Santé Publique France is warning this Tuesday on the risk of transmission in metropolitan France of exotic diseases such as chikungunya, dengue fever or the zika virus through the tiger mosquito.
Physicians should keep in mind that the chikungunya, dengue or zika can be diagnosed even in people who have not traveled because the tiger mosquito, which transmits these exotic diseases, is spreading in metropolitan France, warns the health agency Public Health France (SpF) on Tuesday.
“The awareness of doctors to the diagnosis of arbovirus (this family of viral diseases, editor’s note) in a person who has not traveled is to be strengthened”, estimates the agency in its weekly epidemiological bulletin devoted to the surveillance of these diseases in 2019 .
“In total, in 2019, 113 confirmed or probable cases of chikungunya, 923 cases of dengue fever and 17 cases of zika virus infection” were identified in metropolitan France.
“Native” cases of disease
At the same time, the tiger mosquito (Aedes albopictus) “continues to establish itself in new departments each year in mainland France” with “51 departments colonized in 2019” against 42 in 2018.
Almost all of the approximately 1,050 cases involved people who had traveled to high-risk countries and had been infected there before returning to France. But a handful, or 12, were “indigenous cases”, that is to say infections contracted via a mosquito bite in metropolitan France: nine cases of dengue and three of zika.
The three indigenous cases of zika were detected in August 2019 in Hyères (Var). Before that, no case of indigenous transmission of this disease had been spotted in Europe, “despite hundreds of cases imported during the 2016 epidemic” which had started in Brazil.
These three cases “resided within a radius of 50 meters and all had adjoining gardens. They reported being ‘very bitten’ and that mosquitoes were ‘very numerous’ in their homes,” according to Public Health France. The chain of transmission then “probably regressed on its own”. It is not known how it started: one of the hypotheses, which is not confirmed, is that the virus had been introduced in Hyères by a person returning from Thailand.
In addition, seven indigenous cases of dengue were spotted in the Maritime Alps between July and August 2019. But two others were also identified further north, in the Rhône, at a less hot period, in September.
“This is the first detection of outbreaks of indigenous cases of arboviruses in Auvergne-Rhône-Alpes while the presence (of the tiger mosquito) is intensifying a little more each year in the region”, underlines Public Health France.
This episode started with a person “returning from Cambodia at the end of June”, who lived within 100 meters of one of the two indigenous cases. “It is essential to educate travelers so that they can protect themselves against mosquito bites in traffic areas and so that when they return from these areas, they (…) consult a doctor as quickly as possible if they present suggestive signs “of the disease, recommends Public Health France.