WASHINGTON -- A New York hospital worker died on Wednesday of inhaled anthrax in a mysterious case that has baffled officials trying to find the source of the germ warfare agent that has killed four people this month in the United States.
The 61-year-old Vietnamese immigrant's death, the first one not linked to the postal service or the media, has also raised questions over whether the outbreak of anthrax since the Sept. 11 attacks might be more widespread than originally thought.
Tests at the woman's home in the Bronx and at the Manhattan Eye, Ear and Throat Hospital where she worked have so far proved negative for anthrax, authorities said.
Since Sept. 11, when hijacked planes were rammed into landmark buildings in New York and Washington killing more than 4,800 people, there have been 16 confirmed cases of anthrax and most of those were identified as coming through the mail.
New Jersey acting Gov. Donald DiFrancesco reported a new case on Wednesday of skin anthrax in a postal worker employed at a facility near Camden, which would bring the total number infected with anthrax in the United States to 17.
New York City Health Department spokeswoman Sandra Mullin said the Bronx woman, who has been identified as Kathy Nguyen, worked in a storage supply room at the hospital but it was not yet known how she came into contact with anthrax.
"She died early this morning, but I do not have any other details at this point," Mullin said.
The White House called the death of the hospital worker a cause for concern and expressed the president's condolences and sympathy to the woman's family.
"This is an event of concern and the president is discussing it with his team," White House spokesman Ari Fleischer told reporters.
Fleischer said tests at both the woman's home and her office had proved negative for anthrax and that the FBI was intensively investigating the case.
Authorities were also conducting an autopsy to learn whether the bacteria that infected the woman was related to those involved in other recent anthrax deaths, he said.
Nguyen's death will make it even more difficult for investigators to track down the source of her disease and to trace the last days of her life, which letters she opened, where she visited and whether she noticed anything suspicious.
Neighbors told local television that the woman, who left Vietnam for the United States in the 1970s, lived a quiet life and did not have any family in America.
Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases which is part of the National Institutes of Health, said the New York case was more perplexing than other cases so far.
"To have a situation where she gets inhalation anthrax and no evidence thus far in the place where she worked of there being anthrax, makes this a very puzzling mystery," Fauci told NBC's "Today" show.
"All bets are off and we really need to do -- the public health officials, the forensic group -- have to do a full court press on trying to track this down. This is critical," Fauci said.
Another case in New Jersey, where a female book-keeper has the skin form of the disease, has raised questions about whether she was a victim of "cross-contamination" in which spores from an anthrax-laden envelope contaminated other letters in the postal system.
The woman works in Hamilton township where several postal facilities have been contaminated with anthrax and Fauci said it was "not far-fetched at all" that she received a letter that was cross-contaminated.
Hamilton Township Mayor Glen Gilmore told ABC's "Good Morning America" show the woman had received a lot of mail recently because she was planning her daughter's wedding.
"The cross-contamination seems to be the most likely explanation," he said. "We are hoping there won't be any more. There are others who are being monitored and we are hoping for the best," he added.
In the early days of the crisis, public health officials tried to assure people that they could only contract anthrax if they came into contact with large numbers of spores and that spores were unlikely to travel through envelopes.
Fauci said he was "uncomfortable" with fixed numbers when looking at how many spores it would take to infect people with inhalational anthrax.
"I am quite frankly uncomfortable with this empirical number of 8,000 to 10,000," said Fauci, referring to the number of spores frequently cited by experts when looking at how many spores it would take to get inhalational anthrax.
"If you had 50,000 spores, that's no question that that could do it. If you have one or two or three, most people feel that that won't do it. But it's the area in between that's the real gray zone now that has people scratching their heads," he said.
Traces of anthrax have been found in several government buildings in the capital, including the Supreme Court, the State Department and the health department.
Three letters, including one addressed to Senate Majority Leader Tom Daschle, have been identified as containing anthrax, and more than 200 postal facilities are being tested. Officials have not discounted that there might be more letters circulating that contain anthrax.
