DOYLESTOWN, Pa. -- Mosquito pools infected with West Nile Virus (WNV) have been identified in 20 of Bucks County, Pa.’s 54 municipalities, according to the Bucks County Health Department, which consequently has begun spraying an anti-viral agent in residential and park locations throughout the county.
No human cases have been detected, and no precise infected sites were identified.
“The Health Department conducts routine surveillance throughout the county in all 54 municipalities,” said Ray Buckley, supervisor, Quakertown district office. “WNV has been detected in mosquitoes collected from 20 of the municipalities. As of Aug. 15, there were no human cases of WNV in Bucks County.”
Spraying conducted by the county as part of its WNV surveillance and control program that runs through mid-October, recently treated parts of Lower Makefield, Newtown, Northampton and Wrightstown townships, plus Tyler State Park.
At those places, as well as others county-wide, truck-mounted equipment sprayed at a rate of 0.75 ounces per acre. The material used has a very low toxicity profile to mammals and the environment.
“When the prevalence of WNV in adult mosquitoes reaches a threshold that has the potential to infect the human population, we will conduct adult control operations in targeted areas that have been previously delineated,” he said.
WNV was detected last year in 27 Bucks County municipalities, with two confirmed human cases. Bucks County’s first WNV attack was in 2000, with significant results occurring in 2003 and 2018 when 15 and nine human cases respectively were confirmed.
“A majority of the work conducted is habitat reduction (removing standing water) and education,” said Buckley. “Where water cannot be removed, larval control is conducted.”
WNV is spread by mosquitoes to humans, birds, horses and other mammals, and symptoms can include fever, headache, body aches and fatigue. In rare cases, it can be fatal.
“Many individuals who may have had WNV are unaware, or it is undiagnosed,” said Buckley. “Symptoms are similar to other illnesses.”
Spread of the virus is amplified by birds.
“As adult mosquitoes are looking for a blood meal, they may obtain that from a bird such as crows, jays, ravens, grackles and hawks,” said Buckley. “Since birds fly much larger distances, they have the potential to carry the virus to other areas.”
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