WASHINGTON, Oct 20: The anthrax strains discovered in Washington, New York and Florida are “indistinguishable” from one another, the US homeland security director said Friday as a New York Post employee became the seventh person in the United States to contract the disease.

“It does appear that it may have come from the same batch,” Tom Ridge said at a press conference in Washington. “It may have been distributed to different individuals to infect and disseminate into different communities.”

The head of the newly created cabinet-level agency added that federal investigators have tracked down the New Jersey mailbox from which anthrax-tainted letters were mailed to Senate Majority Leader Tom Daschle and NBC News television anchorman Tom Brokaw.

The seventh person to contract anthrax works as an assistant in the New York Post’s newsroom, opening mail there. Although she is believed to have contracted skin anthrax by opening letters, she did not remember receiving any suspicious mail, Post officials said.—dpa