Co‐infections mask pathogen‐specific associations with the gut microbiota in wild voles

Abstract

Animals and plants harbour complex suites of microbes that span the parasitism-mutualism continuum. To date, microbiomes have largely been studied in the context of their interactions with host biology (e.g. host diet or genotype), yet interactions between microbes themselves have profound consequences for host fitness (Gould et al., 2018), disease progression (O'Keeffe et al., 2021), and pathogen evolution and emergence (Drew et al., 2021;Frederickson & Reese, 2021). Pathogenic microbes are particularly important for shaping interaction networks because they are often uniquely able to suppress competitors (Amaro & Martín-González, 2021) and can hijack the host immune system in a way that affects target and non-target microbes (Kamada et al., 2013). Among studies that characterize interactions between commensal and pathogenic microbes, most explore the effect of single pathogens. In nature, however, co-infections with multiple pathogens are the rule rather than the exception (Hoarau et al., 2020). Generalizing microbial interactions in the face of such complexity remains a major challenge, yet is essential to advance our understanding of how host-associated microbiomes shape host ecology and evolution.In their recent publication in the Journal of Animal Ecology, Brila et al. (2022) investigate associations between co-infecting pathogens and commensal gut microbes in wild bank voles Myodes glareolus. The authors pair surveillance data on four systemic pathogenic microbes (two bacterial, one protozoan, and one viral) with faecal