Definition of West Nile virus
West Nile virus is a disease spread by mosquitos. The condition ranges from mild to severe.
Causes, incidence, and risk factors
West Nile virus was first identified in 1937 in Uganda in eastern Africa. It was first discovered in the United States in the summer of 1999 in New York. Since then, the virus has spread throughout the United States.
Mild disease, generally called West Nile fever, may cause some or all of the following symptoms:
Signs and tests
Signs of West Nile virus infection are similar to those of other viral infections. There may be no specific findings on a physical examination. However, up to half of patients with West Nile virus infection may have a .
Because this illness is not caused by bacteria, antibiotics do not help treat West Nile virus infection. Standard hospital care may help decrease the risk of complications in severe illness.
In general, the outcome of a mild West Nile virus infection is excellent.
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc. – 9/15/2010