Health agents on alert after EEE discovery
The discovery last week of mosquitoes infected with Eastern equine encephalitis in Freetown - the first such finding this season - has put health officials in Plymouth and Bristol counties on notice that the virus is once again active in their territory.
The infected mosquito pool was found in an east section of Freetown, near Route 140, the area where a horse contracted the illness last fall and died.
The timing of this season’s opening EEE case is “right in the ballpark’’ of when infected pools begin to appear, said Tom Lyons, spokesman for the state Department of Public Health.
From midsummer until frost kills the mosquitoes in the fall, EEE is active. The department has designated Freetown, Berkley, Acushnet, and New Bedford at “high risk’’ for EEE this year, based on last year’s mosquito activity. The state developed a chart of five risk levels, from “remote’’ to “critical,’’ to serve as a relative measure of the likelihood of a human outbreak of the disease. The “high’’ designation is just below “critical,’’ a level not used this year.
Freetown’s recently infected pool contained a bird-biting variety of mosquito, rather than a type that bites mammals, including humans. But Bristol County Mosquito Project Superintendent Wayne Andrews said crossover breeds that bite both birds and mam mals can follow.
Freetown’s health agent, Paul Bourgeois, sent out local advisories last week telling residents to take the usual precautions: wear pants, socks, and long-sleeve shirts when outdoors at peak times, and use mosquito repellent containing the chemical combination DEET.
“We won’t be closing the parks early, but if something changes, we’ll readdress the issue,’’ Bourgeois said. He asked the Bristol County Mosquito Control office to spray Cathedral Camp in Freetown on Wednesday, since it is heavily used.
The first symptoms of EEE are high fever, stiff neck, headache, and lack of energy. The disease can cause inflammation and swelling of the brain. In some cases, it results in death.
Among its victims in Massachusetts are a 5-year-old Halifax girl who died in 2005, and a 9-year-old Middleborough boy in 2006. The disease is particularly dangerous in children 15 and younger and adults 50 and older.
Based on its track record since 1930, EEE generally follows a cycle three peak years out of every 11 to 15. The virus peaked in Massachusetts from 2004 through 2006, when 13 human cases resulted in six deaths. In 2007, there were no cases of EEE in humans, and last year a single case resulted in the death of a 73-year-old Newburyport man, believed to have been infected while camping in northern New England.
Even though the peak years are over, state health officials warn against assuming all risk has passed. “The disease doesn’t always follow the script, so precautions should be taken,’’ Lyons said.
Andrews said his agency has focused mosquito spraying around the area of last week’s infected pool and placed more mosquito collection traps there. All traps were emptied midweek and the mosquito pools sent to the state lab. Results should be released by tomorrow or early Tuesday.
Lakeville, Dighton, Fall River, Raynham, and Taunton are a step down from the high risk category this season, carrying the state designation of “moderate’’ risk for EEE.
Lakeville’s health agent, Lawrence Perry, said he believes aerial spraying done in past peak years should keep the town in good stead. “The state told us that would knock down successive populations,’’ he said.
Lakeville residents don’t appear to be worried about the local risk, even though Freetown is nearby. But, said Perry, “I expect the calls to come in once we get an infected pool in town.’’
Raynham’s health agent, Alan Perry, who’s not related to his Lakeville counterpart, wasn’t surprised to find his town on the state list for moderate risk. “We’re at least ‘moderate’ every year, and townspeople are aware of that,’’ he said. “We always just assume it’s here even if we don’t get an official positive.’’
The Raynham health agent said residents know to take the precautions.
If an infected pool is found in town, the local sports leagues adjust their schedules accordingly. “They set up their own curfews,’’ he said.
State epidemiologist Al DeMaria called the recently discovered Freetown pool “the first reminder’’ that EEE remains active.
“EEE isn’t confined to those areas, and people shouldn’t make the mistake of believing it is,’’ he said.
Christine Legere can be reached at christinelegere@yahoo.com. 
