The vast virome | Science News

Scientists estimate that 10 quintillion virus particles populate the planet. That’s a one followed by 31 zeros. They outnumber bacteria 10-to-1 in most ecosystems. And they’re ubiquitous in and on humans.

Pérez-Brocal and others are learning that viruses, once seen only as foreign invaders that make people sick, are an integral part of human biology. Some cause major diseases, including influenza, AIDS and some cancers. Others, conversely, may promote health. Some may even help us gauge how well the human immune system works.

The study of people’s resident viruses, known collectively as the human virome, is “a whole new frontier in the understanding of humans,” and could become important for the future of medicine, says Forest Rohwer, an environmental microbiologist at San Diego State University.

Rohwer’s research indicates that viruses are part of the human defense system. Mucus studded with bacteria-infecting viruses called bacteriophage, or phage, may help protect host cells from invasive microbes, he and his colleagues reported June 25 in the Proceedings of the National Academy of Sciences (SN Online: 5/20/13). Within the mucus barrier that lines airways and intestines and coats the mouth and other orifices, the host and phage conspire to control the movement of bacteria. Anchored to sugars produced by host cells, phage infect and blow up invading bacteria that try to cross the mucus barrier.

As scientists take a census of the virome, they’ve begun to reveal these kinds of unexpected partnerships, but the work lags far behind that of the rest of the microbiome.

No comments: