Equine Genital Leptospirosis (EGL) in mares with poor reproductive performance

Taken from the article and to give the abstract a little background:
At the time of sampling, despite the history of poor reproductive performance, six mares did not present any reproductive issues. Out of the 35 presenting reproductive failures, 20 were subfertile due to repeat breeding, 14 showed clinical signs of endometritis, and one had recently experienced a stillbirth….
The most important outcome of the study was the high rate of mares with poor reproductive performance positive for Leptospira spp., particularly on genital sites, confirming the diagnosis of Equine Genital Leptospirosis (EGL). Noteworthy that, besides the reproductive failure, none of the animals had any of the classic clinical signs of leptospirosis in horses, such as ocular, pulmonary alterations, or hepatorenal disease. .
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Diagnosis of Equine Genital Leptospirosis (EGL) in mares with poor reproductive performance

Vet Microbiol. 2026 Feb 3:315:110924. doi: 10.1016/j.vetmic.2026.110924. Online ahead of print.
Authors
Daiany Motta 1 , Luiza Aymée 2 , Isabel Roussouliéres 1 , Maria Isabel Nogueira Di Azevedo 3 , Júlio Cesar Ferraz Jacob 4 , Walter Lilenbaum 5
Affiliations

1 Laboratory of Veterinary Bacteriology, Biomedical Institute, Federal Fluminense University, Niteroi, Rio de Janeiro, Brazil.
2 Laboratory of Veterinary Bacteriology, Biomedical Institute, Federal Fluminense University, Niteroi, Rio de Janeiro, Brazil; Department of Microbiology, Immunology and Parasitology, Faculty of Medical Sciences, Rio de Janeiro State University, Rio de Janeiro, Brazil.
3 Department of Medical Microbiology, Paulo de Góes Institute of Microbiology, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
4 Department of Animal Reproduction, Federal Rural University of Rio de Janeiro, Seropédica, Rio de Janeiro, Brazil.
5 Laboratory of Veterinary Bacteriology, Biomedical Institute, Federal Fluminense University, Niteroi, Rio de Janeiro, Brazil. Electronic address: wlilenbaum@id.uff.br.

PMID: 41650487
DOI: 10.1016/j.vetmic.2026.110924

Abstract

Leptospirosis is a zoonotic disease caused by spirochetes of the genus Leptospira. Equine genital leptospirosis (EGL) has been described as a chronic and silent syndrome, presenting reproductive alterations such as abortion, stillbirth, placentitis, embryonic loss, repeat breeding syndrome, and subfertility. This study aimed to investigate the genital Leptospira infection in naturally infected mares with poor reproductive performance, as well as to genetically characterize the agents. A total of 41 mares with a history of poor reproductive performance were selected. Sera were collected for serology by Microscopic Agglutination Test (MAT), while urine, uterine mucus, and uterine fragment samples were collected for a lipL32-PCR screening. Samples positive at lipL32-PCR were submitted to secY gene sequencing. Considering MAT, 17/41 mares were seroreactive (41.5 %). The most frequent serogroup was Australis, detected in 13 animals (76.5 % of the reactive). Out of the 41 mares, 25 (61.0 %) were positive in lipL32-PCR and, of these, 21 (84.0 %) showed positive in at least one genital sample. Regarding secY nested-PCR, only six samples, all from the uterine fragment, were amplified, and all were characterized as Leptospira interrogans with ≥ 99 % of similarity with isolates of serovar Bratislava, from the Australis serogroup. Our results confirmed the diagnosis of EGL and highlighted the high detection rate of Leptospira DNA in genital samples of mares with poor reproductive performance.

Keywords: Horses; Leptospira; PCR; Reproduction; Uterus; secY.

Copyright © 2026. Published by Elsevier B.V.

• This topic was modified 3 weeks ago by Robert Oglesby DVM.