She becomes the fifth person in the United States to die from anthrax since September.
Authorities are baffled as to how Ottilie Lundgren, who lived in a small rural community and rarely went out, contracted the disease. She was admitted on Friday with symptoms akin to pneumonia.
The Centers for Disease Control (CDC) confirmed the case after she tested positive for the disease in five separate tests carried out by the local health authorities.
Baffled
The north-east US state's governor, John Rowland, said: "It's difficult to explain how the person contracted anthrax."
"There is no evidence (she) contracted the disease as a result of a criminal act," he added.
The woman - the first new anthrax case in three weeks - lived in Oxford, about 30 miles (48 kilometres) southwest of the state capital, Hartford.
The previous victims of anthrax were a hospital worker in New York City, two postal workers in Washington and a photo-journalist in Florida.
Chile alert
There has also been another anthrax alert outside America. Authorities in Chile said on Tuesday they have found anthrax spores in a letter sent from abroad to a private business in the capital, Santiago.
And investigators have found traces of anthrax in two more US lawmakers' offices - those of Democratic Senator
Ted Kennedy of Massachusetts and Democratic
Senator Christopher Dodd of Connecticut.
All of those infected so far - 13 people, along with the five who have died, have been associated with the mail, the media or Capitol Hill, except for the New York hospital worker, Kathy Nguyen.
Domestic source
The BBC's correspondent in Washington, Rob Watson, says the US authorities had been hoping the outbreak of anthrax infections was over, despite their total failure so far to track down whoever is responsible for the attacks.
The disease can be spread by hoofed animals, although they rarely carry it in western Europe and the US.
This week's other apparent targets are more typical of the pattern which has so far emerged in the American anthrax cases.
A weekend environmental sweep of the Senate Russell Office Building in Washington found trace amounts of anthrax in the offices of Senators Kennedy and Dodd.
The investigation was ordered after a letter to Vermont Senator Patrick Leahy was discovered on Friday.
This letter raised to more than a dozen the number of Senate suites found with trace amounts of the bacteria.
Attorney General John Ashcroft has indicated that authorities believe that the anthrax is comes from a domestic, rather than an international, source .