The new illnesses are challenging officials' theories about who might be vulnerable to bioterrorism, because the two women did not work for the U.S. Postal Service, government or news media, as have others sickened by the bacteria.
Investigators had believed that the outbreak of the rare disease in humans - 16 confirmed cases so far - could be explained by terrorists sending letters filled with anthrax spores to Congress and journalists. Postal workers may have become ill handling the letters, the theory went.
But Dr. Anthony S. Fauci, a top official at the National Institutes of Health, said yesterday that health officials are re-examining their assumption that the public stands little chance of contracting anthrax through mail delivered to their homes.
"Until yesterday, there was no evidence that there could be or is an individual in which there might be the reasonable question: 'Did they get infected from a piece of mail that went to their home?'" Fauci said at a news briefing. "That is being intensively investigated right now."
Tom Ridge, the U.S. director of homeland security, said yesterday that he believes that home delivery of mail poses little risk for most Americans.
This is especially true, Ridge said, if the public follows the Postal Service's advice to put aside any suspicious-looking mail and wash one's hands.
"We still think ... you ought to open your mail and you ought to use the postal system," Ridge said.
Twenty-five days after a photo editor at a Florida tabloid died as the first of three fatalities caused by the anthrax attacks, federal officials still do not know who spread the lethal bacteria or how it has turned up in so many government buildings.
In the District of Columbia, authorities said yesterday that investigators have found traces of anthrax in another post office - adding to a growing list of contaminated buildings.
The Friendship Post Office, at 4005 Wisconsin Ave. NW, received mail from the Brentwood mail-sorting center where investigators found anthrax this month. Four postal workers at the Brentwood facility were sickened with inhaled anthrax, two fatally. The center handled an anthrax-tainted letter sent to Senate Majority Leader Tom Daschle of South Dakota.
Along with the U.S. Supreme Court, the Hart Senate Office Building and other government facilities, the Friendship Post Office will be closed until health workers decontaminate it, officials said.
"It is exceedingly clear that the target of the terrorists in this situation was the three branches of government," said Dr. Patrick Meehan of the federal Centers for Disease Control and Prevention in Atlanta.
Traces of anthrax have also been found at a retail facility near Dulles International Airport in Virginia and in the mailroom of the U.S. Department of Agriculture Economic Research Service in Washington, officials said.
The woman, whose name was not released, felt chills and muscle aches Thursday. She went to Lenox Hill Hospital on Sunday, complaining of severe breathing problems, according to the New York City Department of Health.
"The woman is critically ill," City Health Commissioner Neal Cohen said at a news conference yesterday. "There is evidence that the inhalational anthrax has released a lot of toxins and done a lot of damage systemically, and at this point she is struggling for survival."
Her case is puzzling because investigators have not found an anthrax-laced letter that she might have opened, and she only occasionally handled mail as part of her job, health authorities said.
The woman worked in a basement stockroom. Until a renovation about two weeks ago, the stockroom was connected to the hospital's mailroom.
Dr. Jeffrey Koplan, director of the Centers for Disease Control, said the hospital worker cannot talk because she is on a respirator, so investigators are interviewing relatives and friends in hopes of learning how or where she might have been exposed.
Officials are investigating where she worked and what she did socially and recreationally, and what transportation she took, Koplan said.
"We are making no assumptions as to where this exposure occurred," Koplan said. "We are not making an immediate assumption that she was exposed at work or that it was a letter."
Stephen Ostroff of the CDC said: "The reason that this particular case is concerning is because it doesn't fit the pattern that we've seen with the other illnesses. ... There's no clear linkage with mail."
The hospital where she worked was shut down yesterday as investigators took samples in the building. Hundreds of workers and patients were being tested for anthrax and given antibiotics, city officials said.
A 51-year-old woman who works as an accountant for a Trenton firm and lives in Hamilton Township developed a lesion on her forehead Oct. 17.
After being hospitalized for testing, she was released Sunday. Biopsy results on Monday confirmed that she had the skin form of anthrax, according to health officials. She is taking antibiotics and doing well.
Investigators are looking into the possibility that mail that she opened might have been cross-contaminated by an anthrax-laced letter that passed through the Hamilton processing center, which is near her workplace.
The Hamilton center handled anthrax-tainted envelopes delivered to Daschle's office and to the New York offices of NBC News and the New York Post. Four postal workers at the Hamilton center have contracted cutaneous, or skin anthrax.
Health officials are also sampling the woman's home and office to see if anthrax spores might be there, CDC officials said.
The woman does not remember opening any suspicious mail, according to co-workers.
James Alfieri, a partner at her firm of Civale, Sylvestri and Alfieri, said she opens letters addressed to her and occasionally some for her clients and others in the office.
"I talked to her last night. She's doing really well and is sorry for all the commotion," Alfieri said.
In Baltimore, city health officials are planning to test at least 12 federal government mailrooms in the city for anthrax because they are concerned about a delay in testing by federal officials, said Dr. Peter L. Beilenson, Baltimore's health commissioner.
Time is of the essence, Beilenson said, because several hundred Baltimoreans who work in those facilities are taking a 10-day course of free antibiotics as a precaution.
After 10 days, Beilenson said, health officials won't know whether those people need further treatment unless they have results from the workplace tests.
"We have an ethical obligation to make sure that these [workplaces] are tested, so we're going to go ahead," Beilenson said.
Other developments in the anthrax investigation yesterday:
Sun staff writers Jonathan Bor, Heather Dewar and Ellen Gamerman, along with wire services, contributed to this article.