Puma poo: The oldest parasite DNA ever recorded

The oldest parasite DNA ever recorded has been found in the ancient, desiccated faeces of a puma.

A team of Argentinian scientists from the National Council of Scientific and Technical Research (CONICET) made the discovery after studying a coprolite taken from a rock-shelter in the country’s mountainous Catamarca Province, where the remains of now extinct megafauna have previously been recovered in stratigraphic excavations.

Radiocarbon dating revealed that the coprolite and thus the parasitic roundworm eggs preserved inside dated back to between 16,570 and 17,000 years ago, towards the end of the last Ice Age.

At that time, the area around the shelter at Peñas de las Trampas in the southern Andean Puna was thought to have been wetter than today, making it a suitable habitat for megafauna like giant ground sloths, and also smaller herbivores like American horses and South American camelids which the pumas may have preyed on.

Ancient mitochondrial DNA analysis was used to confirm the coprolite came from a Puma (Puma concolor) and that the eggs belonged to Toxascaris leonina, a species of roundworm still commonly found in the digestive systems of modern day cats, dogs and foxes.

The study, published in the journal Parasitology, explains that the extremely dry, cold and salty conditions which took hold at the Peñas de las Trampas site since the onset of the Holocene would have helped to reduce the breakdown of the DNA, allowing it to be preserved.
Led by Romina Petrigh and Martín Fugassa, the study was carried out by an interdisciplinary team including archaeologists and biologists and is part of a project that views ancient faeces as important paleobiological reservoirs.

Dr Petrigh, from the National University of Mar del Plata and CONICET, said: “While we have found evidence of parasites in coprolites before, those remains were much more recent, dating back only a few thousand years. The latest find shows that these roundworms were infecting the fauna of South America before the arrival of the first humans in the area around 11,000 years ago.”

For Dr Petrigh, the findings also cast light on both the past and the present. She said: “This work confirms the presence of T. leonina in prehistoric times, presumably even before that of humans in the region, and it represents the oldest record in the world. The common interpretation is that the presence of T. leonina in American wild carnivores today is a consequence of their contact with domestic dogs or cats, but that should no longer be assumed as the only possible explanation.

Parasites in poop fossils reveal the crappiness of ancient human hygiene

Sarah Sloat of Inverse reports you can learn a lot from poop. These days, scientists look at people’s feces to figure out their diets and what type of drugs they’re partying with. According to a study released Wednesday, ancient poop is just as revealing. In PLOS One, researchers report that they found a bunch of parasite eggs in feces piled up in ancient latrines, and that this fantastically gross endeavor has provided clues into the lifestyles of humans that lived thousands of years ago.

Ancient latrines found in Bahrain, Jordan, Denmark, the Netherlands, and Lithuania are the focus of the new paper, authored by a team of Danish and Dutch scientists. The samples of ancient waste range significantly in age, with the oldest, found in Bahrain, dating to 500 B.C. to the most recent, found in the Netherlands, dating to 1700 A.D. Microscopy techniques allowed them to pinpoint parasite eggs within the old poop, and DNA analysis of those parasites revealed not only what these humans ate but also the animals they interacted with and the parasites that plagued their stomachs.

“Using a novel approach of applying shotgun sequencing on ancient parasite eggs that have been purified by filtering, we have obtained a new and much more detailed insight into parasitic infections of human populations of the past,” the authors write.

When parasitic worms infect an animal, they lay eggs in the intestine, which are then later plopped out when that animal defecates. The scientists had at first reasoned that there were several ways the eggs could have gotten into the poop: They might have been spread from human to human, passed to humans from animal hosts, or introduced through the consumption of already infected animals.

The team’s analysis showed that most of the parasite DNA came from parasites that spread from human to human. The second most common parasite came from a species that’s spread when people eat raw or undercooked fish and pork.

Via shotgun sequencing, the scientists reconstructed the mitochondrial genomes of some of the parasites. Doing this revealed the species of parasites lurking in the ancient poop, which included the giant roundworm (Ascaris lumbricoides) and human whipworm (Trichruis trichiura). While humans, especially those in Europe, were commonly infected with intestinal worms until the last century, today roundworm and whipworm are fortunately only highly prevalent in countries with low levels of sanitation, insufficient water refinement, and animals that live close to humans.

Their analysis also turned up parasites known to infect sheep, horses, dogs, pigs, and rodents, indicating that the humans who used these latrines lived in close proximity to those animals, with their feces ending up in the same dump. Some poop samples really let the researchers dig into the details of the lives of their makers: For example, feces harvested from the Danish samples, dated from 1018 to 1400 A.D., hints that those ancient people dined on fin whales, roe deer, and hares. Meanwhile, plant DNA found in the feces from North European latrines dated to the same period shows that the veggies of choice were cabbages and buckwheat.