Scientists in the United States say they have discovered how anthrax turns into a deadly killer.
Anthrax spores spread quickly
They have identified the genes and proteins that enable anthrax particles or spores to reproduce.
These spores are highly infectious and can spread quickly once they enter animals or humans.
The findings, published in the Journal of Bacteriology, could lead to new vaccines and treatments to fight the deadly bacterium.
Anthrax spores can survive drought, bitter cold and other harsh conditions for decades.
Once inside an animal or human, they reproduce almost instantly to infect and kill.
The US Government has funded a major study to find out how these spores reproduce, in the hope that this information could lead to new weapons against anthrax.
Scientists from the University of Michigan, the Institute for Genomic Research and The Scripps Research Institute have all been involved in the work.
They have found that anthrax spore formation is an unusually complex and intricate process.
Up to one-third of all of the genes in the Bacillus anthraces genome - the bacterium that causes anthrax - are involved in spore production.
They have found that these genes are expressed or start working in five different stages over a five-hour period.
Each mature anthrax spore contains about 750 individual proteins.
"Until recently, we only knew how the anthrax spore was made on a microscopic level," said Dr Nicholas Bergman of the University of Michigan.
"Now, we have a much clearer view of how the spore is assembled and exactly what it is made of."
The scientists believe that knowing how anthrax reproduces could lead to new treatments to fight it.
"The spore allows the anthrax bacterium to survive conditions that would kill most other living things," said Dr Philip Hanna of the University of Michigan.
"The most surprising result of this study is the degree of dedication this organism devotes to making its spore," he said.
"It may require one-third of the entire genome. This shows how important the spore is to this organism's life-cycle."
"The spore is the infectious agent of anthrax," said Brendan Thomason, one of those involved in the study.
"In order to understand how the bacterium causes disease and discover new methods for anthrax treatment and prevention, scientists need a more thorough understanding of the intricacies of the spore."