At least they smelled better. (Alessandra Tarantino/AP)

When the Roman Empire spread across Europe 2,000 years ago, it brought some of the first real sanitation efforts with it. Romanization meant bathing, using toilets and keeping feces out of the streets. But it might not have been the boon to public health that you'd expect.

According to a study published Thursday in the journal Parasitology, Roman toilets – and rotting fish sauce – may have actually made parasites more prolific across Europe.

Cambridge University's Piers Mitchell, a biological anthropologist who studies the evolution of disease throughout history, was inspired by the fact that access to clean water and even simple toilets can drastically improve human health in modern third-world countries. Before the Romans began conquering Europe, there are no signs that anyone else had the sewers, baths and aqueducts that they offered. In analyzing available archeological evidence, Mitchell expected to see some drop in parasites spread by poor sanitation, like roundworm, even if parasites caused by eating certain foods held steady.

Roman latrines from a city in Libya. (Craig Taylor)

"But surprisingly, they didn't drop," Mitchell told The Post. "They stayed roughly the same and then gradually increased." And in addition to the internal parasites (which are detected using their tough, tiny eggs, which remain intact in archeological sites, fossilized feces and soil from human burial sites) Mitchell found evidence that fleas, ticks and body lice remained common pests in Romanized areas.

"It certainly didn't make things any worse," Mitchell said, in the grand scheme of public health. While some parasites can cause potentially fatal illnesses like dysentery, others are harmless if you're getting enough to eat. And folks probably smelled better. But there are a few things that might have made Roman "sanitation" a little gross: For starters, Rome encouraged bathing in public bathhouses. If the water there wasn't kept pristine, it stands to reason that the warm, damp gathering place could actually have given parasites and pests a nice breeding ground.

Mitchell also suspects that the Roman insistence on cleaning the streets of any stray feces might have backfired.

"The overall sanitation package they brought across Europe also included laws about taking all the waste from the street out of town," Mitchell explained. "This probably made the streets smell better, but it also led to the feces being used for soil." We now know that human feces must be composted for months before being used on food crops, lest the fertilizer spread parasite eggs. "The Romans didn't know anything about that, so they may have been reinfecting their population," he said.

Roman fish sauce was a global hit, but, ew. (BBC via YouTube)

One of Rome's gifts to its burgeoning empire was almost certainly bad for health: garum, a sauce made from rotten, raw fish. Mitchell's research suggests that this popular condiment may have helped spread fish tapeworms across Europe. You can find out more about garum in the video below (a clip from the BBC series "The Supersizers...") starting at 13:30.

"It wasn't cooked, and it was put out in the sun to ferment," Mitchell said of the fish sauce. "And this was put into jars and sealed up and taken right across the empire. These tapeworms from Northern Europe could be taken to places where they weren't usually endemic. So you could argue that Romanization actually helped spread certain parasites."

Mitchell plans on studying how other human technologies throughout history influenced public health. Perhaps Roman toilets weren't the only overrated feat of modernity.

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