Various factors led to high rate of West Nile virus in Franklin County

October 22, 2012|By JENNIFER FITCH |

WAYNESBORO, Pa. — Franklin County, Pa., experienced a high rate of West Nile virus this year, mirroring state and national trends.

“We had unprecedented numbers,” said Raymond Eckhart, county coordinator.

With 69 total positives in mosquito samples, a dead bird and one human case, Franklin County is 18th highest among Pennsylvania’s 67 counties for 2012.

Eckhart said scientists are still speculating why instances of West Nile virus were high this year. He said the mild winter in 2011-12 might have affected the habits of birds.

“The start of the (West Nile) season was early because of the early warm weather and the mild winter,” Eckhart said.

Also, the county had a widespread outbreak of the “Asian tiger” mosquito that is active during the day, not just at dawn and dusk. He described that mosquito as having an “aggressive, persistent biting behavior” for mammals.

Pennsylvania had 25 human cases this year, ranking it 28th in the nation, according to a news release from three state agencies.

The state had 47 veterinary samples (third in nation), 3,409 infected mosquito samples (second in nation), and 134 infected birds (third in nation), the news release stated.

Eckhart said mosquito samples are collected through routine surveillance of traps in the county and in response to calls from the public.

Spraying to control mosquito populations is typically done with truck-mounted equipment, although planes were used in Franklin County in 2005 and 2006, when it had more mosquito samples test positive for West Nile virus than any other county in Pennsylvania.

Pennsylvania Department of Environmental Protection officials recommend residents eliminate areas of standing water to minimize spots where mosquitos can breed. Some mosquitos go from egg to adult in five to six days.

“They absolutely, 100 percent need standing water to breed,” Eckhart said.

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