Roman toilets didn’t flush parasites

Ancient Rome’s toilets, baths, aqueducts and sewage systems may not have revolutionized public health after all, and the proof is in the poop, Piers Mitchell, an archaeologist at the University of Cambridge, argues January 7 in Parisitology.

Mitchell surveyed parasite numbers from latrine archaeological sites, in mummified remains and in fossilized feces before and after the implementation of Imperial Rome’s hygiene projects. The data suggest that roundworms and other parasites that spread through contact with feces maintained their numbers despite sanitation efforts — perhaps because Romans used human feces to fertilize their crops and rarely changed the water at some public bath houses.

Fish tapeworm was even more common in Roman times that in the Bronze or Iron Ages, which Mitchell attributes to the popularity of fermented fish sauce in ancient Rome. Regular bathing throughout the Empire also appears to have done little to curb populations of ectoparasites like head lice.