Anthrax-Eating Virus Discovered on Zebra Carcasses in Africa

While examining the carcasses of zebras that were killed by anthrax in Africa, researchers found a large type of virus that infects the bacterium that causes anthrax. In the future the virus, known as a bacteriophage, could be used as an alternative to antibiotics for anthrax treatment or for decontamination efforts, the researchers report in the journal PLOS One.

The bacteriophage was isolated from samples collected on zebra carcasses in Namibia's Etosha National Park. The zebras died of anthrax (Bacillus anthracis) poisoning, likely by grazing in an area where anthrax spores were present. Anthrax spores can survive for long periods in soil.

The anthrax bacterium can invade and kill a host species. But bacteriophages like the ones the researchers found on the zebras are viruses that invade and kill bacterial hosts. The bacteriophage found on the zebras was a voracious consumer of the anthrax bacteria. Bacteriophage literally means "bacteria eater."

The bacteriophage, which the researchers named Bacillus phage Tsamsa, is unusually large. It has a giant head, a large tail and a long genome. It ranks as one of the largest known bacteriophages, the researchers report.

The newly discovered bacteriophage also infects bacterial strains closely related to anthrax, such as Bacillus cereus, which can cause food poisoning.

Bacteriophage were once a strong area of interest for scientists when they were discovered in the early 20th century, but interest in them faded upon the discovery of penicillin.

"With growing concerns about antibiotic resistance and superbugs, people are coming back to look at phages," said Holly Ganz, a research scientist at the University of California-Davis Genome Center and first author of the paper.

Ganz said that bacteriophages have the advantage of being specific, which means they could be used to target only "bad" bacteria while leaving beneficial bacteria unharmed.

She said she hoped future research will offer novel uses for the new bacteriophage.

"You might use it to detect the anthrax bacillus or B. cereus; use it as an alternative to antibiotics or as part of a decontaminant," she said.