### CDC Warns of Increased Dengue Fever Risk in the U.S.
The Centers for Disease Control and Prevention (CDC) has issued a [warning](https://emergency.cdc.gov/han/2024/han00511.asp) about an increased risk of [dengue fever](https://www.mayoclinic.org/diseases-conditions/dengue-fever/symptoms-causes/syc-20353078) in the United States.
Dengue fever is a potentially life-threatening viral infection transmitted by infected mosquitoes. The CDC’s health alert highlights an unexpected surge in dengue fever cases within the U.S. Puerto Rico has declared a health emergency with 1,498 reported cases. Among U.S. travelers, 745 cases were identified as of June 24 this year.
This U.S. health alert coincides with a global increase in dengue fever outbreaks, with Latin American countries reporting 9.7 million cases since the start of 2024, more than double the 4.6 million cases recorded in all of 2023.
“Four different subtypes of the virus can cause infections in humans,” says [Dr. Stacey Rizza](https://www.mayoclinic.org/biographies/rizza-stacey-a-m-d/bio-20054180?mc_id=us&utm_source=newsnetwork&utm_medium=l&utm_content=content&utm_campaign=mayoclinic&geo=national&placementsite=enterprise&cauid=100721), a Mayo Clinic infectious diseases specialist. “Dengue transmission is prevalent in areas with significant mosquito populations and warm climates.”
**[Watch: Dr. Stacey Rizza explains dengue fever](https://youtu.be/gBektU9hSwU)**
**Journalists:** Broadcast-quality sound bites with Dr. Rizza are available for download at the end of this post. Please credit: “Mayo Clinic News Network.” Name super/CG: Stacey Rizza, M.D./Infectious Diseases/Mayo Clinic.
Approximately half of the world’s population lives in areas susceptible to dengue fever, particularly in hot and humid tropical and subtropical climates.
“This is why dengue fever is common in regions such as Southeast Asia, South America, the Caribbean, and parts of the southern U.S., including Florida and Louisiana,” says Dr. Rizza.
The primary vector for dengue fever is the Aedes aegypti mosquito, which bites both during the day and night. About one in four people infected with the virus will experience symptoms ranging from mild to severe.
