Anna-Bella FAILLOUX
Arboviruses and Insect Vectors Unit
Institut Pasteur 25-28 rue du docteur Roux, 75015 Paris
 
 
Research area of the Unit
The objectives of our group are to dissect the changes in mosquito population structure leading to the selection of new viral variants causing new epidemic outbreaks. For doing so, different combinations of viruses/blood-feeding mosquitoes have been addressed.
- The Rift Valley fever virus (RVFV) and the consequences of host alternation on evolution of viral populations: we demonstrated that freeing RVFV from replicating in alternation between insects and vertebrates results in deletions of the non-structural gene encoding for the virulence factor. Virulence is likely to be restored when alternation between animals and vectors is initiated again through the acquisition of a complete NSs gene consecutive to gene reassortments in vectors.
- The chikungunya virus (CHIKV) and the consequences of vector changes on the selection of new viral variants: we found that recent CHIKV emergence wasassociated with small viral changes causing better transmission by an unusual CHIKV vector, Aedes albopictus.
- Role of bacteria in modulating vector competence: we showed that theendosymbioticbacterium Wolbachia is able to interfere with arbovirus replication and transmission.
 
Contribution to the programme
The introduction and establishment of the mosquito Aedes albopictus in Europe remain a public health concern, as Ae. albopictus transmits a large number of arboviruses including chikungunya (CHIK) and dengue (DEN) viruses. These temperate populations can lay diapausing eggs, more resistant to desiccation and low temperatures. In addition, they are competent vectors in the field since an epidemic of CHIK occurred in Italy in 2007 and autochthonous cases of CHIK and DEN were reported in south-eastern France in summer 2010. Arbovirus transmission by mosquitoes is known to be influenced by climatic factors including temperature, which can impact on vector competence of mosquitoes. Temperature can modulate virus replication within the mosquito vector by affecting the time required for the virus to replicate in the vector prior to transmission. We will be involved in the Labex IBEID by defining the vectorial status of mosquitoes in newly emerged arboviral diseases and determining the impact of climatic changes on arbovirus transmission, principally in Europe.
 
References over the past 5 years
  1. Blagrove M.S.C., Arias-Goeta C., Failloux A.-B. and Sinkins SP. 2011. The Wolbachia strain wMel induces cytoplasmic incompatibility and blocks dengue transmission in Aedes albopictus. Proc Natl Acad Sci USA 109(1): 255-260.
  2. Moutailler S., Roche B., Thiberge J.-M., Caro V., Rougeon F. and Failloux A.-B. 2011. Host alternation is necessary to maintain the genome stability of Rift Valley fever virus. PLoS Neglected Tropical Diseases 5(5): e1156.
  3. Vazeille M., Mousson L., Martin E. and Failloux A.-B. 2010. Orally Co-infected Aedes albopictus from La Reunion Island, Indian Ocean, Can Deliver both Dengue and Chikungunya Infectious Viral Particles in their Saliva. PLoS Neglected Tropical Diseases 4(6): e706.
  4. Martin E., Moutailler S., Madec Y. and Failloux A.-B. 2010. Differential responses of the mosquito Aedes albopictus from the Indian Ocean region to two chikungunya isolates. BMC Ecology 10: 8.
  5. Mousson L., Martin E., Zouache K., Madec Y., Mavingui P. and Failloux A.-B. 2010. Wolbachia modulates Chikungunya replication in Aedes albopictus. Molecular Ecology 19(9): 1953-1964.
  6. Dubrulle M., Mousson L., Moutailler S., Vazeille M. and A.-B. Failloux. 2009. Chikungunya virus and Aedes mosquitoes: saliva is infectious as soon as two days after oral infection. PLoS ONE 4(6): e5895.
  7. Vazeille M, Moutailler S, Coudrier D, Rousseaux C, Khun H, Huerre M, Thiria J, Dehecq JS, Fontenille D, Schuffenecker I, Despres P, and Failloux AB. 2007. Two Chikungunya Isolates from the Outbreak of La Reunion (Indian Ocean) Exhibit Different Patterns of Infection in the Mosquito, Aedes albopictus. PLoS ONE 2(11): e1168.