Urbanization and scrub typhus expansion in temperate settings

Urbanization is increasingly shifting the ranges of vector-borne diseases, including in temperate regions. In China, scrub typhus (ST), a bacterial vector-borne disease, was endemic exclusively in southern, tropical and extratropical provinces, but has surged northward in recent years. Here we use a comparative framework and focus on Jiangsu Province to investigate how urbanization modulates ST risks in temperate urban settings. Since 2014, infections have surged and expanded spatially. Additionally, ST is disproportionately afflicting populations along the urban–rural gradient, yet greater urbanization and human impacts are associated with an increased urban fraction of cases. Conversely, aging populations are associated with a lower proportion of urban cases. Our findings collectively underscore that ST expansion can be rapid in temperate regions under urbanization, although population aging may partially counteract this effect. Informed surveillance and management of disease expansion in urban settings is crucial for informing public health strategies. Urbanization and changing climate affect humans as well as our scourges. Focusing on Jiangsu Province, China, this study finds that scrub typhus, a bacterial vector-borne disease associated with the tropics, is expanding in temperate urban settings.