Mount Everest has been preserving climbers’ coughs and sneezes for CENTURIES, study finds

Don’t forget your tissues when you go mountain climbing, because microbes from coughs and sneezes can be preserved in the ice for centuries, a study has found.

Researchers from the University of Colorado Boulder analysed soil samples from Mount Everest, and found microbial DNA associated with humans.

The bacteria these belonged to include Staphylococcus, which is associated with food poisoning and pneumonia, and Streptococcus, which causes sore throats.

Most of the microbes they found were thought to be dormant, but had been conserved in ‘deep-freeze collection zones’ near areas of human activity.

This finding supports the idea that alien life could exist on other frozen planets, the scientists say.

Dr Steve Schmidt, senior author on the new paper, said: ‘We might find life on other planets and cold moons.

‘We’ll have to be careful to make sure we’re not contaminating them with our own.’

In the past, researchers have studied the soil in the coldest regions on Earth, but but have rarely detected significant amounts of human-associated microbes.

Indeed, they have never been able to conclusively identify these microbes in samples collected above 26,000 feet (7.9 km).

But for the new study, published in Arctic, Antarctic, and Alpine Research, the USA-based team analysed soil using state-of-the-art gene sequencing technology.

Their samples were collected from Everest’s South Col during the 2019 National Geographic and Rolex Perpetual Planet Everest Expedition.

This was the most comprehensive scientific expedition to Mount Everest in history, and involved the installation of the two highest weather stations in the world. 

The South Col is the rocky gap between Everest and the Lhotse peak, and the final stop for mountaineers before they begin their journey up the world’s tallest mountain.

Explorers with the expedition journeyed as far away from the camp as possible to collect soil samples, before they were analysed in the laboratory.

Scientists were able to identify almost any active and dormant microbes present in the sample through their DNA, and determine their genetic diversity. 

They were expecting to find some of them, as they have been detected in other extreme, high-elevation locations. 

These are particularly hardy microbes, as they thrive in low temperatures, high UV exposure and with low water availability.

One of them, Naganishia, was by far the most abundant in the South Col samples.

However, they also found unprecedented levels of human-associated microbes left over from the sneezes and coughs of mountain climbers.

‘There is a human signature frozen in the microbiome of Everest, even at that elevation,’ said Dr Schmidt.

Their existence was not surprising, given the amount of adventurers that pass through the South Col and how easily germs get blown about.

Yet their diversity indicted that the microbes were likely dormant, and had not been killed by the harsh, Himalayan conditions. 

This was a shock, because these microbes have evolved to survive in the warm, wet environments inside our noses and mouths.

The researchers say that these could have been left by explorers decades or centuries ago, suggesting the impacts of human activity on the mountain are more withstanding than previously thought.

The authors wrote: ‘Our data suggest that the South Col and other extremely high-elevation environments may be deep-freeze collection points for deposited organisms, including human-borne contaminants that may never leave once they arrive.’