Clinical characteristics analysis of five cases of Japanese spotted fever rickettsia infection

Abstract

This study aimed to analyze the clinical characteristics and treatment strategies of Japanese spotted fever (JSF) cases clustered in the same region over a short period, to provide clinical insights for the diagnosis and management of similar cases. Data of 5 JSF cases admitted to Dazhu County, Sichuan and surrounding areas from May to September 2025 were collected. Epidemiological features, clinical manifestations, laboratory/auxiliary findings, treatment regimens and prognoses were systematically analyzed, and common points in diagnosis and management were summarized. One severe and four mild cases were included, all with long-term residence in Dazhu and surrounding endemic areas; four had outdoor exposure, while the severe case had potential vector exposure in a domestic environment with reported rodent presence. All presented with fever and rash: the severe case had myalgia, diarrhea, septic shock and multiple organ dysfunction, while mild cases mainly had abnormal liver function and hypokalemia. Laboratory abnormalities included elevated neutrophil percentage/C-reactive protein increased, alanine transaminase/aspartate transaminase, and had chest CT-proven lung infection. All received doxycycline: mild cases with monotherapy or combined with piperacillin-tazobactam/symptomatic care (hepatoprotection, potassium supplementation); the severe case additionally received platelet-elevating agents, fluid resuscitation, acid correction, anti-shock therapy, albumin and multi-organ support. All 5 patients were cured after standardized treatment. Early identification, targeted anti-infective therapy and multi-organ support are crucial for JSF prognosis, offering supportive observations for regional rickettsial infection prevention and control. Not applicable.