West Nile Fever
West Nile Fever is a viral illness of birds that is carried by mosquitoes. It can cause illness in humans, including encephalitis and viral meningitis. These are illness associated with inflammation of the brain and surrounding tissues. Although West Nile Fever can be fatal, it usually causes a mild illness characterized by headache, fever, and muscle aches. Recovery is spontaneous. It is not spread person to person.
The virus was probably introduced to the United States in 1999 in the vicinity of New York City. It has subsequently been reported over most of the United States. The illness was first discovered in Africa in the 1930's and is present in Europe and the Middle East. Highly fatal to many species of birds, it is an accidental infection of people, spread by mosquitoes that have probably fed upon infected birds. The infection spreads from state to state as birds migrate. There were 3,000 human cases reported in Illinois in 2005, including 119 deaths. Deaths have principally occurred in persons over the age of 50.
West Nile Fever is not easily distinguished from other serious forms of meningitis by symptoms or physical examination. Tests on spinal fluid, obtained by doing a needle tap of the spinal canal, are necessary to establish an accurate diagnosis. This test is done in emergency rooms and in hospitals.
There is no specific treatment for West Nile Fever. It is generally treated with analgesics to help with headache, fever, and muscle aches. Patients with serious headache and fever are often admitted to the hospital. Once a diagnosis of West Nile Fever is established, there is no concern of person to person spread of disease.
To reduce the risk of contracting West Nile Fever and all other mosquito-borne illnesses, take measures to reduce mosquito bites. Primary prevention is to eliminate or treat locations with stagnant water. These are areas where mosquitoes breed and where mosquito larvae are unlikely to be eaten by fish: old tires, buckets, cans, and wheelbarrows, puddles. Use insect repellents and minimize bare skin exposure, especially in the early morning and evening hours when mosquitoes feed. Insect repellants can reduce the number of mosquito bites. Mosquito netting around bedding and in tents can reduce bites in campers.
The West Nile virus can also affect other mammals besides humans, particularly horses. Although a vaccine has been released for prevention of disease in horses, there is no human vaccine available.
Additional information on West Nile Virus and the illness that it causes can be obtained by visiting the following web sites:
- Centers for Disease Control: http://www.cdc.gov/ncidod/dvbid/westnile/index.htm
- Illinois Department of Public Health: http://www.idph.state.il.us/envhealth/wnv.htm