Ancient Poop Sticks Prove the Silk Road Spread Disease

The Silk Road, an ancient network of trade routes spanning from China to Mediterranean Europe, was once critical to trade and the transmission of ideas between the East and West. It helped turn Buddhism, Islam, and Christianity into truly world religions, satiated the Roman desire for Asian silks and spices, turned Baghdad into a world capital, and if a team of researchers from Cambridge are right, spread infectious diseases across continents.

The team was lead by biological anthropologists Piers Mitchell and Hui-Yuan Yeh, who used microscopy to analyze personal hygiene sticks discovered in a latrine at a once thriving Silk Road relay station in China to determine that the trade route was used to spread disease.

As detailed in Mitchell and Yeh's recent report in the Journal of Archaeological Sciences, these 2000-year old hygiene sticks (basically a stick wrapped in cloth used to wipe one's ass) had traces of preserved feces on them which contained eggs from four types of parasitic worms: roundworm, whipworm, tapeworm and Chinese liver fluke.

"When I first saw the Chinese liver fluke egg down the microscope I knew that we had made a momentous discovery," said Yeh. "Our study is the first to use archaeological evidence from a site on the Silk Road to demonstrate that travelers were taking infectious diseases with them over these huge distances."

The presence of the Chinese liver fluke was "momentous" because it was discovered in a latrine on the border of the Taklamakan desert which is about 1500 kilometers away from its nearest natural environment in China. This suggests that it was brought to the area by traders traveling enormous distances on the Silk Road.

The liver fluke can cause severe abdominal pain, diarrhea, and even liver cancer, and as such the researchers were surprised to find that traders were able to travel such long distances while carrying the parasite.

This is big news, as researchers have previously suggested that other diseases such as bubonic plague, anthrax and leprosy were also transmitted by way of traders on the Silk Road. Until the Cambridge research, however, their assertions lacked robust evidence.

"Until now there has been no proof that the Silk Road was responsible for the spread of infectious diseases," said Mitchell. "They could instead have spread between China and Europe via India to the south, or via Mongolia and Russia to the north. This proves for the first time that travelers along the Silk Road really were responsible for the spread of infectious disease along this route in the past."