Leptospirosis bacterium survival studied

PARIS, May 5 (UPI) -- French scientists say they have discovered how the pathogen that causes leptospirosis survives in the environment.

Leptospirosis is a serious emerging disease that infects humans through contaminated water. The illness is prevalent in Southeast Asia and South America, with more than 500,000 severe cases every year and with up to 20 percent of them being fatal.

Rats and other mammals carry the disease-causing pathogen Leptospira interrogans in their kidneys. When they urinate, they contaminate surface water with the bacteria.

"This led us to see if the bacteria build a protective casing around themselves for protection," said Professor Mathieu Picardeau of the Pasteur Institute in Paris. Previously, scientists said they believed the bacteria were "planktonic" -- living freely in the water. But Picardeau and his team found L. interrogans can make biofilms, which could be one of the main factors controlling survival and disease transmission."

The research appears in the journal Microbiology.