Gastrointestinal (GI) anthrax is the most prevalent form of naturally acquired Bacillus anthracis infection, which is associated with exposure to vegetative bacteria in infected meat (carnivores) or to fermented rumen contents (herbivores). We assessed whether key host and pathogen factors modulate infectivity and progression of infection using a mouse model of GI infection. Gastric acid neutralization increases infectivity, but 30%-40% of mice succumb to infection without neutralization. Mice either fed or fasted before exposure showed similar infectivity rates. Finally, the pathogen's anthrax lethal factor is required to establish lethal infection, whereas its edema factor modulates progression and dissemination of infection.
Keywords: edema factor; gastric acid; gastrointestinal anthrax; lethal factor; vegetative Bacillus anthracis.
Published by Oxford University Press for the Infectious Diseases Society of America 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.