Fort Bend County recently announced two cases of West Nile virus, but no mosquitoes there have tested positive.
The cases were in a child under 14 in Katy and a 38-year-old in Sugar Land.
The city has a three-pronged attack against West Nile virus, which includes spraying every Friday. Public Works Director Mike Goodrum said staying aggressive with spraying is just one key.
"We begin spraying around 9 o' clock, so if it's raining or if there is high winds, we will hold off spraying and then spray in the early part of next week. But if the weather holds up, we will be spraying Friday night and we will increase our spraying to twice a week so we will spraying next Tuesday as well," said Goodrum.
Placing larvacide pellets in standing water all over the city is one method officials are taking. Crews are also setting out mosquito traps, trying to attract the kind of mosquito that would carry West Nile.
"It's very proactive. Mosquitoes come from larva, so if we can get them at that source then we have a very aggressive program. We believe it's one of the most effective programs we have," said Goodrum.
As long as there is an elevated chance of West Nile virus, the spraying in Sugar Land will continue twice a week.
Officials said residents can make the biggest difference by making sure there is no standing water near their homes.