Mite Infestation on Rattus tanezum Rats in Southwest China Concerning Risk Models

Ru-Jin Liu ¹ Xian-Guo Guo ^1,2* Pei-Ying Peng ³ Yan Lv ¹ Peng-wu Yin ¹ Wenyu Song ¹ Rong Xiang ¹ Yan-Ling Chen ¹ Bei Li ¹ Dao-Chao Jin ⁴

• ¹ Institute of Pathogens and Vectors, Yunnan Provincial Key Laboratory for Zoonosis Control and Prevention, Dali University, Dali, China
• ² Xian-Guo Guo, Dali, China
• ³ Qujing Medical College, Qujing, Yunnan Province, China
• ⁴ Institute of Entomology, Guizhou University, Guiyang, Guizhou Province, China

Abstract: Objective: The Asian house rat (Rattus tanezumi) is an important infectious source and reservoir host for many zoonotic diseases, and its associated mites (chigger mites and gamasid mites) can serve as vectors of these diseases. The present study aims to elucidate the infestation and related ecology of the mites on the body surface of R. tanezumi in southwest China, and delve into the concerning risk models. Methods: The field surveys and taxonomic identification of the mites were conducted in five provincial regions of southwest China between 2001 and 2022. The constituent ratio (Cr), prevalence (Pm), mean abundance (MA) and mean intensity (MI) were calculated to reflect the mite infestation status. The species richness index (Mf), Shannon–Wiener diversity index (H´), Pielou evenness index (E) and Simpson dominance index (D) were used in the statistics of mite communities. The multiple logistic regression model was used to analyze the potential risk factors of mite infestation. The "corrplot" R software (version 4.3.1) package was used to analyze interspecific relationships among some mite species. Results: A total of 75023 mites collected from 3114 rats (R. tanezumi) were identified comprising 12 families, 46 genera and 252 species, including 173 chigger mite species and 79 gamasid mite species. The species richness and community diversity of chigger mites were higher than those of gamasid mites, but infestation indexes of gamasid mites on the rat were higher than those of chigger mites. Several vector mite species co-existed on R. tanezumi, among which Laelaps nuttalli, L. echidninus and Leptotrombidium deliense were three dominant mite species with high infestation indexes. The analysis of multiple logistic regression showed that the mite infestation was influenced by a series of environmental factors and host factors (potential risk factors), and the temperature and relative humidity were the most important risk factors. The influence of potential risk factors on the infestation of a single mite group alone (chigger mites or gamasid mites) was different from the co-infestation of two mite groups together.