Leptospirosis is presumed to be the most geographically widespread zoonotic disease in the world, and regarded as a re-emerging infectious disease that effects human populations on a global scale. A severe pulmonary form of leptospirosis (SPFL) is appearing and results in high mortality among patients. The first successful isolation of leptospires from patients suffering from SPFL occurred in 1998 at the National Leptospirosis Reference Laboratory in Brazil. The research program to be undertaken during the period of training is based on the study of these isolates obtained from patients suffering from SPFL. More specifically, 1) the tools of proteomics will be used to identify and characterize proteins of the outer membrane of SPFL isolates and 2) characterization of an animal model of disease (guinea pig) which will be used to 3) identify leptospiral proteins expressed during infection. ? ?