West Nile Virus

What is West Nile Virus?

West Nile virus is a disease that is spread by mosquitoes. Mosquitos get West Nile virus when they feed on birds that are already infected with the virus. Mosquitos then spread the disease to humans and animals when they bite. West Nile virus cannot be spread from person to person or by coming in contact with pets or animals that have the virus.

Only a small percentage of mosquitos carry West Nile Virus and most people who are infected don’t experience any signs or symptoms. In less than 1 percent of cases, the virus can cause serious complications such as encephalitis, an inflammation of the brain that can cause brain damage.

There is no specific treatment for West Nile virus, just supportive care such as rest, hydration and medications to help the symptoms. Most people infected with West Nile virus recover completely

The best way to prevent infection is to avoid mosquito bites by using repellent and other measures.

West Nile Virus: Reviewed by Claire McCarthy, MD
© Boston Children’s Hospital, 2012