Leptospira qPCR Positivity in Terrestrial Micromammals and Dogs in Saen Thong (Tha Wang Pha District), Ecological Analysis in Micromammals, and Leptospira Diversity Across Animal Hosts in Thailand

Human leptospirosis is a disease of public health importance in Thailand, but the animal species involved in the transmission cycle have not been fully uncovered. This study investigated Leptospira in dogs and terrestrial micromammals in rural Saen Thong, Tha Wang Pha district, Thailand. Sera (n = 95) from 53 clinically healthy dogs and kidneys from 399 micromammals were tested for Leptospiral DNA by qPCR, and Leptospira-positive samples were amplified for sequencing. In micromammals, we also investigated associations between Leptospira positivity and sex, body mass and landscape type. Molecular testing detected Leptospira DNA in 13.2% (7/53) of clinically healthy dogs and 10.0% (40/399) of micromammals, with 12 species testing positive, including Bandicota indica, Berylmys berdmorei, Berylmys bowersi, Mus cervicolor, Mus cookii, and Hylomys suillus. In micromammals, three pathogenic Leptospira species were identified: L. interrogans, L. weilii, and L. borgpetersenii. To our knowledge, this is the first detection of L. weilii in Thai rodents. Leptospira positivity was detected across all different landscapes, and was not significantly associated with any of the tested variables. The detection of Leptospira DNA in clinically healthy dogs warrants further investigation. Integrated One Health surveillance could help uncover Leptospira diversity and transmission pathways.