目的：探讨小兴安岭林区莱姆病流行情况。方法：间接免疫荧光抗体试验（ＩＦＡ）、宿主调查、病原分离。结果：林区人群普遍易感，平均感染率１１７３％。确诊４８例莱姆病患者，临床症状以慢性游走性红斑（３３３３％）、关节炎（２７０９％）和神经系统损害（２７０９％）为主。全沟硬蜱是莱姆病螺旋体的主要生物媒介，属野鼠是重要动物宿主。从神经麻痹和游走性红斑病人、全沟硬蜱、棕背、花鼠分离出６株病原体。结论：首次确证该地区为莱姆病自然疫源地 Objective: To investigate the epidemic situation of Lyme disease in Xiaoxing’anling forest. Methods: Indirect immunofluorescence antibody test (IFA), host investigation, pathogen isolation. Results: The population in the forest area was generally susceptible, with an average infection rate of 1173%. The diagnosis of 48 cases of Lyme disease patients, clinical symptoms of chronic migratory erythema (33  33%), arthritis (27  09%) and nervous system damage (27  09%) based. Ixodes nodosum is the major biological mediator of Lyme disease, which is an important animal host. Six pathogens were isolated from neuroparalytic and migratory erythema patients, Ixodes nigricans, brown backfat, and rat. Conclusions: For the first time it is confirmed that the area is the natural foci of Lyme disease