Severe Fever with Thrombocytopenia Syndrome, Japan, 2013-2017.

We conducted an epidemiologic study of severe fever with thrombocytopenia syndrome (SFTS) in Japan during 2013-2017. Of 303 cases reported during that period, 133 (44%) were included in this study. The median time between onset of illness and diagnosis of SFTS shortened, from 11.5 to 3.0 days, but the case-fatality rate remained high, at 27%. In 64 patients (48%), a close contact with companion animals was reported within 2 weeks of disease onset. Of these 64 patients, 40 were surveyed further, and we confirmed that 3 had direct contact with body fluids of ill companion animals; 2 had direct contact with the saliva of an ill feral cat or pet dog. These patients reported no history of tick bite, suggesting that ill companion animals might be a source of SFTS virus transmission. Direct contact with the body fluids of ill companion animals should be avoided.

Clinical Score System to Differentiate Severe Fever with Thrombocytopenia Syndrome Patients from Patients with Scrub Typhus or Hemorrhagic Fever with Renal Syndrome in Korea.

BACKGROUND: Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease with high mortality in East Asia. This study aimed to develop, for primary care providers, a prediction score using initial symptoms and basic laboratory blood tests to differentiate between SFTS and other endemic zoonoses in Korea. METHODS: Patients aged ≥ 18 years diagnosed with endemic zoonoses during a 3-year period (between January 2015 and December 2017) were retrospectively enrolled from 4 tertiary university hospitals. A prediction score was built based on multivariate logistic regression analyses. RESULTS: Of 84 patients, 35 with SFTS and 49 with other endemic zoonoses were enrolled. In multivariate logistic regression analysis, independent predictors of SFTS included neurologic symptoms (odds ratio [OR], 12.915; 95% confidence interval [CI], 2.173-76.747), diarrhea (OR, 10.306; 95% CI, 1.588-66.895), leukopenia (< 4,000/mm³) (OR, 19.400; 95% CI, 3.290-114.408), and normal C-reactive protein (< 0.5 mg/dL) (OR, 24.739; 95% CI, 1.812-337.742). We set up a prediction score by assigning one point to each of these four predictors. A score of ≥ 2 had 82.9% sensitivity (95% CI, 71.7%-87.5%) and 95.9% specificity (95% CI, 88.0%-99.2%). The area under the curve of the clinical prediction score was 0.950 (95% CI, 0.903-0.997). CONCLUSION: This study finding suggests a simple and useful scoring system to predict SFTS in patients with endemic zoonoses. We expect this strategic approach to facilitate early differentiation of SFTS from other endemic zoonoses, especially by primary care providers, and to improve the clinical outcomes.

Two clusters of Toscana virus meningo-encephalitis in Livorno Province and Elba Island, July-September 2018.

BACKGROUND: Toscana virus (TOSV) is an arbovirus transmitted to humans by Phlebotomus spp sandflies. It causes aseptic meningitis and meningoencephalitis with marked seasonality. Here we describe the clinical, microbiological and epidemiological features of two clusters of cases occurred in Tuscany in 2018. METHODS: A confirmed case was defined as the detection of anti-TOSV IgM and IgG in serum sample, in presence of typical clinical manifestations. We consulted hospital records of hospitalized patients to collect clinical information and obtained epidemiological information from the local health authority investigation report. We telephonically interviewed patients using a standard questionnaire for a 6 months follow-up. RESULTS: A total of 12 cases of TOSV meningo-encephalitis with onset between 4th of July and 12th of September accessed health care services in the province of Livorno. Eight cases were males with median age 41,5 and four were not resident in the area. Serological investigations confirmed a recent TOSV infection. Eight cases reported visiting Elba Island and four had a possible occupational-related exposure. CONCLUSIONS: This surge of infection emphasizes the need of information campaigns coupled with adequate surveillance and control interventions against TOSV that, among other arboviruses, is a growing issue of concern in Italy.

Development of DNA Aptamers against the Nucleocapsid Protein of Severe Fever with Thrombocytopenia Syndrome Virus for Diagnostic Application: Catalytic Signal Amplification using Replication Protein A-Conjugated Liposomes.

Most prevalent infectious diseases worldwide are caused by mediators such as insects and characterized by high mortality and morbidity, thereby creating a global public health concern. Therefore, a sensitive, selective detection platform for diagnosing diseases in the early stages of infection is needed to prevent disease spread and to protect public health. Here, we developed novel DNA aptamers specific to the nucleocapsid protein (NP) of the severe fever with thrombocytopenia syndrome (SFTS) virus and synthesized ssDNA-binding protein-conjugated liposomes encapsulated with horseradish peroxidase (HRP) for application in a simple and universal platform. This platform achieved highly sensitive detection of the NP by measuring the colorimetric signal following lysis of the HRP encapsulated liposomes, mediated by a mixture of 3,3',5,5'-tetramethylbenzidine and H2O2 solution. The limit of detection was 0.009 ng·mL-1, and NP was successfully detected in diluted human serum with a high recovery rate. Moreover, this method was specific and did not exhibit cross-reactivity among NPs of other virus types. These results demonstrated the efficacy of the proposed method as a highly sensitive, specific, and universal diagnostic tool for potential application in monitoring of the early stages of infectious diseases.

Toscana, West Nile, Usutu and tick-borne encephalitis viruses: external quality assessment for molecular detection of emerging neurotropic viruses in Europe, 2017.

BackgroundNeurotropic arboviruses are increasingly recognised as causative agents of neurological disease in Europe but underdiagnosis is still suspected. Capability for accurate diagnosis is a prerequisite for adequate clinical and public health response.AimTo improve diagnostic capability in EVD-LabNet laboratories, we organised an external quality assessment (EQA) focusing on molecular detection of Toscana (TOSV), Usutu (USUV), West Nile (WNV) and tick-borne encephalitis viruses (TBEV).MethodsSixty-nine laboratories were invited. The EQA panel included two WNV RNA-positive samples (lineages 1 and 2), two TOSV RNA-positive samples (lineages A and B), one TBEV RNA-positive sample (Western subtype), one USUV RNA-positive sample and four negative samples. The EQA focused on overall capability rather than sensitivity of the used techniques. Only detection of one, clinically relevant, concentration per virus species and lineage was assessed.ResultsThe final EQA analysis included 51 laboratories from 35 countries; 44 of these laboratories were from 28 of 31 countries in the European Union/European Economic Area (EU/EEA). USUV diagnostic capability was lowest (28 laboratories in 18 countries), WNV detection capacity was highest (48 laboratories in 32 countries). Twenty-five laboratories were able to test the whole EQA panel, of which only 11 provided completely correct results. The highest scores were observed for WNV and TOSV (92%), followed by TBEV (86%) and USUV (75%).ConclusionWe observed wide variety in extraction methods and RT-PCR tests, showing a profound absence of standardisation across European laboratories. Overall, the results were not satisfactory; capacity and capability need to be improved in 40 laboratories.

Rapid Diagnosis of Tick-Borne Illnesses by Use of One-Step Isothermal Nucleic Acid Amplification and Bio-Optical Sensor Detection.

BACKGROUND: Scrub typhus and severe fever with thrombocytopenia syndrome (SFTS) are the most common tick-borne illnesses in South Korea. Early differentiation of SFTS from scrub typhus in emergency departments is essential but difficult because of their overlapping epidemiology, shared risk factors, and similar clinical manifestations. METHODS: We compared the diagnostic performance of one-step isothermal nucleic acid amplification with bio-optical sensor detection (iNAD) under isothermal conditions, which is rapid (20-30 min), with that of real-time PCR, in patients with a confirmed tick-borne illness. Fifteen patients with confirmed SFTS who provided a total of 15 initial blood samples and 5 follow-up blood samples, and 21 patients with confirmed scrub typhus, were evaluated. RESULTS: The clinical sensitivity of iNAD (100%; 95% CI, 83-100) for SFTS was significantly higher than that of real-time PCR (75%; 95% CI, 51-91; P = 0.047), while its clinical specificity (86%; 95% CI, 65-97) was similar to that of real-time PCR (95%; 95% CI, 77-99; P = 0.61). The clinical sensitivity of iNAD for scrub typhus (100%; 95% CI, 81-100) was significantly higher than that of real-time PCR for scrub typhus (67%; 95% CI, 43-85; P = 0.009), while its clinical specificity (90%; 95% CI, 67-98) was similar to that of real-time PCR (95%; 95% CI, 73-100; P > 0.99). CONCLUSIONS: iNAD is a valuable, rapid method of detecting SFTS virus and Orientia tsutsugamushi with high clinical sensitivity and specificity.

Reactive plasmacytosis mimicking multiple myeloma associated with SFTS virus infection: a report of two cases and literature review.

BACKGROUND: Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease caused by a novel bunyavirus named SFTS virus (SFTSV), which is classified into the genus Phlebovirus and family Phenuiviridae. Reactive plasmacytosis mimicking multiple myeloma is a very rare condition in association with SFTS. Here, we describe two SFTS cases who presented with hyperimmunoglobulinemia, as well as extensive bone marrow and peripheral blood plasmacytosis, which mimicked multiple myeloma (MM). CASE PRESENTATION: We report two cases who presented with fever and blood routine abnormity which were conformed as SFTS eventually. They were performed bone marrow aspiration and were admitted to the department of hematology with a preliminary diagnosis of MM. They all had hyperimmunoglobulinemia, extensive bone marrow and peripheral blood plasma cells, prolonged activated partial thromboplastin time (APTT), elevated hepatic enzyme. The two patients recovered with treatment of doxycycline, human immunoglobulins, plasma transfusion, and other supporting treatments. But case 1 occurred lymphoma 8 months later and died. CONCLUSION: SFTS might be one of differential diagnosis of MM in certain endemic area. We also conclude that SFTSV is a pantropic virus that could injure most tissues and cells of the human body.

Clinical features of fatal severe fever with thrombocytopenia syndrome that is complicated by invasive pulmonary aspergillosis.

INTRODUCTION: Severe fever with thrombocytopenia syndrome (SFTS) has been prevalent in parts of Asia during recent years. However, SFTS with invasive pulmonary aspergillosis (IPA) is rare, and it is important to understand its clinical features. MATERIALS AND METHODS: Total four cases of SFTS with IPA are reviewed and detailing the disease progression, treatment options, and prognosis were summarized and analyzed. RESULTS: The patients with SFTS-associated IPA first presented with fever, gastrointestinal symptoms, thrombocytopenia, leukopenia, and multiple organ failure. After 1-2 weeks, the patients developed mild polypnea and wheezing rales, and quickly developed dyspnea and respiratory failure. Tracheal intubation was usually performed, but did not relieve the intractable airway spasm and pulmonary ventilation failure. Bronchoscopy confirmed that the antifungal treatment was ineffective and the aspergillosis had worsened. All patients died of type 2 respiratory failure caused by continued airway obstruction and spasticity. CONCLUSIONS: Given the high mortality rate in this series, there is a need for increased awareness of SFTS-associated IPA. Additional examinations should be performed in these cases, and early-stage antifungal treatment with organ support may be helpful.

A patient with severe fever with thrombocytopenia syndrome and hemophagocytic lymphohistiocytosis-associated involvement of the central nervous system.

Severe fever with thrombocytopenia syndrome (SFTS), a severe infectious disease caused by novel bunyavirus, SFTS virus (SFTSV), is endemic to China, Korea, and Japan. Most SFTS patients show abnormalities in consciousness. Pathological findings in the central nervous system (CNS) of SFTS patients are not reported. A 53-year-old Japanese man was admitted to Uwajima City Hospital with an 8-day history of fever and diarrhea. Laboratory tests revealed leukopenia, thrombocytopenia, and liver enzyme elevation. He was diagnosed as having severe fever with thrombocytopenia syndrome (SFTS) following detection of the SFTSV genome in his blood. Bone marrow aspiration revealed hemophagocytic lymphohistiocytosis. He suffered progressive CNS disturbance and died on day 13 from onset of first symptoms. The SFTSV genome load in blood and levels of certain cytokines increased over the disease course. Necrotizing lymphadenitis with systemic lymphoid tissues positive for nucleocapsid protein (NP) of SFTSV was revealed by immunohistochemical (IHC) analysis. SFTSV-NP-positive immunoblasts were detected in all organs examined, including the CNS, and in the vascular lumina of each organ. Parenchymal cells of all organs examined were negative for SFTSV-NP on IHC analysis. Microscopic examination of the pons showed focal neuronal cell degeneration with hemosiderin-laden macrophages around extended microvessels with perivascular inflammatory cell infiltration and intravascular fibrin deposition. Autopsy confirmed this patient with SFTS was positive for systemic hemophagocytic lymphohistiocytosis including in the CNS. This patient's neurological abnormalities may have been caused by both functional and organic abnormalities. These novel findings provide important insights into the pathophysiology of SFTS.

[Sandfly fever-a "neglected" disease]. / Sandmückenfieber ­ eine "vernachlässigte" Krankheit.

A 45-year-old woman presented at the outpatient department of a center for tropical diseases with fever, diarrhea, headache, myalgia, malaise, and an itchy papular rash. She had been on holiday with her family for 11 days in a mountain village in northern Cyprus. The place was infested with a lot of small, stinging flies or mosquitoes. She and her family became sick after they returned home. The physical examination was normal apart from the rash on the inside of the extremities. Significantly elevated transaminases and a slightly increased C­reactive protein level were found in the blood examination. Considering the country of travel, the report of the "stinging flies" and the clinical presentation, sandfly fever was also taken into account as a differential diagnosis for the hepatitis. Antibodies to the sandfly fever Sicilian virus (SFSV) were detected. They showed the typical dynamics during the course of the illness and thus "pappataci fever" was diagnosed. The case report and a short review of up-to-date literature is meant encourage consideration of phlebovirus infection as a possible differential diagnosis in travelers or refugees suffering from severe febrile hepatitis and rash or aseptic viral meningitis after their stay in the Mediterranean area.

[Fever in a returning traveler from Tuscany]. / Fièvre au retour de Toscane.

Arbovirus infections are emerging pathogens leading sometimes to severe disease. This virus is transmitted by sandflies in the Mediterranean countries during the summer season. The disease is often asymptomatic but can also cause an influenza-like illness and aseptic meningitis or encephalitis. The treatment is supportive and preventive measures should be taken in order to avoid an infection when travelling to the affected areas. The differential diagnosis of fever in the returning traveler from southern European countries should include Toscana virus.

Le Toscana virus est un arbovirus transmis par les moustiques de la famille des phlébotomes. Il est principalement présent dans les pays du bassin méditerranéen et peut provoquer des infections durant l'été. Dans la majorité des cas, les infections sont asymptomatiques, mais elles peuvent également occasionner un syndrome grippal qui peut se compliquer d'une atteinte du système nerveux central, se traduisant par une méningite ou une encéphalite. Le traitement est symptomatique et seule la prévention des piqûres de moustique permet de diminuer le risque d'infection. Une infection à Toscana virus doit être considérée dans le diagnostic différentiel d'un état fébrile au retour d'un voyage en Europe du Sud.

Detection of Toscana virus from an adult traveler returning to Australia with encephalitis.

Toscana virus (TOSV) is identified in sandflies, animals, and humans around the Mediterranean Sea. TOSV has not been reported in Australia. During investigations of cerebrospinal fluid samples from patients with encephalitis, TOSV genetic sequences were identified in a traveler returning to Australia from Europe. TOSV should be considered, especially during May to October, in travelers to Australia who embarked in countries in and around the Mediterranean Sea and who subsequently present for medical care because of neurological symptoms.

Toscana virus meningo-encephalitis: an important differential diagnosis for elderly travellers returning from Mediterranean countries.

BACKGROUND: Elderly patients have a long list of differentials for causes of acute confusion and altered consciousness levels, including infectious agents. In addition, elderly, retired patients often have more time to travel for tourism, particularly to exotic, warmer locations. Mediterranean countries such as Spain and Italy are popular holiday destinations for British and other tourists, especially during the winter months. However, these warm climates allow insect vectors to proliferate, increasing the risk of exposure to endemic vectorborne viral infections whilst on vacation. Such infections may not be routinely considered by geriatric medical teams. CASE PRESENTATION: An 87-year old gentleman presented with a three-day history of worsening confusion, lethargy, ataxia, and fevers following a trip to Spain, where he may have sustained a sandfly bite. By the time of admission, he had a reduced GCS, was hallucinating, and was incontinent of urine and faeces, though blood pressure and heart rate were normal. He also appeared hyperaesthetic, and found even capillary blood sugar testing extremely painful. He had no history of cognitive defect or other neurological conditions. He had been previously independently active, with frequent trips to Spain where he maintained a holiday home. He probably sustained a sandfly bite during this most recent trip, whilst cleaning out a shed. Acute and convalescent sera demonstrated IgG antibodies to Toscana virus at extremely high titres of ≥1:10,000 by immunofluorescence assay, though no Toscana virus RNA was detectable in these sera by the time of presentation. CONCLUSIONS: Toscana virus should be included in the differential diagnosis of any patients presenting with meningo-encephalitis who have recently returned from a Mediterranean country. Testing for Toscana virus infection is performed by serological testing on acute/convalescent paired sera, and/or a polymerase chain reaction (PCR) assay on blood or cerebrospinal fluid (CSF) if presenting within 5 days of illness onset. Making a diagnosis of Toscana virus meningitis/encephalitis (where no other pathogen is detected) has additional clinical utility in reducing or preventing unnecessary use of antibiotics, as well as reassuring the patient and family that generally, this illness is generally self-limiting and full recovery within a few weeks is expected, as in the case reported here.

A Pediatric Case of Severe Fever with Thrombocytopenia Syndrome in Korea.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease and elderly people living in rural areas have the greatest risk of infection. We report the first pediatric case of SFTS in Korea and the clinical characteristics and disease progression in children. A 10-year-old child from Chonnam province visited the hospital with myalgia and a history of fever over the previous 8 days. Her father noticed a tick on her head and removed it before fever developed. Because the symptoms continued, her father consulted the community health center and SFTS virus was detected both from the tick (Haemaphysalis longicornis) and the patient's blood. On hospitalization, fever and severe myalgia were improved and no gastrointestinal and hemorrhagic symptoms were observed. The patient was successfully treated with a combination of steroids, IVIG, and ribavirin. In this report, a pediatric case of SFTS presents a mild clinical course but close attention must be paid to the screening of children with mild symptoms consisting of SFTS.

Seroprevalence of Severe Fever with Thrombocytopenia Syndrome in Southeastern Korea, 2015.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne disease characterized by fever, thrombocytopenia and diarrhea. SFTS was firstly reported in Korea in 2013 but its seroprevalence in the country has yet to be investigated. Here, we investigate the seroprevalence of SFTS in a Korean population. A cross-sectional study was conducted on patients who had their sera tested for various reasons at a tertiary university hospital on particular days in May 2015. This study was conducted in a tertiary hospital in southeastern Korea. Total antibodies including immunoglobulin G (IgG) and immunoglobulin M (IgM), specific to SFTS virus (SFTSV) in serum samples were detected by a double-antigen sandwich enzyme-linked immunosorbent assay (ELISA). A total of 1,069 serum samples were tested. Median age was 59 years (range 12-96 years), and 51.5% were male. Overall, 22 patients (2.1%) were tested positive for anti-SFTSV antibodies. The SFTS seroprevalence increased significantly with age (P = 0.034). The seropositive rate of rural area was higher than that of urban area (7.7% vs. 1.9%, P = 0.040). Seropositive rates were not significantly different among underlying diseases. None of the antibody-positive patients showed typical symptoms or laboratory findings of SFTS at the time of sample collection. Results of real-time reverse transcription polymerase chain reaction (RT-PCR) were negative for all the seropositive patients. Our study shows 2.1% SFTS seroprevalence among the patients visiting a tertiary hospital in Korea. Seroprevalence is higher in older and rural population.

Severe Fever with Thrombocytopenia Syndrome in Patients Suspected of Having Scrub Typhus.

To determine prevalence of severe fever with thrombocytopenia syndrome in South Korea, we examined serum samples from patients with fever and insect bite history in scrub typhus-endemic areas. During the 2013 scrub typhus season, prevalence of this syndrome among patients suspected of having scrub typhus was high (23.0%), suggesting possible co-infection.

Toscana virus encephalitis following a holiday in Sicily.

We report a case of Toscana virus encephalitis. This emerging pathogen is among the three most common causes of meningoencephalitis in Europe during the warm season, yet remains under-recognised. Doctors should consider Toscana virus infection in patients presenting with neurological symptoms who have a relevant exposure history during the summer months.

Phlebovirus infections in Greece.

Sandfly fever viruses are endemic in the Mediterranean region causing to humans asymptomatic or mild infections to severe neurological syndromes. In order to investigate the epidemiology of phlebovirus infections in Greece, samples from 499 patients with acute febrile illness (50.2% accompanied by neurological symptoms) were tested during 2010-2014 by serological and molecular methods. Phlebovirus infection was detected in 40 (8%) patients, 25 of them presenting acute neurological infection. Most cases were observed in the summer, with a peak in August. Increased number of cases was observed in 2013, and three of them were observed in Athens. Toscana virus lineage C RNA was detected in one encephalitis case, while the serological results showed that most cases were caused by phleboviruses belonging to the sandfly fever Naples virus serocomplex. This study provided the first insight into the epidemiology of phleboviral disease in Greece.

Application of recombinant severe fever with thrombocytopenia syndrome virus nucleocapsid protein for the detection of SFTSV-specific human IgG and IgM antibodies by indirect ELISA.

BACKGROUND: Severe fever with thrombocytopenia syndrome (SFTS) is an emerging disease that was first reported in China in 2011. It is caused by SFTS virus (SFTSV) which is a member of the Phlebovirus genus in the Bunyaviridae family. SFTSV has been classified as a BSL3 pathogen. There is a need to develop safe and affordable serodiagnostic methods for proper clinical management of infected patients. METHODS: The full length nucleocapsid (N) gene of SFTSV Yamaguchi strain was amplified by RT-PCR and cloned to an expression vector pQE30. The recombinant (r) SFTSV-N protein was expressed by using Escherichia coli (E. coli) expression system and purified under native conditions. rSFTSV-N protein based indirect IgG and IgM enzyme linked immunosorbent assay (ELISA) systems were established to detect specific human IgG and IgM antibodies, respectively. One hundred fifteen serum samples from clinically suspected-SFTS patients were used to evaluate the newly established systems and the results were compared with the total antibody detecting sandwich ELISA system. RESULTS: The native form of recombinant (r) SFTSV-N protein was expressed and purified. Application of the rSFTSV-N protein based indirect IgG ELISA to the 115 serum samples showed results that perfectly matched those of the total antibody sandwich ELISA with a sensitivity and specificity of 100 %. The rSFTSV-N protein based indirect IgM ELISA missed 8 positive samples that were detected by the total antibody sandwich ELISA. The sensitivity and specificity of rSFTSV-N-IgM capture ELISA were 90.59 and 100 %, respectively. CONCLUSIONS: The rSFTSV-N protein is highly immunoreactive and a good target for use as an assay antigen in laboratory diagnosis. Its preparation is simpler in comparison with that used for the total antibody sandwich system. Our rSFTSV-N protein-based IgG and IgM ELISA systems have the advantage of distinguishing two types of antibodies and require small volume of serum sample only. They are safe to use for diagnosis of SFTS virus infection and especially fit in large-scale epidemiological investigations.

Heartland virus-associated death in tennessee.

BACKGROUND: Heartland virus (HRTV) is a tick-borne phlebovirus recently described in Missouri that is associated with fever, leukopenia, and thrombocytopenia. The virus has also been detected in Ambylomma americanum ticks. METHODS: Here we report the first fatal case of HRTV disease in an 80-year-old Tennessee resident. He was hospitalized with fever, confusion, leukopenia, and thrombocytopenia and developed multiorgan failure and hemorrhage. A tick-borne illness was suspected and testing for ehrlichiosis was negative. He died on hospital day 15, and autopsy specimens were tested for various pathogens as part of an unexplained death evaluation. RESULTS: HRTV antigens were detected in postmortem spleen and lymph nodes by immunohistochemistry, and HRTV was detected in premortem blood by reverse transcription polymerase chain reaction and by isolation in cell culture. CONCLUSIONS: This case demonstrates that HRTV infection can cause severe disease and death and expands the geographic range of HRTV within the United States.