Leptospirosis, a zoonosis found throughout the world, is caused by a bacterium from the Leptospira Interrogans complex, which is to blame for about 500,000 severe human cases per year worldwide, specifically in Latin American and Southeast Asia. It also affects some 300 people per year in France. In 5 to 20% of the cases, leptospiroses causes kidney failure leading to death. It is also a veterinary problem. A century after American born Arthur M. Stimson discovered the germ, Mathieu Picardeau from the Spirochetes Biology Unit, Pasteur Institute, working with a team at the Oswaldo Cruz Foundation, Brazil, used random gene inactivation techniques, and identified a virulence gene essential to the bacterium, for the first time.
Called loa22, the bacterium encodes a protein in the outer bacterium membrane. "Our goal is to verify whether the protein can be used for diagnostic tests and for the development of more effective vaccines," said Mathieu Picardeau. Currently available vaccines only have limited efficiency. Today's diagnostic tests, which are based on serology, take several weeks. As symptomatological diagnosis of the disease is hard to establish, a quick test would be useful for the speedy implementation of an appropriate treatment.
