The first symptoms of dengue appear two to seven days after the bite of the tiger mosquito. Others can then occur, more or less severe, as our specialist from the Pasteur Institute explains to us.
Dengue fever ortropical flu” is a disease transmitted by an infected mosquito, arbovirus vector. According to Anna-Bella Failloux, professor of medical entomology and head of the arbovirus and insect vector research unit the Pasteur Institute, “cases are arriving in mainland France. These cases may be the origin of indigenous cases in regions of France where high densities of tiger mosquito, transmitter of the dengue virus. These imports can come from South-East Asia or even overseas territories (Guyana, Polynesia, Guadeloupe, Reunion, Martinique). Each year in the world, we have between 100 million symptomatic cases compared to 300 million asymptomatic cases, specifies the expert. Dengue causes between 20,000 and 30,000 deaths every year. In 2022, France experienced a peak in dengue fever, with more than 65 symptomatic cases in the Southern region. However, we can multiply this figure by three, if we take into account patients who had no symptoms. Not everyone develops dengue fever symptoms. Indeed, 3/4 of patients are asymptomatic, i.e. approximately 75% of cases.
The first signs at the onset of classic dengue
The incubation period for classic dengue is 2 to 7 days, the period during which the person is infectedbut does not develop symptoms.
► A high fever appears suddenly, associated with headache.
► Other symptoms appear, such as muscle and/or joint pain.
► buttons : “Most arboviruses cause these symptoms, but dengue causes rash”, explains Anna-Bella Failloux.
► After a few days, symptoms may intensify. “For example, the patient may have a nosebleed or bruising.”
A rash that looks like measles
The rash in classic dengue is comparable to that of measles. It is small red and slightly raised spots, which appear on the skin. The first red spots appear on the chest in case of dengue fever and rather on the face in case of measles. In the case of cutaneous dengue hemorrhagic fever, red patches visible through the skin are appearing.
Digestive symptoms: stomach ache, nausea
Classic dengue fever can lead to the occurrence of digestive symptoms, such as nausea, abdominal pain, vomiting, or diarrheaalthough it is not not the characteristic sign of dengue. Gastrointestinal bleeding is one of the symptoms of the severe form of the disease. “Hospitalization may be necessary. Sometimes, blood transfusion is obligatory to avoid a lethal outcome“, says our entomology specialist.
How long does dengue last?
In a classic case of dengue fever, the symptoms regress within a few days. “After a week on average, the symptoms disappeared. Classic dengue is not a severe disease, but a debilitating viral infection.
The most serious symptoms of dengue hemorrhagic fever
In some patients, the clinical picture evolves towards more severe symptomsit’s about the dengue hemorrhagic fever. “These patients represent approximately 1% of symptomatic cases of dengue in the world. When symptoms persist, skin and/or brain hemorrhage can appear and lead to death”, explains our expert. THE children under 15 and the elderly are at risk, because their immune system is more immature or weakened than the rest of the population. Louser avoid dengue fevermeans of prevention exist, such as vaccine developed by Sanofi-Pasteur. “This vaccine, which targets the 4 serotypes, is used only in people between the ages of 9 and 45, with a history of dengue fever. Other methods are associated, such as vector control and health education, such as the imperative elimination of larval breeding sites.“, concludes Anna-Bella Failloux.