host-associated 11,757 animal host 11,756 digestive tract 11,740 mammalian host 11,471 intestine 11,362 human host 9,644 industrialized 7,529 adult 3,864 infant 1,147 child 1,146 urban 1,022 rural 1,010 non-industrialized 937 elderly 704 mouth 415 saliva 301 adolescent 246 full term birth 187 rumen 186 aquatic 102 preterm birth 89 traditional agriculturalist 79 hunter-gatherer 67 anthropogenic 64 terrestrial 52 airways 44 wastewater 43 fresh water 37 low salinity 27 sewage 26 insect host 17 agriculture 17 ancient microbiome 16 subsurface 16 groundwater 16 soil 16 lentic 13 medium temperature 13 contaminated 13 marine 12 lacustrine 11 sludge 10 benthic 6 built environment 6 sediment 6 mine 5 hospital 4 low temperature 4 cropland 4 anaerobic 4 stream 4 tundra 4 wetland 2 ice 2 paludal 2 very low temperature 2 lake bed 2 waste 2 alkaline 2 plant host 1 food 1 permafrost 1 high salinity 1 fermented food 1 acidic 1 phyllosphere 1 urogenital tract 1