Boston woman ill with West Nile

New warnings on mosquitoes

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By Stephen Smith
Globe Staff / August 28, 2010

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As two more human cases of mosquito-borne illness were reported in the state, Massachusetts disease trackers cautioned yesterday that this week’s heavy rains and the return of hot weather could spawn a new wave of biting insects.

The warning came as authorities reported that a 43-year-old Plymouth County man was hospitalized and seriously ill with eastern equine encephalitis. A 46-year-old woman from Boston was diagnosed with West Nile virus and hospitalized but is now at home recovering.

Earlier this month, a Rhode Island man who had been golfing in Southeastern Massachusetts, a swath of the state long recognized as a hot spot for mosquito-borne diseases, tested positive for Eastern equine encephalitis. Several weeks after falling ill, he remains hospitalized in critical condition, a spokeswoman for Rhode Island’s Health Department said.

Not since 2007, when six people were diagnosed with West Nile virus, have this many people become infected in Massachusetts with viral ailments spread by mosquitoes.

State disease specialists said they believe the Plymouth County man was infected after planes took to the air to douse Southeastern Massachusetts with pesticide, a campaign estimated to have eliminated about 80 percent of mosquitoes.

“We strive to reduce the risk, but we can never eliminate it while there are still mosquitoes present,’’ said Dr. Alfred DeMaria, the top disease tracker at the Massachusetts Department of Public Health. “And there will be mosquitoes till the first hard frost. It’s an important message for people to continue to avoid mosquitoes and mosquito bites.’’

DeMaria said it was unlikely that aerial spraying would resume, largely because it is later in summer and spraying from the air, an expensive proposition, would prove less effective. Trucks have continued to spray in neighborhoods with high mosquito counts, he said.

The last time a Massachusetts resident was diagnosed with West Nile was in 2008.

The Boston woman who contracted the disease — her identity, like that of the Plymouth County man, was not disclosed because of patient confidentiality rules — was first diagnosed with meningitis. Lab tests returned yesterday showed she had West Nile, which can cause meningitis.

Few people who contract West Nile become seriously ill, but those who do can face life-altering consequences or even death.

“There’s no way to predict with certainty what 1 percent of people who get infected are going to be the ones to become severely ill,’’ said Dr. Anita Barry of the Boston Public Health Commission, “so we advise everyone to avoid being bitten.’’

DeMaria said authorities will carefully monitor mosquito populations in the coming days, fearing that the mix of rain and hot weather could produce a bumper crop of new insects. Still, the mosquitoes will arrive uninfected, and it typically takes several weeks for enough of the insects to acquire the virus that they pose a widespread threat.

To avoid being bitten, specialists recommend staying inside from dusk to dawn. If outdoor activity is necessary at night, wear long sleeves, long pants, and socks. Bug repellents such as DEET, permethrin, picaridin, and oil of lemon eucalyptus can also provide protection. DEET should not be used on infants younger than 2 months and should be used in concentrations of 30 percent or less on older children. Oil of lemon eucalyptus should not be used on children younger than 3.

Homeowners can take measures that reduce mosquitoes’ breeding grounds, including draining flower pots, wading pools, and gutters.

Stephen Smith can be reached at

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