Search

The Internet is an important gateway for accessing health-related information, and data generated through web queries have been increasingly used as a complementary source for monitoring and forecasting of infectious diseases and they may partially address the issue of underreporting. In this study, we assessed whether tick-borne encephalitis (TBE)-related Internet search volume may be useful as a complementary tool for TBE surveillance in Italy. Monthly Google Trends (GT) data for TBE-related information were extracted for the period between January 2017 and September 2022, corresponding to the available time series of TBE notifications in Italy. Time series modeling was performed by applying seasonal autoregressive integrated moving average (SARIMA) models with or without GT data. The search terms relative to tick bites reflected best the observed temporal distribution of TBE cases, showing a correlation coefficient of 0.81 (95 % CI: 0.71-0.88). Particularly, both the reported number of TBE cases and GT searches occurred mainly during the summer. The peak of disease notifications coincided with that of Google searches in 4 of 6 years. Once calibrated, SARIMA models with or without GT data were applied to a validation set. Retrospective forecast made by the model with GT data was associated with a lower prediction error and accurately predicted the peak timing. By contrast, the traditional SARIMA model underestimated the actual number of TBE notifications by 65 %. Timeliness, easy availability, low cost and transparency make monitoring of the TBE-related Internet search queries a promising addition to the traditional methods of TBE surveillance in Italy., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2024 The Author(s). Published by Elsevier GmbH.. All rights reserved.)

Tick-borne encephalitis virus (TBEV) is a tick-transmitted flavivirus, which can infect humans and animals, sometimes even with a fatal outcome. Since many decades, TBEV is endemic in southern Germany, while only sporadic occurrence has been noted in northern parts of the country so far. Nevertheless, autochthonous human clinical cases are increasing in the federal state of Lower Saxony in north-western Germany, and several natural foci of TBEV transmission have recently been detected in this federal state. In order to shed more light on the current distribution of TBEV in Lower Saxony, the present study examined blood samples from wild and domestic animals for antibodies against TBEV. Overall, samples from 4,085 animals were tested by ELISA, including wild boar (N = 1,208), roe deer (N = 149), red deer (N = 61), fallow deer (N = 18), red foxes (N = 9), nutria (N = 9), raccoon dogs (N = 3), raccoons (N = 3), badgers (N = 1), European pine martens (N = 1), horses (N = 574), sheep (N = 266), goats (N = 67), dogs (N = 1,317) and cats (N = 399). Samples with an ELISA result of ≥60 Vienna units (VIEU)/ml were subjected to confirmatory serum neutralization tests (SNT). In total, 343 of 4,085 (8.4%) animals tested positive for anti-TBEV-IgG by ELISA, of which 60 samples were confirmed by SNT. Samples of 89 animals showed a cytotoxic effect in the SNT and were excluded from seroprevalence calculation, resulting in an overall seroprevalence of 1.5% (60/3,996). Seroprevalence was higher among wild animals (wild boar: 2.9% [34/1,190], roe deer: 2.7% [4/149], red deer: 1.7% [1/60], fallow deer: 5.6% [1/18]) than among domestic animals (dogs: 1.1% [15/1,317], horses: 0.8% [4/505], sheep: 0.4% [1/266]). No anti-TBEV-antibodies were detected in the other wild animal species as well as goats and cats. A notable clustering of positive samples was observed in districts where TBEV transmission foci have been described. Further clusters in other districts suggest the existence of so far undetected transmission foci, underlining the fact that both wild and domestic animals are useful sentinels for monitoring the spread of TBEV., Competing Interests: Declaration of Competing Interest SP is an employee of Elanco Deutschland GmbH, BS is an employee of Elanco Animal Health. Study data collection and interpretation is completely independent from the company's opinion and the authors declare that there is no conflict with commercial interests. The remaining authors declare that they have no competing interests., (Copyright © 2023. Published by Elsevier GmbH.)

Tick-borne encephalitis (TBE) is an infection caused by the Tick-borne encephalitis virus (TBEv) and it is common in Europe. The virus is predominantly transmitted by ticks, but other non-vectorial modes of transmission are possible. This systematic review synthesises the epidemiological impact of non-vectorial modes of TBEv transmission in Europe. 41 studies were included comprising of 1308 TBE cases. Alimentary (36 studies), handling infected material (3 studies),  blood-borne (1 study), solid organ transplant (1 study) were identified as potential routes of TBEv transmission; however, no evidence of vertical transmission from mother to offspring was reported (2 studies). Consumption of unpasteurised milk/milk products was the most common vehicle of transmission and significantly increased the risk of TBE by three-fold (pooled RR 3.05, 95% CI 1.53 to 6.11; 4 studies). This review also confirms handling infected material, blood-borne and solid organ transplant as potential routes of TBEv transmission. It is important to tracing back to find the vehicle of the viral infection and to promote vaccination as it remains a mainstay for the prevention of TBE., Competing Interests: Declaration of Competing Interest The authors declare no conflicts of interest., (Copyright © 2022 The Authors. Published by Elsevier GmbH.. All rights reserved.)

Health control measures instituted in 2020 to mitigate the COVID-19 pandemic decreased the case numbers of many infectious diseases across Europe. One notable exception was tick-borne encephalitis (TBE). In Austria, Germany, Switzerland, Lithuania, and the Czech Republic, the upturn was significantly higher compared to the average of the three years previously (P<0.05), with increases of 88%, 48%, 51%, 28%, and 18%, respectively. Six countries reported TBE incidences of ≥5 cases/100,000, defined as highly endemic by the World Health Organization (WHO). Possible factors contributing to this surge may include increased participation in outdoor activities in endemic regions and increased tick counts/tick activity. In highly endemic regions, the WHO recommends that vaccination be offered to all age groups, including children., (Copyright © 2022 The Author(s). Published by Elsevier GmbH.. All rights reserved.)

Tick-borne encephalitis (TBE) is a viral infection of the central nervous system (CNS) caused by tick-borne encephalitis virus (TBEV). It might take several clinical courses such as: meningitis, meningoencephalitis or meningoencephalomyelitis. The aim this study was to compare the YKL-40 concentration in cerebrospinal fluid (CSF) of patients with different clinical presentations of TBE and patients with excluded meningitis (control group). The concentration of YKL-40 in CSF was determined using Fujirebio tests (Ghent, Belgium) in 32 patients with TBE: Group I-patients with meningoencephalitis (n = 16); Group II-patients with meningitis (n = 16). The control group (CG) consisted of 17 patients in whom any inflammatory process in central nervous system was excluded. The concentration of YKL-40 was significantly higher in encephalitis group than in the CG after 7 days from the last dose of treatment. The concentration in patients with neuroinflammation had a significantly different concentration of YKL-40 compared to patients from the neuroinflammation control group. The ROC curve analysis indicates that CSF YKL-40 concentration at cut-off 783.87 differentiated TBE patients from CG with 100% specificity and 70% sensitivity and CSF YKL-40 concentration at cut-off 980.11 differentiated meningitis from meningoencephalitis with 87.5% specificity and 62.5% sensitivity. YKL-40 takes part in TBE pathogenesis, its concentration is the highest at the early stage of CNS involvement and decreases in the convalescent period. As YKL-40 was significantly higher in the meningitis than in the meningoencephalitis group, it might be used as biomarker in differentiation of these clinical forms of TBE., (Copyright © 2022. Published by Elsevier GmbH.)

Although travel-related tick-borne encephalitis (TBE) cases have been increasingly registered worldwide, very few published case studies are available to date. The present report describes a travel-related TBE case and provides genotypic characterization of two viral isolates. Laboratory diagnostics were based on complement fixation test and virus isolation. This report is unique because the TBE case was first confirmed by virus isolation from the engorged tick and only later from the patient's blood. Moreover, this case demonstrated a successful prophylaxis performed on day 8 post tick exposure although it is generally recommended that anti-TBEV immunoglobulins should be administered not later than on day 4 after tick bite. Sequences of E protein gene fragments were used to phylogenetically characterize the two isolates. The results demonstrated that both viral isolates belonged to clusteron 3A (Zausaev group) of the Asian lineage of the TBEV Siberian subtype. The synonymous nucleotide substitution, C351 T, was identified in E protein gene fragments of TBEV 88 and TBEV 89, which could have been induced by virus transmission. A few important take-home messages can be gleaned from the reported case. First, travelers should be aware of TBE endemic areas that they plan to visit and be proactive when exposed to Ixodes ticks. Second, medical practitioners should always consider travel history and potential tick exposure of patients. Lastly, engorged Ixodes spp. ticks removed from the patients, who have arrived from endemic areas, should be tested for TBEV even in the absence of TBE clinical signs., (Copyright © 2021 The Authors. Published by Elsevier GmbH.. All rights reserved.)

Tick-borne encephalitis (TBE) is an occupational hazard for forestry workers. We measured knowledge levels, misbeliefs, and vaccination rates in forestry trainees in order to tailor specific measures aimed at reducing occupational TBE incidence. A paper-based survey was performed at a central training site for forestry workers in the state of Baden-Wuerttemberg. The questionnaire contained items regarding vaccination status against tick-borne encephalitis virus (TBEV), self-reported tick-borne diseases, knowledge of and attitudes towards tick-borne disease, and practices in the context of ticks and tick bites. All trainees in the period June-December 2018 were surveyed. Statistical analyses were conducted using Mann-Whitney-Rank sum test and one-way ANOVA tests. Two-hundred-twenty-five trainees participated in the survey. Almost all (>99%) were aware of living in a TBE high-risk area. Eighty-three percent of respondents were vaccinated in line with current recommendations. Seventeen percent had no effective vaccination status. Twenty-seven percent believed that ticks can transmit only TBEV and Borrelia spp. Sixty-two percent knew that TBEV infections can be fatal. Only 8% of respondents use tick repellents and only 17% wear long sleeves and pants. Trainees who graduated from a six and (eight or) nine secondary school (Realschule and Abitur respectively) had more knowledge on ticks and tick-borne disease compared to graduates from a five year school (Hauptschule) (p = 0.002 and p = 0,037 respectively). Overall, the TBE vaccination rate is not high enough in this high-risk occupational group. We identified gaps in knowledge and practices that could have an impact on TBE incidence in this group if addressed. Further epidemiological research is needed on knowledge, attitudes, and practices in different high-risk populations., (Copyright © 2019 Elsevier GmbH. All rights reserved.)

Tick-borne encephalitis (TBE) vaccination recommendations for children residing in high-endemicity countries in Europe vary from universal recommendations to none at all. Such differences may result in uncertainty about the value of such prevention among public health authorities, healthcare professionals and parents. We conducted a systematic review of publications and data from the European Centres for Disease Prevention and Control focusing on the epidemiology, clinical characteristics, and outcomes of TBE in a pediatric population. TBE can affect children of any age, occasionally even before the first birthday. Overall, the clinical course of disease is milder compared to adults, and there are fewer neurologic sequelae persisting after the infection. However, recent follow-up surveys identified a substantial proportion of children with long-term cognitive impairment subsequent to TBE infection. Fortunately, two vaccines against western TBE are available, and both are effective and safe. It is an overly simplistic perception that TBE is severe in adults and mild in children, and to therefore conclude that vaccination is important mainly in older age groups. Even if TBE infection is less dramatic in pediatric populations, TBE often results in long-standing cognitive damage. Based on guidance from the World Health Organization, authorities in countries with high endemicity should either offer or recommend TBE vaccination to children at 1-3 years of age., (Copyright © 2018 The Author. Published by Elsevier GmbH.. All rights reserved.)

This study investigated the geographical distribution of Ixodes ricinus and prevalence of the tick-borne encephalitis virus (TBEV) in northern Norway. Flagging for questing I. ricinus ticks was performed in areas ranging from Vikna in Nord-Trøndelag County, located 190km south of the Arctic Circle (66.3°N), to Steigen in Nordland County, located 155km north of the Arctic Circle. We found that ticks were abundant in both Vikna (64.5°N) and Brønnøy (65.1°N). Only a few ticks were found at locations ∼66°N, and no ticks were found at several locations up to 67.5°N. Real-time PCR (RT-PCR) analyses of the collected ticks (nymphs and adults) for the presence of TBEV revealed a low prevalence (0.1%) of TBEV among the nymphs collected in Vikna, while a prevalence of 0% to 3% was found among nymphs collected at five locations in Brønnøy. Adult ticks collected in Vikna and Brønnøy had higher rates of TBEV infection (8.6% and 0%-9.0%, respectively) than the nymphs. No evidence of TBEV was found in the few ticks collected further north of Brønnøy. This is the first report of TBEV being detected at locations up to 65.1°N. It remains to be verified whether viable populations of I. ricinus exist at locations north of 66°N. Future studies are warranted to increase our knowledge concerning tick distribution, tick abundance, and tick-borne pathogens in northern Norway., (Copyright © 2017 Elsevier GmbH. All rights reserved.)

Tick-borne encephalitis virus is the etiological agent of a severe human disease transmitted by hard ticks. It occurs in large parts of eastern, central, and western Asia and in Europe with thousands of human cases each year. Here, the discovery of the virus by Soviet scientists in the late 1930s in the Far East is described. The pioneering work involved with this discovery, which resulted in great scientific and epidemiological achievement, was undertaken under the most difficult conditions, and some of the scientists and their technical assistants paid for it with their health and even their lives. This paper briefly outlines the steps on the way that elucidated the basic etiology and eco-epidemiology of the disease, and does not omit that, as one result of the expeditions and the political situation in the former Soviet Union at that time, some scientists were sent to prison., (Copyright © 2017 Elsevier GmbH. All rights reserved.)

The first tick-borne encephalitis (TBE) cases in Kotka, Finland appeared in 2010. Altogether ten human cases have been diagnosed by 2014. Four had long-lasting sequelae. We collected 195 Ixodes ricinus ticks, nine rodents, and eleven shrews from the archipelago of Kotka in 2011. Three Siberian subtype TBE virus (TBEV) strains were isolated from the ticks and three mammals were positive for TBEV antibodies. The archipelago of Kotka is a newly emerged TBE focus of Siberian subtype TBEV circulating notably in I. ricinus. The patients had on average longer hospitalization than reported for the European subtype infection., (Copyright © 2015 Elsevier GmbH. All rights reserved.)

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., (Copyright © 2015 The Authors. Published by Elsevier GmbH.. All rights reserved.)