Mapping the risk distribution of <i>Borrelia burgdorferi</i> sensu lato in China from 1986 to 2020: a geospatial modelling analysis

Abstract

Lyme borreliosis, recognized as one of the most important tick-borne diseases worldwide, has been increasing in incidence and spatial extent. Currently, there are few geographic studies about the distribution of Lyme borreliosis risk across China. Here we established a nationwide database that involved <i>Borrelia burgdorferi</i> sensu lato (<i>B. burgdorferi</i>) detected in humans, vectors, and animals in China. The eco-environmental factors that shaped the spatial pattern of <i>B. burgdorferi</i> were identified by using a two-stage boosted regression tree model and the model-predicted risks were mapped. During 1986-2020, a total of 2,584 human confirmed cases were reported in 25 provinces. <i>Borrelia burgdorferi</i> was detected from 35 tick species with the highest positive rates in <i>Ixodes granulatus</i>, <i>Hyalomma asiaticum</i>, <i>Ixodes persulcatus</i>, and <i>Haemaphysalis concinna</i> ranging 20.1%-24.0%. Thirteen factors including woodland, NDVI, rainfed cropland, and livestock density were determined as important drivers for the probability of <i>B. burgdorfer</i>i occurrence based on the stage 1 model. The stage 2 model identified ten factors including temperature seasonality, NDVI, and grasslands that were the main determinants used to distinguish areas at high or low-medium risk of <i>B. burgdorferi</i>, interpreted as potential occurrence areas within the area projected by the stage 1 model. The projected high-risk areas were not only concentrated in high latitude areas, but also were distributed in middle and low latitude areas. These high-resolution evidence-based risk maps of <i>B. burgdorferi</i> was first created in China and can help as a guide to future surveillance and control and help inform disease burden and infection risk estimates.