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Arboviral diseases: a threat on Earth

Arboviruses are arthropod-borne diseases, i.e. viruses transported by arthropods able to transmit a disease to other animals or humans. They belong to different families of viruses such as Flaviviridae or Togaviridae. The main viruses found in those families are, respectively, Dengue, Zika virus (genus Flavivirus), and Chikungunya virus (genus Alphavirus). They are responsible for diseases called arboviral diseases. They mainly impact populations living in tropical areas. However, due to population movements and climatic changes, arboviral diseases are now spreading all around the world (1).

Repartition of different arboviruses in the world. JEV: Japanese Encephalitis Virus; DENV: Dengue Virus; YFV: Yellow Fever Virus; ZIKV: Zika Virus; CHIKV: Chikungunya Virus; RVFV: Rift Valley Fever Virus; MAYV: Mayaro Virus; OROV: Oropouche Orthobunyavirus. (2)

Tiger mosquito: the main vector of arboviral diseases

Aedes albopictus commonly known as tiger mosquito is found in the tropical forests of Asia. Its ability to adapt, as a result of evolution, allows him to colonize urban environments today. A container of stagnant water is sufficient for them to lay their eggs and proliferate quickly. Indeed, the female tiger mosquito can lay 150 eggs every 12 days. It has been reported that, by the end of 2020, tiger mosquitoes have established in 64 departments in France (3).

Both males and females feed mainly on the sweet nectar contained in flowers but are also opportunistic anthropophilic insects, as they can feed directly on the blood of humans (only females). The bite of a mosquito is very unpleasant and disturbs its victim, yet this is nothing compared to the diseases that can be transmitted by the mosquito saliva.

As described above, arboviruses need arthropods to replicate, one of them is the tiger mosquito. Indeed, these insects are the main vector of Dengue, Chikungunya, Yellow fever and Zika viruses. Consequently, from a sick person, the circulation of a virus can be greatly accelerated by tiger mosquitoes, turning an isolated case into an uncontrollable epidemic. The exponential increase in the population of the tiger mosquito in France enhances the appearance of arboviral diseases. Indeed, since 2018, five local cases of Dengue fever have been detected in the PACA region, in patients who had only been in contact with tiger mosquitoes in metropolitan France.

Because of the threat of the emergence of arboviral diseases, such as Zika, with high epidemic potential, there is an emergency to develop early detection systems to prevent and avoid epidemics in the world but also in the Mediterranean area of Europe and France (1).

Repartition of the tiger mosquito in the world.

Aedes albopictus repartition in French department known on the 1st of January 2021. (3)

Current solutions

The only solution that exists today to prevent the spread of tiger mosquitoes, thus of arboviral epidemics, is to spray pesticides heavily to wipe out the mosquito population in a treated area. This kind of treatment is linked to several problems. First, mass spraying of pesticides does not only kill mosquitoes, but also other insects. Secondly, the treatment is not sustainable over time; when the product is used up in the environment, the mosquitoes start to proliferate in the area again. Finally, mosquitoes are pollinators and also part of the food chain, so it is important not to kill them all.

Our solution: the balance between biodiversity and health risk

ARBO-BLOCK aims at deleting only the mosquitoes that carry a dangerous virus. After discussion, extensive research, and interviews with specialists, we have realized that killing all mosquitoes was not the answer. But targeting mosquitoes that carry a virus could be a future solution to prevent the epidemic spread of viruses.

We have decided to use an engineered bacterium from the Asaia genus. This way, we would modify a strain present in the mosquito’s midgut by helping it detect a specific virus. It would be given to mosquitoes as a sugary bait so that it will be easily eaten. Using this specific bacterium, our technology would be easily spread into the ecological niches of the mosquito to infect it and would be able to be transmitted to subsequent generations. When the bacterium enters the midgut of the insect and detects an arbovirus, the recognition would trigger an engineered pathway in the cell to produce a toxin in sufficient quantity to kill the infected mosquito.


  1. World Health Organization. (2020). Establishing syndromic surveillance and event-based surveillance systems for Zika, dengue and other arboviral diseases.
  2. Weaver, S. C., Charlier, C., Vasilakis, N., & Lecuit, M. (2018). Zika, Chikungunya, and Other Emerging Vector-Borne Viral Diseases. Annual Review of Medicine, 69, 395–408.
  3. ANSES (Agence nationale de sécurité sanitaire de l’alimentation, de l’environnement et du travail). Ministère Français des Solidarités et de la Santé.
  4. Dickens, B. L., Sun, H., Jit, M., Cook, A. R., & Carrasco, L. R. (2018). Determining environmental and anthropogenic factors which explain the global distribution of Aedes aegypti and Ae. Albopictus. BMJ Global Health, 3(4), e000801.
Team Aix-Marseille

Team iGEM Aix-Marseille 2021

We are pleased to present to you the 8th generation of Aix Marseille University team! The team is eclectic and comes from various backgrounds: students from the Faculty of Science in their 3rd year of Bachelor’s Degree, 1st year and 2nd of Master’s specialized in Microbiology, but also Engineering students in Biotechnology in their 4th or 5th year of study (equivalent of a Master’s Degree). This diversity has allowed us to gather and share our diverse knowledge and multiple experiences to move forward together in this competition.

If you want to learn more about each member of the AMU TEAM, their post/position, background and passions, follow the link!

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The whole team Aix-Marseille 2021