West Nile Virus

• Definition
· West Nile Virus is an Arbovirus which are viruses that are transmitted from blood-sucking insects such as mosquitos.

• Overview
· West Nile Virus was first identified in the West Nile area of Uganda in 1937 where it was found primarily in wild birds.
· West Nile Virus is usually transmitted from birds to humans through infected mosquitos.
· West Nile Virus can be transmitted by infected organ transplants and blood products.
· West Nile Virus infection was first identified in the United States in New York City in 1999. Since then there has been 8,900 reported cases occurring in every state of the union.

• Symptoms
· West Nile Virus incubation period is between 2 and 14 days.
· West Nile Virus symptoms of infection include:
· fever
· fatigue
· headache
· muscle weakness
· rash (red indurated rash on the trunk)
· nausea and vomiting
· swollen lymph nodes

• Complications
· West Nile Virus will infect the brain in about 1% of cases and cause a meningitis or encephalitis (swelling of the brain) and is more common in the elderly and diabetics
· West Nile Virus infection is fatal in 10 % of cases.

• Treatment
· There is no vaccine available for West Nile Virus.
· There is not cure for the infection and infected people should seek medical attention for supportive care.

• References
Huhn GD et al: West Nile virus in the United States: an update on an emerging infectious disease. Am Fam Physician 2003;68:653. [PMID: 12952382]

Posted on September 24, 2008

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