Scientists have discovered a new virus, which to their amazement, can be found in the gut of about half of all the people worldwide.
Describing their findings in a study published in the journal Nature Communications on July 24, Robert Edwards from the Department of Computer Science at the San Diego State University in California, and colleagues estimated that the newly discovered virus they have called crAssphage is about six times more prevalent than all other bacterial viruses put together, which suggests that the virus is the most abundant that has been discovered so far.
Edwards and colleagues determined that crAssphage is a bacteriophage, a virus that infects a bacterium and replicates inside of it. The newly discovered virus infects common gut bacteria known as Bacteroides.
The virus was discovered after researchers analyzed the DNA found in the fecal samples of 12 individuals, where they discovered a group of viral DNA that is common across the samples. After analyzing DNA sequences in a large database that have taken samples from people living in different continents, the researchers found that the virus is found in 75 percent of fecal samples from people who live in the U.S., Europe and Korea accounting for 1.7 percent of the sequences that the researchers analyzed, or more than six times the prevalence of all other phages put together.
"We identified and validated the ~97 kbp genome sequence of a novel bacteriophage, crAssphage," the researchers wrote. "We show that its genome sequence is highly abundant and ubiquitous in publicly available metagenomes, and predominantly occurs in human faeces."
Edwards said that since some of the samples were taken from a single person, they estimate that the virus can be found in approximately half of the world's population. He also said that the virus appears to be as old as humans and that it is quite strange that such a common virus was undiscovered for a long time.
"It's not unusual to go looking for a novel virus and find one," Edwards said. "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."
Although the function of the bacteria is still unclear, it is suspected to be involved in weight management because of its impact on Bacteroides, which are believed to be associated with obesity and diabetes. The researchers said that they hope to learn more about the role of the virus on obesity.
