Illinois Department of Public Health reported three new human cases of West Nile Virus this week, bringing the total number of cases in the American state this year to 14. In addition, 8 new counties are now reporting bird or mosquito samples of the virus.

The three new human cases include two men from Cook County who became ill in mid August, one in his 50s and one in his 70s. The other case is of a Woodford County man in his 60s who became ill at the beginning of August.

Director of Illinois Public Health Department, Dr. Eric E. Whitaker said that people need to protect themselves against the common house mosquito because it carries the West Nile Virus (WNV), even though the mosquitoes that have arrived with the recent floods in northeastern Illinois mostly do not.

“West Nile virus can cause illness, from mild to severe, and even death in some cases, so people need to remember to wear insect repellent with DEET and protect themselves when outdoors,” said Whitaker in a statement from Springfield yesterday, 29th August.

So far this year, 25 counties in Illinois have reported positive tested cases of WNV infection in humans or bird or mosquito samples.

The first human case in Illinois this year was reported from DuPage County in mid June, the same county that reported the state’s first positive mosquito sample at the end of May 2006. The first human case reported last year was in St Clair County in early August.

Last year 77 of the 102 counties in the state of Illinois reported positive tested cases of WNV in humans, mosquitoes, birds and horses. The total number of human infections reported last year was 215 including 10 people who died.

Infected birds pass WNV onto mosquitoes when they feed on them.

About 8 in 10 people infected with WNV have no symptoms, but one or two out of 10 usually start feeling ill between 3 and 14 days after being bitten by a WNV carrying mosquito.

The symptoms are usually mild and include fever, headache and body aches, rather like having the flu.

In rare cases the disease can be fatal because it can develop into encephalitis and meningitis. People over 50 years old are at highest risk of the more severe illness.

To avoid being bitten by a mosquito carrying WNV, don’t go outdoors during dusk and dawn because this is when they tend to fly around. Also, keep them out of your house as much as you can by keeping screens on windows and doors securely fastened and make sure they have no rips or tears. Keep doors and windows shut at night, and during the day as much as possible.

The Illinois Public Health Department also recommends that you wear socks and shoes, long pants and long sleeved shirts or blouses when outdoors and apply an insect repellent that containes DEET, picardin or oil of lemon eucalyptus. Always read the instructions on the label and don’t apply on infants before speaking to a doctor first.

Mosquitoes breed in water that has been standing a few days. Eliminate any pools around your garden or back yard including water that has collected in flower pots, roof gutters, old tires, any kind of container. Change bird bath water every week, keep fish in ornamental ponds (they eat the mosquito larvae) and maintain wading pools correctly. Cover rain barrels with 16 mesh wire (this is too small for the insects to get through).

Report areas of stagnant water such as roadside ditches and flooded yards to your local municipal government if it has a mosquito control program.

WNV surveillance includes laboratory testing of mosquitoes and dead wild birds including crows, blue jays, robins and other perching birds (a WNV infected house finch was reported in County Woodford this year on 17th August). Sick horses and humans are also tested if they develop WNV symptoms.

The Illinois Health Department said anyone who sees a sick or dying bird such as a crow, blue jay, robin or other perching bird should contact their local health department who will decide if it should be collected for testing.

West Nile Virus first appeared in the United States in New York in 1999 and in dead birds in Illinois in 2001. The following year the state saw its first human infections and deaths.

By the end of that year (2002), Illinois had reported more human cases (884) and deaths (67) than any other state in the US. After that the epicentre moved elsewhere, but the state still sees human cases in the 200 plus region and deaths in the 10 plus region (in 2005 there were 252 cases and 12 deaths, in 2006 there were 215 cases and 10 deaths reported in Illinois, the sixth highest in the US).

Click here for the WNV section of Illinois Public Health Department, including weekly updates.

Written by: Catharine Paddock