Natural Cause Appears Unlikely in 2 Anthrax Cases
From The New York Times
October 9, 2001
"The one thing that's reasonably certain," Dr. Spertzel said, "is that the
Florida case is intentional."
By NICHOLAS WADE
W ith the discovery that a second
person in Florida has breathed
anthrax spores, experts on the disease are
finding it hard to come up with a plausible
natural explanation. Though they think such
an explanation may still emerge, they are
leaning toward the possibility that the spores
were deliberately spread.
Anthrax occurs from time to time in animals
but is rare in humans, at least in the United
States. People who handle hides or
carcasses of infected animals occasionally
catch the disease through the skin, in a form
known as cutaneous anthrax.
Inhalation anthrax, contracted by breathing
spores of the bacterium, is even rarer. Only
18 cases have been reported in the United
States in the last century, and all are
believed to have originated from special
environments where airborne anthrax spores are common — bone meal
plants or wool sorting factories, for instance, or laboratories studying the
organism.
Neither Robert Stevens, who died of inhalation anthrax last week, nor
Ernesto Blanco, a co-worker who has now been found to have anthrax
spores in his nasal passage, is yet known to have visited any such place. Nor
is the American Media building in Boca Raton, Fla., where both of them
worked, known to have ever been home to such activities.
Spores of the anthrax bacterium can last for years in the soil and are often
breathed in by grazing animals, which can then contract the disease. But
another odd feature of the Florida cases is that anthrax is not at present
endemic in the United States east of the Mississippi.
One case of inhalation anthrax in a Florida office building would be surprising
enough; two are even harder to explain. "It's a mind-stretching coincidence
that doesn't fit the pattern of any known natural outbreak," said Dr. Matthew
S. Meselson, an expert on biological warfare at Harvard University.
Dr. David Walker, an anthrax expert at the University of Texas Medical
Branch at Galveston, said he had "a hard time making this into a natural
exposure," though he added that "no one should jump to any conclusions"
until a lot more evidence was gathered.
Dr. Martin Hugh-Jones, an anthrax expert at Louisiana State University, said
that in those rare cases where inhalation anthrax existed, it occurred in wool
and hair mills and among renderers or people handling hides. "That's why this
is so odd," he said. "It's a Joe Blow working in an office."
Several experts have speculated about possible natural routes of transmission
in the Florida cases: perhaps a dead infected animal was trapped in the
American Media building's air ducts, or Mr. Stevens might have brought an
infected leather item into the building and then sniffed and shaken it.
But inhalation anthrax is not known to have spread in those ways in the past.
Nor do experts believe that inhalation anthrax might have occurred
sporadically in Florida but gone undetected by being dismissed as
pneumonia. "Somebody might not figure out right away that it was anthrax,
but I doubt they would call it pneumonia," said Dr. Glenn Songer, a
veterinary anthrax expert at the University of Arizona. "When you take into
account the pathology and other signs, there is just nothing else like it."
Florida health officials said one sample from the American Media building,
taken from Mr. Stevens's keyboard, had tested positive for anthrax. Dr.
Walker said the keyboard sample could not have come from Mr. Stevens,
because infected people do not breathe out spores. They carry the bacterium
in their blood, but the bacterium does not form spores, its infectious form,
until after the patient's death.
Because spores are not exhaled, anthrax is not spread from person to
person. So experts believe that Mr. Stevens and Mr. Blanco must have been
infected independently from the same source.
Several experts on anthrax who have considered the possibility of deliberate
spread believe that it would be difficult though not impossible for an amateur
to concoct a lethal preparation of anthrax, and that spreading it efficiently
would be more difficult still.
Provided a source of anthrax can be found, the bacillus can be brewed up in
kitchen conditions and made to form spores. The spores are highly
dangerous if breathed in, but simple precautions will protect the brewer.
On the other hand, the Aum Shinrikyo sect in Japan, with many resources
available to it, tried hard to make an infectious anthrax preparation and
failed.
William C. Patrick 3rd, a maker of germ weapons for the United States
before President Richard M. Nixon renounced them in 1969, said the
Florida incident appeared to be crude bioterrorism. "It looks like a poor
grade of product." he said, "and poor disseminating efficiency."
Agreement came from Richard Spertzel, former chief of United Nations
biological inspection teams in Iraq.
"The one thing that's reasonably certain," Dr. Spertzel said, "is that the
Florida case is intentional."
nytimes.com |
