Residents of Los Angeles must recognise that the threat of bioterrorism is not a curiosity, but a grim reality as we enter the next century,' says Olson. Most importantly, argue Olson, Zilinskas and others, public health authorities and emergency services must start planning now to cope with the aftermath of a variety of biological attacks.

Biological weapons have been with us for half a century or more, but military commanders consider them too unpredictable and slow-acting, preferring the touch-of-a-button reliability of explosives. What is more, the international condemnation that the use of biological weapons would provoke gives any rational military strategist pause. Biological weapons are also an unlikely choice for most politically inspired terrorist organisations. 'Traditionally, political terror groups are trying to get a seat at the table and to establish the legitimacy of their cause,' says Brad Roberts, a biological weapons expert at the Institute for Defense Analyses, a think-tank in Alexandria, Virginia. That goal would not be met by resorting to bioterrorism.

Nonetheless, terrorist experts fear that the probability of a surprise biological attack on an unprotected city is higher today than ever before. Many point to a new brand of terrorism-epitomised by Aum Shinrikyo-that lacks the restraints imposed by a political agenda. 'There are new actors appearing, individuals and small organisations that don't seem to care about establishing legitimacy, but just want to strike a blow in anger and kill as many people as possible,' says Roberts. 'For them, the calculation of the right level of violence seems to have no upper bound.'

In addition, the number of trained biologists is soaring. Life science PhDs awarded in the US increased by 30 per cent between 1975 and 1991 to more than 5700 a year. By 1994 England alone had 5700 biology graduate students. American industry now employs around 60 000 life scientists. There are over 1300 biotechnology companies in the US and about 580 in Europe; 25 years ago there were none. Moreover, many less developed countries, including Iraq, have their own biotechnology industries.

The threat does not come from the fictional mad scientist engineering a deadly new germ, says Zilinskas, although the technology to create a Satan bug may soon be within our grasp (see 'What if . . .'). Instead, the widespread use of the basic tools of industrial biology has put the power to create 'traditional' biological weapons in the hands of tens of thousands of people. 'Advanced biological technologies have spread all over the world,' says Zilinskas. 'There are many more people who are technically trained, and the methods for culturing large quantities of bacteria are well worked out and commonly employed.'

Olson agrees: 'A person who is smart, determined, trained in basic microbiological techniques, and willing to take a few short-cuts on safety and go at a few technical problems in mildly unconventional ways, could conceivably do some horrible things.'

Horrible indeed. Bioterrorism is distinguished not only by its mode of killing, but also by the potential scale of destruction-thousands of times as many people as could be killed by a typical car bomb. That awesome potential has caught the attention of the US government. A 1993 report on weapons of mass destruction by the US Office of Technology Assessment (OTA) lists the diseases that could be employed as biological weapons. They include plague; tularemia, a plague-like disease; and botulism, caused by a toxin from the common food-poisoning bacterium Clostridium botulinum. But the most chilling reading in the report is the story of anthrax, the original biological warfare agent.

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Anthrax, a disease of cattle and sheep caused by Bacillus anthracis, can also kill humans. The external form of the disease, which sometimes strikes people who handle infected fleeces, causes unpleasant sores. The pneumonic form is far more serious, killing more than 90 per cent of its victims if left untreated. The key to triggering the second form of the disease is to create and disperse spore-containing particles of exactly the right size-between 1 and 5 micrometres-to ensure that they are retained in the lungs. As few as 8000 spores per person reliably causes a lethal infection. The spores cross the epithelial lining of the lungs and travel to the lymph nodes, where they germinate, multiply, and then spread to the other tissues, releasing toxins as they go. The first symptoms include vomiting, fever, a choking cough and laboured breathing. Antibiotics can cure patients in the earlier stages of the disease. Without antibiotics, death from haemorrhage, respiratory failure or toxic shock follows within a few days.

The OTA report emphasised that, for the most part, transforming B. anthracis into a weapon is a low-tech procedure. It also noted that on a clear, calm night, a light plane flying over Washington DC (similar to the one that crashed into the White House in 1994), carrying 100 kilograms of anthrax spores and equipped with a crop sprayer, could deliver a fatal dose to up to three million people.

Zilinskas emphasises that making an anthrax weapon capable of murder on this scale is not a trivial undertaking. But while it may be much more difficult than building a fertiliser bomb, the problems are far from insurmountable. The tricky part, he says, is not culturing the agent, but processing the crude slurry into a form suitable for dispersal. 'You have to dry it somehow, adjust the particle size, load it into a canister, and spray it. If you wanted to be sure your preparation would work, you would also need to test your isolate for virulence, measure the particle size and perhaps field test your sprayer with a non-pathogenic bacterium. All the while you have to protect yourself and avoid detection.'

A project of this complexity would require months of systematic effort, the practical engineering skills of a clever back-yard inventor, and luck. These barriers, however, are not impossibly high. Basic microbiology skills-techniques an undergraduate studying the subject would be taught-should be sufficient to isolate B. anthracis from cattle pasture in areas where the disease is endemic, such as small areas of the US, and larger tracts of land in Russia and South Africa. Using this as the starter culture, a terrorist with a 100-litre culture vessel-about the size of a home fish tank-could in a few days brew up several kilograms of crude slurry containing billions of spores. Drying the slurry would be tricky, though not impossible. Freeze-drying-a procedure in which material is frozen and put under a vacuum to remove water, and which is used on a small scale throughout the biotech industry-could be one option. Grinding the slurry powder into particles of the desired diameter would provide the greatest challenge, mainly because of the risk of contamination. Indeed, the most likely glitch all round is that the terrorists become the first victims, or that they infect their neighbours and give the game away.

Moreover, Zilinskas says a few essential details are not commonly known. 'The Iraqis, as far as we know, never mastered the art of weaponising their bacterial agents, which included anthrax,' he says. 'Most of what the UN investigators found were crude preparations mounted on conventional bombs and missiles, which might not have dispersed very well.' But he notes that less ambitious attacks also pose a threat. For example, a crude slurry of anthrax spores left in the tunnels of an underground railway system, where wind created by passing trains would dry them and blow them around, could claim thousands of lives.

The Aum Shinrikyo attack on the Tokyo underground fell into this less ambitious category-and even that was bungled. Olson, who interviewed cult members in Japan both before and after the Tokyo incident, says that the attack was hastily planned, the batch of sarin nerve gas the cult members manufactured was impure, and the dispersal device was nothing more than a bag punctured with an umbrella tip. Had the sarin been pure, and the dispersal mechanism slightly more sophisticated, tens of thousands could have died.

But John Sopko and his colleagues on the staff of the US Senate Permanent Committee on Investigations, who were asked to look into the attack by Senator Sam Nunn of Georgia, found that despite the cult's ineptitude there was plenty of reason to take notice. In a report presented last November at one of a series of Senate hearings on terrorism, they wrote that the cult, which had more than 40 000 members in Japan and Russia and one billion dollars in assets, had recruited hundreds of scientists to assist with its 'avowed purpose of plunging the United States and Japan into a war of 'Armageddon' from which the cult would arise as the supreme power in Japan.'

Sopko and his colleagues-not the kind of people given to sensationalism-also noted that 'although the findings may initially sound far-fetched and nearly science fictional, the actions of the Aum . . . create a terrifying picture of a deadly mix of the religious zealotry of groups such as the Branch Davidians, the anti-government agenda of the US militia movements and the technical know-how of a Doctor Strangelove.' A manual on sarin production included the song Sarin, The Brave with the catchy lines 'Prepare Sarin! Prepare Sarin! Immediately poisonous gas weapons will fill the place. Spray! Spray! Sarin the Brave, Sarin.'

The cult also had a large biological weapons programme, the precise extent of which remains unexplored to this day. 'There is an Aum lab-now sealed-that was devoted to biological agents, which has not yet been fully investigated,' says Olson. 'As early as 1990 they were trying to aerosolise botulinus toxin. We think they had anthrax as well. In 1991, (cult leader Shoko) Asahara led an expedition to Zaire to obtain samples of the Ebola virus. We have to assume they had progressed since then, but how far they got we don't know.'

The Japanese cult is now out of action. 'My concern is (that) new groups will look at Aum Shinrikyo's activities and ask: 'How could I do this a little better?' ' says Roberts. Compared with Sarin gas, he says, 'biological agents might look a lot easier to work with-in terms of access to material, and the level of expertise needed-and more effective'. Only time will tell whether the Aum Shinrikyo attack will inspire or deter. But the Japanese tragedy has sparked concern that greater efforts are needed to prevent and prepare for a bioterrorist attack. On the intelligence front, the Aum experience is not encouraging. The Japanese authorities were aware of some of the cult's activities, and were poised to move against them. But though the US was known to be one of the cult's avowed targets, John O'Neill, chief of the Counterterrorism and Middle East Section of the FBI, admitted to the Senate that the cult's activities 'weren't on our radar screen'.

Apart from acting on intelligence, another defence would be to restrict access to the tools of bioterrorism, including starter cultures. In March 1995, Larry Harris, a microbiologist and a member of the Aryan Nations white supremacist group, used a forged letterhead and his professional credentials to order samples of Yersinia pestis, the organism that causes bubonic plague, from the American Type Culture Collection, a clearing house for microbiological samples in Rockville, Maryland. The ATCC dutifully mailed the samples, but in the nick of time staff became suspicious that Harris did not have the expertise to handle plague and the vials were recovered unopened. Harris is being prosecuted for mail fraud-owning plague, it transpires, is not illegal in the US. In Britain any company that wants to keep lethal pathogens must prove to the government's Health and Safety Executive that it has adequate containment facilities. But, according to spokesman Mark Wheeler, the HSE has no jurisdiction over private citizens. Lindsey French of the Department of Health confirms that people may keep lethal pathogens at home. But she says that threats to do harm with those pathogens, transporting or storing them improperly, or obtaining them by fraud or theft, are illegal. Not that would-be terrorists need obtain their pathogens through official channels. If you know where to look, many can be isolated from the wild.

But perhaps the most neglected area of planning is the medical response to an attack. 'The scenario changes with the agent used,'' says Philip Russell, former commander of the US Army Medical Research and Development Command in Fort Detrick, Maryland. He is now president of the Sabin Foundation, an organisation based in New Canaan, Connecticut, which promotes vaccine use against natural diseases. 'Plague is different from smallpox, which is different from anthrax. We need a group of folks to go through different scenarios and think about what could be done other than counting the bodies.' For example, he says, plans are needed to ensure that large amounts of antibiotics, and properly trained and equipped people, can be rushed to the scene.

In the US, these responsibilities fall to the Federal Emergency Management Agency and the Office of Emergency Preparedness of the Department of Health and Human Services, both in Washington DC. At the moment, although these agencies have adequate plans to cope with floods, earthquakes, and the occasional car bomb, OEP head Frank Young told a Senate hearing on 1 November 1995, 'there is no coordinated public health infrastructure to deal with the medical consequences of terrorism'. This is not to say there are no plans at all. Last June, President Clinton told government agencies-including the military - to improve their planning for a massive terrorist strike. But at the most recent Senate terrorism hearing, on 27 March, several key witnesses, among them P. Lamont Ewell, president of the International Association of Fire Chiefs, questioned whether the new plans were adequate and whether they had been sufficiently well rehearsed to cope with a real attack. In Britain, the Home Office takes ultimate responsibility for preventing bioterrorism and for preparing to deal with its aftermath. It is characteristically enigmatic. Robert Smith of the Home Office has 'contingency plans drawn up, and they are ready to be used'. But he refused to give any details to New Scientist because 'that would defeat the object of the exercise'.

In the wake of a major bioterrorist attack, undoubtedly the contingency plans would be rapidly and publicly overhauled. Meanwhile, consider this. The mid-morning radio news reports an odd outbreak of a respiratory disease on the fringes of London. It rapidly becomes the top news story, first locally, then nationally, as more cases show up during the afternoon. Hundreds of people turn up at hospitals across the city gasping for breath. Doctors begin to suspect, and quickly confirm, that the bizarre disease is anthrax. An extended evening bulletin gives it saturation coverage. Experts from the Department of Health try to figure out where the spores came from and in which direction they are spreading. It all takes time -- time they don't have. Rumours are rife that supplies of antibiotics have run out. The authorities caution against panic. You know that you and your family have been exposed. . .

Sooner or later there is going to be a biological attack on a major city. Are we prepared to deal with it? Not a chance, says Debora MacKenzie

It begins with a threat. A terrorist group declares that unless its demands are met within 48 hours, it will release anthrax over San Francisco. Two days later, a private plane flies across the Bay, spreading an aerosol cloud that shimmers briefly in the sunlight before disappearing.

Scenario one: thousands are killed in the panic as 2 million people flee the city. Another 1·6 million inhale anthrax spores. Antibiotics are rushed in, but the hospitals are overwhelmed and not everyone receives treatment. Most of the country's limited stock of anthrax vaccine has already been given to soldiers. Emergency crews provide little help as there are only four germ-proof suits in the whole city. More than a million of the Bay Area's 6·5 million residents die.

Scenario two: in the two days before the attack, citizens seal their doors and windows with germ-proof tape. They listen to the radio for instructions, their gas masks, drugs and disinfectants ready. Few panic. When sensors around the city confirm that the cloud contains anthrax spores, hospitals receive the appropriate antibiotics and vaccines. Trained emergency teams with germ-proof suits and tents set up in the places where automated weather analyses show the deadly cloud will drift. With advance preparation and rapid response only 100 000 people die.

A terrorist who plans to drop anthrax over San Francisco tomorrow can count on causing the murder and mayhem described in the first scenario--at least according to the simulation that generated these scenarios last year. The question facing policy makers now is: how do we move toward the second scenario?

That terrorists may someday turn to biological weapons is no longer a matter of debate (see "All fall down", New Scientist, 11 May 1996, p 32). "Terrorism has changed," says Brad Roberts of the US government-backed Institute for Defense Analyses in Virginia. "Traditional terrorists wanted political concessions," he says. "But now, some groups say their main aim is mass casualties. That makes biological weapons appealing."

Terrorists would have little trouble getting their hands on the technology. Hearings in South Africa in June revealed that the apartheid government produced terrorist weapons containing anthrax, Salmonella and cholera. Soviet scientists who have prepared weapons-grade anthrax and smallpox are known to have emigrated, possibly to well-funded terrorist groups like the one run by Osama bin Laden in Afghanistan. Even small groups such as the Aum Shinrikyo sect in Japan have been able to cook up vats of Salmonella or botulin, the toxin that causes botulism.

With bioweapons so readily available, how can governments protect us from a terrorist armed with anthrax, smallpox or plague? In May, scientists, policy makers and security experts gathered in Stockholm to discuss how to limit the devastation of a biological attack on civilians. Until now, most biological defence strategies have been geared to protecting soldiers on the battlefield rather than ordinary people in cities. The situations are quite different, and novel technologies are needed for civilian defence.

Suppose a commuter stumbled across a time bomb filled with anthrax on an underground railway platform. Until this year, no police force in the world had any way to disarm such a device safely. One novel solution that attracted attention at Stockholm was a tent full of antiseptic foam. Researchers at Irvin Aerospace in Fort Erie, Ontario, have developed a dome-shaped tent made of ultratough Mylar that can be filled with a stiff foam--the exact composition of which is a closely guarded secret--that kills germs and also neutralises chemical weapons. Once covered by the foam-filled tent, the bomb can be safely detonated.

But what if germs are already in the air? The protective suits and masks used by most emergency services don't have seals tight enough to exclude microorganisms, making them useless against biological attacks, says Jack Sawicki, a former fireman who now works for Geomet Technologies near Washington DC. And the lack of standards for gas masks sold to civilians in most countries makes it as likely that a mask will suffocate you as save you, he says. The suits developed for the military do work--their tight joints and zippers keep bugs out--but they are too pricey for the average fire department.

Both Geomet and Irvin Aerospace are about to market civilian bio-suits. In the meantime, other companies are designing protective gear that actually kills pathogens. Molecular Geodesics in Cambridge, Massachusetts, for example, is developing a suit made of a tough, sponge-like polymer that traps bacteria and viruses, which are then destroyed by disinfectants incorporated into the fabric.

None of this gear will do any good, however, if the emergency services do not know there has been an attack. And an assault may not be obvious. A terrorist might not use a weapon that goes off with a dramatic bang, or even produces an obvious cloud of germs. The first hint of a biological attack may be a sudden cluster of sick people.

Even that will be missed unless someone is watching. And few are. In the US, financial cutbacks have crippled programmes to track disease outbreaks, natural or deliberate. Some could be either, such as food poisoning caused by Escherichia coli O157 or Salmonella. Medical agencies fear that the extra money requested by President Bill Clinton this spring as part of an anti-terrorist initiative will not be enough to create an adequate surveillance network.

In Europe, disease surveillance is only beginning to be organised on the continent-wide scale needed to track a biological emergency. But in addition to monitoring infected people, Nicholas Staritsyn of the State Research Centre for Applied Microbiology near Moscow says that more effort should be made to find out which bugs live where. For example, a particular variety of anthrax may occur naturally in South Africa, but not in Canada. Having access to such information could help authorities to distinguish between natural outbreaks and deliberate attacks.

Even when infected people start turning up at local hospitals, early diagnosis of their illness might not be easy, says Steve Morse, who heads the US programme on new diagnostic technologies run by the Defense Advanced Research Projects Agency (DARPA). The first symptoms of anthrax, plague and many other potential agents of bioterrorism resemble those of flu: headaches, fevers, aching muscles, coughing. What's more, some of these symptoms might be brought on by panic attacks, which are likely to be widespread among people who have just been told that they are the victims of a biological attack.

One answer discussed in Stockholm would be for hospitals to have the type of high-tech detectors being developed to identify airborne pathogens on the battlefield. With a detector at each bedside, doctors could pick out the volatile molecules released by damaged lung membranes at a very early stage of infection and instantly tell whether a patient was a victim of a biological attack, says Mildred Donlon, head of environmental detection research at DARPA.

Eventually, DARPA would like to develop a detector that weighs no more than 2 kilograms, can identify as few as two particles of 20 different biological agents in a sample of air, costs less than $5000 and does not give false negatives. Such detectors could be deployed around cities to give early warning of airborne disease.

In the meantime, researchers led by Wayne Bryden at Johns Hopkins University in Baltimore are working on revamping the traditional laboratory workhorse, the mass spectrometer, for use in the field or in hospitals. They've reduced this unwieldy piece of equipment to a suitcase-sized machine that can distinguish between, say, Shigella, which causes dysentery, and Salmonella. A shoebox-sized version, says Bryden, could be ready in five years.

Other researchers are experimenting with devices that would not seem out of place in an episode of Star Trek: Voyager. Tiny electronic chips that contain living nerve cells may someday warn of the presence of bacterial toxins, many of which are nerve poisons. Like a canary in a coal mine, the neurons on the chip will chatter until something kills them. "Anything that stops it singing is immediate cause for alarm," says Donlon.

While the "canary on a chip" could detect a broad range of toxins, other devices are designed to identify specific pathogens. One prototype consists of a fibre-optic tube lined with antibodies coupled to light-emitting molecules. In the presence of plague or anthrax bacteria, or the toxins botulin or ricin, the molecules light up.

Devices based on antibodies are far from foolproof. First, you need to have the correct antibodies--not easy when you consider the vast number of pathogens you'd need to include, and their ever-changing repertoire of surface proteins. "And even the right antibodies can identify only what is on the outside of a particle," Donlon points out. Bugs can be encapsulated in gels or biological polymers to foil antibodies, or normally harmless bacteria engineered to carry nasty genes. "I want to know what is on the inside," she says.

To do this, DARPA-funded researchers are developing identification techniques based on RNA analysis. Unlike DNA, which is now used to identify unknown organisms, RNA is plentiful inside cells and need not be amplified before identification begins. And messenger RNA molecules reveal not only what a microorganism is, but what toxins it is making.

Once the biological agent has been identified, how do you combat it? Vaccinating people before they are exposed is one answer. This is the strategy the military is betting on. Last year, the US military launched a programme to develop vaccines against potential biological weapons. It will create jabs for diseases for which none exist, such as Ebola, and improve existing vaccines--including the 30-year-old anthrax vaccine being given to 2·4 million American soldiers.

But vaccines are no cure-all. An attacker need only generate a germ that sports different antigens to those used in a vaccine to render that vaccine ineffective. Plus, as bioterrorists get more sophisticated, they will develop novel, possibly artificial, pathogens against which conventional vaccines will be useless, predicts Morse.

To get around these problems, DARPA is looking at ways of developing vaccines quickly enough for them to be created, mass-produced and distributed after an attack. The first step, which many researchers including those in the fast-paced field of genomics are now working on, involves speeding up DNA sequencing so that an unknown pathogen's genes could be detailed in a day. The resulting sequences could then be the basis for developing an instant DNA vaccine.

Making the vaccine is only half the problem, however. Soldiers can be ordered to take shots, but immunising the rest of the population is another matter. Civilians are unlikely to volunteer for the dozens of vaccinations that would be necessary to protect them against every conceivable biological threat. An attack would make many change their minds, but in such circumstances there might not be enough to go around. Although Clinton has called for the stockpiling of vaccines, the US has only 5 million doses of smallpox vaccine--not enough to contain a hypothetical attack, says Ken Berry, president of the American Academy of Emergency Physicians.

Ken Alibek, the former second-in-command of the Soviet germ warfare programme who revealed earlier this year that the Soviets had weaponised tonnes of smallpox, argues that it is short-sighted to put too much effort into developing vaccines. Instead, says Alibek, who is now at the Batelle Institute in Virginia, researchers should concentrate on ways to treat victims of biological weapons. Today's antibiotics may be useless because germs could be equipped with genes for resistance to all of them. Russian scientists have already created such a strain of anthrax (This Week, 28 February, p 4).

For any treatment to be effective amid the potential chaos of a bioterrorist attack, speed will be of the essence. At the Stockholm meeting, researchers reported their efforts to develop drugs that work against a wide variety of infections and so can be used even before definitive diagnosis. Some are trying to take advantage of recently identified similarities in the way many pathogens produce disease to develop broad-spectrum drugs.

For example, Ebola, anthrax and plague all kill their victims by inducing a widespread inflammatory reaction similar to toxic shock syndrome. A team in Cincinnati is testing an anti-inflammatory drug that could stop all of them. Another gang of bacteria--including plague, Salmonella, Shigella and Pseudomonas aeruginosa (one of the bacteria that can cause pneumonia and meningitis)--relies on very similar proteins to latch onto human cells and inject toxins. Drugs that block this system might save people from all these germs, Åke Forsberg of the Swedish Defence Research Establishment in Umeå told the meeting.

The trouble with all these new anti-bioweapon gizmos, gadgets and medicines is that it's far from certain that they would be available in time to shield the first major city targeted for a bioterrorist attack. At the moment, the US is one of the few countries taking the bioterrorist threat seriously. Sweden, France and Israel have trained emergency teams and stockpiled gas masks. Other countries do not seem concerned. "The threat of bioterrorism has not seized our European friends," says Mike Moodie of the Chemical and Biological Arms Control Institute, a think-tank near Washington DC. "They feel it's too improbable."

Perhaps they should reconsider. Berry, who helped run the doomsday simulations that ravaged San Francisco, says: "Security experts are not asking if a biological attack on a civilian population is going to happen, but when."

Bioterrorism Special Report: Strike at will

Los Angeles has the reputation of being a scary place. So the ominous news that the city has been busy working with the US Army's Chemical and Biological Defense Command seems chillingly appropriate. Simulating an attack on the city by terrorists equipped with biological weapons has already been carried out. Large-scale drills will follow, designed to prepare the city for such possibilities as the release of deadly anthrax spores onto the freeway system.

It is not too surprising that the emergency services are making these plans. The 1995 nerve gas attack on the Tokyo subway that left 11 dead and 5000 injured served as a wake-up call for disaster planners everywhere. But despite the flurry of activity, there remain real worries that no one can really predict just what kind of incident could come next, still less how to cope with it effectively.

The Tokyo attack used nerve gas which acted immediately, triggering a rapid response from the emergency services. Had they released anthrax spores, the effects would have been devastatingly different. No one may have noticed anything strange for a day until the hospitals suddenly began seeing scores of people with an inexplicable illness. Because the spores can quickly spread through underground tunnels and because anthrax can only be treated really effectively in the first 24 hours after exposure to it, the number of casualties could be high.

Fortunately, preparing anthrax spores for a covert attack is quite difficult and any would-be terrorist could easily end up as the first victim. Unfortunately, there are other easier options. Bacteria such as Salmonella which cause food poisoning are far easier to cultivate and simple to slip into either food or water supplies.

Just such an incident has occurred, although it was hushed up for years. In 1984, another cult put Salmonella into the salad bars of 10 restaurants in Oregon. More than 750 people became ill.

Why would anyone carry out such crimes? Both the Tokyo subway attack and the Oklahoma bombing show that the world is changing. Unlike "conventional" extremists who are after political goals, the new breed of terrorist may simply be out to punish society or settle a grudge. Already one ex-employee is suspected of trying to use Salmonella to poison a former boss.

There will be no quick fixes for the threats from bioterrorism. Doctors can be taught to look out for a rash of patients with unusual symptoms. Drugs and vaccines can be stockpiled to meet unexpected needs. Research on faster ways to detect pathogens is already under way.

But the fact remains that many of these deadly agents are not too hard to obtain from hospitals or labs. And once obtained, anyone with some university-level knowledge of microbiology or chemistry would know how to make useful amounts.

While the number of attacks remains relatively low, we can assign them a level of risk which will still put cancer higher up the league table of things to dread. If they increase, we face the bleak choice between poilice states and accepting that these random acts of violence and terror are the price of our freedom.

Random inspections of factories are essential in the global fight against biological weapons. So why won't the US allow them?

A bomb explodes in central London. It does little obvious damage and is put down to a terrorist's mistake. Then hundreds of people start showing up in clinics with bad chest colds, which quickly progress to pneumonia and fever. Patients start dying with lungs choked with fluid and the doctors alert the government. When the lab results come in, the government urges anyone with cold symptoms who was in London the day the bomb exploded to come in for antibiotics. Panic ensues, hospitals overflow and a young doctor leaks the real story to the papers: the disease is anthrax. A week later, the death toll has risen to tens of thousands.

Such a scenario is credible as long as countries possess the means to make biological weapons. It explains why the US and Britain would rather go to war with Iraq than live with the possibility that Saddam Hussein could be hiding anthrax, botulism, aflatoxin and other lethal agents. It is also the reason that 140 countries--including Iraq--have ratified the 1972 Biological and Toxin Weapons Convention (BTWC), which prohibits the manufacture and acquisition of organisms or their toxins for military use.

However, most governments agree that as it stands the convention is ineffective. Unlike the treaties that ban nuclear and chemical weapons, the BTWC provides no legal means to check if countries are complying. Treaty members are now trying to strengthen the convention to include a system of verification. Europe and many developing countries want UN inspectors to make random visits, at short notice, to any factory or lab--in any country--capable of producing lethal organisms.

But the US government, under pressure from its drugs and biotechnology industries, rejects this idea. The companies fear that such visits would expose trade secrets. The issue will come to a head next month when an ad hoc working group of member countries meets in Geneva to continue negotiations on the BTWC.

Supporters of random inspections point out that while the US is willing to go to war to back the UN's right to inspect any sites it chooses in Iraq, it will not grant the UN the same right to inspect itself or the other members of the BTWC. Yet UN inspectors say that such inspections were crucial to discovering biological weapons in Iraq.

Jack Melling of the Salk Institute Biologicals Development Center in Swiftwater, Pennsylvania, and former head of Britain's Centre for Applied Microbiology and Research at Porton Down, Wiltshire, says the current crisis in Iraq "shows how badly we need a verification regime for biological weapons. If we had had one ten years ago, we would almost certainly have known there was a problem in Iraq before things got this bad."

Once Iraq had joined the BTWC after its defeat in 1991, the only legal way to find and destroy the biological weapons that its own generals had claimed it had was for the UN Security Council to set up a special commission, UNSCOM. Through its inspections over the past seven years, UNSCOM has tested many of the ways in which a verification regime would work for the BTWC. These include the compulsory declaration of all research and development involving biological weapons, and of any facilities that could be used to make them. An inspection team then compares this declaration with other evidence, such as government documents, trade records, interviews with scientists and visits to laboratories and factories.

All signatories to the BTWC accept this approach in principle. The sticking point is how extensive the inspections should be. Everyone, including the biotechnology industry, agrees to what are known as "challenge" inspections. If there is "substantial and convincing evidence" of a breach--such as an unexplained outbreak of anthrax--a majority of treaty members can demand an inspection. But, says Barbara Rosenberg, chair of the biological weapons group of the Federation of American Scientists (FAS), "challenge visits will never be frequent enough to be a sufficient deterrent. They require too much evidence and political risk for the country making the charge."

Europe and most developing countries want random, "non-challenge" inspections. Officials would be able to visit any biological facility at short notice merely to check that everything was in order--although this would not solve the problem of secret facilities. Negotiations on the BTWC have been stuck in a deadlock for four years because the US and the world's biotechnology and drugs industries will not agree to this (This Week, 8 March 1997, p 8). In late January, as the Iraqi crisis deepened, American President Bill Clinton announced he would support limited non-challenge inspections to clarify unclear declarations. But he explicitly rejected random visits.

Yet in Iraq, UNSCOM has shown how effective these can be. Former UNSCOM chief Rolf Ekeus stressed in 1995 that random visits to set up a monitoring programme were crucial. "It was during the build-up of the monitoring structure that [UNSCOM was] able to detect Iraq's concealment of its hitherto secret biological weapons programme," he said. Visits to food processing plants and vaccine factories turned up undeclared fermentation equipment and laboratories with more production capacity than had been admitted.

The Pharmaceutical Research and Manufacturers of America (PhRMA), which represents American drugs companies, maintains random inspections would "expose industry to the loss of its legitimate competitive trade secrets". (It is also worried that an inspection for biological weapons would be disastrous for a company's public relations.) But Lynn Klotz, who chairs the industry section of the FAS's biological weapons group, says that inspection techniques exist that could protect legitimate secrets without hindering verification. DNA probes that screen for specific DNA sequences, possibly coupled with the polymerase chain reaction, as well as immunoassays, which use antibodies to reveal specific molecules, "are the leading candidates for use in a compliance regime".

Klotz says these techniques would need to be developed further before the BTWC could use them. But once they were ready, factory managers could supervise the tests at every step, protecting legitimate secrets without hindering the inspectors. For example, instead of taking live microorganisms out of the plant, a company would kill sampled organisms in front of inspectors and scramble the DNA enough to protect proprietary genes without disguising the species. The inspector could then run either PCR or immunoassay tests on the dead organisms with portable kits.

The Chemical Weapons Treaty, which came into force last year, already allows random inspections, with "managed access" guidelines to protect industry. Klotz says these could be adapted for biological plants. PhRMA complains that random inspections would pose an unnecessary burden on industry. But Graham Pearson of Bradford University, former head of Britain's biological defence programme at Porton Down, estimates that under the verification regime now being proposed, a plant would be inspected only every two years--"about what national safety inspectors do already".

Supporters of random inspections say that the BTWC's members have little time to make the treaty effective because biological production techniques are constantly improving. They are hoping that it will not take a lethal attack from a rogue state such as Iraq to make the US change its mind.

Department of Peace studies, University of Bradford--Analysis of the current state of verfication negotiations under the Biological Weapons Convention, plus relevant UN documents and UNSCOM reports

Federation of American Scientists--position papers and comprehensive biological weapons links

Stockholm International Peace Research Institute--Chemical and Biological Warfare Project

Battlefield of the Future--21st Century Warfare Issues--A US Air Force book

The Henry L. Stimson Center--A US think-tank on technology and policy, including biological weapons.

LINKS FOR MORE INFO. ON BIO-TERRORISM & FAQ's:

ANTHRAX FOR DUMMIES:

http://student.biology.arizona.edu/honors98/group1/Intro/Intro.html

http://www.deskmedia.com/~reggie/Anthrax/faq.html

http://www.hopkins-biodefense.org/