America's anthrax scare was fuelled yesterday by reports of one new exposure and one new attack site. Meanwhile, experts expressed particular concern over the highly refined strain found in the office of the Senate Majority leader, Mr Tom Daschle.
New tests on his staff yesterday turned up 31 anthrax exposure positives, including two policemen, though to date none appear to have been infected.
Security officials on Capitol Hill extended their searches and the House agreed to close down for several days for tests.
To date, six confirmed anthrax attacks have been made:
on American Media in Florida;
on NBC and ABC in New York;
on Microsoft in Reno, Nevada;
on Senator Daschle in Washington;
on Gov Pataki in New York.
Four people have been confirmed to have been infected and one has died.
A new alert in New York was caused when anthrax was found in the Manhattan office of Gov George Pataki. Tests were ordered after the governor's secretary opened a suspicious letter and a positive was recorded in the security office. None of the staff tested positive but they and the governor were put on antibiotics.
Government sources said preliminary testing indicated the anthrax found in Senator Daschle's office had been refined enough so that it could be easily dispersed through the air. One official said the anthrax was in a purified form that could be used as a weapon. But Senator Daschle was more tentative, referring to the strain being particularly pure.
"This particular strain of anthrax is sensitive to all antibiotics," said Maj Gen John Parker, speaking on behalf of the Fort Detrick military lab technicians in Maryland who performed the tests on the samples. He described it as "common variety" anthrax.
Experts said the authorities appeared to be suggesting that while the Daschle strain had been milled to reduce the size of particles, rendering it more easily dispersable and more likely to cause pulmonary infection, it had not been genetically modified.
However, the Secretary of Health and Human Resources, Mr Tommy Thompson, in testimony to Congress, said: "There's no question this is a very serious attempt at anthrax poisoning."
Asked if the production of "weaponised" anthrax implied the involvement of an organisation with multi-million dollar facilities, even the resources of a state, Mr Thompson concurred but warned they still did not know enough about the strains they have found to draw such conclusions.
Senator Joe Biden said there was evidence of anthrax outside the Daschle office. The Justice Department released photocopies of the envelopes to Senator Daschle and to NBC's Mr Tom Brokaw, showing identical block letters and addresses written slanting to the right.
The envelopes showed both letters were postmarked from Trenton, New Jersey and both appeared to have the same type postage. The two letters contained similar anti-American and anti-Israeli language and a pro-Muslim statement.