Molecular epidemiology of Leptospira noguchii reveals important insights into a One Health context.

Leptospirosis presents a complex and dynamic epidemiology. Bovine leptospirosis has been described as a major infectious disease impairing reproductive efficiency. Although infections by Leptospira interrogans, L. santarosai and L. borgpetersenii are frequently reported in cattle, the presence of L. noguchii in these animals should not be neglected. In this study, we describe serological (MAT) and molecular characterization (rrs and secY gene sequencing, multilocus sequence typing [MLST] and pulsed-field gel electrophoresis [PFGE]) of eight L. noguchii strains obtained from slaughtered cows. Intraspecific genetic diversity was evaluated, and haplotype networks were constructed based on hosts and geographical localizations. Strains were characterized as belonging to serogroups Australis, Autumnalis and Panama, and molecular characterization showed a high heterogeneity of these strains. Ten different STs were found (including nine new STs and 39 novel alleles) as well as nine different pulsotypes. Two clonal complexes were found. Phylogenetic trees based on secY locus and concatenated MLST loci showed two main clusters, with sequences from the present study included in the first. In general, there was no relationship between the geographical origin and the secY phylogenetic clusters, as well as between secY phylogenetic clusters and serogroups. Molecular diversity indexes confirmed a high variability (H > 0.8). This high intraspecific variation observed may be related to differences in virulence, pathogenicity and antigenicity or even adaptability of the strains. In addition, haplotype networks clearly demonstrated the circulation of genotypes between humans and animals, confirming the zoonotic potential. The present study provides relevant data for the study of leptospirosis in the One Health context, where human, animal and environmental health is closely connected.

Presence of leptospires on genital tract of mares with reproductive problems.

Leptospirosis is a zoonotic disease of global importance, and has a worldwide distribution. Equine leptospirosis is commonly manifested by recurrent uveitis, reproductive disorders, as abortions, embryonic absorption, stillbirth and the birth of weak foals. The aim of this study was to verify the presence of Leptospira sp or its DNA in genital tract of mares with reproductive problems. A total of 38 mares with reproductive problems were studied. All the mares were sampled for blood (for serology), urine (for culturing and qPCR), vaginal fluid-VF and endometrial biopsy-EB (for culturing, qPCR and indirect immunofluorescence). PCRs products were sequenced for secY gene. Seventeen (44.7%) serum samples were reactive, predominantly against serogroups Australis (76.4%) and Pomona (23.6%). No positive culture was obtained, but DNA was detected by qPCR on urine samples (26.3%), VF (44.7%) and EB (18.4%) collected 2 months or longer following diagnosis of early fetal death and endometritis. Leptospira cell aggregations were visible by indirect immunofluorescence on 57.1% (4/7) EBs and 17.6% (3/17) VFs. A total of 18 amplicons showed interpretable sequences. Out of those 18 amplicons, 15 presented 100% of identity with the species L. interrogans (sv Bratislava and Pomona), while three were L. borgpertersenii. This study suggests the presence of leptospires in the uterus of mares with reproductive problems. Moreover, serology was shown not to be indicated for the diagnosis of presumptive Leptospira infection in early gestation. The most common agent of the genital infection in those mares was L. interrogans, most probably sg Australis.