Rising Dengue Cases in the US and Global Travel Concerns
The Centers for Disease Control and Prevention (CDC) has issued a global travel notice due to a significant increase in cases of dengue fever, a mosquito-borne illness that can lead to severe complications such as brain bleeds. This level 1 travel advisory was prompted by an unusual rise in dengue cases worldwide, with particular emphasis on 16 countries where travelers face a higher risk of infection.
The CDC’s latest report highlights a dramatic surge in dengue cases in the United States, with a 359 percent increase in average annual cases in 2024 compared to the 2010-2023 average. In 2024, a record 3,798 cases were reported, up from an average of 828 cases annually. Of these, 97 percent were linked to travel, while 3 percent were locally acquired.
Among the patients, 36 percent required hospitalization, and 3 percent of cases were classified as severe, resulting in six deaths. The peak of infections occurred between July and September, with Americans aged 50 to 59 making up the largest group of patients at 22 percent.
Travel-associated cases primarily originated from the Caribbean, accounting for 34 percent of all cases, including U.S. territories like Puerto Rico and the U.S. Virgin Islands. The CDC emphasized the urgent need for enhanced prevention strategies, improved clinical awareness, and targeted messaging for travelers heading to areas with ongoing dengue transmission.
Currently, the global dengue travel advisory includes countries such as Bangladesh, Bolivia, Colombia, Cook Islands, Guyana, Maldives, Mali, New Caledonia, Samoa, Somalia, Timor-Leste, and Vietnam. Dengue is prevalent in over 100 countries globally and poses a year-round threat to both travelers and local residents in high-risk regions.
A level 1 travel advisory urges Americans to take usual precautions due to the presence of an outbreak. This is the lowest level of travel alert, with level four being the most severe, advising against all travel.
Dengue fever is transmitted when a person is bitten by an infected Aedes aegypti mosquito. While many infections are asymptomatic, some patients may experience life-threatening internal bleeding, respiratory distress, and heart failure. It can also lead to shock and organ failure, particularly affecting the liver, brain, and heart. Patients may develop dengue shock syndrome, a condition characterized by severe bleeding leading to a rapid drop in blood pressure and shock.
Children under five, adults over 65, and pregnant women are considered most at risk from the virus. Although dengue was nearly eradicated in the U.S. in the 1970s, sporadic outbreaks have occurred, especially in warmer states like Florida and California. Most U.S. cases are linked to international travel.
According to the CDC report, 24 percent of cases stemmed from North America, and nearly 16 percent were from travel to Central America. The findings highlight the need for enhanced prevention strategies, clinical awareness, and tailored public health messaging for travelers to dengue-endemic areas.
The increase in travel-associated cases could elevate the risk of local transmission in parts of the U.S. that typically do not see dengue. The highest number of cases in 2024 were recorded in Florida, with 1,044 cases, followed by California (720), New York (338), and Texas (241).
Locally acquired dengue cases were reported in Florida, California, and Texas, with Florida recording 85 cases, California having 18, and Texas with two. Health officials note that about 40 to 80 percent of people infected with dengue do not show symptoms. When symptoms do appear, they usually manifest abruptly after five to seven days of infection.
Warning signs include a fever above 100°F (38°C), severe headache, pain behind the eyes, bone, joint, or muscle pain, and bleeding in the gums. Some patients may develop a rash several days after experiencing a high fever. In severe cases, symptoms may include severe abdominal pain, persistent vomiting, and lethargy.
There is no specific cure for dengue fever, and treatment focuses on managing symptoms and complications. Doctors recommend that patients with mild symptoms drink plenty of fluids and take Tylenol to alleviate pain. In severe cases, hospitalization may be necessary for supportive care, IV fluids, blood pressure monitoring, and blood transfusions if needed.
To protect against dengue, a three-dose vaccine is available, recommended for children aged nine to 16 years. The vaccine reduces the risk of symptomatic infection by approximately 80 percent.
