A patient presents to the emergency department with fever, headache, nausea, and severe muscle pain after returning from a Caribbean cruise. A few years ago, dengue fever may not have been high on a nurse’s list of possible diagnoses. Today, it should be.

Cryoelectron microscopy renderings of mature dengue virions (DENV-1) and photo of an Aedes mosquito. (NIAID)

Dengue is the leading cause of febrile illness among travelers returning to the United States from endemic regions. According to the World Health Organization, about half of the world’s population is at risk for dengue, with an estimated 100 to 400 million infections occurring annually, although many cases likely go unreported because symptoms are mild or absent.

In a recent MMWR, 3,798 dengue cases were reported in the United States in 2024 representing a 359% increase compared to the annual average reported between 2010 and 2023. Nearly 97% of reported infections occurred in travelers, with many cases linked to destinations in the Caribbean, including Puerto Rico and the U.S. Virgin Islands. However, locally acquired cases were also identified in Florida, California, and Texas.

Cause and Challenges

Dengue, sometimes called “breakbone fever,” is caused by one of four related viruses and is spread primarily by infected Aedes aegypti and Aedes albopictus mosquitoes. Although dengue is most common in tropical and subtropical regions, these mosquito species are expanding their range in the United States, with nearly half of U.S. counties now home to mosquitoes capable of transmitting viruses.

One of the challenges of dengue is that its symptoms can resemble other viral illnesses. The CDC estimates that approximately one in four infected individuals develop symptoms. When illness occurs, patients may present with high fever, headache, nausea, vomiting, rash, and significant musculoskeletal pain. If symptoms occur, they usually occur 4 to 10 days after infection and last for 2 to 7 days.

While most patients recover, some develop severe dengue, which can be life-threatening. Warning signs often emerge as the fever begins to resolve and include severe abdominal pain, persistent vomiting, mucosal bleeding, lethargy or restlessness, liver enlargement, and fluid accumulation. Nurses should also be alert for early signs of shock, such as tachycardia, narrowing pulse pressure, hypotension, cool or clammy skin, delayed capillary refill, and decreased urine output. According to clinical guidance from CDC, laboratory findings include leukopenia, thrombocytopenia, hyponatremia, elevated aspartate aminotransferase (AST) and alanine aminotransferase (ALT), and a normal erythrocyte sedimentation rate (ESR). Prompt recognition and supportive care are critical because severe dengue can progress rapidly. Individuals with a second dengue infection are at greater risk for severe disease.

The Role of Nurses

Dengue can be life-threatening if not recognized early. Nurses play a critical role in identifying potential cases by obtaining a thorough travel history from patients presenting with unexplained febrile illness. Because most U.S. dengue cases are travel-associated, recent international travel and mosquito exposure can provide important clues that guide diagnostic testing and management. When dengue is suspected, CDC testing recommendations  include a nucleic acid amplification test (NAAT) and an IgM antibody test or an NS1 antigen test with an IgM antibody test to confirm the diagnosis. However, treatment should not be delayed while awaiting test results because early recognition and supportive care are critical to preventing disease progression.

Although there is no specific antiviral treatment for dengue, nurses can provide supportive care.  In general, pain can be managed with acetaminophen, but non-steroidal anti-inflammatory medicines such as ibuprofen and aspirin should be avoided due to the risk of bleeding. Although a dengue vaccine is licensed in the United States, its use is very limited. It is recommended only for certain children and adolescents ages 9 to 16 years living in dengue-endemic U.S. territories who have had a previous dengue infection. There is currently no recommended vaccine for U.S. adults.

Patient education is equally important. Individuals traveling to areas where dengue is common should be encouraged to prevent mosquito bites by using EPA-registered insect repellents, wearing long sleeves and pants, and eliminating standing water around homes and lodging areas. Since dengue can also be spread during pregnancy, education for women of childbearing age is imperative. Prevention and early detection remain the most effective strategies to avoid severe illness.

Moving Forward

The recent increase in dengue cases serves as a reminder that infectious disease threats continue to evolve. Although dengue is not yet a common diagnosis in most U.S. health care settings, rising case numbers and occasional local transmission underscore the need for diligence. Through careful assessment, patient education, and early recognition of symptoms, nurses can help identify cases promptly and reduce the impact of this growing public health concern.

Missy Travis, RN, MSN, CIC, FAPIC, is the founder of IP&C Consulting, LLC, a consulting business that supports infection preventionists, health care organizations, business owners, and professional sports teams in developing and sustaining effective infection prevention programs.