JONATHAN M. METSCH, Dr.P.H. – Tracking Emerging Public Health Challenges – September 20, 2026 – CHIKUNGUYA/ DENGUE
“People can become infected with chikungunya virus when mosquitoes feed on another infected person and then bite them.
People infected with chikungunya virus have high enough levels of virus in their blood (viremia) during the first week of illness to transmit the virus to mosquitoes. Risk of further spread of chikungunya virus increases if people with viremia are bitten by uninfected mosquitoes.
Because of the high level of virus in blood, spread can also occur through:
Blood transfusion (probable)
Exposure to the virus in the laboratory
The virus does not spread from person to person through coughing, sneezing, or touching.” (1)
“Mosquito bites can be more than a nuisance this summer — they can make you sick.
The state leads the nation in dengue cases this year with 270 reported. Increasingly, residents aren’t just acquiring the virus while traveling abroad — they are getting bitten right at home. Mosquito control experts note that peak dengue season runs from July through September.
As many as 111 people as of early September have contracted locally acquired dengue in six Florida counties this year. While eight of these cases were in Miami-Dade and Palm Beach counties, a striking 95 occurred in Hillsborough County, where mosquito control teams are working overtime and ramping up spraying. The death of an 80-year-old South Tampa woman may be linked to a dengue infection.
A common dengue symptom is a sudden high fever starting four to 10 days after a bite, followed by a skin rash a few days later. Treatment is limited to rest, fluids, and pain relievers.
“There is no cure or antiviral medications for dengue,” said Dr. Rana Chakraborty, division chief in Pediatric Infectious Diseases at the University of Miami.
Many infected individuals remain completely unaware.
“A lot of people can get bitten, acquire dengue, and nothing happens to them,” Chakraborty said. “Only a fraction have symptoms.”
For about 1 in 20 people, dengue progresses to a severe level — triggering repeated vomiting, nosebleeds, stomach pain, and organ failure — often requiring hospitalization.
While many species of mosquito inhabit Florida, only two transmit dengue: Aedes aegypti and Aedes albopictus. Recognizable by their dark bodies and distinct white-striped legs, these daytime biters peak just after sunrise and before sunset. They also transmit Zika, yellow fever, and chikungunya.” (2)
“The Florida Department of Health is proposing a rule to allow pharmacists to administer a vaccine for chikungunya disease.
Chikungunya disease, a viral infection, is a mosquito-borne illness that can cause fever and severe joint pain. It can be confused with dengue and Zika, which makes the illness hard to diagnose, according to the World Health Organization.
In Florida, there have been 189 reported cases of chikungunya disease so far this year, according to DOH’s reportable diseases frequency report.
Most of those cases, 120, were reported in Miami-Dade County.
About 92 of the cases were reported in January of this year.” (3)
“The Florida Department of Health reported an additional 41 locally acquired dengue fever cases during the past week, bringing the total in the state to 152.
Of the 41 new cases, 39 of the cases are reported from Hillsborough County, while the other cases were reported from neighboring Pinellas County (2).
In 2026, 152 cases of locally acquired dengue have been reported in Hillsborough (134), Miami-Dade (7), Orange, Palm Beach, Pasco (2), and Pinellas (7) with onset in July (21), August (124), and September (7). (4)
There were no reports of dengue acquired in Florida since 1934, then in 2009, a local outbreak was reported in Key West. Since that time, outbreaks and sporadic autochthonous dengue cases have been reported.
Dengue infection is acquired through the bite of certain species of mosquitoes, primarily Aedes aegypti, but also Aedes albopictus, both of which are present in Florida.
Dengue fever can be a painful, debilitating disease but is rarely fatal. Symptoms appear 3-14 days after the bite of an infected mosquito and include sudden onset of fever, severe headache, eye pain, muscle and joint pain (giving the disease the nickname “breakbone fever”), and bleeding. Gastrointestinal symptoms like vomiting and diarrhea may also be present in some cases. Dengue fever symptoms usually lasts 4-7 days. The disease is often diagnosed incorrectly because the symptoms are similar to influenza and other viruses.
Dengue hemorrhagic fever is a rare but more severe form of dengue infection that can be fatal if not recognized and treated with supportive care. The primary risk factor for hemorrhagic fever is previous infection with a different dengue serotype (i.e. getting DENV-2 if you have already DENV-1 puts you at increased risk of hemorrhagic fever).
There is no treatment for dengue fever or dengue hemorrhagic fever, but quick recognition and management of symptoms and complications is effective at preventing deaths.
In addition, health officials reported the first in the state this year locally acquired chikungunya case in Miami-Dade County.” (4)
Chikungunya Cases in US Travelers Reach 89 with No Local Spread as Six Countries Carry Outbreak Notices, By Elena Vega, https://www.medicaldaily.com/chikungunya-us-travel-cases-cdc-surveillance-data-478458
Chikungunya Cases Rise to 300 in Costa Rica as New Outbreak Hits San José, https://ticotimes.net/2026/09/18/costa-rica-chikungunya-cases
You’re not imagining it, there are more mosquitoes in the UK this year, https://inews.co.uk/news/politics/youre-not-imagining-it-there-are-more-mosquitoes-in-the-uk-this-year-4761087
Mosquito that carries dengue, Zika, and chikungunya found breeding in UK for first time, https://www.bmj.com/content/394/bmj-2026-100761
(Pakistan) Health Authorities Intensify Measures as Chikungunya Outbreak Spreads, https://propakistani.pk/2026/09/07/health-authorities-intensify-measures-as-chikungunya-outbreak-spreads/
Doctor explains: Dengue, malaria or flu? How to tell the difference and when to seek help, https://www.firstpost.com/health/doctor-explains-dengue-malaria-or-flu-how-to-tell-the-difference-and-when-to-seek-help-14041763.html
1.Chikungunya: Causes and How It Spreads, https://www.cdc.gov/chikungunya/causes-and-spread/index.html
2.Why dengue fever and other mosquito-borne illnesses are surging in Florida, By Cindy Krischer Goodman, https://www.miamiherald.com/news/local/article317280194.html
3.Chikungunya disease vaccine may become available at Florida pharmacies,https://www.gulfcoastnewsnow.com/article/chikungunya-disease-vaccine-pharmacy-florida/73782252
4.Florida local dengue cases top 150, 1st locally acquired chikungunya reported, Robert Herriman, https://outbreaknewstoday.substack.com/p/florida-local-dengue-cases-top-150-140
curated by Jonathan M. Metsch, Dr.P.H.
Clinical Professor of Environmental Medicine, Icahn School of Medicine at Mount Sinai