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Are there other threats?

By David Abel, Globe Staff, 11/4/2001


How genuine is the risk?
Taking practical steps
Staying safe on the job
Handling new kind of stress
Talking with children
Is it just the flu?
What to do when in doubt
Hospital readiness
How the body fights back
Are there other threats?
Not all terror threats equal

How to talk to your kids
5 signs you need help
What works, what doesn't
How anthrax is diagnosed
Inside a bacterial invasion
In case of emergency...
Identifying a mail threat
Safety resources

Compare cold & flu to other bioterror threats:
Cold & Flu
Hemorrhagic Fever

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They may seem like a novel threat, but biological weapons have been part of warfare for more than two millennia.

In 190 BC, the Carthaginian general Hannibal hurled venomous snakes onto enemy ships. In the Middle Ages, the Roman emperor Frederick Barbarossa ordered his soldiers to drop diseased corpses into the water supply of his enemies. In 1650, a Polish artillery general filled hollow spheres with saliva from rabid dogs and fired them at his enemies.

Unlike nuclear weapons, which require a lot of money, material, and expertise, many bioweapons are easily produced. They can also be used stealthily, as with the recent anthrax-laced letters, making it difficult to identify the attacker. Known as a ''poor man's nuclear bomb,'' bioweapons are cheap to acquire and relatively easy to use to kill many people.

Because of their insidious nature - bioweapons kill indiscriminately, easily cross borders, and could infect the attackers themselves - the United States along with 140 other nations renounced their use in 1972.

Unfortunately, several nations, including signatories of the treaty, such as the Soviet Union, continued to produce, perfect, and stockpile bacteria and viruses that could be used as weapons. Thousands of tons of bioweapons are believed to be stored in countries throughout the world.

In 1999, a panel of medical, military, and law enforcement officials organized by the Centers for Disease Control evaluated the biological agents that posed the greatest danger as weapons. They judged them on four criteria: how efficiently the disease can be transmitted, how hard they are to produce and distribute, how well they can be defended against, and how likely they are to scare the public and produce widespread fear.

The panel ranked the potential bioweapons in three groups. Those ranked in the first group are the greatest threat. They are considered most likely to produce mass casualties and require the stockpiling of antibiotics and vaccines. Anthrax topped the list.

Here's a look at the other potential bioweapons the CDC says are the most threatening:

Smallpox. For centuries, smallpox ripped unpredictably through human populations, killing tens of millions. After an aggressive worldwide program to eradicate the disease, smallpox was finally wiped out in 1977 - one of the greatest successes in the history of public health.

But the smallpox virus is still feared as a bioweapon. Specialists contend Russia, Iraq, and North Korea maintain secret stockpiles. With enough sophistication, smallpox could be released as an aerosol. It could also be dispersed by terrorists who deliberately infected themselves and spread the disease by roaming through crowds. It has no proven treatment, and the virus could breeze through a small town or large city before anyone realizes it.

In June, a group of former government leaders staged a simulation of an outbreak of smallpox - and the results were not encouraging. Beginning with an imaginary terrorist release that infected 3,000 people in Oklahoma, the exercise predicted there would be hundreds of thousands of cases nationwide within 12 days and many others infected around the world.

Smallpox has an incubation period of about 12 days. During that time, the infected victim would develop a high fever and experience fatigue, headaches, and backaches. Soon, a rash would develop in the form of pus-filled, scabby sores. The majority of infected people survive, but live the rest of their lives covered with pockmarks.

The United States stopped routine vaccination for smallpox in 1972. Immunologists say a 29-year-old vaccination would be an unreliable defense against the disease.

A smallpox vaccine is still produced. The CDC estimates it has about 15 million doses of the vaccine, although some specialists say that number is inflated. In the event of an outbreak, vaccination would be required for anyone who came into contact with the person infected.

Since Sept. 11, the Pentagon has told Acambis PLC, a British company with offices in Cambridge and Canton, to boost the amount of vaccine it had already been asked to produce. In a year, the firm said, it should produce enough vaccine to treat every American.

Botulism. ''Botulinum toxin is the most poisonous substance known,'' according to a paper by the Johns Hopkins Civilian Biodefense Center.

The toxin comes from a bacterium that occurs naturally and thrives in low-oxygen conditions, such as food that has been improperly canned or stored. The toxin is relatively easy to produce and carry, and it can be spread by aerosol or by dropping it into the food supply, specialists say.

Iraq reportedly produced 5,000 gallons of toxin before Desert Storm and may still maintain a significant supply. For years the Soviets tested genetically refined versions of the toxin and ways to disseminate it through special spraying systems. And in the early 1990s, the Japanese cult Aum Shinrikyo tried but failed at least three times to disperse the toxin in aerosols in Japan.

The toxin attacks the nervous system. Within 12 to 72 hours, those exposed generally begin to feel symptoms such as blurred vision, nausea, lethargy, difficulty speaking, and muscle aches. Without quick treatment, victims become paralyzed and might die. Botulism sickens about 200 Americans each year. With treatment, according to the Centers for Disease Control, only about 8 percent of patients with botulism die.

Doctors treat the disease with an antitoxin. As with smallpox, the treatment must be administered as soon after exposure as possible. A regimen of antibiotics doesn't guarantee full recovery, and someone poisoned with the toxin probably will remain in intensive care for weeks or even months.

Plague. Plague is a naturally occurring bacterial disease transmitted by the bite of an infected flea. Also known as Black Death, plague ravaged the world during the Middle Ages, killing hundreds of millions of people in Asia and Europe.

Its ability to generate fear has not abated. In 1994, about 500,000 people fled Surat, India, to escape the emergence of plague there.

Such natural epidemics are increasingly unlikely today, as more of the world benefits from advances in living standards, public health measures, and antibiotics. But if used as a bioweapon, plague could be as deadly as it was centuries ago.

Both the United States and the Soviet Union created aerosolized plague particles that could be spread over a city by a special bomb or a plane similar to a crop-duster. A cloud of bacteria could set off a large outbreak of pneumonic plague, a highly lethal form of the disease that can be transmitted from person to person by coughing.

The first signs of the disease would show up one to six days after a victim inhaled the poisonous bacteria. Without quick treatment, the victims would suffer from fever, weakness, and bouts of coughing up blood. Kidney and respiratory failure would follow and a form of pneumonia would probably kill the victim within days. More than 50 percent of pneumonic plague victims die.

There is no vaccine, but several antibiotics can be used if given within one day after symptoms appear.

Tularemia. The tularemia bacterium has been studied for use as a weapon since World War II. Though it was never used, it became a part of the US military's inventory during the Vietnam War. Also known as ''rabbit fever,'' tularemia can be transmitted by tick bite or inhalation.

Although rare in nature, the disease has been in the news in Massachusetts: 18 cases have been reported on Martha's Vineyard in the past two summers.

If released by an aerosol in a dense, urban area, thousands of victims would probably develop a fever within three to five days, although it could take as long as two weeks.

''Due to the speed with which it could overwhelm an opponent's medical resources, leaving hospitals and physicians unable to cope with a flood of patients in need of constant treatment, tularemia was considered an ideal weapon for the battlefield,'' wrote Ken Alibek, the former director of the Soviet bioweapons program, in his 1999 book ''Biohazard.'' Alibek himself suffered from exposure to the disease while doing bioweapons research in 1983.

Like anthrax, the initial symptoms would be similar to the flu: chills, headaches, and fatigue. Without antibiotics, the disease would ultimately cause respiratory failure, shock, and death. Depending on the strain and the speed of treatment, tularemia kills 5 percent to 60 percent of its victims, according to Johns Hopkins University's Center for Civilian Biodefense Studies.

If caught early, tularemia is treatable with antibiotics. It is also relatively easy to disseminate, but it cannot be transmitted from person to person.

Hemorrhagic fevers. Described in gruesome detail in Richard Preston's book ''The Hot Zone,'' hemorrhagic fevers are diseases that cause the body's fluids to ooze out of tissues and orifices.

The best-known of the fevers is the Ebola virus, which kills 30 percent to 90 percent of all those who contract it. Other hemorrhagic fevers include Marburg, Lassa, yellow fever, and dengue.

Specialists say such diseases would be difficult to use as weapons because they're often unstable, highly infectious, and are likely to infect those who try to use them.

The Soviets tested Marburg, which they turned into a weapon after one of their biowarfare scientists died while researching the virus. Dengue has emerged in Cuba, and some dissidents there have suggested it came from the country's pharmaceutical plants, which have long been suspected of producing bioweapons.

A victim of Ebola would have a sudden, high fever, vomiting, diarrhea, chest pain, and internal and external bleeding two days to three weeks after exposure. Through direct contact with blood or other secretions, the virus can spread quickly and easily to others.

There are no known vaccines for Ebola, Marburg, or other hemorrhagic fevers, but like other bioweapons, if caught early enough, these fevers can be treated with antibiotics and antiviral drugs.

Other diseases. The potential bioweapons listed above were ranked by the CDC panel as ''Category A'' diseases, the most capable of producing mass casualties.

Category B agents include Q fever, typhus, viral encephalitis, brucellosis, and several other toxins that can be transmitted to large populations and could wreak havoc on the nation's public health system. As bioweapons, however, they are less likely to be as effective at killing.

Those in the third tier, Category C, are not considered to be immediate threats. The panelists cited diseases such as Nipah virus, hantaviruses, tick-borne hemorrhagic fever viruses, tick-borne encephalitis viruses, and multidrug-resistant tuberculosis as possible pathogens a sophisticated terrorist may try to use.

In a book published last year called ''Living Terrors,'' Michael T. Osterholm, an epidemiologist and bioweapons specialist who teaches at the University of Minnesota, was prophetic about the ''inevitability'' that biology would be used as a weapon in the near future.

''I do not believe it is a question of whether a lone terrorist or terrorist group will use infectious disease agents to kill unsuspecting citizens,'' he wrote. ''I'm convinced it's really just a question of when and where.''

Now we know the answer to both of those questions - and, unfortunately, he is not encouraging about the prospect of more dangerous bioattacks.

Still, as dire as the future may seem with new anthrax spores being found almost every day, know that all of the most lethal potential bioweapons are difficult to obtain and difficult to make into agents of mass destruction.

And even if a terrorist group does acquire them and refines them into weapons, it would be difficult for them to obtain enough to mount a massive attack.

This story ran on page 14 of the Boston Sunday Globe's Common-sense Guide to Keeping Safe on 11/4/2001.
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