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West Nile Cases Down Thanks To Cooler Temps

MINNEAPOLIS (WCCO) -- For those hoping for a hot and sticky August, there may be a silver lining to our below-average temperatures.

The Metropolitan Mosquito Control District says the overall number of mosquitoes are down this summer.

And because of that, we could see fewer cases of West Nile virus and other mosquito-borne diseases.

One of the main symptoms of West Nile virus is a high fever that doesn't go away.

It can be deadly for the elderly and for people who have a pre-existing illness.

The perfect storm for a bad West Nile season is plenty of rainfall during the early summer months, follow by the "dog days" heat August brings.

But the mosquito that carries West Nile, culex tarsalis, can have a down year.

West Nile
Samples of culex tarsalis, the mosquito that transmits the West Nile virus (credit: CBS)

Its Kryptonite is a cooler-than-normal August.

"The numbers of that particular mosquito seem to be way down now," said Mike McLean of the Metropolitan Mosquito Control District. "I think we've had fewer mosquitoes than the past, couple years."

Late August and September are when we see the most West Nile cases.

Last year there were 65 cases in the state, resulting in five deaths.

We have only seen nine cases so far this summer.

"This year we were hoping for this cool stretch in July and August. We got it," McLean said. "Hopefully that will keep the West Nile cases down."

And the immediate forecast not only looks comfortable for the Minnesota State Fair, it looks like it could help take the bite out of the West Nile threat.

Even so, health officials still want people to be on alert. Mosquitoes stay resilient until temperatures really cool down.

"As long as the mosquitoes are active, West Nile virus can be transmitted. It's really that simple," McLean said. "We really aren't out of the woods until we get that first, hard frost."

That means keep using insect repellent when you are outdoors, even if it seems like you don't need it.

Horses are also sensitive to West Nile, so owners will want to keep that in mind this time of year as well.

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