Anthrax investigation is stepped up

An investigation into how a New York hospital worker died from inhalation anthrax is being stepped up.

Kathy Nguyen died a day after being confirmed as suffering from the most lethal form of the infection, becoming the fourth to die as a result of the anthrax outbreaks.

But Ms Nguyen, who had survived the Vietnam War before coming to America, was not a media or postal worker and had no known contact with contaminated mail, raising fears the whole mail system is at risk of spreading the spores.

Her death fuelled fears of cross-contamination, where envelopes have come into contact with an anthrax-laced package and themselves become infected.

Concerns grew as a colleague of the dead woman was treated for a suspicious lesion which doctors fear may be anthrax.

And there was further mystery as a 51-year-old accountant in New Jersey was confirmed as suffering from skin anthrax, despite not having any memory of handling any suspicious packages and not being in a post office for six months.

The woman, who has not been named, worked in West Hamilton, New Jersey, where the three anthrax-laced letters which have been found were postmarked but had no connection with them or the postal service.

The investigation into Ms Nguyen's death included tests at the Manhattan hospital where she worked as a stores clerk and at her home but they failed to find traces of anthrax.

One possible find on her clothing is undergoing further testing, and investigators are trying to trace her steps over the last two weeks in a bid to find the source of the spores.

The wider investigation into who is sending the spores in the post is proving fruitless, attorney-general John Ashcroft admitted. "We do not have progress to report," he said.