Hoping to hasten the doomsday their leader foretold, scientistswho were members of Japan's Aum Shinrikyo cult brewed batches ofanthrax in the early 1990s and released it from an office buildingand out the back of trucks upwind of the Imperial Palace.
But the wet mixture kept clogging the sprayers the Aum Shinrikyoscientists had rigged up, and, unbeknown to them, the strains ofanthrax they had ordered from a commercial firm posed no danger toanyone. Frustrated by their failure at biowarfare, they turned to aless arduous method of mass killing -- chemical attack -- and in 1995killed 12 Tokyo subway riders by releasing sarin gas in the tunnels.
The cult's experiences demonstrate just a few of the myriadtechnical obstacles that terrorists who might try to manufacturebiological weapons could face, problems that would confound evenskilled scientists who tried to help them, biological warfare expertssay.
Locating virulent anthrax specimens with which to brew an attack-size batch would be difficult given the medical community's cautionabout suspicious buyers. Smallpox could be next to impossible toobtain because it is thought to exist in only two secure sites, inRussia and in the United States.
Creating aerosolized microbes also requires expertise in manyarcane scientific disciplines, such as culturing and propagatinggerms that retain their virulence and "weaponizing" them so theyfloat like a gas and enter the lungs easily.
But specialists also say it is all but inevitable that al Qaeda oranother terrorist group will gain the expertise to launch small-scale biological attacks and eventually inflict mass casualties.Information on the mechanics of creating bioweapons is easilyaccessible on the Internet and in technical manuals, and theequipment to do the job is readily found. Many brew pubs, forexample, have fermenters that can cook up deadly germs.
Advances in bioscience, and the rapid dissemination of thisknowledge worldwide, are making it easier for even undergraduates tocreate dangerous pathogens. Creating microbe weapons is morechallenging than producing the simplest implements of terrorism --conventional explosives or chemical weapons -- but much lessdifficult than the most technically daunting -- nuclear weapons --experts say.
Richard Danzig, a former Navy secretary and now a biowarfareconsultant to the Pentagon, said that while there are 1,000 to 10,000"weaponeers" worldwide with experience working on biological arms,there are more than 1 million and perhaps many millions of "broadlyskilled" scientists who, while lacking training in that narrow field,could construct bioweapons.
"It seems likely that, over a period between a few months and afew years, broadly skilled individuals equipped with modestlaboratory equipment can develop biological weapons," Danzig said."Only a thin wall of terrorist ignorance and inexperience nowprotects us."
Some agents are simpler than others to weaponize. Toxins such asbotulinum, which is not contagious and unlikely to cause masscasualties, are the easiest to turn into weapons, particularly for afood-borne or water-borne attack. Bacterial agents such as anthrax,which also is not contagious, are more difficult to manufacture.Viruses such as smallpox, which is contagious and could killmillions, are tougher still.
The most challenging are some of the new 21st-century bioweaponsthat scientists contemplate being created in the future -- butexperts believe even these compounds are fast becoming easier toproduce.
In 2002, a panel of biowarfare experts concluded in a report co-published by the National Defense University (NDU) that whileterrorists could mount some small-scale bioattacks, larger assaultswould require them to overcome many technical hurdles. Some keybiotechnologies would be achievable only three to four years fromthen, the panel found.
"When we sent out the report for review to [hands-on] benchscientists, we got the response, 'What do you mean we can't do this?We're doing it now,' " said Raymond Zilinskas, a co-author of thereport who heads biowarfare studies at the Center forNonproliferation Studies, a California think tank. "It shows how fastthe field is moving."
Those skeptical of the prospect of large-scale bioattacks cite thetiny number of biological strikes in recent decades. Members of theRajneeshee cult sickened 750 people in 1984 when they contaminatedsalad bars in 10 Oregon restaurants with salmonella. Among the fewothers were the 2001 anthrax attacks through the U.S. mail thatkilled five people.
One reason for the small number of attacks is that nearly everyaspect of a bioterrorist's job is difficult. The best chance ofacquiring the anthrax bacterium, Bacillus anthracis, is either fromcommercial culture collections in countries with lax securitycontrols, or by digging in soil where livestock recently died of thedisease -- a tactic Aum Shinrikyo tried unsuccessfully in theAustralian Outback.
Once virulent stocks of anthrax have been cultured, it is notrivial task to propagate pathogens with the required attributes foran aerosolized weapon: the hardiness to survive in an enclosedcontainer and upon release into the atmosphere, the ability to lodgein the lungs, and the toxicity to kill. The particles' size iscrucial: If they are too big, they fall to the ground, and if theyare too small, they are exhaled from the body. If they are improperlymade, static electricity can cause them to clump.
Making a bug that defeats antibiotics, a desired goal for anybioweaponeer, is relatively simple but can require laborious trialand error, because conferring antibiotic resistance often reduces abioweapon's killing power. Field-testing germ weapons is necessaryeven for experienced weapons makers, and that is likely to requireopen spaces where animals or even people can be experimentallyinfected.
Each bioagent demands specific weather conditions and requiresunforgiving specifications for the spraying device employed. "Dry"anthrax is harder to make -- it requires special equipment, andscientists must perform the dangerous job of milling particles to theright size. "Wet" anthrax is easier to produce but not as easilydispersed.
Experts agree that anthrax is the potential mass-casualty agentmost accessible to terrorists. The anthrax letter sent in 2001 tothen-Senate Minority Leader Thomas A. Daschle (D-S.D.) contained onegram of anthrax, or 1 trillion spores.
In a 2003 report for the Pentagon, Danzig estimated that ifterrorists released a much larger amount of skillfully made anthraxparticles under optimal weather conditions in a large city, 200,000people in an area 40 miles downwind of the release would be infected,and, if untreated, 180,000 of them would die. Smaller numbers woulddie as far as 120 miles away.
Government officials would probably realize that an attack hadoccurred a day or two later, when victims began to show up inemergency rooms with flulike symptoms. Guessing the geographicalspread of the attack, officials would then order emergencydistribution of ciprofloxacin or other antibiotics, which wouldprobably save many lives -- although experts agree the public healthresponse would be likely to be chaotic and possibly ineffective.
For most experts, the most frightening anthrax scenario is anantibiotic-resistant bug, which many say is not far-fetched. It is"one of the big things we're worried about," Philip K. Russell, a topbioterrorism adviser in the Department of Health and Human Services,said in an August interview in the trade journal Biosecurity. "It'smy view that we have about three or four years to come up with asolution to multidrug-resistant anthrax. . . . We haven't takenanthrax off the table as a threat that can create a very bigdisaster."
Government officials also said they accept a Danzig theory thatterrorists probably would launch bioattacks against various citiessimultaneously or sequentially, using a tactic he calls "reload."Danzig said it would be designed to overwhelm government responsesand undermine public confidence in officials.
"Our national power to manage the consequences of repeatedbiological attacks could be exhausted while the terrorist ability toreload remains intact," he wrote in the Pentagon report.
The 2002 NDU study -- led by Zilinskas and Seth Carus, abiowarfare expert at the university -- concluded that at that time,large-scale bioweapons were less likely to be fashioned by terroriststhan by nations such as Iran, or by disgruntled bioscientists. Thereport also detailed the skill levels necessary to accomplish variousbiowarfare-related tasks. A "junior scientist," for example, coulduse genetic engineering to weaponize both bacterial and viralpathogens.
Experts say that since then, the spread of knowledge and theincreasing availability of sophisticated equipment have placed moreand more complex tasks within the ability of less-skilled people.Some experts expressed concern about the easy availability ofinexpensive biological "kits" from commercial catalogues thatstreamline cloning and other once-daunting tasks.
The Zilinskas-Carus report said it is "chancy" to estimate whichweapons terrorists could make after 2005 because of scientists'increasing ability to synthesize and manipulate biological materialsuch as DNA.
"Novel DNA sequences are being designed and inserted into livingcells by undergraduates," said Roger Brent, a biowarfare expert whois president of the Molecular Sciences Institute, a leading researchgroup in Berkeley, Calif.
Some scientists doubt terrorists will master genetically alteredsuperbugs. But Brent and other experts raise the specter ofterrorists' hiring scientists who can insert a toxin into, say, abioengineered SARS virus, which would then be as contagious as severeacute respiratory syndrome and as fatal as the toxin inside it.
Last year, Brent told a study panel convened by the CIA thatcurrent biological capability resembles the capacity of computers in1965, or English cotton mills in the 1800s -- technologies on thecusp of explosive growth. He said the day is coming when not onlyterrorists but "garage hackers" will be able to assemble bioweapons.
The CIA panel's late 2003 report, "The Darker Bioweapons Future,"said that "the same science that may cure some of our worst diseasescould be used to create the world's most frightening weapons. Theknow-how to develop some of these weapons already exists."
Even banned viruses such as smallpox might be employed one day byterrorists who sidestep the difficulty of obtaining them bysynthesizing agents that resemble them, Brent told the panel. "Oncesynthesized," he said, they "can be grown in indefinite quantities."
"The Rubicon has already been crossed and the process of creatingnovel genetically engineered orthopoxviruses [diseases includingsmallpox] is irrevocable," Ken Alibek, a former Soviet bioscientistwho defected to the United States, wrote recently in a scholarlyjournal. "It is just a matter of time before this knowledge willresult in the creation of super-killer poxviruses." He added: "If athreat, no matter how small, of a smallpox attack exists, it must beaddressed" by developing smallpox detection systems and medicines.
"The alternative," Alibek wrote, "is to remain as helpless as themillions of people who died of smallpox over previous centuries."
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