The ‘Wildly Unusual’ Deadly Outbreak Spreading Across The U.S.

Three Florida counties, including Hillsborough, have declared local states of emergency as locally acquired cases of dengue fever continue to rise.

The Florida Department of Health has reported 190 locally acquired cases so far in 2026 across six counties, 170 of them in Hillsborough. One person has died.

“This is wildly unusual for us,” Chris Wilkerson, a spokesperson for Hillsborough County, told the AP about the outbreak, per ABC News.

Officials have said the weather is likely a factor, as heavy rains have left standing water, making it easier for Aedes aegypti mosquitoes that carry the virus to breed more quickly. Residents have been warned to check their homes and properties regularly and dispose of standing water to slow reproduction.

Those diagnosed with the virus have also been warned to isolate themselves, because if they are bitten by a mosquito while infected, that mosquito can spread the disease to others. Dengue fever cannot be transmitted from person to person like a cold or flu, but requires the mosquito vector to pass from one person to another.

The mosquito-borne virus, also known as “breakbone fever” because of the severe pain some sufferers feel in their bones and joints, is typically contracted in tropical regions — and most cases documented in the United States have traditionally been diagnosed in patients who had recently traveled outside the country.

Aedes aegypti mosquitoes are common in Florida and across the southern United States, and can also carry several other diseases like the Zika virus and Yellow fever — and they’re considered to present a higher risk because, unlike many other species of mosquitoes, they are active during the day.

Recent testing of mosquitoes around the affected area has been negative for the virus — and suggests that females carrying the virus are not passing it to their offspring — which has officials hopeful that the outbreak could soon resolve on its own. But the overall threat, they say, is not likely to go away.

“I do think it’s going to be somewhat the new normal,” Michael von Fricken, a University of Florida associate professor of environmental and global health, told The Associated Press.

In addition to severe bone pain, the virus can cause a sudden high fever, headaches, rash, and nausea. Patients are warned to seek immediate medical attention if they experience confusion, extreme fatigue, or restlessness.