BACKGROUND: Japanese spotted fever (JSF) mainly occurs in Japan; however, it has been increasingly reported in China. JSF is typically characterized by fever, rash, and eschar, in addition to non-specific symptoms. Yet, reports on the pulmonary indicators in JSF are limited. Herein, we report an unusual case of JSF associated with pleural effusion and pneumonia, in which the pathogen was identified via blood next-generation sequencing (NGS).
METHODS: We report a case of a 33-year-old woman who presented with fever for five days, rash for two days, and myalgia, fatigue, and edema for one day. She had recently been on vacation when an unknown insect bit her. The doctors at the local primary hospital considered a bacterial infection and administered dexamethasone, ceftriaxone, indomethacin, and anti-allergy agents, but the symptoms persisted. A rash without pruritus or pain developed gradually over the entire body and face. We considered rickettsial infection and administered doxycycline and levofloxacin. Metagenomic NGS from blood confirmed the presence of Rickettsia japonica (R. japonica). Abdominal computed tomography revealed bilateral pleural effusion with two atelectasis; patchy shadows with blurred edges, and uniform enhancement in both lower lungs. After several days of treatment, the symptoms and laboratory results improved. A literature review of the epidemiology of R. japonica and JSF in China, characteristics of JSF, and related pulmonary changes, and technology to diagnose JSF is provided.
CONCLUSIONS: JSF has a variety of symptoms and is becoming increasingly popular in China. Clinical doctors need to identify it carefully.

A 71-year-old male had disseminated multiple organ dysfunction syndrome (MODS). Following treatment with cefotaxime and piperacillin-tazobactam, his symptoms have worsened instead. Multiple organ failure caused by Japanese Spotted Fever (JSF) was diagnosed based on metagenomic next-generation sequencing (mNGS), we rapidly treated the patient with doxycycline. Thereafter, his symptoms gradually improved. In this report, we emphasized the importance of rapid microbial diagnostic tools and the early use of tetracyclines for the treatment of JSF.

UNASSIGNED: Rickettsia japonica infection is a rare disease, it is rare to report critical and severe case caused by this disease in Zhejiang Province, China.
UNASSIGNED: We report a patient who initially sought medical attention due to fever and developed coma and convulsions during treatment. The patient did not develop typical eschar and rash. Eventually, the patient needed to be treated in the intensive care unit due to acute respiratory failure.
UNASSIGNED: The patient was diagnosed with Rickettsia japonica bloodstream infection by metagenomic next-generation sequencing (mNGS).
UNASSIGNED: Due to the critical illness, the patient was transferred to the intensive care unit, received doxycycline and other treatments, and rapidly recovered and discharged.
UNASSIGNED: The patient developed a critical illness after being infected with Rickettsia, when the medical history is unclear and clinical symptoms and signs are atypical, it is necessary to use mNGS examination for diagnosis.

Japanese spotted fever (JSF) is a tick-transmitted infection caused by Rickettsia japonica (R. japonica), which is indigenous to Japan. Patients with JSF typically present with fever and spotted erythema on the palms and/or soles, and most of them have site(s) of tick bites. The prognosis is good, but some cases have a fatal course. Kawasaki disease (KD) is a systemic vasculitis with an unknown cause that is characterized by symptoms such as fever, conjunctival injection, oral findings, amorphous rash, rigid edema, and nonsuppurative cervical lymphadenopathy. Although the symptoms of JSF are partially similar to those of KD, case reports of JSF overlapping KD have never been internationally published. Herein, we report a boy with JSF and KD symptoms. A five-year-old boy presented with fever and rash after he had been on a mountain inhabited by R. japonica. On the fifth day, erythema was spotted mainly on his bilateral palms, bilateral cervical lymphadenopathy, rigid edema of his lower feet, and mild conjunctival injection appeared. Intravenous immunoglobulin (IVIG) therapy was performed because these symptoms satisfied five out of the six diagnostic criteria for KD. However, on the sixth day, the fever persisted, and then we readministered IVIG in addition to tosufloxacin and azithromycin since we found a tick-bite eschar, which suggested a complication of JSF. His symptoms resolved soon after this treatment. Coronary artery lesions were never observed. This case indicates that the R. japonica infection overlaps clinically with KD. Tosufloxacin and azithromycin should be considered to avoid the use of minocycline in younger patients with JSF.

UNASSIGNED: Japanese spotted fever (JSF) is a rare disease, caused by Rickettsia japonica; no case has been reported in Zhejiang Province, China.
UNASSIGNED: An elderly woman presented to the hospital with abdominal pain and fever. Her condition rapidly worsened with severe complications, such as multiple organ failure and central nervous system damage. The presence of R. japonica was quickly detected by metagenomic next-generation sequencing. On the basis of combined clinical manifestations and laboratory results, critical JSF was diagnosed and treated with doxycycline. The patient showed good prognosis. Typical symptoms (eschar and rash) were not observed in the early stage, consequently increasing the difficulty of clinical diagnosis.
UNASSIGNED: The delay of treatment caused by non-specific symptoms is an important factor affecting the progression of JSF. As an emerging pathogen detection method, mNGS has been successfully applied for disease diagnosis and treatment, and can be an important complement for the diagnosis of this disease.

We report a case-series study of 5 patients with Japanese spotted fever from the Three Gorges Area in China, including 1 fatal case. Seroprevalence of Rickettsia japonica was ≈21% among the local population. Our report highlights the emerging potential threat to human health of Japanese spotted fever in the area.