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The aim of our study was to compare the course of TBE in children and adults. A retrospective analysis of the medical records of 669 patients was performed. The patients were categorized into 2 groups: Group I with 68 children and group II with 601 adults. TBE symptoms in children were milder compared with adults, with meningitis in 97% of cases. In adults, meningoencephalitis and meningoencephalomyelitis made up 49.26% of cases. Nausea and vomiting are more frequent in children, while neurological manifestations are more frequent in adults. There were no differences in CSF pleocytosis at the onset of disease in both groups, while CSF protein concentration was higher in adults. Children treated with corticosteroids over 7 days had higher checkup pleocytosis than pleocytosis at the onset of disease compared with adults. Corticosteroid use prolongs the disease duration but does not influence the development of TBE sequelae. Children had more favourable outcomes than adult patients.

Tick-borne encephalitis (TBE) is one of the most important infectious diseases of the central nervous system in dogs from endemic areas. While in humans survival rate and long-term outcomes are well described, these data are lacking in veterinary literature. The aim of the present paper is to characterize the clinical aspects of TBE and to investigate fatality rate, long-term outcome and the long-term neurological sequelae in a population of dogs infected with TBE. We performed a retrospective analysis of 54 dogs diagnosed with TBE at the veterinary hospital of the University of Zurich between 1999 and 2016. Medical data such as signalment, clinical presentation, results of diagnostic procedures, treatment and outcome were collected and analyzed. Statistical analysis including a cox proportional hazard model using a backward stepwise regression approach was performed. In 62% of the TBE cases unspecific signs were described before the onset of neurological signs, resembling a biphasic appearance that is well known in human TBE. Case fatality rate was 33% and all dogs died within the first 4 months after diagnosis. Long-term neurological sequalae were detected in 17% of the TBE cases. For each day of clinical signs before hospital entry the odds of sequalae increased by a factor of 1.88 (CI 1.04–3.15). Older dogs and dogs presented with seizure activity had an increased hazard risk of death (Hazard ration = 1.2, p = 0.03; and 9.38, p = 0.001, respectively). In conclusion, despite TBE being a life-threatening disease with severe clinical signs, the survival rate in our study was 67%. However, long-term sequalae can be of concern especially in dogs with longer clinical course.

Tick-borne encephalitis virus (TBEV) infection can lead to inflammation of the central nervous system. The disease can be effectively prevented by whole inactivated virus vaccines. Here, we investigated the innate immune profile induced in vitro by the antigen component of the vaccines, inactivated TBEV (I-TBEV), to gain insights into the mechanism of action of the TBE vaccine as compared to the live virus. To this end, we exposed human peripheral blood mononuclear cells (PBMCs) to inactivated and live TBEV and assessed cellular responses by RNA sequencing. Both inactivated and live TBEV significantly induced an interferon-dominated gene signature and an increased RIG-I-like receptor (RLR) expression. Using pathway-specific inhibitors, we assessed the involvement of pattern recognition receptors in the sensing of inactivated or live TBEV. Only RLR pathway inhibition significantly suppressed the downstream cascade induced by I-TBEV, while responses to the replicating virus were impacted by the inhibition of RIG-I-like, as well as Toll-like, receptors. Our results show that inactivated and live TBEV predominantly engaged an interferon response in our in vitro PBMC platform, and indicate RLRs as the main pattern recognition receptors involved in I-TBEV sensing.

Three autochthonous cases of tick-borne encephalitis (TBE) acquired in rural areas of France where Lyme borreliosis, but not TBE, is endemic highlight the emergence of TBE in new areas. For patients with neurologic involvement who have been in regions where Ixodes ticks circulate, clinicians should test for TBE virus and other tickborne viruses.

Background Southern Sweden is endemic for tick-borne encephalitis (TBE), with Stockholm County as one of the high-risk areas. Our aim in this study was to describe cases of vaccine failures and to optimize future vaccination recommendations. Methods Patients with TBE were identified in the notification database at the Department of Communicable Disease Control and Prevention in Stockholm County during 2006–2015. Vaccine failure was defined as TBE despite adherence to the recommended vaccination schedule with at least 2 doses. Clinical data were extracted from medical records. Results A total of 1004 TBE cases were identified, 53 (5%) were defined as vaccine failures. In this latter group, the median age was 62 years (6–83). Forty-three (81%) patients were aged >50 years and 2 were children. Approximately half of the patients had comorbidities, with diseases affecting the immune system accounting for 26% of all cases. Vaccine failures following the third or fourth vaccine dose accounted for 36 (68%) of the patients. Severe and moderate TBE disease affected 81% of the cases. Conclusions To our knowledge, this is the largest documented cohort of TBE vaccine failures. Vaccine failure after 5 TBE vaccine doses is rare. Our data provide rationale for adding an extra priming dose to those aged ≥50 years., This 10-year retrospective study includes 53 patients (median age 62 years, 6-83) with TBE vaccination failure. Forty-four (81%) patients were aged ≥50 years. Based on our data, we propose adding an extra priming dose for individuals aged ≥50 years.

Various animal species have been evaluated in depth for their potential as Tick-borne encephalitis virus (TBEV) sentinel species, although evidence for equine capacity is incomplete. Therefore, a comprehensive cross-sectional stratified serosurvey and PCR analysis of selected horses (n = 301) were performed in TBEV endemic localities in Lithuania. Attached and moving ticks (n = 241) have been collected from aforementioned hosts to evaluate natural infectivity of TBEV vectors (Ixodes spp.) in the recreational environments surrounding equestrian centers. All samples were screened for TBEV IgG and positive samples were confirmed by virus neutralization test (VNT). 113 (37.5%) horses from all counties of Lithuania tested positive for TBEV IgG, revealing age and sex indifferent results of equine seroprevalence that were significantly dependent on pedigree: horses of mixed breed were more susceptible to infection possibly due to their management practices. TBEV prevalence in equine species corresponded to TBEV-confirmed human cases in the precedent year. As much as 3.9% of horses were viraemic with TBEV-RNA with subsequent confirmation of TBEV European subtype. 4/38 of tested tick pools were positive for TBEV-RNA (Minimal infectious rate 1.2%). Several unknown microfoci were revealed during the study indicating areas of extreme risk close to popular human entertainment sites. The study provides important evidence in favor of horses&rsquo, usage as sentinel species, as equines could provide more detailed epidemiological mapping of TBEV, as well as more efficient collection of ticks for surveillance studies.

Tick-borne encephalitis (TBE) is the most common viral tick-borne disease in Europe causing thousands of human infections every year. Available risk maps in Europe are solely based on human incidences, but often underestimate areas with TBE virus circulation as shown by several autochthonous cases detected outside known risk areas. A dataset of more than 1300 georeferenced TBE virus detections in ticks and mammals except for humans was compiled and used to estimate the probability of TBE virus presence in Europe. For this, a random forests model was implemented using temperature- and precipitation-dependent bioclimatic variables of the WorldClim dataset, altitude, as well as land cover of the ESA GlobCover dataset. The highest probabilities of TBE virus presence were identified in Central Europe, in the south of the Nordic countries, and in the Baltic countries. The model performance was evaluated by an out-of-bag error (OOB) of 0.174 and a high area under the curve value (AUC) of 0.905. The TBE virus presence maps may subsequently be used to estimate the risk of TBE virus infections in humans and can support decision-makers to identify TBE risk areas and to encourage people to take appropriate actions against tick bites and TBE virus infections.

The present work describes the construction of the gene encoding the recombinant protein flagG­protE, its synthesis, purification and study. The recombinant flagG­protE protein is a promising molecule for developing a candidate recombinant vaccine against tickborne encephalitis by the ability to bind to monoclonal antibodies (MCA) against native protein E of tick­borne encephalitis virus. The antigenic determinants of two recombinant proteins were studied: protE and flagG­protE using a panel of 8 MCA. The recombinant protein protE comprises the tick­borne encephalitis virus envelope protein and the flagGprotE recombinant protein has an additional flagG domain encoding flagellin G of Salmonella typhi. It was found that the MCA tested revealed epitopes on the recombinant protein protE. This indicates that the investigated recombinant protein has an antigenic structure similar to the antigenic structure of the native tick­borne encephalitis virus protein E. In the study of the recombinant protein flagG­protE by the ability to bind a panel of 8 MCA, only five of them react with epitopes of the tested protein. MCA 4F6, 7F10, and 6B9 did not recognize the corresponding epitope in the recombinant flagG­protE protein, while in the recombinant protein protE, these epitopes were detected successfully. Our data indicate that the antigenic structure of recombinant protE­protein can be changed under the influence of the flagellin domain, which in turn can lead to the unavailability of some antigenic determinants. This fact must be taken into account when constructing recombinant molecules with antigenic properties. Nevertheless, the fundamentally important regions in the region of the fusion peptide and III domain are antigenically present on the surface of the recombinant protein. This should ensure the formation of neutralizing antibodies, and the presence of a complete amino acid sequence of protein E in the recombinant protein induces the formation of a T­cell immune response. The emergence of a new generation of vaccines against tick­borne encephalitis with a higher level of safety and immunogenicity will improve the vaccine prevention of the population from tick­borne encephalitis.

Epilepsia partialis continua (EPC) is a rare entity, first described in 1894 by Koževnikov, as a variant of simple focal motor status epilepticus. EPC is most frequently characterized by motor symptoms, but as recently described, non-motor manifestations may occur, such as somatosensory symptoms or aura continua. EPC in adults has been attributed to various etiologies: infectious, vascular, neoplastic, and metabolic. According to the recent definition, we reported a case of EPC with behavioral symptoms, following a tick-borne encephalitis (TBE) contracted in an endemic area (North Eastern Italy). Patient's symptom was a poorly localized "whole body sensation", which is reported as a condition occurring only in frontal lobe epilepsy. Patient's EEG showed a left frontal predominance of epileptiform discharges. Literature highlighted the importance of the Far-eastern TBE variant as a cause of EPC, since no Western variant TBE cases are reported. In contrast to what was claimed so far, our case demonstrates that not only the Far-eastern TBE variant, but also Western variant TBE is a cause of EPC. Prognosis of EPC depends largely on the underlying etiology, and it is frequently drug-resistant. Our patient was treated with intravenous levetiracetam, with a subsequent clinical recovery and a disappearance of epileptiform discharges. The rapid clinic and electroencephalographic response to levetiracetam confirm that it can be a promising therapeutic option for treatment of EPC.

Introduction The aim of this study was the assessment of neuron‐specific enolase (NSE) and S‐100 concentration in serum and cerebrospinal fluid (CSF) in patients with different clinical forms of tick‐borne encephalitis (TBE). Material and Methods The serum and CFS concentrations of S100B and NSE of 43 patients with TBE were measured with ELISA method using commercial kits: NSE and S100B Elisa Kit (DRG, Germany). Subjects were divided into: Group I—patients with meningoencephalitis (n = 17) and Group II—patients with meningitis (n = 26). None of the patients reported any neurodegenerative disorder that could affect the results of the study. The control group (CG) consisted of 13 patients. These patients were admitted to the hospital because of headache, and the CSF examination excluded inflammatory process. Samples were collected on admission (sample 1) and after treatment (sample 2). Results Neuron‐specific enolase concentration in CSF was higher in group I than in group II (p = 0.0002) and controls (p = 0.04). NSE concentration was higher in the second serum and CSF sample in both groups. S100B concentration did not differ between TBE patients and controls. NSE concentration in serum after 14 days was higher in the sequelae group (34.3 ± 9.7 vs. 16.7 ± 15, p = 0.04). Also, NSE serum sample 2/serum sample 1 ratio was significantly higher in the sequelae group (3.57 ± 0.92 vs. 1.53 ± 1.99, p = 0.04). Receiver Operating Characteristic curve analysis indicated that NSE concentration in serum II differentiates sequelae group from other meningoencephalitis patients (p = 0.0001). S100B serum sample 2/CSF sample 2 ratio was lower in the sequelae group (0.05 ± 0.1 vs. 0.37 ± 0.28, p = 0.02). Conclusions (a) Neurodegeneration process is present in TBE encephalitis. (b) NSE concentration correlates with inflammatory parameters in CSF in TBE. (c) Neurodegeneration is present even after clinical recovery of TBE. (d) NSE could be used in the prediction of TBE course. (e) S‐100 did not differ between TBE patients and controls.

Background The number of notified cases of Tick-Borne Encephalitis (TBE) in Sweden has been increasing the past years despite the increased use of TBE-vaccine not subsidized by the healthcare system. Stockholm County is a high endemic area and an earlier study has shown that low-income households have lower vaccination coverage even when they are at high risk. This paper aims to determine the cost-effectiveness of a publicly funded TBE vaccination program in Stockholm. Methods In three different cohorts with individuals aged 3, 40 or 50 years, long-term costs and health outcomes of an out-of-pocket strategy (53% of the cohort is vaccinated on their own expenses) and a structured vaccination program (full cohort is vaccinated covered by the publicly funded health care system), were estimated using a Markov model. The Markov model predicts the costs and effects in term of Quality-adjusted Life Years (QALYs) over a lifetime horizon using a third-party healthcare payer perspective. The primary results are presented as an incremental cost effectiveness ratio (ICER) indicating the additional cost required to achieve one additional QALY with the structured vaccination program. Results The results show that the structured vaccination program is associated with a gain in QALYs and increased costs compared with an out-of-pocket strategy. The calculated ICERs were 27 761, 99 527 and 160 827 SEK/QALY in cohorts of age 3, 40 and 50, respectively. The sensitivity analyses showed that the results are robust when varying different parameters. Conclusion Given the setting of Stockholm county, this analysis shows a cost per QALY of a free vaccinations program, especially for children of 3 years old, below generally acceptable cost-effectiveness thresholds in Sweden.

Tick-borne encephalitis (TBE) virus, which is usually divided into European, Far Eastern and Siberian subtypes, is a serious public health problem in several European and Asian countries. Vaccination is the most effective measure to prevent TBE; cross-subtype protection elicited by the TBE vaccines is biologically plausible since all TBE virus subtypes are closely related. This manuscript systematically explores available data on the cross-subtype immunogenicity elicited by the currently available Western vaccines based on the European subtype. Completed immunization course of 3 doses of both Western vaccines determined very high seroconversion/seropositivity rates against both Far Eastern and Siberian subtypes among previously flavivirus-naive subjects. All but one study found no statistically significant difference in titers of neutralizing antibodies against strains belonging to homologous and heterologous subtypes. Pooled analysis of randomized controlled trials on head-to-head comparison of immunogenicity of Western and Russian TBE vaccines did not reveal differences in seroconversion rates against Far Eastern isolates in either hemagglutination inhibition (risk ratio = 0.98, p = 0.83) or enzyme-linked immunosorbent (risk ratio = 0.95, p = 0.44) assays after 2 vaccine doses. This suggests that, in regions where a heterogeneous TBE virus population circulates, vaccines based on the European subtype may be used alongside vaccines based on the Far Eastern subtype. Studies on the field effectiveness of TBE vaccines and investigation of vaccination failures, especially in countries where different subtypes co-circulate, will further elucidate TBE vaccination-induced cross-subtype protection.

ispartof: Eurosurveillance vol:21 issue:39 pages:27-28 ispartof: location:Sweden status: published

BackgroundTick-borne encephalitis (TBE) presents an increasing burden in many parts of Europe, Asian Russia, Siberia, Asian former USSR and Far East. Incidence can be considered as one way to express the burden. A more comprehensive measure concerns disability-adjusted life years (DALYs), better characterizing the full burden of TBE. TBE burden in DALYs has not yet been estimated, nor has it been specified by the Global Burden of Disease (GBD) studies.ObjectiveThe purpose of the present study is to estimate the burden of TBE in Slovenia, expressed in DALYs, both from the population and individual perspectives. We discuss the impact of TBE burden on public health and potential strategies to reduce this burden in Slovenia. Methods The burden of TBE is estimated by using the updated DALYs' methodology first introduced in the GBD project. The DALYs. calculations are based on the health outcomes of the natural course of the disease being modelled. Corrections for under-reporting and under-ascertainment are applied. The impact of uncertainty in parameters in the model was assessed using sensitivity analyses.ResultsFrom the population perspective, total DALYs amount to 3,450 (167.8 per 100,000 population), while from the individual perspective they amount to 3.1 per case in 2011. Notably, the consequences of TBE present a larger burden than TBE itself.ConclusionsTBE presents a relatively high burden expressed in DALYs compared with estimates for other infectious diseases from the GBD 2010 study for Slovenia. Raising awareness and increasing vaccination coverage are needed to reduce TBE and its consequences.

Omsk hemorrhagic fever virus (OHFV) and Russian spring–summer encephalitis virus (RSSEV) are tick-borne flaviviruses that have close homology but different pathology and disease outcomes. Previously, we reported that C57BL/6 and BALB/c mice were excellent models to study the pathology and clinical signs of human RSSEV and OHFV infection. In the study described here, we found that RSSEV infection induced robust release of proinflammatory cytokines (IL-1α, IL-1β, IL-6 and TNF-α) and chemokines (MCP-1, MIP-1β, RANTES and KC) in the brain at 9 and 11dpi, together with moderate to low Th1 and Th2 cytokines. In contrast, OHFV infection stimulated an early and prominent induction of IL-1α, TNF-α, IL-12p70, MCP-1, MIP-1α and MIP-1β in the spleen of infected mice. Collectively our data suggest that a differential host response to infection may lead to the alternate disease outcomes seen following OHFV or RSSEV infection.

BACKGROUND: The common tick Ixodes ricinus is the main vector in Europe of the tick-borne encephalitis virus and of several species of the Borrelia burgdorferi sensu lato complex, which are the etiological agents of Lyme borreliosis. The risk to contract bites of I. ricinus is dependent on many factors including the behaviour of both ticks and people. The tick's site of attachment on the human body and the duration of tick attachment may be of clinical importance. Data on I. ricinus ticks, which were found attached to the skin of people, were analysed regarding potentially stage-specific differences in location of attachment sites, duration of tick attachment (= feeding duration), seasonal and geographical distribution of tick infestation in relation to age and gender of the tick-infested hosts. METHODS: During 2008-2009, 1770 tick-bitten persons from Sweden and the Åland Islands removed 2110 I. ricinus ticks. Participants provided information about the date of tick detection and location on their body of each attached tick. Ticks were identified to species and developmental stage. The feeding duration of each nymph and adult female tick was microscopically estimated based on the scutal and the coxal index. RESULTS: In 2008, participants were tick-bitten from mid-May to mid-October and in 2009 from early April to early November. The infestation pattern of the nymphs was bimodal whereas that of the adult female ticks was unimodal with a peak in late summer. Tick attachment site on the human body was associated with stage of the tick and gender of the human host. Site of attachment seemed to influence the duration of tick feeding. Overall, 63% of nymphs and adult female ticks were detected and removed more than 24 hours after attachment. Older persons, compared to younger ones, and men, compared to women, removed "their" ticks after a longer period of tick attachment. CONCLUSIONS: The infestation behaviour of the different tick stages concerning where on the host's body the ticks generally will attach and when such ticks generally will be detected and removed in relation to host age and gender, should be of value for the development of prophylactic methods against tick infestation and to provide relevant advice to people on how to avoid or reduce the risk of tick infestation.

A large majority of Austrian citizens are aware of tick-borne encephalitis (TBE), consequently reflected by a high vaccination rate of 85%. In return, risk assessment and disease mapping on human cases might be hampered due to high and inhomogeneous vaccination rates and travel habitats of humans. The roe deer was used to obtain a starting point for the integral view on the actual risk of TBE in Austria. The roe deer exhibits several attributes which makes it suitable as an indicator species: the roe deer has a restricted home range and it is known to be a heavy tick carrier. Furthermore it sero-converts after infection with TBE, but no outbreak occurs.Sera from 945 roe deer were obtained from all over Austria and screened with IFAT for the antibodies against TBE. Twenty-two positive samples, 2.4%, and 17 samples at the borderline titre of 1:16 were identified. The majority of the positive samples, 70.6%, were located in known TBE areas based on human cases. Further research is needed to confirm or reject new endemic foci of TBE transmission.