Infestation of Oriental House Rat () with Chigger Mites Varies Along Environmental Gradients Across Five Provincial Regions of Southwest China

Chigger mites are the exclusive vector of scrub typhus. Based on field investigations of 91 survey sites in 5 provincial regions of Southwest China, this paper reported variations of chigger infestation on the oriental house rat () along various environmental gradients. A total of 149 chigger species were identified from 2919 in the 5 provincial regions, and (a major vector of scrub typhus in China) was the first dominant chigger species, followed by and . had a stable overall prevalence ( = 21.10%), mean abundance ( = 7.01), and mean intensity ( = 33.20) of chiggers with the same dominant mites in the whole Southwest China in comparison with a previous report in Yunnan Province, but chigger infestations on varied along different environmental gradients. in mountainous landscape had a higher infestation load of chiggers with higher species diversity than in flatland landscape. The infestation was higher at lower altitudes and latitudes. A high intensity of vegetation coverage was associated with high infestations. The results reflect the environmental heterogeneity of chiggers on the same host species. Warm climate and high relative humidity are beneficial to chigger infestation on .