Researchers determine anthrax can grow and reproduce in soil

University of Virginia School of Medicine researchers reported this week that anthrax is able to grow and reproduce in soil, increasing the bacteria's chances of infecting cattle and other mammals.

It was previously thought that anthrax spores remained dormant in soil until eaten by animals. Scientists thought that rainy weather created rainwater runoff to concentrate spores in low-lying areas, Health Canal reports.

"If you put Bacillus anthracis into soil with basically any other common soil bacteria, it will be out-competed," Ian J. Glomski, a researcher on the project, said, according to Health Canal. "The other bacteria will eat up all the nutrients before Bacillus anthracis can do significant growth. So for all intents and purposes, it has been thought that the spores sit in the ground and do nothing until they go into an animal and cause disease."

Glomski and his team found that the anthrax spores can attack Acanthamoeba castellanii, a common water and soil amoeba. The deadly bacteria then turn the single-cell organisms into incubators of anthrax.

"These amoeba normally eat bacteria and kill them, but Bacillus anthracis has figured out some way to manipulate that amoeba so that it can actually grow inside the amoeba and increase its numbers," Glomski said, according to Health Canal. "The interactions with the amoeba, essentially, are making certain that the anthrax has the tools to kill the amoeba, and those same tools are potentially being used to infect animals and humans."

In the laboratory, the researchers recreated warm and wet conditions where anthrax spores are most common. The presence of the spores increased 50-fold within 72 hours when the amoebas were added to the environment.

Glomski said that the discovery could give researchers new targets for preventing the spread of anthrax.

"If we can figure out any way to disrupt the cycle, that would effectively eliminate the problem," Glomski said, according to Health Canal. "It could be doing something to the bacteria, doing something to the amoeba, doing something to prevent their interaction. If we really understand those interactions, we'll have more and more points of intervention to think about."