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Click here to see the USGS map of all reported West Nile Virus cases this year.

West Nile Virus
According to the CDC (Centers for Disease Control and Prevention) West Nile virus (WNV) is a potentially serious illness. Experts believe WNV is established as a seasonal disease in North America that flares up in the summer and continues into the fall.

Between 2000 and 2006, 54 people were reported with WNV infection in Massachusetts. Six of these people died. Click here to see the Mass. Dept. of Public Health fact sheet with more information about WNV.

Click here to learn more about your chances for serious illness or death in Massachusetts.

No Symptoms in Most People.
Approximately 80 percent of people (about 4 out of 5) who are infected with WNV will not show any symptoms at all.

Milder Symptoms in Some People.
Up to 20 percent of the people who become infected have symptoms such as fever, headache, and body aches, nausea, vomiting, and sometimes swollen lymph glands or a skin rash on the chest, stomach and back. Symptoms can last for as short as a few days, though even healthy people have become sick for several weeks.

Serious Symptoms in a Few People.
About one in 150 people infected with WNV will develop severe illness. The severe symptoms can include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis. These symptoms may last several weeks, and neurological effects may be permanent.

How is West Nile Virus Spread?
Most often, WNV is spread by the bite of an infected mosquito. Mosquitoes become infected when they feed on infected birds. Infected mosquitoes can then spread WNV to humans and other animals when they bite.

Not all mosquitoes carry West Nile Virus, and even then it only appears at certain times of the year.  The Mass. Dept. of Public Health carefully monitors mosquito populations throughout the state to determine if there is a risk. 

Check with the Mass. Dept. of Public Health or your local board of health to learn if West Nile Virus has been found in your area.

In a very small number of cases, WNV also has been spread through blood transfusions, organ transplants, breastfeeding and even during pregnancy from mother to baby. WNV is not spread through casual contact such as touching or kissing a person with the virus. For more information on risk factors and treatment click here to check the CDC website.

Prevent mosquito bites!
Click here to learn how you can protect yourself.