NewsDesk  @infectiousdiseasenews

The Philadelphia Department of Public Health (PDPH) has recently identified the city’s first symptomatic human West Nile virus (WNV) infection for the 2021 season in an adult resident who became ill with neuroinvasive WNV in early August.

Image by Bruce Emmerling from Pixabay

Since June, mosquitoes infected with WNV have been detected throughout Philadelphia and surrounding counties in Pennsylvania and New Jersey.

Over the next few weeks, the risk of human WNV infection is expected to increase in the area and persist through October while infected mosquito pools are present.

WNV is caused by an arthropod-borne Flavivirus and transmitted by the bite of infected mosquitoes.
Symptoms develop 2-14 days after exposure. About 20% of infected persons develop WNV fever, which is generally characterized by fever, headache, muscle and joint pain, vomiting, diarrhea, or a transient rash.

Neuroinvasive disease, most commonly meningitis, encephalitis, or acute flaccid myelitis, develops in <1% of infected individuals.

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Treatment for WNV infection is supportive. Most patients with WNV fever or meningitis fully recover without long term effects. Recovery from WNV encephalitis or acute flaccid myelitis can take several weeks to months with long lasting neurologic deficits. The case fatality rate among persons with severe
illness is 10%.