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Król N, Chitimia-Dobler L, Dobler G, Kiewra D, Czułowska A, Obiegala A, Zajkowska J, Juretzek T, Pfeffer M. Identification of New Microfoci and Genetic Characterization of Tick-Borne Encephalitis Virus Isolates from Eastern Germany and Western Poland. Viruses 2024; 16:637. [PMID: 38675977 PMCID: PMC11055073 DOI: 10.3390/v16040637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 04/09/2024] [Accepted: 04/10/2024] [Indexed: 04/28/2024] Open
Abstract
(1) Background: Tick-borne encephalitis (TBE) is the most important tick-borne viral disease in Eurasia, although effective vaccines are available. Caused by the tick-borne encephalitis virus (TBEV, syn. Orthoflavivirus encephalitidis), in Europe, it is transmitted by ticks like Ixodes ricinus and Dermacentor reticulatus. TBEV circulates in natural foci, making it endemic to specific regions, such as southern Germany and northeastern Poland. Our study aimed to identify new TBEV natural foci and genetically characterize strains in ticks in previously nonendemic areas in Eastern Germany and Western Poland. (2) Methods: Ticks were collected from vegetation in areas reported by TBE patients. After identification, ticks were tested for TBEV in pools of a maximum of 10 specimens using real-time RT-PCR. From the positive TBEV samples, E genes were sequenced. (3) Results: Among 8400 ticks from 19 sites, I. ricinus (n = 4784; 56.9%) was predominant, followed by D. reticulatus (n = 3506; 41.7%), Haemaphysalis concinna (n = 108; 1.3%), and I. frontalis (n = 2; <0.1%). TBEV was detected in 19 pools originating in six sites. The phylogenetic analyses revealed that TBEV strains from Germany and Poland clustered with other German strains, as well as those from Finland and Estonia. (4) Conclusions: Although there are still only a few cases are reported from these areas, people spending much time outdoors should consider TBE vaccination.
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Affiliation(s)
- Nina Król
- Institute of Animal Hygiene and Veterinary Public Health, University of Leipzig, 04103 Leipzig, Germany (M.P.)
- Department of Veterinary and Animal Sciences, University of Copenhagen, 1870 Frederiksberg, Denmark
- Clinical Center for Emerging and Vector-Borne Infections, Odense University Hospital, 5000 Odense, Denmark
| | - Lidia Chitimia-Dobler
- Bundeswehr Institute of Microbiology, 80937 Munich, Germany
- Fraunhofer Institute of Immunology, Infection and Pandemic Research, 80799 Munich, Germany
| | - Gerhard Dobler
- Bundeswehr Institute of Microbiology, 80937 Munich, Germany
- Department of Parasitology, Institute of Biology, University of Hohenheim, 70599 Stuttgart, Germany
- Department of Infectious Diseases and Tropical Medicine, Ludwig-Maximilians-University Munich, 80336 Munich, Germany
| | - Dorota Kiewra
- Department of Microbial Ecology and Acaroentomology, University of Wrocław, 51-148 Wrocław, Poland
| | - Aleksandra Czułowska
- Department of Microbial Ecology and Acaroentomology, University of Wrocław, 51-148 Wrocław, Poland
| | - Anna Obiegala
- Institute of Animal Hygiene and Veterinary Public Health, University of Leipzig, 04103 Leipzig, Germany (M.P.)
| | - Joanna Zajkowska
- Department of Infectious Diseases and Neuroinfections, Medical University in Białystok, 15-089 Białystok, Poland;
| | - Thomas Juretzek
- Center for Laboratory Medicine, Microbiology and Hospital Hygiene, Carl-Thiem-Klinikum Cottbus gGmbH, 03048 Cottbus, Germany
| | - Martin Pfeffer
- Institute of Animal Hygiene and Veterinary Public Health, University of Leipzig, 04103 Leipzig, Germany (M.P.)
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O'Neill X, White A, Gortázar C, Ruiz-Fons F. The Impact of Host Abundance on the Epidemiology of Tick-Borne Infection. Bull Math Biol 2023; 85:30. [PMID: 36892680 PMCID: PMC9998325 DOI: 10.1007/s11538-023-01133-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 02/04/2023] [Indexed: 03/10/2023]
Abstract
Tick-borne diseases are an increasing global public health concern due to an expanding geographical range and increase in abundance of tick-borne infectious agents. A potential explanation for the rising impact of tick-borne diseases is an increase in tick abundance which may be linked to an increase in density of the hosts on which they feed. In this study, we develop a model framework to understand the link between host density, tick demography and tick-borne pathogen epidemiology. Our model links the development of specific tick stages to the specific hosts on which they feed. We show that host community composition and host density have an impact on tick population dynamics and that this has a consequent impact on host and tick epidemiological dynamics. A key result is that our model framework can exhibit variation in host infection prevalence for a fixed density of one host type due to changes in density of other host types that support different tick life stages. Our findings suggest that host community composition may play a crucial role in explaining the variation in prevalence of tick-borne infections in hosts observed in the field.
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Affiliation(s)
- Xander O'Neill
- Maxwell Institute for Mathematical Sciences and Department of Mathematics, Heriot-Watt University, Edinburgh, EH14 4AS, UK. x.o'
| | - Andy White
- Maxwell Institute for Mathematical Sciences and Department of Mathematics, Heriot-Watt University, Edinburgh, EH14 4AS, UK
| | - Christian Gortázar
- SaBio, Instituto de Investigación en Recursos Cinegéticos IREC (UCLM & CSIC), 13005, Ciudad Real, Spain
| | - Francisco Ruiz-Fons
- SaBio, Instituto de Investigación en Recursos Cinegéticos IREC (UCLM & CSIC), 13005, Ciudad Real, Spain
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Esser HJ, Lim SM, de Vries A, Sprong H, Dekker DJ, Pascoe EL, Bakker JW, Suin V, Franz E, Martina BEE, Koenraadt CJM. Continued Circulation of Tick-Borne Encephalitis Virus Variants and Detection of Novel Transmission Foci, the Netherlands. Emerg Infect Dis 2022; 28:2416-2424. [PMID: 36288572 PMCID: PMC9707572 DOI: 10.3201/eid2812.220552] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Tick-borne encephalitis virus (TBEV) is an emerging pathogen that was first detected in ticks and humans in the Netherlands in 2015 (ticks) and 2016 (humans). To learn more about its distribution and prevalence in the Netherlands, we conducted large-scale surveillance in ticks and rodents during August 2018-September 2020. We tested 320 wild rodents and >46,000 ticks from 48 locations considered to be at high risk for TBEV circulation. We found TBEV RNA in 3 rodents (0.9%) and 7 tick pools (minimum infection rate 0.02%) from 5 geographically distinct foci. Phylogenetic analyses indicated that 3 different variants of the TBEV-Eu subtype circulate in the Netherlands, suggesting multiple independent introductions. Combined with recent human cases outside known TBEV hotspots, our data demonstrate that the distribution of TBEV in the Netherlands is more widespread than previously thought.
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Răileanu C, Tauchmann O, Silaghi C. Sympatric occurrence of Ixodes ricinus with Dermacentor reticulatus and Haemaphysalis concinna and the associated tick-borne pathogens near the German Baltic coast. Parasit Vectors 2022; 15:65. [PMID: 35193661 PMCID: PMC8862291 DOI: 10.1186/s13071-022-05173-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 01/21/2022] [Indexed: 01/20/2023] Open
Abstract
Background Ixodid ticks from the Northern Hemisphere have registered a northward expansion in recent years, and Dermacentor reticulatus is such an example in Europe, its expansion being considered a result of climate change alongside other factors. The aim of this study was to identify the composition of questing tick species and the associated pathogens at different sites near the German Baltic coast. Methods Questing ticks were collected monthly at four sites (May–November, 2020), mainly grasslands, and in October and November 2020 at a fifth site. Molecular screening of ticks for pathogens included RT-qPCR for the tick-borne encephalitis virus (TBEV), qPCR for Anaplasma phagocytophilum, PCR for Babesia species and Rickettsia species, and nested PCR for Borrelia species. Results Altogether 1174 questing ticks were collected: 760 Ixodes ricinus, 326 D. reticulatus and 88 Haemaphysalis concinna. The highest activity peak of I. ricinus and D. reticulatus was in May, in June for H. concinna while a second peak was observed only for I. ricinus and D. reticulatus in September and October, respectively. All samples tested negative for TBEV. For A. phagocytophilum, 1.5% of I. ricinus adults tested positive while the minimum infection rate (MIR) in nymphs was 1.3%. This pathogen was found in 0.6% of D. reticulatus. Babesia spp. were detected in I. ricinus (18.2% adults, 2.1% MIR in nymphs) and H. concinna (13.3% adults, 9.7% MIR in nymphs). Borrelia spp. were present only in I. ricinus (49.1% adults, 11.9% MIR in nymphs), while Rickettsia spp. were detected in I. ricinus (14% adults, 8.9% MIR in nymphs) and D. reticulatus (82%). Co-detection of pathogens was observed in 26.6% and 54.8% of positive I. ricinus adults and nymph pools, respectively, while one D. reticulatus tested positive for A. phagocytophilum and Rickettsia spp. The most common co-infection in I. ricinus adults was Babesia microti and Borrelia afzelii (12.3% of positive ticks). Conclusions The results of this study confirm the northern expansion of D. reticulatus and H. concinna in Germany. The detailed data of the infection levels at each location could be useful in assessing the risk of pathogen acquisition following a tick bite. Graphical Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-022-05173-2.
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Affiliation(s)
- Cristian Răileanu
- Institute of Infectology, Friedrich-Loeffler-Institut, Suedufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Oliver Tauchmann
- Institute of Infectology, Friedrich-Loeffler-Institut, Suedufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Cornelia Silaghi
- Institute of Infectology, Friedrich-Loeffler-Institut, Suedufer 10, 17493, Greifswald-Insel Riems, Germany. .,Department of Biology, University of Greifswald, Domstraße 11, 17489, Greifswald, Germany.
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New and Confirmed Foci of Tick-Borne Encephalitis Virus (TBEV) in Northern Germany Determined by TBEV Detection in Ticks. Pathogens 2022; 11:pathogens11020126. [PMID: 35215070 PMCID: PMC8876329 DOI: 10.3390/pathogens11020126] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 01/12/2022] [Accepted: 01/19/2022] [Indexed: 12/30/2022] Open
Abstract
Tick-borne encephalitis (TBE) is a tick-transmitted, virus-induced neurological disease with potentially fatal outcomes in humans and animals. Virus transmission takes places in so-called tick-borne encephalitis virus (TBEV) microfoci, which constitute small areas of sustained virus circulation. In southern Germany, TBEV has been endemic for decades; however, a northward expansion of risk areas, based on disease incidence in the human population, has been observed in recent years. The present study investigated TBEV occurrence in questing ticks at eight locations in the federal state of Lower Saxony, northwestern Germany, chosen due to reported associations with human TBE cases (N = 4) or previous virus detection (N = 4). A total of 20,056 ticks were collected in 2020 and 2021 and tested for TBEV RNA in pools of ten nymphs or five adults by quantitative reverse transcription-PCR (RT-qPCR). Positive results were confirmed by RT amplification of the viral E gene. In total, 18 pools from five different sampling locations were positive for TBEV RNA. One previously unknown transmission focus was detected, while ongoing virus circulation was confirmed at the four further locations. Phylogenetic analysis showed that two different virus strains with different origins circulate in the locations identified as natural foci.
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Reusken C, Baronti C, Mögling R, Papa A, Leitmeyer K, Charrel RN. Toscana, West Nile, Usutu and tick-borne encephalitis viruses: external quality assessment for molecular detection of emerging neurotropic viruses in Europe, 2017. ACTA ACUST UNITED AC 2020; 24. [PMID: 31847946 PMCID: PMC6918591 DOI: 10.2807/1560-7917.es.2019.24.50.1900051] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
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.
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Affiliation(s)
- Chantal Reusken
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands.,Department of Viroscience, Erasmus University Medical Centre, Rotterdam, the Netherlands
| | - Cecile Baronti
- Unite des Virus Emergents (UVE: Aix Marseille Univ, IRD 190, INSERM 1207, IHU Mediterranee Infection), Marseille, France
| | - Ramona Mögling
- Department of Viroscience, Erasmus University Medical Centre, Rotterdam, the Netherlands
| | - Anna Papa
- Department of Microbiology, Medical School, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Katrin Leitmeyer
- European Centre for Disease Prevention and Control (ECDC), Solna, Sweden
| | - Remi N Charrel
- Unite des Virus Emergents (UVE: Aix Marseille Univ, IRD 190, INSERM 1207, IHU Mediterranee Infection), Marseille, France
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Ott D, Ulrich K, Ginsbach P, Öhme R, Bock-Hensley O, Falk U, Teinert M, Lenhard T. Tick-borne encephalitis virus (TBEV) prevalence in field-collected ticks (Ixodes ricinus) and phylogenetic, structural and virulence analysis in a TBE high-risk endemic area in southwestern Germany. Parasit Vectors 2020; 13:303. [PMID: 32527288 PMCID: PMC7291635 DOI: 10.1186/s13071-020-04146-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 05/23/2020] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Tick-borne encephalitis (TBE) is the most common viral CNS infection with incidences much higher than all other virus infections together in many risk areas of central and eastern Europe. The Odenwald Hill region (OWH) in southwestern Germany is classified as a TBE risk region and frequent case numbers but also more severe infections have been reported within the past decade. The objective of the present study was to survey the prevalence of tick-borne encephalitis virus (TBEV) in Ixodes ricinus and to associate TBEV genetic findings with TBE infections in the OWH. METHODS Ticks were collected by the flagging methods supported by a crowdsourcing project implementing the interested public as collectors to cover completely and collect randomly a 3532 km2 area of the OWH TBE risk region. Prevalence of TBEV in I. ricinus was analysed by reversed transcription quantitative real-time PCR. Phylogeographic analysis was performed to classify OWH TBEV isolates within a European network of known TBEV strains. Mutational sequence analysis including 3D modelling of envelope protein pE was performed and based on a clinical database, a spatial association of TBE case frequency and severity was undertaken. RESULTS Using the crowd sourcing approach we could analyse a total of 17,893 ticks. The prevalence of TBEV in I. ricinus in the OWH varied, depending on analysed districts from 0.12% to 0% (mean 0.04%). Calculated minimum infection rate (MIR) was one decimal power higher. All TBEV isolates belonged to the European subtype. Sequence analysis revealed a discontinuous segregation pattern of OWH isolates with two putative different lineages and a spatial association of two isolates with increased TBE case numbers as well as exceptional severe to fatal infection courses. CONCLUSIONS TBEV prevalence within the OWH risk regions is comparatively low which is probably due to our methodological approach and may more likely reflect prevalence of natural TBEV foci. As for other European regions, TBEV genetics show a discontinuous phylogeny indicating among others an association with bird migration. Mutations within the pE gene are associated with more frequent, severe and fatal TBE infections in the OWH risk region.
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Affiliation(s)
- Daniela Ott
- Neuroinfectious Diseases Group, Department of Neurology, University Hospital Heidelberg, University of Heidelberg, Im Neuenheimer Feld 350, 69120 Heidelberg, Germany
| | - Kristina Ulrich
- Institute of Aquaculture, University of Stirling, Stirling, FK9 4LA Scotland, UK
| | | | - Rainer Öhme
- Molecular Biology Laboratory, Landesgesundheitsamt Stuttgart, Nordbahnhofstraße 135, 70191 Stuttgart, Germany
| | - Oswinde Bock-Hensley
- Gesundheitsamt Rhein-Neckarkreis, Kurfürsten-Anlage 38-40, 69115 Heidelberg, Germany
| | - Ulrich Falk
- Gesundheitsamt Odenwaldkreis, Michelstädter Str. 12, 64711 Erbach, Germany
| | - Martina Teinert
- Gesundheitsamt Neckar-Odenwaldkreis, Neckarelzer Str. 7, 74821 Mosbach, Germany
| | - Thorsten Lenhard
- Neuroinfectious Diseases Group, Department of Neurology, University Hospital Heidelberg, University of Heidelberg, Im Neuenheimer Feld 350, 69120 Heidelberg, Germany
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Bilgin Z, Turan N, Cizmecigil UY, Altan E, Esatgil MU, Yilmaz A, Aydin O, Kocazeybek B, Richt JA, Yilmaz H. Investigation of Vector-Borne Viruses in Ticks, Mosquitos, and Ruminants in the Thrace District of Turkey. Vector Borne Zoonotic Dis 2020; 20:670-679. [PMID: 32397953 DOI: 10.1089/vbz.2019.2532] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
There is a considerable increase in vector-borne zoonotic diseases around the world, including Turkey, such as Crimean-Congo hemorrhagic fever (CCHF), tick borne encephalitis (TBE), Rift Valley fever (RVF), and West Nile fever (WNF), causing disease and death in humans and animals and significant economical losses. Hence, the aim of this study was to investigate the presence of CCHF virus (CCHFV) and TBE virus (TBEV) in ticks and RVF virus (RVFV) and WNF virus (WNV) in mosquitos, as well as in sheep and cattle, in the Thrace district of the Marmara region, which borders Bulgaria and Greece. Buffy-coat samples from 86 cattle and 81 sheep, as well as 563 ticks and 7390 mosquitos, were collected and examined by quantitative real-time RT-PCR for the presence of CCHFV, TBEV, RVFV, and WNV. All buffy-coat samples from cattle and sheep were negative for these viruses. Similarly, all tick samples were negative for CCHFV-RNA and TBEV-RNA. Among 245 pools representing 7390 mosquitos, only 1 pool sample was found to be positive for WNV-RNA and was confirmed by sequencing. Phylogenetic analysis revealed that it was WNV lineage-2. No RVFV-RNA was detected in the 245 mosquito pools. In conclusion, results of this study indicate that CCHFV, TBEV, and RVFV are not present in livestock and respective vectors in the Thrace district of Marmara region of Turkey, whereas WNV-RNA was found in mosquitos from this region.
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Affiliation(s)
- Zahide Bilgin
- Department of Parasitology, Veterinary Faculty, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Nuri Turan
- Department of Virology, Veterinary Faculty, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Utku Y Cizmecigil
- Department of Virology, Veterinary Faculty, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Eda Altan
- Department of Virology, Veterinary Faculty, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Meltem Ulutas Esatgil
- Department of Parasitology, Veterinary Faculty, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Aysun Yilmaz
- Department of Virology, Veterinary Faculty, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Ozge Aydin
- Department of Virology, Veterinary Faculty, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Bekir Kocazeybek
- Department of Microbiology, Cerrahpasa Faculty of Medicine, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Juergen A Richt
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA
| | - Huseyin Yilmaz
- Department of Virology, Veterinary Faculty, Istanbul University-Cerrahpasa, Istanbul, Turkey
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Gethmann J, Hoffmann B, Kasbohm E, Süss J, Habedank B, Conraths FJ, Beer M, Klaus C. Research paper on abiotic factors and their influence on Ixodes ricinus activity-observations over a two-year period at several tick collection sites in Germany. Parasitol Res 2020; 119:1455-1466. [PMID: 32219549 PMCID: PMC7184057 DOI: 10.1007/s00436-020-06666-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 03/15/2020] [Indexed: 12/22/2022]
Abstract
Tick-borne diseases are a public health issue. To predict vector tick abundance and activity, it is necessary to understand the driving factors for these variables. In this study, the activity of Ixodes ricinus was investigated in forest and meadow habitats in Germany with a focus on abiotic factors. Ixodes ricinus adults, nymphs and larvae were caught by flagging over a period of 2 years. Microclimatic and weather conditions were recorded at the collection sites. Statistical models were applied to describe correlations between abiotic factors and tick activity in univariable and multivariable analyses. Tick activity was observed in a broad range of air temperature between 3 and 28 °C, and air humidity varied between 35 and 95%. In general, tick activity of nymphs and larvae was higher in forest habitats than that in meadows. With the exception of a single specimen of Dermacentor reticulatus, all ticks were Ixodes ricinus, most of them nymphs (63.2% in 2009 and 75.2% in 2010). For the latter, a negative binomial mixed-effects model fitted best to the observed parameters. The modelling results showed an activity optimum between 20 and 23 °C for air temperature and between 13 and 15 °C for ground temperature. In univariable analyses, the collection site, month, season, ground and air temperature were significant factors for the number of ticks caught and for all life stages. In the multivariable analysis, temperature, season and habitat turned out to be key drivers. Ixodes ricinus positive for RNA of tick-borne encephalitis virus was only found at a single sampling site. The results of this study can be used in risk assessments and to parameterise predictive models.
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Affiliation(s)
- Jörn Gethmann
- Friedrich-Loeffler-Institut, Institute of Epidemiology, Südufer 10, D-17493, Greifswald-Insel Riems, Germany
| | - Bernd Hoffmann
- Friedrich-Loeffler-Institut, Institute of Diagnostic Virology, Südufer 10, D-17493, Greifswald-Insel Riems, Germany
| | - Elisa Kasbohm
- Friedrich-Loeffler-Institut, Institute of Epidemiology, Südufer 10, D-17493, Greifswald-Insel Riems, Germany
- Institute of Mathematics and Computer Science, University of Greifswald, Walther-Rathenau-Str. 47, 17489, Greifswald, Germany
| | - Jochen Süss
- Friedrich-Loeffler-Institut, Institute of Bacterial Infections and Zoonoses, Naumburger Str. 96a, D-07743, Jena, Germany
- Brehm Memorial Center, Dorfstraße 22, 07646, Renthendorf, Germany
| | - Birgit Habedank
- Umweltbundesamt (German Environment Agency), Health Pests and their Control, Corrensplatz 1, 14195, Berlin, Germany
| | - Franz J Conraths
- Friedrich-Loeffler-Institut, Institute of Epidemiology, Südufer 10, D-17493, Greifswald-Insel Riems, Germany
| | - Martin Beer
- Friedrich-Loeffler-Institut, Institute of Diagnostic Virology, Südufer 10, D-17493, Greifswald-Insel Riems, Germany
| | - Christine Klaus
- Friedrich-Loeffler-Institut, Institute of Bacterial Infections and Zoonoses, Naumburger Str. 96a, D-07743, Jena, Germany.
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Smura T, Tonteri E, Jääskeläinen A, von Troil G, Kuivanen S, Huitu O, Kareinen L, Uusitalo J, Uusitalo R, Hannila-Handelberg T, Voutilainen L, Nikkari S, Sironen T, Sane J, Castrén J, Vapalahti O. Recent establishment of tick-borne encephalitis foci with distinct viral lineages in the Helsinki area, Finland. Emerg Microbes Infect 2019; 8:675-683. [PMID: 31084456 PMCID: PMC6522972 DOI: 10.1080/22221751.2019.1612279] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Number of tick-borne encephalitis (TBE) cases has increased and new foci have emerged in Finland during the last decade. We evaluated risk for locally acquired TBE in the capital region inhabited by 1.2 million people. We screened ticks and small mammals from probable places of TBE virus (TBEV) transmission and places without reported circulation. The TBEV positive samples were sequenced and subjected to phylogenetic analysis. Within the study period 2007–2017, there was a clear increase of both all TBE cases and locally acquired cases in the Helsinki area. The surveillance of ticks and small mammals for TBEV confirmed four distinct TBEV foci in the Helsinki area. All detected TBEV strains were of the European subtype. TBEV genome sequences indicated that distinct TBEV lineages circulate in each focus. Molecular clock analysis suggested that the virus lineages were introduced to these foci decades ago. In conclusion, TBE has emerged in the mainland of Helsinki area during the last decade, with at least four distinct virus lineages independently introduced into the region previously. Although the overall annual TBE incidence is below the threshold for recommending general vaccinations, the situation requires further surveillance to detect and prevent possible further emergence of local TBE clusters.
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Affiliation(s)
- Teemu Smura
- a Department of Virology , University of Helsinki , Helsinki , Finland.,b Division of Clinical Microbiology , Helsinki University Hospital Laboratory Services (HUSLAB) , Helsinki , Finland
| | - Elina Tonteri
- c Centers for Military Medicine and Biothreat Preparedness , Helsinki , Finland
| | - Anu Jääskeläinen
- b Division of Clinical Microbiology , Helsinki University Hospital Laboratory Services (HUSLAB) , Helsinki , Finland
| | | | - Suvi Kuivanen
- a Department of Virology , University of Helsinki , Helsinki , Finland
| | - Otso Huitu
- e Natural Resources Institute Finland (Luke) , Helsinki , Finland
| | - Lauri Kareinen
- a Department of Virology , University of Helsinki , Helsinki , Finland
| | - Joni Uusitalo
- a Department of Virology , University of Helsinki , Helsinki , Finland
| | - Ruut Uusitalo
- a Department of Virology , University of Helsinki , Helsinki , Finland.,f Department of Geosciences and Geography , University of Helsinki , Helsinki , Finland.,g Department of Veterinary Biosciences , University of Helsinki , Helsinki , Finland
| | | | - Liina Voutilainen
- c Centers for Military Medicine and Biothreat Preparedness , Helsinki , Finland
| | - Simo Nikkari
- c Centers for Military Medicine and Biothreat Preparedness , Helsinki , Finland
| | - Tarja Sironen
- a Department of Virology , University of Helsinki , Helsinki , Finland
| | - Jussi Sane
- h Department of Health Security, Infectious Disease Control and Vaccinations Unit , National Institute for Health and Welfare , Helsinki , Finland
| | | | - Olli Vapalahti
- a Department of Virology , University of Helsinki , Helsinki , Finland.,b Division of Clinical Microbiology , Helsinki University Hospital Laboratory Services (HUSLAB) , Helsinki , Finland.,g Department of Veterinary Biosciences , University of Helsinki , Helsinki , Finland
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11
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Michelitsch A, Wernike K, Klaus C, Dobler G, Beer M. Exploring the Reservoir Hosts of Tick-Borne Encephalitis Virus. Viruses 2019; 11:E669. [PMID: 31336624 PMCID: PMC6669706 DOI: 10.3390/v11070669] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 07/17/2019] [Accepted: 07/19/2019] [Indexed: 12/20/2022] Open
Abstract
Tick-borne encephalitis virus (TBEV) is an important arbovirus, which is found across large parts of Eurasia and is considered to be a major health risk for humans. Like any other arbovirus, TBEV relies on complex interactions between vectors, reservoir hosts, and the environment for successful virus circulation. Hard ticks are the vectors for TBEV, transmitting the virus to a variety of animals. The importance of these animals in the lifecycle of TBEV is still up for debate. Large woodland animals seem to have a positive influence on virus circulation by providing a food source for adult ticks; birds are suspected to play a role in virus distribution. Bank voles and yellow-necked mice are often referred to as classical virus reservoirs, but this statement lacks strong evidence supporting their highlighted role. Other small mammals (e.g., insectivores) may also play a crucial role in virus transmission, not to mention the absence of any suspected reservoir host for non-European endemic regions. Theories highlighting the importance of the co-feeding transmission route go as far as naming ticks themselves as the true reservoir for TBEV, and mammalian hosts as a mere bridge for transmission. A deeper insight into the virus reservoir could lead to a better understanding of the development of endemic regions. The spatial distribution of TBEV is constricted to certain areas, forming natural foci that can be restricted to sizes of merely 500 square meters. The limiting factors for their occurrence are largely unknown, but a possible influence of reservoir hosts on the distribution pattern of TBE is discussed. This review aims to give an overview of the multiple factors influencing the TBEV transmission cycle, focusing on the role of virus reservoirs, and highlights the questions that are waiting to be further explored.
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Affiliation(s)
- Anna Michelitsch
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Südufer 10, 17493 Greifswald-Insel Riems, Germany
| | - Kerstin Wernike
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Südufer 10, 17493 Greifswald-Insel Riems, Germany
| | - Christine Klaus
- Institute for Bacterial Infections and Zoonoses, Friedrich-Loeffler-Institut, Naumburger Str. 96a, 07743 Jena, Germany
| | - Gerhard Dobler
- Bundeswehr Institute of Microbiology, German Center of Infection Research (DZIF) partner site Munich, Neuherbergstraße 11, 80937 München, Germany
| | - Martin Beer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Südufer 10, 17493 Greifswald-Insel Riems, Germany.
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12
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Casati Pagani S, Frigerio Malossa S, Klaus C, Hoffmann D, Beretta O, Bomio-Pacciorini N, Lazzaro M, Merlani G, Ackermann R, Beuret C. First detection of TBE virus in ticks and sero-reactivity in goats in a non-endemic region in the southern part of Switzerland (Canton of Ticino). Ticks Tick Borne Dis 2019; 10:868-874. [PMID: 31047827 DOI: 10.1016/j.ttbdis.2019.04.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 03/28/2019] [Accepted: 04/10/2019] [Indexed: 10/27/2022]
Abstract
In Switzerland, tick-borne encephalitis (TBE) is a notifiable human disease with an average of 210 cases per year in the last 10 years (2008-2017). A national surveillance conducted in 2009 reported a prevalence of 0.46% for tick-borne encephalitis virus (TBEV) detected in ticks, which is in accordance with the prevalences found in Europe from 0.1%-5%. The Canton of Ticino in the southern part of Switzerland, geographically separated from the rest of the national territory by the Alps, is considered a non-endemic region, as no autochthonous clinical cases and no TBEV presence in ticks have ever been reported. In order to understand the epidemiological situation in Ticino, we conducted a large study investigating the TBEV presence in field-collected Ixodes ricinus ticks and in goat and human sera. Goats and sheep were considered as sentinel hosts showing persistence of antibodies also after 28 months in the absence of symptoms; this longevity supports the data validity to characterize an area with the TBEV status. The goat sera collection was composed of a total of 662 samples from 37 flocks. The total seroprevalence was 14.6%. 39 (40%) of the 97 SNT-positive samples showed an antibody titer ≥ 1:120 which indicates recent infection and consequently the probable presence of active foci among the pastures frequented by the goats belonging to 10 flocks. In total, 51 owners participated in the study and all were TBEV antibody-free. A total of 12'052 I. ricinus ticks (nymphs and adults) were collected and 1'371 pools were tested using quantitative real-time RT-PCR. Only one positive pool was reported with a prevalence of 0.35%. Metagenomic analysis revealed that the TBEV strain isolated from the ticks collected in Ticino is closely related to 2 strains coming from the Canton of Valais (99.1% and 98.7% identity, respectively), a neighbouring region of the Canton of Ticino. These two Cantons are close together but separated by high mountains (Alps) and we hypothesize that infected ticks were transported by wild animals from Valais into the Valle Maggia in Ticino where we found positive ticks. In conclusion, our data show for the first time the presence of TBEV in ticks and the related sero-reactivity in goats, confirming the presence of TBEV in the environment of the Canton of Ticino. Further surveillance studies will have to be conducted to follow the persistence of TBEV in this region.
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Affiliation(s)
- Simona Casati Pagani
- Dipartimento della sanità e della socialità, Ufficio del medico cantonale, Via Dogana 16, 6500, Bellinzona, Switzerland.
| | - Simona Frigerio Malossa
- EOC - Dipartimento di medicina di laboratorio, Servizio di microbiologia (SMIC), Via Mirasole 22a, 6500, Bellinzona, Switzerland
| | - Christine Klaus
- Friedrich-Loeffler-Institut, Institute of Bacterial Infections and Zoonoses, Naumburger Str. 96a, 07743, Jena, Germany
| | - Donata Hoffmann
- Friedrich-Loeffler-Institut, Institute of Diagnostic Virology, Südufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Ottavio Beretta
- Dipartimento della sanità e della socialità, Ufficio del medico cantonale, Via Dogana 16, 6500, Bellinzona, Switzerland
| | - Nicola Bomio-Pacciorini
- Dipartimento del territorio, Ufficio forestale 4° circondario, Via Antonio Ciseri 13, 6600, Locarno, Switzerland
| | - Mario Lazzaro
- Dipartimento della sanità e della socialità, Ufficio del medico cantonale, Via Dogana 16, 6500, Bellinzona, Switzerland
| | - Giorgio Merlani
- Dipartimento della sanità e della socialità, Ufficio del medico cantonale, Via Dogana 16, 6500, Bellinzona, Switzerland
| | - Rahel Ackermann
- National Reference Centre for Tick-Transmitted Diseases (NRZK), Labor Spiez, Ausstrasse, 3700, Spiez, Switzerland
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13
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Yilmaz H, Barut K, Karakullukcu A, Kasapcopur O, Kocazeybek B, Altan E, Cizmecigil UY, Yilmaz A, Bilgin Z, Ulutas Esatgil M, Klaus C, Richt JA, Turan N. Serological Evidence of Tick-Borne Encephalitis and West Nile Virus Infections Among Children with Arthritis in Turkey. Vector Borne Zoonotic Dis 2019; 19:446-449. [PMID: 30688547 DOI: 10.1089/vbz.2018.2349] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Tick-borne encephalitis virus (TBEV) and West Nile virus (WNV) are mainly transmitted by arthropod vectors to vertebrate hosts including humans, resulting in fever and neurological signs. The aim of this study was to investigate the presence of antibodies to TBEV and WNV, and TBEV-RNA and WNV-RNA in Turkish children with fever and/or arthritis. For this purpose, 110 sera and buffy-coat samples were collected; sera were analyzed by indirect enzyme-linked immunosorbent assay for the presence of IgM and IgG antibodies to TBEV and WNV, and buffy-coat-derived white blood cells were analyzed by quantitative real-time RT-PCR for TBEV-RNA and WNV-RNA. IgM antibodies to TBEV were detected in five children between the ages of 3 and 7 years; no IgG antibodies to TBEV were detected. IgG antibodies to WNV were detected in two children and IgM antibodies to WNV were detected in six children, between the ages of 3 and 7 years. One of the children had IgM antibodies to WNV and to TBEV. Children who had antibodies to TBEV and WNV had fever and/or arthritis but no obvious neurological signs. Molecular diagnostic approaches revealed that neither TBEV-RNA nor WNV-RNA was present in any of the buffy-coat samples, not even in children with IgM-specific antibodies. Our serological results indicate that children in Turkey are exposed to TBEV and WNV.
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Affiliation(s)
- Huseyin Yilmaz
- 1 Department of Virology, Veterinary Faculty, Istanbul University-Cerrahpasa, Avcilar, Istanbul, Turkey
| | - Kenan Barut
- 2 Department of Child Health and Diseases, Cerrahpasa Medical School, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Asiye Karakullukcu
- 3 Department of Microbiology, Cerrahpasa Faculty of Medicine, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Ozgur Kasapcopur
- 2 Department of Child Health and Diseases, Cerrahpasa Medical School, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Bekir Kocazeybek
- 3 Department of Microbiology, Cerrahpasa Faculty of Medicine, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Eda Altan
- 1 Department of Virology, Veterinary Faculty, Istanbul University-Cerrahpasa, Avcilar, Istanbul, Turkey
| | - Utku Y Cizmecigil
- 1 Department of Virology, Veterinary Faculty, Istanbul University-Cerrahpasa, Avcilar, Istanbul, Turkey
| | - Aysun Yilmaz
- 1 Department of Virology, Veterinary Faculty, Istanbul University-Cerrahpasa, Avcilar, Istanbul, Turkey
| | - Zahide Bilgin
- 4 Department of Parasitology, Veterinary Faculty, Istanbul University-Cerrahpasa, Avcilar, Istanbul, Turkey
| | - Meltem Ulutas Esatgil
- 4 Department of Parasitology, Veterinary Faculty, Istanbul University-Cerrahpasa, Avcilar, Istanbul, Turkey
| | - Christine Klaus
- 5 Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Bacterial Infections and Zoonoses, Jena, Germany
| | - Juergen A Richt
- 6 Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas
| | - Nuri Turan
- 1 Department of Virology, Veterinary Faculty, Istanbul University-Cerrahpasa, Avcilar, Istanbul, Turkey
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14
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Jahfari S, de Vries A, Rijks JM, Van Gucht S, Vennema H, Sprong H, Rockx B. Tick-Borne Encephalitis Virus in Ticks and Roe Deer, the Netherlands. Emerg Infect Dis 2018; 23:1028-1030. [PMID: 28518024 PMCID: PMC5443429 DOI: 10.3201/eid2306.161247] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
We report the presence of tick-borne encephalitis virus (TBEV) in the Netherlands. Serologic screening of roe deer found TBEV-neutralizing antibodies with a seroprevalence of 2%, and TBEV RNA was detected in 2 ticks from the same location. Enhanced surveillance and awareness among medical professionals has led to the identification of autochthonous cases.
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15
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Böhm B, Schade B, Bauer B, Hoffmann B, Hoffmann D, Ziegler U, Beer M, Klaus C, Weissenböck H, Böttcher J. Tick-borne encephalitis in a naturally infected sheep. BMC Vet Res 2017; 13:267. [PMID: 28830430 PMCID: PMC5567888 DOI: 10.1186/s12917-017-1192-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 08/11/2017] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Tick-borne encephalitis (TBE) is the most important viral tick borne zoonosis in Europe. In Germany, about 250 human cases are registered annually, with the highest incidence reported in the last years coming from the federal states Bavaria and Baden-Wuerttemberg. In veterinary medicine, only sporadic cases in wild and domestic animals have been reported; however, a high number of wild and domestic animals have tested positive for the tick-borne encephalitis virus (TBEV) antibody. CASE PRESENTATION In May 2015, a five-month-old lamb from a farm with 15 Merino Land sheep and offspring in Nersingen/Bavaria, a TBEV risk area, showed impaired general health with pyrexia and acute neurological signs. The sheep suffered from ataxia, torticollis, tremor, nystagmus, salivation and finally somnolence with inappetence and recumbency. After euthanasia, pathological, histopathological, immunohistochemical, bacteriological, parasitological and virological analyses were performed. Additionally, blood samples from the remaining, healthy sheep in the herd were taken for detection of TBEV antibody titres. At necropsy and accompanying parasitology, the sheep showed a moderate to severe infection with Trichostrongylids, Moniezia and Eimeria species. Histopathology revealed mild to moderate necrotising, lymphohistiocytic and granulocytic meningoencephalitis with gliosis and neuronophagia. Immunohistochemistry for TBEV was negative. RNA of a TBEV strain, closely related to the Kumlinge A52 strain, was detected in the brain by quantitative reverse transcriptase polymerase chain reaction (RT-qPCR) and subsequent PCR product sequencing. A phylogenetic analysis revealed a close relationship to the TBEV of central Europe. TBEV was cultured from brain tissue. Serologically, one of blood samples from the other sheep in the herd was positive for TBEV in an enzyme-linked immunosorbent assay (ELISA) and in a serum neutralisation test (SNT), and one was borderline in an ELISA. CONCLUSION To the authors' knowledge this is the first report of a natural TBEV infection in a sheep in Europe with clinical manifestation, which describes the clinical presentation and the histopathology of TBEV infection.
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Affiliation(s)
- Brigitte Böhm
- Bavarian Animal Health Service, Senator-Gerauer-Straße 23, 85586, Poing, Germany.
| | - Benjamin Schade
- Bavarian Animal Health Service, Senator-Gerauer-Straße 23, 85586, Poing, Germany
| | - Benjamin Bauer
- Bavarian Animal Health Service, Senator-Gerauer-Straße 23, 85586, Poing, Germany
| | - Bernd Hoffmann
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institute, Südufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Donata Hoffmann
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institute, Südufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Ute Ziegler
- Institute of Novel and Emerging Infectious Diseases, Friedrich-Loeffler-Institute, Südufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Martin Beer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institute, Südufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Christine Klaus
- Institute of bacterial Zoonoses and Infections, Friedrich-Loeffler-Institute, Naumburger Straße 96 a, 07743, Jena, Germany
| | - Herbert Weissenböck
- Institute of Pathology and Forensic Veterinary Medicine, University of Veterinary Medicine, Veterinärplatz 1, 1210, Vienna, Austria
| | - Jens Böttcher
- Bavarian Animal Health Service, Senator-Gerauer-Straße 23, 85586, Poing, Germany
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16
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Seroprevalence of tick-borne-encephalitis virus in wild game in Mecklenburg-Western Pomerania (north-eastern Germany). Ticks Tick Borne Dis 2016; 7:1151-1154. [PMID: 27527383 DOI: 10.1016/j.ttbdis.2016.08.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 08/05/2016] [Accepted: 08/10/2016] [Indexed: 12/30/2022]
Abstract
Mecklenburg-Western Pomerania, a federal state in the north east of Germany, has never been a risk area for TBEV infection, but a few autochthonous cases, along with TBEV-RNA detection in ticks, have shown a low level of activity in natural foci of the virus in the past. As wild game and domestic animals have been shown to be useful sentinels for TBEV we examined sera from wild game shot in Mecklenburg-Western Pomerania for the prevalence of TBEV antibodies. A total of 359 sera from wild game were investigated. All animals were shot in Mecklenburg-Western Pomerania in 2012. Thirteen of 359 sera tested positive or borderline for anti-TBEV-IgG with ELISA and four samples tested positive using NT. The four TBEV-positive sera confirmed by NT constitute the first detection of TBEV-antibodies in sera of wild game in Mecklenburg-Western Pomerania since 1986-1989. This underlines that the serological examination of wild game can be a useful tool in defining areas of possible TBEV infection, especially in areas of low TBEV-endemicity.
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17
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Klaus C, Gethmann J, Hoffmann B, Ziegler U, Heller M, Beer M. Tick infestation in birds and prevalence of pathogens in ticks collected from different places in Germany. Parasitol Res 2016; 115:2729-40. [PMID: 27048511 PMCID: PMC4914531 DOI: 10.1007/s00436-016-5022-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 03/17/2016] [Indexed: 01/12/2023]
Abstract
The importance of ticks and tick-borne pathogens for human and animal health has been increasing over the past decades. For their transportation and dissemination, birds may play a more important role than wingless hosts. In this study, tick infestation of birds in Germany was examined. Eight hundred ninety-two captured birds were infested with ticks and belonged to 48 different species, of which blackbirds (Turdus merula) and song thrushes (Turdus philomelos) were most strongly infested. Ground feeders were more strongly infested than non-ground feeders, sedentary birds more strongly than migratory birds, and short-distance migratory birds more strongly than long-distance migratory birds. Mean tick infestation per bird ranged between 2 (long-distance migratory bird) and 4.7 (sedentary bird), in some single cases up to 55 ticks per bird were found. With the exception of three nymphs of Haemaphysalis spp., all ticks belonged to Ixodes spp., the most frequently detected tick species was Ixodes ricinus. Birds were mostly infested by nymphs (65.1 %), followed by larvae (32.96 %). Additionally, ticks collected from birds were examined for several pathogens: Tick-borne encephalitis virus (TBEV) and Sindbisvirus with real-time RT-PCR, Flaviviruses, Simbuviruses and Lyssaviruses with broad-range standard RT-PCR-assays, and Borrelia spp. with a Pan-Borrelia real-time PCR. Interestingly, no viral pathogens could be detected, but Borrelia spp. positive ticks were collected from 76 birds. Borrelia (B.) garinii, B. valaisiaina, B. burgdorferi s.s. and B. afzelii were determined. The screening of ticks and birds for viral pathogens with broad range PCR-assays was tested and the use as an “early warning system” is discussed.
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Affiliation(s)
- Christine Klaus
- Friedrich-Loeffler-Institute, Institute of Bacterial Infections and Zoonoses, Naumburger Str. 96a, D-07743, Jena, Germany.
| | - Jörn Gethmann
- Friedrich-Loeffler-Institute, Institute of Epidemiology, Greifswald, Insel Riems, Germany
| | - Bernd Hoffmann
- Friedrich-Loeffler-Institute, Institute of Diagnostic Virology, Greifswald, Insel Riems, Germany
| | - Ute Ziegler
- Friedrich-Loeffler-Institute, Institute of Novel and Emerging Diseases, Greifswald, Insel Riems, Germany
| | - Martin Heller
- Friedrich-Loeffler-Institute, Institute of Molecular Pathogenesis, Jena, Germany
| | - Martin Beer
- Friedrich-Loeffler-Institute, Institute of Diagnostic Virology, Greifswald, Insel Riems, Germany
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18
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Imhoff M, Hagedorn P, Schulze Y, Hellenbrand W, Pfeffer M, Niedrig M. Review: Sentinels of tick-borne encephalitis risk. Ticks Tick Borne Dis 2015; 6:592-600. [PMID: 26005107 DOI: 10.1016/j.ttbdis.2015.05.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Revised: 04/15/2015] [Accepted: 05/01/2015] [Indexed: 12/28/2022]
Abstract
Tick-borne encephalitis (TBE) is a viral zoonotic disease endemic in many regions of Eurasia. The definition of TBE risk areas is complicated by the focal nature of the TBE virus transmission. Furthermore, vaccination may reduce case numbers and thus mask infection risk to unvaccinated persons. Therefore, additional risk indicators are sought to complement the current risk assessment solely based on human incidence. We reviewed studies published over the past ten years investigating potential new sentinels of TBE risk to understand the advantages and disadvantages of the various sentinel animal surveys and surrogate indicator methods. Virus prevalence in questing ticks is an unsuitable indicator of TBE infection risk as viral RNA is rarely detected even in large sample sizes collected at known TBE endemic areas. Seroprevalence in domestic animals, on the other hand, showed good spatial correlation with TBE incidence in humans and might also uncover presently unknown TBEV foci.
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Affiliation(s)
- Maren Imhoff
- Centre for Biological Threats and Special Pathogens: Highly Pathogenic Viruses (ZBS 1), Robert Koch Institute, Nordufer 20, 13353 Berlin, Germany.
| | - Peter Hagedorn
- Centre for Biological Threats and Special Pathogens: Highly Pathogenic Viruses (ZBS 1), Robert Koch Institute, Nordufer 20, 13353 Berlin, Germany.
| | - Yesica Schulze
- Centre for Biological Threats and Special Pathogens: Highly Pathogenic Viruses (ZBS 1), Robert Koch Institute, Nordufer 20, 13353 Berlin, Germany.
| | - Wiebke Hellenbrand
- Centre for Biological Threats and Special Pathogens: Highly Pathogenic Viruses (ZBS 1), Robert Koch Institute, Nordufer 20, 13353 Berlin, Germany.
| | - Martin Pfeffer
- Institute of Animal Hygiene & Veterinary Public Health, Centre of Veterinary Public Health, University of Leipzig, An den Tierkliniken 1, 04103 Leipzig, Germany.
| | - Matthias Niedrig
- Centre for Biological Threats and Special Pathogens: Highly Pathogenic Viruses (ZBS 1), Robert Koch Institute, Nordufer 20, 13353 Berlin, Germany.
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19
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Drelich A, Andreassen Å, Vainio K, Kruszyński P, Wąsik TJ. Prevalence of tick-borne encephalitis virus in a highly urbanized and low risk area in Southern Poland. Ticks Tick Borne Dis 2014; 5:663-7. [PMID: 25108791 DOI: 10.1016/j.ttbdis.2014.04.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Revised: 03/17/2014] [Accepted: 04/27/2014] [Indexed: 12/30/2022]
Abstract
The knowledge of the exact distribution of tick-borne encephalitis virus (TBEV) endemic foci is crucial to plan and implement the optimal prevention of tick-borne encephalitis (TBE), including a vaccination program. In Poland, however, there is still no data on the local distribution of TBEV in many areas of the country. Silesian agglomeration area (Southern Poland) is a highly urbanized and industrialized region of the country, where TBE cases are only sporadically recorded. In this study, a total of 4350 adult Ixodes ricinus were collected between September 2010 and June 2012 at twelve locations. The screening using real-time PCR was carried out on 854 tick pools of five specimens, and the positive pools were verified by pyrosequencing. TBEV was identified in 13 pools (1.52%) at 4 sites, of which 9 pools were verified by pyrosequencing. An overall pool prevalence was estimated at 0.31% ranging from 0.19% to 1.11% for positive locations [95% CI 0.16-0.52], which is comparable with regions with high number of TBE cases reported annually.
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Affiliation(s)
- Aleksandra Drelich
- Department and Institute of Microbiology and Virology, The School of Pharmacy and Division of Laboratory Medicine, Medical University of Silesia, Katowice, Poland
| | - Åshild Andreassen
- Division of Infectious Disease Control, Department of Virology, Norwegian Institute of Public Health, Oslo, Norway
| | - Kirsti Vainio
- Division of Infectious Disease Control, Department of Virology, Norwegian Institute of Public Health, Oslo, Norway
| | - Piotr Kruszyński
- Department and Institute of Microbiology and Virology, The School of Pharmacy and Division of Laboratory Medicine, Medical University of Silesia, Katowice, Poland
| | - Tomasz J Wąsik
- Department and Institute of Microbiology and Virology, The School of Pharmacy and Division of Laboratory Medicine, Medical University of Silesia, Katowice, Poland.
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20
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Frimmel S, Krienke A, Riebold D, Loebermann M, Littmann M, Fiedler K, Klaus C, Süss J, Reisinger EC. Tick-borne encephalitis virus habitats in North East Germany: reemergence of TBEV in ticks after 15 years of inactivity. BIOMED RESEARCH INTERNATIONAL 2014; 2014:308371. [PMID: 25110671 PMCID: PMC4109299 DOI: 10.1155/2014/308371] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 06/06/2014] [Indexed: 12/30/2022]
Abstract
The incidence of tick-borne encephalitis has risen in Europe since 1990 and the tick-borne encephalitis virus (TBEV) has been documented to be spreading into regions where it was not previously endemic. In Mecklenburg-West Pomerania, a federal state in Northern Germany, TBEV was not detectable in over 16,000 collected ticks between 1992 and 2004. Until 2004, the last human case of TBE in the region was reported in 1985. Following the occurrence of three autochthonous human cases of TBE after 2004, however, we collected ticks from the areas in which the infections were contracted. To increase the chance of detecting TBEV-RNA, some of the ticks were fed on mice. Using nested RT-PCR, we were able to confirm the presence of TBEV in ticks for the first time after 15 years. A phylogenetic analysis revealed a close relationship between the sequences we obtained and a TBEV sequence from Mecklenburg-East Pomerania published in 1992 and pointed to the reemergence of a natural focus of TBEV after years of low activity. Our results imply that natural foci of TBEV may either persist at low levels of activity for years or reemerge through the agency of migrating birds.
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Affiliation(s)
- Silvius Frimmel
- Department of Tropical Medicine, Infectious Diseases and Nephrology, University of Rostock Medical School, Ernst-Heydemann-Straße 6, 18057 Rostock, Germany
| | - Anja Krienke
- Department of Tropical Medicine, Infectious Diseases and Nephrology, University of Rostock Medical School, Ernst-Heydemann-Straße 6, 18057 Rostock, Germany
| | - Diana Riebold
- Department of Tropical Medicine, Infectious Diseases and Nephrology, University of Rostock Medical School, Ernst-Heydemann-Straße 6, 18057 Rostock, Germany
| | - Micha Loebermann
- Department of Tropical Medicine, Infectious Diseases and Nephrology, University of Rostock Medical School, Ernst-Heydemann-Straße 6, 18057 Rostock, Germany
| | - Martina Littmann
- Health Department of the State of Mecklenburg-West Pomerania, 18055 Rostock, Germany
| | - Karin Fiedler
- Health Department of the State of Mecklenburg-West Pomerania, 18055 Rostock, Germany
| | - Christine Klaus
- Friedrich-Loeffler-Institute Jena, National Reference Laboratory for Tick-Borne Diseases, 07743 Jena, Germany
| | - Jochen Süss
- Tick Information Center, 07646 Lippersdorf, Germany
| | - Emil Christian Reisinger
- Department of Tropical Medicine, Infectious Diseases and Nephrology, University of Rostock Medical School, Ernst-Heydemann-Straße 6, 18057 Rostock, Germany
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Klaus C, Ziegler U, Kalthoff D, Hoffmann B, Beer M. Tick-borne encephalitis virus (TBEV) - findings on cross reactivity and longevity of TBEV antibodies in animal sera. BMC Vet Res 2014; 10:78. [PMID: 24690234 PMCID: PMC3978054 DOI: 10.1186/1746-6148-10-78] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Accepted: 03/26/2014] [Indexed: 12/20/2022] Open
Abstract
Background By using animal sera as sentinels, natural TBEV foci could be identified and further analyses including investigations of ticks could be initiated. However, antibody response against TBEV-related flaviviruses might adversely affect the readout of such a monitoring. Therefore, the cross-reactivity of the applied TBEV serology test systems – enzyme linked immunosorbent assay (ELISA) and virus neutralization test (VNT) – as well as the longevity of TBEV antibody titres in sheep and goats were investigated in this study. Results Cross-reactivity of the TBEV antibody test systems with defined antibody-positive samples against selected members of the Flaviviridae family (e.g. Louping ill virus, West Nile virus) was observed for Louping-ill-positive sera only. In contrast, the commercial West Nile virus (WNV) competitive ELISA showed a high level of cross-reactivity with TBEV-specific positive sera. To assess the longevity of TBEV antibody titres, sera from two sheep and two goats, which had been immunized four times with a commercially available TBEV vaccine, were tested routinely over 28 months. In three of the four animals, TBEV-specific antibody titres could be detected over the whole test period. In addition, sera from the years 2010 and 2011 were collected in flocks in different villages of Baden-Württemberg and Thuringia to allow re-examination two to four years after the initial analysis. Interestingly, in most cases the results of the former investigations were confirmed, which may be caused by steadily existing natural TBEV foci. Conclusion Cross-reactivity must be taken into consideration, particularly for TBEV serology in regions with a prevalence of Louping ill virus and for serological testing of WNV by cross-reactive ELISAs. Furthermore, over-interpretation of single TBEV-positive serological results should be avoided, especially in areas without a TBEV history.
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Affiliation(s)
- Christine Klaus
- Institute of Bacterial Infections and Zoonoses, Friedrich-Loeffler-Institut, Naumburger Str, 96a, D-07743 Jena, Germany.
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22
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Lindblom P, Wilhelmsson P, Fryland L, Sjöwall J, Haglund M, Matussek A, Ernerudh J, Vene S, Nyman D, Andreassen A, Forsberg P, Lindgren PE. Tick-borne encephalitis virus in ticks detached from humans and follow-up of serological and clinical response. Ticks Tick Borne Dis 2013; 5:21-8. [PMID: 24275477 DOI: 10.1016/j.ttbdis.2013.07.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 07/14/2013] [Indexed: 12/20/2022]
Abstract
The risk of tick-borne encephalitis virus (TBEV) infection after a tick bite remains largely unknown. To address this, we investigated the presence of TBEV in ticks detached from humans in an attempt to relate viral copy number, TBEV subtype, and tick feeding time with the serological and clinical response of the tick-bitten participants. Ticks, blood samples, and questionnaires were collected from tick-bitten humans at 34 primary health care centers in Sweden and in the Åland Islands (Finland). A total of 2167 ticks was received from 1886 persons in 2008-2009. Using a multiplex quantitative real-time PCR, 5 TBEV-infected ticks were found (overall prevalence 0.23%, copy range <4×10(2)-7.7×10(6)per tick). One unvaccinated person bitten by a tick containing 7.7×10(6) TBEV copies experienced symptoms. Another unvaccinated person bitten by a tick containing 1.8×10(3) TBEV copies developed neither symptoms nor TBEV antibodies. The remaining 3 persons were protected by vaccination. In contrast, despite lack of TBEV in the detached ticks, 2 persons developed antibodies against TBEV, one of whom reported symptoms. Overall, a low risk of TBEV infection was observed, and too few persons got bitten by TBEV-infected ticks to draw certain conclusions regarding the clinical outcome in relation to the duration of the blood meal and virus copy number. However, this study indicates that an antibody response may develop without clinical symptoms, that a bite by an infected tick not always leads to an antibody response or clinical symptoms, and a possible correlation between virus load and tick feeding time.
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Affiliation(s)
- Pontus Lindblom
- Division of Medical Microbiology, Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.
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23
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Weidmann M, Frey S, Freire CCM, Essbauer S, Růžek D, Klempa B, Zubrikova D, Vögerl M, Pfeffer M, Hufert FT, Zanotto PM, Dobler G. Molecular phylogeography of tick-borne encephalitis virus in central Europe. J Gen Virol 2013; 94:2129-2139. [PMID: 23784447 DOI: 10.1099/vir.0.054478-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
In order to obtain a better understanding of tick-borne encephalitis virus (TBEV) strain movements in central Europe the E gene sequences of 102 TBEV strains collected from 1953 to 2011 at 38 sites in the Czech Republic, Slovakia, Austria and Germany were determined. Bayesian analysis suggests a 350-year history of evolution and spread in central Europe of two main lineages, A and B. In contrast to the east to west spread at the Eurasian continent level, local central European spreading patterns suggest historic west to east spread followed by more recent east to west spread. The phylogenetic and network analyses indicate TBEV ingressions from the Czech Republic and Slovakia into Germany via landscape features (Danube river system), biogenic factors (birds, red deer) and anthropogenic factors. The identification of endemic foci showing local genetic diversity is of paramount importance to the field as these will be a prerequisite for in-depth analysis of focal TBEV maintenance and long-distance TBEV spread.
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Affiliation(s)
- Manfred Weidmann
- Department of Virology, University Medical Center, 37075 Göttingen, Germany
| | - Stefan Frey
- Bundeswehr Institute of Microbiology, 80937 Munich, Germany
| | - Caio C M Freire
- Department of Microbiology, Biomedical Sciences Institute - ICB II University of São Paulo, 05508-000 São Paulo, Brazil
| | | | - Daniel Růžek
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Branisovska 31, CZ-37005 Ceske Budejovice, Czech Republic.,Department of Virology, Veterinary Research Institute, Hudcova 70, CZ-62100 Brno, Czech Republic
| | - Boris Klempa
- Institute of Virology Charité University Hospital, Berlin, Germany.,Institute of Virology, Slovak Academy of Science, Dubravska cesta 9, 84505 Bratislava, Slovakia
| | - Dana Zubrikova
- Institute of Parasitology, Slovak Academy of Science, Kosice, Slovakia
| | - Maria Vögerl
- Comparative Tropical Medicine and Parasitology, Faculty of Veterinary Medicine, Ludwig-Maximilians-University, Munich, Germany
| | - Martin Pfeffer
- Institute of Animal Hygiene and Veterinary Public Health, University of Leipzig, Leipzig, Germany
| | - Frank T Hufert
- Department of Virology, University Medical Center, 37075 Göttingen, Germany
| | - Paolo M Zanotto
- Department of Microbiology, Biomedical Sciences Institute - ICB II University of São Paulo, 05508-000 São Paulo, Brazil
| | - Gerhard Dobler
- Bundeswehr Institute of Microbiology, 80937 Munich, Germany
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24
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Tick-borne encephalitis virus (TBEV) infection in horses: Clinical and laboratory findings and epidemiological investigations. Vet Microbiol 2013; 163:368-72. [DOI: 10.1016/j.vetmic.2012.12.041] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Revised: 12/21/2012] [Accepted: 12/22/2012] [Indexed: 12/30/2022]
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25
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Bingsohn L, Beckert A, Zehner R, Kuch U, Oehme R, Kraiczy P, Amendt J. Prevalences of tick-borne encephalitis virus and Borrelia burgdorferi sensu lato in Ixodes ricinus populations of the Rhine-Main region, Germany. Ticks Tick Borne Dis 2013; 4:207-13. [PMID: 23415373 DOI: 10.1016/j.ttbdis.2012.11.012] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Revised: 11/14/2012] [Accepted: 11/20/2012] [Indexed: 12/30/2022]
Abstract
Tick-borne encephalitis (TBE) and Lyme borreliosis are the most common tick-borne zooanthroponoses in Germany. The federal risk map for TBE in this country is based on recorded cases of human infection, whereas information on the vector-based prevalence of either pathogen is fragmentary. In this study, a total of 12,497 host-seeking nymphal and adult Ixodes ricinus ticks (Acari: Ixodidae) were collected from March to October 2009 and April to June 2010, in 5 TBE non-risk and 4 TBE risk areas of the Rhine-Main region (Hesse) via flagging. A total of 3615 ticks was examined for infection with Borrelia burgdorferi sensu lato and 9115 ticks were analyzed for TBE virus (TBEV). Pathogens were detected by real-time polymerase chain reaction. Among 3615 questing ticks, 344 (9.5%) were found infected with B. burgdorferi sensu lato. Five Borrelia genospecies were identified by sequencing the OspA gene: B. afzelii (81.3%), B. garinii (14.0%), B. valaisiana (2.7%), B. spielmanii (1.3%), and B. bavariensis (0.7%). TBE infection of ticks differed between areas classified as TBE risk and TBE non-risk areas. While the prevalence of TBEV was between 0 and 0.2% (3 of 3947 ticks) in the TBE risk areas, no TBEV-infected tick was detected from TBE non-risk areas. The results show that B. burgdorferi sensu lato occurred in all 9 examined locations, indicating that Lyme borreliosis is prevalent in the Rhine-Main region, whereas TBEV was detected only in previously classified risk areas.
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Affiliation(s)
- Linda Bingsohn
- Division of Medical Entomology, Institute of Forensic Medicine, Goethe University Hospital, 60596 Frankfurt am Main, Germany
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26
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Andreassen A, Jore S, Cuber P, Dudman S, Tengs T, Isaksen K, Hygen HO, Viljugrein H, Ånestad G, Ottesen P, Vainio K. Prevalence of tick borne encephalitis virus in tick nymphs in relation to climatic factors on the southern coast of Norway. Parasit Vectors 2012; 5:177. [PMID: 22913287 PMCID: PMC3497858 DOI: 10.1186/1756-3305-5-177] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Accepted: 07/30/2012] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Tick-borne encephalitis (TBE) is among the most important vector borne diseases of humans in Europe and is currently identified as a major health problem in many countries. TBE endemic zones have expanded over the past two decades, as well as the number of reported cases within endemic areas. Multiple factors are ascribed for the increased incidence of TBE, including climatic change. The number of TBE cases has also increased in Norway over the past decade, and the human cases cluster along the southern coast of Norway. In Norway the distribution and prevalence of TBE virus (TBEV) in tick populations is largely unknown. The objectives of this study were to estimate the TBEV prevalence in Ixodes ricinus from seven locations and to assess the relationship between the TBEV prevalence and site-specific climatic variables. METHODS A total of 5630 questing nymphs were collected and analyzed in pools of ten. All pools were screened with an in-house real-time RT-PCR, and the positive pools were pyrosequenced. Two methods, minimum infection rate (MIR) and a frequentist method (EPP) for pooled prevalence estimations were calculated and compared. Climatic data were descriptively compared to the corresponding EPP of each location in order to explain variations in TBEV prevalence. RESULTS The seven foci of TBEV had an estimated overall prevalence (EPP) in pools of nymphs combined, of 0.53% with 95% CI (0.35-0.75), with point prevalence ranging between 0.11%-1.22%. The sites with the highest point prevalences were within the municipalities which had the highest numbers of registered TBE cases. The results indicate that the location with highest point prevalence had the highest relative mean humidity and lowest mean saturation deficit and vice versa for the lowest EPP. CONCLUSION Our study confirms the existence of TBEV endemic foci in Norway. These results are of importance to increase the awareness of TBEV infections in Norway and could be used for public information and recommendations of TBE vaccination. EPP is the method of choice for pooled prevalence calculations, since it provides estimated prevalences with confidence intervals. Our findings emphasise the possible importance of microclimatic conditions regarding the TBEV prevalence in ticks.
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Affiliation(s)
- Ashild Andreassen
- Division of Infectious Disease Control, Department of Virology, Norwegian Institute of Public Health, P. O. Box 4404, Nydalen, 0403, Oslo, Norway
| | - Solveig Jore
- Norwegian Veterinary Institute, Ullevålsveien 68, P.O.Box 750, centrum, 0106, Oslo, Norway
| | - Piotr Cuber
- School of Pharmacy, Department of Parasitology, Medical University of Silesia in Katowice, 41-218, Sosnowiec, Ul. Jedności 8, Poland
| | - Susanne Dudman
- Division of Infectious Disease Control, Department of Virology, Norwegian Institute of Public Health, P. O. Box 4404, Nydalen, 0403, Oslo, Norway
| | - Torstein Tengs
- Norwegian Veterinary Institute, Ullevålsveien 68, P.O.Box 750, centrum, 0106, Oslo, Norway
| | - Ketil Isaksen
- The Norwegian Meteorological Institute, Oslo, Norway
| | | | - Hildegunn Viljugrein
- Norwegian Veterinary Institute, Ullevålsveien 68, P.O.Box 750, centrum, 0106, Oslo, Norway
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biology, University of Oslo, Oslo, Norway
| | - Gabriel Ånestad
- Division of Infectious Disease Control, Department of Virology, Norwegian Institute of Public Health, P. O. Box 4404, Nydalen, 0403, Oslo, Norway
| | - Preben Ottesen
- Department of Pest Control, Norwegian Institute of Public Health, P. O. Box 4404, Nydalen, 0403, Oslo, Norway
| | - Kirsti Vainio
- Division of Infectious Disease Control, Department of Virology, Norwegian Institute of Public Health, P. O. Box 4404, Nydalen, 0403, Oslo, Norway
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Stefanoff P, Pfeffer M, Hellenbrand W, Rogalska J, Rühe F, Makówka A, Michalik J, Wodecka B, Rymaszewska A, Kiewra D, Baumann-Popczyk A, Dobler G. Virus detection in questing ticks is not a sensitive indicator for risk assessment of tick-borne encephalitis in humans. Zoonoses Public Health 2012; 60:215-26. [PMID: 22765504 DOI: 10.1111/j.1863-2378.2012.01517.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Tick-borne encephalitis virus (TBEV) is the most important tick-transmitted arbovirus causing human disease in Europe, but information on its endemic occurrence varies between countries because of differences in surveillance systems. Objective data are necessary to ascertain the disease risk for vaccination recommendations and other public health interventions. In two independent, separately planned projects, we used real-time RT-PCR to detect TBE virus in questing ticks. In Poland, 32 sampling sites were selected in 10 administrative districts located in regions where sporadic TBE cases were reported. In Germany, 18 sampling sites were selected in two districts located in a region with high TBE incidence. Altogether, >16,000 ticks were tested by real-time RT-PCR, with no sample testing positive for TBEV. A systematic search for published studies on TBEV prevalence in ticks in Poland and Germany also suggested that testing large numbers of collected ticks could not consistently assure virus detection in known endemic foci. Although assignment of results to administrative regions is essential for TBE risk mapping, this was possible in only 10 (investigating 22,417 ticks) of 15 published studies (>50,000 ticks) identified. We conclude that the collection and screening of ticks by real-time RT-PCR cannot be recommended for assessment of human TBE risk. Alternative methods of environmental TBEV monitoring should be considered, such as serological monitoring of rodents or other wildlife.
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Affiliation(s)
- P Stefanoff
- Department of Epidemiology, National Institute of Public Health-National Institute of Hygiene, Warsaw, Poland.
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28
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Kiffner C, Vor T, Hagedorn P, Niedrig M, Rühe F. Determinants of tick-borne encephalitis virus antibody presence in roe deer (Capreolus capreolus) sera. MEDICAL AND VETERINARY ENTOMOLOGY 2012; 26:18-25. [PMID: 21592155 DOI: 10.1111/j.1365-2915.2011.00961.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In order to identify variables associated with the presence of the tick-borne encephalitis (TBE) virus, we conducted a serological survey of roe deer [Capreolus capreolus (Artiodactyla: Cervidae, Linnaeus 1758)] in three forest districts of southern Hesse, Germany. Overall, 24 out of 105 (22.9%) of the sera were positive (≥1 : 10 plaque reduction neutralization test). Using a logistic regression approach, we found that unexplained spatial variation, indexed roe deer density (positive correlation), hind foot length of the tested roe deer (positive correlation) and infestation with female Ixodes spp. ticks (negative correlation) predicted the probability of TBE virus antibody presence in individual roe deer sera. Spring temperature increase and host sex were rejected as explanatory variables. We found considerable differences in TBE virus antibody seroprevalence (50.0% vs. 17.6%) between two forest districts located in the same county; this finding questions the current county-resolution of public health recordings. Given the high seroprevalence of roe deer and the considerable explanatory power of our model, our approach appears suitable to delineate science-based risk maps at a smaller spatial scale and to abandon the current human incidence per county criterion. Importantly, using roe deer as sentinels would eliminate the inherent bias of risk maps based on human incidence (varying levels of immunization and exposure of humans).
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Affiliation(s)
- C Kiffner
- Department of Forest Zoology and Forest Conservation incl. Wildlife Biology and Game Management, Büsgen-Institute, Georg-August-University Göttingen, Busgenweg 3, Göttingen, Germany.
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29
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Klaus C, Beer M, Saier R, Schau U, Moog U, Hoffmann B, Diller R, Süss J. Goats and sheep as sentinels for tick-borne encephalitis (TBE) virus--epidemiological studies in areas endemic and non-endemic for TBE virus in Germany. Ticks Tick Borne Dis 2011; 3:27-37. [PMID: 22309856 DOI: 10.1016/j.ttbdis.2011.09.011] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Revised: 08/22/2011] [Accepted: 09/19/2011] [Indexed: 12/30/2022]
Abstract
The aim of the study was to examine grazing goats and sheep as specific sentinels for characterization of the tick-borne encephalitis virus (TBEV)-related risk in an area by means of serosurveillance tests in the German federal states Baden-Wuerttemberg, Bavaria, Thuringia, North Rhine-Westphalia, Lower Saxony, Schleswig-Holstein, and Mecklenburg-West Pomerania. A total of 3590 sheep sera and 3793 goat sera was collected in 2003 and 2006-2009 and were examined by ELISA screening and confirmed by serum neutralization test. Considerable differences in seroprevalence were seen between single flocks in districts in Baden-Wuerttemberg, Bavaria, and Thuringia with values between 0 and 43% which confirmed the patchy pattern of TBEV foci that can range in size from very small to large. The here described serological screening may be a helpful tool for an early warning system of a potential TBEV risk. Testing of 1700 ticks by real-time RT-PCR in two districts in Baden-Wuerttemberg revealed only one positive tick, thus illustrating the problems of expensive and time-consuming tick collection.
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Affiliation(s)
- Christine Klaus
- Friedrich-Loeffler-Institut, Jena, Greifswald-Insel Riems, Germany.
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Elväng A, Melik W, Bertrand Y, Lönn M, Johansson M. Sequencing of a tick-borne encephalitis virus from Ixodes ricinus reveals a thermosensitive RNA switch significant for virus propagation in ectothermic arthropods. Vector Borne Zoonotic Dis 2011; 11:649-58. [PMID: 21254926 DOI: 10.1089/vbz.2010.0105] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Tick-borne encephalitis virus (TBEV) is a flavivirus with major impact on global health. The geographical TBEV distribution is expanding, thus making it pivotal to further characterize the natural virus populations. In this study, we completed the earlier partial sequencing of a TBEV pulled out of a pool of RNA extracted from 115 ticks collected on Torö in the Stockholm archipelago. The total RNA was sufficient for all sequencing of a TBEV genome (Torö-2003), without conventional enrichment procedures such as cell culturing or suckling mice amplification. To our knowledge, this is the first time that the genome of TBEV has been sequenced directly from an arthropod reservoir. The Torö-2003 sequence has been characterized and compared with other TBE viruses. In silico analyses of secondary RNA structures formed by the two untranslated regions revealed a temperature-sensitive structural shift between a closed replicative form and an open AUG accessible form, analogous to a recently described bacterial thermoswitch. Additionally, novel phylogenetic conserved structures were identified in the variable part of the 3'-untranslated region, and their sequence and structure similarity when compared with earlier identified structures suggests an enhancing function on virus replication and translation. We propose that the thermo-switch mechanism may explain the low TBEV prevalence often observed in environmentally sampled ticks. Finally, we were able to detect variations that help in the understanding of virus adaptations to varied environmental temperatures and mammalian hosts through a comparative approach that compares RNA folding dynamics between strains with different mammalian cell passage histories.
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Affiliation(s)
- Annelie Elväng
- School of Life Sciences, Södertörn University, Huddinge, Sweden
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Klaus C, Hoffmann B, Beer M, Müller W, Stark B, Bader W, Stiasny K, Heinz FX, Süss J. Seroprevalence of tick-borne encephalitis (TBE) in naturally exposed monkeys (Macaca sylvanus) and sheep and prevalence of TBE virus in ticks in a TBE endemic area in Germany. Ticks Tick Borne Dis 2010; 1:141-4. [DOI: 10.1016/j.ttbdis.2010.06.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Revised: 06/22/2010] [Accepted: 06/22/2010] [Indexed: 11/29/2022]
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32
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Tick-borne encephalitis virus in ticks in Finland, Russian Karelia and Buryatia. J Gen Virol 2010; 91:2706-12. [DOI: 10.1099/vir.0.023663-0] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Prevalence and seasonality of tick-borne pathogens in questing Ixodes ricinus ticks from Luxembourg. Appl Environ Microbiol 2010; 76:2923-31. [PMID: 20228110 DOI: 10.1128/aem.03061-09] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
In Europe, ixodid ticks are important arthropod vectors of human and animal pathogens, but comprehensive studies of the prevalence of all relevant pathogens in Central Europe are scarce. As a result of ecological changes, the incidences of tick-borne infections are expected to increase. In this study, 1,394 nymphal and adult Ixodes ricinus ticks sampled monthly during the active season from 33 ecologically distinct collection sites throughout Luxembourg were screened for all human tick-borne pathogens relevant in Central Europe. Species were identified by sequence analysis of detection PCR amplicons. Mean infection rates of ticks were 11.3% for Borrelia burgdorferi sensu lato, 5.1% for Rickettsia sp., 2.7% for Babesia sp., and 1.9% for Anaplasma phagocytophilum. No tick was found to be infected with Coxiella sp., Francisella tularensis subsp., or Tick-borne encephalitis virus (TBEV). A total of 3.2% of ticks were infected with more than one pathogen species, including mixed Borrelia infections (1.5%). Seasonal variations of tick infection rates were observed for Borrelia, Babesia, and Anaplasma, possibly reflecting a behavioral adaptation strategy of questing ticks. A positive correlation between the grade of urbanization and Borrelia infection rate of ticks was observed, suggesting an established urban zoonotic cycle. We also found Hepatozoon canis (0.1%) and Bartonella henselae (0.3%), which so far have not been found in questing Ixodes ricinus ticks in Central Europe.
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