West Nile Virus

  • Medical Author:
    John P. Cunha, DO, FACOEP

    John P. Cunha, DO, is a U.S. board-certified Emergency Medicine Physician. Dr. Cunha's educational background includes a BS in Biology from Rutgers, the State University of New Jersey, and a DO from the Kansas City University of Medicine and Biosciences in Kansas City, MO. He completed residency training in Emergency Medicine at Newark Beth Israel Medical Center in Newark, New Jersey.

  • Medical Editor: Melissa Conrad Stöppler, MD
    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

Quick GuideWest Nile Virus: Causes, Symptoms, and Treatment

West Nile Virus: Causes, Symptoms, and Treatment

Is the West Nile virus contagious?

The West Nile virus is not contagious. It cannot be transmitted from person to person. A person cannot get the virus, for example, from touching or kissing a person who has the disease or from a health-care worker who has treated someone with the disease.

Humans are called a "dead-end" host for the virus, meaning one that can be infected but whose immune system usually prevents the virus from multiplying enough to be passed back to mosquitoes and then spread to other hosts.

There also is no evidence that a person can get the virus from handling live or dead infected birds. However, avoiding skin contact when handling dead animals, including dead birds, is recommended. Gloves or double plastic bags should be used to remove and dispose of carcasses.

Besides mosquitoes, can other insects transmit the West Nile virus?

Infected mosquitoes are the primary method of transmission of the West Nile virus and were the source of the 1999 New York outbreak.

Ticks infected with the West Nile virus have been found in Asia and Africa. Their role in the transmission and maintenance of the virus is uncertain. However, ticks have not been associated in the transmission of the West Nile virus in the New York outbreak.

Are there other viruses like the West Nile virus?

The West Nile virus is closely related to the Japanese encephalitis virus and the St. Louis encephalitis virus, which are found in the southeastern and midwestern United States. These viruses are also mosquito-borne and have a similar life cycle in birds and mosquitoes and occasionally strike people.

A major difference is that St. Louis encephalitis is "silent" in birds, generally not killing them, so there is usually no warning before a human case occurs. With the West Nile virus (at least the American strain), birds, particularly crows, become ill or die and therefore offer an early warning system.

Medically Reviewed by a Doctor on 11/20/2015

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