Ecological niche and rickettsial risk mapping of Dermacentor nuttalli in Inner Mongolia, China

Dermacentor nuttalli is the most prevalent and impactful tick species in Inner Mongolia, and serves as an important vector for a variety of pathogenic microorganisms.

In this study, an optimized ecological niche model was used to analyze the distribution of suitable habitats for D. nuttalli. Combined with pathogen detection data from the salivary glands of 8512 adult ticks collected across Inner Mongolia from 2015 to 2025 and relevant literature, we identified 20 tick-associated pathogens. Additionally, we integrated multiple datasets including environmental and ecological factors, vector distribution, host density and transportation-trade indicators to conduct a comprehensive risk assessment of Rickettsiae transmission.

Currently, suitable habitats for D. nuttalli cover 56.0% of the total area of Inner Mongolia. The moderate and high suitability areas in Xilingol, Ulanqab and Erdos all account for over 50%. Precipitation of the wettest month (Bio 13) and mean diurnal range (Bio 2) were confirmed as the key driving factors. Under the SSP2-4.5 future climate scenario, the suitable habitat range will continue to expand, with its distribution centroid shifting approximately 134 km southwestward by 2100. Among the detected pathogens, spotted fever group Rickettsiae had the highest positive rate and dominated the pathogen community, followed by Anaplasmataceae and Borreliaceae, which were also frequently reported. Southern Xilingol, northern Ulanqab and northwestern Chifeng were identified as high-risk regions for Rickettsiae transmission.

This study provides valuable references for the targeted surveillance and prevention of tick-borne rickettsiosis.