Press Release  State health officials announce second EEE human case and a second horse case in Massachusetts

Boston — The Massachusetts Department of Public Health (DPH) today announced a second confirmed case of Eastern equine encephalitis (EEE) in a human and a second confirmed case in a horse this year. The human case is a woman in her 30s. Both were exposed in the area of Plymouth County that was aerial sprayed Tuesday night and both became infected before spraying was done this week.

There are no risk level changes associated with these findings.

There have been 76 EEE-positive mosquito samples so far this year detected from Abington, Carver, Halifax, Kingston, Marion, Middleborough, Plymouth, Rochester, Wareham, and Whitman in Plymouth County; Bedford, Raynham, Taunton, and Westport in Bristol County; Barnstable in Barnstable County; Dedham and Medfield in Norfolk County; Sudbury in Middlesex County; Amesbury and Haverhill in Essex County; and Dudley and Upton in Worcester County.

The season’s first EEE-positive mosquitoes in Massachusetts were announced on July 3rd from Carver. Since then, there have also been EEE-infected mosquitoes identified in Abington, Halifax, Kingston, Marion, Middleborough, Plymouth, Rochester, Wareham, and Whitman in Plymouth County; Bedford, Raynham, Taunton, and Westport in Bristol County; Barnstable in Barnstable County; Dedham and Medfield in Norfolk County; Sudbury in Middlesex County; Amesbury and Haverhill in Essex County; and Dudley and Upton in Worcester County.

“This evidence of the spread of EEE to a person and a horse in Plymouth County before aerial spraying confirms risk in the area,” said Public Health Commissioner Robbie Goldstein, MD, PhD. “We expect that the aerial spraying will help prevent risk for EEE from continuing to escalate in the area, but it does not eliminate it completely. We are asking people to be consistent about taking steps to prevent mosquito bites.”

EEE is a rare but serious and potentially fatal disease that can affect people of all ages. EEE is generally spread to humans through the bite of an infected mosquito. The first human infection with EEE virus this year was a male in his 80s exposed in southern Worcester County.

“EEE risk does not end on Labor Day,” said State Epidemiologist Dr. Catherine M. Brown. “People should continue to use a mosquito repellent with an EPA-registered active ingredient any time they are outdoors. As the weather gets cooler it will be easier to wear long sleeves and pants to reduce exposed skin. We continue to strongly advise that individuals in areas where EEE risk is at high and critical levels reschedule evening outdoor events to avoid peak mosquito biting hours.”

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, such as DEET (N,N-diethyl-m-toluamide), permethrin, picaridin (KBR 3023), or 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 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 draining or discarding items that hold water. Check rain gutters and drains. Empty 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 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 West Nile virus (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 at Mosquito-borne Diseases | Mass.gov, which is updated daily, or by calling the DPH Division of Epidemiology at 617-983-6800. 

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