John J Halperin MD (

Dr. Halperin of Overlook Medical Center and Sidney Kimmel Medical College of Thomas Jefferson University has stock ownership in Merck, Abbott, Abbvie, and Johnson & Johnson.

John E Greenlee MD, editor. (Dr. Greenlee of the University of Utah School of Medicine has no relevant financial relationships to disclose.)
Originally released March 16, 1994; last updated April 28, 2020; expires April 28, 2023

This article includes discussion of leptospirosis, Weil disease, and Weil syndrome. The foregoing terms may include synonyms, similar disorders, variations in usage, and abbreviations.


Leptospirosis is a common and significantly underdiagnosed multisystem zoonotic infection, most often presenting with conjunctival suffusion and myalgias. Although usually self-limited, it can pose a serious threat to patients and a management challenge to clinicians. The author reviews the range of clinical manifestations of this frequently occurring infection, with particular emphasis on the uncommon but potentially serious forms of nervous system leptospirosis. Diagnostic and therapeutic strategies are reviewed in detail.

Key points


• Leptospirosis is a common zoonosis, resulting in 1,000,000 severe infections and 60,000 deaths worldwide annually.


• Leptospirosis is typically spread in warm weather months through contact with bodies of water contaminated with urine or feces of infected rodents or other animals.


• Common clinical manifestations include conjunctival suffusion, headache, and myalgias.


• The illness tends to be biphasic, with the immune response playing an important pathogenic role in the second phase.


• The causative organism is responsive to multiple antibiotics, including penicillins and tetracyclines.


• Multiorgan damage, and even death, occurs in severe cases.

Historical note and terminology

In 1886, Weil described a clinical syndrome that now bears his name. Twenty-one years later, the leptospirosis spirochete was first visualized in the kidney of a patient who had died during a yellow fever epidemic (Stimson 1907). In 1916, 2 different groups isolated leptospires from Japanese mine workers and from subjects in France suffering from German trench disease (Inada et al 1916; Uhlenhut and Fromme 1946).

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