An elderly woman, who lived on her own in an agricultural area Connecticut ,died of inhalation anthrax today,
The woman, aged 94, tested positive for the inhaled form of the disease in five separate tests.
More tests are being conducted by experts at the federal Centres for Disease Control and Prevention in Atlanta.
Mr Rowland said the woman lived in Oxford, a small rural community about 30 miles south-west of the capital, Hartford. She was originally treated for pneumonia and hospitalized last Wednesday.
"It's difficult to explain how the person contracted anthrax," Rowland said. "There is no evidence she contracted the disease as a result of a criminal act."
The FBI and state police have secured the woman's home and are conducting a criminal investigation, Mr Rowland said. The woman lives by herself and has a limited routine.
Across the United States, four people have previously died and 13 have been taken ill by anthrax since early October.
Joxel Garcia, the Connecticut health commissioner, said the state had received positive tests from the hospital Monday and immediately began conducting its own investigation.
Mr Rowland said there was no indication the woman was related to any government official or had any public activity that would cause her to be a target of terrorism.Reuse content