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Risk for West Nile Virus in Boston Raised to Moderate

BOSTON – Friday, July 28, 2023—The Boston Public Health Commission (BPHC) is informing residents that the city’s risk level for West Nile Virus (WNV) was raised from low to moderate by the Massachusetts Department of Public Health due to the increased detection of infected mosquitos in neighboring cities and towns. No human cases of WNV have been confirmed in the City of Boston, however, it is likely that we will see people infected by WNV in our communities, and it is possible that some individuals in Boston may be infected without knowing it.  

The risk for WNV in Boston has typically increased during mosquito season and as the summer progresses. BPHC reminds residents that most people infected with WNV do not experience any signs or symptoms of illness. In some cases, people will experience a headache, fever, nausea, vomiting, and body aches which can last for a few days or several weeks. In most cases, individuals with mild symptoms recover on their own. 

“The Boston Public Health Commission works closely with our partners at the State Department of Public Health to monitor mosquito pools and alert residents of the risk of West Nile Virus,” said Dr. Bisola Ojikutu, Commissioner of Public Health and Executive Director of the Boston Public Health Commission. “During this time of the year and into the fall, we encourage residents to protect themselves by using insect repellant and wearing long sleeve clothing when outside from dusk to dawn for prolonged periods of time.” 

The best way to reduce the risk of WNV is by avoiding mosquito bites. BPHC recommends the following strategies: 

  • Avoid spending extended periods of time outdoors from dusk to dawn, when mosquitos are most active. 

  • Wear long clothing and high socks to keep mosquitos away from your skin.  

  • Use EPA-approved insect repellents like DEET, oil of lemon, eucalyptus, picaridin, or IR3535. 

  • Make sure screens in windows and doors fit properly and do not have any holes.  

  • Regularly empty out and clean bird baths, unused flowerpots, and other vessels containing standing water to prevent mosquitos from breeding. Flip over unused kiddie pools and dispose of old tires, which are also known to attract mosquitos for breeding.  

  • Regularly clean out gutters and remove any debris or blockages.  

Although rare, people who are older than 50 years of age are at higher risk of developing serious symptoms, including high fever, severe headache, confusion, lack of coordination, and muscle paralysis or weakness. If you or someone you know is experiencing these symptoms, contact a health care provider immediately.  

More information on WNV and other mosquito-borne illnesses is available on BPHC’s website



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