Anthrax alert after spores found in US sorting office

Washington is on anthrax alert after the possible presence of deadly spores was detected during routine tests at a US navy mail-sorting office yesterday.

The sorting office and 11 public post offices were shut and five employees at the navy facility were offered the antibiotic ciprofloxacin, while authorities conducted follow-up tests to confirm whether anthrax was indeed involved.

Officials warned that even affirmative tests could prove to be false positives. In any case, the low level of spores indicated by the field tests meant that that the risk was far less than in October 2001, when a series of anthrax attacks killed five people, including two Washington postal workers, and left 17 others seriously ill.

There was no evidence that any of the 1,500 other postal staff at the closed offices had been exposed, officials said, and none has been offered antibiotics.

A navy spokesman said the closures had been decided "out of an abundance of caution" while tests for contamination were carried out.

After field tests, eight samples were sent to the US army's biological warfare defence centre at Fort Detrick, Maryland, for examination. One sample tested positive for anthrax, but seven were negative.

In October 2001, letters containing anthrax spores were sent to news media offices in New York and Florida, and to the Washington offices of two senators, including Tom Daschle, who was the Democratic majority leader. Those responsible have not been caught.