West Nile Virus

The Twin Cities' Source for Local Information About West Nile Virus

Introduction

What is West Nile Virus?

How is it Transmitted?

How is it Measured in the Environment?

How is it Measured and Tracked?

Laboratory Evaluation

Molecular Actions of the Virus

Symptoms and Target Organs

What's New for Health Professionals?

What is West Nile Virus?


West Nile Virus (WNV) is a flavivirus commonly found in Africa, West Asia and the Middle East. The disease is characterized by flu-like symptoms, typically lasting only a few days without any long-term effects. In a small number of cases this infection can proceed to a more serious infection of the brain, spinal cord and surrounding membranes called West Nile Encephalitis (see below).

It can take from 3 to 14 days to show symptoms of the disease, once the virus is in the body. You may not even realize you have the virus, because the symptoms are usually mild, and look like the flu. The more severe form of the disease may last several weeks, and the neurological effects may be permanent.

West Nile Virus (WNV) is a flavivirus commonly found in Africa, West Asia and the Middle East. The disease is characterized by flu-like symptoms, typically lasting only a few days without any long-term effects. In a small number of cases this infection can proceed to a more serious infection of the brain, spinal cord and surrounding membranes called West Nile Encephalitis (see below).
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Where did it come from?

West Nile Virus (WNV) is a virus commonly found in Africa. It was identified in Uganda in 1937, in Egypt in the 1950s and in Egypt and France in the 1960s

When did it get to North America?

The first case of WNV encephalitis found in North America was in New York City in the summer of 1999. Since 1999, West Nile Virus has been isolated in mosquitoes, birds, horses andor people in 43 states, and has accounted for 1963 confirmed cases and 94 deaths this year alone.

It remains unknown how the virus came to North America, it could be an infected human, a mosquito transported across the Atlantic Ocean, or a bird migration pattern change.

Click here for a link to the CDC website and current case counts for 2002.

Is West Nile Virus in the Twin Cities?

Yes, there have been both confirmed and probable cases of WNV in the Twin Cities metro area. Click here for maps describing positive cases in people, birds and horses in Minnesota.

If I get the virus, can it make me really ill?

It can take from 3 to 14 days to show symptoms of the disease, once the virus is in the body. You may not even realize you have the virus, because the symptoms are usually mild, and look like the flu. The more severe form of the disease may last several weeks, and the neurological effects may be permanent.

Most people who are infected with WNV do not develop any illness. The estimates are that about 20% of those infected with the virus will develop West Nile Fever. The symptoms are: fever, headache, body aches and sometimes a skin rash and swollen lymph glands.

Sometimes the virus progresses to a more serious disease called West Nile Encephalitis. Encephalitis is an inflammation of the membrane around the brain and spinal cord. The symptoms of this severe form of the disease are: headache, high fever, stiff neck disorientation and muscle weakness progressing to convulsions, coma and paralysis. Fewer than 1 in 150 people who get the virus will develop into the most severe form of West Nile Encephalitis.

Has anyone in the Twin Cities gotten the severe form of the disease?

Yes, there are cases in the Twin Cities: 17 cases of WN fever, 15 cases of meningitis or encephalitis, and 2 cases of flaccid paralysis. There have been no deaths to date.

What should I do if I think I have symptoms of West Nile Virus infections?

Contact your healthcare provider if you have concerns about whether you might have this infection. If you or anyone in your family develops the symptoms of the severe form of this infection, see your doctor immediately..


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