Map Shows Surging Dengue Fever Cases as Spring Break Warning Issued

A Newsweek map shows where cases of dengue fever have been seen in the United States as an alert has been issued for the upcoming peak season during spring and summer travel.

Why It Matters

Dengue fever is a viral infection transmitted by the Aedes aegypti mosquito, which bites during the day. In most cases, it causes sudden high fever, severe headache, pain in muscles, joints and bones, a skin rash, nausea, vomiting, fatigue and weakness.

Infections can be particularly severe in pregnant women, the elderly, people with existing health conditions and people who have previously had dengue infections.

Cases have increased "substantially" in the last five years, the Centers for Disease Control and Prevention (CDC) said, with 13 million cases and 8,200 deaths reported in 2024.

What To Know

Puerto Rico has seen the highest number of cases this year by far, with 1,012 reported, according to the CDC.

"In Puerto Rico, reported dengue cases have remained above the outbreak threshold since February 2024," the CDC said. "A public health emergency was declared in March 2024 and remains in effect."

Puerto Rico is followed by the U.S. Virgin Islands (40), where a dengue outbreak was declared in August 2024 and remains in effect.

Next are Florida (45), California (10), New York (six), Arizona (five), Hawaii and Massachusetts (four), North Carolina and Pennsylvania (three).

Georgia, Idaho, Illinois, Kansas, Maryland, Ohio, Virginia and Wisconsin have all had two cases reported, while Alaska, Arkansas, Washington, D.C., Delaware, Iowa, Indiana, Kentucky, New Hampshire, South Carolina and Washington state have had one case reported.

The CDC issued a health alert this month that said: "Dengue virus transmission remains high in the Americas region, including in the U.S. territories of Puerto Rico and the U.S. Virgin Islands. Spring and summer travel coincide with the peak season for dengue in many countries, increasing the risk of both travel-associated and locally acquired cases in the United States."

What People Are Saying

The Centers for Disease Control and Prevention: "Dengue activity remains high in some parts of the United States and globally, with many countries reporting higher-than-usual numbers of dengue cases in 2024 and 2025. Healthcare providers, public health departments, and the public are urged to continue to take steps to prevent, detect, diagnose, and respond to dengue."

What Happens Next

The CDC said it will continue to support public health partners in detection, surveillance and outreach to respond to the ongoing threat of dengue in the United States. It has issued several recommendations for health care providers, departments and the public.