Severe fever with thrombocytopenia syndrome (SFTS) is a tick-borne illness with a notable morality risk that is becoming increasingly prevalent in East Asia (14-36%). Increasing evidence indicates a more direct role of the SFTS virus in renal impairment. However, few studies have explored the risk factors for and clinical outcomes of AKI in patients with SFTS. Therefore, in this study, we aimed to investigate risk factors and outcomes associated with AKI in patients with SFTS. In this retrospective cohort study, we included the data of 53 patients who were diagnosed with SFTS virus infection at Kangwon National University Hospital between 2016 and 2020. We incorporated laboratory data and medical information including comorbidities, complications, and mortality. Baseline characteristics, clinical features, laboratory parameters, and mortality rates of the non-AKI and AKI groups were compared. Patient survival of non-AKI and AKI groups were compared using the Kaplan-Meier method. To identify the population with poor prognosis, Cox regression analysis was used to identify the independent risk factors for in-hospital mortality in patients with SFTS. Of the 53 individuals, 29 (54.7%) were male, with an average age of 66.5 years. Nine patients (15.1%) died of SFTS. Twenty-seven (50.9%) patients exhibited AKI; the average time interval from fever onset to AKI occurrence was 3.6 days. Notably, 24 (88.9%) patients developed AKI within the first week of fever onset. Patients in the AKI group exhibited a significantly higher prevalence of diabetes and were older than those in the non-AKI group. The mortality rate was notably higher (29.6%) in the AKI group than in the non-AKI group (3.8%). Within the AKI cohort, advanced stages (stages 2 and 3) showed a 50% mortality rate, which was significantly higher than the 17.6% mortality rate in patients with stage 1 AKI. Additionally, Kaplan-Meier curves revealed lower survival rates among patients with AKI than among those without AKI (P = 0.017). Cox regression analysis identified leukopenia and elevated serum creatinine levels as significant risk factors for mortality. AKI is a common complication associated with SFTS. Moreover, the mortality rate was significantly higher in the patients who developed AKI than in those who did not. Our findings underscore the pivotal role of AKI as a prognostic marker of disease severity in patients with SFTS.

Severe fever with thrombocytopenia syndrome (SFTS) is a recently identified infectious ailment triggered by a new strain of bunyavirus. It is distinguished by elevated fatality rates, ranging from 12 % to 30 %. The mechanism underlying the development of severe illness caused by SFTS bunyavirus (SFTSV) is not yet fully understood. To evaluate the role of the TLR2 receptor pathway in regulating Treg function in the progression of SFTS disease and possible mechanisms, sequential serum samples from 29 patients with SFTS (15 mild, 14 severe cases) were examined. Flow cytometry was employed to scrutinize the phenotypic and functional characteristics of TLR2 expression on circulating CD4 T cells, CD8 T cells, and Tregs. In all admitted patients, the evaluation of correlations between the frequencies of the aforementioned cells and SFTS index (SFTSI) was conducted. For SFTS, the levels of TLR2 on CD4 T cells and Tregs were significantly heightened when compared to those in healthy subjects. Additionally, the expression of TLR2 on Tregs exhibited a positive correlation with Ki-67 expression in Tregs and the severity of disease. Additionally, compared with those in uninfected controls, the expression levels of NF-κB in Tregs were significantly increased. Collectively, Tregs may be activated and proliferate through the stimulation of the TLR2/NF-кB pathway in reaction to SFTSV infection.

Severe fever with thrombocytopenia syndrome (SFTS) is a newly identified tick-borne viral hemorrhagic fever caused by Dabie Banda virus (DBV). The virus was first discovered in eastern China in 2009 and is now considered an infectious disease with a mortality rate ranging from 6.3% to 30%. The best strategy for controlling SFTS is to develop effective vaccines. However, no approved vaccines are currently available to prevent this disease, despite the number of extensive and in-depth studies conducted on DBV in the past few years. This review focuses on the structure of DBV and the induced host immune responses which are the fundamental factors in vaccine development, and thoroughly summarizes the current research progress on DBV vaccines. The developing DBV vaccines include protein subunit vaccines, live attenuated vaccines, recombinant virus vector vaccines, and DNA vaccines. At present, almost all candidate vaccines for DBV are in the laboratory development or preclinical stages. There remain challenges in successfully developing clinically approved DBV vaccines.

Severe fever with thrombocytopenia syndrome virus (SFTSV), also known as the Dabie Banda virus, is an emerging tick-borne Bunyavirus that causes severe fever with thrombocytopenia syndrome (SFTS). Currently, symptomatic treatment and antiviral therapy with ribavirin and favipiravir are used in clinical management. However, their therapeutical efficacy is hardly satisfactory in patients with high viral load. In this study, we explored the antiviral effects of selective estrogen receptor modulators (SERMs) on SFTSV infection and the antiviral mechanisms of a representative SERM, bazedoxifene acetate (BZA). Our data show that SERMs potently inhibited SFTSV-induced cytopathic effect (CPE), the proliferation of infectious viral particles, and viral RNA replication and that BZA effectively protected mice from lethal viral challenge. The mode of action analysis reveals that BZA exerts antiviral effects during the post-entry stage of SFTSV infection. The transcriptome analysis reveals that GRASLND and CYP1A1 were upregulated, while TMEM45B and TXNIP were downregulated. Our findings suggest that SERMs have the potential to be used in the treatment of SFTSV infection.

Severe fever with thrombocytopenia syndrome virus (SFTSV) is a tick-borne virus recognized by the World Health Organization as an emerging infectious disease of growing concern. Utilizing phylodynamic and phylogeographic methods, we have reconstructed the origin and transmission patterns of SFTSV lineages and the roles demographic, ecological, and climatic factors have played in shaping its emergence and spread throughout Asia. Environmental changes and fluctuations in tick populations, exacerbated by the widespread use of pesticides, have contributed significantly to its geographic expansion. The increased adaptability of Lineage L2 strains to the Haemaphysalis longicornis vector has facilitated the dispersal of SFTSV through Southeast Asia. Increased surveillance and proactive measures are needed to prevent further spread to Australia, Indonesia, and North America.

BACKGROUND: Severe fever with thrombocytopenia syndrome (SFTS) is a novel tick-borne infectious disease with a high fatality rate. Although several nomograms based on demographic and laboratory data have been reported to predict the prognosis of SFTS in recent studies, baseline serum glycated albumin (GA)/albumin (ALB) ratio included risk model has not been evaluated for the prediction of clinical outcome.
METHODS: A total of 214 SFTS patients with integral data admitted to our hospital from May, 2020 to November, 2022 were included in this study. SFTS infection was confirmed by real time fluorescent quantitative PCR (qRT-PCR). The demographic characteristics, clinical and laboratory data were collected with in 24 h of admission and 1 to 2 days before discharge and were analysed retrospectively.
RESULTS: Fiffty-seven patients (26.6%) died. Multivariate logistic regression analysis showed that age, aspartate aminotransferase (AST), blood glucose (GLU), GA/ALB ratio, neutrophil counts (NEU) and lymphocyte percentage (LYM%) were the independent risk factors for mortality. A nomogram by these factors was created using RMS package in the R program. Area under the receiver operating characteristic (ROC) curve (AUC) of this nomogram was 0.88 (95% CI: 0.83, 0.93). This model showed the excellent net benefit, as revealed by the decision curve analysis. GA/ALB ratios were also independent risk factors for poor out clinical come in subgroups of patients with hyperglycemia on admission and with diabetes history. Nomograms were constructed by the independent risk factors in the subgroups. AUCs of the nomograms in the subgroups showed high predictive values for adverse prognosis.
CONCLUSIONS: GA/ALB ratios were independent risk factors for mortality in all SFTS patients and subgroups of with hyperglycemia on admission and diabetes history. The nomograms including GA/ALB ratio had high predictive value for adverse clinical outcome.The nomograms provide a basis for clinical decision-making for the treatment of SFTS patients in different clinical settings.

UNASSIGNED: Severe fever with thrombocytopenia syndrome (SFTS) is prevalent in East Asia. However, the use of glucocorticoids (GCs) in the treatment of SFTS remains controversial.
UNASSIGNED: In this retrospective cohort study, we collected the data from patients with SFTS at Wuhan Union Hospital to evaluate the effect of GC therapy. Mortality and secondary infections were compared as outcomes. After searching public databases, we also included articles that examined GC use in patients with SFTS for meta-analysis.
UNASSIGNED: Patients treated with GC had higher fatality rates (21.1% vs. 11.9%, respectively; P=0.006) and a longer length of stay (10.6 ± 5.1 vs. 9.5 ± 4.2, respectively; P=0.033). In cohorts adjusted using propensity score matching and inverse probability of treatment weighting, no significant differences in fatality rates and length of stay were observed. A meta-analysis of 4243 SFTS patient revealed that those treated with GCs had significantly higher mortality (OR=3.46, 95% CI =2.12-5.64, P<0.00001) and secondary infection rate (OR=1.97, 95% CI=1.45-2.67, P<0.0001).
UNASSIGNED: GC should be used cautiously when treating SFTS. No significant differences were identified in terms of mortality and secondary infection rates between patients with SFTS treated with or without GC.

Severe fever with thrombocytopenia syndrome virus (SFTSV) is an emerging bunyavirus that causes severe viral hemorrhagic fever and thrombocytopenia syndrome with a fatality rate of up to 30%. No licensed vaccines or therapeutics are currently available for humans. Here, we develop seven monoclonal antibodies (mAbs) against SFTSV surface glycoprotein Gn. Mechanistic studies show that three neutralizing mAbs (S2A5, S1G3, and S1H7) block multiple steps during SFTSV infection, including viral attachment and membrane fusion, whereas another neutralizing mAb (B1G11) primarily inhibits the viral attachment step. Epitope binning and X-ray crystallographic analyses reveal four distinct antigenic sites on Gn, three of which have not previously been reported, corresponding to domain I, domain II, and spanning domain I and domain II. One of the most potent neutralizing mAbs, S2A5, binds to a conserved epitope on Gn domain I and broadly neutralizes infection of six SFTSV strains corresponding to genotypes A to F. A single dose treatment of S2A5 affords both pre- and post-exposure protection of mice against lethal SFTSV challenge without apparent weight loss. Our results support the importance of glycoprotein Gn for eliciting a robust humoral response and pave a path for developing prophylactic and therapeutic antibodies against SFTSV infection.

BACKGROUND: The geographic spread of Japanese spotted fever (JSF) in China is gradually expanding, particularly in regions where severe fever with thrombocytopenia syndrome (SFTS) is highly prevalent, with both diseases sharing similarities in epidemiology and clinical presentation. The microbiological diagnosis of JSF is challenging, compounded by low awareness among healthcare professionals in newly affected areas. Moreover, primary healthcare facilities without polymerase chain reaction (PCR) testing capabilities for SFTS often misdiagnose JSF as SFTS.
METHODS: All 3 patients had a history of working in the fields, with cold like symptoms in the early fever stages, but the fever did not improve after a few days. The accompanying symptoms were also very different. Physical examination revealed enlarged lymph nodes, different forms of rash, with or without eschar. Laboratory tests showed thrombocytopenia, eosinophilia, elevated lactate dehydrogenase, and transaminase, with 1 patient experiencing renal damage. It is worth noting that these 3 patients reside in an area where SFTS is endemic, and there have been no prior reports of JSF. They exhibited clinical symptoms and laboratory test results closely resembling those of SFTS. Therefore, they were initially misdiagnosed with SFTS in their local hospitals.
METHODS: The 3 patients who arrived at our hospital 7 days after symptom onset and were subsequently diagnosed with JSF by metagenomic next-generation sequencing (mNGS).
METHODS: Doxycycline treatment for 1 week.
RESULTS: The patients\' symptoms quickly improved with no side effects, and the results of laboratory tests went back to normal.
CONCLUSIONS: By comparing the clinical characteristics of JSF patients and SFTS patients comprehensively, we found that APTT and procalcitonin levels may be valuable in assisting in the identification of SFTS and JSF. In all areas where tick-borne diseases are endemic, include SFTS-epidemic areas, we recommend using the Weil-Felix test to screen for potential rickettsiosis in patients presenting with fever and thrombocytopenia with or without rash in primary healthcare settings, as well as simultaneous testing for the SFTS virus and spotted fever group rickettsioses sequence. Additionally, mNGS sequencing should be used to confirm the diagnosis and provide information for epidemiological investigations in patients who are suspected of having spotted fever group rickettsiosis.

BACKGROUND: Epstein-Barr virus (EBV) can be reactivated and proliferated with fatal outcome in immuno-compromised people, but the clinical consequences of EBV infection in patients with severe fever with thrombocytopenia syndrome (SFTS) remain uncertain. In this study, we investigated the infection rate, the influence and the early predictors of EBV infection in SFTS patients.
METHODS: In this retrospective study, SFTS patients who were treated in the First Affiliated Hospital of Nanjing Medical University from May 2011 to August 2021 were enrolled and divided into infected and non-infected groups. We compared the demographic characteristics, clinical manifestations and signs, laboratory tests and prognosis, and explored the risk factors of EBV infection by receiver operating characteristic (ROC) curve and logistic regression.
RESULTS: A total of 120 hospitalized SFTS patients with EBV-DNA testing were enrolled in this study. Patients with EBV infection had statistically significant higher mortality rate (32.0% vs. 11.43%, P = 0.005). Compared with the non-infected group, the EBV-infected group had higher levels of C-reactive protein (CRP), creatine-kinase (CK), fasting blood glucose (FBG), blood urea nitrogen (BUN), D-dimer, and CD56+ cell counts, lower levels of immunoglobulin G (IgG), IgM, complement 3 (C3), and C4. The proportion of patients with age ≥ 60 years and ferritin > 1500.0 ng/ml in the EBV-infected group was significantly higher than that in the non-infected group. The results of ROC analysis showed that the cut-off values of CRP, IgG, C3, C4, and CD56+ cell counts to predict EBV infection were 13.2 mg/l, 12.5 g/l, 1.1 g/l, 0.6 g/l, 0.3 g/l, and 94.0 cells/µl. Multivariable logistic analysis showed that age ≥ 60 years old, CRP > 13.2 mg/l, BUN > 5.4 mmol/l, ferritin > 1500.0 ng/ml, IgG < 12.5 g/l, IgM < 1.1 g/l, C4 < 0.3 g/l, and CD56+ cell counts > 94.0 cells/µl were the independent risk factors of EBV infection in SFTS patients.
CONCLUSIONS: SFTS combined with EBV infection is associated with high morbidity and mortality. It is necessary to strengthen screening for EBV infection and its early predictive markers after admission in SFTS patients.