Virus and microbiota relationships in humans and other mammals: An evolutionary view

Abstract In the last decades, studies have revealed multiple and strong correlations between the host and its commensal microbiota consisting of bacteria, protozoa, fungi and viruses. This associated microbiota can positively or negatively influence the course of a wide range of infections. Here, we review the interactions between the host and its viral microbiota and discuss new paradigms from an evolutionary perspective. The viral adaptation to a microbial environment in a co-evolutionary approach is highlighted, as well as viral cross transmission in the context of the barriers imposed by the indigenous microbiota. In addition to reviewing the host-microbiota-virus relationships, we focus the discussion on microbiota-virus interactions that could be applied to preventive and therapeutic treatments.