Wetenschap - 9 september 2016

Viruses play a role in gut health too

Rob Ramaker

Our intestinal flora consist not just of bacteria, but of viruses as well. In colorectal patients the virus community proves to be disturbed. This suggests that viruses too are crucial to intestinal health, suggest microbiologists from Wageningen and the United States in PNAS.

Photo: Filip Bunkens

It has become increasingly clear over recent years that bacterial communities influence the health of our intestines. The presence of ‘good’ microbes is important for a normal metabolism as well as for resistance to disease and mental health. In patients with chronic inflammation of the gut, obesity and diabetes, these gut flora are often disturbed. They often improve after faecal transplants, which provide them with a healthy set of bacteria.

As well as bacteria, our intestines also house large numbers of viruses. These are smaller and inhabit a gray area between living and non-living. In earlier studies scientists found few similarities in virus communities from one person to the next. But the work of professor of Microbiology Willem de Vis and his colleagues changes this picture.

They discovered that there is in fact a core group of viruses that can be found in many people’s systems. The team found 23 viruses which half of their 64 test subjects had in common. And a further group of viruses was common to a substantial minority. What is more, it was precisely in people with Crohn’s disease and ulcerous colitis that this community was disturbed. And that suggests that the viruses, in combination with the bacteria present in our bodies, contribute to intestinal health.

The microbiologists were able to find these similarities now because of their approach. Instead of studying the entire contents of the gut, they fished out as many virus particles as possible from two test subjects. Then all the DNA of these viruses was analysed and compared with that found in other test subjects. 

This result does not translate directly into ‘virus treatments’, warns De Vos, although research on that is already going on.