CHICAGO (CBS) — After one of the worst West Nile virus seasons since 2002, the cooler weather is expected to reduce new cases to a trickle, health officials said.

“We are winding down,” said Melaney Arnold, an Illinois Department of Public Health spokeswoman, on Friday. “We may continue to see a few cases because there is a lag time from when a person is bitten to when they start exhibiting symptoms.”

So far this year, Public Health has logged 179 human cases of the disease, including seven deaths — Chicago Fire Department Lt. Thomas Flahive’s Thursday being the latest.

In 2011, there were 34 cases in the state, including three deaths, Arnold said. This year’s hot, dry summer is being blamed for the spike in cases, both in Illinois and nationally. A total of 3,969 cases of West Nile have been diagnosed nationally this year, with 163 deaths, according to the Centers for Disease Control. That’s the worst U.S. outbreak since 2003.

The season’s first hard frost usually signals the end of the West Nile season, Arnold said.

The disease can be difficult to recognize without a doctor’s exam, because the initial symptoms are typically flu-like — fever, nausea, muscle ache and headaches.

The disease can be fatal, particularly among the very old and young and those with compromised immune systems, Arnold said. The best protection while outdoors includes wearing shoes, socks, long pants and a long-sleeved shirt. Insect repellent containing DEET is also advised, health experts says.

(Source: Sun-Times Media Wire © Chicago Sun-Times 2012. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)

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