A Rising Threat in 2024
The Centers for Disease Control and Prevention (CDC) has issued a Health Alert Network (HAN) Health Advisory to inform healthcare providers, public health authorities, and the public about an increased risk of dengue virus (DENV) infections in the United States in 2024. The global incidence of dengue this year has reached unprecedented levels, with countries in the Americas experiencing record-breaking numbers of cases. This article aims to provide comprehensive information on the current dengue situation, recommended healthcare measures, and preventative strategies to mitigate the risk of dengue infections.
Global Surge in Dengue Cases
Record-Breaking Numbers in the Americas
In 2024, the Americas have reported over 9.7 million dengue cases from January 1 to June 24, a significant increase from the 4.6 million cases recorded in all of 2023. This surge has prompted public health emergencies in various regions, including Puerto Rico, which has declared an emergency due to 1,498 cases. Additionally, there have been 745 cases identified among U.S. travelers during the same period.
Understanding Dengue Virus
The Arboviral Disease
Dengue is the most common arboviral disease globally, caused by four distinct but closely related dengue viruses (DENV-1, -2, -3, and -4). These viruses are transmitted through the bites of infected Aedes species mosquitoes. While infection with one DENV typically provides lifelong immunity against that specific virus, it only offers temporary protection against other strains.
Symptoms and Severity
Approximately one in four DENV infections are symptomatic, ranging from mild to severe. Symptoms usually appear after an incubation period of 5-7 days and include fever, nausea, vomiting, rash, muscle aches, joint pain, bone pain, pain behind the eyes, headache, and low white blood cell counts. Severe dengue can lead to severe bleeding, shock, or respiratory distress and is more likely with a second DENV infection.
Dengue in the United States
Endemic Areas and Local Transmission
Dengue is a nationally notifiable disease in the United States. Six U.S. territories and freely associated states—Puerto Rico, American Samoa, the U.S. Virgin Islands, the Federated States of Micronesia, the Republic of Marshall Islands, and the Republic of Palau—are classified as areas with frequent or continuous dengue transmission. Local transmission has been limited but reported in Florida, Hawaii, Texas, Arizona, and California.
Recommendations for Healthcare Providers
Increased Vigilance and Testing
Healthcare providers should maintain a high suspicion of dengue in patients with fever who have traveled to areas with frequent or continuous dengue transmission within 14 days before illness onset. Appropriate diagnostic tests for acute DENV infection, such as reverse transcription polymerase chain reaction (RT-PCR) and IgM antibody tests, or non-structural protein 1 (NS1) antigen tests and IgM antibody tests, should be ordered.
Management and Reporting
Timely reporting of dengue cases to public health authorities is crucial. Providers should also educate patients about mosquito bite prevention measures and be prepared to manage dengue cases effectively, especially in high-risk populations.
Public Health Recommendations
State, Tribal, Local, and Territorial Health Departments
Health departments should ensure access to FDA-approved dengue testing and remind clinicians of the high risk of dengue among patients with fever and recent travel history. Public health authorities should also inform healthcare providers and the public about local transmission and travel-associated cases, and report cases to the CDC via ArboNET.
Preventative Measures for the Public
The public should be educated on mosquito bite prevention, including the use of EPA-approved repellents, wearing loose-fitting, long-sleeved clothing, and controlling mosquitoes at home by using air conditioning and window screens, and eliminating standing water.
Conclusion: Addressing the Dengue Threat
The increased risk of dengue virus infections in the United States in 2024 requires coordinated efforts from healthcare providers, public health authorities, and the public. By maintaining vigilance, employing appropriate diagnostic tests, reporting cases promptly, and promoting mosquito bite prevention, we can mitigate the impact of this growing public health threat.