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Novel gut virus infects more than half of global population
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A previously unknown bacteriophage called crAssphage, which may play a role in diabetes, obesity and other gastrointestinal diseases, exists in more than half the world’s population, according to research data.
“It’s not unusual to go looking for a novel virus and find one,” Robert A. Edwards, BSc, DPhil, professor of bioinformatics at San Diego State University, said in a press release. “But it’s very unusual to find one that so many people have in common. The fact that it’s flown under the radar for so long is very strange.”
Aiming to identify new viruses in the human gut, Edwards and colleagues analyzed published viral metagenomes from fecal DNA samples of 12 patients. They identified the virus’ genome sequence and its abundance using a cross-assembly software program after which crAssphage was named and confirmed its novelty by unsuccessfully screening for it in a database of known viruses.
Referencing the NIH’s Human Microbiome Project database, researchers used co-occurrence profiling of the crAssphage genome with 404 potential hosts from 151 fecal metagenomes to predict that crAssphage’s bacterial host is from the common phyla Bacteriodetes, which live in the terminal part of the GI tract and are implicated in the link between obesity and the microbiome.
They also screened for crAssphage in public metagenomes from Argonne National Laboratory’s MG-RAST database, and found 235.8 million sequencing reads, 99.9% of which came from human gut metagenomes, that matched crAssphage. This finding indicated its abundance in human feces compared with other environments (P<2.2e–16).
“We’ve basically found it in every population we’ve looked at,” Edwards said in the release. “As far as we can tell, it’s as old as humans are.”
Edwards hopes to further explore the role crAssphage plays in obesity once it is isolated, according to the release, but whether it promotes or suppresses obesity remains unknown.
“This could be a key to personalized phage medicine,” Edwards said. “In individuals, we could isolate your particular strain of the virus, manipulate it to target harmful bacteria, then give it back to you.”
Disclosure: The researchers report no relevant financial disclosures.
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