5 Things to Know About Dengue

Dengue is the most common arboviral disease globally and is caused by four distinct but closely related dengue viruses (DENV-1, -2, -3, and -4), also called serotypes. DENVs are transmitted by the bites of infected Aedes species mosquitoes. Dengue is endemic in six US territories and freely associated states, including Puerto Rico, American Samoa, US Virgin Islands, the Federated States of Micronesia, the Republic of Marshall Islands, and the Republic of Palau. In other areas of the United States, locally acquired dengue cases have been detected in Florida, Texas, Hawaii, Arizona, California in recent years. In March 2024, public health authorities in Puerto Rico declared a dengue outbreak because more than 1000 cases were reported during the traditionally low dengue season. Epidemics in Puerto Rico and other areas with dengue risk could increase travel-associated cases and limited local transmission in the continental United States and Hawaii. Healthcare providers should be prepared to recognize, diagnose, manage, and report dengue cases.
From January 1 to July 16, 2024, countries in the Americas reported more than 10 million dengue cases to the Pan American Health Organization. In the United States, public health authorities declared a dengue outbreak in Puerto Rico and reported 827 cases in US travelers as of July 2; this is three times higher than the average number of cases for the same time period in recent years. 
Have increased suspicion for dengue among people with fever and recent travel to dengue-endemic areas.
Common symptoms of dengue include fever, myalgias/arthralgias including retroorbital pain, nausea/vomiting, and rash.
Promote mosquito bite prevention measures during and after travel in patients visiting areas where dengue is endemic.
Severe disease develops in 1 in 20 people with symptomatic dengue and can lead to shock within hours.
Knowing the warning signs of severe dengue can save lives. Dengue warning signs include intense abdominal pain or tenderness, persistent vomiting, clinical fluid accumulation, mucosal bleeding, lethargy or restlessness, liver enlargement, and hemoconcentration.
Patients with warning signs should be monitored closely because they can be more likely to progress to severe disease. Severe dengue can result in severe bleeding, shock caused by plasma leakage, or end-organ impairment.
People at higher risk for severe disease include pregnant people, infants < 1 year, adults aged 65 years or older, and those with underlying conditions including diabetes, asthma, hypertension, chronic kidney disease, chronic liver disease, peptic ulcer disease and other gastritis and obesity, and conditions requiring anticoagulation medications.
Recognize the critical phase of dengue. The critical phase begins when fever starts to decline and lasts for 24-48 hours. During this phase, some patients may deteriorate within hours without appropriate intravenous fluid management and require close monitoring.
All patients with suspected DENV infection should be tested with reverse-transcriptase polymerase chain reaction (RT-PCR) assay and immunoglobulin (Ig)M antibody tests or dengue NS1 antigen and IgM antibody tests to confirm acute dengue infection. Laboratory testing is most sensitive when performed within the first 7 days after illness onset. These tests can be considered regardless of the symptom onset date, although the sensitivity of RT-PCR and NS1 antigen tests decrease after the first week. IgG detection by enzyme-linked immunosorbent assay in a single serum sample can detect previous infection with a dengue virus but cannot be used to diagnose a patient with dengue. US Food and Drug Administration–approved testing is available at public health laboratories and at some commercial laboratories. Contact your state, territorial, tribal, or local health department or CDC for additional testing guidance. 
Dengue is a nationally notifiable disease in the United States. Notify your state, local, tribal, or territorial health department of suspected dengue cases, who can then take actions to reduce the risk for additional DENV transmission in the area. 
For detailed dengue clinical management more information, access the CDC Dengue Pocket guide and visit CDC’s dengue information for healthcare professionals.
 
Public Information from the CDC and Medscape