Pathogen genomes and microbiome data highlight the role of humans as dispersers of emerging infectious diseases
Zoonotic diseases are defined by the spread of pathogenic microorganisms from animals to humans. In this work we used Campylobacter fetus, which causes venereal infections in cattle and systemic infections in humans, as a model to study the evolutionary dynamics of zoonotic diseases. To date it is assumed that human infections with C. fetus are caused by the consumption of contaminated products of animal origin. However, by applying comparative genomics analyses and mining human gut microbiome data, we propose that C. fetus is a pathobiont: a commensal bacterium in normal conditions that can express a pathogenic phenotype under an altered homeostasis, such as during immunosuppression. These results hack a general paradigm about the dynamics of zoonotic diseases, considering that we suggest C. fetus is an original member of the human gut microbiota and then host jumped during cattle domestication to evolve and adapt as a bovine pathogen. C. fetus can be a needle in a vastly unexplored haystack, but is enough to demonstrate that the one health concept should not only consider humans as receptors but also as potential dispersers of pathogenic microorganisms that can harm other animals.
This international effort was leaded by Gregorio Iraola, researcher at Institut Pasteur in Montevideo (Uruguay), in collaboration with the Wellcome Trust Sanger Institute (UK). Also, both the Faculty of Sciences and the Faculty of Medicine from the University of the Republic in Uruguay were directly involved. Additionally, researchers from 15 different countries (including 3 from Latin America) provided their strains from local collections to include in the study.
Iraola G, et al. Distinct Campylobacter fetus lineages adapted as livestock pathogens and human pathobionts in the intestinal microbiota. Nat. Commun. 2017. 8(1):1367.
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