Virus Wars: Using "Good" Viral Agents to Combat Killer Viruses

We fear viruses, and for good reason: they spread disease and infection. But new research suggests that we can enlist the help of certain viruses in fighting off the more lethal ones of their kind, in what the researchers are calling a "virus wars" approach.

A team of microbiologists at the University of Texas came up with the system, which they delineated in a PeerJ journal article under the title, "Virus wars: using one virus to block the spread of another." In the paper, they said that their methodology employed "a single bacterial host (E. coli), a lethal bacteriophage whose numbers we wish to limit, and a non-lethal phage as the therapeutic agent that protects host cells from the lethal bacteriophage."

A bacteriophage, or phage, is a virus that infects and propagates within a bacterium, often killing it. A few scientists have sought to use phages as antibacterial agents, applying so-called "phage therapy" as an alternative to giving patients antibiotics. Notably, there was the microbiologist Felix d'Herelle, a co-discoverer of bacteriophages, who worked to popularize phage therapy and develop commercial drugs out of it.

Somehow, phage therapy never caught on. "It's been nearly a century since the Canadian physician Felix d'Herelle discovered viruses that infect bacteria. And yet, despite great promise, phage therapy has yet to become a mainstay of medicine," lamented science writer Carl Zimmer on The Chicago Blog.

The "virus wars" method carries on the d'Herelle legacy. The university researchers set up two separate colonies of E. coli bacteria. One colony was left alone, while the other was deliberately infected with a "therapeutic virus"-the filamentous phage f1.

The team then introduced a lethal virus, the phage Qβ, to both colonies. As noted by RealClearScience, "In colonies infected with the therapeutic virus, host populations remained fairly stable, while host populations without the therapeutic virus saw their numbers dwindle by two orders of magnitude."

The study points the way toward future applications, such as injecting patients with therapeutic viruses that are designed to pre-emptively keep lethal viral infections at bay.