The virus among us

Scientists have discovered a previously unknown virus living in the human gut, according to a study in Nature Communications. Exploring genetic material found in intestinal samples, the international team uncovered the CrAssphage virus. They say the virus could influence the behaviour of some of the most common bacteria in our gut. Experts say these types of viruses, called bacteriophages, have been shown to play a role in chronic diseases. Led by a team at San Diego State University in the USA, scientists scoured genetic information stored in three large international databases. They stumbled upon a piece of DNA, some 100,000 letters long, present in more than half of all samples from the gut, and while cross-checking its identity in global directories, they realised it had never been described before. It is not unusual to go looking for a novel virus and find one, but it's very unusual to find one that so many people have in common. The fact it has flown under the radar for so long is very strange. This begs the obvious question: what other bugs could we be hiding inside our bodies?