Florida is currently experiencing its largest dengue outbreak in the continental United States in several decades, with state health officials reporting more than 250 locally transmitted cases so far this year. The majority of infections have been identified in Hillsborough County, which includes the city of Tampa. The outbreak, first detected in July, is poised to surpass previous records, including a 2015-2016 outbreak in Hawaii that logged 264 locally acquired cases over six months.
Dengue, a viral disease transmitted by mosquitoes, often results in flu-like symptoms, severe joint and muscle pain, and in some cases, more serious complications such as bleeding and shock. The illness is sometimes called “breakbone fever” due to the intense pain it can cause. This year, Florida has reported one dengue-related death: an elderly Tampa woman who passed away in early September.
Experts note that the dengue virus has four distinct types—1 through 4. Infection with one type generally confers lifelong immunity to that strain, but subsequent infections with different types can exacerbate the severity of the illness. This complexity has hindered the development of an effective vaccine. Dawn Wesson, a Tulane University researcher specializing in mosquito-borne diseases, highlighted that most residents in the Tampa area lack prior immunity to dengue, increasing their susceptibility.
The mosquitoes that spread dengue have traditionally thrived in southern regions like Miami but have expanded their range in recent years due in part to climate change and rising temperatures. Historically, dengue cases in the continental US were mostly linked to travelers returning from affected areas, particularly Puerto Rico. However, locally transmitted cases in Florida this year have exceeded travel-associated infections, with 252 local cases compared to 245 travel-related ones. At least 13 cases in Hillsborough County were diagnosed in travelers.
Local health authorities in Hillsborough and neighboring counties have declared public health emergencies and implemented intensive mosquito control efforts, including around-the-clock spraying and eliminating standing water where mosquitoes breed. Public health officials emphasize preventive measures such as using EPA-approved insect repellents, wearing protective clothing, and reducing mosquito habitats to curb the spread of the disease.
The Centers for Disease Control and Prevention (CDC) has provided $800,000 in support to state health officials but has not deployed disease investigators on the ground, as Florida has not formally requested federal assistance beyond financial aid.
Globally, dengue remains a significant public health challenge, with over 2.2 million cases and nearly 1,200 deaths reported this year according to the World Health Organization. Within the US, nearly 1,900 locally acquired dengue cases have been confirmed, mostly in Puerto Rico.
Experts caution that given ongoing climate shifts and persistent mosquito populations, dengue outbreaks may become increasingly common in Florida and other parts of the continental United States. “There’s a good chance that this is the new normal,” Wesson said.