Mosquitoes testing positive for West Nile virus have been detected in Dallas. 

The city announced Tuesday that controlled areas would be sprayed with insecticide following the discovery.

On May 14, West Nile-positive mosquitoes were found in Fort Worth and Grand Prairie.The first West Nile-positive Texan was reported Tuesday — a Houston-area resident diagnosed with West Nile neuroinvasive disease, the rare, serious variant of the virus’ symptoms.

West Nile is a mosquito-borne disease transmitted to people through mosquito bites. Public health officials in Dallas-Fort Worth recommend taking precautions against mosquito bites and eliminating standing water. 

Most people bitten by West Nile-positive mosquitoes never develop symptoms. For the 20% who do, fevers, headaches, nausea, joint pain and body aches are common. In rare cases, according to the CDC, more severe complications impacting the brain and nervous system are possible.

In a news release, the city detailed plans to spray the Central and West Oak Cliff areas between Whitewood Drive, Periwinkle Drive, Rugged Drive and Myrtlewood Drive. The Red Bird area will be sprayed as well, between Midvale Drive, Woodshire Drive, R.L. Thornton Freeway and Seaside Drive. Spraying will take place between 9 p.m. and 5 a.m. in both locations Wednesday and Thursday.

The city recommends residents in the affected areas stay inside while the spray is being distributed in order to avoid contact, though the insecticide has been approved by the Environmental Protection Agency. Should residents come in contact with the spray, they are advised to wash the area with soap and water.

According to the Texas Department of State Health Services, counties in North Texas regularly collect and test mosquitoes for the virus.