More than 1,600 imported cases of dengue fever have been detected on mainland France since January – Libération

It measures just five millimeters, but its black and white striped body is increasingly worrying health authorities. Tiger mosquito and the viruses it transmits. “arboviruses” – are spreading exponentially. This refers to Dengue fever. Since January 1, 1,679 cases have been imported from this region. “tropical flu” were discovered on mainland France. This is eleven times more than in the same period last year, when there were 131. “We are faced with an unprecedented situation”– confirms Caroline Semaj, President of Public Health of France, at a press conference on Tuesday, April 23.

20% of these cases involve people over 65 years of age, and “many families”, But “few children”. All were imported. In other words, the infected people were bitten outside mainland France. Mainly overseas: Guadeloupe, Martinique and, to a lesser extent, Guyana. “What we are seeing in France is a mirror of what is happening in the Antilles and South America.”, the epidemiologist emphasizes. And for good reason: Latin America and the Caribbean is currently facing an outbreak. “never achieved.” Since January 1, more than 4 million cases have been recorded. The level is three times higher than in 2023 and more than 5 times the average over the past five years.

Flu symptoms

“Dengue affects infants, children and adults alike. Most infected people show no or very mild symptoms.“, describes health director general Gregory Emery for his part. These illnesses more or less resemble the flu syndrome: fever, headache, muscle pain, fatigue, nausea and vomiting. They appear on average 4–7 days after an insect bite. Worldwide, 1% of cases develop into a severe form: fever persists and is accompanied by potentially fatal hemorrhage with possible neurological damage.

No serious illness or death has yet been reported on mainland France. But dengue is one of 35 infectious diseases listed in early April by Covars (a scientific committee) that are considered major risks to human health in the coming years. Because as the incidence increases, the number of serious cases also increases. Moreover, there is no specific treatment at the moment – medications only affect the symptoms. Aspirin and nonsteroidal anti-inflammatory drugs (eg, ibuprofen) are contraindicated due to the risk of bleeding.

At this stage of the year, the task of health authorities is to limit as much as possible “transmission chains”. That is, to prevent infected people from being bitten by tiger mosquitoes that carry the disease, which then infect others. And therefore create clusters of “native” cases – last year, 45 were identified in nine clusters. As the tiger mosquito spreads more and more in France due to more favorable temperatures associated with climate change, the risk of transmission increases. It has colonized 78 departments, up from 59 in 2019.

In 2024, no major cases were recorded – the period of mosquito activity, and therefore supervision by the authorities, begins on May 1. But they probably will. “The risk of dengue fever is part summer risks», confirms Gregory Emery. The disease has even infiltrated the number of health risks identified during the Olympic Games. Which will begin in the middle of the summer period, which is favorable for tiger mosquitoes. And the arrival of thousands of visitors also increases the risk of importing dengue fever.

Empty cups and gutters

Hence the calls for vigilance and reminders of preventive measures. “The tiger mosquito needs shelter and shelter, – sums up the epidemiologist. Stagnation is stagnation of water. The cover is blood.” Since these insects bite only a few hundred meters from their birthplace, “The first step is to eliminate stagnant water.”, insists Gregory Emery. Because a few millimeters of water in a flower cup or gutter is enough to serve as a nest for them.

“The second measure concerns people who travel to risk areas.– continues the public health doctor. On site, they must protect themselves as much as possible from bites.. Namely, wear long, loose clothing, use repellent and mosquito nets. Then maintain these protective measures three weeks after returning from your trip. And see your doctor if you experience symptoms. These precautions also protect against two other viruses also transmitted by tiger mosquitoes: chikungunya and Zika (30 and 9 cases respectively on mainland France in 2023).

From a therapeutic point of view, two dengue vaccines are currently approved. But the first one is shown only to people who have already been ill. As for the second, health authorities are waiting for recommendations from the Supreme Health Authority to include it in the vaccination calendar. Its conclusion is expected in June.