Short answers, pulled from the story.
Anthrax is an infection caused by the bacterium Bacillus anthracis or Bacillus cereus biovar anthracis. The bacterium normally rests in spore form in soil and can survive for decades or even centuries. Infection occurs through contact with the skin, inhalation, or intestinal absorption of spores.
Robert Koch, a German physician working in Wollstein (now Wolsztyn, Poland), first identified Bacillus anthracis as the cause of anthrax in 1875. He took a blood sample from an infected cow, isolated the bacteria, and introduced them into a mouse, demonstrating that the microbe caused the disease.
Anthrax presents in four main forms: cutaneous (skin), inhalation, gastrointestinal, and injection. Cutaneous anthrax accounts for more than 95 percent of cases and has a mortality rate of 23.7 percent without treatment. Inhalation anthrax carries a fatality rate that was 90 percent before 2001 and has since fallen to 45 percent. Gastrointestinal anthrax is fatal in 25 to 60 percent of cases depending on treatment timing.
Louis Pasteur developed the first effective veterinary anthrax vaccine and demonstrated it publicly at Pouilly-le-Fort in May 1881. The first human anthrax vaccine became available in 1954. The current FDA-approved US vaccine, BioThrax, was formulated in the 1960s.
In August 2008, the US Department of Justice announced it believed Bruce Ivins, a senior biodefense researcher employed by the United States government, was responsible for the 2001 anthrax attacks. The letters, which contained the Ames strain of anthrax, were sent to news media offices and two US senators, infecting 22 people and killing five.
Anthrax spores can survive for decades or even centuries in harsh conditions. Disturbed grave sites of infected animals have caused infection after 70 years. Russian researchers estimate Arctic permafrost contains around 1.5 million anthrax-infected reindeer carcasses, with spores capable of surviving up to 105 years.