To slow the aggressive insects, Harris County Health officials and residents will need to work together.
Daisy Cedillo loves to run in Memorial Park but said she feels under attack.
"Honestly, they're going crazy; I don't know what's in the air," Cedillo told ABC13.
What's in the air? Heat, humidity, and flooding rains that lead to standing water are perfect breeding grounds for the southeast Texas mosquito.
Dr. Max Vigilant, the director of mosquito control for Harris County, says the early heat and flooding rain have caused the mosquito season to rage.
"We have flood water, mosquitos in the flood water. They're the ones that chase people around; they are aggressive," Vigilant said.
Vigilant's office does surveillance and collects mosquitos from traps daily. They're separated, looking for West Nile virus.
Laboratory Manager of Operations Lindsey Labouf says they test for West Nile weekly.
"We test three times a week for mosquitos, and birds test once a week," Labouf said.
According to Vigilant, if positive mosquitos are found, spray trucks are sent out.
"If positive mosquitos are found, spray trucks are sent, so we know we have to knock out a 5-mile radius around the area that was positive," Vigilant said.
Five cases of West Nile have been reported so far this year. Mild cases usually have symptoms similar to the flu, while serious cases can cause tremors, seizures, and confusion.
To protect yourself from aggressive critters, wear insect repellent, tip over containers with standing water, get rid of old tires and debris, and clean drains.
"We're asking them to do those things. Help protect themselves. We can do the other stuff. We can do the rest treating the areas, but residents have to help us," Vigilant said.