Li Jiarong, He Junning, Yin Yijie, Liu Yongfang
Department of Infectious Diseases, Third People's Hospital of Chengdu, Chengdu, China.
Department of Clinical Medicine, North Sichuan Medical College, Nanchong, China.
Medicine (Baltimore). 2025 Sep 5;104(36):e44345. doi: 10.1097/MD.0000000000044345.
Japanese spotted fever (JSF) is a rare tick-borne disease caused by Rickettsia japonica. Atypical manifestations and a lack of standardized diagnostic assays often result in delayed diagnosis and treatment, potentially leading to life-threatening complications.
A 57-year-old immunocompetent female from a region with no previously reported JSF cases presented with acute-onset high-grade fever (39.5°C), a generalized maculopapular rash, and systemic symptoms after participating in agricultural activities. The patient denied having any history of tick exposure and presented without eschar, leading to the initial misdiagnosis of respiratory infection.
Metagenomic sequencing (MetaCAP) technology enabled a definitive diagnosis by identifying Rickettsia japonica-specific DNA sequences in the patient's blood. The genomic results completely aligned with the clinical presentation.
The patient was treated with doxycycline, which achieved rapid clinical resolution.
The patient achieved full recovery with only residual lower-limb hyperpigmentation at the month follow-up, without disease recurrence.
This case demonstrates the diagnostic value of metagenomic testing for fevers of unknown origin. JSF should be a key consideration for agricultural and forestry workers presenting with compatible symptoms, even in nonendemic areas without documented insect bites. The optimal diagnostic approach combines clinical evaluation with advanced molecular testing to ensure the accurate identification and proper management of tropical febrile illnesses.
日本斑点热（JSF）是一种由日本立克次体引起的罕见蜱传疾病。非典型表现和缺乏标准化诊断检测方法常常导致诊断和治疗延迟，可能引发危及生命的并发症。
一名来自此前无日本斑点热病例报告地区的57岁免疫功能正常女性，在参与农业活动后出现急性高热（39.5°C）、全身性斑丘疹和全身症状。患者否认有蜱虫接触史，且无焦痂表现，最初被误诊为呼吸道感染。
宏基因组测序（MetaCAP）技术通过在患者血液中鉴定出日本立克次体特异性DNA序列得以明确诊断。基因组结果与临床表现完全相符。
患者接受强力霉素治疗，临床症状迅速缓解。
在随访的一个月时，患者完全康复，仅下肢留有色素沉着，无疾病复发。
该病例证明了宏基因组检测对不明原因发热的诊断价值。对于出现相关症状的农林工作者，即使在无昆虫叮咬记录的非流行地区，日本斑点热也应作为关键考虑因素。最佳诊断方法是将临床评估与先进的分子检测相结合，以确保准确识别和妥善管理热带发热性疾病。
