Why Anthrax Spores Are So Hard to Kill

"It needs special care to eradicate it," a doctor says.

"Because it’s a spore-forming organism, it needs special care to eradicate it," Tosh said.

John Clements, Tulane University School of Medicine professor and chair of the school's Department of Microbiology and Immunology, said spores can stay in the environment for 100 years or more. Clements likens it to a plant seed.

"They’re stable until you put them in fertile ground and give them some nutrients," he said. "In this case the fertile ground is mammalian tissues. If that fertile ground is a cut in your skin you get cutaneous anthrax. If that fertile ground is your lung, you get inhalational anthrax."

"It’s kind of like being in the middle of an onion," Morse said, including a hirsute nap, exosporium, spore coat and cortex that surround the "core" that will germinate, or "grow up," under suitable conditions.

But Morse said there are a number of ways to kill anthrax spores, including irradiation and chlorine compounds, when applied "vigorously and for a long enough time."

"They’re among the hardiest of conventional organisms," Morse said.