Preliminary investigation about zoonotic interfaces : prevalence of Salmonella spp. in bats, rodents and dogs in Nan Province, Thailand

Abstract

The BCOMING project started as a post-pandemic initiative that aims to understand how biodiversity impacts the spread of zoonotic diseases and how to limit their emergence by means of biodiversity conservation strategies and disease surveillance. The COVID-19 pandemic highlighted how vulnerable our society is to Emerging Infectious Diseases (EIDs) from wildlife. Human impacts on these ecosystems intensify risks due to two main factors: increased interactions between wildlife, humans, and domestic animals due to human activities, and biodiversity loss which disrupts wildlife interactions and elevates pathogen circulation in remaining animal populations. This work takes part in the BCOMING project, investigating the circulation patterns and prevalence of Salmonella spp. across a wildlife and domestic interface in Nan Province (Thailand), especially in bats, small mammals, and dogs. This bacterial genus is a good candidate for zoonotic perspective as it can infect a wide range of animals, including humans, livestock, pets, and wildlife. It is also known to be one of the most important foodborne pathogens and a widespread global public health threat. This study integrates fieldwork and laboratory analysis to elucidate the dynamics of disease transmission from wildlife to peri-urban and domestic animals potentially exposing humans. We sampled bats, rodents and dogs using rectal swabs at the human-animal interface ranging from December 2021 to December 2022. DNA was extracted and tested using quantitative Polymerase Chain Reaction (qPCR) to detect the presence of Salmonella spp., with particular attention to its prevalence in different species, ages, and sexes. Results have shown the presence of Salmonella spp. in 9 out of 45 bats (20%), 5 out of 23 owned dogs (21,7%) and 0 out of 48 rodents. Initial findings indicate variable rates of Salmonella presence, suggesting interaction networks between species such as Rhinolophus pusillus (n=1), Hipposideros armiger (n=3), Scotophilus heathii (n=5) for bats. Most of the positive samples have been collected in the dry season, potentially indicating seasonal implications. The project underscores the critical role of ecological and biological factors in the circulation of pathogens at human-animal interfaces and calls for an integrated approach to managing zoonotic risks in hotspot areas.