A case of severe meningitis caused by SFTSV diagnosed with mNGS assistance

A case of severe meningitis caused by SFTSV diagnosed with mNGS assistance | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Case Report A case of severe meningitis caused by SFTSV diagnosed with mNGS assistance Na Bao, Bingqian Zhuo, Jie Yan, Jieping Long, Kundo Zhong, Dongchang Sun, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7961590/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 6 You are reading this latest preprint version Abstract Unexplained fever or headache is a common and complex symptom in clinical practice, posing significant challenges to precise diagnosis. Cases involving central nervous system (CNS) complications are particularly complex, requiring high vigilance and accurate diagnostic tools. This study retrospectively analyzed the diagnosis and treatment process of a 63-year-old male patient who was hospitalized due to persistent headache, dizziness, and unexplained fever. Considering the patient's history of tick bites and laboratory findings of thrombocytopenia and leukopenia, severe fever with thrombocytopenia syndrome (SFTS) was suspected. To determine the etiology, pathogen detection was performed using cerebrospinal fluid metagenomic next-generation sequencing (mNGS) technology. Based on the patient's epidemiological features such as a history of tick bites, clinical presentation, and laboratory findings (thrombocytopenia and leukopenia), metagenomic next-generation sequencing (mNGS) of the patient's cerebrospinal fluid suggested infection with a novel Bunya virus. Treatment with ribavirin led to improvement in the patient's condition. Severe fever with thrombocytopenia syndrome(SFTS) SFTSV Encephalitis Metagenomic next-generation sequencing (mNGS) Cerebrospinal fluid (CSF) Figures Figure 1 Figure 2 Figure 3 1. INTRODUCTION Severe Fever with Thrombocytopenia Syndrome (SFTS) is a novel infectious disease caused by SFTS virus, first discovered in China in 2009, with subsequent cases reported in South Korea and Japan [ 1 – 5 ]. In 2010, the virus was isolated from SFTS patients and classified within the Phlebovirus genus, characterized as a single-stranded negative-sense RNA virus [ 1 – 3 , 6 ]. The virus is commonly transmitted by ticks, with evidence suggesting that domestic animals may serve as amplifying hosts for SFTSV [ 3 – 6 ]. Due to its complex transmission cycle involving ticks, vertebrate animals, and ticks again, it is challenging to control and prevent, and is considered an emerging pathogen of public health importance[ 1 , 4 ]. Central nervous system diseases, such as acute encephalitis, are common complications of SFTS, occurring in approximately 19% of SFTS patients and increasing the risk of mortality [ 2 – 4 ]. Clinical manifestations of SFTS are nonspecific, with key symptoms including high fever, respiratory symptoms, headache, and gastrointestinal symptoms (loss of appetite, nausea, vomiting)[ 1 , 4 – 6 ]. Consequently, SFTS often leads to misdiagnosis or underdiagnosis in clinical settings. Here, we report a case of SFTS with manifestations including encephalitis, pneumonia, gastrointestinal bleeding, and heart failure, ultimately discharged after treatment through various modalities. 2. CASE PRESENTATION 2.1. Clinical features A 63-year-old male patient presented with a persistent headache lasting over 2 months. Three days prior to admission, he visited a local hospital due to discomfort in his neck accompanied by dizziness. Following treatment there, he developed abnormal mental and behavioral symptoms one day later, prompting his transfer to our facility. Upon physical examination, the patient's temperature was 37.1°C, blood pressure 151/109 mmHg, respiratory rate 15 breaths/min, and pulse 115 beats/min. He was found to be disoriented, unable to speak, with a stiff neck. Both Babinski reflexes were negative. His heart rhythm was regular, and auscultation revealed coarse breath sounds in both lungs. 2.2. Hematology and urine examination Laboratory hematological examinations revealed that the patient's pro-brain natriuretic peptide level was 359 pg/mL (normal reference range ≤ 133 pg/mL), with a white blood cell count recorded at 4×10 9 /L (normal range being 3.50–9.50×10 9 /L) and a platelet count of 52×10 9 /L (typically expected within 125–350×10 9 /L). The D-dimer quantity measured 4680 µg/L (beyond the normal reference of ≤ 550.0 µg/L), ferritin levels exceeded 2000.0 µg/L (normatively 21.8-274.7 µg/L), aspartate aminotransferase (AST) was found to be 945 U/L (normally 15–40 U/L), alanine aminotransferase (ALT) at 136 U/L (standard range 9–50 U/L), lactate dehydrogenase (LDH) reached 2106 U/L (ordinarily 120–250 U/L), serum procalcitonin stood at 0.38 ng/mL (normal threshold ≤ 0.5 ng/mL), and cardiac troponin I was detected at 0.144 µg/L (usually not exceeding 0.050 µg/L). The erythrocyte sedimentation rate (ESR) was documented as 2 mm/h (typically ≤ 43 mm/h), and tests for serum anti-streptolysin O along with screenings for infections such as hepatitis B, hepatitis C, HIV, and syphilis all returned negative results. Glycated hemoglobin A1c (HbA1c) was measured at 7.8% (normative range 5.0%-8.0%), and curiously restated or incorrectly duplicated with another value of 6.8% (which should ideally fall within 3.6%-6.0%). Markers of inflammation including interleukins IL-1β, IL-6, IL-10 (the repetition of IL-10 seems to be an error in the original text), interferon gamma (IFN-γ), and interferon alpha (IFN-α) all showed marked elevation. Urinalysis indicated the presence of protein (+) and significant blood (+++). The reference range of laboratory inspection results is shown in Table 1 . Table 1 laboratory indicators of the patient Hematology examination Measurements/Measurements Normal Interval WBC 4.0×10 9 /L 3.5–9.5×10 9 /L Lymphocytes 16.40% 20–50% Monocytes 3.70% 3–10% Neutrophils 79.40% 40–75% Eosinophils 0×10 9 /L 0.4–8.0×10 9 /L Basophils 0.5×10 9 /L 0.0–1.0×10 9 /L RBC 4.73×10 12 /L 4.30–5.80×10 12 /L Hemoglobin 338 g/L 316–354 g/L Platelets 52×10 9 /L 125–350×10 9 /L CRP 46.2 mg/L ≤ 10.0 mg/L Nt-probnp 359 pg/ml ≤ 133 pg/ml D-dimer quantification 4680 µg/L ≤ 550.0µg/L 2.3. Imaging results Brain CT scan showed no obvious abnormality. MRI and DWI of the head showed that spotty flair high signal scattered in the semi oval area on both sides and beside the lateral ventricle, with fuzzy boundary, and no edema around the lesion. DWI showed no obvious abnormal high signal. The third ventricle and lateral ventricle were slightly enlarged, the cistern and sulcus were slightly widened, and the midline structure was not displaced. Round cystic signal shadow can be seen in cisterna magna. White matter high signal fazekas1 grade, arachnoid cyst of cisterna magna (Fig. 1 A). Lung CT showed bilateral lung inflammation and a small amount of pleural effusion on both sides (Fig. 1 B). 2.4. Cytological analysis of CSF and blood smear Cerebrospinal fluid (CSF) analysis indicated an intracranial pressure of 100 mmH2O (with the normal range for adults being 70–180 mmH2O) (Table 2 ). The patient's CSF appeared red in color, and the Pandy's test was positive. There was a notable increase in the protein content, lactate, and lactate dehydrogenase (LDH) levels in the CSF. Microscopic examination of the CSF sample showed a low number of nucleated cells, insufficient for precise classification, alongside a large quantity of red blood cells. No bacteria, fungi, or other unusual cells were observed. In Fig. 2 , in the peripheral blood smear, the main cell type is neutrophils. At the same time, the presence of late promyelocytes was also observed, but no other abnormal cells were detected. Table 2 Laboratory cytological analysis of the patient's cerebrospinal fluid Laboratory indicators of CSF Patient Normal interval Pandy test Protein quantity + 142.7 mg/dl - < 45.0 mg/dl Lactic acid 3.7 mmol/L 0.5–1.7 mmol/L Glucose quantity 4.89 mmol/L 2.5–4.5 mmol/L Lactic dehydrogenase 61 U/L 8–32 U/L Chloride 128.4 mmol/L 120–132 mmol/L Microalbumin 591 mg/L ≤ 350 mg/L Red blood cell count 31000 cells/µL Nucleated cell count 5 cells/µL 2.5. Etiological identification The cerebrospinal fluid of the patient was stained with gram, and no bacteria or fungi were found under oil microscope. Cerebrospinal fluid samples were taken and cultured on blood plate and fungal plate, showing no growth of bacteria or fungi. It indicates that bacteria and fungal encephalitis can be preliminarily excluded. Q-mNGS™ of nucleic acids extracted from cerebrospinal fluid ™ Quantitative metagenome high-throughput sequencing was used for comparative analysis. The host index (human resources) of cerebrospinal fluid mNGS was 25104.57, and 16 sequences SFTSV were detected, with a relative abundance of 22%. The patient was finally diagnosed as viral encephalitis caused by the SFTSV. 3. Medication and prognosis The patient had pulmonary infection after admission, and received antiviral therapy by intravenous injection of 0.5g acyclovir every 8 hours and 4.5g Piperacillin/Tazobactam every day. After the symptoms did not improve, acyclovir was changed to Foscarnet sodium and intravenous human immunoglobulin for antiviral treatment, and 1.5mg human interleukin-11(Ⅰ) was added to increase platelets, meropenem combined with tigecycline for anti-infection treatment. During the treatment period, the patient suffered from gout, and was given 8mg metoprolol tablets intravenously every 12 hours, plus linezolid for anti-infection. After more than two months, the patient's symptoms improved and he was discharged (Fig. 3 ). 4. Discussion Fever with thrombocytopenia syndrome (SFTS) is mainly infected by the bite of ticks carrying viruses, and can also be infected by close contact with blood or body fluids of cases [ 3 – 6 ]. It was first discovered in China, and then became popular in Korea, Japan and Thailand [ 7 – 8 ]. The main clinical manifestations include fever, thrombocytopenia and leukopenia. Gastrointestinal symptoms and severe cases often die of multiple organ failure [ 4 – 7 ]. Although meningitis is unlikely to occur in patients with SFTS, acute encephalitis is also one of the common complications of SFTS [ 9 ]. Viral encephalitis has always been a public health problem concerned all over the world, and its clinical symptoms are often similar to those of other nervous systems, so it often leads to a high mortality rate because of the delay in diagnosis. Up to now, 50% of viral encephalitis is still unknown [ 10 ]. The central nervous system caused by SFTS is characterized by headache, confusion and seizures. If it is not diagnosed and treated in time, its mortality rate is as high as 44.7% [ 4 , 9 ]. Because the clinical manifestations of SFTS are nonspecific, laboratory confirmation is necessary [ 4 ]. In the case reported in this paper, cerebrospinal fluid of patients with a new generation of metagenome sequencing (mNGS) indicated a new type of SFTSV infection. And combined with the scab wound on the patient's head, the medical history was asked that there had been a history of insect bites on the head. So it is considered that the patient may be bitten by ticks in the mountains, and the specific symptoms such as high fever and thrombocytopenia of the patient are consistent with meningoencephalitis SFTSV infection. At present, the identification of pathogens in clinical laboratories mainly relies on traditional techniques such as culture, nucleic acid amplification, immunoassay, gene sequencing and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Compared with mNGS, these methods are often cumbersome, time-consuming and less accurate. Moreover, mNGS detection can identify more potential pathogens than traditional direct detection. In recent years, it has been reported that many patients have diagnosed some rare pathogens with the help of mNGS, which enables doctors to diagnose diseases quickly and make effective treatment plans to save patients' lives [ 11 , 13 ]. In this case, SFTSV was detected by mNGS, and the patient was given accurate antiviral treatment in time. Acyclovir was changed to foscarnet sodiumand intravenous immunoglobulin for antiviral treatment. At present, ribavirin is recommended for antiviral therapy in clinic because of its broad spectrum and interfering RNA metabolism. Many studies have shown that ribavirin can inhibit SFTSV replication in vitro and partially in vivo [ 7 ]. However, many clinical studies in China have not observed that ribavirin treatment has obvious effect on improving the clinical outcome of SFTS [ 14 – 15 ]. After 16 days of antiviral treatment, there is no new Bunia virus in cerebrospinal fluid mNGS, and this case is also the first successful case of treating SFTSV with sodium formate. 5.Conclusion Acute encephalopathy/encephalitis in SFTS patients is a less common manifestation of central nervous system involvement and is prone to misdiagnosis, thereby warranting heightened attention. Cerebrospinal fluid (CSF) metagenomic next-generation sequencing (mNGS) demonstrates a remarkable advantage in diagnosing viral encephalitis caused by SFTSV. Declarations Ethics approval and consent to participate This study was supported by the Ethics Committee of Zhejiang People’s Hospital (Ethics Committee Approval of Biomedical Research Involving Humans, Approval No.: 2022JS008) and was carried out in accordance with the ethical standards of the Declaration of Helsinki. Consent for publication Written and informed consent was obtained from the patient for publication of this case report and any accompanying images. Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Funding This work was supported by the Traditional Chinese Medicine Science and Technology Project of Zhejiang Province, China (Grant number 2024ZL253), New Project of Zhejiang Provincial People’s Hospital entitled ‘Construction of Rapid Nucleic Acid Detection Platform for Invasive Fungi’ (Grant number 20211214). Author Contribution Bingqian Zhuo: Writing – original draft. Na Bao: Conceptualization, Writing – original draft. Jie Yan: Data curation. Jieping Long: Data curation. Kundo Zhong: Formal analysis. Dongchang Sun: Visualization. Yumei Ge: Writing – review & editing. Acknowledgements We are grateful to all members of the Microbiological Laboratory Department of Zhejiang Provincial People’s Hospital for their assistance in collecting clinical data for this case. Data Availability Data available on request from the corresponding author. References Fang LQ, Liu K, Li XL, Liang S, Yang Y, Yao HW, et al. Emerging tick-borne infections in mainland China: an increasing public health threat. Lancet Infect Dis. 2015;15(12):1467–79. 10.1016/S1473-3099(15)00177-2 . Wu Y, Gao GF. Severe fever with thrombocytopenia syndrome virus expands its borders. Emerg Microbes Infect. 2013;2(6):e36. 10.1038/emi.2013.36 . Yu XJ. Risk factors for death in severe fever with thrombocytopenia syndrome. Lancet Infect Dis. 2018;18(10):1056–7. 10.1016/S1473-3099(18)30312-8 . Liu Q, He B, Huang SY, Wei F, Zhu XQ. Severe fever with thrombocytopenia syndrome, an emerging tick-borne zoonosis. Lancet Infect Dis. 2014;14(8):763–72. 10.1016/S1473-3099(14)70718-2 . Zhuang L, Sun Y, Cui XM, Tang F, Hu JG, Wang LY, et al. Transmission of severe fever with Thrombocytopenia Syndrome Virus by Haemaphysalis longicornis Ticks, China. Emerg Infect Dis. 2018;24(5):868–71. 10.3201/eid2405.151435 . Niu G, Li J, Liang M, Jiang X, Jiang M, Yin H, et al. Severe fever with thrombocytopenia syndrome virus among domesticated animals, China. Emerg Infect Dis. 2013;19(5):756–63. 10.3201/eid1905.120245 . Saijo M. Pathophysiology of severe fever with thrombocytopenia syndrome and development of specific antiviral therapy. J Infect Chemother. 2018;24(10):773–81. 10.1016/j.jiac.2018.07.009 . Rattanakomol P, Khongwichit S, Linsuwanon P, Lee KH, Vongpunsawad S, Poovorawan Y. Severe fever with Thrombocytopenia Syndrome Virus infection, Thailand,2019–2020. Emerg Infect Dis. 2022;28(12):2572–4. 10.3201/eid2812.221183 . Park SY, Kwon JS, Kim JY, Kim SM, Jang YR, Kim MC, et al. Severe fever with thrombocytopenia syndrome-associated encephalopathy/encephalitis. Clin Microbiol Infect. 2018;24(4):432. .e1-432.e4. Cui N, Liu R, Lu QB, Wang LY, Qin SL, Yang ZD, et al. Severe fever with thrombocytopenia syndrome bunyavirus-related human encephalitis. J Infect. 2015;70(1):52–9. 10.1016/j.jinf.2014.08.001 . Han D, Li Z, Li R, Tan P, Zhang R, Li J. mNGS in clinical microbiology laboratories: on the road to maturity. Crit Rev Microbiol. 2019;45(5–6):668–85. 10.1080/1040841X.2019.1681933 . Zhan L, Huang K, Xia W, Chen J, Wang L, Lu J, et al. The diagnosis of severe fever with Thrombocytopenia Syndrome using Metagenomic next-generation sequencing: case report and literature review. Infect Drug Resist. 2022;15:83–9. 10.2147/IDR.S34599 . Zhu T, Cai QQ, Yu J, Liang XS. Metagenomic next-generation sequencing (mNGS) confirmed a critical case of severe fever with thrombocytopenia syndrome virus(SFTSV). Clin Chem Lab Med. 2021;60(2):e42–5. 10.1515/cclm-2021-0791 . Lu QB, Zhang SY, Cui N, Hu JG, Fan YD, Guo CT, et al. Common adverse events associated with ribavirin therapy for Severe Fever with Thrombocytopenia Syndrome. Antiviral Res. 2015;119:19–22. 10.1016/j.antiviral.2015.04.006 . Liu W, Lu QB, Cui N, Li H, Wang LY, Liu K, et al. Case-fatality ratio and effectiveness of ribavirin therapy among hospitalized patients in china who had severe fever with thrombocytopenia syndrome. Clin Infect Dis. 2013;57(9):1292–9. 10.1093/cid/cit530 . Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Reviewers agreed at journal 22 Dec, 2025 Reviewers invited by journal 18 Dec, 2025 Editor assigned by journal 08 Dec, 2025 Editor invited by journal 17 Nov, 2025 Submission checks completed at journal 14 Nov, 2025 First submitted to journal 14 Nov, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7961590","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":562708185,"identity":"577810c5-5d3a-4a21-9a24-af5ec08561d7","order_by":0,"name":"Na Bao","email":"","orcid":"","institution":"Zhejiang University of Technology","correspondingAuthor":false,"prefix":"","firstName":"Na","middleName":"","lastName":"Bao","suffix":""},{"id":562708186,"identity":"e1eb276c-2f92-49ba-90ea-9cbdf0459f76","order_by":1,"name":"Bingqian Zhuo","email":"","orcid":"","institution":"Zhejiang Provincial People's Hospital (Affiliated People's Hospital), 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10:23:15","extension":"html","order_by":10,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":63014,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7961590/v1/306898498f3a48bb83e29644.html"},{"id":98767637,"identity":"4002a608-6aaf-4275-bb20-3ca95884f1c7","added_by":"auto","created_at":"2025-12-22 10:23:16","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":66698,"visible":true,"origin":"","legend":"\u003cp\u003eCT images of the patient's head and lungs\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7961590/v1/fbfef53aa701409ff823d0db.jpeg"},{"id":98767639,"identity":"d0f9105c-01bf-430f-ae07-6bb8b5e87d3c","added_by":"auto","created_at":"2025-12-22 10:23:16","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":125890,"visible":true,"origin":"","legend":"\u003cp\u003eMicroscopic examination of blood smear\u003c/p\u003e","description":"","filename":"floatimage2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7961590/v1/f777fa3de6f6f7edd51d25d1.jpeg"},{"id":98767628,"identity":"a442fbb1-0d2b-4c33-b4b1-8093cbb929c0","added_by":"auto","created_at":"2025-12-22 10:23:16","extension":"jpeg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":217882,"visible":true,"origin":"","legend":"\u003cp\u003eThe clinical timelines of the patient\u003c/p\u003e","description":"","filename":"floatimage3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7961590/v1/5a81599fae861938bfe0afbc.jpeg"},{"id":98783623,"identity":"a61b5535-1533-4723-8690-2aaf64935fdd","added_by":"auto","created_at":"2025-12-22 12:42:24","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":968531,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7961590/v1/06f0ded8-1691-45c7-85bd-9d68f8e10b9a.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"A case of severe meningitis caused by SFTSV diagnosed with mNGS assistance","fulltext":[{"header":"1. INTRODUCTION","content":"\u003cp\u003eSevere Fever with Thrombocytopenia Syndrome (SFTS) is a novel infectious disease caused by SFTS virus, first discovered in China in 2009, with subsequent cases reported in South Korea and Japan [\u003cspan additionalcitationids=\"CR2 CR3 CR4\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. In 2010, the virus was isolated from SFTS patients and classified within the Phlebovirus genus, characterized as a single-stranded negative-sense RNA virus [\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. The virus is commonly transmitted by ticks, with evidence suggesting that domestic animals may serve as amplifying hosts for SFTSV [\u003cspan additionalcitationids=\"CR4 CR5\" citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Due to its complex transmission cycle involving ticks, vertebrate animals, and ticks again, it is challenging to control and prevent, and is considered an emerging pathogen of public health importance[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Central nervous system diseases, such as acute encephalitis, are common complications of SFTS, occurring in approximately 19% of SFTS patients and increasing the risk of mortality [\u003cspan additionalcitationids=\"CR3\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Clinical manifestations of SFTS are nonspecific, with key symptoms including high fever, respiratory symptoms, headache, and gastrointestinal symptoms (loss of appetite, nausea, vomiting)[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan additionalcitationids=\"CR5\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Consequently, SFTS often leads to misdiagnosis or underdiagnosis in clinical settings. Here, we report a case of SFTS with manifestations including encephalitis, pneumonia, gastrointestinal bleeding, and heart failure, ultimately discharged after treatment through various modalities.\u003c/p\u003e"},{"header":"2. CASE PRESENTATION","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1. Clinical features\u003c/h2\u003e \u003cp\u003eA 63-year-old male patient presented with a persistent headache lasting over 2 months. Three days prior to admission, he visited a local hospital due to discomfort in his neck accompanied by dizziness. Following treatment there, he developed abnormal mental and behavioral symptoms one day later, prompting his transfer to our facility. Upon physical examination, the patient's temperature was 37.1\u0026deg;C, blood pressure 151/109 mmHg, respiratory rate 15 breaths/min, and pulse 115 beats/min. He was found to be disoriented, unable to speak, with a stiff neck. Both Babinski reflexes were negative. His heart rhythm was regular, and auscultation revealed coarse breath sounds in both lungs.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e\u003cb\u003e2.2. Hematology and urine examination\u003c/b\u003e\u003c/h2\u003e \u003cp\u003eLaboratory hematological examinations revealed that the patient's pro-brain natriuretic peptide level was 359 pg/mL (normal reference range\u0026thinsp;\u0026le;\u0026thinsp;133 pg/mL), with a white blood cell count recorded at 4\u0026times;10\u003csup\u003e9\u003c/sup\u003e/L (normal range being 3.50\u0026ndash;9.50\u0026times;10\u003csup\u003e9\u003c/sup\u003e/L) and a platelet count of 52\u0026times;10\u003csup\u003e9\u003c/sup\u003e/L (typically expected within 125\u0026ndash;350\u0026times;10\u003csup\u003e9\u003c/sup\u003e/L). The D-dimer quantity measured 4680 \u0026micro;g/L (beyond the normal reference of \u0026le;\u0026thinsp;550.0 \u0026micro;g/L), ferritin levels exceeded 2000.0 \u0026micro;g/L (normatively 21.8-274.7 \u0026micro;g/L), aspartate aminotransferase (AST) was found to be 945 U/L (normally 15\u0026ndash;40 U/L), alanine aminotransferase (ALT) at 136 U/L (standard range 9\u0026ndash;50 U/L), lactate dehydrogenase (LDH) reached 2106 U/L (ordinarily 120\u0026ndash;250 U/L), serum procalcitonin stood at 0.38 ng/mL (normal threshold\u0026thinsp;\u0026le;\u0026thinsp;0.5 ng/mL), and cardiac troponin I was detected at 0.144 \u0026micro;g/L (usually not exceeding 0.050 \u0026micro;g/L). The erythrocyte sedimentation rate (ESR) was documented as 2 mm/h (typically\u0026thinsp;\u0026le;\u0026thinsp;43 mm/h), and tests for serum anti-streptolysin O along with screenings for infections such as hepatitis B, hepatitis C, HIV, and syphilis all returned negative results. Glycated hemoglobin A1c (HbA1c) was measured at 7.8% (normative range 5.0%-8.0%), and curiously restated or incorrectly duplicated with another value of 6.8% (which should ideally fall within 3.6%-6.0%). Markers of inflammation including interleukins IL-1β, IL-6, IL-10 (the repetition of IL-10 seems to be an error in the original text), interferon gamma (IFN-γ), and interferon alpha (IFN-α) all showed marked elevation. Urinalysis indicated the presence of protein (+) and significant blood (+++). The reference range of laboratory inspection results is shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003elaboratory indicators of the patient\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHematology examination\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMeasurements/Measurements\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNormal Interval\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWBC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.0\u0026times;10\u003csup\u003e9\u003c/sup\u003e /L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.5\u0026ndash;9.5\u0026times;10\u003csup\u003e9\u003c/sup\u003e /L\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLymphocytes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e16.40%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e20\u0026ndash;50%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMonocytes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.70%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3\u0026ndash;10%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNeutrophils\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e79.40%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e40\u0026ndash;75%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEosinophils\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u0026times;10\u003csup\u003e9\u003c/sup\u003e /L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.4\u0026ndash;8.0\u0026times;10\u003csup\u003e9\u003c/sup\u003e /L\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBasophils\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.5\u0026times;10\u003csup\u003e9\u003c/sup\u003e /L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.0\u0026ndash;1.0\u0026times;10\u003csup\u003e9\u003c/sup\u003e /L\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRBC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.73\u0026times;10 \u003csup\u003e12\u003c/sup\u003e /L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.30\u0026ndash;5.80\u0026times;10 \u003csup\u003e12\u003c/sup\u003e /L\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHemoglobin\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e338 g/L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e316\u0026ndash;354 g/L\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePlatelets\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e52\u0026times;10\u003csup\u003e9\u003c/sup\u003e /L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e125\u0026ndash;350\u0026times;10\u003csup\u003e9\u003c/sup\u003e /L\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCRP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e46.2 mg/L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u0026le;\u0026thinsp;10.0 mg/L\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNt-probnp\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e359 pg/ml\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u0026le;\u0026thinsp;133 pg/ml\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eD-dimer quantification\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4680 \u0026micro;g/L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u0026le;\u0026thinsp;550.0\u0026micro;g/L\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3. Imaging results\u003c/h2\u003e \u003cp\u003eBrain CT scan showed no obvious abnormality. MRI and DWI of the head showed that spotty flair high signal scattered in the semi oval area on both sides and beside the lateral ventricle, with fuzzy boundary, and no edema around the lesion. DWI showed no obvious abnormal high signal. The third ventricle and lateral ventricle were slightly enlarged, the cistern and sulcus were slightly widened, and the midline structure was not displaced. Round cystic signal shadow can be seen in cisterna magna. White matter high signal fazekas1 grade, arachnoid cyst of cisterna magna (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eA). Lung CT showed bilateral lung inflammation and a small amount of pleural effusion on both sides (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eB).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.4. Cytological analysis of CSF and blood smear\u003c/h2\u003e \u003cp\u003eCerebrospinal fluid (CSF) analysis indicated an intracranial pressure of 100 mmH2O (with the normal range for adults being 70\u0026ndash;180 mmH2O) (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The patient's CSF appeared red in color, and the Pandy's test was positive. There was a notable increase in the protein content, lactate, and lactate dehydrogenase (LDH) levels in the CSF. Microscopic examination of the CSF sample showed a low number of nucleated cells, insufficient for precise classification, alongside a large quantity of red blood cells. No bacteria, fungi, or other unusual cells were observed. In Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, in the peripheral blood smear, the main cell type is neutrophils. At the same time, the presence of late promyelocytes was also observed, but no other abnormal cells were detected.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eLaboratory cytological analysis of the patient's cerebrospinal fluid\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLaboratory indicators of CSF\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePatient\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNormal interval\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePandy test\u003c/p\u003e \u003cp\u003eProtein quantity\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e+\u003c/p\u003e \u003cp\u003e142.7 mg/dl\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003cp\u003e\u0026lt;\u0026thinsp;45.0 mg/dl\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLactic acid\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.7 mmol/L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.5\u0026ndash;1.7 mmol/L\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGlucose quantity\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.89 mmol/L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.5\u0026ndash;4.5 mmol/L\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLactic dehydrogenase\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e61 U/L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8\u0026ndash;32 U/L\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eChloride\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e128.4 mmol/L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e120\u0026ndash;132 mmol/L\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMicroalbumin\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e591 mg/L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u0026le;\u0026thinsp;350 mg/L\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRed blood cell count\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e31000 cells/\u0026micro;L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNucleated cell count\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5 cells/\u0026micro;L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e2.5. Etiological identification\u003c/h2\u003e \u003cp\u003eThe cerebrospinal fluid of the patient was stained with gram, and no bacteria or fungi were found under oil microscope. Cerebrospinal fluid samples were taken and cultured on blood plate and fungal plate, showing no growth of bacteria or fungi. It indicates that bacteria and fungal encephalitis can be preliminarily excluded. Q-mNGS\u0026trade; of nucleic acids extracted from cerebrospinal fluid \u0026trade; Quantitative metagenome high-throughput sequencing was used for comparative analysis. The host index (human resources) of cerebrospinal fluid mNGS was 25104.57, and 16 sequences SFTSV were detected, with a relative abundance of 22%. The patient was finally diagnosed as viral encephalitis caused by the SFTSV.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Medication and prognosis","content":"\u003cp\u003eThe patient had pulmonary infection after admission, and received antiviral therapy by intravenous injection of 0.5g acyclovir every 8 hours and 4.5g Piperacillin/Tazobactam every day. After the symptoms did not improve, acyclovir was changed to Foscarnet sodium and intravenous human immunoglobulin for antiviral treatment, and 1.5mg human interleukin-11(Ⅰ) was added to increase platelets, meropenem combined with tigecycline for anti-infection treatment. During the treatment period, the patient suffered from gout, and was given 8mg metoprolol tablets intravenously every 12 hours, plus linezolid for anti-infection. After more than two months, the patient's symptoms improved and he was discharged (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eFever with thrombocytopenia syndrome (SFTS) is mainly infected by the bite of ticks carrying viruses, and can also be infected by close contact with blood or body fluids of cases [\u003cspan additionalcitationids=\"CR4 CR5\" citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. It was first discovered in China, and then became popular in Korea, Japan and Thailand [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. The main clinical manifestations include fever, thrombocytopenia and leukopenia. Gastrointestinal symptoms and severe cases often die of multiple organ failure [\u003cspan additionalcitationids=\"CR5 CR6\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Although meningitis is unlikely to occur in patients with SFTS, acute encephalitis is also one of the common complications of SFTS [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Viral encephalitis has always been a public health problem concerned all over the world, and its clinical symptoms are often similar to those of other nervous systems, so it often leads to a high mortality rate because of the delay in diagnosis. Up to now, 50% of viral encephalitis is still unknown [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. The central nervous system caused by SFTS is characterized by headache, confusion and seizures. If it is not diagnosed and treated in time, its mortality rate is as high as 44.7% [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Because the clinical manifestations of SFTS are nonspecific, laboratory confirmation is necessary [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. In the case reported in this paper, cerebrospinal fluid of patients with a new generation of metagenome sequencing (mNGS) indicated a new type of SFTSV infection. And combined with the scab wound on the patient's head, the medical history was asked that there had been a history of insect bites on the head. So it is considered that the patient may be bitten by ticks in the mountains, and the specific symptoms such as high fever and thrombocytopenia of the patient are consistent with meningoencephalitis SFTSV infection. At present, the identification of pathogens in clinical laboratories mainly relies on traditional techniques such as culture, nucleic acid amplification, immunoassay, gene sequencing and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Compared with mNGS, these methods are often cumbersome, time-consuming and less accurate. Moreover, mNGS detection can identify more potential pathogens than traditional direct detection. In recent years, it has been reported that many patients have diagnosed some rare pathogens with the help of mNGS, which enables doctors to diagnose diseases quickly and make effective treatment plans to save patients' lives [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. In this case, SFTSV was detected by mNGS, and the patient was given accurate antiviral treatment in time. Acyclovir was changed to foscarnet sodiumand intravenous immunoglobulin for antiviral treatment. At present, ribavirin is recommended for antiviral therapy in clinic because of its broad spectrum and interfering RNA metabolism. Many studies have shown that ribavirin can inhibit SFTSV replication in vitro and partially in vivo [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. However, many clinical studies in China have not observed that ribavirin treatment has obvious effect on improving the clinical outcome of SFTS [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. After 16 days of antiviral treatment, there is no new Bunia virus in cerebrospinal fluid mNGS, and this case is also the first successful case of treating SFTSV with sodium formate.\u003c/p\u003e"},{"header":"5.Conclusion","content":"\u003cp\u003eAcute encephalopathy/encephalitis in SFTS patients is a less common manifestation of central nervous system involvement and is prone to misdiagnosis, thereby warranting heightened attention. Cerebrospinal fluid (CSF) metagenomic next-generation sequencing (mNGS) demonstrates a remarkable advantage in diagnosing viral encephalitis caused by SFTSV.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eEthics approval and consent to participate\u003c/h2\u003e \u003cp\u003eThis study was supported by the Ethics Committee of Zhejiang People\u0026rsquo;s Hospital (Ethics Committee Approval of Biomedical Research Involving Humans, Approval No.: 2022JS008) and was carried out in accordance with the ethical standards of the Declaration of Helsinki.\u003c/p\u003e \u003c/p\u003e\u003cp\u003e \u003ch2\u003eConsent for publication\u003c/h2\u003e \u003cp\u003e Written and informed consent was obtained from the patient for publication of this case report and any accompanying images.\u003c/p\u003e \u003c/p\u003e\u003cp\u003e \u003ch2\u003eDeclaration of competing interest\u003c/h2\u003e \u003cp\u003eThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e \u003cp\u003eThis work was supported by the Traditional Chinese Medicine Science and Technology Project of Zhejiang Province, China (Grant number 2024ZL253), New Project of Zhejiang Provincial People\u0026rsquo;s Hospital entitled \u0026lsquo;Construction of Rapid Nucleic Acid Detection Platform for Invasive Fungi\u0026rsquo; (Grant number 20211214).\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eBingqian Zhuo: Writing \u0026ndash; original draft. Na Bao: Conceptualization, Writing \u0026ndash; original draft. Jie Yan: Data curation. Jieping Long: Data curation. Kundo Zhong: Formal analysis. Dongchang Sun: Visualization. Yumei Ge: Writing \u0026ndash; review \u0026amp; editing.\u003c/p\u003e\u003ch2\u003eAcknowledgements\u003c/h2\u003e \u003cp\u003eWe are grateful to all members of the Microbiological Laboratory Department of Zhejiang Provincial People\u0026rsquo;s Hospital for their assistance in collecting clinical data for this case.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eData available on request from the corresponding author.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eFang LQ, Liu K, Li XL, Liang S, Yang Y, Yao HW, et al. Emerging tick-borne infections in mainland China: an increasing public health threat. 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Case-fatality ratio and effectiveness of ribavirin therapy among hospitalized patients in china who had severe fever with thrombocytopenia syndrome. Clin Infect Dis. 2013;57(9):1292\u0026ndash;9. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1093/cid/cit530\u003c/span\u003e\u003cspan address=\"10.1093/cid/cit530\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-neurology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"nurl","sideBox":"Learn more about [BMC Neurology](http://bmcneurol.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/nurl","title":"BMC Neurology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Severe fever with thrombocytopenia syndrome(SFTS), SFTSV, Encephalitis, Metagenomic next-generation sequencing (mNGS), Cerebrospinal fluid (CSF)","lastPublishedDoi":"10.21203/rs.3.rs-7961590/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7961590/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eUnexplained fever or headache is a common and complex symptom in clinical practice, posing significant challenges to precise diagnosis. Cases involving central nervous system (CNS) complications are particularly complex, requiring high vigilance and accurate diagnostic tools. This study retrospectively analyzed the diagnosis and treatment process of a 63-year-old male patient who was hospitalized due to persistent headache, dizziness, and unexplained fever. Considering the patient's history of tick bites and laboratory findings of thrombocytopenia and leukopenia, severe fever with thrombocytopenia syndrome (SFTS) was suspected. To determine the etiology, pathogen detection was performed using cerebrospinal fluid metagenomic next-generation sequencing (mNGS) technology. Based on the patient's epidemiological features such as a history of tick bites, clinical presentation, and laboratory findings (thrombocytopenia and leukopenia), metagenomic next-generation sequencing (mNGS) of the patient's cerebrospinal fluid suggested infection with a novel Bunya virus. Treatment with ribavirin led to improvement in the patient's condition.\u003c/p\u003e","manuscriptTitle":"A case of severe meningitis caused by SFTSV diagnosed with mNGS assistance","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-12-22 10:23:02","doi":"10.21203/rs.3.rs-7961590/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"326340249748153084691551049066947569218","date":"2025-12-22T13:32:39+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-12-18T12:08:49+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-12-08T17:57:30+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-11-17T09:59:37+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-11-14T14:44:57+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Neurology","date":"2025-11-14T14:17:54+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-neurology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"nurl","sideBox":"Learn more about [BMC Neurology](http://bmcneurol.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/nurl","title":"BMC Neurology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"15c36fab-148f-4ce2-b381-8f6dcbffcb7a","owner":[],"postedDate":"December 22nd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2025-12-22T10:23:03+00:00","versionOfRecord":[],"versionCreatedAt":"2025-12-22 10:23:02","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7961590","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7961590","identity":"rs-7961590","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}