Leptospirosis

钩端螺旋体病

Evidence-backed information EN 5/7 applicable sections · ZH 5/7 applicable sections Updated Oct 23, 2026

Leptospirosis is a globally distributed zoonotic bacterial disease caused by pathogenic Leptospira spirochaetes, affecting humans, dogs, and horses ^[1]^[2]^[3]^[4]. It is recognized as an emerging infection linked to recreational exposure and natural disasters, with substantial morbidity and mortality concentrated in resource-poor populations ^[4]^[5]. Annual global human burden is estimated at roughly one million cases and 60,000 deaths ^[1].

Read the full clinical and epidemiological profile 6

Definition

Leptospirosis is a zoonotic bacterial infection prevalent on all continents, caused by pathogenic spirochaetes of the genus Leptospira ^[1]. It is transmitted through animal-associated pathways and has been classified as an emerging disease owing to outbreak clusters from recreational activities and disasters ^[4].

Clinical features

Infection may be asymptomatic, but symptomatic presentations range from mild to severe illness ^[1]. Severe human disease is marked by jaundice and/or multi-organ dysfunction with possible fatal outcome ^[1]. In horses, clinical expression has principally involved uveitis with recurrent ocular sequelae, sporadic hepatic or renal involvement, and increasingly reported abortion, stillbirth, and neonatal disease ^[3].

Epidemiology

Human leptospirosis occurs worldwide with an estimated one million annual cases and about 60,000 deaths ^[1]^[5]. The disease remains prevalent in dogs across urban and rural settings, including small-breed urban dogs, puppies from 11 weeks, geriatric dogs, and inadequately vaccinated animals ^[2]. Equine diagnostic reports of abortion and neonatal infection have risen, likely reflecting improved diagnostics rather than greater prevalence ^[3].

Transmission

Leptospirosis arises through zoonotic exposure to Leptospira, with human infection associated with animal urine contamination and notable clusters from recreational activities and natural disasters ^[1]^[4]. Preventive exposure control relies on behavioural modification and personal protective measures ^[1].

Prevention

Few countries have licensed human vaccines, and those available cover only rodent-associated serogroups, limiting broad protection ^[1]. Primary prevention emphasizes behavioural changes and personal protective measures to reduce exposure, while prophylactic antibiotic efficacy lacks confirmation in clinical trials ^[1]. Veterinarians contribute to public health by advising on risk factors and control measures ^[4].

References

1 Rajapakse S et al. Leptospirosis. Nat Rev Dis Primers. 2025 May 2. PMID: 40316520. doi: 10.1038/s41572-025-00614-5. PubMed: https://pubmed.ncbi.nlm.nih.gov/40316520/
2 Sykes JE et al. Updated ACVIM consensus statement on leptospirosis in dogs. J Vet Intern Med. 2023 Nov-Dec. PMID: 37861061. doi: 10.1111/jvim.16903. PubMed: https://pubmed.ncbi.nlm.nih.gov/37861061/
3 Bernard WV et al. Leptospirosis. Vet Clin North Am Equine Pract. 1993 Aug. PMID: 8358656. doi: 10.1016/s0749-0739(17)30410-8. PubMed: https://pubmed.ncbi.nlm.nih.gov/8358656/
4 Guerra MA et al. Leptospirosis. J Am Vet Med Assoc. 2009 Feb 15. PMID: 19222355. doi: 10.2460/javma.234.4.472. PubMed: https://pubmed.ncbi.nlm.nih.gov/19222355/
5 Rajapakse S et al. Leptospirosis: clinical aspects. Clin Med (Lond). 2022 Jan. PMID: 35078790. doi: 10.7861/clinmed.2021-0784. PubMed: https://pubmed.ncbi.nlm.nih.gov/35078790/