. That also depends on weather.

"West Nile virus, ironically, does the best when things are dry and hot for a long period of time," McLean said.

Dry weather keeps new mosquitoes from hatching, reducing the population. But it causes many people to let their guard down and go into the woods without bug repellent.

"It doesn't even have to do with how annoying mosquitoes are, it has to do with how old the population is," McLean said.

For Harold Lake who's visiting Afton State Park, he isn't thinking about West Nile but just the overall nuisance of a bug that bites.

"Keep the mosquitoes away. What can ya say, they're attracted to sweat, they're attracted to heat, I guess," said Lake. "Don't want to get bit."

With weeks of summer still ahead, his hope is that he always has a supply of bug spray nearby.

"Spray up, rule of the thumb, spray up," Lake said.

Only certain breeds of mosquitoes carry West Nile. The mosquitoes that hatch after a lot of rain, the floodwater mosquito, does not carry the virus. The Minnesota Department of Health hasn't had any reports this year of West Nile in humans. There is one report of West Nile virus in a crow.