In New York, on the CBS Evening News, medical correspondent Elizabeth Kaledin had the latest on the baffling case of a hospital worker who died Wednesday of inhalation anthrax.
Just like the blurry old photograph of Kathy Nguyen, the picture of how she was exposed to enough anthrax to kill her is not coming into focus.
She was a person of unwavering routines, neighbors say, kept an immaculate apartment, took the number 6 subway line every day, lived alone after a divorce, and worked hard.
"It's not like Kathy was a person who visited a lot of people and traveled a lot," said neighbor Anna Rodriguez. "She concentrated on work and home."
Though tests of her home and the hospital have come up negative, they continue to be scoured for clues. Anyone she was friends with or even spoke to is fair game.
"What about her personal life? Where does she go? Who does she interact with?" asked Dr. Anthony Fauci of the National Institutes of Health.
But so far the lines of inquiry are leading nowhere and health officials are stymied.
Compounding the mystery, two potential leads have dried up: Preliminary tests for anthrax on a co-worker at the hospital who had skin lesions have come back negative, as did tests suggesting there might have been anthrax spores on Kathy Nguyen's clothes.
The only thing tests have revealed for certain is that the anthrax found in Kathy Nguyen's body is the same strain found in the letters sent to the media and Senate Majority Leader Tom Daschle.
"All of them have basically been indistinguishable from each other," said Dr. Stephen Ostroff of the Centers for Disease Control and Prevention.
The difference this time is critical: There's no postmarked source and the anthrax could basically have come from anywhere in this quiet woman's world.
Dr. Ostroff also told the Early Show that the tests on Kathy Nguyen's clothes had been so sensitive that they initially gave researchers a "false positive" result. He added that he is not worried about the anthrax found in Kansas City and Indiana, because both sites are linked to the contaminated Washington, DC, facilities: This is not a new outbreak.
When speaking about Kathy Nguyen's anthrax being the same strain as the other cases, he said, "It means we're dealing with one source with everything we've seen," starting with the initial anthrax found in Florida.
He went on to say that we will need good epidemiological detective work to find out how Kathy Nguyen was exposed, as she passed away before anyone could talk to her.
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