Toilet Paper? No, Toilet Sticks
Two thousand years ago, travelers on the Silk Road cleaned themselves with sticks after using the toilet. No paper, just sticks with cloth wrappers.
Researchers studied these toilet sticks to finally prove some long-debated theories about travel and how diseases spread. They discovered signs of several parasites on personal hygiene sticks found at an ancient latrine at Xuanquanzhi along the east edge of the Tarim Basin. Some were species that needed wet marshy areas for parts of their life cycles, suggesting that people from moist areas in eastern or southern China must have traveled through that region for trade or government business.
These personal hygiene sticks offer proof for some old theories about the spread of disease along ancient trade routes. The Silk Road has been blamed for the spread of bubonic plague, leprosy, anthrax, and other dreaded diseases between East Asia, the Middle East, and Europe. However, there has been little evidence supporting those theories of disease transmission.
The Personal Hygiene Sticks
The sticks were discovered in 1992, and are stored at the Gansu Institute of Cultural Relics and Archaeology. They are made of wood or bamboo wrapped with cloth. Ancient Chinese texts described hygiene sticks for wiping yourself. They sometimes call them bamboo slips.
Hygiene sticks had been found before. What was different about these? Preserved feces were attached to the cloth! These feces contained eggs of parasites: whipworm, roundworm, tapeworm, and Chinese liver fluke.
The Chinese liver fluke (or Clonorchis sinensis) was the most remarkable parasite discovery given the location. This flatworm has been an endemic parasite of the marshy areas of southern China for thousands of years. It is believed to be the third most prevalent worm parasite.Visiting
The fluke needs a wet marshy environment for part of its life cycle. Like many parasites, it has a complex life cycle.
A fluke matures in the bile ducts of the host's liver and produces up to 4000 eggs every day for up to six months. Those eggs leave the body in feces.
If the person's feces go into fresh water, the eggs are eaten by a snail. The larva develop in that first intermediate host, first into a motile form called the miracidium and then into a sporocyst, an elongated sac.
The sporocyst produces more sporocysts or rediae, a larval form with an oral sucker. These asexually reproduce, greatly multiplying the numbers while producing either more rediae or free-swimming cercaria.
The redia actively bore their way out of the snail into its freshwater environment. They find a freshwater fish, such as the common carp, grass carp, or other fish common to those waters. They bore their way into it and become parasites of that new host.
Within the muscle tissue of the fish, the cercaria develops further. It creates a protective cyst.
The fish is eventually eaten by a human or other fish-eating mammal, the fluke's ultimate hosts. The acid-resistant cyst allows the metacercaris to reach the small intestine without being harmed by the digestive fluids in the stomach. It then navigates toward the liver, where it feeds on blood and transforms into its stage of sexual reproduction.
A 2009 study estimated that about 1.8% of people in Guangdong Province in south China were infected with the Chinese liver fluke. Most cases today occur in Guangdong Province.
Chinese liver flukes simply could not survive in the area where these sticks were found.
They must have arrived as parasites of travelers coming from southeastern China.
The Silk Road and the Desert Relay Station
The Silk Road was a network of some 6500 kilometers of caravan paths across Asia. It allowed merchants, pilgrims, monks, and adventurers to travel from the Pacific coast of China to the Mediterranean Sea. It was a prominent route during China's Han Dynasty, from 202 BCE to 220 CE.
The ancient city of Palmyria was near the western end of the Silk Road. Its merchants established colonies along the Silk Road when their city reached the peak of its power in the 260s and 270s CE, under its King Odaenathus and then Queen Zenobia.
Xuanguanzhi was a large relay station along the Silk Road in northwestern China. Xuanguanzhi was in Gansu Province, along the 1000-km-long Hexi Corridor connecting the the Tarim Basin at its northwest end to the Yellow River at its southeast end. It ran between the Gobi Desert, the Taklamakan Desert, the Qilian Mountains, and the Beishan Mountains. Headed west, the Silk Road split near Xuanguanzhi to pass around the Taklamakan Desert to its north and south.
Ancient documents, backed up by excavations at the site, show that the Xuanguanzhi relay station was built in 111 BCE and operated until 109 CE. The final part of the name indicates that it was a post where official riders changed horses. The postal relay system carried messages on horses between local governments and the imperial court in central China. Posts like these maintained horses for the postal system, and they also hosted travelers.
Now the town of Dunhuang is here, and the site of Xuanquanzhi is designated as a Major Historical and Cultural Site Protected at the National Level. Dunhuang continued to be a major hub of commerce and travel along the Silk Road through the Sui (581-618) and Tang (618-907) dynasties. The early Buddhist monks from India arrived in China by the first century CE, and a large Buddhist community developed here. The Silk Road brought Buddhism to China and helped to spread it throughout Asia. Jewish, Christian, and Manichaean artifacts and writings have also been found here, indicating the mix of people traveling the Silk Road network.
Some of these people must have brought parasites and left their eggs in the latrine.
Xuanquanzhi is at least 1500 kilometers away from any area where the Chinese liver fluke parasite is endemic today, and it's 2000 kilometers away from Guangdong Province where most current cases are found.
Read the paper for more details: Yeh, H.-Y., et al., "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", Journal of Archaeological Science: Reports (2016), http://dx.doi.org/10.1016/j.jasrep.2016.05.010.