What Is West Nile Virus?

Typically found in Africa, the Middle East and western Asia, West Nile virus first was detected in  Illinois in 2001, when it was found in crows in the Chicago area. A year later, the virus had spread to 100 of the state’s 102 counties, according to the Kane County Health Department.

The first human case of West Nile virus surfaced in Illinois in August 2002, according to the department’s West Nile virus information page. The Web page notes that by the end of 2002, the state had logged 884 human cases of the virus and 67 deaths — more than any other state in the nation. The numbers dropped dramatically in the following years, with only 54 human cases and one death in 2003, and 60 human cases and four deaths in 2004.

The disease is spread primarily by the Culex family of mosquitoes, which pick up the virus while feeding on an infected bird. The mosquito then transmits the illness afterward when it bites again.

The Kane County Health Department says that most people exposed to West Nile show no symptoms. Some, however, may become ill within three to 14 days of exposure. Only about two people in 10 who are bitten by an infected mosquito will experience any illness.

West Nile virus occurs primarily in the late summer or early fall, although the peak season is usually April-October.

West Nile illness is usually mild, with symptoms that include fever, headache and body aches, the Health Department says. Skin rash and swollen lymph glands also may be seen in mild cases.

But serious illness — people older than 50 years have the greatest risk of severe disease — such as encephalitis and meningitis can be a part of West Nile disease, and death is possible. Those with more severe infections may develop a high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, occasional convulsions and paralysis. If you have any of these symptoms, the Health Department urges you to contact your doctor.

While those older than 50 have the highest risk of severe illness from West Nile virus, people with compromised immune systems are as well.

Still, the the Health Department says, anyone can get the virus.

The Health Department says there is no specific treatment nor a vaccine for West Nile virus.

Related:

• Friday, July 26, 2013: West Nile virus Threat Grows in Kane County
• Friday, July 26, 2013: Steps You Can Take Against West Nile Virus
• July 16, 2013: State Reports West Nile Activity in Kane County
• July 16, 2013: West Nile Virus Detected in Kane County