The Japanese group also experimented with the first leptospiral immunisation studies in guinea pigs. They demonstrated that by injecting the infected guinea pigs with sera from convalescent humans or goats, passive immunity could be provided to the guinea pigs. In 1917, the Japanese group discovered rats as the carriers of leptospirosis. Unaware of the Japanese groups work, two German groups independently and almost simultaneously published their first demonstration of transmitting leptospiral infection in guinea pigs in October 1915. They named the organism Spirochaeta nodosa and Spirochaeta Icterogenes respectively.Leptospirosis was subsequently recognised as a disease of all mammalian species. In 1933, Dutch workers reported the isolation of Leptospira canicola which specifically infects dogs. In 1940, the strain that specifically infects cattle was first reported in Russia. In 1942, soldiers at Fort Bragg, North Carolina, were recorded to have an infectious disease which caused a rash over their shinbones. This disease was later known to be caused by leptospirosis. By the 1950s, the number of serovars that infected various mammals had expanded significantly. In the 1980s, leptospirosis was recognised as a veterinary disease of major economic importance.In 1982, there were about 200 serovars of Leptospira available for classification. The International Committee on Systematic Bacteriologys subcommittee on taxonomy of Leptospira proposed classifying these serovars into two big groups: L. interrogans containing pathogenic serovars and L. biflexa containing saprophytic serovars. In 1979, the leptospiral family of Leptospiraceae was proposed. In the same year, Leptospira illini was reclassified as the new genus Leptonema.
The version of record as reviewed is: 
Siang Ching Raymond Chieng;  et al. (21 June 2022). "Leptospirosis". WikiJournal of Medicine. 9 (1): 2. doi:10.15347/WJM/2022.002. ISSN 2002-4436. Wikidata Q100400590. External links
"Leptospirosis". U.S. Disease Control and Prevention Center. 21 November 2018. "Leptospira". NCBI Taxonomy Browser. 171.