West Nile Virus

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West Nile virus is a potentially serious illness transmitted by mosquitoes. It was first discovered in the United States in 1999. Since then, the virus has spread throughout the United States.

Experts believe the West Nile virus is a seasonal epidemic in North America that flares up in the summer and continues into the fall. The risk of disease decreases as the weather becomes colder and mosquitoes die off.

SYMPTOMS:
Most people infected with the West Nile virus have no signs or symptoms but there is no way to know in advance if you will develop an illness or not.

MILD INFECTION SIGNS AND SYMPTOMS:
About 1 in 5 people who are infected will display symptoms which can include: fever, headache, body aches, nausea, fatigue, vomiting, and sometimes skin rash, swollen lymph glands and eye pain.

SERIOUS INFECTION SIGNS AND SYMPTOMS:
The severe symptoms can include: high fever, severe headache, stiff neck, disorientation or confusion, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis.  These symptoms may last several weeks, and neurological effects may be permanent.  If you experience any of these symptoms after being bitten by a mosquito, you should seek medical attention immediately.  People typically develop symptoms between 3 and 14 days after they are bitten by the infected mosquito.

HOW DOES THE WEST NILE VIRUS SPREAD?
Most often the West Nile virus is spread by the bite of an infected mosquito.  Mosquitoes become infected when they feed on infected birds.  Infected mosquitos can then spread the virus to humans and other animals when they bite. The virus is not spread through casual contact such as touching or kissing a person with the virus.

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SOURCE: Centers for Disease Control and Prevention
PREPARED BY: 211/mm
CONTENT LAST REVIEWED: August2023