What is West Nile encephalitis?

"Encephalitis" is an inflammation of the brain and can be caused by viruses and bacteria including viruses transmitted by mosquitoes. West Nile encephalitis is an infection of the brain caused by West Nile virus. It is closely related to St. Louis encephalitis virus found in the United States.

What Is the incubation period in humans (or time from infection to onset of disease symptoms) for West Nile encephalitis?

Usually 5 to 15 days.

What are the symptoms of West Nile encephalitis?

Mild infections have symptoms that include fever, headache, and body aches, often with skin rash and swollen lymph glands. More severe infection may be marked by headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, paralysis, and rarely death. If you believe you have West Nile, seek medical care as soon as possible.

How do people get West Nile encephalitis?

The bite of a mosquito that is infected with West Nile virus is all it takes to transmit the infection. Mosquitoes become infected when they feed on infected birds. After an incubation period of 1 to 2 weeks, infected female mosquitoes can then transmit West Nile virus to humans and animals while biting. The mosquitoes and the bites they cause do not differ from those bites of an uninfected mosquito.

How is West Nile encephalitis treated?

There is NO specific therapy or vaccine for West Nile infection. In more severe cases, intensive supportive therapy is indicated which includes hospitalization.

Who is at risk for getting West Nile encephalitis?

All residents of areas where virus activity had been identified are at risk of getting West Nile encephalitis; persons greater than 50 years of age have the highest risk of severe disease.