Abstract: Objective To investigate and analyze an outbreak of tsutsugamushi disease occurred in Rongjiang County, Guizhou Province, China, in 2022 in terms of onset characteristics, epidemiological characteristics and influence factors for infection, so as to provide a basis for formulating targeted prevention and control measures.Methods A uniform questionnaire was used to conduct an epidemiological survey, and indirect immunofluorescence assay was used to detect the serum samples of cases. Medical records were collected, and a host survey was conducted. Descriptive epidemiology was used to analyse the data.Results A total of 20 cases of tsutsugamushi disease were identified according to the case definition, all of whom were farmers in terms of occupation, and the epidemiological survey showed that 14 patients had been to the riverside of Duliu River. There were 9 confirmed cases, 3 clinical cases, and 8 suspected cases. All patients had the symptom of pyrexia; the patients with fear of cold and headaches accounted for 65.00% and 55.00%, respectively, those with weakness and generalized aches and pains accounted for 45.00% and 30.00%, respectively, and those with specific eschar only accounted for 25.00%. Indirect immunofluorescence assay was used to detect 8 serum samples, among which 5 samples had an IgG antibody with the titer of ≥1∶128, and 5 samples showed a 4-fold increase in antibody in the convalescence stage. The mean time from onset to consultation was 5.85 days, and the mean time from consultation to diagnosis was 2.80 days.Conclusions This is a typical outbreak of tsutsugamushi disease, with the main clinical symptoms of pyrexia, fear of cold, and headache. Activities along the river after rainstorm and flood may increase the risk of the disease. The long incubation period and atypical early symptoms of tsutsugamushi disease and a lack of awareness of the disease among local villagers and clinicians are the main factors for failing to identify and dispose this epidemic in a timely manner. It is recommended to strengthen health education, and “early warning, early identification, early diagnosis, and early treatment” of tsutsugamushi disease, to effectively reduce the harm of such diseases to human health.

Key words: Tsutsugamushi disease, Epidemiology, Clinical features, Indirect immunofluorescence assay

摘要： 目的 对2022年贵州省榕江县恙虫病突发疫情进行分析,探索其发病特点及流行特征,分析感染影响因素,为制定防制措施提供依据。方法 采用统一问卷开展流行病学调查,采用间接免疫荧光法检测病例血清,收集病历资料同时开展宿主调查。采用描述流行病学方法对数据进行分析。结果 依据病例定义共发现恙虫病病例20例,其发病病例职业均为农民,在流行病学调查中有14例曾在都柳江边活动。其中确诊病例9例,临床病例3例,疑似病例8例。病例均有发热,有畏寒和头痛症状者分别占65.00%和55.00%,乏力和全身酸痛者分别占45.00%和30.00%,特异性焦痂者仅占25.00%。通过间接免疫荧光法检测病例血清8份,IgG抗体滴度≥1∶128的5份,其中恢复期抗体呈4倍增高的有5份。发病至就诊时间平均为5.85 d,就诊至诊断时间平均为2.80 d。结论 本次疫情为一起恙虫病暴发疫情,临床症状上主要表现为发热、畏寒和头痛等；暴雨洪水后,在河边活动有可能增加患病风险；恙虫病潜伏期长、早期症状不典型、当地村民及临床医生对该疾病认识不足等因素是本次疫情发现及处置不及时的主要因素。建议加强恙虫病健康教育,“早预警、早发现、早诊断、早治疗”,有效降低该类疾病对人群健康的危害。

关键词: 恙虫病, 流行病学, 临床特征, 间接免疫荧光检测