Anti-bacteria machine brought in to sanitise mail

Mail to America’s capital was today being put through bacteria-killing irradiation machines, in the first step in a plan to prevent more anthrax attacks.

The American post office has bought equipment usually used to treat food for bacteria and is using it to irradiate the capital’s mail, killing off any anthrax spores concealed in letters or packages.

The move came as the scale of the anthrax outbreak continued to grow, with three people dead, four confirmed as suffering inhalation anthrax, the most serious form of the disease, at least seven extra people suspected of suffering from it, and seven diagnosed with cutaneous, or skin-borne, anthrax.

The latest case was at the State Department, America’s equivalent of the British Foreign Office, where a mail office worker in Virginia was confirmed as having inhalation anthrax.

The case raises fears that terrorists targeted the department, headed by ex-Gulf War general Colin Powell, and comes after traces of anthrax were found at the office which sorts the White House’s mail before it reaches the President’s mansion.

Postal chiefs now plan to spend up to £1.3bn on buying around 250 irradiation machines which will be installed within 18 months to kill bacteria on all mail, while it is treating mail by sending it to Washington immediately.

Thousands of postal workers are now receiving Cipro, the powerful antibiotic which prevents anthrax developing.

They include workers in Washington, where two of the bacteria’s victims worked at the central sorting office, and in New Jersey, where two mail workers have cutaneous anthrax, one has inhalation anthrax while one is being tested for it, and in New York, where at least two spore-laced letters were handled.

Also receiving the antibiotics are hundreds of workers at the Congress building, where an anthrax letter was sent to Tom Daschle, leader of the majority Democrats in the Senate.

A total of 28 people were confirmed as having been exposed to the spores when the letter was opened, while a journalist who was outside the office where it was opened is being tested for suspected inhalation anthrax.

The letter is being blamed for the deaths and infection of the postal workers, who are thought to have come into contact with spores which escaped from it as it went through sorting machines.

And it has raised fears that the attack is even more organised than had been first thought, as the spores sent to the senator were described as ‘‘concentrated and pure’’.

Two other letters have been discovered, one to the New York Post, where one worker, 30-year-old editorial assistant Johanne Huden, is suffering cutaneous anthrax and another, an unnamed mail worker, is being tested for possible infection.

America’s new director of homeland security, Tom Ridge, revealed the finding that the anthrax sent to the Senate was more potent and said: ‘‘This week we have received new information from laboratory tests.

‘‘It shows that the anthrax in the letter received in Senator Daschle’s office has some different characteristics.

‘‘It is highly concentrated, it is pure and the spores are smaller. Therefore they are more dangerous as they are easily absorbed in the respiratory system.’’

He added that preliminary tests on the New York Post samples showed it was less concentrated but added: ‘‘It is still highly concentrated.’’

The senate sample was specially milled to be the perfect size to float in the air, making it even more deadly, and there were reports the spores had been treated with a special chemical to keep them in the air for as long as possible.

Only America, the former Soviet Union and Iraq have the technology to treat anthrax with the chemicals.

But experts have warned that it is unclear how secure the former Soviet Union’s or Iraq’s supplies are, and it is also possible their scientists could have defected elsewhere.

The other anthrax-laced letter was sent to NBC newsreader Tom Brokaw in New York. Last night a second case of cutaneous anthrax was diagnosed at the broadcaster in an unnamed woman who handled the letter.

Erin O’Connor, 38, who handled the letter, already has cutaneous anthrax.

Anthrax was also found at the offices of tabloid magazine publisher American Media Incorporated, in Boca Raton, Florida, where British-born journalist Bob Stevens, 63, has died of the disease and one of his colleagues is recovering.

And there was also a find of anthrax traces at New York’s central sorting office, which handled the letters to NBC and the New York Post.

Two other people are being treated in New York for cutaneous anthrax.

They are Claire Fletcher, 27, from Sheffield, an assistant to CBS newsreader Dan Rather, and the unnamed seven-month-old son of an ABC producer.

But the Secret Service ruled out any possibility a letter containing salmonella sent to ex-President Bill Clinton was part of a bioterror campaign, and said it was probably from a crank.

The person or group behind the anthrax attacks has not been found and few leads have emerged in the case.

Attorney general John Ashcroft said: ‘‘We cannot explicitly link the recent anthrax letters to the September 11 hijacks.

‘‘Yet terrorists, people who were involved in, associated with or seeking to take advantage of the September 11 attacks, are sending this anthrax to our communities.’’