Ames strain
The Ames strain is one of 89 known strains of the anthrax bacterium. It was isolated from a diseased 14-month-old Beefmaster heifer that died in Sarita, Texas in 1981. The strain was isolated at the Texas Veterinary Medical Diagnostic Laboratory and a sample was sent to the United States Army Medical Research Institute of Infectious Diseases. Researchers at USAMRIID mistakenly believed the strain came from Ames, Iowa because the return address on the package was the USDA's National Veterinary Services Laboratories in Ames and mislabeled the specimen.
The Ames strain came to wide public attention in association with the 2001 anthrax attacks when seven letters containing it were mailed to media outlets and US Senators on September 18, 2001 and October 9, 2001.
Because of its virulence, the Ames strain is used by the United States as somewhat of a gold standard for development of vaccines and testing their effectiveness, starting in the 1980s, after work on weaponizing the Vollum 1B strain ended and all weaponized stocks were destroyed after the end of the U.S. biological warfare program in 1969. The Ames strain is a monomorphic disease, meaning it mutates slowly, if at all.
