The Centers for Disease Control and Prevention (CDC) issued health advisories and travel alerts as dengue fever cases rise globally [1, 2].

The surge in cases highlights the vulnerability of tropical and subtropical regions to mosquito-borne illnesses as temperatures climb. Because the virus can lead to severe complications, health officials are urging travelers to take preventative measures to curb the spread.

Cases have increased in more than a dozen countries [1]. This trend includes tropical regions such as Hawaii [1, 3]. The rise in activity is attributed to warm weather and increased mosquito activity in these environments [1, 2].

Data regarding the impact within the U.S. shows a significant spike. There was a 359 percent increase in average annual cases of the virus in the U.S. in 2024 compared to the average from 2010 to 2023 [4].

While many infections are mild, the virus can be dangerous. About one in four infected people develop severe disease [1]. Some reports describe the virus as causing brain bleeding, though other health advisories focus on general prevention and travel alerts [1, 4].

Despite the increase in cases in Hawaii, some reports indicate that the risk to travelers remains relatively low [3]. The CDC continues to monitor the situation as summer warms up to prevent further transmission [2].

“About one in four infected people develop severe disease”

The discrepancy between the surge in case numbers and the 'low' risk assessment for travelers suggests that while the virus is spreading more widely due to climatic factors, the probability of an individual traveler contracting a severe form of the disease remains statistically small. However, the significant increase in U.S. cases compared to the previous decade indicates that the geographical footprint of the virus may be expanding.