human 10^3 - 10^4: cows and pigs ≤10^7 phages/gram feces
||Fortier LC, Sekulovic O. Importance of prophages to evolution and virulence of bacterial pathogens. Virulence. 2013 Jul 1 4(5):354-65. doi: 10.4161/viru.24498 p.354 left column bottom paragraphPubMed ID23611873
|| Chibani-Chennoufi S, Bruttin A, Dillmann ML, Brüssow H. Phage-host interaction: an ecological perspective. J Bacteriol. 2004 Jun186(12):3677-86 DOI: 10.1128/JB.186.12.3677-3686.2004  Chibani-Chennoufi S et al., Isolation of Escherichia coli bacteriophages from the stool of pediatric diarrhea patients in Bangladesh. J Bacteriol. 2004 Dec186(24):8287-94 DOI: 10.1128/JB.186.24.8287-8294.2004PubMed ID15175280, 15576777
||Primary source  abstract: "A 3-week coliphage survey was conducted in stool samples from 140 Bangladeshi children hospitalized with severe diarrhea."
||P.354 left column bottom paragraph: "Escherichia coli phages dominate (the viral flora), with 10^3–10^4 phages per gram of feces in humans and up to 10^7 in cows and pigs (primary sources), but phages infecting other important commensal bacteria like Bacteroides fragilis and Salmonella spp. have been isolated as well (ref 8)."