‘It’s a super-cool study’ Salmonella took down the Aztecs

Eye herpes is a real thing.

I got it in 1984.

Probably from my ex roomate’s towel.

I was so sick for two weeks, although I did manage to crawl out of bed for a Neil Young show in Toronto (part of the International Harvesters tour) but then felt so sick afterwards I went home to Brantford.

One of my parent’s neighbours was my evy doctor, so I was in for a regular check-up and he detected it immediately.

Put me on some Acyclovir, which had just come out, and I was cured in no time.

Or temporarily. Viruses don’t go away.

We’re all hosts on a viral planet.

Mine has come back, in the form of a cold sore, probably because of the stress of buying a new house in an over-heated real-estate market and not selling ours.
I went to the chemist, got some drugs that aren’t really working, but at least I had that option.

Imagine 600 years ago, when Cortez from Spain dances across the water to what is now Mexico and there’s no chemist down the road.

Ewen Callaway of Nature writes one of the worst epidemics in human history, a sixteenth-century pestilence that devastated Mexico’s native population, may have been caused by a deadly form of salmonella from Europe, a pair of studies suggest.

In one study, researchers say they have recovered DNA of the stomach bacterium from burials in Mexico linked to a 1540s epidemic that killed up to 80% of the country’s native inhabitants. The team reports its findings in a preprint posted on the bioRxiv server on 8 February.

This is potentially the first genetic evidence of the pathogen that caused the massive decline in native populations after European colonization, says Hannes Schroeder, an ancient-DNA researcher at the Natural History Museum of Denmark in Copenhagen who was not involved in the work. “It’s a super-cool study.”

In 1519, when forces led by Spanish conquistador Hernando Cortés arrived in Mexico, the native population was estimated at about 25 million. A century later, after a Spanish victory and a series of epidemics, numbers had plunged to around 1 million.

The largest of these disease outbreaks were known as cocoliztli (from the word for ‘pestilence’ in Nahuatl, the Aztec language). Two major cocoliztli, beginning in 1545 and 1576, killed an estimated 7 million to 18 million people living in Mexico’s highland regions.

“In the cities and large towns, big ditches were dug, and from morning to sunset the priests did nothing else but carry the dead bodies and throw them into the ditches,” noted a Franciscan historian who witnessed the 1576 outbreak.

There has been little consensus on the cause of cocoliztli — although measles, smallpox and typhus have all been mooted. In 2002, researchers at the National Autonomous University of Mexico (UNAM) in Mexico City proposed that a viral haemorrhagic fever, exacerbated by a catastrophic drought, was behind the carnage2. They compared the magnitude of the 1545 outbreak to that of the Black Death in fourteenth-century Europe. 

In an attempt to settle the question, a team led by evolutionary geneticist Johannes Krause at the Max Planck Institute for the Science of Human History in Jena, Germany, extracted and sequenced DNA from the teeth of 29 people buried in the Oaxacan highlands of southern Mexico. All but five were linked to a cocoliztli that researchers think ran from 1545 to 1550.

Ancient bacterial DNA recovered from several of the people matched that of Salmonella, based on comparisons with a database of more than 2,700 modern bacterial genomes.

Further sequencing of short, damaged DNA fragments from the remains allowed the team to reconstruct two genomes of a Salmonella enterica strain known as Paratyphi C. Today, this bacterium causes enteric fever, a typhus-like illness, that occurs mostly in developing countries. If left untreated, it kills 10–15% of infected people.

It’s perfectly reasonable that the bacterium could have caused this epidemic, says Schroeder. “They make a really good case.” But María Ávila-Arcos, an evolutionary geneticist at UNAM, isn’t convinced. She notes that some people suggest that a virus caused the cocoliztli, and that wouldn’t have been picked up by the team’s method.

Krause and his colleagues’ proposal is helped by another study posted on bioRxiv last week, which raises the possibility that Salmonella Paratyphi C arrived in Mexico from Europe.

A team led by Mark Achtman, a microbiologist at the University of Warwick in Coventry, UK, collected and sequenced the genome of the bacterial strain from the remains of a young woman buried around 1200 in a cemetery in Trondheim, Norway. It is the earliest evidence for the now-rare Salmonella strain, and proof that it was circulating in Europe, according to the study. (Both teams declined to comment on their research because their papers have been submitted to a peer-reviewed journal – good for them, dp).

“Really, what we’d like to do is look at both strains together,” says Hendrik Poinar, an evolutionary biologist at McMaster University in Hamilton, Canada. And if more ancient genomes can be collected from Europe and the Americas, it should be possible to find out more conclusively whether deadly pathogens such as Salmonella arrived in the New World from Europe.

Herpes for all in Australia: First the carp — THE CARP – now turtles

Following an impassioned speech by Australian deputy PM Barnaby Joyce (right, not exactly as shown) on government plans to deliberately infect invasive carp with herpes, an increasing number of green sea turtles on barnaby.jonesAustralia’s Great Barrier Reef, with pollution being investigated as the prime culprit.

The animals have a turtle-specific herpesvirus that causes fibropapillomatosis – a condition in which disfiguring tumours grow on the eyes, flippers, tail, shell or internal organs.

“The tumours are benign but can grow up to 30 centimetres in size and block the turtles’ vision, says Karina Jones of James Cook University in Townsville, Australia. “This means they can’t find food or see predators or boats.”

Turtles with tumours are also more vulnerable to other infections, she says. “Severely affected turtles are quite skinny and have other pathogens affecting them – that’s why they die.”

The unpublished results of surveys by Jones’s team this year show that herpesvirus is most prevalent within a narrow stretch of Cockle Bay at Magnetic Island, a popular tourist destination in the middle of the reef. Roughly half the turtles in this hotspot have fibropapillomatosis, compared with less than 10 per cent of turtles sampled across the rest of Cockle Bay.

The cause remains unclear, but environmental contaminants are at the top of the suspect list. “We see these tumours in turtles in very localised hotspots around the world where there is heavy human activity,” says Jones.

Herpes, hepatitis A, swine flu — beer pong transmits disease?

No beer pong? What is college life without beer pong?

Last year, some publication at the University of California at Los Angeles – UCLA – warned students that beer pong, a communal drinking game, could be a source of infectious disease like herpes.

The N.Y Times reports tomorrow that students at Rensselaer Polytechnic Institute in Troy, N.Y., are being asked to refrain from playing beer pong after an outbreak of illness that officials feared might be swine flu.

The story notes that what used to be O.K. is not anymore, as the flu has ushered in new standards of etiquette that can be, in turns, mundane, absurd and heartbreaking.

Heartbreaking and beer pong. College life is tragic.