biostudies-literatureYuan HXNational Natural Science Foundation of ChinaScience and Technology Program of the Joint Fund of Scientific Research for the Public Hospitals of Inner Mongolia Academy of Medical Sciences2502003https://www.ebi.ac.uk/biostudies/studies/S-EPMC12100960biostudies-literatureUnknown14(1)Wetland virus (WELV) is a recently identified segmented orthonairovirus associated with human febrile illness in northeastern China. To elucidate its ecological drivers and transmission patterns, we conducted multi-host surveillance in seven eco-climate regions across China through an integrated approach combining molecular and serological profiling. Over 33,000 questing and feeding ticks representing 11 species were systematically screened WELV-RNA alongside 1,493 wild small mammals, while 2,578 domestic animals and 3,921 patients presenting with outdoor field or tick exposure history underwent both WELV specific molecular and serological evaluation. WELV-RNA detection via real-time RT-PCR revealed low but widespread infection, including 0.54% (8/1,493) in wild rodents (<i>Apodemus chevriEmerging microbes & infectionsGenetic diversity and expanded epidemic area of novel tick-borne pathogen wetland virus in ticks, wild and domestic animals, and patient in China.PMC12100960823301032023GLLH0335Li HCui NZhao ZJChen MZhang XAZhang LHou ZJZhang MQLv XLLiu WYang XHan SZSi GQPeng CMu HZYuan HXHan XHBao PTMa YDWu SQfalseGenetic diversity and expanded epidemic area of novel tick-borne pathogen wetland virus in ticks, wild and domestic animals, and patient in China.Wetland virus (WELV) is a recently identified segmented orthonairovirus associated with human febrile illness in northeastern China. To elucidate its ecological drivers and transmission patterns, we conducted multi-host surveillance in seven eco-climate regions across China through an integrated approach combining molecular and serological profiling. Over 33,000 questing and feeding ticks representing 11 species were systematically screened WELV-RNA alongside 1,493 wild small mammals, while 2,578 domestic animals and 3,921 patients presenting with outdoor field or tick exposure history underwent both WELV specific molecular and serological evaluation. WELV-RNA detection via real-time RT-PCR revealed low but widespread infection, including 0.54% (8/1,493) in wild rodents (<i>Apodemus chevri2025-01-01T00:00:00Z2025 Dec2026-06-01T11:37:32.764Z2026-04-08T12:00:10.605ZS-EPMC121009604031422910.1080/22221751.2025.2502003