Small mammals and associated infections in China: a systematic review and spatial modelling analysis.

Background: As natural reservoirs of diverse pathogens, small mammals are considered a key interface for guarding public health due to their wide geographic distribution, high density and frequent interaction with humans.

Methods: All formally recorded natural occurrences of small mammals (Order: Rodentia, Eulipotyphla, Lagomorpha, and Scandentia) and their associated microbial infections in China were searched in the English and Chinese literature spanning from 1950 to 2021 and geolocated. Machine learning models were applied to determine ecological drivers for the distributions of 45 major small mammal species and two common rodent-borne diseases (RBDs), and model-predicted potential risk locations were mapped.

Findings: A total of 364 small mammal species collectively carrying 155 small mammal-associated microbes (SMAMs) combined with 215,791 human cases of eight RBDs were reported in 2484 counties in China. Murid rodents (Family: Muridae) including the brown rat (), the house mouse (), and the striped field mouse () are the most widespread species, while harbored the highest variety of SMAMs (75 species), followed by the tanezumi rat () (68 species). The top three SMAMs that infest the highest variety of small mammal species are (58 small mammal species), (36 species), and (33 species). The 45 major species of small mammals were grouped into six ecological clusters based on their ecological niche, mainly driven by annual mean temperature, temperature seasonality, total precipitation, and elevation. Model-predicted presence areas for the 45 major small mammal species and two RBDs were 1-499% larger in geographic size than observed.

Interpretation: The extensive intersection between small mammals and microbes with pathogenic potential in humans poses imminent threats to public health. Active field surveillance should be prioritized for potential high-risk areas identified in this study to prevent zoonotic transmission of SMAMs.

Funding: National Key Research and Development Program of China; Natural Science Foundation of China; The U.S. Centers for Disease Control and Prevention.