MORE than 70 years have passed since Weil first described several cases of leptospirosis in humans although he had no knowledge of the etiologic agent. In 1905, Stimson, in New Orleans, first observed leptospires in kidney sections from a patient believed to have died of yellow fever. A few years later (1915) pathogenic leptospires were isolated first from patients with Weil's disease in Japan by Inada et al. and independently in Germany by Uhlenhuth and Fromme in the same year. About the same time the Japanese workers found that the rat (Rattus norvegicus) is a carrier of Leptospira icterohemorrhagiae. Since this early work, extensive investigations have shown that leptospirosis occurs in humans and animals in all parts of the world and is not a single disease but a group of diseases caused by a variety of leptospiral serotypes. Possible explanations for the wide distribution of these diseases may be (1) that they are insidious infections which have appeared gradually and become established almost unnoticed, or (2) that they have been present for many years and remained largely undetected because of the variable masking symptoms and the problems associated with laboratory diagnosis. Although considerable attention has been directed toward studies of leptospiral infections by European and Asian investigators since the early 1930's much of our knowledge regarding the epidemiology, public health importance and distribution of these diseases in the United States has been gained only during the past decade.
The epidemiology of the leptospiroses has been shown to follow a characteristic pattern based, in part, upon the fact that they are zoonoses, diseases transmitted from animal to animal and from animal to human.
- Copyright © 1958 by the American Academy of Pediatrics