‘Pooh sticks’ is the name of the game in which people (and other animals such as bears, kangaroos, and donkeys (!)) drop sticks into a stream that flows under a bridge and see whose stick emerges first from beneath its down-stream side. Despite being taken seriously – it has proper rules, and competitive World Championships – that’s far too frivolous and not worthy of a Plant Cutting (though it does feature sticks, which are small tree branches so has a legitimate plant connection for this blog site).
Rather, this item showcases a much more serious, sober, scientific mention of poo [sic] sticks. These poo sticks are quite literally sticks that were used to clean faeces – ‘poo’ in English – from the anuses (ani? Never sure what is the correct plural of these orifices) of humans after they have defaecated. These euphemistically termed ‘personal hygiene sticks’ – a hand-held piece of bamboo or wood with strips of cloth on the end – were used in a way similar to toilet paper in other places or times. And, as with their sometimes quilted and perfumed 21st century stationery equivalent, the sticks were discarded in latrine areas after use. But, far from being the useless detritus of a bygone age, these artifacts contain valuable clues to the stick user’s health.
Examining these ancient anal artefacts, Hui-Yuan Yeh et al. provide evidence for the human transmission of various diseases along the Silk Road, the extensive land-based communication and trade routes that ran between East Asia and Europe 2000 years ago. The study site was the town of Dunhuang, a key stopping point on the Silk Road, within China on the eastern edge of the Taklamakan desert.
Although the sample size was rather small – “Seven sticks … [had] … preserved faeces adherent to the cloth. Faeces from 6 sticks was combined to make one sample, while one stick with more faecal matter preserved comprised the second sample” – they found within these scatological souvenirs eggs of human parasites such as roundworm (Ascaris lumbricoides), several tapeworms (Taenia spp.), and Chinese liver fluke (Clonorchis sinensis). Such a (s)catalogue of colonic companions certainly indicates that it was much more than silk and spices that travelled along that ancient highway.
This work adds to 2015’s revelation that the bacterial infection known as the Black Death or the Plague (Yersinia pestis) was repeatedly introduced to Europe from Asia via both land and sea routes of the Silk Road system. Although in that instance it involved non-human mammals such as camels and giant gerbils(!).
At the other end of the alimentary tract is another phytoforensic story that concerns health-checking of primates. One of the greatest threats to survival of great apes in the wild is infectious diseases. A particular risk is their catching human diseases from the close contact with humans that is inherent in such activities as ecotourism. Monitoring the health of the primate populations is therefore an important component of their management and conservation. Usefully, Tierra Smiley Evans et al. have developed a non-invasive sampling methodology whose ‘proof-of-concept’ has been demonstrated for human herpes virus and non-human primate-specific simian foamy virus.
Herpes DNA was detected in plant material that had been bitten off but rejected by the mountain gorilla (Gorilla beringei beringei), which is (critically-) endangered, and foamy virus RNA in material similarly discarded by the golden monkey (Cercopithecus mitis kandti), which is also endangered. Although this technique can only deal with viruses that are shed orally, it adds to the existing range of urine and faecal sampling methodologies thus broadening primate health-monitoring capability. So, and unlike the case for many humans, biting off more than they can chew can be a good thing for these primates.