JONATHAN M. METSCH, Dr.P.H. – Tracking Emerging Public Health Challenges – November 6, 2026 – DENGUE
“Infected mosquitoes spread dengue to people. Symptoms include high fever, headache and body pain, which is how it got the nickname “breakbone fever.”
People typically contract it while traveling through a continent where the virus is always present, like South America, Asia or Africa.
But this year, folks who got infected during their worldly adventures brought it back to the U.S., passing it on to the mosquitoes here.
Now, nearly 500 cases that are not travel-related have been reported in Florida.
“I have not seen anything like this. … It is very much unprecedented,” said Eva Buckner, an insect scientist at the University of Florida.
The largest outbreak of locally acquired dengue in the continental U.S. in nearly a century is happening in Florida, with Hillsborough County at the epicenter. The mosquito-borne virus even caused the death of an 80-year-old Tampa woman in September.
The spread was triggered by multiple factors.
Why Florida and Hillsborough?
Bucker said dengue has been recently very active globally.
“Which allows multiple travel cases to occur in Florida,” she said.
Plus, the state already has the type of mosquito that can carry dengue: Aedes aegypti. And then there was a long drought this year.
“Aedes aegypti has drought-resistant eggs, and so it allowed some of the eggs to build up in the environment,” Buckner said.
So, when it finally rained in June, all those eggs hatched simultaneously — just in time for a hot, humid summer, in which these mosquitoes thrive.
Cases spiked in the Tampa area because officials weren’t prepared to fight this tropical disease like they already do in more southern Florida counties like Miami-Dade or Lee.”
“Infectious disease researchers are documenting a global trend linking warming temperatures and the spread of dengue.” (1)
“Dengue isn’t the only mosquito-transmitted disease that has popped up this year in Florida, although those have been in far fewer numbers than dengue: West Nile Virus, Chikungunya and Eastern Equine Encephalitis. Another case of West Nile Virus was reported in Sarasota County, bringing the 2026 total to seven cases, although two were asymptomatic.” (2)
“Dengue is a year-round risk in tropical and subtropical areas of Central and South America, including Brazil and Mexico; Asia, including the Philippines; the Middle East; Africa; and several Pacific islands, including American Samoa, the Federated States of Micronesia, the Republic of the Marshall Islands and the Republic of Palau.
Many popular tourist destinations in the Caribbean, including Puerto Rico, are also affected. Some countries are reporting higher-than-usual numbers of dengue cases, including Bangladesh, Bolivia, Cambodia, Costa Rica, Cuba, Ecuador, Kenya, Malaysia, Maldives, the Marshall Islands, Panama, Sri Lanka, Vanuatu and Vietnam.
Travelers should review current, country-specific travel information for guidance on dengue risk and prevention measures at least four to six weeks before traveling.
For current travel health information and guidance, visit the Centers for Disease Control and Prevention (CDC) travel website.
Anyone planning to travel to or who has recently visited an area with dengue risk may be at risk for infection. The CDC advises travelers to take standard precautions when visiting such areas. These include using an Environmental Protection Agency-registered insect repellent, wearing long-sleeved shirts and long pants outdoors, as well as sleeping in air-conditioned rooms, rooms with window screens or under insecticide-treated bed nets.
Travelers returning from areas with dengue risk should take precautions to prevent mosquito bites for three weeks. If dengue symptoms develop within two weeks of returning, travelers should seek medical evaluation.”
“Mosquitoes need only small amounts of standing water to breed. Common breeding sites include buckets, water-catching plants such as bromeliads, small containers, planters, rain barrels and even cups left outside. Prevent standing water from collecting around homes and workplaces by emptying containers and other items where mosquitoes can lay eggs.” (3)
1.How Florida became the epicenter of localized U.S. dengue cases and what role climate played, By Jessica Meszaros https://www.sun-sentinel.com/2026/11/06/how-florida-became-the-epicenter-of-localized-u-s-dengue-cases-and-what-role-climate-played/
2. Florida dengue cases surge to 485 in largest outbreak in US in decades, by Cheryl McCloud and C. A. Bridges, https://www.heraldtribune.com/story/news/state/2026/10/30/florida-dengue-cases-surge/92477372007/
3.Dept. of Health confirms 11th travel-related dengue case in Hawaii, https://www.hawaiinewsnow.com/2026/11/05/dept-health-confirms-11th-travel-related-dengue-case-hawaii/
curated by Jonathan M. Metsch, Dr.P.H.
Clinical Professor of Environmental Medicine, Icahn School of Medicine at Mount Sinai