The US Centers for Disease Control and Prevention (CDC) today issued a Health Alert Network notice to healthcare providers and the public about the ongoing risk of dengue virus infections, with levels remaining high in some US territories and surges still under way in other countries, especially in the Americas region.

In Puerto Rico, a dengue emergency declared in March 2024 remains in effect, and cases this year are up 113% compared to this time a year ago. The US Virgin Islands declared an outbreak in August 2024, and cases continue, with 30 local cases already reported this year.
A substantial rise in global dengue cases over the past 5 years, plus record levels in the Americas, led to a record number of travel-related cases in the United States in 2024, up 84% from the previous year. Three US states reported local dengue cases last year, and the CDC said it’s possible that local transmission could rise in the continental United States in areas that have mosquitoes that can carry the virus.
“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 group said.
Rising portions of dengue serotype 4 cases in travelers
The CDC said all four dengue serotypes were reported in US travelers in 2024, but it added that the proportion of dengue serotype 4 has been on the rise in recent months. It urged healthcare providers to use the CDC’s DENV-1-2 real-time reverse transcriptase polymerase chain reaction (RT-PCR) test when dengue is the most likely diagnosis and urged them to use a new job aid on reviewing medical records for case investigations.