The Rise of Dengue Cases in the United States

Dengue poses a year-round risk in many parts of the world, with outbreaks occurring every 2–5 years. Recently, some countries have reported increased cases of the disease, which spreads through mosquito bites. Travelers to these high-risk areas are advised to protect themselves by using EPA-registered insect repellent, wearing protective clothing, and staying in air-conditioned or screened accommodations to prevent mosquito bites.¹

The CDC recommends that travelers take precautions against the Dengue virus (DENV). They suggest applying an EPA-approved insect repellent, wearing long-sleeved shirts and pants outdoors, and ensuring accommodations are air-conditioned or equipped with window screens, or sleeping under a bed net treated with insecticide.²

The DENV vaccine, Dengvaxia, is not approved for use in US travelers visiting but not residing in dengue-endemic areas. Annually, up to 400 million people contract DENV, resulting in illness in about 100 million cases, with severe dengue causing approximately 40,000 deaths. Dengvaxia is authorized for children aged 9 to 16 who have previously had a laboratory-confirmed dengue infection and live in regions where dengue is prevalent, including certain US territories and associated states.²

According to the CDC, “health effects from dengue include fever, headache, nausea, vomiting, rash, muscle and joint pain, and minor bleeding. Dengue can become severe within a few hours. Severe dengue is a medical emergency, usually requiring hospitalization. In severe cases, health effects can include hemorrhage (uncontrolled bleeding), shock (low blood pressure), organ failure, and death.”²

Surveillance data have limitations: under-reporting is common, as healthcare providers may miss cases or delay reporting. Mild illnesses are often underreported compared to severe ones due to varying disease awareness and healthcare-seeking behavior. Geographic analyses may be skewed since data are grouped by residence, not exposure location. Delays in reporting to the CDC and varying state publication schedules complicate data interpretation and response efforts.³

These recently reported DENV cases spread primarily through mosquito bites. Travelers to high-risk areas should follow CDC-recommended precautions and stay vigilant for symptoms, as severe cases can lead to critical health complications requiring prompt medical attention.

References

1. CDC. Global Dengue. Travelers Health. Published June 25, 2024. Accessed July 11, 2024. https://wwwnc.cdc.gov/travel/notices/level1/dengue-global

2. Abene S. CDC Issues Crucial Guidance for Travelers to Dengue-Endemic Regions. Contagion. Published January 31, 2024. Accessed July 11, 2024. https://www.contagionlive.com/view/cdc-issues-crucial-guidance-for-travelers-to-dengue-endemic-regions

3. CDC. Current Year Data (2024). Dengue. Published July 2, 2024. Accessed July 11, 2024. https://www.cdc.gov/dengue/data-research/facts-stats/current-data.html