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.

Roundworm: The parasite on the playground

Amy, Sorenne and I were walking around Nouvea, New Caledonia this morning, and passed a sushi shop.

I said, no, I don’t eat raw fish, I’m not into worms.

If it’s frozen at sea it should control the worms, but that a long supply loop and I got enough problems.

Sorenne said, why would worms live inside us.

I started on an intro microbiology talk, but she soon became more interested in the next shop, despite my efforts to make it sound gross.

Maybe this story from today’s N.Y. Times by Laura Beil will help.

Millions of American children have been exposed to a parasite that could interfere with their breathing, liver function, eyesight and even intelligence. Yet few scientists have studied the infection in the United States, and most doctors are unaware of it.

The parasites, roundworms of the genus Toxocara, live in the intestines of cats and dogs, especially strays. Microscopic eggs from Toxocara are shed in the animals’ feces, contaminating yards, playgrounds and sandboxes.

These infectious particles cling to the hands of children playing outside. Once swallowed, the eggs soon hatch, releasing larvae that wriggle through the body and, evidence suggests, may even reach the brain, compromising learning and cognition.

The Centers for Disease Control and Prevention periodically tracks positive tests for Toxocara through the National Health and Nutrition Examination Survey. The latest report, published in September in the journal Clinical Infectious Diseases, estimated that about 5 percent of the United States population — or about 16 million people — carry Toxocara antibodies in their blood, a sign they have ingested the eggs.

But the risk is not evenly shared: Poor and minority populations are more often exposed. The rate among African Americans was almost 7 percent, according to the C.D.C. Among people living below the poverty line, the infection rate was 10 percent.

The odds of a positive test rise with age, but it’s unknown whether this reflects recent infections or simply an accumulation of antibodies from past encounters.

Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine in Houston, calls Toxocara both one of the most common parasites in the country and arguably the most neglected.

“We know in some cases it is linked to lower intelligence and epilepsy,” he said. “So if you were to look at disadvantaged kids living in poverty who are also doing lower on tests of school performance, what percentage of that can be attributed to this worm?”

While much is still unknown, “there’s enough here to warrant doing a major study on a large number of children.”

At the moment, research into Toxocara among Americans is so lacking that the National Institutes of Health funding website lists no grants to study it. Even many of the most basic questions are unanswered, including how often ingested eggs progress to full-blown infection.

Among the country’s overlooked parasitic infections, “Toxocara is probably the one that affects the broadest range of people,” said Sue Montgomery, lead of the epidemiology team at the parasitic diseases branch of the C.D.C. “Dogs and cats are everywhere. Many of them may carry the parasites.”

Studies indicate that owned pets who receive regular veterinary care rarely carry Toxocara. Poorer neighborhoods bear a disproportionate share of strays. In one survey, 8,700 unowned dogs were said to be roaming parts of Dallas.

A survey of New York City playgrounds, presented at a medical conference last year, sampled 21 parks across the city. Toxocara eggs were found in nine parks. Three quarters of samples taken in the Bronx contained eggs in the larval stage, which are more infectious. No parks in Manhattan had eggs with larvae.

Gonzalo Erdozain: Pick up after pets; windy city clear about zoonoses

Stepping in dog poop is annoying, but the health hazard is unknowingly ingesting or contact with the poop.

While walking around Chicago, I came across this sign that is unique in its clarity: Pet waste transmits disease (right, exactly as shown).

It goes straight to the point and informs the public of the real reason behind the need to clean after our pets in public places.

Dog poop can spread hookworms and roundworms, both of which can infect humans and have severe consequences: ocular larva migraines from roundworms; cutaneous larva migraines from hookworms.