PITTSFIELD -- Tests have confirmed the presence of West Nile Virus in mosquitos here and in the Ashley Falls section of Sheffield, according to the state Department of Public Health.
These are the second and third positive tests for West Nile in Berkshire County this year, following a similar result in Pittsfield on June 26. Samples were collected at surveillance sites on July 13 and 17. West Nile was first detected in the area last September.
The Berkshire County Mos quito Control Project will be placing additional surveillance traps in the area where the virus was found and catch basins have been treated with a biological larvicide to reduce the population of the mosquito species.
Christopher Horton, superintendent of the Berkshire Coun ty Mosquito Control Project, said positive tests in this region typically come at the end of Aug ust or early September, so it's surprising to have a third positive test before the end of July.
West Nile grows in birds and is spread by mosquitos.
Horton said there is an amplification effect on the disease caused by more frequent contact between birds and the mosquitos. Horton said he believes the early occurrences this year could be tied to the dry weather conditions, which have resulted in birds and mosquitos searching out some of the same scant water supplies.
There have been 15 instances of West Nile detection in mosquito populations in Massa chusetts in 2012. There have been
Avoiding West Nile
* Avoid outdoor activity between dusk and dawn, when mosquitos are active.
* When outdoors, use repellent, wear long pants and long-sleeved shirts.
* Drain standing water, where mosquitos lay eggs.
* Install or repair screens.
* Eighty percent of infected will exhibit no symptoms.
* Fewer than 20 percent will exhibit symptoms such as fever, headache, body aches, nausea, vomiting and sometimes swollen lymph glands.
* Less than 1 percent of those infected will develop severe illness. People over 50 are at a higher risk.
* Between 2000 and 2010, 67 people have reported West Nile infection in Massachusetts. Six have died.
Source: Massachusetts Department of Public Health