CDC warns US travellers of growing Dengue threat. Here's what you need to know

The Centers for Disease Control and Prevention (CDC) has issued a warning about the increasing number of dengue fever cases among U.S. travellers, with expectations that the numbers will continue to rise throughout the year.

CDC cited a "record number" of cases reported among travellers in 2024, totalling 3,484 cases. This marked an 84 percent surge compared to the previous year.

"This trend is expected to continue with increased dengue activity in endemic areas in 2025," the CDC stated in its warning.

Dengue remains prevalent in certain regions of the States. The virus is being actively transmitted in U.S. territories, including Puerto Rico and the U.S. Virgin Islands, where outbreaks have been declared. Warmer temperatures during the spring and summer months create favourable conditions for the spread of the disease.

Over the past five years, dengue cases have surged worldwide, with the Americas being notably affected. Data from the World Health Organization (WHO) reveals that in 2024 alone, there were 7.6 million reported cases. Among these, 3.4 million were confirmed, over 16,000 were classified as severe, and more than 3,000 resulted in fatalities.

Puerto Rico has been grappling with a sustained dengue outbreak since early 2024. The island surpassed the outbreak threshold in February of that year, leading to the declaration of a public health emergency in March 2024, which remains in effect. Puerto Rico recorded 6,291 dengue cases in 2024, with more than half of the patients requiring hospitalization. Thirteen individuals lost their lives to the virus, according to the CDC data.

Similarly, the U.S. Virgin Islands declared an outbreak in August 2024, which also remains ongoing. Health authorities reported 208 cases in 2024 and an additional 30 cases in early 2025. The highest numbers of travel-related dengue infections in 2024 were reported in Florida, California, and New York.