West Nile Disease Symptoms

West Nile disease, or West Nile virus, is an illness transmitted by infected mosquitoes. About 80 percent of people who become infected with the virus will not experience any symptoms, according to the U.S. Centers for Disease Control and Prevention. About 20 percent will experience mild symptoms, but about 1 in 150 people infected will experience serious symptoms that may even result in death. West Nile virus is common in Africa, Asia and the Middle East and was first documented in the United States in 1999. Since that time, the virus has been reported in all 48 continental states. In 2008, 1,356 cases were reported in the United States, including 44 fatalities, according to the CDC.

Mild Symptoms

• People who develop mild symptoms from a West Nile virus infection may experience a fever, muscle and body aches, headaches, nausea and vomiting. Some people may also experience a skin rash or swollen lymph glands. In most cases, symptoms will last only a few days, but in some cases they may persist for a few weeks.

Severe Symptoms

• People who develop a severe illness because of West Nile virus may develop a high fever, severe headaches, muscle weakness and tremors, neck stiffness, numbness and paralysis. Disorientation, stupor, convulsions, vision loss and coma may also result. People who become severely ill will typically be sick for several weeks, and neurological effects and impairment may be permanent.

Prevention

• The best way to avoid becoming infected with West Nile virus is to avoid exposure to mosquitoes and eliminate mosquito-breeding areas. You should eliminate standing water such as birdbaths around your home and make sure roof gutters aren't clogged. Also be sure to empty swimming pools that are not in use. If you will be outside at times when mosquitoes tend to be around, such as dusk and dawn, wear long pants and long-sleeved shirts and use a mosquito repellent containing DEET.

Risk Factors

• Because the virus is transmitted by mosquitoes, anyone can become infected with West Nile virus. However, some people are more at risk of developing serious complications from the infection. For example, people who are older than 50 or people who have a weakened immune system, such as those who have undergone an organ transplant, are more likely to become severely ill or die from the virus.

Diagnosis

• If your doctor suspects West Nile virus, a test will be conducted on blood or fluid obtained from the area surrounding the spinal cord. A sample that tests positive for West Nile virus ribonucleic acid or that shows rising levels of West Nile virus antibodies is an indication of the virus.

Treatment

• Most people who develop West Nile virus will recover on their own with no medical treatment. In cases where more serious illnesses such as encephalitis develop as a result of the infection, intravenous fluids and pain-relieving medications may be required. In severe cases, interferon therapy has sometimes been effective in helping patients recover more quickly.