Press Release  State health officials announce season’s sixth human case of West Nile virus in Massachusetts 

Boston — The Massachusetts Department of Public Health (DPH) today announced the sixth human case of West Nile virus (WNV) in Massachusetts this year, in a man in his 70s who was most likely exposed in a part of Suffolk County outside of Boston. As a result of this additional case, risk levels have been elevated to high in Chelsea, Malden, Revere, and Winthrop.

“As we go into the holiday weekend, it is easy to think of backyards, barbeques, and fun. I also want people to think about mosquitoes,” said Public Health Commissioner Robbie Goldstein, MD, PhD. “This is the time of year when people get exposed to the West Nile virus and Eastern Equine Encephalitis. When you are outside, remember to use mosquito repellent, wear clothing to reduce exposed skin, and empty anything that may be collecting water outside your home to reduce your risk of mosquito bites.”

The first WNV-positive mosquitoes in the state this season were announced on June 16. So far, there have been 273 WNV-positive mosquito samples detected this year from Barnstable, Berkshire, Bristol, Dukes, Essex, Franklin, Hampden, Hampshire, Middlesex, Norfolk, Plymouth, Suffolk, and Worcester counties. Eastern equine encephalitis (EEE) has been detected in 13 mosquito samples. No human or animal cases of EEE infection have been reported so far this year.

The risk for WNV is now high in 11 municipalities: Boston, Brookline, Cambridge, Everett, Newton, Somerville, and Watertown, and moderate in 250 cities and towns in Barnstable, Berkshire, Bristol, Essex, Franklin, Hampden, Hampshire, Middlesex, Norfolk, Plymouth, Suffolk, and Worcester counties.

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 an EPA-registered ingredient (DEET (N,N-Diethyl-m-toluamide), permethrin, picaridin (KBR 3023), oil of lemon eucalyptus (p-menthane-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 percent 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 mosquitoes. Consider rescheduling outdoor activities that occur during the evening or early morning in areas of high risk.

Clothing can help reduce mosquito bites. Wearing long sleeves, long pants, and socks when outdoors will help keep mosquitoes away from your skin.

Mosquito-proof your home

Drain standing water. Mosquitoes lay their eggs in standing water. Limit the number of places around your home for mosquitoes 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 mosquitoes outside by having tightly fitting screens on all 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 mosquitoes near paddock areas. Horse owners should keep horses in indoor stalls at night to reduce their risk of exposure to mosquitoes. 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 suspected of having WNV or EEE, owners are required to report to the Department of Agricultural Resources, Division of Animal Health by calling 617-626-1795, and to the Department of Public Health by calling 617-983-6800.

More information, including all WNV and EEE positive results, can be found on the Arbovirus Surveillance Information web page, which is updated daily, or by calling the DPH Division of Epidemiology at 617-983-6800.

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