The tiger mosquito is now present in 70 departments of France and in July 2022, it favored the eruption of around sixty indigenous cases of dengue fever in the south of France. Never seen ! At the Pasteur Institute, a Tahitian researcher is studying this mosquito very closely. Anna-Bella Failloux is in #MaParole.
Her parents ran a grocery store in Papeete and encouraged their five daughters to study. During the holidays, they had to lend a hand to run the business. And at school, you had to work. Anna-Bella Failloux, the eldest of the siblings, chose biology. Today, she is a recognized scientist, director of the Arboviruses and insect vectors unit at the Institut Pasteur in Paris. In other words, a mosquito specialist. Anna-Bella Failloux has just signed a book with other researchers entitled The mosquito, public enemy number 1? published by Quae.
1 The big leap
What is a vocation as a researcher? For Anna-Bella Failloux, it’s simple. At La Mennais high school in Tahiti, a biology teacher gave him a taste for this demanding discipline. They called her Sister George, a good sister who added from Guyana. Added to this, the will to succeed. At home, work was the norm. “My parents are 3rd generation Chinese who speak Cantonese with lots of Tahitian expressions and who never stopped working”says the researcher
Studious, the teenager worked hard to obtain a scholarship and go to study plant physiology in Toulouse. She had never flown and did not know France at all. A big leap. “This first year at Paul Sabatier University in Toulouse was very important, because if things went well, my sisters could then join me to study. If it went wrong, my parents would have been very annoyed“. The student must succeed… No choice.
After a DEA in plant physiology (the equivalent of a Master 2), Anna-Bella Failloux joined the Louis Malardé Institute. She then took a close interest in lymphatic filariasis. It is a disease caused by a worm transmitted by the Aedes polynesiensis mosquito. Worms reproduce and grow in the human body, limiting the flow of lymph. People can then find themselves with huge legs infected with worms, hence the other name for this disease: elephantiasis. For six years, Anna-Bella Failloux worked on the transmission of this disease at the Louis Malardé Institute and completed her studies with a thesis on this subject at the University of Orsay.
In 1988, Anna-Bella Failloux studied for three months under entomologist François Derhain at the Institut Pasteur in Paris. Passionate about the study of insects, she decided to contact the professor again to continue her research with him in post-doctorate. In 1993, Anna-Bella Failloux left Polynesia for the Institut Pasteur in Paris, which she joined by competitive examination three years later. She then became interested in mosquito vectors of dengue fever, chikungunya, zika or yellow fever. This is called vector transmission. “The female mosquito, and not the male, bites for its blood meal about 3 to 4 microliterssays Anna-Bella Failloux. This blood is necessary for the female to ensure the development of her eggs. At the same time, it takes pathogens in humans, this is where the mosquito becomes a vector of dengue for example“.
3 mosquito specialist
In her laboratory, Anna-Bella Failloux studies mosquito vectors of disease in all directions. Thanks to his work, we know a little more about these mosquitoes that transmit diseases. “The female mosquito can live between two and three monthssays Anna-Bella Failloux. It can swallow during a blood meal 1 billion viral particles. Knowing that it bites 1 to 2 times a week, we understand that epidemics can spread very quickly..”
With climate change, there is a risk of more epidemics, according to the researcher. “When the temperature is higher and there is humidity, the incubation time of viruses is faster in the mosquitonote Anna Bella Failloux. For dengue fever, if the temperature rises to around 24°, the tiger mosquito takes an average of 7 to 10 days before being able to transmit the disease after its blood meal. If the thermometer displays 30°, this period is reduced to 5 days“. The study of mosquitoes therefore has a bright future ahead of it.
According to the WHO, we are witnessing an increase in dengue fever cases. There were 2 million 4 in 2010, in 2019 we were at 5 million 2. “All mosquitoes will be resistant to all insecticides and research must anticipate this problem“, adds Anna-Bella Failloux. So to fight against the mosquito vectors of dengue fever, you have to show imagination. There is no shortage of researchers. Much research has focused in recent years on the modification of Aedes aegypti mosquitoes. to make them harmless to humans.
Some teams have had the idea of introducing a bacterium called Wolbachia into Aedes aegypti type mosquitoes. From 2019, in New Caledonia and then in Polynesia, releases of mosquitoes carrying this bacterium took place with the aim of harming their offspring. In July 2022, there were releases of sterile males in Reunion. In #MaParole, Anna-Bella Failloux explains that the first method appears very effective in Noumea.
Since 2019, the Institut Pasteur has had a 140 square meter insectarium for breeding and studying mosquitoes. It is a P3 type laboratory which requires wearing a full suit under a temperature of 24° which you have to get used to. Anna-Bella Failloux, who leads the Arboviruses and insect vectors team, watches over this insectarium, but sometimes goes to Polynesia or elsewhere to collect mosquitoes from landfills or crab holes. Places not very “glamorous”! “Nothing replaces the field for a researcherr” estimates the mosquito specialist, even if since the Covid, travel has been greatly reduced.
►28 avril 1963
Born in Papeete
Arrival in Toulouse
Admission to the Malardé Institute in Tahiti
Joining the Institut Pasteur
Ability to conduct researches