PLoS Biol. https://doi.org/10.1371/journal.pbio.2004108 (2018)

Mouse experiments are conventionally done with tightly controlled environmental and microbiological parameters; however, this probably does not capture the entire complexity of host–pathogen interactions. In PLoS Biology, Graham and colleagues try to address this shortfall in understanding by using conventional C57BL/6 mice kept in the laboratory together with those in semi-natural outdoor conditions (protected from predation but otherwise fully exposed to the environment). The ‘wild’ mice show greater diversity of the microbiota and, when experimentally infected with Trichuris muris, develop a greater burden of this nematode. Uninfected ‘wild’ mice have elevated baseline type 2 immune responses but, unexpectedly, develop a more robust type 1 immune response after being infected with T. muris. This type 1 skewing is inefficient in clearing nematode infections and probably contributes, at least in part, to the greater nematode parasite burden.