animal host 15,038 host-associated 15,038 digestive tract 14,905 intestine 14,828 mammalian host 14,791 human host 14,079 industrialized 10,773 adult 4,720 infant 3,620 child 1,465 urban 1,347 elderly 922 rural 772 non-industrialized 728 full term birth 631 preterm birth 308 adolescent 261 urogenital tract 122 anthropogenic 120 traditional agriculturalist 91 rumen 79 wastewater 75 aquatic 75 mouth 74 saliva 72 sewage 61 built environment 51 terrestrial 49 insect host 38 hospital 29 hunter-gatherer 21 low temperature 16 skin 14 medium temperature 9 fermented food 9 food 9 ancient microbiome 9 agriculture 5 wetland 2 lentic 2 paludal 2 soil 2 very low temperature 2 air 1 negative control 1 anaerobic 1 sludge 1