animal host 7,064 host-associated 7,064 digestive tract 7,050 intestine 6,773 mammalian host 6,407 human host 3,610 industrialized 2,586 adult 1,796 child 597 rural 557 non-industrialized 481 urban 393 rumen 341 elderly 281 infant 249 traditional agriculturalist 143 adolescent 115 hunter-gatherer 106 anthropogenic 31 agriculture 28 ancient microbiome 13 terrestrial 9 urogenital tract 7 full term birth 5 built environment 5 aquatic 5 marine 4 soil 4 wastewater 1 medium temperature 1 sewage 1