Signs and Symptoms
About 80% of those infected with West Nile Virus will have no symptoms. About 20% will experience mild to moderate flu-like symptoms such as:
- Fever
- Nausea, vomiting
- Headaches
- Body aches
- Skin rashes
- Swollen lymph nodes
These symptoms typically last for only a few days and have no long-term health impact.
Less than 1% (about 1 in 150) of those infected will develop more serious disease, in which there is brain involvement. This can lead to life-threatening encephalitis and/or meningitis. Symptoms of encephalitis include:
- High fever
- Extreme muscle weakness
- Neck stiffness
- Stupor, disorientation
- Tremors, convulsions
- Coma
- Paralysis (rarely)
The fatality rate of those with the more serious form of the disease ranges from 3-15% and is highest among the elderly. Individuals with compromised immune systems also have an increased risk of severe disease.
