A virus is a microscopic organism that causes infection and
disease. Viral illnesses can range from mild to severe, including examples such
as the common cold, West Nile virus, polio, and smallpox.
Author
Maria G. Essig, MS, ELS
Editor
Susan Van Houten, RN, BSN, MBA
Associate Editor
Pat Truman, MATC
Primary Medical Reviewer
Kathleen Romito, MD - Family Medicine
Specialist Medical Reviewer
W. David Colby IV, MSc, MD, FRCPC - Infectious Disease
Last Updated
July 31, 2008
WebMD Medical Reference from Healthwise
Last Updated:
July 31, 2008
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