Key Links

Keylinks Right Menu 

Licensure Key Links

Keylinks Licensure

Increased Risk of Dengue Virus Infections in the United States.

The Louisiana Department of Health (LDH) is issuing this Health Alert Network (HAN) Health Advisory, modified from a CDC HAN, to inform clinicians and the public of an increased risk of dengue virus (DENV) infections in the United States in 2024. In 2024, 

 have reported a record-breaking number of dengue cases, exceeding the highest number ever recorded in a single year. Over 9 million cases have been reported between January 1 – June 24, 2024, twice as many as in all of 2023. In the United States, a higher-than-expected nu mber of dengue cases have been identified among U.S. travelers (745 cases), and Puerto Rico has already declared a public health emergency (1,498 cases). On average, Louisiana identifies 3 travel-associated dengue cases per year, but LDH has already investigated 6 travel-associated cases as of July 2, 2024. Cases are expected to continue to rise in Central and North America as the Northern Hemisphere enters peak mosquito season, and the number of travel-associated dengue cases are expected to continue to increase. The introduction of travel-associated cases also increases the risk for local disease transmission in Louisiana. In the setting of increased global and domestic incidence of dengue, healthcare providers are encouraged to take steps to prepare to identify, test, and manage dengue cases.

Additional Information for Healthcare Providers

 is the most common arboviral disease globally. It is caused by four distinct but closely related dengue viruses (DENV-1, -2, -3, and -4). DENVs are transmitted through bites of infected 

 species mosquito vectors, which are present throughout Louisiana and pose the risk for local disease transmission. Infection with one DENV generally induces life-long protection against infection from that specific DENV but on ly protects against other DENVs for several months to years. Six U.S. territories and freely associated states are classified as 

areas with frequent or continuous dengue transmission

: Puerto Rico, American Samoa, the U.S. Virgin Islands, the Federated States of Micronesia, the Republic of Marshall Islands, and the Republic of Palau. In the rest of the United States, local transmission of DENV has been limited, with sporadic cases or small outbreaks in Florida, Hawaii, and Texas. However, confirmed local DENV transmission has also been reported by Arizona and California over the past two years.

Approximately one in four DENV infections are symptomatic and can be mild or severe. Symptoms begin after an incubation period of 5–7 days (range 3–10 days) and present as fever accompanied by 

such as nausea, vomiting, rash, muscle aches, joint pain, bone pain, pain behind the eyes, headache, or low white blood cell counts. 

 are specific clinical findings that predict progression to severe disease. Warning signs include abdominal pain or tenderness, persistent vomiting, clinical fluid accumulation (e.g., ascites, pleural effusion), mucosal bleeding, lethargy or restlessness, progressive increase of hematocrit, or liver enlargement >2cm. Severe disease, with associated severe bleeding, shock or respiratory distress caused by plasma leakage, or end-organ impairment, develops in 1 in 20 people with symptomatic dengue. Infants aged ≤1 year, pregnant people, adults aged ≥65 years, and people with 

 are at increased risk of severe dengue. Although a second DENV infection (i.e., with a different DENV from the first infection) carries a higher risk of severe disease than a first, third, or fourth infection, any infection can lead to severe disease.

 with both molecular and serologic diagnostic tests. All patients with suspected DENV infection should be test ed with RT-PCR (i.e., a nucleic acid amplification test (NAAT)) or a NS1 antigen test, and also with IgM antibody test to confirm DENV infection. These tests can be considered regardless of the symptom onset date, although the test sensitivity of RT-PCR and NS1 antigen tests decrease after the first 7 days. IgG detection by enzyme-linked immunosorbent assay (ELISA) in a single serum sample should not be used to diagnose a patient with acute dengue because it does not distinguish between current and previous DENV infection.

There are no antiviral medications approved to treat dengue. Treatment is supportive and requires careful volume management. Appropriate 

 remain the most effective interventions to reduce dengue morbidity and mortality. Expectant management of patients at high risk for severe disease and rapid initiation of a standardized fluid replacement strategy recommended by the World Health Organization (WHO) can decrease mortality from 13% to <1%.

LDH will continue to work with healthcare providers and healthcare systems to identify and detect dengue cases in Louisiana. In addition to routine activities, LDH will be performing enhanced monitoring for dengue in Louisiana, including analyzing emergency department visit reports and requesting confirmatory testing for clinically compatible cases. This enhanced monitoring is meant to assist with case detection in order to initiate mitigation efforts to prevent disease transmission within the state.

Webinar: What Clinicians Need to Know about Dengue in the United States | CDC