What You Need To Know
The Centers for Disease Control and Prevention (CDC) issued a Health Advisory on June 25th to notify healthcare providers, public health authorities and the public of an increased risk of dengue virus (DENV) infections in the United States due to ongoing outbreaks in the Americas.
A higher-than-expected number of cases has been identified among US travelers, including in New Jersey, where 42 travel-associated cases of dengue have been reported in 2024, compared to 10 cases at this time last year. No locally acquired cases of DENV have been reported in NJ.
Almost all dengue cases reported in the US are travel-associated, but rare locally acquired cases have been reported in Florida, Texas, Hawaii, Arizona, and California. Dengue is transmitted primarily through the bites of infected Aedes species mosquitoes. Ae. aegypti mosquitoes are the primary vector for DENV transmission and are NOT established in NJ. Ae. albopictus mosquitoes are present in NJ but are less efficient at transmitting DENV. An outbreak of locally acquired dengue in NJ is unlikely, although isolated cases are possible.
People serve as the reservoir for DENV. It is important for persons with an acute dengue infection and for travelers returning from countries with DENV transmission to prevent mosquito bites after returning to NJ, to prevent transmission of the virus to local mosquitoes, who could then bite and infect another person in NJ.
It is important that clinicians consider dengue in the differential diagnosis of returning travelers with fever, and that clinicians and public health providers take steps to prevent dengue from spreading via our local mosquitoes.
Dengue is caused by four distinct but closely related dengue viruses (DENV-1, -2, -3, and -4) and is transmitted by the bite of an infected mosquito. Infection with one DENV generally induces life-long protection against infection from that specific virus but only protects against other DENVs for several months to years.
About 1 in 4 dengue infections are symptomatic and 1 in 20 progresses to severe dengue, which can be life threatening. Appropriate triage, management, and follow-up remain the most effective interventions to reduce dengue morbidity and mortality.
Testing for dengue is available through commercial laboratories. Patients with suspected DENV infection should be tested with an RT-PCR or a NS1 antigen test AND with an IgM antibody test. 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 antibody tests in a single serum sample should NOT be used to diagnose a patient with acute dengue.
Action Items:
- Healthcare providers
- Maintain a high suspicion for DENV for patients with fever and travel to areas with DENV transmission in the 14 days before illness onset.
- Order appropriate tests for suspected dengue infection:
- RT-PCR AND IgM antibody test OR
- NS1 antigen AND IgM antibody test
- If commercial testing is not feasible (i.e., uninsured patients), testing is available at the NJ Public Health and Environmental Laboratories (PHEL).
- Providers should complete the Arboviral Testing Request worksheet and send via encrypted e-mail to CDSVectorTeam@doh.nj.gov.
- Know the warning signs of severe dengue infection and recognize the critical phase. Hospitalize patients with severe dengue or any warning sign of progression to severe dengue and follow CDC/WHO protocols for IV fluid management.
- Obtain a thorough travel history on patients with suspected DENV infection and report dengue cases and recent travel history to the local health department.
- Consider locally acquired dengue for patients with highly compatible signs and symptoms (fever, thrombocytopenia, leukopenia, aches, pains, rash). Report patients who test positive for DENV without recent travel to an area with DENV transmission immediately to the local health department.
- Local Health Departments
- Investigate dengue reports promptly. Investigations should begin within 2 days of notification and critical details (including travel history) should be entered into CDRSS within 5 days.
- Notify the CDS Vector-borne Disease Team via email (CDSVectorTeam@doh.nj.gov) if the case does not have a recent travel history to an area with DENV transmission.
- Notify your county mosquito agency of the positive case so that timely mosquito surveillance and control efforts can be performed.
- Advise dengue cases to prevent mosquito bites for 1 week after symptom onset.
- Educate travelers to areas with dengue transmission to prevent mosquito bites while traveling and for 3 weeks after returning to NJ.
Contact Information:
- The CDS Vector-borne Disease Team, CDSVectorTeam@doh.nj.gov