关键词: 恙虫病, 流行病学, 临床特征, 间接免疫荧光检测

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