Molecular Diagnosis of Leptospires in Urban Rodents: Zoonotic Implications for Human Populations in Daloa (Central-Western Côte d’Ivoire)

Abstract

Background: Leptospirosis is a neglected zoonotic disease of considerable public health importance, particularly in tropical regions where inadequate sanitation and rodent proliferation favour bacterial transmission. Urban rodents may act as reservoirs of Leptospira, contributing to environmental contamination and potential human exposure. However, information on the circulation of leptospires in urban rodent populations in Côte d’Ivoire, particularly in Daloa, remains limited. Molecular surveillance is therefore essential to improve understanding of their occurrence in urban environments and associated zoonotic risks. Aims: This study aimed to detect Leptospira using molecular methods in urban mice from Daloa and assess the potential risk to nearby human populations. Study Design:  A cross-sectional study was conducted. Place and Duration of Study: Mice were captured in Daloa from May to December 2024. Methodology: Mice were captured using baited Sherman traps at various urban sites in Daloa, including sewers, markets, and selected households. Following euthanasia, kidney samples were collected, stored at −80 °C, and subjected to DNA extraction using the phenol–chloroform method. The samples were analysed using two PCR assays targeting the 16S ribosomal RNA gene (rrs) for the detection of the genus Leptospira and the secY gene, which is specific to pathogenic Leptospira species. Results: Three mice captured in sewer systems tested positive for the genus Leptospira by molecular diagnosis. No samples from markets or households were positive, and no pathogenic species for humans were identified during the study. Conclusion: The detection of the Leptospira genus in urban mice captured in sewers in the city of Daloa highlights the circulation of leptospires in the urban environment and suggests a potential public health risk for nearby populations. These findings underscore the need to strengthen urban sanitation measures, epidemiological surveillance, and further research to characterise the Leptospira species and serovars circulating in Côte d’Ivoire.