Orange County Mosquito Control’s phone hasn’t been ringing the same way it usually does this time of the year. That’s because Florida’s current drought has reduced mosquito populations.
That sounds like good news, but Central Florida mosquito control groups are hard at work ahead of the rainy season to curb the possibility of a population boom and try to mitigate the transmission of mosquito-borne diseases.
“I'm concerned with the possibility of having some West Nile virus,” said Steve Harrison, the director of Orange County Mosquito Control.
Paradoxically, research shows that as drought conditions lessen the population of mosquitoes, they increase the chance for West Nile virus cases to develop. With fewer watery-breeding options, mosquitoes will head to ponds or lakes. So, too, will birds, which are also looking for water.
“Because you have the birds and the mosquitoes, they're all more congested, if you will, and so the transmission of West Nile can be higher,” Harrison said.
So would rain help the problem? That’s complicated, especially if the drought lasts a long time before the rains return, Harrison said.
“Then later on, when you start getting more breeding areas, now you're taking these mosquitoes, and these birds that have previously been infected with this virus, and you can go into other areas and start infecting other birds,” he said.
In addition to West Nile, dengue has also become a concern in Central Florida. The mosquito breed aedes aegypti is famous for carrying the dengue virus. It’s also known for laying eggs that can be dormant for up to eight months until the rains come. That can lead to a population boom.
In Brevard County, the situation is even trickier.
Black salt marsh mosquito eggs are buried in the soil of the Indian River Lagoon and can lie dormant for years until water levels allow them to start developing.
“So when the water levels come up, it fills in all the little holes, potholes, and then we can have some mosquitoes emerging from all these little pockets out in the marsh, and it gets a little unpredictable,” said Joseph Faella, the director of Brevard Mosquito Control.
Mosquito control groups are trying to reduce reproduction.
So far this year, Brevard County has released 220,000 native mosquito fish species to consume mosquito larvae.
As of last year, Brevard also has a new program releasing X-ray sterilized male Aedes aegypti mosquitoes into the area to mate with female mosquitoes. The eggs don’t hatch.
“And the males do not bite. They're not equipped to,” Faella said.
That program began in October, just after the county experienced a spike in dengue cases. In total, Brevard reported 35 locally acquired dengue cases, accounting for more than half of the state’s 2025 total – 62 cases.
The cases stood out as an abnormality. Dengue is not endemic in Florida. According to the Florida Department of Health’s 17-year online surveillance reports, it’s the first year any Central Florida county reported local dengue.
“After a season as we had in 2025, we're taking extra precautions because we just don't want to see that repeat,” Faella said.
Central Florida day and night crews are going to residential areas to apply an EPA-approved repellent. They’re also reminding residents to toss any containers gathering water.
“One 5-gallon bucket can breed thousands of mosquitoes and wreak havoc, not only for you but also for your neighbors within a city radius,” Harrison said. “We're out looking for those cryptic areas, we're treating them, and we're inspecting. We are night spraying in certain areas because the whole entire (Orange) county isn't dried out.”
Harrison is also reminding residents purposely collecting water for gardening to prevent mosquitoes from using it for breeding by applying a mesh screen over the open container.
County mosquito control groups are doing their best to get ahead of mosquito populations for when the rain does return.
But predicting mosquito behavior is kind of like predicting the weather, Harrison said. “You can't really 100% predict the weather, and we can't 100% predict what our mosquito season will be, either.”
