Mosquitoes could be source of West Nile Virus through November - IDPH says to continue to use caution when outdoors

Tuesday, September 28, 2004

By Joyce Morrison, Southern IL News Correspondent
Illinois Leader-

SPRINGFIELD -- While health authorities in Thailand are watching closely a growing number of bird flu cases being passed from one person to another, Illinois health department authorities say that precautions against mosquitoes and the spread of West Nile virus should continue throughout the fall.

The calendar may say that summer is over, but mosquitoes carrying West Nile Virus (WNV) are still very active throughout Illinois. The Illinois Department of Public Health reports most of the mosquito-borne infections occur during the months of August and September.

WNV is transmitted through the bite of a mosquito that has picked up the virus by feeding on an infected bird. The IDPH said that most people with the virus have no clinical symptoms of illness, but some may become ill three to 14 days after the bite of an infected mosquito. Only about two persons out of 10 who are bitten by an infected mosquito will experience illness.

"Mosquitoes feed on birds earlier in the season but as the season progresses, they tend to bite humans and horses which have warmer blood," Steve Shireman, Jersey County Public Health’s Environmental director, said this week.

Illinois has suffered one death so far this year attributed to West Nile Virus, a 58 year old DuPage County man who died on September 1.

Two new cases were reported last week in Cook County according to Dr. Eric E. Whitaker, state public health director. With those two cases, 32 WNV cases have been diagnosed in Illinois this year.

Two horses, one alpaca and 202 birds throughout the state were identified with WNV in 2004. 892 mosquito pools tested positive, including one pool found in Jersey County's small rural community of Kane.

Environmental Director Shireman told IllinoisLeader.com, "We have not had any outbreaks from the discovery due to the community clean-up effort and the awareness causing people to take more precautions."

Illinois led the nation with 884 cases and 66 deaths two years ago. The largest number of deaths were reported during the month of September. No deaths were reported prior to August 10 that year, and the last death reported was November 20.

The next year, in 2003, Illinois reported 54 West Nile human cases and the death of one 78 year old Cook County woman who died on September 30.

California leads the nation this year with 443 cases and 14 deaths. Last year, California reported only three instances while Colorado led the nation with 2,947 cases as the mosquito borne disease moved westward.

Although there has been a drastic reduction of cases since 2002, Illinois still leads surrounding states with the number of reported cases of WNV. Eight cases were reported in Wisconsin, three in Indiana, nine in Iowa , seventeen in Missouri, three in Kentucky and Indiana reported six cases, the Center for Disease Control reports.

Mild cases of West Nile infections may bring on a slight fever or headache. More severe infections are marked by a rapid onset of a high fever with head and body aches, disorientation, tremors, convulsions and, in the most severe cases, paralysis or death.

Symptoms occur three to 14 days after the bite of an infected mosquito. Persons at the highest risk for serious illness are those 50 years of age or older according to the Illinois Department of Public Health.

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