Study of Leptospira spp. in rodents and water sources: implications for public health in rural environments from Buenos Aires province, Argentina.

Leptospirosis, a zoonotic disease caused by Leptospira spp. poses significant public health and economic challenges. Its transmission is favored in interface environments where wild and synanthropic rodents acting as maintenance hosts contaminate surroundings with urine. Additionally, water sources can harbor leptospires, serving as an infection risk for humans and animals. This study aimed to investigate the presence of Leptospira spp. in surface and underground water resources, detect leptospiras in wild and synanthropic rodents, and identify/genotype isolation in rural environments from Tandil county, Argentina. Thirty-five water samples and kidney samples from 30 rodents were collected. Leptospira spp. Isolation was attempted via culture in a selective EMJH-STAFF medium with observations made through fluorescence microscopy. Growth of leptospires was observed in one rodent kidney tissue sample. The presence of a pathogenic Leptospira strain was confirmed by 16S rRNA PCR and subsequently genotyped by MLST. Notably, this represents the first isolation of Leptospira interrogans serogroup Canicola allelic profile ST3 from Akodon Azarae in Argentina, making a significant epidemiological finding for the region. While Leptospira spp. was not detected in the analyzed water samples, the isolation of L. interrogans highlights the role of wild rodents as persistent reservoirs in the rural-urban interface. This finding suggests that the transmission dynamics may involve a more complex network of wild reservoirs, highlighting the potential public health risk to local inhabitants and domestic animals.