Anthrax is found all over the world. It contaminates the ground when an affected animal dies. It spreads when grazing animals pick it up from contaminated dirt or through contaminated food sources such as bone meal that may have been made from contaminated carcasses. There appears to be an increase in the cases of anthrax among grazing animals during droughts, when they tend to graze closer to the ground and consume more dirt with the grass.
Anthrax may also spread when carnivorous animals, such as vultures or even insects, feed on affected herbivores. The bacteria are then transferred to other areas by the host and contaminate the ground when that animal dies. As the animal decays, the bacteria are exposed to oxygen and turn back into the spores that contaminate the soil. The anthrax spores have a very tough outer casing and can remain viable in the ground for decades.
Many diagnostic laboratories around the world have anthrax samples for use in research and for the identification of anthrax. Anthrax can be grown in laboratories from these existing spores. In the wrong hands, these spores can be grown, dried and milled for use in biological weapons.