Normally, such studies are based upon laboratory research that looks at an organism and how it works within the human body.

But Carla Pruzzo, Luigi Vezzulli and Rita Colwell of the University of Genoa studied an environmental bacteria and its interaction with the environment and found that method provided them with vast amounts of information about how the organism they studied -- Vibrio cholerae -- causes cholera.

They discovered that in the aquatic environment the bacteria interacts with chitin, a naturally-occurring compound found in the cell walls of fungi and in crustaceans and insects. The interaction was found to play a large part in determining how the organism survives, how it is spread and how it infects humans.

"This knowledge provides a new framework for the understanding of the role of the non-human environment in affecting the spread of environmental disease-causing bacteria, their evolutionary derivation and the way they infect humans to cause disease," Vezzulli said.

The study was recently published in the journal Environmental Microbiology.