Montgomery County alone has 13 confirmed human cases of the West Nile virus.
The county began an aerial assault on mosquitoes Saturday night hoping to prevent the spread of the disease.
More sprays will take place over the course of several nights that start at 8:30 p.m. to about midnight. They will take place through Aug. 30.
County leaders made the decision earlier this week when there were just 10 confirmed cases of West Nile. Only three people had the virus at this time last year.
The most recent cases this week include a woman in her 50s, a man in his 60s and a teenager.
All of them are in stable condition. However, the virus has contributed to the death of an elderly man.
Crews have already been using ground sprays to control the mosquito population. But that hasn't worked as well as expected, so they're hoping aerial sprays will do the trick.
Precinct 3 and parts of Precinct 2 and 4 will be included.
Harris County has had one West Nile-related death and is also using aerial sprays to control mosquitoes.