West Nile virus is a mosquito-spread infection that usually causes
either no symptoms or mild symptoms of headache, fever, body aches, and
sometimes a rash and swollen lymph nodes. In rare cases, it can lead to
inflammation of the brain (encephalitis) or the tissues surrounding it and the
spinal cord (meningitis).
The virus lives in and multiplies in birds. Mosquitoes become
infected when they bite and draw blood from infected birds. Mosquitoes may then
transmit the virus to humans and animals.
When West Nile virus affects the brain, symptoms may include
headache, high fever, stiff neck, reduced attention to surroundings,
and disorientation. Symptoms may also include tremors, convulsions, muscle weakness or paralysis, and
No specific treatment is available for West Nile virus infection.
Treatment for severe infection involves supportive care in a hospital to help
the body fight the illness on its own. In a few cases the infection is
People usually recover fully from the mild form of West Nile virus
infection. But permanent problems may develop in those who have encephalitis,
especially children and older people. They may have seizures, memory loss,
personality changes, tremors, trouble with walking or balance, or brain
August 10, 2012
E. Gregory Thompson, MD - Internal Medicine & W. David Colby IV, MSc, MD, FRCPC - Infectious Disease
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