Other Agents Are Worse!

Monday October 22 3:34 PM ET
Think Anthrax Is Scary? Other Agents Are Worse

By Maggie Fox, Health and Science Correspondent

WASHINGTON (Reuters) - Americans may be suffering from ''anthrax anxiety'' now, but attackers who want to wreak biological havoc have a range of other, often more horrifying agents to choose from, experts say.

Smallpox is highly contagious and a particularly horrible disease, botulinum toxin could be sneaked into water supplies and paralyze thousands and plague is easily spread and evokes unpleasant reminders of medieval epidemics.

Bioterrorism and biological warfare experts have for three years been sounding increasingly urgent warnings about the risk of a germ attack and had finally started getting government funding to increase vaccine doses, stockpile antibiotics and explore various treatments for deadly hemorrhagic fevers.

They had compiled an ``A'' list of likely germ agents to be used in attacks, topped by anthrax.

Anthrax is considered by military and bioterrorism experts to be the weapon of choice because it is so deadly when inhaled, with up to a 90-percent death rate; it is relatively easy to get hold of; the spores are stable and can be dispersed by anything from a letter to a bomb; and because the symptoms look harmless until it is almost too late to treat it.

But anthrax is not easy to process into a usable form, is easy to treat with antibiotics and is not contagious.

SMALLPOX IS CONTAGIOUS AND DEADLY

Lots of other diseases are very contagious, including smallpox. A global vaccination program wiped it out in 1977, but the variola virus that causes smallpox is considered a good germ warfare weapon because it kills 30 percent of its victims, perhaps with a higher rate of fatalities if it is inhaled.

Everyone born before 1972 was vaccinated, but experts say the immunity has probably worn off for most.

``Although smallpox has long been feared as the most devastating of all infectious diseases, its potential for devastation today is far greater than at any previous time,'' the Working Group on Civilian Biodefense, made up of 25 doctors and researchers who have been studying biological warfare for years, said in a report published in the Journal of the American Medical Association (news - web sites) in February.

The U.S. Centers for Disease Control and Prevention (news - web sites) (CDC) says it has 15 million doses of smallpox vaccine -- but some experts say the true amount could be as little as half that because the vaccine may have degraded while in storage.

Tests are underway to see if the vaccine stockpile can be stretched by diluting it and work has begun on making a new vaccine. The U.S. government has said it wants to build up a supply of 300 million doses, just in case.

The vaccine, if given quickly enough after infection, can prevent a patient from becoming mortally ill.

PLAGUE NOT A THREAT OF THE PAST

Plague is another infectious disease that bioterrorism experts have been warning about. It infects between 1,000 and 3,000 people around the world every year, including a few in the United States, and also has a more dangerous inhaled form called pneumonic plague.

Spread by fleas carried by rodents, plague is caused by the Yersinia pestis bacteria.

The first signs of illness in pneumonic plague are fever, headache and a cough that brings up blood. Untreated, the pneumonia can kill but several antibiotics can stop the infection, including streptomycin and tetracycline.

Like smallpox, plague can be spread from person to person through invisible, infected droplets of saliva.

Tularemia, sometimes called rabbit fever, is another animal disease that occasionally infects people around the world.

Symptoms start within 1 to 10 days after exposure, with a high fever and perhaps a blister if the infection came through the skin. Experts say tularemia bacteria could be spread in an airborne explosion or perhaps by something like a crop duster.

It can kill but antibiotics work against tularemia.

Then there are the hemorrhagic fevers, from the well-known Ebola (news - web sites), to Argentine hemorrhagic fever, Lassa fever, Rift Valley fever, Crimean-Congo hemorrhagic fever and tick-borne encephalitis -- all caused by viruses.

DEADLY VIRUSES

Patients can bleed under the skin, out of the mouth, eyes and ears, and can die of shock. With the exception of yellow fever and Argentine hemorrhagic fever, no vaccines have been developed against any of the viruses, which are contagious and can be spread by insect bites.

Botulinum toxin, made by the Clostridium botulinum bacteria, is perhaps best known these days for its use by plastic surgeons, who inject tiny amounts to freeze muscles in the face and reduce some wrinkles.

But botulism is also a deadly form of food poisoning, causing severe paralysis and death.

Symptoms start after 6 hours to 2 weeks and include double or blurred vision, drooping eyelids, slurred speech and muscle weakness that descends from the shoulders to the legs.

``Botulinum toxin poses a major bioweapon threat because of its extreme potency and lethality, its ease of production, transport and misuse, and the need for prolonged intensive care among affected persons,'' the Working Group on Civilian Biodefense said.

``Botulinum toxin is the most poisonous substance known. A single gram of crystalline toxin, evenly dispersed and inhaled, would kill more than 1 million people, although technical factors would make such dissemination difficult.''

Botulism is not contagious and the CDC has some antitoxin to treat it.

Japan's Aum Shinrikyo cult tried to use botulinum toxin at least three different times, according to the report. ``These attacks failed, apparently because of faulty microbiological technique, deficient aerosol-generating equipment or internal sabotage,'' the working group said.

The group got the botulinum toxin out of the soil.