Apodemus mice as reservoirs of pathogenic Leptospira in Europe: evidence from published studies

Leptospirosis is a major zoonotic disease caused by Gram-negative spirochetes of the genus Leptospira. While most human infections remain asymptomatic, severe forms such as Weil’s disease and severe pulmonary haemorrhagic syndrome may occur, with mortality reaching 15%. Globally, leptospirosis is estimated to cause approximately 60,000 deaths annually. Wild rodents play a central role in the epidemiology of the pathogen, as Leptospira colonises the renal parenchyma of reservoir hosts and is chronically shed in urine, contaminating soil and water and facilitating transmission to susceptible hosts. This study synthesises published evidence on the occurrence of pathogenic Leptospira in European Apodemus populations. Several species, including Apodemus flavicollis, A. sylvaticus, and A. agrarius, have tested positive for pathogenic leptospires such as Leptospira interrogans, L. kirschneri, and L. borgpetersenii. Transmission occurs through direct or indirect contact with environments contaminated by infected urine, highlighting the importance of environmental persistence in the pathogen’s life cycle. Ecological characteristics of Apodemus populations may contribute to the maintenance of leptospires in natural ecosystems. Rodent behaviour and habitat use can sustain environmental contamination and create infection hotspots, increasing the likelihood of exposure for humans and other hosts, particularly in peri-urban landscapes. The available evidence therefore supports the role of Apodemus species as contributors to the environmental circulation of pathogenic Leptospira in Europe, with implications for zoonotic risk at the wildlife-human interface.