An urgent warning has been issued for U.S. travelers heading to Puerto Rico this spring break.
The Centers for Disease Control and Prevention issued a health advisory on March 18 to address the ongoing rise of dengue virus infections, with activity remaining “high” in some parts of the U.S. and globally.
Dengue is “a viral infection that spreads from mosquitoes to people,” per the World Health Organization, and it is “more common in tropical and subtropical climates.”
According to the CDC’s advisory, transmission of dengue virus, also known as dengue fever, is high in the Americas region, which includes two popular travel spots: the U.S. territories of Puerto Rico and the 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,” the health organization noted.
The CDC marked the advisory about dengue as a level 1 health alert, meaning it “conveys the highest level of importance about a public health incident.”
The CDC offered sound advice for travelers heading to high-transmission areas.
“In addition, take steps to prevent mosquito bites for three weeks after travel to avoid possibly spreading the virus to others if you are in an area where mosquitoes are active,” the CDC wrote in the health alert. “These activities will also lower the risk for other vector-borne diseases.”
In Puerto Rico, the “reported dengue cases have remained above the outbreak threshold since February 2024,” per CDC. There was a public health emergency declared in March 2024 and has remained since. Throughout 2024, there were also 6,291 cases of dengue reported in Puerto Rico, with more than 52 percent of them requiring hospitalization.
So far, there have been 936 cases in Puerto Rico this year as of March 7, which is a 113 percent increase from how many cases there were this time last year.
In the U.S. Virgin Islands, a dengue outbreak was declared in August 2024. The emergency alert remains in effect, with 208 cases identified in 2024 and 30 identified in 2025, as of March 7.
Meanwhile, there were 91 locally acquired cases of dengue reported in Florida in 2024. Among U.S. travelers, there were 3,483 cases identified in 2024, which is an 84 percent increase compared to the previous year.
Around the world, the concerns about dengue are even greater, with about four billion people living in areas with a risk of dengue, according to the CDC.
Dengue is a common disease in the Americas, Africa, the Middle East, Asia, and the Pacific Islands. Outbreaks are frequently reported in other tourist destinations, such as the Caribbean, Southeast Asia and the Pacific Islands.
The most common symptom is fever, followed by aches and pains throughout the body, vomiting, and a rash. Symptoms usually last from two to seven days, per the CDC. However, symptoms could become severe within a few hours, making the condition a medical emergency.
Nearly one in 20 people who get the infection “will develop severe dengue,” which “can result in shock, internal bleeding, and death.”
