British and Chinese researchers from the University of Cambridge and China’s Academy of Social Sciences and Gansu Institute for Cultural Relics and Archaeology were digging in what we call an outdoor latrine at the Xuanquanzhi relay station, an archaeological site in northwestern China that was used as a rest stop along the Silk Road.
This particular rest stop was a large way-station, located on the eastern margins of the arid Tamrin Basin in north-western China. It was built in 111 BC and used until about 109 AD, according to historical records. The Silk Road itself is generally acknowledged to have existed from about 130 BCE to about the mid-1400s.
Cambridge researchers Hui-Yuan Yeh and Piers Mitchell used microscopy to examine the preserved 2,000-year-old feces that still stuck to pieces of cloth wrapped around the ends of “personal hygiene sticks,” used to clean oneself after defecating.
The hygiene sticks themselves were made of wood or bamboo, with a piece of cloth wrapped around one end. “We found that seven of such sticks had preserved feces adherent to the cloth,” Hui-Yuan Yeh and Mitchell, said.
The two researchers found the eggs of four species of parasitic worm (helminths) in the preserved feces: roundworm (Ascaris lumbricoides), whipworm (Trichuris trichiura), tapeworm (Taenia sp.), and Chinese liver fluke (Clonorchis sinensis).
A fluke discovery is monumental
The Chinese liver fluke, which needs wet, marshy areas to complete its life cycle, was of particular interest because it came from a location at least 1,000 miles away. The fluke is most common in Guangdong Province, around 1,240 miles from the site, according to Archaeology.org.
The liver fluke lives in the liver of humans, mainly in bile ducts, and can produce up to 4,000 eggs per day for at least six months. “If an infected person goes to the toilet in fresh water, these eggs gain entry to a suitable snail, which acts as the intermediate host,” the researchers wrote.
The liver flukes life cycle continues when it finds a suitable second intermediate freshwater fish host. “Infection occurs when people eat raw fluke-infested fish,” study leader Mitchell told Discovery News.
The finding of the fluke eggs is a monumental discovery. “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,” says study co-author Hui-Yuan Yeh.
The Silk Road and its impact on everything
The Silk Road or Silk Route was an interconnected network of many trade routes that connected the East and the West, from China to the Mediterranean Sea. Beginning during the Han Dynasty (207 BCE – 220 CE), the road derives its name from the lucrative trade in Chinese silk carried out along its length.
But silk was not what made the road so important to the development of civilizations along its route. It was the trade in commodities, of course, but it was more because of the exchange of ideas, language, customs, technology and culture that we remember the road.
The development of political and economic relationships notwithstanding, the Silk Road is also remembered for helping to spread the bubonic plague, anthrax, and leprosy, according to many researchers, because matching DNA fingerprints of these diseases have been found in China and Europe.
“Until now there has been no proof that the Silk Road was responsible for the spread of infectious diseases. They could instead have spread between China and Europe via India to the south, or via Mongolia and Russia to the north,” says Mitchell.
This interesting study, “Early evidence for travel with infectious diseases along the Silk Road: Intestinal parasites from 2000 year-old personal hygiene sticks in a latrine at Xuanquanzhi Relay Station in China,” was published on July 22, 2016 in the online Journal of Archaeological Science: Reports.