The Romans are well known for introducing sanitation technology to Europe around 2,000 years ago, including public multi-seat latrines with washing facilities, sewerage systems, piped drinking water from aqueducts, and heated public baths for washing. Romans also developed laws designed to keep their towns free of excrement and rubbish. However, new archaeological research has revealed that -- for all their apparently hygienic innovations -- intestinal parasites such as whipworm, roundworm and Entamoeba histolytica dysentery did not decrease as expected in Roman times compared with the preceding Iron Age, they gradually increased. 

The latest research was conducted by Dr Piers Mitchell from Cambridge's Archaeology and Anthropology Department and is published today in the journal Parasitology. The study is the first to use the archaeological evidence for parasites in Roman times to assess "the health consequences of conquering an empire".

Dr Piers Mitchell brought together evidence of parasites in ancient latrines, human burials and 'coprolites' -- or fossilised faeces -- as well as in combs and textiles from numerous Roman Period excavations across the Roman Empire. 

Not only did certain intestinal parasites appear to increase in prevalence with the coming of the Romans, but Mitchell also found that, despite their famous culture of regular bathing, 'ectoparasites' such as lice and fleas were just as widespread among Romans as in Viking and medieval populations, where bathing was not widely practiced. 

Some excavations revealed evidence for special combs to strip lice from hair, and delousing may have been a daily routine for many people living across the Roman Empire

Piers Mitchell said: "Modern research has shown that toilets, clean drinking water and removing faeces from the streets all decrease risk of infectious disease and parasites. So we might expect the prevalence of faecal oral parasites such as whipworm and roundworm to drop in Roman times -- yet we find a gradual increase. The question is why?" 

One possibility Mitchell offers is that it may have actually been the warm communal waters of the bathhouses that helped spread the parasitic worms. Water was infrequently changed in some baths, and a scum would build on the surface from human dirt and cosmetics. "Clearly, not all Roman baths were as clean as they might have been," said Mitchell. 

Another possible explanation raised in the study is the Roman use of human excrement as a crop fertilizer. While modern research has shown this does increase crop yields, unless the faeces are composted for many months before being added to the fields, it can result in the spread of parasite eggs that can survive in the grown plants.