While giardiasis is considered potentially zoonotic, human origin is considered to be the overwhelmingly predominant source based on genotyping. http://www.cfs

While giardiasis is considered potentially zoonotic, human origin is considered to be the overwhelmingly predominant source based on genotyping. http://www.cfsph.iastate.edu/Factsheets/pdfs/giardiasis.pdf http://www.cfsph.iastate.edu/Factsheets/pdfs/giardiasis.pdf All bets are off for other protozoans and bacterii.