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Press Release Department of Public Health and Boston Public Health Commission announce 12th human case of West Nile virus in Massachusetts

Precautions recommended for avoiding mosquito bites
For immediate release:
  • Department of Public Health
  • Boston Public Health Commission

Media Contact for Department of Public Health and Boston Public Health Commission announce 12th human case of West Nile virus in Massachusetts

Ann Scales, Media Relations Director

BOSTON — The Massachusetts Department of Public Health (DPH) and the Boston Public Health Commission (BPHC) today announced the 12th human case of West Nile virus (WNV) in the state this year and the fifth case in Suffolk County, which includes Boston. The most recent case is a man in his 50s from Suffolk County who is currently hospitalized. He became ill on September 11.

"Labor Day is often considered to be the unofficial end of summer," said DPH State Epidemiologist Dr. Catherine Brown. "But it is not the end of the mosquito season. September is still the peak of transmission season and additional cases of WNV infection are likely to occur. Risk from West Nile virus will continue until the first hard frost."

"This patient became ill less than a week ago, indicating that West Nile virus is actively being transmitted from mosquitoes to people," said Dr. Jenifer Jaeger, Director of BPHC’s Infectious Disease Bureau. "That’s why it is important that people in greater Boston and elsewhere continue using insect repellents, covering exposed skin, and moving indoors when mosquitos are biting."

In 2017, there were six human cases of WNV infection identified in Massachusetts.

WNV is usually transmitted to humans through the bite of an infected mosquito. While WNV can infect people of all ages, people over the age of 50 are at higher risk for severe disease. Most people infected with WNV will have no symptoms. When present, WNV symptoms tend to include fever and flu-like illness. In rare cases, more severe illness can occur.

People have an important role to play in protecting themselves and their loved ones from illnesses caused by mosquitoes.

Avoid Mosquito Bites

  • Apply Insect Repellent when Outdoors. Use a repellent with DEET (N, N-diethyl-m-toluamide), permethrin, picaridin (KBR 3023), oil of lemon eucalyptus [p-methane 3, 8-diol (PMD)], or IR3535 according to the instructions on the product label. DEET products should not be used on infants under two months of age and should be used in concentrations of 30% or less on older children. Oil of lemon eucalyptus should not be used on children under three years of age.
  • Be Aware of Peak Mosquito Hours. The hours from dusk to dawn are peak biting times for many mosquitos. Consider rescheduling outdoor activities that occur during evening or early morning.
  • Clothing Can Help Reduce Mosquito Bites. Wear long-sleeves, long pants, and socks when outdoors to help keep mosquitos away from your skin.

Mosquito-Proof Your Home

  • Drain Standing Water. Mosquitos lay their eggs in standing water. Limit the number of places around your home for mosquitos to breed by either draining or discarding items that hold water. Check rain gutters and drains. Empty any unused flowerpots and wading pools, and change the water in birdbaths frequently.
  • Install or Repair Screens. Keep mosquitos outside by having tightly-fitting screens on all of your windows and doors.

Protect Your Animals

Animal owners should reduce potential mosquito breeding sites on their property by eliminating standing water from containers such as buckets, tires, and wading pools — especially after heavy rains. Water troughs provide excellent mosquito breeding habitats and should be flushed out at least once a week during the summer months to reduce mosquitos near paddock areas. Horse owners should keep horses in indoor stalls at night to reduce their risk of exposure to mosquitos. Owners should also speak with their veterinarian about mosquito repellents approved for use in animals and vaccinations to prevent WNV and EEE. If an animal is diagnosed with WNV or EEE, owners are required to report to DAR, Division of Animal Health by calling (617) 626-1795 and to the Department of Public Health (DPH) by calling (617) 983-6800.

For Boston residents, more information on West Nile Virus is available online in multiple languages at or by phone at (617) 534-5611.

For residents throughout the Commonwealth, more information, including all WNV and EEE positive results, can be found on the Arbovirus Surveillance Information web page at or by calling the DPH Epidemiology Program at (617) 983-6800.


Media Contact for Department of Public Health and Boston Public Health Commission announce 12th human case of West Nile virus in Massachusetts

Department of Public Health 

DPH promotes the health and well-being of all residents by ensuring access to high-quality public health and healthcare services, and by focusing on prevention, wellness and health equity in all people.

Boston Public Health Commission

Erin Curran Serino
(617) 534-3127