The Florida Department of Health in Duval County has confirmed a human case of West Nile virus infection.
The individual is believed to have acquired the virus locally, the department said in an Aug. 31 news release. In response, the department is coordinating with Jacksonville Mosquito Control for surveillance and ground spraying.
The department reminds residents to take basic precautions to avoid being bitten by mosquitoes.
➤ Meet the mosquito, the world's deadliest animal
The Department of Health continues statewide surveillance for mosquito-borne illnesses, including West Nile virus infections, Eastern equine encephalitis, St. Louis encephalitis, malaria, chikungunya, and dengue. Residents are encouraged to report dead birds to the Florida Fish
and Wildlife Conservation Commission’s site.
The West Nile case comes amid a wave of newly reported cases of dengue across Florida.
As of Aug. 22, 41 dengue cases have been reported in Florida in 2026, including 18 reported cases in one week, Aug. 16-22, according to Florida Department of Health reports.
Here's what you should know about mosquito-borne illnesses in Florida, symptoms to watch for and how best to prevent mosquito bites.
How many types of mosquito-borne illnesses are there in Florida?
FDOH compiles weekly data on the following mosquito-borne viruses in a report called "Florida Arbovirus Surveillance":
- West Nile virus (WNV)
- Eastern equine encephalitis virus (EEEV)
- St. Louis encephalitis virus (SLEV)
- Dengue virus (DENV)
- Chikungunya virus (CHIKV)
- Zika virus (ZIKV)
- California encephalitis group viruses (CEV)
- Malaria
Mosquito-borne illness alerts, advisories issued for these Florida counties
A mosquito-borne illness advisory has been issued for the following counties:
- Alachua
- Leon
- Palm Beach
- Pasco
- Walton
Duval County was added to the list on Aug. 31 after a reported case of West Nile virus.
A mosquito-borne illness alert has been issued for the following counties:
- Hillsborough
- Miami-Dade
- Pinellas
"A mosquito-borne illness advisory means the public should take precautions to reduce mosquito bites due to factors indicating local disease such as positive sentinels, very few presumptive or positive human cases, or other justifications," according to Sarasota County.
"A mosquito-borne illness alert means that there has been heightened disease activity, a significant increase in vector (disease capable) mosquito populations, or an increase in locally-transmitted human cases.
"Residents should continue to take precautions, but exercise additional caution in preventing mosquito bites."
What are the best mosquito repellents to use?
According to the Florida Department of Health, repellentswith the following active ingredients provide the best protection:
- DEET
- Picaridin
- IR3535
- Oil of lemon eucalyptus
- Para-menthane-diol
- 2-undecanone, a plant-derived ingredient
'Drain and cover' helps keep mosquitoes away
The FDOH offered this advice to help keep mosquitoes away from your Florida home:
Drain
- Drain water from garbage cans, old tires, pool covers, or any other containers where water collects.
- Empty and clean birdbaths and pet water bowls at least once or twice a week.
- Protect boats and vehicles from rain with tarps that don’t accumulate water.
- Maintain swimming pools in good condition and ensure they are appropriately chlorinated.
- Empty plastic swimming pools when not in use.
Cover
- If you must be outside when mosquitoes are active, cover up.
- Apply mosquito repellent to exposed skin and clothing.
- Use mosquito netting to protect children younger than 2 months old.
For more information on mosquito prevention, visit the Department of Health's mosquito prevention webpage or contact DOH-Duval at 904-253-1850.
This story was created by Gary Mills, gmills@jacksonville.com, with the assistance of Artificial Intelligence (AI). Journalists were involved in every step of the information gathering, review, editing and publishing process. Learn more at cm.usatoday.com/ethical-conduct.
This article originally appeared on Florida Times-Union: West Nile virus case confirmed in Duval County; advisory issued
