frog metagenome Targeted loci environmental. gut metagenome

Changes in the early-life microbiota of hosts could affect infectious disease risk throughout life if such disruptions during formative years alter immune system development. Here, by manipulating the microbiota of tadpoles and challenging them with parasitic gut worms as adults, we test whether an early-life disruption of host-associated microbiota affects later-life resistance to infections. Adult frogs with reduced microbial diversity as tadpoles had three times more worms than adults that did not have their microbiota manipulated as tadpoles, presumably because tadpole bacterial diversity was negatively related to parasite establishment in adult frogs. In contrast, adult gut bacterial diversity during parasite exposure was not significantly correlated with parasite establishment in adult frogs. Thus, we demonstrate that an early-life disruption of the microbiota had lasting effects on host resistance to infection, which was likely mediated by its effects on immune system development. Preventing early-life disruption of the host-associated microbiota could be an effective way to induce long-term improvements to health.