Zika, dengue, chikungunya: systematic surveillance of the tiger mosquito has become necessary in France

The tiger mosquito continues its colonization of the French departments: 42 are placed in red vigilance and 18 in yellow vigilance.

"Its ability to be 'vector' of chikungunya, dengue or zika, makes it a priority surveillance target, for the health authorities and their partners during its period of activity in metropolitan France from May 1 to November 30." The Ministry of Health has announced the strengthening of surveillance of the tiger mosquito in France, both to slow its growth and "limit the risk of importation and circulation of viruses which it can be the vector in mainland France."

According to the specialized site Vigilance mosquitoes, "the progression of the mosquito tiger this year was spectacular with nine new departments colonized and placed in vigilance-red": Hauts de Seine, Aisne, Hautes Alpes, Hautes Pyrenees, the Ariège, Lozère, Indre, Maine-et-Loire and Corrèze. Although less sunny, the Ile-de-France is also concerned: the Val de Marne and the Hauts de Seine are in red alert and in addition to Paris, 4 departments are vigilant orange: the Val d'Oise, the Seine and Marne, Essonne, Seine-Saint-Denis, where the tiger mosquito has been intercepted during the last 5 years.

In total, 96 departments are concerned: 42 are in red alert, 18 in orange alert and 34 in yellow vigilance. Vigilance-Mosquito observes that in the vast majority of cases, departments in orange go into red vigilance in the following years. "They therefore require particular citizen vigilance, especially since they do not benefit from the entire device provided by the anti-dissemination plan" planned in departments placed in red vigilance.

Why are you so suspicious of the tiger mosquito?

The tiger mosquito is a vector of several diseases such as Zika, dengue and chikungunya. It is infected by biting a sick traveler, carries the virus and secondarily transmits it to non-immune people during a next bite. Thus, a cycle of autochthonous transmission is generated and can be at the origin of one or more outbreaks. In France, 11 indigenous dengue cases were reported in Hérault in 2014, 7 indigenous dengue cases in the Gard in 2015 and 17 indigenous cases of chikungunya in the Var in 2017. In 2007, a person carrying chikungunya landed in Italy in June. In early July, the first indigenous case was reported and another 300 cases were reported in the north after a month and a half.

What is chikungunya?

Chikungunya is a viral disease also transmitted by the bite of a tiger mosquito. The name "chikungunya" comes from a verb of the kimakonde language which means "to become twisted" in reference to the hunched appearance of those who suffer from joint pains. Indeed, chikungunya is characterized by the sudden onset of fever often accompanied by joint pain (often disabling, but it usually disappears after a few days or weeks).

Cases of myalgia, headache, nausea, fatigue and rash have also been observed. Most patients recover well, but in some cases, joint pain persists for months to years. But let's be honest, this remains theoretical in metropolitan France and the risks are extremely weak for the moment.

Dengue, or "tropical flu"

Dengue, also called "tropical flu", is a tropical haemorrhagic fever linked to an arbovirus, transmitted by the bite of a female tiger mosquito only. The World Health Organization (WHO) estimates that there are 50 million annual cases worldwide, including 500,000 cases of dengue "haemorrhagic", ie which are fatal in more than 2.5% of cases . Dengue fever is initially present in the tropical and subtropical areas of the world.

Symptoms occur after 3 to 14 days (average 4 to 7 days) after the infective bite. Influenza-like illness occurs in infants, young children and adults. There is no specific treatment. While dengue haemorrhagic fever is a life-threatening complication, early clinical diagnosis and rapid clinical management often save lives.

As the Organization for Health (WHO) points out, "more than 70% of the disease burden in Southeast Asia and the Western Pacific is found in Latin America and the Caribbean. Both the incidence and severity of the disease have increased rapidly in recent years, and Africa and the Eastern Mediterranean have also experienced more outbreaks in the last decade. " Recently, nearly 1,300 cases of dengue fever have been confirmed in the north, west and south of Reunion since 1 January 2018.

Video: Dengue and Chikungunya in Our Backyard: Preventing Aedes Mosquito-Borne Diseases (January 2020).