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That was before Kathy Nguyen died. On Thursday, Oct. 25, the Vietnamese-born hospital worker came down with chills and muscle aches. She went to work Thursday and Friday at the stockroom of the Manhattan Eye, Ear & Throat Hospital on Manhattan's Upper East Side. But the symptoms worsened, and on Sunday she was hospitalized with severe breathing problems, fluid in her lungs, sputum tinged with blood and a 102[degree]F fever. By last Wednesday, Nguyen had succumbed to a galloping case of inhalational anthrax. She was 61.
What makes Nguyen's case so baffling is that she didn't fit any of the profiles of a potential anthrax victim. She didn't work in a post office or for the media, which have been the targets of at least three anthrax-laden letters. The stockroom where she worked adjoins the mailroom, and she did occasionally handle mail. But no suspicious letters turned up at the hospital. And tests have found no signs of anthrax either at her workplace or her apartment in the Bronx, where she lived alone. Nasal swabs of people who worked with or near Nguyen have come back negative as well.
In fact, after 17 cases and four deaths, officials are coming to the realization that they know little about anthrax in general and about this attack in particular. Anthrax spores have been detected at a widening list of sites. In the past week they showed up for the first time at a mailroom in the Washington, D.C., V.A. Medical Center; a postal facility in Kansas City, Mo.; a shop in Indianapolis, Ind., that repairs postal machines; a third New Jersey post office and a sixth in Florida; in four mailrooms at the Food and Drug Administration in Rockville, Md.; at a newspaper in Pakistan; and at the U.S. embassies in Peru and Lithuania.
But at the same time, the number of new anthrax infections has grown by only three--Nguyen's, and cases of skin anthrax that struck a New Jersey woman and a New York Post employee. Because the first two people evidently had no direct exposure to any of the known anthrax letters, nor were they known to have spent significant periods of time in the post offices that handled them, it has become increasingly hard to figure out what's going on. Maybe it's a lot easier to get the disease than the experts thought, or maybe some individuals are particularly susceptible. Maybe more letters went out than the authorities yet know about. Or maybe both women are the first victims of an entirely new form of attack that has nothing to do with the mail.
According to the conventional wisdom about anthrax, it takes 8,000 to 10,000 spores to trigger a case of inhalational anthrax. And while the letter that arrived at Senator Tom Daschle's office probably contained billions of spores, they would have to be aerosolized first--puffed into an inhalable cloud. That's easy enough to do in an envelope if there is even a small opening and enough pressure, such as that generated by a mail-sorting machine. Any gaps in the tape that sealed the Daschle letter, or even the porosity of the envelope, therefore, could explain the inhalational-anthrax cases at the post offices the Daschle letter passed through.
But that doesn't explain how a postal worker in the State Department mail-processing center got the disease or how Nguyen contracted it. Anthrax puffed from an envelope could easily settle on mail-processing machines--where spores have been found--or on other surfaces. They could also have settled on other letters, in what's known as cross-contamination. Anyone touching a cross-contaminated letter, especially someone with an open cut, would be at risk for skin anthrax--and in fact, the New Jersey woman's mailbox tested positive late last week, suggesting that this might be what happened to her.
But in order to be inhaled, cross-contaminated spores would have to be re-aerosolized, and that is hard to imagine, says William Patrick, a longtime Army biological-weapons researcher. "There's an electrostatic bond between the spore and the envelope," he says. "It takes a lot of energy to break the bond. They're just not going to be re-aerosolized in large enough quantities to provide an inhalation case." That would suggest that more than the three known letters have passed through the system. And given the tens of thousands of pieces of mail still impounded in Washington and New Jersey, some of them could still be there.
But it's also possible that the conventional wisdom is wrong. The only hard data on how many spores it takes to cause inhalational anthrax come from studies the Army did on monkeys in the 1950s. When the dose was 8,000 to 10,000 spores per animal, about half the monkeys died. But that doesn't prove that a lot fewer spores won't cause an infection. Says Philip Brachman, a professor of public health at Emory University who investigated a naturally occurring 1957 outbreak in Manchester, N.H., among millworkers who handled infected animal hides: "We don't know for certain what dosage of the organisms causes inhalation anthrax."