Epidemiological evidence of anti-Leptospira antibodies in horses at a global level (years 2015 to 2025): a systematic review and meta-analysis.

Overview

• This study systematically reviewed and analyzed data from 2015 to 2025 to estimate the global presence of antibodies against Leptospira bacteria in horses.
• It evaluated the frequency of different Leptospira types, geographic distribution of infections, and clinical signs associated with infection in horses worldwide.

Introduction and Background

• Leptospirosis is a bacterial disease that can be transmitted from animals to humans (zoonotic).
• In horses, leptospirosis may cause notable clinical symptoms and long-term health problems.
• Detecting antibodies against Leptospira indicates exposure or infection.
• Understanding the prevalence and distribution of these antibodies helps in managing and preventing the disease.

Objective of the Study

• To determine the global pooled seroprevalence of anti-Leptospira antibodies in horses using the Microscopic Agglutination Test (MAT), which is a standard diagnostic method.
• To identify the most common Leptospira serogroups and serovars infecting horses.
• To map the geographic locations of epidemiological studies conducted worldwide from 2015 to 2025.
• To report the primary clinical signs and organ-related complications linked to leptospirosis in horses.

Methods

• Conducted a systematic literature search to identify cross-sectional epidemiological studies focused on horses between 2015 and 2025.
• Assessed the quality and risk of bias in the selected studies.
• Performed statistical heterogeneity tests to measure consistency among study results.
• Applied a random effects meta-analysis model to calculate pooled prevalence estimates, accommodating variability between studies.

Results

• Total of 35 relevant studies included in the meta-analysis.
• The global pooled seroprevalence of anti-Leptospira antibodies in horses was 47.2%, with confidence intervals ranging between 37.6% and 57.1%.
• Most frequent Leptospira serogroups detected:
  • Australis (20.0%)
  • Icterohaemorrhagiae (17.1%)
• Most reported serovars:
  • Bratislava (15.2%)
  • Icterohaemorrhagiae (12.1%)
• Geographic distribution of studies:
  • Majority of studies were from South America, followed by Europe and Asia.
  • Countries with the highest number of studies included Brazil, Chile, and the USA.
• Seroprevalence by continent:
  • North America: 71.0%
  • South America: 55.0%
  • Asia: 49.0%
  • Oceania: 34.0%
  • Europe: 27.0%
• Main clinical signs observed in horses infected with leptospirosis included recurrent uveitis (eye inflammation) and fever.
• Common organ-related manifestations involved reproductive system disorders and renal failure.

Conclusions

• The study reveals a high global seroprevalence of Leptospira exposure in horses, pointing to widespread risk.
• Results highlight the importance for veterinarians and animal health authorities to consider leptospirosis as a relevant equine health issue.
• Continuous monitoring, research, and updating of knowledge about leptospirosis in horses are essential for controlling this zoonotic disease.
• The data can help guide future prevention, diagnosis, and treatment efforts globally and locally.