The number of mosquitoes confirmed to be carrying West Nile virus continues to climb toward record levels in the Lehigh Valley region, and officials are taking action.
Municipalities have been spraying or plan to spray for mosquitoes to limit the potential for human exposure. Northampton County on Tuesday announced that spraying will continue through October. Residents are encouraged to use insect repellent and once a week empty any standing water -- a mosquito breeding ground -- on your property.
So far this year, mosquitoes have been found to be carrying the disease in 29 municipalities across Lehigh, Northampton and Warren counties, according to the most recent data available from the Pennsylvania West Nile Virus Control Program and Warren County Mosquito Commission.
(The interactive map above shows each town. Selecting a marker shows how many positive samples have been recorded there.)
Officials who monitor the disease's spread have said that 2018 could be a record-setting year for West Nile in mosquitoes. Pennsylvania's record is 4,300 positive mosquito cases in 2012, according to the Penn State Extension. By mid-August that year, 1,105 cases had been identified; the state had more than 2,600 at the same time this year.
Warren County is all but assured to set a local record this year. The most recent numbers on the county mosquito commission's website put 2018's tally of positive bug samples at 30, just one shy of the record set last year -- and two months of monitoring remain.
West Nile virus comes from birds but is transmitted by mosquitoes. (Getty Images)
The number of positive samples varies widely from town to town. Many have seen just one or two, perhaps a handful more. The worst of it has been recorded in Allentown and Bethlehem, with 27 and 22 samples, respectively.
No human cases have yet been recorded in the Lehigh Valley. But at least four people with West Nile have been identified elsewhere in Pennsylvania -- one in Allegheny County, two in Franklin County and one in York County -- according to information from Pennsylvania's West Nile Virus Control Program. Those numbers had not been updated in about two weeks as of Tuesday.
In New Jersey, five human cases have been reported: one each in Essex, Hudson, Hunterdon, Somerset and Ocean counties, according to a state health department report dated Aug. 18.
West Nile virus symptoms and treatment
West Nile is a virus found in birds but spread by mosquito bites. It was first detected in North America in 1999. It can cause encephalitis, a brain inflammation.
Most people infected with West Nile never develop any symptoms, according to the CDC. About one in five will develop a fever with other symptoms, such as headache, body aches, joint pains, vomiting, diarrhea or rash. Most people with this type of West Nile virus disease recover completely, but fatigue and weakness can last for weeks or months, the CDC says.
More serious cases affect about one in 150 people. In these cases, the central nervous system is affected and encephalitis (inflammation of the brain) or meningitis (inflammation of the membranes that surround the brain and spinal cord) can develop, the CDC says. Symptoms can include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis. These conditions can affect anyone, but people over 60 years old and with certain other medical conditions are at greater risk.
There is no vaccine for West Nile virus, though over-the-counter pain relievers can help with some symptoms. In severe cases, hospitalization is required. Recovery can take weeks or months.
Consult your health care provider if you think you or someone you know has West Nile disease.
Steve Novak may be reached at snovak@lehighvalleylive.com. Follow him on Twitter @SteveNovakLVL and Facebook. Find lehighvalleylive.com on Facebook.