Key to the species of genus Leptospira. I. Parasitic. Pathogenic for man and/or other animals. Requires serum for growth. Di- vided into numerous distinct serological types. 1. Leptospira iderohaemorrhagiae and presum- ably other species. II. Saprophytic. Grows in simple media. This species has not been further differentiated. 2. Leptospira biflexa and presumably other species. 1. Leptospira icterohaemorrhagiae (Inada and Ido, 1916) Noguchi, 1917. (Spiro- chaefa icterohaemorrhagica japonica Inada and Ido, Tokyo Ijishinshi, 1915, No. 1908; Spirochaeta ictero-haemorrhagiae japonica Inada and Ido, ibid., No. 1926; Spirochaeta ictero-haemorrhagiae Inada and Ido, Tokyo Ijishinshi, 1916, No. 1964; also see Inada, Ido, Hoki, Kaneko and Ito, Jour. Exp. Med., ^3, 1916, 377; Noguchi, Jour. Exp. Med., 25, 1917, 755.) ic.te.ro.hae.mor.rha'gi.ae. Gr. noun icterus jaundice; Gr. noun haemorrhagia hemorrhage; M.L. noun icterohaemorrhagia hemorrhagic jaundice; M.L. gen. noun icterohaemorrhagiae of hemorrhagic jaundice. Cells measure 0.25 to 0.3 by 6.0 to 9.0 mi- crons; occasionally measure 20.0 to 25.0 microns in length. Spiral amplitude, 0.4 to 0.5 micron, regular, rigid; spiral depth, 0.3 micron, regular. One or more gentle waves occur throughout the entire length. When in liquid media, one or both ends may be semi- circularly hooked, while in semisolid media the organism appears serpentine, waved or bent. Very active flexibility. Axial filament does not extend beyond cell body; flagella are absent. Body stains reddish by Giemsa's stain. Cultured easily in a medium containing 10 per cent rabbit serum, 0.2 per cent agar and a slight amount of hemoglobin in salt or in Ringer's solution. Does not grow in surface colonies. Bile salts (10 per cent) : The cells are easily dissolved. Saponin (10 per cent) : The cells are com- pletely resistant. Temperature range, 25° to 37°C. Remains alive longer at 25°C. Pathogenic for guinea pigs, deer-mice, hamsters and meriones. Comments: In general these characteris- tics apply to the other parasitic serotypes, although minor variations may occur in morphology and growth; there are also dif- ferences in the clinical symptoms (e.g. pres- ence or absence of jaundice) of the diseases which they produce in man and other sus- ceptible animals. Source: Orginally isolated from cases of infectious jaundice (Weil's disease) in man. Habitat: Found in kidneys and urines of wild rats. No insect vector is known. Sur- vives possibly for weeks in water and in slime (in mines and sewers). 2. Leptospira biflexa (Wolbach and Binger, 1914) Noguchi, 1918. (Spirochaeta biflexa Wolbach and Binger, Jour. Med. Res., 30, 1914, 23; Noguchi, Jour. Exp. Med., 27, 1918, 585.) bi.fle'xa. L. adj. bis twice; L. part. adj. flexus bent; M.L. adj. biflexus twice-bent. Cells, 0.2 to 0.25 by 5.0 to 7.0 microns, with tapering ends. Spiral amplitude, 0.2 to 0.25 micron. There are 22 to 30 waves per cell. Pass through an L5 candle filter. Stains best with Giemsa's stain. Growth occurs in simple media without serum. Optimum temperature, 20°C. Non-pathogenic. Comment: Comprises a large variety of antigenic types not 3^et satisfactorily differ- entiated. Source: Isolated from tap water, ponds and pools. Habitat: Found in fresh water.
