Molecular Detection and Genotyping of Pathogenic Leptospira in Small Mammals from Southern Vietnam.

Leptospirosis is a major zoonosis, yet genetic data on Leptospira strains in animal reservoirs in Southern Vietnam are limited. This study aimed to detect and genotype pathogenic Leptospira in synanthropic small mammals. From 2016 to 2020, 856 animals were captured in three regions. Kidneys were screened by qPCR targeting pathogenic Leptospira 16S rRNA, and positive samples were genotyped via secY gene sequencing. The overall prevalence was 7.8%. Rattus norvegicus was the primary host (12.4% infected). Leptospira interrogans predominated (77.6%), followed by L. borgpetersenii (22.4%). Infection risk was significantly associated with the following factors: larger host body size (increased body mass and hindfoot length); capture in Ho Chi Minh City; and the rainy season. The study confirms the stable circulation of highly virulent L. interrogans in urban R. norvegicus populations. The identified risk factors provide a basis for targeted interventions to mitigate human health risks.