Signs and Symptoms of West Nile Virus: An Overview
When a person becomes infected with the
West Nile virus, symptoms can vary. Some people will have no symptoms, others may develop flu-like symptoms, and some develop serious symptoms.
No Symptoms
Approximately 80 percent of people who are infected with West Nile virus will not show any symptoms at all.
Mild Symptoms
Up to 20 percent of the people who become infected with West Nile virus have mild symptoms that can include:
- Fever
- Headache
- Body aches
- Nausea
- Vomiting
- Swollen lymph glands
- Skin rash on the chest, stomach, and/or back.
These symptoms can last from a few days to several weeks. These mild symptoms are sometimes called West Nile fever.
Serious Symptoms
About 1 in 150 people infected with West Nile virus will develop severe symptoms. Symptoms of severe disease (also called neuroinvasive disease, such as
West Nile encephalitis,
meningitis, or West Nile poliomyelitis) can include:
- High fever
- Headache
- Neck stiffness
- Stupor
- Disorientation
- Coma
- Tremors
- Convulsions
- Muscle weakness
- Vision loss
- Numbness
- Paralysis.
These severe West Nile virus symptoms may last for several weeks, but neurological effects may be permanent. Neurological effects can include:
- Hearing and/or speech loss
- Blindness
- Permanent brain and/or nerve damage
- Behavioral changes
- Cognitive disabilities
- Lack of muscle control
- Seizures
- Memory loss.