CDC Issues Health Alert on Ongoing Risk of Dengue Virus Infections

On March 18, CDC issued a Health Alert Network (HAN) update regarding the ongoing risk of dengue virus (DENV) infections in the U.S. and globally. Dengue activity remains high in many regions, particularly in the Americas, with significant increases in cases in 2024 and 2025. The CDC urges healthcare providers, public health departments, and the public to continue preventive measures, detection, and response to dengue.

Key updates include:

• Dengue transmission is high in the Americas, especially in Puerto Rico and the U.S. Virgin Islands.
• CDC recommends using RT-PCR tests for diagnosing dengue when it's the most likely cause.
• New resources for public health professionals are available, including job aid and guidance for investigating dengue cases in non-endemic areas.
• Dengue is caused by four viruses, and while immunity to one virus lasts, infections with different serotypes can lead to severe illness, particularly in vulnerable groups like infants, pregnant women, and the elderly.
• The Americas saw a rise in cases, with over 760,000 reported in 2025 alone.

In the U.S., dengue cases are rising, with significant travel-associated cases in Florida, California, and New York. Puerto Rico and the U.S. Virgin Islands have ongoing outbreaks. Healthcare providers should maintain a high suspicion for dengue, especially in patients with a history of travel to endemic areas. Testing with RT-PCR and other diagnostics is essential.

Public health departments are advised to investigate and respond to dengue cases and share prevention guidance with the public, emphasizing mosquito bite prevention during travel and post-travel.

CDC says it will continue to support efforts to detect, diagnose, and control dengue cases as the risk remains high, particularly with increased travel during peak seasons.