Botulism has long been considered one of the most dangerous types of bacterial poison known to man. But scientists have discovered a whole new strain that’s so lethal they refuse to publish the toxin’s DNA sequence, to keep it out of the hands of terrorists.
For the past 40 years, scientists have been aware of seven strains of the deadly bacteria. Last week, researchers in Sacramento, Calif., found an eighth strain, which they have labeled BoNT/H. The first seven strains are lettered A through G. Unlike the first seven, for which anti-toxins exist, the “H” strain has no known antidote.
Until one is formulated, the researchers say it is too dangerous to let details of the newly discovered bacteria out to the public. Botulism has long been regarded as a biological warfare weapon. In the March 20, 1995, terror attacks on Tokyo’s subway system, the Aum Shinrikyo doomsday cult attempted to release botulism as well as the sarin gas that killed 13 people.
For an adult, a deadly dose of botulism when inhaled is a mere 13 one-billionths of a gram.
Infants are particularly susceptible to botulism. The new “H” strain was discovered in the feces of an infant who suffered from symptoms of botulism poisoning.
Researchers are already at work trying to find an antidote for the new strain. None of the antibodies they’re tried so far, in experiments on mice, have stopped the lethal germs.
Typically, gene sequences for any new bacteria are entered into the public database called GenBank. But in an extraordinary decision, the “H” type botulism has not been released due to security concerns.
“Until anti-BoNT/H antitoxin can be created, shown to be effective, and deployed, both the strain itself and the sequence of this toxin (with which recombinant protein can be easily made) pose serious risks to public health because of the unusually severe, widespread harm that could result from misuse of either,” wrote biologist David Relman, in a commentary that accompanied publication of the findings.
SOURCES: Smithsonian Magazine, New Scientist