Roman toilets didn’t flush parasites

Ancient Rome’s toilets, baths, aqueducts and sewage systems may not have revolutionized public health after all. The proof is in the poop, paleopathologist Piers Mitchell of the University of Cambridge argues online January 8 in Parisitology.

He surveyed parasite numbers in latrines, mummified remains and fossilized feces before and after the implementation of Roman 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 crops and rarely changed the water at some public bathhouses.

Fish tapeworm was even more common in Roman times than in the earlier 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.