The strain Naam was isolated by Wolf in 1936, from a fatal case of leptospirosis in a labourer in Medan, Sumatra, Indonesia (Walch-Sorgdrager et al., 1940).
The strain was later studied serologically and appears in Wolff and Broom's list (1954) as a separate serovar named naam. The separate serological status of the strain was confirmed by factor analysis (Kmety, 1967).