Remember Anthrax?

Part 2

David Tell

April 20, 2002 12:00 AM

6) What's going on here? Is it Ames or isn't it?

Insofar as any of them feels sure of the answer, none of the scientists now working with the government will state it unambiguously, in part because they are concerned for the security of a massive ongoing investigation. Even were security not a concern, however, the question whether they are dealing with "the Ames strain" would still be a vexed one, for two reasons. First, "strain" is a word that has no fixed, technical meaning: Any set of microbes with closely related genetic characteristics gets called a "strain," but how closely related they must be--at what level of analysis should a set of microbes be subdivided into "strains"--is a subjective judgment. Is your second cousin "family" or merely distant kin?

Then there is the peculiar nature of anthrax itself. Anthracis is the world's most molecularly homogeneous bacterial species. As recently as 1995, every laboratory isolate ever tested appeared to be genetically identical, and only three of them had been labeled strains. There was Sterne, named after the South African researcher who developed veterinary medicine's still-standard anthrax vaccine. There was Vollum, originally recovered from livestock in England and a staple of the U.S. bioweapons program in the 1960s. And there was Ames, so dubbed by a USAMRIID scientist in 1981 (for the town in Iowa, though the sample actually originated in Texas). The Sterne strain was sui generis; it didn't cause disease. But no one knew exactly why, and the three strains remained genetically indistinguishable.

In 1996, a group of researchers at a Veterans Administration hospital in North Carolina were the first to announce the detection of meaningful differences in the DNA of various anthrax isolates; anthracis, they thought, was a species encompassing five distinct genetic subgroups. Over the next few years, building on this work, Dr. Paul Keim of Northern Arizona University in Flagstaff examined hundreds of anthrax samples from a collection maintained by Louisiana State University veterinarian Martin Hugh-Jones and further refined the bacterium's phylogeny: He found 89 unique genomes--strains, if you dare--in six major families of anthracis. Then, in 1999, Tim Read of the non-profit Institute for Genomic Research in Rockville, Maryland, published a full map of the Ames strain's main chromosome on the Internet--all the DNA letter-strings for nearly 6,000 genes. Using Read's data, Keim has since located at least 50 places along the anthrax genome where various strains diverge, and he believes he has positively fingerprinted more than 100 such strains in his own ballooning archive of bacteria.

Keim and Read are both heavily involved in the current investigation. Read has completed another full sequence of anthracis DNA, this one taken from Bob Stevens, last fall's first fatality. Keim has compared that roadmap with Read's previous, Ames-strain diagram. The two samples are said to be a match.

But they can only be a match within the limits of Keim's existing classification system for anthrax. And back in the fall, before they stopped talking to the press so frequently, he and Read were quite candid about what those limits entail. Bacillus anthracis mutates into separate strains at a glacial pace. It takes maybe a million generations before even a single piece of its DNA is altered. And any given isolate of the bacteria finishes only a few hundred of those reproductive cycles during each active life span, while infecting an animal or human host. Then, if it's lucky enough not to be killed by antibiotics or incinerated with its victim's corpse, an anthrax colony hibernates in sporulated form for decades at a time. It is because their opportunities for genetic development have been so few and far between that many of the anthracis strains Paul Keim believes he has identified are separated by just a handful of DNA nucleotides--out of more than five million in the bacterium's full genome.

Which means, Keim admitted to Science magazine back in November, that many of his putative strains cannot be distinguished from one another outside the margin of error for current DNA sequencing technology: one misread nucleotide in every 100,000 examined. Around the same time, asked by an NPR radio interviewer whether it would be "possible to find out who sent the anthrax, where it came from, [by] doing gene studies of it," Tim Read paused a moment--and said, "I don't think so."

7) Assuming that it were possible to match last fall's anthrax with the Ames strain, would that mean it had to have come from an American laboratory?

No. The bacterial culture that Army biologist Gregory Knudson called "Ames" in 1981 came from a 14-month-old, 700-pound Beefmaster heifer that had recently died on a ranch in Jim Hogg County, Texas. So far as modern science can determine, an identical form of anthracis continues to widely contaminate the soil in south Texas. In 1997, 16 years after the Jim Hogg case and hundreds of miles to the northwest, Ames is known to have killed at least one goat--and to have sickened two ranchhands who cut open the poor beast's stomach and poked around inside before storing the carcass in a kitchen freezer. Ames, as the CDC correctly asserts, is a naturally occurring bacterium. Want some? "I'd look for a dead animal," LSU's Martin Hugh-Jones advises. "You could just take some blood from the animal, some tissue, and swab and grow it up on blood agar--nothing easier. . . . I'd say first-year college microbiology."

You wouldn't even have to make a trip to Texas. Or be in the United States at all. Very closely related strains of anthrax--again, within the margin of DNA sequencing error--have been recovered from infected livestock in Argentina, England, South Africa, India, Australia, and China.

8) Really, though: Isn't it more likely that what we're talking about was stolen or cloned from a pre-existing laboratory stock?

Yes, but that doesn't help narrow things down much, either. Barbara Hatch Rosenberg's website lists Canada's DRES and a place called Porton Down in England as the only foreign installations known to keep Ames in their collections. Her list is woefully incomplete. Porton Down alone has openly acknowledged sharing Ames cultures with its associated public health agency, the Centre for Applied Microbiology and Research. And that outfit in turn has acknowledged distributing Ames to an unspecified number of private researchers.

What's more, in March of last year a group of French scientists at the Centre d' tudes du Bouchet published a report on experiments they'd conducted with their own Ames sample. And explained that they'd collaborated on those experiments with a second French laboratory at the University of Paris. And expressed gratitude for shipments of Ames they'd received from a third French laboratory, the Institut Pasteur. And from a fourth French laboratory at the Agence Fran aise de S curit Sanitaire des Aliments. And from one Dr. Mats Forman of Sweden, too.

The stuff is all over the place. It is almost certainly held in one or more Russian depositories. According to an elaborate forensic analysis sponsored by the National Academy of Sciences in 1998, the accidental 1979 explosion of a Soviet biowarfare factory in what was then Sverdlovsk released no fewer than four separate strains of anthracis into the atmosphere, one of which is now grouped in the same subtype as Ames. At its height in the early 1990s, the Soviet germ-weapons program, Biopreparat, had 2,000 scientists working exclusively on anthrax. Those few of them who remain employed by successor agencies are currently paid $100 per month to maintain custody of laboratory facilities like the one in Obolensk--which is critically delinquent in its payments for the electricity necessary to keep 3,000 different anthrax isolates, the world's largest collection, safely on ice.

All of which makes penetration of the wobbly Russian biodefense establishment--by rogue nations or terrorist organizations--a worrisome and real possibility. Iran, for example, is known to have recruited a number of disgruntled or indigent Russian military biologists. Saddam Hussein, on the other hand, is not known to have bagged any Russians.

But he may not need to. Top Iraqi scientists Nassir Hindawi and Abdul Rahman Thamer first tried to acquire a sample of the Ames strain from Porton Down in 1988. They were turned down, but over the next two years they did manage to purchase an enormous quantity of anthrax-ready biological growth medium from a British commercial supplier. And nine other strains of anthracis from the Institut Pasteur and an American company now located in Manassas, Virginia. And at least two variants of the intensely pathogenic Vollum strain from...who knows where, and in addition to who knows what else.

In late November, a "microbiologist who has studied Ames" told the Washington Post he thought "the probability that [the Iraqis] don't have the strain is near zero."

9) Surely the FBI has some substantial reason to discount such fears and focus its attention on a domestic suspect?

That could well be, but if so they're keeping it to themselves.

There is purely circumstantial though highly suggestive evidence that might seem to link Iraq with last fall's anthrax terrorism. The U.N.'s former top bioweapons inspector in Iraq, Richard O. Spertzel, has told Congress about reports of a "cryptic September article in a newspaper run by Saddam's son, Uday" which promised that a "virus" would soon attack "the raven," apparently a Baath party curseword for America. Spertzel has also told Congress that Iraq has conducted military exercises simulating the dispersal of anthrax spores from crop-dusting aircraft--a subject in which both Mohamed Atta and Zacarias Moussaoui, the alleged "twentieth hijacker," are known to have expressed intense interest. Last June, one of Atta's September 11 confederates, Ahmed Ibrahim Al Haznawi, walked into a Fort Lauderdale, Florida, emergency room with a painless but inflamed one-inch black lesion on his lower left leg. In retrospect, Al Haznawi's attending physician, Dr. Christos Tsonas, is convinced that the wound was cutaneous anthrax. The Department of Health and Human Services' top bioterrorism expert agrees, as do two leading researchers at the Johns Hopkins University Center for Civilian Biodefense Strategies.

And so on. The FBI has hardly said a word about why it is inclined to mistrust or make light of such signals. And what little the Bureau has offered about why it prefers to focus instead on possible American suspects isn't especially persuasive, unfortunately.

FBI handwriting experts have somehow determined that the xerox-copied taunts included with last fall's anthrax letters--"We have this anthrax. You die now. Are you afraid?"--were written by a native English-speaker, though they note without venturing an explanation that "he" used only block lettering, with slightly larger block letters at the beginning of every noun. Might it also be that "he" wasn't a native English-speaker at all, but rather someone who grew up speaking a language--like Arabic--whose alphabet has no upper or lower cases? Someone whose experience with Romance-language script was limited to his temporary residence in, say, the one Western country where nouns are always capitalized? That would be Germany, once home to Mohamed Atta and any number of other al Qaeda operatives. It is not clear whether the FBI has considered this clue.

By contrast, the Bureau and its allied "home-grown terror" theorists have clearly given a great deal of thought--too much thought--to the fact that their suspect left no potentially incriminating personal marks on last fall's letters: no fingerprints anywhere on the envelopes or xeroxes, and no saliva on the envelopes' adhesive flaps. To Barbara Hatch Rosenberg, this indicates that the mailer was a spook-like U.S. government insider, someone with "training or experience in covering evidence." Similarly, and for the same reason, the FBI believes Anthrax Man exhibited a notably "organized, rational thought process in furtherance of his criminal behavior." Actually, though, all he exhibited was a bare minimum of human brain function and an animal instinct for self-preservation. Ask yourself: Would you be willing to touch with your bare hands, much less lick with your tongue, an envelope containing two billion spores of the universe's most dangerous bacterium? The question answers itself.

Speaking on background to reporters, FBI officials have repeatedly endorsed Professor Rosenberg's interpretation of the mysterious advisory included with two of the anthrax mailings--that their recipients should begin taking "penacilin." The misspelling, Rosenberg argues, is a deliberate feint intended to distract investigators from the truth, and the prescription itself is what should lead them back: The reference to penicillin means the perpetrator was an American scientist, knowledgeable about the clinical protocols for treatment of anthrax, and eager to cure those of his fellow citizens whom he was simultaneously making very sick. But it means nothing of the kind, in fact. No true expert, benignly inspired, would nowadays prescribe penicillin for an anthracis infection. Ever since Tim Read published his Ames-strain DNA sequence in 1999, American researchers have understood that the organism's genes encode a beta-lactamase enzyme that neutralizes penicillin. American public health agencies have responded accordingly. CDC bulletins, for example, specifically recommend against reliance on penicillin in cases of systemic anthrax toxemia.

The Miss Marple of SUNY/Purchase does no better when it comes to divining an overarching motive for last fall's bacteriological assaults. The deed was done by a Pentagon budget hawk who "must have realized in advance that the anthrax attack would result in the strengthening of U.S. defense and response capabilities," Rosenberg conjectures. "This is not likely to have been a goal of anti-American terrorists." And the anti-American terrorists who flew two Boeing 757s into the side of the World Trade Center, one week before the first New Jersey-postmarked anthrax letters were mailed--those people did not suppose their actions would provoke a massive American military response? Perhaps Mohamed Atta, too, was a rogue, right-wing subcontractor for the CIA? Rosenberg's logic is elusive.

Federal investigators, for their part, arrive at much the same conclusion, though by reverse direction. The anthrax mailings were insufficiently provocative, a "senior administration official" has told the Wall Street Journal, explaining his colleagues' basic assumption: "Al Qaeda is into mass casualties, not this junior-varsity, onesy-twosey terrorism." This would make the suspect's identity contingent on the body count he achieved, something he could not possibly have predicted; the logic here seems nonexistent. What if the anthrax mailer had managed, as intended, to assassinate the majority leader of the United States Senate? Would that have been senior varsity enough for the FBI?

10) So who did send the anthrax? What are you saying?

Simply this: Based on the publicly available evidence, there appears to be no convincing rationale for the FBI's nearly exclusive concentration on American suspects. And the possibility is far from foreclosed that the anthrax bioterrorist was just who he said he was: a Muslim, impliedly from overseas, who thought the events of "09-11-01" were something to be celebrated--and who would have been doubly pleased to see "you die now."