Most people infected with West Nile Virus will experience no symptoms of the illness. West Nile Virus is a potentially serious illness. People typically develop symptoms between 3 and 14 days after they are bitten by the infected mosquito. While most people infected with the virus will experience no symptoms, some people may have mild symptoms while others may experience more serious effects of the illness.
Mosquito on leaf
Severe Symptoms
Severe symptoms of the illness can include:
  • Coma
  • Convulsions
  • Disorientation
  • Headache
  • High fever
  • Muscle weakness
  • Neck stiffness
  • Numbness
  • Paralysis
  • Stupor
  • Tremors
  • Vision loss
These symptoms may last several weeks, and neurological effects may be permanent.

Mild Symptoms
Milder symptoms can include:
  • Body aches
  • Fever
  • Headache
  • Nausea
  • Skin rash on the chest, stomach and back
  • Swollen lymph glands
  • Vomiting
Symptoms can last for as short as a few days, though even healthy people have been sick for several weeks.

There is no specific treatment for WNV infection. In cases with milder symptoms, people experience symptoms such as fever and aches that pass on their own. In more severe cases, people usually need to go to the hospital where they can receive supportive treatment including intravenous fluids, help with breathing and nursing care.

When to Seek Medical Attention
Milder WNV illness improves on its own, and people do not necessarily need to seek medical attention for this infection though they may choose to do so. If you develop symptoms of severe WNV illness, such as unusually severe headaches or confusion, seek medical attention immediately. Severe WNV illness usually requires hospitalization. Pregnant women and nursing mothers are encouraged to talk to their doctor if they develop symptoms that could be WNV.