A study led by researchers from San Diego State University has detected a virus that is hosted by half the world’s population in their guts, which infects the gut bacteria Bacteroidetes. The virus named crAssphage was discovered accidently when researchers were screening results from the previous studies on gut inhabiting and potential new viruses.
They were working on an experiment in which DNA faecal samples from 12 different individuals were taken to find new clues. It was during this experiment that they noticed a particular cluster of viral DNA in all the samples that were about 97,000 base pairs long. Researchers thereafter, screened the virus against an existing list of known viruses and concluded that it wasn’t known. They further screened the same virus across the database of National Institute of Health’s (NIH) Human Microbiome Project and Argonne National Laboratory’s MG–RAST database and found that the virus was in abundance in samples derived from human faeces.
The viral DNA was located using a technique known as DNA amplification and scientists asserted that its abundance indicates that it is an ancient virus, probably as old as humans themselves. This led to a conclusion that the virus is bacteriophage that infects and replicates inside bacteria. They discovered that bacteriophage proliferates by infecting a common phylum of gut bacteria known as Bacteriodetes.