目的 调查浙江省杭州市余杭区首例日本斑点热（JSF）病例的临床表现和感染来源,为JSF的防控提供依据。方法 对病例进行个案调查,用病原微生物宏基因组测序（mNGS）对病例进行病原体检测,开展病例搜索、流行病学调查、媒介生物监测,了解病例临床表现与诊疗情况,分析感染来源。结果 病例临床表现为发热、头痛、全身点状红斑等,继发凝血功能障碍、感染性休克、多脏器功能衰竭、急性呼吸窘迫综合征；临床检查外周血小板减少（最低14×109/L）、白细胞升高（最高23.33×109/L）、超敏C反应蛋白升高（最高200.50 mg/L）、D-二聚体升高（最高24 840 μg/L纤维蛋白原当量）,肺泡灌洗液和血液mNGS检出日本立克次体,经抗感染及对症治疗后痊愈。病例搜索未发现其他病例。病例发病前1周内有多次野外活动史,有疑似蜱虫叮咬史,病例曾活动地区游离蜱密度指数为7.40只/（布旗·100 m）,种类为长角血蜱。结论 该病例确诊为杭州市余杭区首例JSF病例,感染来源可能为当地蜱虫。病例活动地区游离蜱密度较高,应加强JSF防控工作,开展病例监测、灭蜱防蜱、健康宣教等工作。
Objective To investigate the clinical manifestations and source of infection of the first case of Japanese spotted fever (JSF) in Yuhang District, Hangzhou, Zhejiang Province, China, so as to provide evidence for the prevention and control of JSF. Methods A individual case investigation was conducted, and the case was tested for pathogenic microorganisms using metagenomic next-generation sequencing (mNGS). Meanwhile, case search, epidemiological investigation, and vector surveillance were carried out. The clinical manifestations, diagnosis, and treatment of the case were analyzed to determine the source of infection. Results The case presented with fever, headache, generalized punctate erythema, and secondary coagulation disorder, septic shock, multiple organ failure, and acute respiratory distress syndrome. Clinical examinations showed decreased peripheral platelet count (lowest level: 14×109/L), increased white blood cell count (highest level: 23.33×109/L), elevated hypersensitive C-reactive protein (highest level: 200.50 mg/L), and increased D-dimer (highest level: 24 840 μg/L FEU). Rickettsia japonica was detected in bronchoalveolar lavage fluid and blood using mNGS, and the patient recovered after anti-infection and symptomatic treatment. No additional cases were identified in the case search. The patient had a history of multiple outdoor activities and suspected tick bites within one week before the onset of the disease. The density index of free-living ticks in the areas where the patient was active was 7.40 inds per flagged 100 meters, with the species being Haemaphysalis longicornis. Conclusions This is the first case of JSF in Yuhang District of Hangzhou, with the possible source of infection being local ticks. Considering the high density of free-living ticks in the areas where the case was active, it is necessary to strengthen the prevention and control of JSF and carry out case surveillance, tick control and prevention, and health education.
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