 Later, in 1951, when the necessary technology became available to perform agglutination tests and cross-reference agglutination tests, they found that it was a species of the genus "Leptospira".At the time, the pathogen was thought to be called "Leptospira Autumnalis", but upon further study of the whole-genome, it was later reclassified as a serovar of "Leptospira noguchii".This Leptospirosis became known as “Fort Bragg Fever.”

The Bonito strain of "L. noguchii" was isolated from a 34-year-old man in Brazil that was suffering from Leptospirosis.