The use of glucocorticoid in severe fever with thrombocytopenia syndrome: a retrospective cohort study.

Introduction: Severe fever with thrombocytopenia syndrome (SFTS) is prevalent in East Asia. However, the use of glucocorticoids (GCs) in the treatment of SFTS remains controversial. Methods: 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. Results: 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). Discussion: 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.

Comparison of epidemiological characteristics between hemorrhagic fever with renal syndrome patients and severe fever with thrombocytopenia syndrome patients.

Hemorrhagic fever with renal syndrome (HFRS) and severe fever with thrombocytopenia syndrome (SFTS) are both endemic in rural areas and some characteristics are similar between HFRS and SFTS, which usually lead to misdiagnosis. In this study, we summarized and compared some characteristics of HFRS and SFTS which will provide scientific information for differential diagnosis. From 2011 to 2022, a total of 4336 HFRS cases and 737 SFTS cases were reported in Zhejiang Province. Compared to SFTS, there was a higher proportion of males among HFRS cases (72.46% [3142/4336] vs. 50.88% [375/737], p = 0.000). The median age of all 4336 HFRS cases was 49 (39, 59), while the median age of SFTS cases was 66 (57, 74). In addition, the involved counties of HFRS were more than SFTS, but the number of counties affected by SFTS increased from 2011 to 2022. The majority of SFTS cases occurred in summer (from May to July), but besides summer, HFRS cases also showed a peak in winter. Finally, our results showed that the case fatality rate of SFTS was significantly higher than that of HFRS. Although there were some similarities between HFRS and SFTS, our study found several differences between them, such as gender distribution, age distribution, and seasonal distribution, which will provide scientific information for differential diagnosis of HFRS and SFTS. Further studies should be carried out to explore the mechanism of these differences.

Deciphering the evolutionary landscape of severe fever with thrombocytopenia syndrome virus across East Asia.

Severe fever with thrombocytopenia syndrome virus (SFTSV) poses a significant public health challenge in East Asia, necessitating a deeper understanding of its evolutionary dynamics to effectively manage its spread and pathogenicity. This study provides a comprehensive analysis of the genetic diversity, recombination patterns, and selection pressures across the SFTSV genome, utilizing an extensive dataset of 2041 sequences from various hosts and regions up to November 2023. Employing maximum likelihood and Bayesian evolutionary analysis by sampling trees (BEAST), we elucidated the phylogenetic relationships among nine distinct SFTSV genotypes (A, B1, B2, B3, B4, C, D, E, and F), revealing intricate patterns of viral evolution and genotype distribution across China, South Korea, and Japan. Furthermore, our analysis identified 34 potential reassortments, underscoring a dynamic genetic interplay among SFTSV strains. Genetic recombination was observed most frequently in the large segment and least in the small segment, with notable recombination hotspots characterized by stem-loop hairpin structures, indicative of a structural propensity for genetic recombination. Additionally, selection pressure analysis on critical viral genes indicated a predominant trend of negative selection, with specific sites within the RNA-dependent RNA polymerase and glycoprotein genes showing positive selection. These sites suggest evolutionary adaptations to host immune responses and environmental pressures. This study sheds light on the intricate evolutionary mechanisms shaping SFTSV, offering insights into its adaptive strategies and potential implications for vaccine development and therapeutic interventions.

Activation of neurotoxic A1-reactive astrocytes by SFTS virus infection accelerates fatal brain damage in IFNAR1-/- mice.

Severe fever with thrombocytopenia syndrome (SFTS) has a high mortality rate compared to other infectious diseases. SFTS is particularly associated with a high risk of mortality in immunocompromised individuals, while most patients who die of SFTS exhibit symptoms of severe encephalitis before death. However, the region of brain damage and mechanisms by which the SFTS virus (SFTSV) causes encephalitis remains unknown. Here, we revealed that SFTSV infects the brainstem and spinal cord, which are regions of the brain associated with respiratory function, and motor nerves in IFNAR1-/- mice. Further, we show that A1-reactive astrocytes are activated, causing nerve cell death, in infected mice. Primary astrocytes of SFTSV-infected IFNAR1-/- mice also induced neuronal cell death through the activation of A1-reactive astrocytes. Herein, we showed that SFTSV induces fatal neuroinflammation in the brain regions important for respiratory function and motor nerve, which may underlie mortality in SFTS patients. This study provides new insights for the treatment of SFTS, for which there is currently no therapeutic approach.

Early predictors of Epstein-Barr virus infection in patients with severe fever with thrombocytopenia syndrome.

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.

Factors Associated With the Spatial Distribution of Severe Fever With Thrombocytopenia Syndrome in Zhejiang Province, China: Risk Analysis Based on Maximum Entropy.

Background: Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease that was first identified in mainland China in 2009 and has been reported in Zhejiang Province, China, since 2011. However, few studies have focused on the association between ticks, host animals, and SFTS. Objective: In this study, we analyzed the influence of meteorological and environmental factors as well as the influence of ticks and host animals on SFTS. This can serve as a foundational basis for the development of strategic policies aimed at the prevention and control of SFTS. Methods: Data on SFTS incidence, tick density, cattle density, and meteorological and environmental factors were collected and analyzed using a maximum entropy-based model. Results: As of December 2019, 463 laboratory-confirmed SFTS cases were reported in Zhejiang Province. We found that the density of ticks, precipitation in the wettest month, average temperature, elevation, and the normalized difference vegetation index were significantly associated with SFTS spatial distribution. The niche model fitted accurately with good performance in predicting the potential risk areas of SFTS (the average test area under the receiver operating characteristic curve for the replicate runs was 0.803 and the SD was 0.013). The risk of SFTS occurrence increased with an increase in tick density, and the response curve indicated that the risk was greater than 0.5 when tick density exceeded 1.4. The risk of SFTS occurrence decreased with increased precipitation in the wettest month, and the risk was less than 0.5 when precipitation exceeded 224.4 mm. The relationship between elevation and SFTS occurrence showed a reverse V shape, and the risk peaked at approximately 400 m. Conclusions: Tick density, precipitation, and elevation were dominant influencing factors for SFTS, and comprehensive intervention measures should be adjusted according to these factors to reduce SFTS incidence in Zhejiang Province.

Analysis of early warning indicators of death in patients with severe fever with thrombocytopenia syndrome.

BACKGROUND: Since its discovery, severe fever with thrombocytopenia syndrome (SFTS) has been characterized by rapid progression and poor prognosis, and no specific treatment is available. The aim of this study was to investigate the early warning indicators of mortality in SFTS patients. METHODS: This is a retrospective cross-sectional study. The study subjects were patients who were admitted to the hospital with a confirmed diagnosis of SFTS from January 2023 to October 2023, and their clinical symptoms and signs at the time of admission, as well as the laboratory indexes of the first blood collection after admission were collected, grouped according to the prognosis, and statistically analyzed. RESULTS: A total of 141 patients were collected, of which 27 patients died and 114 patients were in the survival group. Through statistical analysis, patients with combined hemorrhagic manifestations, disturbance of consciousness, lymphopenia, elevated lipase, and prolonged thrombin time on admission were independent risk factors for patients' death. By plotting the working characteristic curve of the subjects, as well as calculating the area under the curve, the results showed that the AUC of lymphopenia count was 0.670, 95% CI (0.563-0.776), P = 0.006; the AUC of elevated serum lipase index was 0.789, 95% CI (0.699-0.878), p < 0.001; the AUC of prolonged thrombin time was 0.749, 95% CI (0.645-0.854), p < 0.001. CONCLUSION: Patients with hemorrhagic manifestations, disturbance of consciousness, lymphocyte reduction, elevated serum lipase, and prolonged thrombin time on admission are more worthy of the clinician's attention, and require early and effective interventions to avoid further disease progression.

Viral shedding pattern of severe fever with thrombocytopenia syndrome virus in severely ill patients: A prospective, Multicenter cohort study.

Background: Severe fever with thrombocytopenia syndrome (SFTS) is spreading rapidly in Asia. The pathway of SFTS virus shedding from patient and specific use of personal protective equipments (PPEs) against viral transmission have rarely been reported. The study was to determine SFTS virus (SFTSV) shedding pattern from the respiratory, digestive and urinary tract to outside in patients. Methods: Patients were divided into mild and severe groups in three sentinel hospitals for SFTS in Anhui province from April 2020 to October 2022. SFTSV level from blood, throat swabs, fecal/anal swabs, urine and bedside environment swabs of SFTS patients were detected by qRT-PCR. Specific PPEs were applied in healthcare workers contacting with the patients who had oropharyngeal virus shedding and hemorrhagic signs. Results: A total of 189 SFTSV-confirmed patients were included in the study, 54 patients died (case fatality rate, 28.57 %). Positive SFTSV in throat swabs (T-SFTSV), fecal/anal swabs (F-SFTSV) and urine (U-SFTSV) were detected in 121 (64.02 %), 91 (48.15 %) and 65 (34.4 %) severely ill patients, respectively. The levels of T-SFTSV, F-SFTSV and U-SFTSV were positively correlated with the load of SFTSV in blood. We firstly revealed that SFTSV positive rate of throat swabs were correlated with occurrence of pneumonia and case fatality rate of patients (P < 0.0001). Specific precaution measures were applied by healthcare workers in participating cardiopulmonary resuscitation and orotracheal intubation for severely ill patients with positive T-SFTSV, no event of SFTSV human-to-human transmission occurred after application of effective PPEs. Conclusions: Our research demonstrated SFTSV could shed out from blood, oropharynx, feces and urine in severely ill patients. The excretion of SFTSV from these parts was positively correlated with viral load in the blood. Effective prevention measures against SFTSV human-to-human transmission are needed.

A Case of Brucellosis Concomitant with Severe Fever with Thrombocytopenia Syndrome - Weifang City, Shandong Province, China, 2023.

What is already known about this topic?: Brucellosis and severe fever with thrombocytopenia syndrome (SFTS) are neglected zoonoses, attributable respectively to Brucella and the SFTS virus (SFTSV). While the incidence of these diseases has been rising, instances of co-infection remain uncommon. What is added by this report?: This represents the first documented case of a rare coinfection involving Brucella and SFTSV. We carried out an epidemiological analysis of patients diagnosed with brucellosis and those with SFTS at Yidu Central Hospital of Weifang. Our findings demonstrate a temporal and spatial overlap among the affected individuals. What are the implications for public health practice?: Our findings suggest that co-infections arising from the spatiotemporal overlap of Brucella and SFTSV are plausible, necessitating heightened awareness and enhanced diagnostic measures.

Global epidemiology of severe fever with thrombocytopenia syndrome virus in human and animals: a systematic review and meta-analysis.

Background: Since the initial identification of the Severe Fever with Thrombocytopenia Syndrome (SFTS) in ticks in rural areas of China in 2009, the virus has been increasingly isolated from a diverse array of hosts globally, exhibiting a rising trend in incidence. This study aims to conduct a systematic analysis of the temporal and spatial distribution of SFTS cases, alongside an examination of the infection rates across various hosts, with the objective of addressing public concerns regarding the spread and impact of the disease. Methods: In this systematic review and meta-analysis, an exhaustive search was conducted across multiple databases, including PubMed, Web of Science, Embase, and Medline, CNKI, WanFang, and CQVIP. The literature search was confined to publications released between January 1, 2009, and May 29, 2023. The study focused on collating data pertaining to animal infections under natural conditions and human infection cases reported. Additionally, species names were unified using the National Center for Biotechnology Information (NCBI) database. The notification rate, notification death rate, case fatality rate, and infection rates (or MIR) were assessed for each study with available data. The proportions were pooled using a generalized linear mixed-effects model (GLMM). Meta-regressions were conducted for subgroup analysis. This research has been duly registered with PROSPERO, bearing the registration number CRD42023431010. Findings: We identified 5492 studies from database searches and assessed 238 full-text studies for eligibility, of which 234 studies were included in the meta-analysis. For human infection data, the overall pooled notification rate was 18.93 (95% CI 17.02-21.05) per ten million people, the overall pooled notification deaths rate was 3.49 (95% CI 2.97-4.10) per ten million people, and the overall pooled case fatality rate was 7.80% (95% CI 7.01%-8.69%). There was an increasing trend in notification rate and deaths rate, while the case fatality rate showed a significant decrease globally. Regarding animal infection data, among 94 species tested, 48 species were found to carry positive nucleic acid or antibodies. Out of these, 14 species were classified under Arthropoda, while 34 species fell under Chordata, comprising 27 Mammalia and 7 Aves. Interpretation: This systematic review and meta-analysis present the latest global report on SFTS. In terms of human infections, notification rates and notification deaths rates are on the rise, while the case fatality rate has significantly decreased. More SFTSV animal hosts have been discovered than before, particularly among birds, indicating a potentially broader transmission range for SFTSV. These findings provide crucial insights for the prevention and control of SFTS on a global scale. Funding: None.

Red Blood Cell Distribution Width Predicts Mortality in Hospitalized Patients with Severe Fever with Thrombocytopenia Syndrome.

Background: Severe fever with thrombocytopenia syndrome (SFTS) is an emerging epidemic infectious disease with high mortality rate. This study aimed to investigate the association of red blood cell distribution width (RDW) and mortality risk in hospitalized SFTS patients. Methods: Clinical data of SFTS patients was retrospectively collected from three hospitals between October 2010 and August 2022. Cox proportional hazards model was used to identity the risk factors for fatal outcome. The predictive value of RDW for fatal outcome was evaluated by the receiver operating characteristic (ROC) analysis and Kaplan-Meier methods. Results: Of 292 patients, the median age was 61.5 years. Non-survivors showed higher RDW value than survivors (13.6% vs.13.0%, P < 0.001). The mortality rate was 44.8% in patients with elevated RDW compared to 18.4% of patients with normal RDW, with a relative risk (RR) of 2.439. Elevated RDW was an independent risk factor of mortality (hazards ratio: 1.167, P = 0.019). Patients with elevated RDW had a higher cumulative mortality than patients with normal RDW. The area under the ROC curve (AUC) of RDW for the prediction of mortality was 0.690 (P < 0.001). Conclusion: Elevated RDW was associated with higher mortality risk for patients hospitalized for SFTS. RDW may be helpful for risk stratification in SFTS patients.

Therapeutic plasma exchange combined with ribavirin to rescue critical SFTS patients.

BACKGROUND: Severe fever with thrombocytopenia syndrome (SFTS) is a zoonotic infectious disease caused by the severe fever with thrombocytopenia syndrome virus (SFTSV). Endemic in East Asia, SFTS is characterized by an exceptionally high mortality rate. Presently, there is no established treatment for SFTS, particularly for patients in critical condition. In this study, we collected and analyzed laboratory and clinical data from 92 critically ill patients with SFTS treated at Weihai Municipal Hospital between 2019 and 2022. We hope that our study will provide some hints for the treatment of critically ill patients with SFTS. METHODS: A total of 92 critically ill patients with SFTS were included in this study. Of these patients, 45 received treatment with therapeutic plasma exchange (TPE) and ribavirin (referred to as the TPE group), while the remaining patients received only ribavirin (referred to as the non-TPE group). Clinical and laboratory parameters were analyzed retrospectively. RESULTS: The results showed significant improvements in multiple laboratory parameters following treatment with TPE and ribavirin, including white blood cell and neutrophil count, lactate dehydrogenase, creatine kinase isoenzyme-MB, prothrombin time, activated partial thromboplastin time, D-Dimer, serum sodium and copies of virus genomes. The combination of TPE with ribavirin demonstrated a significant reduction in mortality rates, with a mortality rate of 20.0% in the TPE group compared to 40.4% in the non-TPE group (P = 0.033). CONCLUSIONS: Our findings suggest that critically ill patients with SFTS who received TPE and ribavirin experienced improvements in both clinical and laboratory parameters. These results indicate that TPE combined with ribavirin may represent a promising novel therapeutic approach for managing critically ill patients with SFTS. However, comparative studies of large sample size or randomized clinical trials are warranted to confirm the effectiveness of this combination therapy in the treatment of severe SFTS cases.

Cytokines and lymphocyte subsets are associated with disease severity of severe fever with thrombocytopenia syndrome.

BACKGROUND: Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease caused by severe fever with thrombocytopenia syndrome virus (SFTSV). Previous studies have indicated that SFTS patients have a high mortality rate, which may be related to cytokine storm and immune dysfunction. In our study, we analyzed differences in cytokines and lymphocyte subsets between severe and non-severe SFTS patients, with the aim of identifying predictors of severity. METHODS: We retrospectively analyzed demographic characteristics, clinical data, cytokine profiles, and lymphocyte subsets from 96 laboratory confirmed SFTS patients between April 2021 and August 2023. RESULTS: A total of 96 SFTS patients were enrolled, with a mean age of 65.05 (± 7.92) years old. According to our grouping criteria, 35 (36.5%) of these patients were classified as severe group, while 61 (63.5%) were classified as non-severe group. Univariate analysis revealed that age, interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-10 (IL-10), interferon-α (IFN-α), CD4 + T cell, and CD8 + T cell counts were risk predictors for the severity of SFTS. Further multivariable logistic regression analysis confirmed age, IL-6 levels, and CD4 + T cell counts as independent predictors of SFTS severity. CONCLUSIONS: Severe SFTS patients may experience cytokine storms and immune dysfunction. Aging, elevated levels of IL-6, and decreased CD4 + T cell count may serve as independent predictors for the severity of SFTS.

Exploring the efficacy of routine antimicrobial therapy in severe fever with thrombocytopenia syndrome: Overlap weighting analysis using a nationwide inpatient database.

BACKGROUND: Severe fever with thrombocytopenia syndrome (SFTS) is an infectious disease that presents a formidable challenge due to the absence of established therapeutic strategies that are explicitly tailored to its management. This study aimed to assess the impact of routine antimicrobial therapy on patients diagnosed with SFTS in Japan. We conducted a comprehensive retrospective cohort analysis using extensive data from a national inpatient database. METHODS: This study scrutinized data from adult patients with SFTS and categorized them based on whether they received antimicrobial treatment within the initial 2 days of hospital admission. A meticulous evaluation was carried out on a range of outcomes, such as in-hospital mortality rates, overall costs associated with hospitalization, and length of hospital stay. Overlap weighting was applied along with multivariate regression models to enhance the reliability of the findings through confounder adjustment. The outcomes showed no significant improvement in the prognosis of patients with SFTS who received routine antimicrobial therapy. The use of antimicrobials did not yield statistically significant improvements in in-hospital mortality rates or other secondary outcomes, suggesting that such therapeutic interventions may not be necessary during the early stages of hospital admission. CONCLUSION: In our study, administration of antimicrobials within 2 days of admission for SFTS did not affect prognosis. The standard use of antimicrobial treatments may be an issue that should be reconsidered.

Activated partial thromboplastin time predicts mortality in patients with severe fever with thrombocytopenia syndrome: A multicenter study in north China.

Background: Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease with high lethality. This study aimed to determine whether prolonged activated partial thromboplastin time (APTT) predicted SFTS mortality. Methods: SFTS patients were enrolled from 6 hospitals in the north China. Subjects were divided into training cohort and 5 externally validation cohorts. The least absolute shrinkage and selection operator Cox regression model was performed to screen potential prognostic factors. Risk factors were analyzed using multivariable regression models. Prognostic models were established by Cox regression and random survival forest (RSF) methods, and evaluated regarding discrimination, validity and clinical benefit. Time-dependent receiver operating characteristic (ROC) curve was used to evaluate the predictive effectiveness of variables. Results: 1332 SFTS cases were included, in which 211 patients died. Six potential prognostic factors were screened, and pulse, breath, APTT and aspartic transaminase (AST) were independently associated with mortality in both training cohort (Yantai, N = 791) and external validation cohort (N = 541). APTT was steadily correlated with the fatality (HR: 1.039-1.144; all P < 0.01) in each five sub-validation cohorts (Dandong, Dalian, Tai'an, Qingdao and Beijing). RSF model with variables of APTT, AST, pulse and breath had considerable prognostic effectiveness, which APTT showed the highest prognostic ability with the area under the curve of 0.848 and 0.787 for 7-day and 14-day survival, respectively. Survival differences were found between high and low levels of APTT for mortality using 50s as the optimal cut-off. Conclusions: SFTS patients have prolonged APTT, which is an independent risk factor for fatality. APTT≥50s was recommended as a biomarker to remind physicians to monitor and treat patients more aggressively to improve clinical prognosis.

Development and validation of the PLNA score to predict cytokine storm in acute-phase SFTS patients: A single-center cohort study.

BACKGROUND: Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease known for its high mortality rate and its correlation with Cytokine Storms (CS). Timely detection of CS is crucial for improving the prognosis of the disease. The objective of this investigation was to develop a model for identifying cytokine storms in the acute phase of SFTS. METHODS: A total of 245 patients diagnosed with SFTS were included in this study between January 2020 and July 2022. Among them, 184 patients were part of the training set, while 61 patients were part of the validation set. Variables identified by LASSO were subsequently included in a multivariate logistic regression analysis to determine independent predictors. Subsequently, a nomogram was then developed to predict the likelihood of CS in SFTS patients. The predictive efficacy and clinical applicability of the nomogram model were further assessed through ROC analysis and the DCA curve. RESULTS: Following LASSO analysis, a total of 11 indicators were included in multivariate logistic regression analysis. The findings indicated that PLT (OR 0.865, P < 0.001), LDH (OR 1.002, P < 0.001), Na+ (OR 1.155, P = 0.005), and ALT (OR 1.019, P < 0.001) serve as independently predictors of CS in the acute phase of SFTS. Furthermore, a nomogram named the PLNA was constructed by integrating these four factors. The PLNA model exhibited favorable predictive accuracy with an AUC of 0.958. Moreover, the PLNA model exhibited excellent clinical applicability in both the training and validation sets, as evidenced by the DCA curve. CONCLUSIONS: The PLNA model, constructed using clinical indicators, can predict the probability of cytokine storm in the acute phase of SFTS patients.

Serologic evidence of human exposure to the severe fever with thrombocytopenia syndrome virus and associated viruses in Kenya.

BACKGROUND: Although the diverse communities of tick-borne viruses (TBVs) have recently been proposed, the threat of infection and exposure to TBVs among humans across Kenya has been poorly understood. OBJECTIVE: Severe fever with thrombocytopenia syndrome virus (SFTSV) is an emerging tick-borne viral agent associated with the epidemic of severe fever with thrombocytopenia syndrome (SFTS) disease in East Asian countries. This study investigated the seroprevalence of SFTSV among humans in Kenya. METHODS: Serum samples were collected from 459 healthy people in Kenya and tested for anti-SFTSV antibodies, which were further confirmed by immunofluorescence assays. Micro neutralization assays were performed to identify neutralising antibodies against SFTSV and SFTSV-related viruses. RESULTS: A high seroprevalence (162/459, 35.3%) of SFTSV was found in the samples from nine of the ten surveyed counties in Kenya, with higher rates in the eastern plateau forelands, semiarid and arid areas, and coastal areas than in the area aside Rift valley. The seropositive rate was slightly higher in women than in men and was significantly higher in the 55-64 age group. Neutralising activity against SFTSV was detected in four samples, resulting in a rate of 0.9%. No cross-neutralising activity against the SFTSV-related Guertu virus and Heartland virus was detected in the anti-SFTSV positive serum samples. CONCLUSION: The results provide serologic evidence of human exposure to SFTSV in Kenya and extend our understanding of SFTSV prevalence from Asia to Africa. The findings suggest an increasing threat of exposure to emerging TBVs and the need to investigate tick viromes in Kenya.

First detection of Bandavirus dabieense in ticks collected from migratory birds in the Republic of Korea.

The causative agent of severe fever with thrombocytopenia syndrome (SFTS) is Bandavirus dabieense, an emerging tick-borne zoonotic pathogen. Migratory birds have often been suggested as potential carriers of ticks that can transmit Bandavirus dabieense; however, their role remains unclear. The Republic of Korea (ROK) holds an important position as a stopover on the East Asian-Australasian Flyway. The present study aimed to investigate the potential involvement of migratory birds in the transmission of the SFTS virus (SFTSV) in the ROK. A total of 4,497 ticks were collected across various regions, including Heuksando and Daecheongdo, in the ROK, from bird migration seasons in 2022 and 2023. Genetic analysis of the SFTSV was performed for 96 ticks collected from 20 different species of migratory birds. Polymerase chain reaction (PCR) fragments of SFTSV were detected in one Haemaphysalis concinna nymph collected from a Black-faced Bunting (Emberiza spodocephala) and one Ixodes turdus nymph collected from an Olive-backed Pipit (Anthus hodgsoni) on Daecheongdo and Heuksando, respectively, during their northward migration in two spring seasons. This finding suggests that migratory birds can be considered as possible carriers and long-distance dispersers of ticks and associated tick-borne diseases. This study highlights the importance of clarifying the role and impact of migratory birds in the rapid expansion of tick-borne diseases, facilitating enhanced preparedness and the development of mitigation measures against emerging SFTS across and beyond East Asia.

Increased cTnI Predicts Early Death in Patients with Severe Fever with Thrombocytopenia: A Multicenter Study in North China.

Background: Myocardial injury is common in severe fever with thrombocytopenia syndrome (SFTS) patients. Currently, research on the prognostic value of cardiac troponin I (cTnI) for predicting the mortality of SFTS patients, especially death within 7 days is limited. Methods: Between May 2011 and October 2022, clinical and laboratory data on admission of consecutive SFTS cases were collected from six medical centres in China. The clinical endpoint was in-hospital all-cause death within seven days. Risk factors of myocardial injury and death were analysed using multivariable regression models. Prognostic models were established using Cox regression and performance of indicators was evaluated in terms of calibration, discrimination. Results: A total of 1379 laboratory-confirmed patients were enrolled, in which 686 subjects were included for analysis. The median age was 66 years, with 48.1% of male. Eighty-seven patients died within seven days and 396 patients diagnosed with myocardial injury during hospitalization. Non-survivors had significant higher levels of cardiac indices than survivors, including cTnI, aspartic transaminase (AST) and lactate dehydrogenase (LDH). Elevated levels of cTnI (HR = 1.058, 95% CI:1.032-1.085), AST (HR = 1.191, 95% CI:1.150-1.234) and LDH (HR = 1.019, 95% CI:1.009-1.029) predicted risk of early in-hospital mortality. cTnI model performed best, with area under curve of 0.850 (0.774-0.926) and concordance index of 0.842, respectively. Statistical differences were found between high and low levels of cTnI for mortality (P<0.001) using 0.35 ng/mL as the optimal cut-off. Conclusion: The risk of early in-hospital death can be predicted by cTnI. Clinical doctors should remind vigilant concerning the elevation of cardiac enzyme as soon as possible.

Fibrinogen-to-prealbumin and C-reactive protein-to-prealbumin ratios as prognostic indicators in severe fever with thrombocytopenia syndrome.

Background: The primary aim of this study is to investigate the correlation between serum levels of fibrinogen-to-prealbumin ratio (FPR) and C-reactive protein-to-prealbumin ratio (CPR) and prognostic outcomes among patients with severe fever with thrombocytopenia syndrome (SFTS). SFTS, characterized by elevated mortality rates, represents a substantial public health challenge as an emerging infectious disease. Methods: The study included 159 patients with SFTS. Clinical and laboratory data were compared between the survival and death groups. Univariate and multivariate logistic regression analysis were utilized to identify independent risk factors for mortality. The predictive efficacy of FPR and CPR was evaluated using receiver operating characteristic (ROC) curve. Survival analysis was conducted using the Kaplan-Meier curve and the log-rank test was employed for comparison. Results: The death group exhibited significantly elevated levels of FPR and CPR compared to the survival group (P < 0.05). Multivariate logistic regression analysis confirmed that both FPR and CPR independently correlated with a poorer prognosis among patients with SFTS. The ROC curve analysis indicated that FPR and CPR had superior predictive capabilities compared to C-reactive protein and fibrinogen. Kaplan-Meier survival analysis demonstrated that patients with SFTS who have FPR > 0.045 (log-rank test; χ2 = 17.370, P < 0.001) or CPR > 0.05 (log-rank test; χ2 = 19.442, P < 0.001) experienced significantly lower survival rates within a 30-day follow-up period. Conclusion: Elevated levels of FPR and CPR serve as distinct risk factors for mortality among patients with SFTS, indicating their potential to predict an unfavorable prognosis in these patients.