Every second with newly discovered intestinal virus

Until now unknown intestinal virus discovered: Every second person carries it

07/27/2014

Researchers have discovered a hitherto unknown intestinal virus, which is apparently as old as humanity itself. Every second person should carry it in itself. The new findings of the scientists could possibly help in the future to treat diseases such as diabetes or obesity.

Virus as old as humanity itself
Although apparently as old as humanity itself, scientists have just discovered a previously unknown gut virus. Apparently half of the world's population carries the virus called crAssphage. It apparently infects certain intestinal bacteria, such as a team around Bas Dutilh from Radboud University Hospital Nijmegen in the Netherlands and Robert Edwards from San Diego State University in the state of California in the journal „Nature Communications“ (Source) reports. Above all, the discovery shows how little is known so far about the human microbiome - the human colonizing microorganisms.

Intestinal flora with great influence on health
Researchers have been looking for some years for microorganisms that colonize humans and especially the intestine. In addition to bacteria, these include viruses that specifically infect intestinal bacteria. Numerous studies have shown that the intestinal flora has a major impact on health and can play an important role in the risk and course of disease. Experts therefore advise repeatedly to build up intestinal flora, so as to contribute to strengthen the immune system. The researchers came rather by chance on the trail of the now discovered virus when they stool samples of initially twelve humans - four identical female twin pairs and their mothers - examined for genetic material of viruses. The researchers noticed an accumulation of virus DNA, which covered 97,000 base pairs and all had the same in common.

Half of humanity carries virus
Although matching against directories of known viruses failed to yield any results, DNA sequences were abundantly found in databases, including the Human Microbiome Project (HMP) of the US Department of Health (NIH). 99.9 percent of the genetic sequences found were from samples from the human intestine. Scientists believe that half of all people worldwide carry the virus. „We found it more or less in every population we looked at“, Edwards said in a press release from his university. „As far as we can tell, it's as old as humanity.“

Bacteria are linked to diabetes and obesity
Because of the specific virus proteins, the researchers assume that CrAssphage is one of the bacteriophages - viruses that infect bacteria and archaea to multiply there. It probably inhabits intestinal bacteria from the group of Bacteroidetes, which are associated with obesity and diabetes. It still needs to be investigated if and how the virus contributes to it. Bacteroidetes bacteria were next to Firmicutes bacteria in the focus of a study by the US University of California at Berkeley, the results of which were published a few months ago. Accordingly, people with a higher proportion of Firmicutes in the intestine are more likely to gain weight. Even older studies have shown that the likelihood of morbid overweight (obesity) increases with increasing proportion of Firmicutes and dwindling proportion of Bacteroidetes bacteria.

Unknown widespread intestine inhabitants
As the authors of the current study emphasize, it shows in principle that even widespread intestinal dwellers can still be unknown. „It is not uncommon to find and find a new virus“, so Edwards. „But it is very unusual to find one that so many people have in common. It's very strange that it stayed under the radar for so long.“ (Ad)