West Nile Cases Down Notably In 2020 In Montgomery County

MONTGOMERY COUNTY, PA — For the second straight year, the number of positive tests of West Nile Virus in mosquitoes around Montgomery County is down. Should those statistics hold, it marks a welcome trend in a year that has brought no shortage of health concerns to area residents.

The statistics are taken from the latest numbers compiled by the Pennsylvania Department of Environmental Protection's West Nile Virus Control program. They show that the county has seen 58 positive cases of the virus in mosquitoes as cooler weather approaches with autumn.

The 2020 numbers thus far are much more in line with 2019's numbers, a year which saw 54 positive samples collected. But results looked much more different as recently as a few years ago.

The county had 422 positive samples in 2018, 144 in 2017, 147 in 2016, and 154 in 2015.

There has not been a human in the county who has tested positive for the virus since 2018, when a 59-year-old from Montgomery Township and a 66-year-old from Lower Merion Township both tested positive.

Thus far the county Office of Public Health has worked with the DEP to conduct chemical sprayings in two parts of the county: Norristown and Lower Moreland. In previous years, the late summer months saw a dozen if not more such sprayings, in an effort to control the spread of the virus. While 2017 and 2018 especially were noted "higher than usual" years for West Nile mosquitoes in the county, 2020 has been a welcome sharp reversal of that trend.

In addition to spraying, strategies to combat the virus include removing standing water from properties, especially in old tires and other places where moisture lingers and serves as a breeding ground.

West Nile can cause febrile illness, encephalitis (inflammation of the brain) or meningitis (inflammation of the lining of the brain and spinal cord), according to the CDC. The elderly and those already sick are those most vulnerable to the virus.

West Nile virus appeared for the first time in Pennsylvania in birds, mosquitoes and a horse in 2000.