NEW LEPTOSPIRAL SEROTYPE IN THE PYROGENES SEROGROUP.

THE pyrogenes serogroup of the genus Lepto8pira is presently composed of eight serotypes. Leptospira pyrogenes, the first serotype found, was recognized by Vervoort (1) in Indonesia. Cotter (2) detected illness among sugarcane cutters in North Queensland which later proved to be caused by L. zanoni=L. australis B of Lumley (3). L. abratmis, L. biggis, and L. hamptoniz were isolated in Malaya and characterized by Alexander and associates (4). Alexander and associates reported studies on L. alexi which had been isolated from a person with leptospirosis in Puerto Rico (5). L. robinsoni was isolated in North Queensland and reported by Alexander and Smith (6). Galton and coworkers (7) have studied a strain isolated in Manila and designated it provisionally as L. manilae. Leptospirosis among nutria was first reported by Anchezar and associates (8). They reported that L. icterohaemorrhagiae (L. bonariensis) occurred naturally among nutria in Argentina. Roth and associates (9) isolated six strains o-f L. paidjan from nutria in Louisiana. This report describes the identification of a single leptospiral strain, LSU 1551, isolated from the renal tissue of a nutria, Myocastor coyputs, captured in a lake on the campus of Louisiana State University, Baton Rouge. On antigenic analysis, the strain was found to be a subserotype of L. zanoni, strain Zanoni. This finding constitutes the first bacteriological evidence of a member of the pyrogenes serogroup in the United States. The designation L. zanoni myocastoris is proposed for the new strain, and the designation L. zanoni zanoni is proposed for the Zanoni strain.