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Hills SL, Poehling KA, Chen WH, Staples JE. Tick-Borne Encephalitis Vaccine: Recommendations of the Advisory Committee on Immunization Practices, United States, 2023. MMWR Recomm Rep 2023; 72:1-29. [PMID: 37943707 PMCID: PMC10651317 DOI: 10.15585/mmwr.rr7205a1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023] Open
Abstract
Tick-borne encephalitis (TBE) virus is focally endemic in parts of Europe and Asia. The virus is primarily transmitted to humans by the bites of infected Ixodes species ticks but can also be acquired less frequently by alimentary transmission. Other rare modes of transmission include through breastfeeding, blood transfusion, solid organ transplantation, and slaughtering of viremic animals. TBE virus can cause acute neurologic disease, which usually results in hospitalization, often permanent neurologic or cognitive sequelae, and sometimes death. TBE virus infection is a risk for certain travelers and for laboratory workers who work with the virus. In August 2021, the Food and Drug Administration approved Ticovac TBE vaccine for use among persons aged ≥1 year. This report summarizes the epidemiology of and risks for infection with TBE virus, provides information on the immunogenicity and safety of TBE vaccine, and summarizes the recommendations of the Advisory Committee on Immunization Practices (ACIP) for use of TBE vaccine among U.S. travelers and laboratory workers. The risk for TBE for most U.S. travelers to areas where the disease is endemic is very low. The risk for exposure to infected ticks is highest for persons who are in areas where TBE is endemic during the main TBE virus transmission season of April–November and who are planning to engage in recreational activities in woodland habitats or who might be occupationally exposed. All persons who travel to areas where TBE is endemic should be advised to take precautions to avoid tick bites and to avoid the consumption of unpasteurized dairy products because alimentary transmission of TBE virus can occur. TBE vaccine can further reduce infection risk and might be indicated for certain persons who are at higher risk for TBE. The key factors in the risk-benefit assessment for vaccination are likelihood of exposure to ticks based on activities and itinerary (e.g., location, rurality, season, and duration of travel or residence). Other risk-benefit considerations should include 1) the rare occurrence of TBE but its potentially high morbidity and mortality, 2) the higher risk for severe disease among certain persons (e.g., older persons aged ≥60 years), 3) the availability of an effective vaccine, 4) the possibility but low probability of serious adverse events after vaccination, 5) the likelihood of future travel to areas where TBE is endemic, and 6) personal perception and tolerance of risk ACIP recommends TBE vaccine for U.S. persons who are moving or traveling to an area where the disease is endemic and will have extensive exposure to ticks based on their planned outdoor activities and itinerary. Extensive exposure can be considered based on the duration of travel and frequency of exposure and might include shorter-term (e.g., <1 month) travelers with daily or frequent exposure or longer-term travelers with regular (e.g., a few times a month) exposure to environments that might harbor infected ticks. In addition, TBE vaccine may be considered for persons who might engage in outdoor activities in areas where ticks are likely to be found, with a decision to vaccinate made on the basis of an assessment of their planned activities and itinerary, risk factors for a poor medical outcome, and personal perception and tolerance of risk. In the laboratory setting, ACIP recommends TBE vaccine for laboratory workers with a potential for exposure to TBE virus
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Bestehorn-Willmann M, Girl P, Greiner F, Mackenstedt U, Dobler G, Lang D. Increased Vaccination Diversity Leads to Higher and Less-Variable Neutralization of TBE Viruses of the European Subtype. Vaccines (Basel) 2023; 11:1044. [PMID: 37376433 DOI: 10.3390/vaccines11061044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 05/24/2023] [Accepted: 05/27/2023] [Indexed: 06/29/2023] Open
Abstract
Tick-borne encephalitis (TBE) is an infectious disease of the central nervous system. The causative agent is the tick-borne encephalitis virus (TBEV), which is most commonly transmitted by tick bites, but which may also be transmitted through the consumption of raw dairy products or, in rare instances, via infected transfusions, transplants, or the slaughter of infected animals. The only effective preventive option is active immunization. Currently, two vaccines are available in Europe-Encepur® and FSME-IMMUN®. In Central, Eastern, and Northern Europe, isolated TBEV genotypes belong mainly to the European subtype (TBEV-EU). In this study, we investigated the ability of these two vaccines to induce neutralizing antibodies against a panel of diverse natural TBEV-EU isolates from TBE-endemic areas in southern Germany and in regions of neighboring countries. Sera of 33 donors vaccinated with either FSME-IMMUN®, Encepur®, or a mixture of both were tested against 16 TBEV-EU strains. Phylogenetic analysis of the TBEV-EU genomes revealed substantial genetic diversity and ancestry of the identified 13 genotypic clades. Although all sera were able to neutralize the TBEV-EU strains, there were significant differences among the various vaccination groups. The neutralization assays revealed that the vaccination using the two different vaccine brands significantly increased neutralization titers, decreased intra-serum variance, and reduced the inter-virus variation.
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Affiliation(s)
- Malena Bestehorn-Willmann
- Institute for Zoology, Parasitology Unit, University of Hohenheim, 70599 Stuttgart, Germany
- Bundeswehr Institute of Microbiology, 80937 Munich, Germany
| | - Philipp Girl
- Bundeswehr Institute of Microbiology, 80937 Munich, Germany
| | - Franziska Greiner
- Institute for Zoology, Parasitology Unit, University of Hohenheim, 70599 Stuttgart, Germany
| | - Ute Mackenstedt
- Institute for Zoology, Parasitology Unit, University of Hohenheim, 70599 Stuttgart, Germany
| | - Gerhard Dobler
- Institute for Zoology, Parasitology Unit, University of Hohenheim, 70599 Stuttgart, Germany
- Bundeswehr Institute of Microbiology, 80937 Munich, Germany
| | - Daniel Lang
- Bundeswehr Institute of Microbiology, 80937 Munich, Germany
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Brandenburg PJ, Obiegala A, Schmuck HM, Dobler G, Chitimia-Dobler L, Pfeffer M. Seroprevalence of Tick-Borne Encephalitis (TBE) Virus Antibodies in Wild Rodents from Two Natural TBE Foci in Bavaria, Germany. Pathogens 2023; 12:pathogens12020185. [PMID: 36839457 PMCID: PMC9962257 DOI: 10.3390/pathogens12020185] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 01/17/2023] [Accepted: 01/23/2023] [Indexed: 01/26/2023] Open
Abstract
Tick-borne encephalitis (TBE) is Eurasia's most important tick-borne viral disease. Rodents play an important role as natural hosts. Longitudinal studies on the dynamics of the seroprevalence rates in wild rodents in natural foci over the year are rare, and the dynamics of the transmission cycle still need to be understood. To better understand the infection dynamics, rodents were captured in a capture-mark-release-recapture-study in two natural foci in Bavaria, Germany, monthly from March 2019 to October 2022. Overall, 651 blood and thoracic lavage samples from 478 different wild rodents (Clethrionomys glareolus and Apodemus flavicollis) were analyzed for antibodies against tick-borne encephalitis virus (TBEV) by indirect immunofluorescence assay (IIFA) and confirmed using a serum neutralization test (SNT). Furthermore, a generalized linear mixed model (GLMM) analysis was performed to investigate ecological and individual factors for the probability of infection in rodents. Clethrionomys glareolus (19.4%) had a higher seroprevalence than A. flavicollis (10.5%). Within Cl. glareolus, more males (40.4%) than females (15.6%) were affected, and more adults (25.4%) than juveniles (9.8%). The probability of infection of rodents rather depends on factors such as species, sex, and age than on the study site of a natural focus, year, and season. The high incidence rates of rodents, particularly male adult bank voles, highlight their critical role in the transmission cycle of TBEV in a natural focus and demonstrate that serologically positive rodents can be reliably detected in a natural focus regardless of season or year. In addition, these data contribute to a better understanding of the TBEV cycle and thus could improve preventive strategies for human infections.
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Affiliation(s)
- Philipp Johannes Brandenburg
- Institute of Animal Hygiene and Veterinary Public Health, Faculty of Veterinary Medicine, University of Leipzig, An den Tierkliniken 1, 04103 Leipzig, Germany
- Correspondence: ; Tel.: +49-341-97-38150
| | - Anna Obiegala
- Institute of Animal Hygiene and Veterinary Public Health, Faculty of Veterinary Medicine, University of Leipzig, An den Tierkliniken 1, 04103 Leipzig, Germany
| | - Hannah Maureen Schmuck
- Institute of Animal Hygiene and Veterinary Public Health, Faculty of Veterinary Medicine, University of Leipzig, An den Tierkliniken 1, 04103 Leipzig, Germany
| | - Gerhard Dobler
- National Consulting Laboratory for TBE, Bundeswehr Institute of Microbiology, Neuherbergstrasse 11, 80937 Munich, Germany
| | - Lidia Chitimia-Dobler
- National Consulting Laboratory for TBE, Bundeswehr Institute of Microbiology, Neuherbergstrasse 11, 80937 Munich, Germany
| | - Martin Pfeffer
- Institute of Animal Hygiene and Veterinary Public Health, Faculty of Veterinary Medicine, University of Leipzig, An den Tierkliniken 1, 04103 Leipzig, Germany
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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: 9] [Impact Index Per Article: 4.5] [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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Lang D, Chitimia-Dobler L, Bestehorn-Willmann M, Lindau A, Drehmann M, Stroppel G, Hengge H, Mackenstedt U, Kaier K, Dobler G, Borde J. The Emergence and Dynamics of Tick-Borne Encephalitis Virus in a New Endemic Region in Southern Germany. Microorganisms 2022; 10:2125. [PMID: 36363717 PMCID: PMC9693875 DOI: 10.3390/microorganisms10112125] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 10/12/2022] [Accepted: 10/17/2022] [Indexed: 06/11/2024] Open
Abstract
Tick-borne encephalitis (TBE) is the most important viral tick-borne infection in Europe and Asia. It is emerging in new areas. The mechanisms of emergence are fairly unknown or speculative. In the Ravensburg district in southern Germany, TBE emerged, mainly over the last five years. Here, we analyzed the underlying epidemiology in humans. The resulting identified natural foci of the causal TBE virus (TBEV) were genetically characterized. We sampled 13 potential infection sites at these foci and detected TBEV in ticks (Ixodes ricinus) at eight sites. Phylogenetic analysis spurred the introduction of at least four distinct TBEV lineages of the European subtype into the Ravensburg district over the last few years. In two instances, a continuous spread of these virus strains over up to 10 km was observed.
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Affiliation(s)
- Daniel Lang
- National Reference Laboratory for TBEV, Bundeswehr Institute for Microbiology, 80937 Munich, Germany
| | - Lidia Chitimia-Dobler
- National Reference Laboratory for TBEV, Bundeswehr Institute for Microbiology, 80937 Munich, Germany
| | - Malena Bestehorn-Willmann
- National Reference Laboratory for TBEV, Bundeswehr Institute for Microbiology, 80937 Munich, Germany
| | - Alexander Lindau
- Department of Parasitology, University of Hohenheim, 70599 Stuttgart, Germany
| | - Marco Drehmann
- Department of Parasitology, University of Hohenheim, 70599 Stuttgart, Germany
| | - Gabriele Stroppel
- Public Health Office, District Ravensburg, 88212 Ravensburg, Germany
| | - Helga Hengge
- Public Health Office, District Ravensburg, 88212 Ravensburg, Germany
| | - Ute Mackenstedt
- Department of Parasitology, University of Hohenheim, 70599 Stuttgart, Germany
| | - Klaus Kaier
- Institute of Medical Biometry and Statistics (IMBI), University Medical Center Freiburg im Breisgau, 79106 Freiburg im Breisgau, Germany
| | - Gerhard Dobler
- National Reference Laboratory for TBEV, Bundeswehr Institute for Microbiology, 80937 Munich, Germany
- Department of Parasitology, University of Hohenheim, 70599 Stuttgart, Germany
| | - Johannes Borde
- Praxis Prof. Borde & Kollegen, Gesundheitszentrum Oberkirch, 77704 Oberkirch, Germany
- Division of Infectious Diseases, Department of Internal Medicine, University Medical Center Freiburg im Breisgau, 79106 Freiburg im Breisgau, Germany
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European subtype of tick-borne encephalitis virus. Literature review. ACTA BIOMEDICA SCIENTIFICA 2021. [DOI: 10.29413/abs.2021-6.4.9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
This review is devoted to the European subtype of tick-borne encephalitis virus (TBEV). It summarizes and analyzes the information available at the scientific literature on the genetic and biological properties of strains of this virus subtype. A comparative analysis of the complete coding sequences of all currently recognized tick-borne flaviviruses was carried out. It was noted that the differences in TBEV strains included in the European subtype are minimal, which indicates a higher degree of their genetic homogeneity than in strains of the Far Eastern and Siberian subtypes. The level of differences in the genome of strains of the European subtype, depending on the region and the source of isolation, was analyzed. No relationship was found between the level of homology of nucleotide sequences of TBEV strains of the European subtype and the source of isolation. The proposed models for the evolution of TBE are described. The area of TBE of the European subtype in Eurasia is analyzed. The maps of the geographical distribution of the European subtype are presented. It shows the European subtype TBE is found in 14 regions of Russia. TBE of this subtype, as a rule, causes a disease with a milder course in comparison with TBE caused by a virus of the Far Eastern or Siberian subtypes. An analysis of the main vectors and reservoir hosts of the European subtype TBEV in Europe and in Siberia has been carried out. It is emphasized that in Eurasia the European TBEV circulates in territories that differ significantly in climatic conditions, relief, landscape, and characteristics of biotopes. However, analysis of scientific literature data showed that, despite these differences, it has a high degree of genome stability.
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Ticks and their epidemiological role in Slovakia: from the past till present. Biologia (Bratisl) 2021; 77:1575-1610. [PMID: 34548672 PMCID: PMC8446484 DOI: 10.1007/s11756-021-00845-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 07/06/2021] [Indexed: 01/26/2023]
Abstract
In Slovakia, 22 tick species have been found to occur to date. Among them, Ixodes ricinus, Dermacentor reticulatus, D. marginatus and marginally Haemaphysalis concinna, H. inermis and H. punctata have been identified as the species of public health relevance. Ticks in Slovakia were found to harbour and transmit zoonotic and/or potentially zoonotic agents such as tick-borne encephalitis virus (TBEV), spirochaetes of the Borrelia burgdorferi sensu lato (s.l.) complex, the relapsing fever sprirochaete Borrelia miyamotoi, bacteria belonging to the orders Rickettsiales (Rickettsia spp., Anaplasma phagocytophilum, Neoehrlichia mikurensis), Legionellales (Coxiella burnetii), and Thiotrichales (Francisella tularensis), and Babesia spp. parasites (order Piroplasmida). Ixodes ricinus is the principal vector of the largest variety of microorganisms including viruses, bacteria and piroplasms. TBEV, B. burgdorferi s.l., rickettsiae of the spotted fever group, C. burnetii and F. tularensis have been found to cause serious diseases in humans, whereas B. miyamotoi, A. phagocytophilum, N. mikurensis, Babesia microti, and B. venatorum pose lower or potential risk to humans. Distribution of TBEV has a focal character. During the last few decades, new tick-borne encephalitis (TBE) foci and their spread to new areas have been registered and TBE incidence rates have increased. Moreover, Slovakia reports the highest rates of alimentary TBE infections among the European countries. Lyme borreliosis (LB) spirochaetes are spread throughout the distribution range of I. ricinus. Incidence rates of LB have shown a slightly increasing trend since 2010. Only a few sporadic cases of human rickettsiosis, anaplasmosis and babesiosis have been confirmed thus far in Slovakia. The latest large outbreaks of Q fever and tularaemia were recorded in 1993 and 1967, respectively. Since then, a few human cases of Q fever have been reported almost each year. Changes in the epidemiological characteristics and clinical forms of tularaemia have been observed during the last few decades. Global changes and development of modern molecular tools led to the discovery and identification of emerging or new tick-borne microorganisms and symbionts with unknown zoonotic potential. In this review, we provide a historical overview of research on ticks and tick-borne pathogens in Slovakia with the most important milestones and recent findings, and outline future directions in the investigation of ticks as ectoparasites and vectors of zoonotic agents and in the study of tick-borne diseases.
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Borde JP, Kaier K, Hehn P, Matzarakis A, Frey S, Bestehorn M, Dobler G, Chitimia-Dobler L. The complex interplay of climate, TBEV vector dynamics and TBEV infection rates in ticks-Monitoring a natural TBEV focus in Germany, 2009-2018. PLoS One 2021; 16:e0244668. [PMID: 33411799 PMCID: PMC7790265 DOI: 10.1371/journal.pone.0244668] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 12/14/2020] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Tick-borne encephalitis (TBE) is the most important tick-borne viral disease in Eurasia and causes disease in humans and in a number of animals, among them dogs and horses. There is still no good correlation between tick numbers, weather conditions and human cases. There is the hypothesis that co-feeding due to simultaneous occurrence of larvae and nymphs may be a factor for the increased transmission of the virus in nature and for human disease. Based on long-term data from a natural TBEV focus, phylogenetic results and meteorological data we sought to challenge this hypothesis. METHODS Ticks from an identified TBE natural focus were sampled monthly from 04/2009 to 12/2018. Ticks were identified and pooled. Pools were tested by RT-qPCR. Positive pools were confirmed by virus isolation and/or sequencing of additional genes (E gene, NS2 gene). Temperature data such as the decadal (10-day) mean daily maximum air temperature (DMDMAT) were obtained from a nearby weather station and statistical correlations between tick occurrence and minimal infection rates (MIR) were calculated. RESULTS In the study period from 04/2009 to 12/2018 a total of 15,530 ticks (2,226 females, 2,268 males, 11,036 nymphs) were collected. The overall MIR in nymphs over the whole period was 77/15,530 (0.49%), ranging from 0.09% (2009) to 1.36% (2015). The overall MIR of female ticks was 0.76% (17/2,226 ticks), range 0.14% (2013) to 3.59% (2016). The overall MIR of males was 0.57% (13/2,268 ticks), range from 0.26% (2009) to 0.97% (2015). The number of nymphs was statistically associated with a later start of spring/vegetation period, indicated by the onset of forsythia flowering. CONCLUSION There was no particular correlation between DMDMAT dynamics in spring and/or autumn and the MIR of nymphs or adult ticks detected. However, there was a positive correlation between the number of nymphs and the number of reported human TBE cases in the following months, but not in the following year. The hypothesis of the importance of co-feeding of larvae and nymphs for the maintenance of transmission cycle of TBEV in nature is not supported by our findings.
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Affiliation(s)
- Johannes P. Borde
- Division of Infectious Diseases, Department of Medicine II, University of Freiburg Medical Center and Faculty of Medicine, Freiburg i.Br., Germany
- Praxis Dr. J. Borde / Gesundheitszentrum Oberkirch, Oberkirch, Germany
| | - Klaus Kaier
- Institute of Medical Biometry and Statistics, Faculty of Medicine and Medical Center – University of Freiburg, University of Freiburg, Freiburg, Germany
| | - Philip Hehn
- Institute of Medical Biometry and Statistics, Faculty of Medicine and Medical Center – University of Freiburg, University of Freiburg, Freiburg, Germany
| | - Andreas Matzarakis
- Research Centre Human Biometeorology, German Meteorological Service, Freiburg, Germany
| | - Stefan Frey
- Bundeswehr Institute of Microbiology, German National Reference Laboratory for TBEV, München, Germany
| | | | - Gerhard Dobler
- Bundeswehr Institute of Microbiology, German National Reference Laboratory for TBEV, München, Germany
- Parasitology Unit, University of Hohenheim, Stuttgart, Germany
| | - Lidia Chitimia-Dobler
- Bundeswehr Institute of Microbiology, German National Reference Laboratory for TBEV, München, Germany
- Parasitology Unit, University of Hohenheim, Stuttgart, Germany
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Abdiyeva K, Turebekov N, Yegemberdiyeva R, Dmitrovskiy A, Yeraliyeva L, Shapiyeva Z, Nurmakhanov T, Sansyzbayev Y, Froeschl G, Hoelscher M, Zinner J, Essbauer S, Frey S. Vectors, molecular epidemiology and phylogeny of TBEV in Kazakhstan and central Asia. Parasit Vectors 2020; 13:504. [PMID: 33023633 PMCID: PMC7539389 DOI: 10.1186/s13071-020-04362-1] [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: 03/17/2020] [Accepted: 09/15/2020] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND In the South of Kazakhstan, Almaty Oblast' (region) is endemic for tick-borne encephalitis, with 0.16-0.32 cases/100,000 population between 2016-2018. The purpose of this study was to determine the prevalence and circulating subtypes of tick-borne encephalitis virus (TBEV) in Almaty Oblast' and Kyzylorda Oblast'. METHODS In 2015 we investigated 2341 ticks from 7 sampling sites for the presence of TBEV. Ticks were pooled in 501 pools and isolated RNA was tested for the presence of TBEV by RT-qPCR. For the positive samples, the E gene was amplified, sequenced and a phylogenetic analysis was carried out. RESULTS A total of 48 pools were TBEV-positive by the RT-qPCR. TBEV-positive ticks were only detected in three districts of Almaty Oblast' and not in Kyzylorda Oblast'. The positive TBEV pools were found within Ixodes persulcatus, Haemaphysalis punctata and Dermacentor marginatus. These tick species prevailed only in Almaty Oblast' whereas in Kyzylorda Oblast' Hyalomma asiaticum and D. marginatus are endemic. The minimum infection rates (MIR) in the sampling sites were 4.4% in Talgar, 2.8% in Tekeli and 1.1% in Yenbekshikazakh, respectively. The phylogenetic analysis of the generated sequences indicates that TBEV strains found in Almaty Oblast' clusters in the Siberian subtype within two different clades. CONCLUSIONS We provided new data about the TBEV MIR in ticks in Almaty Oblast' and showed that TBEV clusters in the Siberian Subtype in two different clusters at the nucleotide level. These results indicate that there are different influences on the circulating TBEV strains in south-eastern Kazakhstan. These influences might be caused by different routes of the virus spread in ticks which might bring different genetic TBEV lineages to Kazakhstan. The new data about the virus distribution and vectors provided here will contribute to an improvement of monitoring of tick-borne infections and timely anti-epidemic measures in Kazakhstan.
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Affiliation(s)
- Karlygash Abdiyeva
- Center for International Health, Ludwig-Maximilians-Universität, Munich, Germany
- National Scientific Center for Highly Dangerous Infections, Almaty, Kazakhstan
| | - Nurkeldi Turebekov
- Center for International Health, Ludwig-Maximilians-Universität, Munich, Germany
- National Scientific Center for Highly Dangerous Infections, Almaty, Kazakhstan
| | | | | | | | - Zhanna Shapiyeva
- Scientific Practical Center of Sanitary Epidemiological Expertise and Monitoring, Almaty, Kazakhstan
| | - Talgat Nurmakhanov
- National Scientific Center for Highly Dangerous Infections, Almaty, Kazakhstan
| | - Yerlan Sansyzbayev
- National Scientific Center for Highly Dangerous Infections, Almaty, Kazakhstan
| | - Guenter Froeschl
- Center for International Health, Ludwig-Maximilians-Universität, Munich, Germany
- Division of Infectious Diseases and Tropical Medicine, University Hospital, LMU Munich, Munich, Germany
| | - Michael Hoelscher
- Division of Infectious Diseases and Tropical Medicine, University Hospital, LMU Munich, Munich, Germany
| | | | | | - Stefan Frey
- Institute of Microbiology, Munich, Germany
- present Address: Bundeswehr Research Institute for Protective Technologies and CBRN Protection, Munster, Germany
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Clark JJ, Gilray J, Orton RJ, Baird M, Wilkie G, Filipe ADS, Johnson N, McInnes CJ, Kohl A, Biek R. Population genomics of louping ill virus provide new insights into the evolution of tick-borne flaviviruses. PLoS Negl Trop Dis 2020; 14:e0008133. [PMID: 32925939 PMCID: PMC7515184 DOI: 10.1371/journal.pntd.0008133] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 09/24/2020] [Accepted: 08/07/2020] [Indexed: 12/30/2022] Open
Abstract
The emergence and spread of tick-borne arboviruses pose an increased challenge to human and animal health. In Europe this is demonstrated by the increasingly wide distribution of tick-borne encephalitis virus (TBEV, Flavivirus, Flaviviridae), which has recently been found in the United Kingdom (UK). However, much less is known about other tick-borne flaviviruses (TBFV), such as the closely related louping ill virus (LIV), an animal pathogen which is endemic to the UK and Ireland, but which has been detected in other parts of Europe including Scandinavia and Russia. The emergence and potential spatial overlap of these viruses necessitates improved understanding of LIV genomic diversity, geographic spread and evolutionary history. We sequenced a virus archive composed of 22 LIV isolates which had been sampled throughout the UK over a period of over 80 years. Combining this dataset with published virus sequences, we detected no sign of recombination and found low diversity and limited evidence for positive selection in the LIV genome. Phylogenetic analysis provided evidence of geographic clustering as well as long-distance movement, including movement events that appear recent. However, despite genomic data and an 80-year time span, we found that the data contained insufficient temporal signal to reliably estimate a molecular clock rate for LIV. Additional analyses revealed that this also applied to TBEV, albeit to a lesser extent, pointing to a general problem with phylogenetic dating for TBFV. The 22 LIV genomes generated during this study provide a more reliable LIV phylogeny, improving our knowledge of the evolution of tick-borne flaviviruses. Our inability to estimate a molecular clock rate for both LIV and TBEV suggests that temporal calibration of tick-borne flavivirus evolution should be interpreted with caution and highlight a unique aspect of these viruses which may be explained by their reliance on tick vectors. Tick-borne pathogens represent a major emerging threat to public health and in recent years have been expanding into new areas. LIV is a neglected virus endemic to the UK and Ireland (though it has been detected in Scandinavia and Russia) which is closely related to the major human pathogen TBEV, but predominantly causes disease in sheep and grouse. The recent detection of TBEV in the UK, which has also emerged elsewhere in Europe, requires more detailed understanding of the spread and sequence diversity of LIV. This could be important for diagnosis and vaccination, but also to improve our understanding of the evolution and emergence of these tick-borne viruses. Here we describe the sequencing of 22 LIV isolates which have been sampled from several host species across the past century. We have utilised this dataset to investigate the evolutionary pressures that LIV is subjected to and have explored the evolution of LIV using phylogenetic analysis. Crucially we were unable to estimate a reliable molecular clock rate for LIV and found that this problem also extends to a larger phylogeny of TBEV sequences. This work highlights a previously unknown caveat of tick-borne flavivirus evolutionary analysis which may be important for understanding the evolution of these important pathogens.
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Affiliation(s)
- Jordan J. Clark
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
- Moredun Research Institute, Edinburgh, United Kingdom
- * E-mail: (JC); (RB)
| | - Janice Gilray
- Moredun Research Institute, Edinburgh, United Kingdom
| | - Richard J. Orton
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Margaret Baird
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Gavin Wilkie
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Ana da Silva Filipe
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Nicholas Johnson
- Animal and Plant Health Agency, Addlestone, Surrey, United Kingdom
- Faculty of Health and Medical Science, University of Surrey, Guildford, Surrey, United Kingdom
| | | | - Alain Kohl
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Roman Biek
- Institute of Biodiversity, Animal Health and Comparative Medicine - University of Glasgow, Glasgow, United Kingdom
- * E-mail: (JC); (RB)
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11
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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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12
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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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13
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First Isolation and Phylogenetic Analyses of Tick-Borne Encephalitis Virus in Lower Saxony, Germany. Viruses 2019; 11:v11050462. [PMID: 31117224 PMCID: PMC6563265 DOI: 10.3390/v11050462] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 05/16/2019] [Accepted: 05/18/2019] [Indexed: 12/30/2022] Open
Abstract
Tick-borne encephalitis (TBE) is the most important tick-borne arboviral disease in Europe. Presently, the main endemic regions in Germany are located in the southern half of the country. Although recently, sporadic human TBE cases were reported outside of these known endemic regions. The detection and characterization of invading TBE virus (TBEV) strains will considerably facilitate the surveillance and assessment of this important disease. In 2018, ticks were collected by flagging in several locations of the German federal state of Lower Saxony where TBEV-infections in humans (diagnosed clinical TBE disease or detection of TBEV antibodies) were reported previously. Ticks were pooled according to their developmental stage and tested for TBEV-RNA by RT-qPCR. Five of 730 (0.68%) pools from Ixodes spp. ticks collected in the areas of “Rauher Busch” and “Barsinghausen/Mooshuette” were found positive for TBEV-RNA. Phylogenetic analysis of the whole genomes and E gene sequences revealed a close relationship between the two TBEV isolates, which cluster with a TBEV strain from Poland isolated in 1971. This study provides first data on the phylogeny of TBEV in the German federal state of Lower Saxony, outside of the known TBE endemic areas of Germany. Our results support the hypothesis of an east-west invasion of TBEV strains in Western Europe.
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14
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Repeated isolation of tick-borne encephalitis virus from adult Dermacentor reticulatus ticks in an endemic area in Germany. Parasit Vectors 2019; 12:90. [PMID: 30867015 PMCID: PMC6416925 DOI: 10.1186/s13071-019-3346-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 02/26/2019] [Indexed: 11/24/2022] Open
Abstract
Background Tick-borne encephalitis (TBE) virus is transmitted to humans and animals through tick bites and is thought to circulate in very strictly defined natural environments called natural foci. The most common tick serving as a vector for the TBE virus in central Europe is Ixodes ricinus; it is rarely found in other tick species and in Dermacentor reticulatus it has, so far, only been reported in Poland. Methods Between autumn 2016 and spring 2018 ticks were collected by the flagging method in a new TBE focus in the district of northern Saxony, Germany, outside the known risk areas as defined by the national Robert Koch Institute. Ticks were morphologically identified and tested in pools for the presence of TBE virus using a real-time RT-PCR. TBE virus from positive pools was isolated in A549 cells, and the E gene sequences were determined after conventional RT-PCR, followed by a phylogenetic comparison. Results TBE virus was detected in 11 pools, 9 times in flagged adults D. reticulatus (n = 1534; MIR: 0.59%, CI: 0.29–11.3%) and only twice in I. ricinus nymphs (n = 349; MIR: 0.57%, CI: 0.02–2.2%). All other ticks, I. ricinus males (n = 33), females (n = 30) and larvae (n = 58), as well as 5 I. inopinatus (2 females, 3 males) and 14 Haemaphysalis concinna (3 females, 11 nymphs), tested negative for TBE virus. TBE virus was not detected in I. ricinus during the summer, when D. reticulatus is not active. Sequence comparison of the entire E gene of the isolated virus strains resembled each other with only 3 nucleotide differences. The most closely related viral sequences belong to TBE virus strains from Poland and Neustadt an der Waldnaab (county of Neustadt an der Waldnaab, Bavaria), approximately 200 km east and 200 km south-west of the new focus, respectively. Conclusions TBE virus was found in northern Saxony, Germany, with similar MIRs in D. reticulatus and I. ricinus, indicating that D. reticulatus plays an equal role to I. ricinus in virus circulation when both tick species are sympatric.
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15
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Andersen NS, Bestehorn M, Chitimia-Dobler L, Kolmos HJ, Jensen PM, Dobler G, Skarphédinsson S. Phylogenetic characterization of tick-borne encephalitis virus from Bornholm, Denmark. Ticks Tick Borne Dis 2018; 10:533-539. [PMID: 30704909 DOI: 10.1016/j.ttbdis.2018.12.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 12/17/2018] [Accepted: 12/27/2018] [Indexed: 12/30/2022]
Abstract
The Danish island of Bornholm in the Baltic Sea has been known as a tick-borne encephalitis (TBE) natural focus for more than 60 years. TBE in humans is diagnosed on a regular basis either in inhabitants or tourists of the island. Other areas in Denmark have been suggested as possible risk areas of TBE. Despite the long-known endemicity on Bornholm and the possibility of the virus circulating in other areas, no data on the prevalences of TBE virus (TBEV) in ticks, or adequate molecular characterization and phylogenetic studies are available for the circulating TBEV strains. This study aimed to detect TBEV in ticks collected on the island of Bornholm and other possible risk areas, with the attempt to isolate the circulating viruses for molecular and phylogenetic analysis and confirm the presence of virus in the predicted risk areas. From 2014 to 2016, 9321 I. ricinus (nymphs, females, and males) were collected by flagging 31 locations in Denmark. The ticks were pooled and tested for TBEV by qPCR. The envelope gene of the detected TBE virus strains was amplified and sequenced by RT-PCR. After successful virus isolation, whole genome sequencing was performed. Phylogenetic analysis of the obtained sequences was done by the Maximum Likelihood method. One pool of 11 females and one pool of eight males from a total of 34 tick pools collected from the northwestern shore of lake Rubinsøen on Bornholm tested positive, resulting in a local estimated point prevalence of 0.6% [CI95% 0,1-1.85%] in this microfocus. We were not successful in confirming any other of the predicted TBEV-endemic areas. Alignment of the two complete E genes from Bornholm revealed identical sequences. Virus isolation and whole genome sequencing were succeeded from one of the positive samples. Phylogenetic analysis showed that the isolated virus had the closest phylogenetic relationship to TBEV sequences detected in Eastern and Central Europe.
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Affiliation(s)
- Nanna Skaarup Andersen
- Clinical Centre of Emerging and Vector-borne Infections, Odense University Hospital, Sdr. Boulevard 29, DK-5000, Odense C, Denmark; Research Unit of Clinical Microbiology, University of Southern Denmark, J.B. Winsløvsvej 21.2, DK-5000, Odense C, Denmark.
| | - Malena Bestehorn
- Parasitology Unit, Institute of Zoology, University of Hohenheim, Hans-Wolff-Strasse 34, DE-70955, Stuttgart, Germany; Bundeswehr Institute of Microbiology, Neuherbergstrasse 11, DE-80937, Munich, Germany; German Center of Infection Research (DZIF) Partner Munich, Neuherbergstrasse 11, DE-80937, Munich, Germany
| | - Lidia Chitimia-Dobler
- Parasitology Unit, Institute of Zoology, University of Hohenheim, Hans-Wolff-Strasse 34, DE-70955, Stuttgart, Germany; Bundeswehr Institute of Microbiology, Neuherbergstrasse 11, DE-80937, Munich, Germany; German Center of Infection Research (DZIF) Partner Munich, Neuherbergstrasse 11, DE-80937, Munich, Germany
| | - Hans Jørn Kolmos
- Research Unit of Clinical Microbiology, University of Southern Denmark, J.B. Winsløvsvej 21.2, DK-5000, Odense C, Denmark
| | - Per Moestrup Jensen
- Department of Plant- and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Copenhagen, Denmark
| | - Gerhard Dobler
- Parasitology Unit, Institute of Zoology, University of Hohenheim, Hans-Wolff-Strasse 34, DE-70955, Stuttgart, Germany; Bundeswehr Institute of Microbiology, Neuherbergstrasse 11, DE-80937, Munich, Germany; German Center of Infection Research (DZIF) Partner Munich, Neuherbergstrasse 11, DE-80937, Munich, Germany
| | - Sigurdur Skarphédinsson
- Clinical Centre of Emerging and Vector-borne Infections, Odense University Hospital, Sdr. Boulevard 29, DK-5000, Odense C, Denmark; Department of Infectious Diseases, Odense University Hospital, Sdr. Boulevard 29, DK-5000, Odense C, Denmark
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16
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Bestehorn M, Weigold S, Kern WV, Chitimia-Dobler L, Mackenstedt U, Dobler G, Borde JP. Phylogenetics of tick-borne encephalitis virus in endemic foci in the upper Rhine region in France and Germany. PLoS One 2018; 13:e0204790. [PMID: 30335778 PMCID: PMC6193627 DOI: 10.1371/journal.pone.0204790] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Accepted: 09/15/2018] [Indexed: 12/30/2022] Open
Abstract
Objective Tick-borne encephalitis (TBE) caused by the tick-borne encephalitis virus (TBEV) is the most important tick-borne arboviral disease in Europe and Asia. The Upper Rhine Valley is thought to be the very western border of TBEV distribution in Europe. The aim of our study was to identify natural foci and isolate TBEV from ticks, to determine the prevalence of TBEV in local tick populations and to study the phylogenetic relatedness of circulating TBEV strains in this region. Material and methods Ticks were collected between 2016, 2017 and 2018 by flagging. TBEV was isolated from collected ticks and phylogenetic analyses were performed. Minimal infection rates (MIR) of the collected ticks were calculated. Results At 12 sampling sites, a total of 4,064 Ixodes ticks were collected in 2016 and 2017 –(and one single collection 2018). 953 male, 856 female adult ticks and 2,255 nymphs were identified. The MIR rates were 0,17% (1/595) for Schiltach (Germany) and 0,11% (1/944) for Foret de la Robertsau (France), respectively. Overall, the three newly described TBEV strains, isolated in the years 2016 and 2017 from the Upper Rhine Valley have no close phylogenetic relation and show a genetic relationship with strains from eastern Europe. The 2018 TBEV strain from Aubachstrasse (Germany), however, is closely related to the TBEV found in Schiltach (Germany). Conclusion In conclusion, we demonstrate, to our knowledge for the first time, the phylogenetic relations of the newly isolated TBEV strains on both sides of the upper Rhine river.
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Affiliation(s)
- Malena Bestehorn
- Parasitology Unit, University of Hohenheim, D-Stuttgart, Germany
| | - Sebastian Weigold
- Division of Infectious Diseases, Department of Medicine II, University of Freiburg Medical Center and Faculty of Medicine, Freiburg i.Br., Germany
| | - Winfried V Kern
- Division of Infectious Diseases, Department of Medicine II, University of Freiburg Medical Center and Faculty of Medicine, Freiburg i.Br., Germany
| | - Lidia Chitimia-Dobler
- Parasitology Unit, University of Hohenheim, D-Stuttgart, Germany.,Bundeswehr Institute of Microbiology, German Center of Infection Research (DZIF) partner site Munich, Neuherbergstraße 11, München, Germany
| | - Ute Mackenstedt
- Parasitology Unit, University of Hohenheim, D-Stuttgart, Germany
| | - Gerhard Dobler
- Parasitology Unit, University of Hohenheim, D-Stuttgart, Germany.,Bundeswehr Institute of Microbiology, German Center of Infection Research (DZIF) partner site Munich, Neuherbergstraße 11, München, Germany
| | - Johannes P Borde
- Division of Infectious Diseases, Department of Medicine II, University of Freiburg Medical Center and Faculty of Medicine, Freiburg i.Br., Germany.,Praxis Dr. J. Borde / Gesundheitszentrum Oberkirch, Am Marktplatz 8, Oberkirch, Germany
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17
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Andersen NS, Larsen SL, Olesen CR, Stiasny K, Kolmos HJ, Jensen PM, Skarphédinsson S. Continued expansion of tick-borne pathogens: Tick-borne encephalitis virus complex and Anaplasma phagocytophilum in Denmark. Ticks Tick Borne Dis 2018; 10:115-123. [PMID: 30245088 DOI: 10.1016/j.ttbdis.2018.09.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Revised: 08/30/2018] [Accepted: 09/13/2018] [Indexed: 12/21/2022]
Abstract
Tick-borne encephalitis virus (TBEV) is a tick-transmitted flavivirus within the tick-borne encephalitis (TBE) complex. The TBE complex is represented by both TBEV and louping ill virus (LIV) in Denmark. Anaplasma phagocytophilum is also transmitted by ticks and is believed to play an essential role in facilitating and aggravating LIV infection in sheep. This study aimed to describe the distribution of TBE complex viruses in Denmark, to establish the possible emergence of new foci and their association with the distribution of A. phagocytophilum. We performed a nationwide seroprevalence study of TBE complex viruses using roe deer (Capreolus capreolus) as sentinels and determined the prevalence of A. phagocytophilum in roe deer. Danish hunters obtained blood samples from roe deer during the hunting season of 2013-14. The samples were examined for TBEV-specific antibodies by virus neutralization tests (NT). A. phagocytophilum infection was assessed by specific real-time-PCR. The overall seroprevalence of the TBE complex viruses in roe deer was 6.9% (51/736). The positive samples were primarily obtained from a known TBE endemic foci and risk areas identified in previous sentinel studies. However, new TBE complex risk areas were also identified. The overall prevalence of A. phagocytophilum was 94.0% (173 PCR-positive of 184 roe deer), which is twice the rate observed ten years ago. These results point to an expansion of these tick-borne diseases geographically and within reservoir populations and, therefore, rationalize the use of sentinel models to monitor changes in transmission of tick-borne diseases and development of new risk areas. We found no association between TBE complex-positive roe deer and the prevalence of A. phagocytophilum, as almost all roe deer were infected. Based on our findings we encourage health care providers to be attentive to tick-borne illnesses such as TBE when treating patients with compatible symptoms.
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Affiliation(s)
- Nanna Skaarup Andersen
- Clinical Centre for Emerging and Vector-borne Infections, Odense University Hospital, Sdr. Boulevard 29, DK-5000, Odense C, Denmark; Research Unit of Clinical Microbiology, University of Southern Denmark, J.B. Winsløvsvej 21.2, DK-5000, Odense C, Denmark.
| | - Sanne Løkkegaard Larsen
- Clinical Centre for Emerging and Vector-borne Infections, Odense University Hospital, Sdr. Boulevard 29, DK-5000, Odense C, Denmark; Research Unit of Clinical Microbiology, University of Southern Denmark, J.B. Winsløvsvej 21.2, DK-5000, Odense C, Denmark.
| | | | - Karin Stiasny
- Center for Virology, Medical University Vienna, Kinderspitalgasse 15, A-1090, Vienna, Austria.
| | - Hans Jørn Kolmos
- Research Unit of Clinical Microbiology, University of Southern Denmark, J.B. Winsløvsvej 21.2, DK-5000, Odense C, Denmark.
| | - Per Moestrup Jensen
- Department of Plant- and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Copenhagen, Denmark.
| | - Sigurdur Skarphédinsson
- Clinical Centre for Emerging and Vector-borne Infections, Odense University Hospital, Sdr. Boulevard 29, DK-5000, Odense C, Denmark; Department of Infectious diseases, Odense University Hospital, Sdr. Boulevard 29, DK-5000, Odense C, Denmark.
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18
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Brugger K, Walter M, Chitimia-Dobler L, Dobler G, Rubel F. Seasonal cycles of the TBE and Lyme borreliosis vector Ixodes ricinus modelled with time-lagged and interval-averaged predictors. EXPERIMENTAL & APPLIED ACAROLOGY 2017; 73:439-450. [PMID: 29181672 PMCID: PMC5727152 DOI: 10.1007/s10493-017-0197-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 11/17/2017] [Indexed: 05/15/2023]
Abstract
Ticks of the species Ixodes ricinus (L.) are the major vectors for tick-borne diseases in Europe. The aim of this study was to quantify the influence of environmental variables on the seasonal cycle of questing I. ricinus. Therefore, an 8-year time series of nymphal I. ricinus flagged at monthly intervals in Haselmühl (Germany) was compiled. For the first time, cross correlation maps were applied to identify optimal associations between observed nymphal I. ricinus densities and time-lagged as well as temporal averaged explanatory variables. To prove the explanatory power of these associations, two Poisson regression models were generated. The first model simulates the ticks of the entire time series flagged per 100 m[Formula: see text], the second model the mean seasonal cycle. Explanatory variables comprise the temperature of the flagging month, the relative humidity averaged from the flagging month and 1 month prior to flagging, the temperature averaged over 4-6 months prior to the flagging event and the hunting statistics of the European hare from the preceding year. The first model explains 65% of the monthly tick variance and results in a root mean square error (RMSE) of 17 ticks per 100 m[Formula: see text]. The second model explains 96% of the tick variance. Again, the accuracy is expressed by the RMSE, which is 5 ticks per 100 m[Formula: see text]. As a major result, this study demonstrates that tick densities are higher correlated with time-lagged and temporal averaged variables than with contemporaneous explanatory variables, resulting in a better model performance.
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Affiliation(s)
- Katharina Brugger
- Institute for Veterinary Public Health, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210, Vienna, Austria.
| | - Melanie Walter
- Institute for Veterinary Public Health, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210, Vienna, Austria
| | - Lidia Chitimia-Dobler
- Bundeswehr Institute of Microbiology, Neuherbergstraße 11, 80937, Munich, Germany
- German Center of Infection Research (DZIF) Partner Site Munich, Munich, Germany
| | - Gerhard Dobler
- Bundeswehr Institute of Microbiology, Neuherbergstraße 11, 80937, Munich, Germany
- German Center of Infection Research (DZIF) Partner Site Munich, Munich, Germany
- Parasitology Unit, University of Hohenheim, Emil-Wolff-Straße 34, 70593, Stuttgart, Germany
| | - Franz Rubel
- Institute for Veterinary Public Health, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210, Vienna, Austria
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19
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Asghar N, Pettersson JHO, Dinnetz P, Andreassen Å, Johansson M. Deep sequencing analysis of tick-borne encephalitis virus from questing ticks at natural foci reveals similarities between quasispecies pools of the virus. J Gen Virol 2017; 98:413-421. [PMID: 28073402 PMCID: PMC5797951 DOI: 10.1099/jgv.0.000704] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Every year, tick-borne encephalitis virus (TBEV) causes severe central nervous system infection in 10 000 to 15 000 people in Europe and Asia. TBEV is maintained in the environment by an enzootic cycle that requires a tick vector and a vertebrate host, and the adaptation of TBEV to vertebrate and invertebrate environments is essential for TBEV persistence in nature. This adaptation is facilitated by the error-prone nature of the virus’s RNA-dependent RNA polymerase, which generates genetically distinct virus variants called quasispecies. TBEV shows a focal geographical distribution pattern where each focus represents a TBEV hotspot. Here, we sequenced and characterized two TBEV genomes, JP-296 and JP-554, from questing Ixodes ricinus ticks at a TBEV focus in central Sweden. Phylogenetic analysis showed geographical clustering among the newly sequenced strains and three previously sequenced Scandinavian strains, Toro-2003, Saringe-2009 and Mandal-2009, which originated from the same ancestor. Among these five Scandinavian TBEV strains, only Mandal-2009 showed a large deletion within the 3′ non-coding region (NCR), similar to the highly virulent TBEV strain Hypr. Deep sequencing of JP-296, JP-554 and Mandal-2009 revealed significantly high quasispecies diversity for JP-296 and JP-554, with intact 3′NCRs, compared to the low diversity in Mandal-2009, with a truncated 3′NCR. Single-nucleotide polymorphism analysis showed that 40 % of the single-nucleotide polymorphisms were common between quasispecies populations of JP-296 and JP-554, indicating a putative mechanism for how TBEV persists and is maintained within its natural foci.
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Affiliation(s)
- Naveed Asghar
- School of Natural Science, Technology & Environmental Studies, Södertörn University, Huddinge, Sweden.,School of Medical Sciences, Örebro University, Örebro, Sweden.,iRiSC - Inflammatory Response and Infection Susceptibility Centre, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - John H-O Pettersson
- Department of Infectious Disease Epidemiology and Modelling, Norwegian Institute of Public Health, Oslo, Norway.,Department of Microbiology, National Veterinary Institute, Uppsala, Sweden.,Department of Medical Biochemistry and Microbiology (IMBIM), Zoonosis Science Center, Uppsala University, Uppsala, Sweden
| | - Patrik Dinnetz
- School of Natural Science, Technology & Environmental Studies, Södertörn University, Huddinge, Sweden
| | - Åshild Andreassen
- Department of Virology, Division of Infectious Disease Control, Norwegian Institute of Public Health, Oslo, Norway
| | - Magnus Johansson
- School of Medical Sciences, Örebro University, Örebro, Sweden.,iRiSC - Inflammatory Response and Infection Susceptibility Centre, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
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20
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Bertrand YJK, Johansson M, Norberg P. Revisiting Recombination Signal in the Tick-Borne Encephalitis Virus: A Simulation Approach. PLoS One 2016; 11:e0164435. [PMID: 27760182 PMCID: PMC5070875 DOI: 10.1371/journal.pone.0164435] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 09/26/2016] [Indexed: 12/02/2022] Open
Abstract
The hypothesis of wide spread reticulate evolution in Tick-Borne Encephalitis virus (TBEV) has recently gained momentum with several publications describing past recombination events involving various TBEV clades. Despite a large body of work, no consensus has yet emerged on TBEV evolutionary dynamics. Understanding the occurrence and frequency of recombination in TBEV bears significant impact on epidemiology, evolution, and vaccination with live vaccines. In this study, we investigated the possibility of detecting recombination events in TBEV by simulating recombinations at several locations on the virus' phylogenetic tree and for different lengths of recombining fragments. We derived estimations of rates of true and false positive for the detection of past recombination events for seven recombination detection algorithms. Our analytical framework can be applied to any investigation dealing with the difficult task of distinguishing genuine recombination signal from background noise. Our results suggest that the problem of false positives associated with low detection P-values in TBEV, is more insidious than generally acknowledged. We reappraised the recombination signals present in the empirical data, and showed that reliable signals could only be obtained in a few cases when highly genetically divergent strains were involved, whereas false positives were common among genetically similar strains. We thus conclude that recombination among wild-type TBEV strains may occur, which has potential implications for vaccination with live vaccines, but that these events are surprisingly rare.
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Affiliation(s)
- Yann J. K. Bertrand
- Science and Historical Investigations of Evolution Laboratory of Dubá, Dubá, Czech Rep
| | - Magnus Johansson
- School of Medical Sciences Örebro University, Örebro, Sweden
- School of Natural Science, Technology & Environmental Studies, Södertörn University, Huddinge, Sweden
- iRiSC - Inflammatory Response and Infection Susceptibility Centre, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - Peter Norberg
- Department of Clinical Microbiology, Sahlgrenska University, Gothenburg, Sweden
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21
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Transmission and evolution of tick-borne viruses. Curr Opin Virol 2016; 21:67-74. [PMID: 27569396 DOI: 10.1016/j.coviro.2016.08.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 08/08/2016] [Accepted: 08/09/2016] [Indexed: 02/05/2023]
Abstract
Ticks transmit a diverse array of viruses such as tick-borne encephalitis virus, Powassan virus, and Crimean-Congo hemorrhagic fever virus that are reemerging in many parts of the world. Most tick-borne viruses (TBVs) are RNA viruses that replicate using error-prone polymerases and produce genetically diverse viral populations that facilitate their rapid evolution and adaptation to novel environments. This article reviews the mechanisms of virus transmission by tick vectors, the molecular evolution of TBVs circulating in nature, and the processes shaping viral diversity within hosts to better understand how these viruses may become public health threats. In addition, remaining questions and future directions for research are discussed.
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22
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Kovalev SY, Mukhacheva TA. Baltic lineage of tick-borne encephalitis virus: A putative evolutionary pathway. Ticks Tick Borne Dis 2016; 7:1209-1215. [PMID: 27478072 DOI: 10.1016/j.ttbdis.2016.07.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 06/20/2016] [Accepted: 07/22/2016] [Indexed: 10/21/2022]
Abstract
Tick-borne encephalitis virus (TBEV) is transmitted by ixodid ticks and has three subtypes. The most genetically heterogeneous and widely distributed is the Siberian subtype which is subdivided into two main phylogenetic lineages, Asian (TBEV-SibAsia) and Baltic (TBEV-SibBaltic). According to the hypothesis of quantum evolution of TBEV (Kovalev et al., 2014b), TBEV-SibAsia originated about 370 years ago in Siberia, but the question concerning the time and place of origin of TBEV-SibBaltic is still to be solved. In the present paper, the sequences of a gene E fragment of 20 newly obtained TBEV-SibBaltic strains and 164 sequences of TBEV-SibBaltic from GenBank were analysed. The clusteron approach applied to TBEV-SibBaltic allowed the identification of three new clusterons. We revealed three clades of TBEV-SibBaltic, each characterized by a certain geographical distribution, and estimated their evolutionary ages. The oldest clade was Balt I, which presumably originated in North-West Russia and the Baltic countries about 300 years ago as a result of human activity, and then gave rise to the other clades in the Urals and West Siberia. The European subtype of TBEV and TBEV-SibBaltic may have originated simultaneously from the clusteron-founder 3A of TBEV-SibAsia, the former through the adaptation of the virus to Ixodes ricinus, the latter - to a European subpopulation of Ixodes persulcatus. The use of the clusteron approach complemented with the results of phylogenetic analysis, data on the geographical distribution of the virus, the population structure of ticks, and the historical evidence allow us to estimate evolutionary pathways of the subtypes and phylogenetic lineages of TBEV.
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Affiliation(s)
- S Y Kovalev
- Laboratory of Molecular Genetics, Institute of Natural Sciences, Ural Federal University, Yekaterinburg, Russia.
| | - T A Mukhacheva
- Laboratory of Molecular Genetics, Institute of Natural Sciences, Ural Federal University, Yekaterinburg, Russia
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23
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Kunze U. Tick-borne encephalitis as a notifiable disease − Status quo and the way forward. Report of the 17th annual meeting of the International Scientific Working Group on Tick-Borne Encephalitis (ISW-TBE). Ticks Tick Borne Dis 2015; 6:545-8. [DOI: 10.1016/j.ttbdis.2015.04.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 04/15/2015] [Indexed: 11/29/2022]
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24
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Heinz FX, Stiasny K, Holzmann H, Kundi M, Sixl W, Wenk M, Kainz W, Essl A, Kunz C. Emergence of tick-borne encephalitis in new endemic areas in Austria: 42 years of surveillance. ACTA ACUST UNITED AC 2015; 20:9-16. [PMID: 25860391 DOI: 10.2807/1560-7917.es2015.20.13.21077] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Human infections with tick-borne encephalitis (TBE)virus are a public health concern in certain regions of Europe, central and eastern Asia. Expansions of endemic areas and increased incidences have been associated with different factors including ecological changes supporting tick reproduction, socioeconomic changes increasing human outdoor activities and climatic changes favouring virus circulation in natural foci. Austria is among the most strongly affected countries in Central Europe, but the annual number of cases has strongly declined due to vaccination. Here,we have analysed changes of the incidence of TBE in the unvaccinated population of all federal states of Austria over a period of 42 years. The overall incidence in Austria has remained constant, but new strongly affected endemic regions have emerged in alpine valleys in the west of Austria. In parallel, the incidence in low-land regions in the north-east of the country is decreasing. There is no evidence for a shift to higher altitudes of infection sites in the traditional TBE zones,but the average altitudes of some newly established endemic areas in the west are significantly higher. Our analyses underscore the focal nature of TBE endemic areas and the potential of TBE virus to emerge in previously unaffected regions.
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Affiliation(s)
- F X Heinz
- Department of Virology, Medical University of Vienna, Vienna, Austria
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25
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Formanová P, Černý J, Bolfíková BČ, Valdés JJ, Kozlova I, Dzhioev Y, Růžek D. Full genome sequences and molecular characterization of tick-borne encephalitis virus strains isolated from human patients. Ticks Tick Borne Dis 2014; 6:38-46. [PMID: 25311899 DOI: 10.1016/j.ttbdis.2014.09.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 09/05/2014] [Accepted: 09/05/2014] [Indexed: 12/30/2022]
Abstract
Tick-borne encephalitis virus (TBEV) causes tick-borne encephalitis (TBE), one of the most important human neuroinfections across Eurasia. Up to date, only three full genome sequences of human European TBEV isolates are available, mostly due to difficulties with isolation of the virus from human patients. Here we present full genome characterization of an additional five low-passage TBEV strains isolated from human patients with severe forms of TBE. These strains were isolated in 1953 within Central Bohemia in the former Czechoslovakia, and belong to the historically oldest human TBEV isolates in Europe. We demonstrate here that all analyzed isolates are distantly phylogenetically related, indicating that the emergence of TBE in Central Europe was not caused by one predominant strain, but rather a pool of distantly related TBEV strains. Nucleotide identity between individual sequenced TBEV strains ranged from 97.5% to 99.6% and all strains shared large deletions in the 3' non-coding region, which has been recently suggested to be an important determinant of virulence. The number of unique amino acid substitutions varied from 3 to 9 in individual isolates, but no characteristic amino acid substitution typical exclusively for all human TBEV isolates was identified when compared to the isolates from ticks. We did, however, correlate that the exploration of the TBEV envelope glycoprotein by specific antibodies were in close proximity to these unique amino acid substitutions. Taken together, we report here the largest number of patient-derived European TBEV full genome sequences to date and provide a platform for further studies on evolution of TBEV since the first emergence of human TBE in Europe.
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Affiliation(s)
- Petra Formanová
- Department of Virology, Veterinary Research Institute, Hudcova 70, CZ-62100 Brno, Czech Republic; Faculty of Science, Masaryk University, Kotlářská 267/2, CZ-61137 Brno, Czech Republic
| | - Jiří Černý
- Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, Branišovská 31, CZ-37005 České Budějovice, Czech Republic; Faculty of Science, University of South Bohemia, Branišovská 31, CZ-37005 České Budějovice, Czech Republic
| | - Barbora Černá Bolfíková
- Faculty of Tropical AgriSciences, Czech University of Life Sciences Prague, Kamýcká 126, CZ-16521 Prague, Czech Republic
| | - James J Valdés
- Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, Branišovská 31, CZ-37005 České Budějovice, Czech Republic
| | - Irina Kozlova
- Institute of Biomedical Technology, Irkutsk State Medical University of Russian Ministry of Health, Krasnogo Vosstanija 1, Irkutsk 664003, Russia; FSSFE Scientific Centre of Family Health and Human Reproduction Problems, Siberian Branch of the Russian Academy of Medical Sciences, Timirjazeva Street 16, 664003 Irkutsk, Russia
| | - Yuri Dzhioev
- Institute of Biomedical Technology, Irkutsk State Medical University of Russian Ministry of Health, Krasnogo Vosstanija 1, Irkutsk 664003, Russia; FSSFE Scientific Centre of Family Health and Human Reproduction Problems, Siberian Branch of the Russian Academy of Medical Sciences, Timirjazeva Street 16, 664003 Irkutsk, Russia
| | - Daniel Růžek
- Department of Virology, Veterinary Research Institute, Hudcova 70, CZ-62100 Brno, Czech Republic; Faculty of Science, Masaryk University, Kotlářská 267/2, CZ-61137 Brno, Czech Republic; Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, Branišovská 31, CZ-37005 České Budějovice, Czech Republic; Faculty of Science, University of South Bohemia, Branišovská 31, CZ-37005 České Budějovice, Czech Republic.
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26
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Rieille N, Bressanelli S, Freire CCM, Arcioni S, Gern L, Péter O, Voordouw MJ. Prevalence and phylogenetic analysis of tick-borne encephalitis virus (TBEV) in field-collected ticks (Ixodes ricinus) in southern Switzerland. Parasit Vectors 2014; 7:443. [PMID: 25245773 PMCID: PMC4261884 DOI: 10.1186/1756-3305-7-443] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 09/13/2014] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Tick-borne encephalitis is the most common tick-borne viral infection in Europe with 3,000 human cases reported each year. In Western Europe, the castor bean tick, Ixodes ricinus, is the principal vector of the tick-borne encephalitis virus (TBEV). TBEV appears to be spreading geographically and was recently detected for the first time in Canton Valais in the southern part of Switzerland. The purpose of the present study was to survey the I. ricinus tick populations of Canton Valais for TBEV. METHODS We collected a total of 19,331 I. ricinus ticks at 45 different sites in Canton Valais between 2010 and 2013. Ticks were processed in pools and tested for TBEV using reverse transcription quantitative PCR. The NS5 gene and the envelope gene of the TBEV isolates were partially sequenced for phylogenetic analysis. RESULTS TBEV was detected in tick populations at six of the 45 sites. These six sites were all located in a 33 km transect along the Rhône River. TBEV was detected in two sites for three of the four years of the study showing the temporal persistence of the pathogen. Prevalence of TBEV in the six positive sites ranged from 0.16% to 11.11%. Phylogenetic analysis found that all TBEV isolates from Canton Valais belonged to the European subtype. Genetic analysis found two distinct lineages of TBEV suggesting that Canton Valais experienced two independent colonization events. CONCLUSIONS TBEV appears to be well established at certain locations in Canton Valais.
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Affiliation(s)
- Nadia Rieille
- />Central Institute of Valais Hospitals, Infectious diseases, Av Grand Champsec 86, Sion, Switzerland
- />Laboratory of Ecology and Evolution of Parasites, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000 Neuchâtel, Switzerland
| | - Stéphane Bressanelli
- />Laboratoire de Virologie Moléculaire et Structurale, CNRS UPR3296, 1 avenue de la Terrasse, 91198 Gif-sur-Yvette cedex, France
| | - Caio C M Freire
- />Inter-institutional Grad Program on Bioinformatics, University of Sao Paulo, Matao Street 1010, Sao Paulo, Brazil
| | - Séverine Arcioni
- />Central Institute of Valais Hospitals, Genetics, Av Grand Champsec 86, Sion, Switzerland
| | - Lise Gern
- />Laboratory of Eco-Epidemiology of Parasites, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000 Neuchâtel, Switzerland
| | - Olivier Péter
- />Central Institute of Valais Hospitals, Infectious diseases, Av Grand Champsec 86, Sion, Switzerland
| | - Maarten J Voordouw
- />Laboratory of Ecology and Evolution of Parasites, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000 Neuchâtel, Switzerland
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27
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Pettersson JHO, Fiz-Palacios O. Dating the origin of the genus Flavivirus in the light of Beringian biogeography. J Gen Virol 2014; 95:1969-1982. [PMID: 24914065 DOI: 10.1099/vir.0.065227-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The genus Flavivirus includes some of the most important human viral pathogens, and its members are found in all parts of the populated world. The temporal origin of diversification of the genus has long been debated due to the inherent problems with dating deep RNA virus evolution. A generally accepted hypothesis suggests that Flavivirus emerged within the last 10 000 years. However, it has been argued that the tick-borne Powassan flavivirus was introduced into North America some time between the opening and closing of the Beringian land bridge that connected Asia and North America 15 000-11 000 years ago, indicating an even older origin for Flavivirus. To determine the temporal origin of Flavivirus, we performed Bayesian relaxed molecular clock dating on a dataset with high coverage of the presently available Flavivirus diversity by combining tip date calibrations and internal node calibration, based on the Powassan virus and Beringian land bridge biogeographical event. Our analysis suggested that Flavivirus originated ~85 000 (64 000-110 000) or 120 000 (87 000-159 000) years ago, depending on the circumscription of the genus. This is significantly older than estimated previously. In light of our results, we propose that it is likely that modern humans came in contact with several members of the genus Flavivirus much earlier than suggested previously, and that it is possible that the spread of several flaviviruses coincided with, and was facilitated by, the migration and population expansion of modern humans out of Africa.
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Affiliation(s)
- John H-O Pettersson
- Department of Systematic Biology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Omar Fiz-Palacios
- Department of Systematic Biology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
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28
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A tick-borne segmented RNA virus contains genome segments derived from unsegmented viral ancestors. Proc Natl Acad Sci U S A 2014; 111:6744-9. [PMID: 24753611 DOI: 10.1073/pnas.1324194111] [Citation(s) in RCA: 146] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Although segmented and unsegmented RNA viruses are commonplace, the evolutionary links between these two very different forms of genome organization are unclear. We report the discovery and characterization of a tick-borne virus--Jingmen tick virus (JMTV)--that reveals an unexpected connection between segmented and unsegmented RNA viruses. The JMTV genome comprises four segments, two of which are related to the nonstructural protein genes of the genus Flavivirus (family Flaviviridae), whereas the remaining segments are unique to this virus, have no known homologs, and contain a number of features indicative of structural protein genes. Remarkably, homology searching revealed that sequences related to JMTV were present in the cDNA library from Toxocara canis (dog roundworm; Nematoda), and that shared strong sequence and structural resemblances. Epidemiological studies showed that JMTV is distributed in tick populations across China, especially Rhipicephalus and Haemaphysalis spp., and experiences frequent host-switching and genomic reassortment. To our knowledge, JMTV is the first example of a segmented RNA virus with a genome derived in part from unsegmented viral ancestors.
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29
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Karan LS, Ciccozzi M, Yakimenko VV, Presti AL, Cella E, Zehender G, Rezza G, Platonov AE. The deduced evolution history of Omsk hemorrhagic fever virus. J Med Virol 2013; 86:1181-7. [DOI: 10.1002/jmv.23856] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/29/2013] [Indexed: 02/03/2023]
Affiliation(s)
| | - Massimo Ciccozzi
- Department of Infectious; Parasitic and Immunomediated Diseases; National Institute of Health; Rome Italy
| | | | - Alessandra Lo Presti
- Department of Infectious; Parasitic and Immunomediated Diseases; National Institute of Health; Rome Italy
| | - Eleonora Cella
- Department of Infectious; Parasitic and Immunomediated Diseases; National Institute of Health; Rome Italy
| | - Gianguglielmo Zehender
- Department of Biomedical and Clinical Sciences; L. Sacco Hospital; University of Milan; Milan Italy
| | - Giovanni Rezza
- Department of Infectious; Parasitic and Immunomediated Diseases; National Institute of Health; Rome Italy
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30
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Frey S, Essbauer S, Zöller G, Klempa B, Weidmann M, Dobler G, Pfeffer M. Complete Genome Sequence of Tick-Borne Encephalitis Virus Strain A104 Isolated from a Yellow-Necked Mouse (Apodemus flavicollis) in Austria. GENOME ANNOUNCEMENTS 2013; 1:e00564-13. [PMID: 23929473 PMCID: PMC3738889 DOI: 10.1128/genomea.00564-13] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 07/08/2013] [Indexed: 11/20/2022]
Abstract
Tick-borne encephalitis virus (TBEV) strain A104 was isolated from the brain of a yellow-necked mouse in Austria in 1990. The complete genome sequence was 11,097 nucleotides long. Comparison with TBEV prototype strain Neudoerfl showed 32 amino acid exchanges and the absence of an internal poly(A) stretch within the 3' noncoding region.
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Affiliation(s)
- Stefan Frey
- Bundeswehr Institute of Microbiology, Munich, Germany
| | | | - Gudrun Zöller
- Bundeswehr Institute of Microbiology, Munich, Germany
| | - Boris Klempa
- Institute of Virology, Slovak Academy of Science, Bratislava, Slovakia
- Institute of Medical Virology, Helmut-Ruska-Haus, Charité University Hospital, Berlin, Germany
| | - Manfred Weidmann
- Department of Virology, University Medical Center Göttingen, Göttingen, Germany
| | | | - Martin Pfeffer
- Bundeswehr Institute of Microbiology, Munich, Germany
- Institute of Animal Hygiene and Veterinary Public Health, University of Leipzig, Leipzig, Germany
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