"Friendly fire" is the euphemism for troops shot down in error by guns from their own side.

It happened often in World War II and in Vietnam, but no incident of friendly fire among casualties of biological warfare has been widely reported — until lately.

On April 2, 1979, in the Soviet city of Sverdlovsk (now once again called Ekaterinburg), a sudden, mysterious epidemic took the lives of 96 people. Soviet authorities initially stonewalled, then claimed that the wave of deaths was an outbreak of anthrax infection, caused by "people . . . eating bad meat they bought from 'private butchers.'"

The anthrax pathogen, Bacillus anthracis, is endemic in cattle and other domestic animals. (See BioWorld Today, Nov. 20, 1997, p. 1.)

It was not the city's first brush with historic mass killing. In July 1918, Red Army guns shot to death Russia's Czar Nicholas II, his wife, children and servants. Only in the closing decade of the 20th century did DNA analysis identify the remains of these victims. (See BioWorld Today, Jan. 5, 1995, p. 1.)

An article in Science three years ago concluded "that the [Sverdlovsk] outbreak resulted from the wind-borne spread of an aerosol of anthrax pathogen, [and] that the source was the military microbiology facility," from which the deaths-by-inhalation were distributed in a downwind pattern.

Findings Hint At Manmade Outbreak

Now, even more sophisticated DNA forensic methods have confirmed that B. anthracis was indeed responsible for Sverdlovsk's 1979 Black Death. What's more, it shifted the burden of proof even further away from rotten meat and more toward a biological warfare accident, or release, of anthrax pathogens.

This latest scientific exposé appears in today's Proceedings of the National Academy of Sciences (PNAS), dated Feb. 3, 1998. Its title: "PCR analysis of tissue samples from the 1979 Sverdlovsk anthrax victims: The presence of multiple Bacillus anthracis strains in different victims."

The paper's co-senior authors are molecular biologists Paul Jackson, of Los Alamos (N.M.) National Laboratory, and Paul Keim, of Northern Arizona University, in Flagstaff.

They received 13 tissue samples from 11 of the 96 victims, collected by two Russian pathologists, Faina Abramova and Lev Grinberg, who were members of the team that autopsied the 96 deaths in 1979. Abramova and Grinberg are co-authors of the PNAS article.

That spectrum of bodily tissues comprised six from spleens, four from meninges, one lymph node, one lung and one anthrax vaccination site. "They are locations where anthrax was known to occur," Keim told BioWorld Today. "It comes down to what the physicians doing the autopsies wished to collect. But they made it possible for us to do our analysis."

Their DNA extraction technology, described in the paper, Jackson told BioWorld Today, "demonstrates the ability to interrogate forensic and veterinary samples in a way that, once more and more probes are developed, we'll be able to understand more and more about some things genetically than we do currently, by using other methods.

"Not only that," he pointed out, "but we can deal with dead samples, based on the genetic material that's there, so there's not a risk of culturing live materials."

The actual extraction method, he observed, "is the subject of another paper."

The team's initial purpose, Jackson pointed out, "was to show that the methods we had developed would work in real B. anthracis samples. It was more a proof of principle, but we were pretty surprised by some of the results."

He explained: "We did not expect to find a mixture of different anthrax strain categories in those tissue samples, because every other outbreak we've ever looked at contained only one of the pathogen's five known strains."

Flagstaff's Keim enlarged on this surprise element: "Anthrax," he recounted, "is a disease that's worldwide; ongoing epidemics exist. When we've analyzed samples from around the world, we find that in general a local epidemic will have a single strain. To find multiple strains in victims all at the same time was inconsistent with a natural outbreak."

From this finding he drew the tentative conclusion that "a biowarfare facility in Sverdlovsk released these anthrax strains, presumably by accident. How that accident occurred, and what went on inside, we don't know. A very simple explanation," Keim went on, "one of several, is that they had the accident while handling multiple strains, and all got released at the same time. Other possibilities are that they actually were using multiple strains in some type of a bioweapon cocktail, presumably to guarantee more efficacy."

The anthrax vaccine just ordered up to immunize U.S. forces in a repeat Gulf War, Keim pointed out, "is, to my understanding, efficient against all known strains of the pathogen. The U.S. Army Medical Institute of Infectious Diseases, at Fort Detrick, Maryland, has assured me that they've never found a strain that could defeat the U.S. vaccine."

He and his associates are working on the molecular epidemiology of anthrax, Keim said. "We have tissue samples from around the world. Literally, every part of the world is represented, except for Russia. I don't believe they've told us everything they know."

The Iraqi Connection

Keim alluded to a recent list in Newsweek of countries — "you could guess which" — involved in anthrax-based biowarfare. "Anthrax would certainly top the list for the Iraqis," he observed.

Britain's foreign secretary, Robin Cook, warned late last month that "Iraq admits to having had anthrax warheads for its long-range missiles before the Gulf War. What happened to these weapons is far from clear." Cook said Iraq is creating enough anthrax every week to fill two missile warheads.

Keim commented: "B. anthracis spores are incredibly resistant, which is why they are at the top of the bioweapon threat list. Anybody could make them, and they're stable for hundreds of years. You could pack a warhead full of these things, put it on a missile, and never worry about it."

Jackson observed that the detection methods he and his co-authors are developing could conceivably be used in the United Nations' search for weapons of mass destruction in Iraq, "to verify what we might find in the samples that anybody might want us to look at." *

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