With seven documented cases of malaria reported in Sarasota County this year, the county’s Mosquito Management Services team spent the summer on high alert.

The cases were reported in May, June and July, prompted by mosquitos carrying the Plasmodium vivax infection.

Mosquito Management Services manager Wade Brennan says the team increased its spray treatments in response to the outbreak, but dry weather in the first half of the summer also helped control the threat. Brennan says extra treatments focused on high-risk areas in north Sarasota.

“With malaria, we were dealing with a smaller focused area and a species [of mosquito] that doesn't fly that far,” Brennan says. “That allowed us to changed our focus [from] wider spread throughout the entire county to northern Sarasota. We were able to put the boots on the ground and get into the wood lots and trenches and canals—areas like that.”

Along with the malaria threat, effects of Hurricane Ian and Hurricane Idalia also increased the risk of mosquito-borne diseases ahead of and following this year's unusually dry summer. That resulted in an increased number of spray treatments in the county, with 51 truck missions completed in the 2023 fiscal year—Oct. 1, 2022 through Sept. 30, 2023.

The previous four years averaged 26 truck missions a year while aerial missions averaged 32. The 2023 fiscal year saw aerial missions increase to 35.

As treatments increased, so did the cost, but Brennen says the summer drought helped to offset the expenses. For the 2023 fiscal year, the county contracted out spraying services and purchased pesticides that cost a total of $1.07 million. Total expense in 2022 was $870,000.

The team uses a combination of adulticides and larvicides for treatment, and they rotate them to reduce chances of resistance. Pesticides used include Deltamethrin, Etofenprox, Naled, permethrin/piperonyl butoxide, Sumithrin, bacillus thuringiensis israelensis, bacillus sphaericus, Spinosad, Methoprene, Cocobear mineral oil and mosquito fish.

Brennan says 90 percent of the treatments utilize larvicides, meaning they do not kill other bugs but rather only mosquito larvae.

“They're specific to mosquitoes only,” Brennan says. “But our adulticides can kill other insects, so that's why we apply at night. We're targeting and making sure that it's not affecting our bees, our butterflies and all our beneficial insects.”

Brennan notes that while the malaria threat has passed, the area now enters the annual timeframe for increased West Nile threats. To help reduce risks of disease, he recommends people take protective measures.

“Our biggest problem is getting into people's backyards and controlling those mosquitoes," he says. "We  need everybody to make sure to dump and drain any kind of container or standing water around their house. We also need everybody to make sure that they keep up on self-protection against mosquito bites. Then we can focus on the larger neighborhood or area treatment."

To avoid West Nile and other mosquito-borne diseases, Brennen also recommends wearing long, loose-fitting clothing and using mosquito repellent approved by the Centers for Disease Control and Prevention. Residents can also request assistance and mosquito management services by calling 311.

For information on Sarasota County Mosquito Management Services, click here.

Sarah Owens in a reporter for the Community News Collaborative. Connect with her at [email protected].