Beyond Symbiosis: The Mind‐Bending Role of Microbiomes in Host–Parasite Interactions

This is the authors' abstract. We don't add key points for this paper.

Microbes are ubiquitous and essential components of all living organisms and ecosystems.Host-parasite interactions are increasingly being reframed as multi-partner systems in which both hosts and parasites harbour microbial communities with the potential to modify infection outcomes.In particular, parasite microbiomes, the assemblages of bacteria, viruses and fungi associated with parasites, represent potentially critical, yet often overlooked, determinants of infectivity, development and virulence.Within hosts, gut microbiomes can be highly specific and contribute to multiple aspects of host health, from metabolism to immune development; their composition can also vary markedly among individuals, with effects that extend beyond the gut to immune function and host physiology.Yet we still know surprisingly little about how gut microbiota shape parasite resistance in free-living animals, or whether microbiome effects help explain variation in parasitism across host species.Love et al. (2025) documented opposite-direction parasite outcomes under identical early-life perturbations in two host species.