Posted June 28, 2024. Past health advisories and alerts are archived for historical purposes and are not maintained or updated.
The Centers for Disease Control and Prevention (CDC) is issuing this Health Alert Network (HAN) Health Advisory to notify healthcare providers and the public of an increased risk of dengue virus (DENV) infections in the United States. Global incidence of dengue in 2024 has been the highest on record ; many countries are reporting higher-than-usual dengue case numbers. In 2024, countries in the Americas have reported a record-breaking number of dengue cases. From January 1 – June 24, 2024, countries in the Americas reported more than 9.7 million dengue cases, twice as many as in all of 2023 (4.6 million cases). In the United States, Puerto Rico has declared a public health emergency (1,498 cases) and a higher-than-expected number of dengue cases have been identified among U.S. travelers (745 cases). In the setting of increased global and domestic incidence of dengue, healthcare providers should take steps including:
Dengue 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 Aedes species mosquito vectors. Infection with one DENV generally induces life-long protection against infection from that specific DENV but only protects against other DENVs for several months to years. Dengue is a nationally notifiable disease in the United States.
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 non-specific signs and symptoms such as nausea, vomiting, rash, muscle aches, joint pain, bone pain, pain behind the eyes, headache, or low white blood cell counts. Warning signs that predict progression to severe disease 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 certain medical conditions 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.
Patients with symptoms compatible with dengue can be tested with both molecular and serologic diagnostic tests. All patients with suspected DENV infection should be tested 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. U.S. Food and Drug Administration (FDA)-approved testing is available at public health laboratories and some commercial laboratories. State, tribal, territorial, and local health departments, and CDC can offer additional testing guidance.
There are no antiviral medications approved to treat dengue. Treatment is supportive and requires careful volume management. Appropriate triage, management, and follow-up 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%. In June 2021, the Advisory Committee of Immunization Practices recommended a dengue vaccine, Dengvaxia, for children aged 9–16 years with laboratory confirmation of previous DENV infection and living in areas with frequent or continuous dengue transmission such as Puerto Rico. While the vaccine is considered safe and effective, the manufacturer (Sanofi Pasteur, Inc., Paris France) has discontinued production citing a lack of demand. Vaccine administration will continue in Puerto Rico until available doses expire in 2026.There are no vaccines recommended for travelers, adults, or persons without a previous DENV infection.
To report suspected cases, or for any other questions, please contact Spokane Regional Health District at CDEpi@srhd.org, 509-324-1442 with questions, or 509-324-1449 for reporting. Reports could also be faxed to 509-324-3623.
Travel Vaccines:
For patients who need vaccines for travel to other countries, here are some options in the Spokane area (this list is not all inclusive or an endorsement):
