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

City health officials instructed Philadelphia medical providers to check patients for West Nile virus and other mosquito-borne illnesses and immediately report cases.

Mosquitoes infected with the West Nile virus have been detected in multiple boroughs, according to the New York City Health Department. At least 52 infected mosquitoes were detected in the Bronx, Queens and Staten Island by last Friday,