Lessons From Failed 1993 Biological Attack

Oct. 5, 2001 -- There's been a lot more protection around Paul Keim's lab recently.

"Without giving you specific details, the security has jumped 10 times in the last three weeks," said Keim. "Amazing times in a small town."

What's being protected at the University of Northern Arizona lab in Flagstaff is a genetic database of anthrax strains taken from outbreaks in every region of the world.

This year, Keim used the database to identify what went wrong when the Aum Shinrikyo cult attempted to kill thousands of people by spraying steady mists of anthrax from a rooftop and a vented van in Japan in 1993.

For Keim and other researchers specializing in lethal biological agents, the failed 1993 attempt offers lessons in both hope and caution. The hope comes from the fact that, despite trying for years to launch a biological attack, Aum Shinrikyo never managed to kill or apparently even injure one person using biological agents.

What's discouraging is that officials never caught on to the cult's efforts until two years later when it launched a deadly chemical attack in a Tokyo subway that killed 12 people and injured thousands. Also troubling is that the anthrax strain the cult used, though harmless, is still perfectly viable, even after eight years of storage.

"You can make it and put it on a shelf for years," said Martin Hugh-Jones of the College of Veterinary Medicine at Louisiana State University. "It's a killer and it's very efficient at it."

Cult Botched Many Attempts

Since the 1993 sprayings had no apparent ill effects, Japanese officials only learned about the attack through testimony two years later from former cult members. They said a cult member who was a former graduate student in biology had first acquired a strain of the toxin-producing botulism, and members then sprayed large quantities of it from trucks. The strain was evidently weak or inactive since no deaths or illnesses were reported.

Next, the former biology student acquired a small sample of anthrax through a member who had medical credentials. They cultivated the bacteria in large vats stored in an eight-story concrete building in eastern Tokyo.

Then, they said, the cult members used a spraying device to spread a cloud of the slurry anthrax liquid from the building's rooftop. When that had no results, they tried dispersing the agent through vents in trucks as they drove through the city. Again, no one got ill.

Japanese officials long suspected the anthrax strain the cult used was flawed, and Keim's lab confirmed the strain they used was an anthrax vaccination developed for cattle.

"While they may have been trying to kill people, the most they could have done is actually immunize people from the disease," said Keim. "But there's no sign that that happened either."

Common Among Animals

Anthrax is a fairly common disease among cattle and sheep, and so many veterinarians have access to vaccine strains of the bacterium.

These strains lack mechanisms, present in virulent strains, that protect the bug from its hosts' defenses. When an anthrax agent lacks these defenses, a cow or sheep — or person — can fight off the disease and, in the process, become immune from future infections.

As Hugh-Jones says, "The vaccine goes naked into the fight and gets killed."

It's uncertain why the cult members used such a strain. Keim supposes someone had a change of heart and substituted a dangerous strain with the harmless one. Or perhaps the members never knew the strain wouldn't kill people. Either way, the the anthrax sample was clearly flawed.

Anthrax: Hard to Get, Harder to Weaponize

The cult members' failed attempt also points out how difficult it is to transform a bacterium like anthrax into a deadly weapon. It appears the members tried to disperse the agent in its liquid form. As a liquid, the agent is much less likely to lodge in a victim's lungs, where the disease takes root.

Even if the cult members managed to produce anthrax in a powdered form, it now seems unlikely they had crafted it to the required grain size for infection since there were no medical reports citing any symptoms — such as mild respiratory irritations — that one might experience from an anthrax vaccine.

"It's one thing to have anthrax, it's another to infect people," said Keim. "I can access any anthrax strain, but I can't make it into a powder. That takes sophisticated technology. I think we can be hopeful that's a big enough hurdle to deter most, if not all terrorists."

But why didn't authorities catch on to their plans? In fact, Japanese police had visited the site after receiving complaints of an odor so foul it made some residents near the Aum building nauseous. The cult members told authorities they were just boiling beans. Since anthrax is odorless, Keim believes the stink likely came from ammonia and sulfur compounds used to culture the bacteria.

"People don't like to walk into my lab when we're growing bacteria," said Keim.

Kaim said authorities suspected the cult members might be disposing of murdered victims' bodies so they took samples of the ooze-like substance from the building to test for human proteins. The researchers at the time did not look for biological agents in the sample. When they found no human proteins in the sample, they abandoned their effort to search the building.

Changed Times

Following last month's terrorist attacks, inspectors are likely to be much more aggressive and alert. Keim points out there would be many signs of anyone trying to produce a biological weapon. The clues could be strange odors coming from a building or even, Keim says, someone buying a large loads of beef consume (anthrax thrive in beef stew, he says).

Detection has also gotten better. At Lawrence Livermoore Laboratory, for example, researcher Gary Andersen has developed a device that can identify the unique strands of a biological agent's DNA. The device can detect a harmful agent within hours, rather than the 10 days it has taken health officials to confirm the presence of a deadly agent using older methods.

Keim believes these devices will soon be available in up to 50 locations throughout the country.

"The technology had already begun before Sept. 11," said Keim. "But it will move faster now. More money will come in and people in the public health field are working harder than ever."