Rising Cases Prompt Warnings Ahead of Summer Travel Season

Federal health officials are alerting the public to an increase in dengue fever cases this year, coinciding with the upcoming summer travel season. The Centers for Disease Control and Prevention (CDC) has issued a warning regarding the ongoing transmission of the viral infection in the United States and its territories. Residents of California and Florida are advised to be particularly vigilant, as these states typically experience the highest number of cases annually.

Dengue fever, a potentially serious illness, is transmitted through the bite of infected mosquitoes. While many individuals recover within a week, severe cases can lead to internal bleeding and, in approximately one in twenty cases, death. Those at higher risk of severe illness include pregnant women, adults over 65, individuals with certain medical conditions, infants, and those with previous dengue infections. Common symptoms include fever, rash, and vomiting, typically appearing within two weeks of a bite. Other symptoms may include bleeding from the nose or gums, abdominal pain, and fatigue or restlessness.

Outbreaks of dengue fever have been declared in the U.S. Virgin Islands and Puerto Rico within the past year. A public health emergency remains in effect in Puerto Rico, declared last March. In the continental U.S., Florida has reported the majority of locally acquired cases in 2024, followed by California and Texas. The highest numbers of travel-associated cases in 2024 were reported in Florida, California, and New York.

The CDC anticipates that epidemics in the Americas will contribute to an increase in both travel-associated cases and the potential for local transmission within the continental U.S. A significant rise in dengue cases among U.S. travelers has already been observed, with an 84% increase compared to the previous year. This trend is expected to continue into 2025, with increased dengue activity in endemic areas.

Globally, dengue cases have surged in the last five years, with the most significant increases occurring in the Americas. Climate change is linked to the rise in cases, as warmer temperatures and more humid climates create more favorable environments for the mosquitoes that carry the virus. Fast-warming urban areas are particularly affected.

While there is no specific treatment for dengue fever, the primary method of staying safe is to avoid exposure. The CDC recommends taking precautions to prevent mosquito bites during travel, especially in areas with frequent dengue transmission. Additionally, it is advised to continue these preventative measures for three weeks after travel to avoid potentially spreading the virus.