Tag Archives: feces

The origin of feces (aka shit happens)

The archaeological record is littered with feces, a potential goldmine for insights into ancient health and diet, parasite evolution, and the ecology and evolution of the microbiome. The main problem for researchers is determining whose feces is under examination. A recent study published in the journal PeerJ, led by Maxime Borry and Christina Warinner of Max Planck Institute for the Science of Human History (MPI-SHH), presents “CoproID: a reliable method of inferring sources of paleofeces.”

After thousands of years, the source of a particular piece of feces can be difficult to determine. Distinguishing human and dog feces is particularly difficult: they are similar in size and shape, occur at the same archaeological sites, and have similar compositions. In addition, dogs were on the menu for many ancient societies, and our canine friends have a tendency to scavenge on human feces, thus making simple genetic tests problematic, as such analyses can return DNA from both species.

Shit happens

H35 (Ash pit number 35) coprolites from Xiaosungang archaeological site, Anhui Province, China © Jada Ko, Courtesy of the Anhui Provincial Institute of Cultural Relics and Archaeology

In order to access the insights contained within paleofeces, the researchers developed coproID (coprolite identification). The method combines analysis of ancient host DNA with a machine learning software trained on the microbiomes within modern feces. Applying coproID to both newly sequenced and previously published datasets, the team of researchers from the MPI-SHH, Harvard University, and the University of Oklahoma were able to reliably predict the sources of ancient feces, showing that a combination of host DNA and the distinct colonies of microbes living inside humans and dogs allow their feces to be accurately distinguished.

Classification capability provides insights into digestive health

“One unexpected finding of our study is the realization that the archaeological record is full of dog poop,” says Professor Christina Warinner, senior author of the study. But Warinner also expects coproID to have broader applications, especially in the fields of forensics, ecology, and microbiome sciences.

The ability to accurately identify the source of archaeological feces enables the direct investigation of changes in the structure and function of the human gut microbiome throughout time, which researchers hope will provide insights into food intolerances and a host of other issues in human health. “Identifying human coprolites should be the first step for ancient human microbiome analysis,” says the study’s first author, Maxime Borry.

“With additional data about the gut metagenomes of non-Westernized rural dogs, we’ll be better able to classify even more ancient dog feces as in fact being canine, as opposed to ‘uncertain,’” Borry adds. As the catalog of human and dog microbiome data grows, coproID will continue to improve its classifications and better aid researchers that encounter paleofeces in a range of geographic and historical contexts.

Source:  Max Planck Institute for the Science of Human History

Canine companions and the lure of inattentively pooping in public

The title of this post is unashamedly taken from an article in the journal Environmental Sociology.

Dog poop flagged for research

Photo by Matthias Gross

This article is a study, primarily focused on European nations, and the patterns of owners who do/do not clean up after their dog poops.

The author observed that people are more likely to clean up after their dog when there are people around to watch.

I’ll let you read it for yourself…

The study’s (published) conclusion is:

This exploratory study thus suggests that observing activities and strategies of defecating may provide new insight into human–animal relationships by exploring the role of droppings. An important prerequisite for successfully displaying poop and for diverting attention away from the fact that dog poop is increasingly to be seen in public is that the actors involved are skillful enough to attest to nonknowledge about the production of excrements by their best friends.

Kathleen Crisley, specialist in dog massage, rehabilitation and nutrition/food therapy, Canine Catering Ltd, Christchurch, New Zealand

Other blog posts about dog poop include:

Dog waste and waterway contamination

Credit: Ryan McVay/Photodisc/Thinkstock

Credit: Ryan McVay/Photodisc/Thinkstock

Americans love their dogs, but they don’t always love to pick up after them. And that’s a problem. Dog feces left on the ground wash into waterways, sometimes carrying bacteria — including antibiotic-resistant strains — that can make people sick. Now scientists have developed a new genetic test to figure out how much dogs are contributing to this health concern, according to a report in the ACS journal Environmental Science & Technology.

Orin C. Shanks, Hyatt C. Green and colleagues explain that our waterways are susceptible to many sources of fecal contamination, including sewage leaks and droppings from farm animals and wildlife. Contamination from dog feces is a concern because it can harbor antibiotic-resistant strains of E. coli and other bacteria and parasites that can infect humans — and there are nearly 70 million domesticated dogs in the U.S. Scientists have had few tools to determine the extent to which waste from dogs is adding to the pathogens in rivers, lakes and beachfront surf. Current methods look for certain genes from gut bacteria that end up in dog feces. However, this is not foolproof — the microbiota of humans and the canine pets they live with often overlap, making the analysis complicated. So Shanks’ team set out to create a more specific test.

The researchers developed a new genetic testing method to specifically detect canine fecal contamination in water. They identified 11 genetic markers that were common among most of the dog samples but missing from the human ones. To determine whether their method would work for real-world monitoring, they sampled storm water from a rain garden where people often walk their dogs. The technique successfully detected some of the same markers they had identified as evidence for canine waste.

Source:  ACS news service

UK research supports worming and cleaning up after your dog

Researchers at the University of Bristol’s School of Veterinary Sciences have published their research, which supports the need for ongoing worming of dogs and the need for owners to clean up their dog’s poo.

At issue is the parasitic worm, Toxocara, which are a rare cause of disease in humans, responsible for occasional cases of abdominal pain, loss of sight, and potentially asthma and epilepsy.

Using data from the University, the researchers estimated relative contributions of dogs and the other hosts of the parasites, cats and foxes.   With the help of additional information from a previous study, the researchers estimated that nearly four tonnes of dog waste are produced in Bristol each day and nearly 1,000 tonnes throughout the UK.

Given that each adult female worm can lay 12,500 eggs or more per day, this equates to around 3.7 billion eggs shed per day within the city of Bristol.

“These results are not all that surprising but they are likely to differ widely between places. We provided a method for estimating different sources of contamination with Toxocara eggs anywhere in the world.  This will hopefully help locally appropriate control measures to be put in place. The data also provides a baseline against which future changes can be measured, as we currently lack any good evidence of how effective steps such as anti-fouling legislation are in reducing egg load and human disease” says Dr Eric Morgan the lead author of the paper.

The research team’s findings have been published in the journal Veterinary Parasitology.

Source:  University of Bristol media statement