Isolation of Icterohaemorrhagiae from Microtus monte belli trapped at the Nagaoka area, Niigata Prefecture in Japan.

Three strains of leptospira were isolated from field rodents on the occasion of scrub typhus survey on the Nagaoka, Kurojo, Kamikawanishi area, Niigata Prefecture in September 1961. Out of 10 Microtus montebelli 3 strains of leptospira by means of heart puncture in febrile stage from guinea pigs. They were identified as icterohaemorrhagiae by cross-agglutination-lysis and a cross absorption tests. It was the first report of icterohaemorrhagiae in Microtus montebelli in Japan.