Summary
Definition
History and exam
Key diagnostic factors
- high remittent fever
- headache
- myalgia
- conjunctival suffusion
- muscle tenderness
Other diagnostic factors
- chills or rigors
- abdominal pain
- nausea or vomiting
- diarrhea
- asthenia
- anorexia
- photophobia
- eye pain
- neck stiffness
- cough
- dyspnea
- chest pain
- hemoptysis
- oliguria or polyuria
- cardiac arrhythmias
- lymphadenopathy
- splenomegaly
- hepatomegaly
- jaundice
- lymphadenopathy
- mental status changes
- morbilliform rash
Risk factors
- contact (direct or indirect) with urine of infected animals
- residence in or travel to an endemic area
- residence in or travel to an area with recent flooding
- involvement in water or adventure sports
- substandard housing or inadequate access to basic sanitation
Diagnostic investigations
1st investigations to order
- CBC and differential
- urinalysis
- microscopic agglutination test (MAT)
- enzyme-linked immunosorbent assay (ELISA)
- polymerase chain reaction (PCR)
- darkfield examination
- blood culture
- cerebrospinal fluid (CSF) culture
- ECG
- chest x-ray
- LFTs
- conjugated bilirubin
- metabolic profile
- serum pancreatic enzymes
- CSF analysis
Investigations to consider
- urine culture
- abdominal ultrasound
- renal biopsy
- lung biopsy
- staining methods
- Indirect hemagglutination assay
- latex agglutination
- western blot
- quantitative PCR
- lateral flow assays
Emerging tests
- cytokines
Treatment algorithm
mild disease
moderate to severe disease
Contributors
Authors
Molly Erin Fleece, MD, FIDSA
Associate Professor
Division of Infectious Diseases
Department of Medicine
University of Alabama at Birmingham
Birmingham, AL
Disclosures
MEF declares that she has no competing interests.
Stefania Carmona, MD
Assistant Professor
Division of Infectious Diseases
Department of Medicine
University of Alabama at Birmingham
Birmingham, AL
Disclosures
SC has received a professional services fee as an author of the Merck Manual Professional Version and the Merck Manual Consumer Version - Arboviruses, Arenaviridae, and Filoviridae chapters.
Acknowledgements
Dr Molly Erin Fleece and Dr Stefania Carmona would like to gratefully acknowledge Dr John Fournier, Dr Albert I. Ko, and Dr Nilmarie Guzman, previous contributors to this topic.
Disclosures
AIK has been reimbursed for participation in the Research Advisory and Advocacy Committee for the Reckitt Global Hygiene Institute. JF and NG declare that they have no competing interests.
Peer reviewers
Carmen Isache, MD
Assistant Professor of Medicine
Infectious Disease Division
University of Florida College of Medicine
Jacksonville, FL
Disclosures
CI declares that she has no competing interests.
Andreas Jansen, MD, DTM
Scientific Officer
Robert Koch Institute
Department for Infectious Disease Epidemiology
Gastrointestinal Infections
Zoonoses and Tropical Infections Unit
Berlin
Germany
Disclosures
AJ declares that he has no competing interests.
Sean V. Shadomy, DVM, MPH
Epidemiologist
Bacterial Zoonoses Branch
DFBMD/NCZVED/CCID
Centers for Disease Control and Prevention
Atlanta, GA
Disclosures
SVS declares that he has no competing interests.
Peer reviewer acknowledgements
BMJ Best Practice topics are updated on a rolling basis in line with developments in evidence and guidance. The peer reviewers listed here have reviewed the content at least once during the history of the topic.
Disclosures
Peer reviewer affiliations and disclosures pertain to the time of the review.
References
Key articles
Vijayachari P, Sugunan AP, Shriram AN. Leptospirosis: an emerging global, public health problem. J Biosci. 2008 Nov;33(4):557-69. Abstract
Centers for Disease Control and Prevention. CDC Yellow Book 2026: health information for international travel. Section 4: travel-associated infections and diseases - leptospirosis. Apr 2025 [internet publication].Full text
World Health Organization. Human leptospirosis: guidance for diagnosis, surveillance and control. Geneva: World Health Organization; 2003.Full text
Centers for Disease Control and Prevention. Leptospirosis: clinical overview of leptospirosis. Feb 2026 [internet publication].Full text
Centers for Disease Control and Prevention: National Notifiable Diseases Surveillance System (NNDSS). Leptospirosis (Leptospira interrogans) 2013 case definition. Apr 2021 [internet publication].Full text
Reference articles
A full list of sources referenced in this topic is available to users with access to all of BMJ Best Practice.
Differentials
- Hantavirus cardiopulmonary syndrome
- Dengue fever
- Malaria
More DifferentialsGuidelines
- Leptospirosis: clinical overview of leptospirosis
- CDC Yellow Book 2026: health information for international travel - leptospirosis
More Guidelines
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