Molecular typing and seroepidemiology of pathogenic Leptospira spp. of domestic animals in Gilan province, northern Iran during 2021-2023.

Background: Leptospira, a pathogenic bacterial organism, causes human leptospirosis when it infects mammals. There are different serovars of Leptospira, each of which is adapted to a specific animal host. Adaptation occurs dynamically in different hosts and changes the distribution and clinical manifestations of serovars. Variable-number tandem repeats (VNTRs) have been used to identify Leptospira interrogans strains.

Aims: The purpose of this study was to conduct seroepidemiology and molecular typing of pathogenic Leptospira isolated from domestic animals in Gilan province.

Methods: A total number of 250 urine and blood samples were collected from domestic animals (horse, bovine, and sheep). Urine samples were cultured in EMJH medium. Using the microscopic agglutination test (MAT) and the Multilocus VNTR Analysis (MLVA) methods, unknown samples were analyzed to determine Leptospira serovars.

Results: Based on our data, Leptospira Autumnalis was mainly found in horses and dominated at 50%, followed by Leptospira Canicola at 29.16%. MAT results showed that among 87 animals with the seropositive, the horses showed the highest level of contamination at 40%, and this difference was not significant (P=0.152).

Conclusion: According to our data, Leptospira Autumnalis was mainly found in horses, and the bacteria were shed in urine, suggesting that horses could transmit leptospirosis. The results of this study confirm that MLVA can replace time-consuming methods such as MAT because it is a simple and fast technique.