West Nile Virus has been found in at least three areas of Suffolk, city officials announced Wednesday afternoon.

Mosquitoes in the areas of Lake Kennedy, Lloyd Street and North Street tested positive for the virus, the city said in a press release.

“Citizens should know that West Nile Virus activity is present in downtown Suffolk, and everyone should protect themselves while engaging in outdoor activities,” Charles Abadam, the city’s superintendent of mosquito control, said in the press release.

West Nile Virus is a mosquito-borne disease with effects that can range from mild flu-like symptoms to severe illness. No human cases of the disease have been reported in Suffolk.

West Nile Virus is the second serious virus to be found in the city’s mosquito populations this year. Mosquitoes from areas across the city already had tested positive for Eastern Equine Encephalitis, a disease that is usually deadly in unvaccinated horses and can cause human problems in rare cases.

Two horses in Suffolk already have been confirmed to have been victims of the EEE virus.

As a result of the West Nile Virus discovery, the city’s press release stated, mosquito-control operations are intensifying in the affected areas. The areas are being subjected to “increased mosquito surveillance, treatment of standing water and evening spray applications for adult mosquitoes.”