Combe marine

I am working on the interactions between emerging pathogens (i.e. bacteria, virus, fungi) and their host/environment. I study the genetic diversity of generalist pathogens infecting animals and/or humans by focusing on the identification, prevalence and distribution of the various environmental strains of those pathogens, including infectious (cause a disease in animals/humans) and non-infectious (only found in the environment) strains. The aim of my work is to better understand the mechanisms underlying the emergence of aquatic – freshwater and aquaculture systems – pathogens in developing countries.

In French Guiana I focus on the genetic characterisation of environmental strains of Mycobacterium ulcerans, and their spatio-temporal dynamics in freshwater ecosystems. In parallel, I develop eDNA approaches allowing the quick characterization of the various mycobacterial species found in freshwater systems.

In addition, I work on the genetic characterization of strains of Sphaerothecum destruens, a newly emerged fish parasite known as « rosette agent ». This parasite has been dispersed from China through Asia and Europe during the invasion process of its healthy carrier host Pseudorasbora parva, a highly invasive fish species, notably in aquaculture systems. My work aims to identify the various strains of this pathogen in different freshwater catchments and aquaculture reservoirs, as well as to study the co-evolution process between P. parva lineages and S. destruens strains.


  • ANR PRIME (ANR-17-CE35-0006-01, 2018-2021) - IRD, Guyane française
  • MicroBIOMES project (2016-2020) - Institut Pasteur-IRD, Guyane française Funding: LabEx CEBA Guyane, CNRS
  • ROSETTA project (2017-2019) - IRD, France Funding: Agence Française pour la Biodiversité (AFB) –
    1. Marine Combe, Rodolphe Elie Gozlan (2018). The rise of the Rosette Agent in Europe: an Epidemiological Enigma. In revision in Transboundary and Emerging Diseases.
    2. Bettarel Yvan, Combe Marine, Adingra Antoinette, Ndiaye Awa, Bouvier Thierry, Panfili Jacques, Durand Jean-Dominique (2018). A horde of phages in the fish gut: the case of the tilapia Sarotherodon. In revision in Scientific Reports – Nature.
    3. Marine Combe, Camilla Jensen Velvin, Aaron Morris, Andres Garchitorena, Kevin Carolan, Daniel Sanhueza, Benjamin Roche, Pierre Couppié, Jean-François Guégan, Rodolphe Elie Gozlan (2017). Global and local environmental changes as drivers of Buruli ulcer emergence. Emerging Microbes and Infections – Nature, 6: e20. doi: 10.1038/emi.2017.7.
    4. Marine Combe, Raquel Garijo, Ron Geller, José M. Cuevas, Rafael Sanjuán (2015). Single-cell analysis of RNA virus infection identifies multiple genetically diverse viral genomes within single infectious units. Cell Host & Microbe, 18: 424-432.
    5. Marine Combe, Rafael Sanjuán (2014). Variation in RNA virus mutation rates across host cells. PLOS Pathogens, 10: e1003855.