Skip to content.
HomeE-ServicesCity GovernmentLiving & WorkingDoing Business
You Are Here: Home > E-Services > FAQs

West Nile Virus

Related Pages: Office of the City Manager » Public Health

The following FAQs are provided by the Public Health Division. For a more detailed and complete listing, please read the Massachusetts Department of Public Health's West Nile Virus Fact Sheet (162KB).

What is West Nile Virus (WNV)?

West Nile virus is a mosquito-carried virus that usually causes mild or no illness in humans. In rare cases, WNV can cause encephalitis (swelling of the brain) or meningitis (swelling of the lining of the brain and spinal cord).

How is WNV spread?

WNV is most commonly spread to people by the bite of an infected mosquito. A mosquito can become infected by biting a bird that carries the virus. It may also be spread through blood transfusions or organ transplants. There are reports that WNV may be passed from pregnant or breastfeeding women to their babies. The risk to the unborn baby is still unknown.

What are the symptoms?
  • No symptoms in most people. Approximately 80% 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% 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. 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. persons aged 50 and older have a higher risk of developing severe illness.
Is there treatment or a vaccine for WNV?

There is no human vaccine or specific treatment of WNV infection, but heath care providers can treat the symptoms of WNV. In severe cases, hospitalization may be needed to provide supportive care.

How can I protect myself from WNV?

Since WNV is commonly spread by mosquitoes, the following list includes things you can do to reduce the chances of being bitten:

  • Limit outdoor events between dusk and dawn when mosquitoes are most active.
  • If you must be outdoors during this time, wear long pants, a long-sleeved shirt and socks, even if the weather is hot.
  • Use an insect repellent with DEET, permethrin, picaridin, or oil of lemon eucalyptus. Be sure to follow all instructions and warnings on the label, especially if using these products on children.
  • Ensure all windows and door screens are tightly attached and free of any holes. Repair any holes that may be present to keep mosquitoes out of your home.
  • Remove any standing, stagnant water around your home. Here are some important tips:
    • If recycling containers are left outdoors, drill a hole in the bottom to drain any water that may collect inside.
    • Remove leaves and debris that my clog rain gutters.
    • Water in birdbaths should be changed every few days.
    • Properly chlorinate and clean swimming pools.
© 2017 | Copyright City of Worcester, MA | All Rights Reserved. | Login | Disclaimer | Site Map