Key points about Dengue

Dengue is an acute viral disease transmitted to humans through the bite of mosquitoes of the Aedes genus.
It is widespread in tropical and subtropical regions and is now one of the major arboviruses in the world.
The majority of infections are asymptomatic or mild, but some forms can progress to severe, potentially fatal dengue.
There is no specific antiviral treatment for dengue, and management is essentially based on symptomatic treatment.
Prevention relies primarily on mosquito control and individual protection, with vaccination playing only a limited and targeted role.

What is dengue fever?

Dengue is a viral infectious disease of tropical areas and subtropical regions worldwide, caused by a flavivirus, of which there are four distinct serotypes (DENV-1 to DENV-4). The infection is transmitted to humans through the bite of infected mosquitoes, primarily Aedes aegypti and Aedes albopictus, which are most active during the day, particularly in urban areas where they breed in stagnant water. After an incubation period of 3 to 14 days, the virus multiplies in the body and can cause acute illness.

Infection with one serotype confers lasting immunity against that serotype, but only transient protection against others, which explains the increased risk of severe illness with successive infections. Other, less common, modes of transmission are possible. A pregnant woman with dengue can transmit the virus to her baby, increasing the risk of prematurity, low birth weight, or fetal distress. Dengue can also be transmitted, in exceptional cases, through blood products, organ donations, and transfusions.

Dengue fever worldwide

La dengue represents a a major global public health issuedengue fever has seen a dramatic increase in incidence over the past few decades. In 2024, more than 14,3 million cases were reported to the World Health Organization (WHO) in over 100 countries, a record high. During the same period, more than 11,000 deaths from dengue fever were reported to the WHO worldwide. The disease affects all regions of the world, but the majority of cases are concentrated in tropical and subtropical areas, particularly in Southeast Asia, the Americas, and Africa.

International estimates suggest that approximately 390 million infections occur worldwide each year, of which nearly 96 million are clinically apparent. This high burden is underestimated in official data due to the underreporting of mild or asymptomatic cases. For 2025 alone, over 4 million cases and more than 3,000 deaths have already been reported to the WHO to date, in at least 97 countries and territories, demonstrating that transmission remains highly active. Rapid urbanization, globalization of trade, international travel, and the geographic expansion of Aedes mosquitoes, facilitated by climate change, contribute to the continued spread of dengue. In non-tropical areas, particularly in Europe, autochthonous cases can occur sporadically in regions where Aedes albopictus (tiger mosquito) is established, especially during the summer months.

Dengue symptoms

La dengue is often asymptomatic ou paucisymptomaticWhen symptomatic, it usually begins abruptly with a high fever, associated with severe headachesretro-orbital pain, myalgia and marked joint pain and significant fatigue. digestive symptoms (Nausea, vomiting), as well as a skin rash, are common. minor bleeding signsSymptoms such as bleeding gums or nosebleeds may be observed. In a small percentage of cases, the disease progresses to severe or hemorrhagic dengue, a potentially fatal condition characterized by plasma leakage, severe bleeding, and multi-organ involvement. This critical phase usually occurs during the defervescence period and requires urgent medical attention. Patients most at risk of developing a severe form and requiring close monitoring include young children, the elderly, pregnant women, patients with chronic illnesses, those taking anticoagulants, and those with a history of dengue.

Dengue diagnosis

Le dengue diagnosis Diagnosis is based on a combination of clinical, epidemiological, and biological data. It should be considered in the presence of an acute febrile syndrome in a person who has stayed in an area where the virus is circulating or who resides in an area where the vector is present. Biological confirmation relies on direct detection of the virus (PCR, NS1 antigen) in the early stages, or on the detection of specific antibodies at a later stage. Laboratory tests frequently show thrombocytopenia, leukopenia, and sometimes elevated transaminases, which are useful for monitoring severity.

Dengue treatment

There is no specific antiviral treatment for dengue. Management is based on symptomatic treatment, including rest, hydration, and the use of antipyretics. Nonsteroidal anti-inflammatory drugs (NSAIDs) and aspirin are contraindicated due to the risk of bleeding. Moderate to severe cases require close medical monitoring, particularly during the critical phase, to detect early signs of severe dengue and prevent complications.

Dengue prevention

Dengue prevention relies primarily on controlling mosquito vectors and reducing breeding sites, particularly in urban areas. Individual protection includes the use of skin repellents, protective clothing, and mosquito nets, even during the day. Dengue vaccination is available, but its use is limited to specific populations based on age, serological status, and national recommendations. It does not replace vector control measures. At the community level, epidemiological surveillance, early case detection, and coordinated vector control efforts are essential to limit transmission and prevent outbreaks.

The dengue