The adaptive nature of plague transmission by fleas – ADAPT

Flea-borne plague, caused by the bacterium Yersinia pestis, is a deadly re-emerging disease that primarily affects rodents and occasionally humans. The disease occurs cyclically each year in some parts of the world, but it can also re-emerge after decades of silence or even disappear after decimating populations, as has been the case in Europe. We have a partial understanding of the mechanisms of plague seasonality and a severe lack of knowledge about its mechanisms of re-emergence and extinction. Recently published studies and preliminary data from our consortium suggest that plague dynamics and extinction are related to the microevolution of the Y. pestis genome as well as to the extrinsic and intrinsic properties of the flea vector. Therefore, our project aims at ( 1) demonstrating that these two novel parameters are key players in plague dynamics and/or extinction and (2) determining where, when, why and how these evolutionary events occur (i.e. decipher the biological and molecular mechanisms). To this end, we will combine medical entomology, bacteriology, molecular biology and several omics methodologies. Finally, the experimental biological data from our two objectives above will be incorporated into mathematical/epidemiological models that we will develop to better decipher the dynamics and extinction mechanism of the flea-borne plague. Overall, we expect that our interdisciplinary approach (experimental biology and health and ecological/environmental sciences), which has never been implemented in plague research before, will ultimately provide an ecological approach targeting the main plague reservoir (fleas) to control the disease.