Dry summer meant fewer EEE-infected mosquitoes

A dry summer has yielded at least one benefit: fewer mosquitoes carrying highly lethal Eastern equine encephalitis.

A state health report presented yesterday shows that through Friday, disease trackers had found only 22 pools of mosquitoes carrying the virus. That compares with 121 pools of infected mosquitoes through the same period last year.

Dr. Alfred DeMaria, the state's director of communicable disease control, attributed the decline to the lack of rainfall, which is necessary for mosquitoes to breed robustly. The lack of rain, DeMaria said, has been most pronounced in the Southeastern corner of the state, long recognized as a hotbed of Eastern equine activity.

Another mosquito-borne ailment, West Nile virus, appears to be at a level similar to last year, DeMaria said.

Eastern equine encephalitis is the deadliest of all ailments spread by mosquitoes, killing one-third to one-half of people who contract the illness. No human cases of the disease have been reported in Massachusetts this year.

Three cases of West Nile virus have been documented in the state, but investigators said they do not believe any of those infections was acquired in Massachusetts. Two of the people with the disease were visiting Massachusetts and appear to have contracted the virus before arriving in the Bay State. Investigators said the third patient, a Boston man, was exposed while in Montana.

To avoid contact with infected mosquitoes, the Massachusetts Department of Public Health recommends limiting outdoor activities from dusk to dawn, which are peak biting times for mosquitoes. Otherwise, wear as much clothing as comfortable and apply insect repellent such as DEET, permethrin, picaridin, or oil of lemon eucalyptus.

DEET should not be used on infants under the age of 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 under 3 years old.