Horse owners in most areas of the country would grow wide-eyed if they heard anthrax had been discovered in horses or other livestock in their region. On the other hand, individuals in the Great Plains (North Dakota to Texas) and Intermountain Basin states (Nevada and Utah) regularly vaccinate their animals against anthrax and are used to hearing about cases every few years, if not annually. They also know cases should be reported. Because of these tendencies, government health authorities say it’s possible to tell if an outbreak is a usual occurrence or if it’s a concern for national security, to which they could respond quickly.

Background on Anthrax

The anthrax agent is a resilient spore-forming bacterium called Bacillus anthracis, which lives in the ground. Livestock become infected when they ingest spores of  B. anthracis when they forage on vegetation growing in infected soil or eat contaminated feed. Horses seem to be more resistant to anthrax than other livestock species, such as sheep or cattle.

B. anthracis was  researched by German scientists as an agent for biological warfare purposes during World War I for use against livestock and draft animals used by the Allied armies. Sean Shadomy, DVM, MPH, is a Medical Epidemiologist in the Centers for Disease Control (CDC), National Center for Infectious Disease, Meningitis and Special Pathogens Branch, in Atlanta, Ga. He says, “Germany was the first place where anthrax was weaponized in the modern sense. It wasn’t until World War II that it was researched for (use against) humans. Throughout the course of the Cold War, a number of countries looked at anthrax.”

In his job, Shadomy identifies and detects human disease cases such as anthrax and traces them to their possible source. “Anthrax is very hardy–if you look for it, you will find it,” he says. “There have been bones that have been found in some of the national parks in Africa that have had anthrax spores … that are well over a century old. It’s the same case in building insulation materials using horsehair and things of that nature