Narrator:       This is Science Today. Botulism, a disease that causes muscle paralysis, is classified as a Category A bio-terrorist threat by the Department of Homeland Security — alongside anthrax and smallpox. Now a team of scientists at the University of California, San Francisco, has developed a battery of antitoxins that can combat the worst strains of the neurotoxin.

Marks:           It is the most poisonous substance known to man. An ounce of botulinum toxin could kill hundreds of thousands of people.

Narrator:       Researcher James Marks discovered the antibodies that are now being engineered into the first recombinant human therapy for botulism. The challenge, he explains, was developing a variety of antidotes that would target the many different strains of the toxin.

Marks:           From a drug development point of view, we're not developing a drug for one target. We're actually developing a drug that needs to bind and neutralize 32 different toxins.

Narrator:       The first antidote is now in clinical trials, while two more are nearing completion. For Science Today, I'm Larissa Branin.