On June 25, 2024, the U.S. Centers for Disease Control and Prevention (CDC) issued a Health Alert Network (HAN) advisory referencing the increased risk of dengue virus (DENV) infections in the United States. From January 1- June 24, 2024, countries in Americas have reported more than 9.7 million DENV cases. This is the highest number ever in a single year. This includes DENV acquired within the U.S., namely Florida, Puerto Rico, and the US Virgin Islands, but also Texas, Arizona, California, and Hawaii.
With this global and domestic increase, the CDC recommends providers to take the following steps.
- Have increased suspicion of DENV among people with fever who have been in areas with frequent or continuous DENV transmission within 14 days before illness onset
Areas with Risk of Dengue | Dengue | CDC - Order appropriate diagnostic tests for acute DENV infection: reverse transcription polymerase chain reaction (RT-PCR) and IgM antibody tests, or non-structural protein 1 (NS1) antigen tests and IgM antibody tests
- Ensure timely reporting of DENV cases to public health authorities
- Promote mosquito bite prevention measures among people living in or visiting areas with frequent or continuous DENV transmission
Transmission
DENV is a vector-borne illness that spreads through the bites of infected Aedes species mosquitoes. Mosquitoes become infected with DENV when they bite an infected person. The infected mosquito can then spread DENV by biting other people.
A pregnant mother can pass DENV to their fetus during pregnancy. This may cause low birth weight, premature birth, and death of the fetus.
DENV may be found in breast milk. There is some evidence that suggests DENV may be spread through sexual contact.
Clinical Presentation
DENV may be in the differential diagnosis for patients with fever and recent travel (within 14 days before illness onset) to areas with frequent or continuous DENV transmission.
Approximately 25% of patients will show clinical signs of DENV. Symptoms may be non-specific and mild, with fever, aches and pains, nausea, vomiting, rash, and low white blood counts. Symptoms normally last for 2-7 days and most patients will recover after a week.
Approximately 5% of patients who get sick with Dengue will develop severe dengue. Severe symptoms may include abdominal tenderness, vomiting (> 3 times a day), bleeding from nose or gums, blood in vomit and stools, and extreme tiredness. Infants younger than 1 year of age, pregnant women, and adults greater than 65 years of age or with certain medical conditions are at higher risk to develop severe DENV. The risk of severe dengue is greater with a second infection.
Testing for DENV
DENV IgM antibody testing is recommended in combination with nucleic acid amplification tests (NAAT) or NS1 antigen tests during the first 7 days of illness. IgM levels are positive starting 4–5 days after onset of symptoms and continuing for approximately 12 weeks post symptom onset but may persist longer. Only one U.S. Food and Drug Administration-approved DENV IgM detection kit is commercially available. IgG testing is available in some clinical labs; however, this test should not be used to diagnose a patient with acute DENV because it does not distinguish between current and previous DENV infection. Please contact your local health department if guidance is needed regarding the preferred commercial or public health laboratory for DENV testing.
DENV is a nationally notifiable disease, please reported all cases to your local health department.
Treatment
There are no FDA-approved antivirals for DENV treatment. Treatment is supportive, and a fluid replacement strategy has been developed by the World Health Organization.
Prevention
A safe and effective DENV vaccine has been developed, but the manufacturer has discontinued production because of lack of demand. Vaccine administration will continue in highly endemic areas, such as Puerto Rico, until available doses expire in 2026. There are no vaccines recommended for travelers, or persons without a previous DENV infection when traveling to areas of known DENV spread.
Preventing mosquito bites is the best method to prevent DENV. Effective measures to prevent bites include reducing standing water, covering exposed skin with long-sleeved shirts and pants, and applying mosquito repellents on exposed skin and clothing.
The American Academy of Pediatrics provides guidance for how caregivers can choose a safe and effective insect repellent for their child: