Symptoms of West Nile Virus

West Nile Virus Update

A truck spraying pesticides to control mosquitoes.
It is important to control mosquitoes to stop the spread of West Nile virus infections. Justin Sullivan/Getty Images

Although children are thought to be at low risk from the West Nile Virus, it is important to know the symptoms if your child gets sick and has recently had a mosquito bite. Remember that many of the symptoms of the West Nile Virus are shared by many of the more common and less serious viral infections that can infect children.

Symptoms of West Nile Virus

It will likely come as a surprise to many people that up to 80% of West Nile virus infections are asymptomatic - they cause no symptoms at all.

Only about 20 percent of people who become infected with West Nile virus will develop West Nile virus symptoms, which can include:

These symptoms are usually mild and might last a few days or a few weeks, although some people may remain fatigued for several months.

More rarely, people who get infected with West Nile virus can have more severe disease neuroinvasive disease, such as West Nile encephalitis or meningitis, with severe symptoms that can include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, seizures, muscle weakness, vision loss, numbness and paralysis. Although neuroinvasive disease can occur in people of any age, people over age 50 and people with immune system problems are at the highest risk.

What To Know About West Nile Virus Infections

Other things to know about West Nile virus infections include that:

  • The incubation period for West Nile disease is usually about 2 to 14 days. That's the time from when you are bitten by an infected mosquito to when you might develop West Nile virus disease symptoms.
  • There is no specific vaccine, treatment, or cure for West Nile virus infections.
  • In general, experts do not recommend routine testing for West Nile virus, even if you have mild symptoms. Testing is usually reserved for those with more severe symptoms.
  • West Nile virus is not contagious and can't be spread through casual contact with other people.
  • West Nile virus season typically peaks in mid-August and continues though October.

And be sure to take precautions to protect your kids from the West Nile virus, including that they use insect repellent, wear protective clothing and that you empty standing water around your home so that mosquitoes can't breed easily.


CDC. West Nile Virus Clinical Evaluation & Disease. Accessed May 2016.

Ferguson et al. Characteristics of the Rash Associated with West Nile Virus Fever. Clinical Infectious Diseases. Volume 41, Issue 8. pp. 1204-1207.

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