(Associated Press)

PITTSFIELD -- The latest round of heavy rain has health officials worried about a spike locally in the mosquito population, increasing the threat of West Nile virus and the more severe mosquito-transmitted Eastern Equine Encephalitis.

Thursday's steady downpours, atop the more than 9 inches recorded in Pittsfield the past three weeks, is expected to increase the number of watery breeding grounds for mosquitoes, according to Chris Horton, superintendent of the Berkshire County Mosquito Control Project.

"And if we have hotter weather conditions, that means more of a chance to detect the virus," Horton said.

"If we see a real spike in the adult mosquito population in certain areas, we may have to do some truck-mounted spraying," said Pittsfield Health Department Director Gina Armstrong.

The concern over an explosion in the mosquito population is warranted, recent data show. Pittsfield was designated a "high-risk" area in 2012 after an area resident was diagnosed with West Nile virus.

Among the mosquitos trapped in the city for testing last year, 13 were positive for virus and two for EEE. An additional 16 mosquitoes elsewhere in Berkshire County also tested positive for West Nile.

Symptoms of West Nile virus include headaches and fever. People suffering from EEE experience headaches, high fever, chills and vomiting. In rare cases, the illness may cause disorientation, seizures and induce a coma.

Massachusetts Department of Public Health officials say it's difficult to predict the severity of this year's statewide mosquito population.

DPH infectious disease specialist Alfred DeMaria said in a recent Eagle interview that the prevalence of the bug-borne West Nile and EEE will be known by the middle of July or August.

Next week, the local Mosquito Control Project will begin trapping mosquitoes and send the samples to the DPH for testing, Horton said. The state-funded Mosquito Control Project serves Pittsfield, Clarksburg, Hinsdale, Otis, Tyringham, Stockbridge, Sheffield, and as of July 1, Richmond. Berkshire cities and towns must vote to join Mosquito Control.

Meanwhile, Pittsfield officials are working with Mosquito Control to mitigate the role beavers play in creating breeding grounds for mosquitoes.

Last year, mosquitoes trapped in shallow water behind five beaver dams in the city tested positive for West Nile, according to Horton.

One possible solution is draining excess water unnecessary for beaver habit, said Pittsfield's conservation agent, Robert Van Der Kar.

"I've designed some water level control devices that have been successful the past," he said. "We want to strike a balance between the beavers and public health."

Armstrong noted the city is seeking a state grant toward the purchase of a water control device.

"We'll do a pilot program at one location, and if [it's] effective, we'll look at other areas," she said.

To reach Dick Lindsay:
rlindsay@berkshireeagle.com,
or (413) 496-6233.

How to avoid bites

To prevent mosquito bites:

n Apply insect repellent with DEET when outdoors.

n Be aware of peak mosquito hours from dusk to dawn.

n Wearing long sleeves, long pants and socks when outdoors will help keep mosquitoes away from your skin.

n Drain standing water from flower pots, bird baths, wading pools and other shallow water containers as they are prime breeding areas for mosquitos.

n Install or repair screens to keep mosquitoes outside.

Source: Mass. Department of Public Health