West Nile Virus has arrived on the Vineyard. On Thursday the Massachusetts Department of Health announced that a single mosquito collected in Tisbury tested positive for the disease and health officials are asking Islanders to take reasonable preventive measures.
The infected mosquito was collected in a baited trap in Cranberry Acres off Lambert’s Cove Road in Vineyard Haven by Dukes County integrated pest management director T.J. Hegarty. It was then shipped for testing at the state department of public health laboratory. West Nile Virus can cause symptoms ranging from a mild fever to more serious diseases like encephalitis or meningitis, but on Thursday Tisbury health agent Maura Valley played down the severity of the illness.
“In most people they don’t have any symptoms if they get West Nile Virus,” she said. “But some people can get sick from it and some people can get very sick from it, especially people over 50.”
Only about one per cent of people infected with West Nile develop severe illness, while 80 per cent exhibit no symptoms according to the state Department of Public Health.
Ms. Valley said homeowners can help reduce populations of disease-carrying mosquitoes by draining standing water, and she recommended the use of insect repellent when outdoors.
“We just want people to be aware of it so that they take precautions,” the health agent said. “Be careful if you’re out at dawn or dusk when the mosquitoes are at their worst and make sure that you use mosquito repellent that contains DEET.”
Ms. Valley said that she was not aware of any human contractions of the illness on the Island.
This is not the Island’s first encounter with the virus, which was first identified in the United States in 1999. Although the testing of Island mosquitoes is new, between 2000 and 2008 health officials did submit dead birds, mostly crows, for testing by the state health department. Out of almost 200 Vineyard birds tested during that span, 20 tested positive for West Nile. The state no longer tests dead birds, as mosquito testing is more reliable. Between 2000 and 2010 there were 67 human cases of West Nile reported statewide, seven of which proved fatal.
Every Island town participates in the county’s mosquito monitoring program except Oak Bluffs which voted down joining the Dukes County integrated pest management program on two separate occasions, at an annual and special town meeting earlier this year. As a result there is no monitoring in the town for West Nile and other mosquito-borne illnesses.
Mr. Hegarty said that at this point there are no county-wide plans to combat the disease.
“It’s an educational process at this point and we’re just collecting data,” he said. “If the positive identifications rise, something more drastic may have to be done but that’s up to the department of public health and the boards of health involved, it’s not the county’s call.”
For his part, Mr. Hegarty said he does treat storm drains at the airport business park and at the two Cronig’s supermarkets with an insecticide that targets mosquitoes, but that was the extent of the county’s anti-mosquito campaign. Mr. Hegarty said there are other ways homeowners can help stem the proliferation of the insects such as drilling holes in the bottoms of old tires to prevent water from collecting, citing the case of the West Nile-carrying tiger mosquito as a cautionary tale.
“They came into the country in 1985 on a shipment of recycled tires from Japan and hatched out in Houston, Texas,” he said.
Mr. Hegarty was critical of Oak Bluffs’ decision not to join the county’s integrated pest management program and lauded the benefits of the county’s mosquito monitoring.
“It’s been a true example of an intermunicipal program that is doing something positive in the interest of the public health of this Island,” he said.