Anthrax is a bacterium often found in soil, according to Jerrold Leikin, a doctor who co-edited a book on “toxico-terrorism”. Its spores are one to five microns across – small enough to get into human lungs. The initial symptoms of infection look like flu, but quickly progress to sepsis, hemorrhagic meningitis and death. Once it progresses to those last stages, the fatality rate is around 95%.