Results of the investigation of soil for contamination with pathogenic leptospires.

In the natural focus of leptospirosis at the lake Nero (Yaroslav region, USSR) 630 samples of soil were investigated for the presence of leptospires. Seven cultures of leptospires were isolated from the soil; five of them were pathogenic (four belonged to the serogroup Grippotyphosa and one to the serogroup Hebdomadis) and two were saprophytic. Among the cultures of pathogenic leptospires isolated from the soil there was observed the same quantitative ratio of serogroups as among cultures obtained from rodents, which suggests that the leptospires circulate from mammals to soil and vice versa.