host-associated 485 animal host 485 digestive tract 482 intestine 482 mammalian host 415 human host 393 industrialized 295 infant 132 adult 123 child 97 full term birth 49 urban 32 elderly 23 rural 14 non-industrialized 9 adolescent 6 insect host 3 terrestrial 1 agriculture 1 cropland 1 anthropogenic 1 hunter-gatherer 1 soil 1