West Nile virus is a viral disease that is transmitted by mosquitoes. The virus is a member of the Flaviviruses, which also includes Zika, dengue and yellow fever viruses. The virus was first identified in the West Nile district of Uganda in 1937,

Doctors urged to look for West Nile virus symptoms in patients near Philadelphia after a positive case was detected in the city.

This month, as mosquito activity reaches its peak, health officials have detected West Nile in additional Bucks County populations, the spokesperson said: one positive test in the Hulmeville/Bensalem area, and one in Quakertown. The first positive result in Philadelphia was identified at Pennypack Park in early July.

Philadelphia health officials warn of West Nile virus in local mosquitoes, urging residents and medical professionals to take precautions and watch for symptoms. No human cases reported yet.

Philadelphia Department of Public Health reports the year's first cases of West Nile Virus infections. Here's what you need to know about the virus.

Philadelphia health officials are warning residents after West Nile virus was found in mosquitoes in Northeast Philadelphia earlier this month.