West Nile Virus | Symptoms


What are the symptoms of West Nile virus infection?

Most people who are infected with West Nile virus have no symptoms. Others may have only mild symptoms, which is called West Nile fever. Symptoms include:

  • Skin rash
  • Fever
  • Headache
  • Nausea
  • Vomiting
  • Diarrhea
  • Loss of appetite
  • Swollen lymph nodes (lymph glands)
  • An achy feeling in the back and muscles

Symptoms usually occur 3 to 14 days after a person is bitten by an infected mosquito and last for 3 to 6 days. Symptoms of the more severe illness the West Nile virus include:

  • A sudden high fever (above 102°F)
  • Severe headache
  • Stiff neck
  • Feeling disorientated or confused
  • Tremors or muscle jerks
  • Seizures
  • Coma
  • Weakness or partial paralysis

These symptoms may last for several weeks. Contact your doctor if you have any of these symptoms and have recently been bitten by a mosquito.


West Nile Virus in the United States: An Update on an Emerging Infectious Disease by GD. Huhn, M.D., M.P.H.T.M., JJ Sejvar, M.D., SP Montgomery, D.V.M., M.P.H., and MS Dworkin, M.D., M.P.H.T.M. (American Family Physician August 15, 2003, http://www.aafp.org/afp/20030815/653.html)

Written by familydoctor.org editorial staff

Reviewed/Updated: 04/14
Created: 04/04