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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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Omazic A, Han S, Albihn A, Ullman K, Choklikitumnuey P, Perissinotto D, Grandi G. Ixodid tick species found in northern Sweden - Data from a frontier area. Ticks Tick Borne Dis 2023; 14:102244. [PMID: 37611507 DOI: 10.1016/j.ttbdis.2023.102244] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 08/11/2023] [Accepted: 08/13/2023] [Indexed: 08/25/2023]
Abstract
Environmental and climatic changes in northern Europe have shaped a geographical area in which new tick species may become established and introduce new tick-borne pathogens. In recent decades, ticks have expanded their latitudinal and altitudinal range limits in northern Sweden. In this study, ticks were collected in 2018 and 2019 in northern Sweden from different hosts, mainly from dogs, cats and humans. The ticks in 2018 (n = 2141, collected from 65 municipalities in 11 provinces) were identified as Ixodes ricinus (n = 2108, 98.5%), Ixodes persulcatus (n = 18, 0.8%), Ixodes trianguliceps (n = 14, 0.7%) and Hyalomma marginatum (n = 1, 0.05%). The ticks collected in 2019 (n = 519, across a smaller area than in 2018, i.e. Sweden's four northernmost provinces) were identified as I. ricinus (n = 242, 46.6%) and I. persulcatus (n = 277, 53.4%). Among those collected in 2019, the majority of I. ricinus (n = 111, 45.9%) were submitted from the province of Västerbotten, while most I. persulcatus (n = 259, 93.5%) were collected in the province of Norrbotten. This study provides updated figures on the geographical distribution of two Ixodes species in northern Sweden. The results confirmed I. ricinus to be the dominant species and that I. persulcatus has enlarged its distributional area compared with previous reports. Updated knowledge of tick distribution is fundamental for the creation of risk maps and will allow relevant advice to be provided to the general public, suggesting measures to prevent tick bites and consequently tick-borne diseases.
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Affiliation(s)
- Anna Omazic
- Department of Chemistry, Environment and Feed Hygiene, National Veterinary Institute (SVA), Uppsala SE-751 89, Sweden.
| | - Seungeun Han
- Department of Epidemiology and Disease Control, National Veterinary Institute (SVA), Uppsala SE-751 89, Sweden
| | - Ann Albihn
- Department of Epidemiology and Disease Control, National Veterinary Institute (SVA), Uppsala SE-751 89, Sweden; Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Karin Ullman
- Department of Microbiology, National Veterinary Institute (SVA), Uppsala SE-751 89, Sweden
| | - Phimphanit Choklikitumnuey
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Debora Perissinotto
- Department of Microbiology, National Veterinary Institute (SVA), Uppsala SE-751 89, Sweden
| | - Giulio Grandi
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden; Department of Microbiology, National Veterinary Institute (SVA), Uppsala SE-751 89, Sweden
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Kjær LJ, Johansson M, Lindgren PE, Asghar N, Wilhelmsson P, Fredlund H, Christensson M, Wallenhammar A, Bødker R, Rasmussen G, Kjellander P. Potential drivers of human tick-borne encephalitis in the Örebro region of Sweden, 2010-2021. Sci Rep 2023; 13:7685. [PMID: 37169798 PMCID: PMC10175290 DOI: 10.1038/s41598-023-34675-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 05/05/2023] [Indexed: 05/13/2023] Open
Abstract
Incidence of tick-borne encephalitis (TBE) has increased during the last years in Scandinavia, but the underlying mechanism is not understood. TBE human case data reported between 2010 and 2021 were aggregated into postal codes within Örebro County, south-central Sweden, along with tick abundance and environmental data to analyse spatial patterns and identify drivers of TBE. We identified a substantial and continuing increase of TBE incidence in Örebro County during the study period. Spatial cluster analyses showed significant hotspots (higher number of cases than expected) in the southern and northern parts of Örebro County, whereas a cold spot (lower number of cases than expected) was found in the central part comprising Örebro municipality. Generalised linear models showed that the risk of acquiring TBE increased by 12.5% and 72.3% for every percent increase in relative humidity and proportion of wetland forest, respectively, whereas the risk decreased by 52.8% for every degree Celsius increase in annual temperature range. However, models had relatively low goodness of fit (R2 < 0.27). Results suggest that TBE in Örebro County is spatially clustered, however variables used in this study, i.e., climatic variables, forest cover, water, tick abundance, sheep as indicator species, alone do not explain this pattern.
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Affiliation(s)
- Lene Jung Kjær
- Section for Animal Welfare and Disease Control, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark.
| | - Magnus Johansson
- School of Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - Per-Eric Lindgren
- Division of Inflammation and Infection, Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
- Division of Clinical Microbiology, Department of Laboratory Medicine, Region Jönköping County, Jönköping, Sweden
| | - Naveed Asghar
- School of Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - Peter Wilhelmsson
- Division of Inflammation and Infection, Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
- Division of Clinical Microbiology, Department of Laboratory Medicine, Region Jönköping County, Jönköping, Sweden
| | - Hans Fredlund
- Department of Laboratory Medicine, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
- Örebro County Council, Örebro, Sweden
| | - Madeleine Christensson
- Grimsö Wildlife Research Station, Department of Ecology, Swedish University of Agricultural Sciences (SLU), Riddarhyttan, Sweden
| | - Amélie Wallenhammar
- School of Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - René Bødker
- Section for Animal Welfare and Disease Control, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Gunløg Rasmussen
- School of Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
- Örebro County Council, Örebro, Sweden
| | - Petter Kjellander
- Grimsö Wildlife Research Station, Department of Ecology, Swedish University of Agricultural Sciences (SLU), Riddarhyttan, Sweden
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Bugmyrin SV, Romanova LY, Belova OA, Kholodilov IS, Bespyatova LA, Chernokhaeva LL, Gmyl LV, Klimentov AS, Ivannikova AY, Polienko AE, Yakovlev AS, Ieshko EP, Gmyl AP, Karganova GG. Pathogens in Ixodes persulcatus and Ixodes ricinus ticks (Acari, Ixodidae) in Karelia (Russia). Ticks Tick Borne Dis 2022; 13:102045. [PMID: 36183587 DOI: 10.1016/j.ttbdis.2022.102045] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 08/23/2022] [Accepted: 09/14/2022] [Indexed: 11/23/2022]
Abstract
Ixodid ticks (Acarina, Ixodidae) are vectors of dangerous human infections. The main tick species that determine the epidemiological situation for tick-borne diseases in northern Europe are Ixodes ricinus and Ixodes persulcatus. In recent years, significant changes in the number and distribution of these species have been observed, accompanied by an expansion of the sympatric range. This work summarizes the data of long-term studies carried out in Karelia since 2007 on the infection of I. persulcatus and I. ricinus ticks with various pathogens, including new viruses with unclear pathogenic potential. As a result, tick-borne encephalitis virus (TBEV, Siberian genotype), Alongshan virus, several representatives of the family Phenuiviridae, Borrelia afzelii, Borrelia garinii, Ehrlichia muris, Candidatus Rickettsia tarasevichiae and Candidatus Lariskella arthropodarum were identified. Data were obtained on the geographical and temporal variability of tick infection rates with these main pathogens. The average infection rates of I. persulcatus with TBEV and Borrelia burgdorferi sensu lato were 4.4% and 23.4% and those of I. ricinus were 1.1% and 11.9%, respectively. We did not find a correlation between the infection rate of ticks with TBEV, B. burgdorferi s.l. and Ehrlichia muris/chaffeensis with the sex of the vector. In general, the peculiarities of the epidemiological situation in Karelia are determined by the wide distribution and high abundance of I. persulcatus ticks and by their relatively high infection rate with TBEV and B. burgdorferi s.l. in most of the territory, including the periphery of the range.
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Affiliation(s)
- S V Bugmyrin
- Institute of Biology, Karelian Research Centre, Russian Academy of Sciences, 11 Pushkinskaya St., Petrozavodsk 185910, Russia
| | - L Yu Romanova
- FSASI "Chumakov FSC R&D IBP RAS" (Institute of Poliomyelitis), prem. 8, k.17, pos. Institut Poliomyelita, poselenie Moskovskiy, Moscow 108811, Russia; Institute for Translational Medicine and Biotechnology, Sechenov University, Moscow 119146, Russia
| | - O A Belova
- FSASI "Chumakov FSC R&D IBP RAS" (Institute of Poliomyelitis), prem. 8, k.17, pos. Institut Poliomyelita, poselenie Moskovskiy, Moscow 108811, Russia
| | - I S Kholodilov
- FSASI "Chumakov FSC R&D IBP RAS" (Institute of Poliomyelitis), prem. 8, k.17, pos. Institut Poliomyelita, poselenie Moskovskiy, Moscow 108811, Russia
| | - L A Bespyatova
- Institute of Biology, Karelian Research Centre, Russian Academy of Sciences, 11 Pushkinskaya St., Petrozavodsk 185910, Russia
| | - L L Chernokhaeva
- FSASI "Chumakov FSC R&D IBP RAS" (Institute of Poliomyelitis), prem. 8, k.17, pos. Institut Poliomyelita, poselenie Moskovskiy, Moscow 108811, Russia
| | - L V Gmyl
- FSASI "Chumakov FSC R&D IBP RAS" (Institute of Poliomyelitis), prem. 8, k.17, pos. Institut Poliomyelita, poselenie Moskovskiy, Moscow 108811, Russia
| | - A S Klimentov
- FSASI "Chumakov FSC R&D IBP RAS" (Institute of Poliomyelitis), prem. 8, k.17, pos. Institut Poliomyelita, poselenie Moskovskiy, Moscow 108811, Russia
| | - A Y Ivannikova
- FSASI "Chumakov FSC R&D IBP RAS" (Institute of Poliomyelitis), prem. 8, k.17, pos. Institut Poliomyelita, poselenie Moskovskiy, Moscow 108811, Russia
| | - A E Polienko
- FSASI "Chumakov FSC R&D IBP RAS" (Institute of Poliomyelitis), prem. 8, k.17, pos. Institut Poliomyelita, poselenie Moskovskiy, Moscow 108811, Russia
| | - A S Yakovlev
- FSASI "Chumakov FSC R&D IBP RAS" (Institute of Poliomyelitis), prem. 8, k.17, pos. Institut Poliomyelita, poselenie Moskovskiy, Moscow 108811, Russia
| | - E P Ieshko
- Institute of Biology, Karelian Research Centre, Russian Academy of Sciences, 11 Pushkinskaya St., Petrozavodsk 185910, Russia
| | - A P Gmyl
- FSASI "Chumakov FSC R&D IBP RAS" (Institute of Poliomyelitis), prem. 8, k.17, pos. Institut Poliomyelita, poselenie Moskovskiy, Moscow 108811, Russia
| | - G G Karganova
- FSASI "Chumakov FSC R&D IBP RAS" (Institute of Poliomyelitis), prem. 8, k.17, pos. Institut Poliomyelita, poselenie Moskovskiy, Moscow 108811, Russia; Institute for Translational Medicine and Biotechnology, Sechenov University, Moscow 119146, Russia; Lomonosov Moscow State University, Department of Biology, Moscow 119991, Russia.
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Wondim MA, Czupryna P, Pancewicz S, Kruszewska E, Groth M, Moniuszko-Malinowska A. Epidemiological Trends of Trans-Boundary Tick-Borne Encephalitis in Europe, 2000-2019. Pathogens 2022; 11:pathogens11060704. [PMID: 35745558 PMCID: PMC9228375 DOI: 10.3390/pathogens11060704] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 06/01/2022] [Accepted: 06/14/2022] [Indexed: 02/04/2023] Open
Abstract
Tick-borne encephalitis is a neuroinfection widely distributed in the Euro-Asia region. Primarily, the virus is transmitted by the bite of infected ticks. From 2000-2019, the total number of confirmed cases in Europe reported to the European Centre for Disease Prevention and Control was 51,519. The number of cases decreased in 2014 and 2015; however, since 2015, a growing number of cases have been observed, with the involvement of countries in which TBE has not been previously reported. The determinant factors for the spread of TBE are host population size, weather conditions, movement of hosts, and local regulations on the socioeconomic dynamics of the local and travelling people around the foci areas. The mean incidence rate of tick-borne encephalitis from 2000-2019 in Europe was 3.27, while the age-adjusted mean incidence rate was 2.19 per 100,000 population size. This review used several articles and data sources from the European Centre for Diseases Prevention and Control.
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Dub T, Ollgren J, Huusko S, Uusitalo R, Siljander M, Vapalahti O, Sane J. Game Animal Density, Climate, and Tick-Borne Encephalitis in Finland, 2007-2017. Emerg Infect Dis 2020; 26:2899-2906. [PMID: 33219653 PMCID: PMC7706931 DOI: 10.3201/eid2612.191282] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [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
Tick-borne encephalitis (TBE) is an endemic infection of public health importance in Finland. We investigated the effect of ecologic factors on 2007-2017 TBE trends. We obtained domestic TBE case data from the National Infectious Diseases Register, weather data from the US National Oceanic and Atmospheric Administration, and data from the Natural Resources Institute in Finland on mammals killed by hunters yearly in game management areas. We performed a mixed-effects time-series analysis with time lags on weather and animal parameters, adding a random effect to game management areas. During 2007-2017, a total of 395/460 (86%) domestic TBE cases were reported with known place of exposure and date of sampling. Overall, TBE incidence increased yearly by 15%. After adjusting for the density of other animals and minimum temperatures, we found thatTBE incidence was positively associated with white-tailed deer density. Variation in host animal density should be considered when assessing TBE risks and designing interventions.
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Deviatkin AA, Karganova GG, Vakulenko YA, Lukashev AN. TBEV Subtyping in Terms of Genetic Distance. Viruses 2020; 12:E1240. [PMID: 33142676 PMCID: PMC7692686 DOI: 10.3390/v12111240] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 10/24/2020] [Accepted: 10/29/2020] [Indexed: 01/07/2023] Open
Abstract
Currently, the lowest formal taxon in virus classification is species; however, unofficial lower-level units are commonly used in everyday work. Tick-borne encephalitis virus (TBEV) is a species of mammalian tick-borne flaviviruses that may cause encephalitis. Many known representatives of TBEV are grouped into subtypes, mostly according to their phylogenetic relationship. However, the emergence of novel sequences could dissolve this phylogenetic grouping; in the absence of strict quantitative criterion, it may be hard to define the borders of the first TBEV taxonomic unit below the species level. In this study, the nucleotide/amino-acid space of all known TBEV sequences was analyzed. Amino-acid sequence p-distances could not reliably distinguish TBEV subtypes. Viruses that differed by less than 10% of nucleotides in the polyprotein-coding gene belonged to the same subtype. At the same time, more divergent viruses were representatives of different subtypes. According to this distance criterion, TBEV species may be divided into seven subtypes: TBEV-Eur, TBEV-Sib, TBEV-FE, TBEV-2871 (TBEV-Ob), TBEV-Him, TBEV-178-79 (TBEV-Bkl-1), and TBEV-886-84 (TBEV-Bkl-2).
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Affiliation(s)
- Andrei A. Deviatkin
- Laboratory of Molecular Biology and Biochemistry, Institute of Molecular Medicine, Sechenov First Moscow State Medical University, 119048 Moscow, Russia;
| | - Galina G. Karganova
- Department of Organization and Technology of Immunobiological Preparations, Institute for Translational Medicine and Biotechnology, Sechenov First Moscow State Medical University, 119991 Moscow, Russia;
- Laboratory of Biology of Arboviruses, Chumakov Institute of Poliomyelitis and Viral Encephalitides (FSBSI “Chumakov FSC R&D IBP RAS), 108819 Moscow, Russia
| | - Yulia A. Vakulenko
- Martsinovsky Institute of Medical Parasitology, Tropical and Vector Borne Diseases, Sechenov First Moscow State Medical University, 119435 Moscow, Russia;
- Department of Virology, Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Alexander N. Lukashev
- Laboratory of Molecular Biology and Biochemistry, Institute of Molecular Medicine, Sechenov First Moscow State Medical University, 119048 Moscow, Russia;
- Martsinovsky Institute of Medical Parasitology, Tropical and Vector Borne Diseases, Sechenov First Moscow State Medical University, 119435 Moscow, Russia;
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Deviatkin AA, Kholodilov IS, Belova OA, Bugmyrin SV, Bespyatova LA, Ivannikova AY, Vakulenko YA, Lukashev AN, Karganova GG. Baltic Group Tick-Borne Encephalitis Virus Phylogeography: Systemic Inconsistency Pattern between Genetic and Geographic Distances. Microorganisms 2020; 8:microorganisms8101589. [PMID: 33076346 PMCID: PMC7602664 DOI: 10.3390/microorganisms8101589] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 10/07/2020] [Accepted: 10/13/2020] [Indexed: 10/26/2022] Open
Abstract
Tick-Borne Encephalitis Virus (TBEV) is a dangerous arbovirus widely distributed in Northern Eurasia. The area of this pathogen changes over time. At the beginning of the 2000s, the Ixodes tick populations in Karelia increased. At the same time, the area of I. persulcatus, the main vector of the Siberian TBEV subtype, also expanded. Herein, we sequenced 10 viruses isolated from ticks collected in three locations from the Karelia region in 2008-2018. PCR positive samples were passaged in suckling mice or pig embryo kidney cells (PEK). After the second passage in suckling, mice viral RNA was isolated and E-gene fragment was sequenced. Viral sequences were expected to be similar or nearly identical. Instead, there was up to a 4.8% difference in nucleotide sequence, comparable with the most diverse viruses belonging to the Baltic subgroup in Siberian TBEV subtype (Baltic TBEV-Sib). To reveal whether this was systemic or incidental, a comprehensive phylogeographical analysis was conducted. Interestingly, viruses within each geographic region demonstrated comparable diversity to the whole Baltic TBEV-Sib. Moreover, Baltic TBEV-Sib has a distribution area limited by three ecological regions. This means that active virus mixing occurs in the vast geographic area forming one common virus pool. The most plausible explanation is the involvement of flying animals in the TBEV spread.
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Affiliation(s)
- Andrei A. Deviatkin
- Laboratory of Molecular Biology and Biochemistry, Institute of Molecular Medicine, Sechenov First Moscow State Medical University, 119048 Moscow, Russia;
- Correspondence: (A.A.D.); (G.G.K.)
| | - Ivan S. Kholodilov
- Laboratory of Biology of Arboviruses, Chumakov Institute of Poliomyelitis and Viral Encephalitides (FSBSI “Chumakov FSC R&D IBP RAS), 108819 Moscow, Russia; (I.S.K.); (O.A.B.); (A.Y.I.)
| | - Oxana A. Belova
- Laboratory of Biology of Arboviruses, Chumakov Institute of Poliomyelitis and Viral Encephalitides (FSBSI “Chumakov FSC R&D IBP RAS), 108819 Moscow, Russia; (I.S.K.); (O.A.B.); (A.Y.I.)
| | - Sergey V. Bugmyrin
- Laboratory for Animal and Plant Parasitology, Institute of Biology of the Karelian Research Centre of the Russian Academy of Sciences (IB KarRC RAS), 185910 Petrozavodsk, Russia; (S.V.B.); (L.A.B.)
| | - Lubov A. Bespyatova
- Laboratory for Animal and Plant Parasitology, Institute of Biology of the Karelian Research Centre of the Russian Academy of Sciences (IB KarRC RAS), 185910 Petrozavodsk, Russia; (S.V.B.); (L.A.B.)
| | - Anna Y. Ivannikova
- Laboratory of Biology of Arboviruses, Chumakov Institute of Poliomyelitis and Viral Encephalitides (FSBSI “Chumakov FSC R&D IBP RAS), 108819 Moscow, Russia; (I.S.K.); (O.A.B.); (A.Y.I.)
| | - Yulia A. Vakulenko
- Department of Virology, Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia;
- Martsinovsky Institute of Medical Parasitology, Tropical and Vector Borne Diseases, Sechenov First Moscow State Medical University, 119435 Moscow, Russia
| | - Alexander N. Lukashev
- Laboratory of Molecular Biology and Biochemistry, Institute of Molecular Medicine, Sechenov First Moscow State Medical University, 119048 Moscow, Russia;
- Martsinovsky Institute of Medical Parasitology, Tropical and Vector Borne Diseases, Sechenov First Moscow State Medical University, 119435 Moscow, Russia
| | - Galina G. Karganova
- Laboratory of Biology of Arboviruses, Chumakov Institute of Poliomyelitis and Viral Encephalitides (FSBSI “Chumakov FSC R&D IBP RAS), 108819 Moscow, Russia; (I.S.K.); (O.A.B.); (A.Y.I.)
- Department of Organization and Technology of Immunobiological Preparations, Institute for Translational Medicine and Biotechnology, Sechenov First Moscow State Medical University, 119991 Moscow, Russia
- Correspondence: (A.A.D.); (G.G.K.)
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Hahn MB, Disler G, Durden LA, Coburn S, Witmer F, George W, Beckmen K, Gerlach R. Establishing a baseline for tick surveillance in Alaska: Tick collection records from 1909-2019. Ticks Tick Borne Dis 2020; 11:101495. [PMID: 32723642 PMCID: PMC7447289 DOI: 10.1016/j.ttbdis.2020.101495] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 06/08/2020] [Accepted: 06/10/2020] [Indexed: 10/24/2022]
Abstract
The expanding geographic ranges of tick species that are known pathogen vectors can have implications for human, domestic animal, and wildlife health. Although Alaska is home to several hard tick species, it has historically been outside of the range of the most common medically important ticks in the contiguous United States and western Canada. To assess the status of tick species establishment in the state and to provide a baseline for tracking future change in the distribution of ticks, we reviewed and compiled historical tick records and summarized recent tick occurrence records collected through the development of the Alaska Submit-A-Tick Program and through tick drag sampling at sentinel sites in southcentral Alaska. Between 1909-2019, there were 1190 tick records representing 4588 individual ticks across 15 species in Alaska. The majority of ticks were species historically found in Alaska: Haemaphysalis leporispalustris, Ixodes angustus, Ixodes auritulus, Ixodes howelli, Ixodes signatus, and Ixodes uriae. Over half of all tick records in the state were collected in the last 10 yr. During this time, the number of tick records and the number of tick species recorded in Alaska each year has increased substantially. Between 2010-2019, there were 611 tick records representing 1921 individual ticks. The most common hosts for reported ticks were domestic animals (n = 343, 56 %) followed by small wild mammals (n = 147, 24 %), humans (n = 49, 8%), and wild birds (n = 31, 5%). Less than 5% of records (n = 25) were of unattached ticks found in the environment. Since 2007, non-native tick species have been documented in the state every year, including Amblyomma americanum, Dermacentor andersoni, Dermacentor occidentalis, Dermacentor variabilis, Ixodes pacificus, Ixodes ricinus, Ixodes scapularis, Ixodes texanus, and Rhipicephalus sanguineus sensu lato (s.l.). Almost half of the records (n = 68, 48 %) of non-native tick species from 2010 to 2019 represented ticks found on a host (usually a dog or a human) that had traveled outside of Alaska in the two weeks prior to collection. However, A. americanum, D. variabilis, I. pacificus, I. texanus, and R. sanguineus s.l. have been found on humans and domestic animals in Alaska without reported recent travel. In particular, there is evidence to suggest that there is local establishment of R. sanguineus s.l. in Alaska. A tick species historically found in the state, I. angustus was frequently found on human and dogs, suggesting a potential role as a bridge vector of pathogens. Given the inconsistency of tick monitoring in Alaska over the past century, it is difficult to draw many conclusions from temporal trends in the data. Continued monitoring through the Alaska Submit-A-Tick Program will allow a more accurate assessment of the changing risk of ticks and tick-borne diseases in the state and provide information for setting clinical and public health guidelines for tick-borne disease prevention.
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Affiliation(s)
- Micah B Hahn
- Institute for Circumpolar Health, University of Alaska-Anchorage, 3211 Providence Drive, BOC3 270, Anchorage, Alaska 99508, United States.
| | - Gale Disler
- Division of Population Health Sciences, University of Alaska-Anchorage, United States.
| | - Lance A Durden
- Department of Biology, Georgia Southern University, 4324 Old Register Road, Statesboro, GA 30458, United States.
| | - Sarah Coburn
- Alaska Department of Environmental Conservation, Office of the State Veterinarian, 5251 Dr. Martin Luther King Jr. Ave, Anchorage, AK 99507, United States.
| | - Frank Witmer
- Department of Computer Science and Engineering, University of Alaska-Anchorage, United States.
| | - William George
- Department of Biological Sciences, University of Alaska-Anchorage, United States.
| | - Kimberlee Beckmen
- Alaska Department of Fish and Game, Division of Wildlife Conservation, Wildlife Health and Disease, Surveillance Program, 1300 College Road, Fairbanks, Alaska 99701, United States.
| | - Robert Gerlach
- Alaska Department of Environmental Conservation, Office of the State Veterinarian, 5251 Dr. Martin Luther King Jr. Ave, Anchorage, AK 99507, United States.
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10
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Uusitalo R, Siljander M, Dub T, Sane J, Sormunen JJ, Pellikka P, Vapalahti O. Modelling habitat suitability for occurrence of human tick-borne encephalitis (TBE) cases in Finland. Ticks Tick Borne Dis 2020; 11:101457. [PMID: 32723626 DOI: 10.1016/j.ttbdis.2020.101457] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 04/22/2020] [Accepted: 04/24/2020] [Indexed: 12/11/2022]
Abstract
The numbers of reported human tick-borne encephalitis (TBE) cases in Europe have increased in several endemic regions (including Finland) in recent decades, indicative of an increasing threat to public health. As such, it is important to identify the regions at risk and the most influential factors associated with TBE distributions, particularly in understudied regions. This study aimed to identify the risk areas of TBE transmission in two different datasets based on human TBE disease cases from 2007 to 2011 (n = 86) and 2012-2017 (n = 244). We also examined which factors best explain the presence of human TBE cases. We used ensemble modelling to determine the relationship of TBE occurrence with environmental, ecological, and anthropogenic factors in Finland. Geospatial data including these variables were acquired from several open data sources and satellite and aerial imagery and, were processed in GIS software. Biomod2, an ensemble platform designed for species distribution modelling, was used to generate ensemble models in R. The proportion of built-up areas, field, forest, and snow-covered land in November, people working in the primary sector, human population density, mean precipitation in April and July, and densities of European hares, white-tailed deer, and raccoon dogs best estimated distribution of human TBE disease cases in the two datasets. Random forest and generalized boosted regression models performed with a very good to excellent predictive power (ROC = 0.89-0.96) in both time periods. Based on the predictive maps, high-risk areas for TBE transmission were located in the coastal regions in Southern and Western Finland (including the Åland Islands), several municipalities in Central and Eastern Finland, and coastal municipalities in Southern Lapland. To explore potential changes in TBE distributions in future climate, we used bioclimatic factors with current and future climate forecast data to reveal possible future hotspot areas. Based on the future forecasts, a slightly wider geographical extent of TBE risk was introduced in the Åland Islands and Southern, Western and Northern Finland, even though the risk itself was not increased. Our results are the first steps towards TBE-risk area mapping in current and future climate in Finland.
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Affiliation(s)
- Ruut Uusitalo
- Department of Geosciences and Geography, P.O. Box 64, FI-00014, University of Helsinki, Finland; Department of Virology, Haartmaninkatu 3, P.O. Box 21, FI-00014, University of Helsinki, Finland; Department of Veterinary Biosciences, Agnes Sjöberginkatu 2, P.O. Box 66, FI-00014, University of Helsinki, Finland.
| | - Mika Siljander
- Department of Geosciences and Geography, P.O. Box 64, FI-00014, University of Helsinki, Finland.
| | - Timothée Dub
- National Institute for Health and Welfare, Helsinki, Finland; European Programme for Intervention Epidemiology Training (EPIET), European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden.
| | - Jussi Sane
- National Institute for Health and Welfare, Helsinki, Finland.
| | | | - Petri Pellikka
- Department of Geosciences and Geography, P.O. Box 64, FI-00014, University of Helsinki, Finland; Helsinki Institute of Sustainability Science, University of Helsinki, Finland; Institute for Atmospheric and Earth System Research, University of Helsinki, Finland.
| | - Olli Vapalahti
- Department of Virology, Haartmaninkatu 3, P.O. Box 21, FI-00014, University of Helsinki, Finland; Department of Veterinary Biosciences, Agnes Sjöberginkatu 2, P.O. Box 66, FI-00014, University of Helsinki, Finland; Virology and Immunology, HUSLAB, Helsinki University Hospital, Finland.
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11
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Deviatkin AA, Kholodilov IS, Vakulenko YA, Karganova GG, Lukashev AN. Tick-Borne Encephalitis Virus: An Emerging Ancient Zoonosis? Viruses 2020; 12:v12020247. [PMID: 32102228 PMCID: PMC7077300 DOI: 10.3390/v12020247] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 02/10/2020] [Accepted: 02/19/2020] [Indexed: 12/19/2022] Open
Abstract
Tick-borne encephalitis (TBE) is one of the most important viral zoonosis transmitted by the bite of infected ticks. In this study, all tick-borne encephalitis virus (TBEV) E gene sequences available in GenBank as of June 2019 with known date of isolation (n = 551) were analyzed. Simulation studies showed that a sample bias could significantly affect earlier studies, because small TBEV datasets (n = 50) produced non-overlapping intervals for evolutionary rate estimates. An apparent lack of a temporal signal in TBEV, in general, was found, precluding molecular clock analysis of all TBEV subtypes in one dataset. Within all subtypes and most of the smaller groups in these subtypes, there was evidence of many medium- and long-distance virus transfers. These multiple random events may play a key role in the virus spreading. For some groups, virus diversity within one territory was similar to diversity over the whole geographic range. This is best exemplified by the virus diversity observed in Switzerland or Czech Republic. These two countries yielded most of the known European subtype Eu3 subgroup sequences, and the diversity of viruses found within each of these small countries is comparable to that of the whole Eu3 subgroup, which is prevalent all over Central and Eastern Europe. Most of the deep tree nodes within all three established TBEV subtypes dated less than 300 years back. This could be explained by the recent emergence of most of the known TBEV diversity. Results of bioinformatics analysis presented here, together with multiple field findings, suggest that TBEV may be regarded as an emerging disease.
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Affiliation(s)
- Andrei A. Deviatkin
- Laboratory of Molecular Biology and Biochemistry, Institute of Molecular Medicine, Sechenov First Moscow State Medical University, 119048 Moscow, Russia;
- Laboratory of Postgenomic Technologies, Izmerov Research Institute of Occupational Health, 105275 Moscow, Russia
- Correspondence: ; Tel.: +7-906-739-0860
| | - Ivan S. Kholodilov
- Laboratory of Biology of Arboviruses, Chumakov Institute of Poliomyelitis and Viral Encephalitides (FSBSI “Chumakov FSC R&D IBP RAS), 108819 Moscow, Russia; (I.S.K.); (G.G.K.)
| | - Yulia A. Vakulenko
- Martsinovsky Institute of Medical Parasitology, Tropical and Vector Borne Diseases, Sechenov First Moscow State Medical University, 119435 Moscow, Russia;
- Department of Virology, Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Galina G. Karganova
- Laboratory of Biology of Arboviruses, Chumakov Institute of Poliomyelitis and Viral Encephalitides (FSBSI “Chumakov FSC R&D IBP RAS), 108819 Moscow, Russia; (I.S.K.); (G.G.K.)
- Department of Organization and Technology of Immunobiological Preparations, Institute for Translational Medicine and Biotechnology, Sechenov First Moscow State Medical University, 119991 Moscow, Russia
| | - Alexander N. Lukashev
- Laboratory of Molecular Biology and Biochemistry, Institute of Molecular Medicine, Sechenov First Moscow State Medical University, 119048 Moscow, Russia;
- Martsinovsky Institute of Medical Parasitology, Tropical and Vector Borne Diseases, Sechenov First Moscow State Medical University, 119435 Moscow, Russia;
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12
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Viral Equine Encephalitis, a Growing Threat to the Horse Population in Europe? Viruses 2019; 12:v12010023. [PMID: 31878129 PMCID: PMC7019608 DOI: 10.3390/v12010023] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 12/15/2019] [Accepted: 12/17/2019] [Indexed: 12/20/2022] Open
Abstract
Neurological disorders represent an important sanitary and economic threat for the equine industry worldwide. Among nervous diseases, viral encephalitis is of growing concern, due to the emergence of arboviruses and to the high contagiosity of herpesvirus-infected horses. The nature, severity and duration of the clinical signs could be different depending on the etiological agent and its virulence. However, definite diagnosis generally requires the implementation of combinations of direct and/or indirect screening assays in specialized laboratories. The equine practitioner, involved in a mission of prevention and surveillance, plays an important role in the clinical diagnosis of viral encephalitis. The general management of the horse is essentially supportive, focused on controlling pain and inflammation within the central nervous system, preventing injuries and providing supportive care. Despite its high medical relevance and economic impact in the equine industry, vaccines are not always available and there is no specific antiviral therapy. In this review, the major virological, clinical and epidemiological features of the main neuropathogenic viruses inducing encephalitis in equids in Europe, including rabies virus (Rhabdoviridae), Equid herpesviruses (Herpesviridae), Borna disease virus (Bornaviridae) and West Nile virus (Flaviviridae), as well as exotic viruses, will be presented.
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13
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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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14
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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:v11070669. [PMID: 31336624 PMCID: PMC6669706 DOI: 10.3390/v11070669] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [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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15
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Kjær LJ, Soleng A, Edgar KS, Lindstedt HEH, Paulsen KM, Andreassen ÅK, Korslund L, Kjelland V, Slettan A, Stuen S, Kjellander P, Christensson M, Teräväinen M, Baum A, Isbrand A, Jensen LM, Klitgaard K, Bødker R. A large-scale screening for the taiga tick, Ixodes persulcatus, and the meadow tick, Dermacentor reticulatus, in southern Scandinavia, 2016. Parasit Vectors 2019; 12:338. [PMID: 31288866 PMCID: PMC6617640 DOI: 10.1186/s13071-019-3596-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 07/03/2019] [Indexed: 12/30/2022] Open
Abstract
The taiga tick, Ixodes persulcatus, has previously been limited to eastern Europe and northern Asia, but recently its range has expanded to Finland and northern Sweden. The species is of medical importance, as it, along with a string of other pathogens, may carry the Siberian and Far Eastern subtypes of tick-borne encephalitis virus. These subtypes appear to cause more severe disease, with higher fatality rates than the central European subtype. Until recently, the meadow tick, Dermacentor reticulatus, has been absent from Scandinavia, but has now been detected in Denmark, Norway and Sweden. Dermacentor reticulatus carries, along with other pathogens, Babesia canis and Rickettsia raoultii. Babesia canis causes severe and often fatal canine babesiosis, and R. raoultii may cause disease in humans. We collected 600 tick nymphs from each of 50 randomly selected sites in Denmark, southern Norway and south-eastern Sweden in August–September 2016. We tested pools of 10 nymphs in a Fluidigm real time PCR chip to screen for I. persulcatus and D. reticulatus, as well as tick-borne pathogens. Of all the 30,000 nymphs tested, none were I. persulcatus or D. reticulatus. Our results suggest that I. persulcatus is still limited to the northern parts of Sweden, and have not expanded into southern parts of Scandinavia. According to literature reports and supported by our screening results, D. reticulatus may yet only be an occasional guest in Scandinavia without established populations.
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Affiliation(s)
- Lene Jung Kjær
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark.
| | - Arnulf Soleng
- Department of Pest Control, Norwegian Institute of Public Health, Oslo, Norway
| | | | | | - Katrine Mørk Paulsen
- Department of Virology, Norwegian Institute of Public Health, Oslo, Norway.,Department of Production Animal Clinical Sciences, Norwegian University of Life Sciences, Oslo, Norway
| | | | - Lars Korslund
- Department of Natural Sciences, University of Agder, Kristiansand, Norway
| | - Vivian Kjelland
- Department of Natural Sciences, University of Agder, Kristiansand, Norway.,Sørlandet Hospital Health Enterprise, Research Unit, Kristiansand, Norway
| | - Audun Slettan
- Department of Natural Sciences, University of Agder, Kristiansand, Norway
| | - Snorre Stuen
- Department of Production Animal Clinical Sciences, Section of Small Ruminant Research, Norwegian University of Life Sciences, Sandnes, Norway
| | - Petter Kjellander
- Wildlife Ecology Unit, Department of Ecology, Swedish University of Agricultural Sciences, Grimsö, Sweden
| | - Madeleine Christensson
- Wildlife Ecology Unit, Department of Ecology, Swedish University of Agricultural Sciences, Grimsö, Sweden
| | - Malin Teräväinen
- Wildlife Ecology Unit, Department of Ecology, Swedish University of Agricultural Sciences, Grimsö, Sweden
| | - Andreas Baum
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, Lyngby, Denmark
| | - Anastasia Isbrand
- Department for Diagnostics and Scientific Advice, National Veterinary Institute, Technical University of Denmark, Lyngby, Denmark
| | - Laura Mark Jensen
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Kirstine Klitgaard
- Department for Diagnostics and Scientific Advice, National Veterinary Institute, Technical University of Denmark, Lyngby, Denmark
| | - René Bødker
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
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16
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Klemola T, Sormunen JJ, Mojzer J, Mäkelä S, Vesterinen EJ. High tick abundance and diversity of tick-borne pathogens in a Finnish city. Urban Ecosyst 2019. [DOI: 10.1007/s11252-019-00854-w] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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17
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Comparative Analysis of NS5 Protein for Tick Borne Encephalitis Virus Strains in three Virus Subtypes. ACTA BIOMEDICA SCIENTIFICA 2019. [DOI: 10.29413/abs.2018-3.6.5] [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
Non-structural protein 5 (NS5) of tick-borne encephalitis virus is an enzyme which is responsible for a copying of viral RNA, and it has a strong structural similarity to RNA polymerases of another RNA virus families. The strains of the virus are separated into three subtypes, which differ by specific mutations in virus proteins, including NS5 protein. The methods of structural bioinformatics allow to construct a model of NS5 protein for several strains of the virus.The paper presents the comparative analysis of sequences and structures of NS5 protein, for three subtypes of the tick-borne encephalitis virus. The segments of protein were identified where the highest difference between subtypes and within subtypes is observed. These segments, where most of the mutations are accumulated, are located in methyltransferase domain, in the inter-domain interface, and in the three subdomains of polymerase domain. The association between the locations of mutations in NS5 protein and the flexibility of a protein backbone was observed using normal mode analysis. Namely, the most important mutations are located in the parts of protein where the amplitude of synchronous oscillations estimated using normal mode analysis is the highest: in the second zinc binding pocket within polymerase domain, in the N-terminal extension within inter-domain interface, and around an active site of methyltransferase domain.
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18
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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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Sormunen JJ, Klemola T, Hänninen J, Mäkelä S, Vuorinen I, Penttinen R, Sääksjärvi IE, Vesterinen EJ. The importance of study duration and spatial scale in pathogen detection-evidence from a tick-infested island. Emerg Microbes Infect 2018; 7:189. [PMID: 30482899 PMCID: PMC6258729 DOI: 10.1038/s41426-018-0188-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 09/24/2018] [Accepted: 10/21/2018] [Indexed: 12/11/2022]
Abstract
Ticks (Acari: Ixodoidea) are among the most common vectors of zoonotic pathogens worldwide. While research on tick-borne pathogens is abundant, few studies have thoroughly investigated small-scale spatial differences in their occurrence. Here, we used long-term cloth-dragging data of Ixodes ricinus and its associated, known and putative pathogens (Borrelia burgdorferi s.l., Borrelia miyamotoi, Anaplasma phagocytophilum, Rickettsia spp., Candidatus Neoehrlichia mikurensis, Bartonella spp., Babesia spp., and tick-borne encephalitis virus, TBEV) from a small, well-studied island in southwestern Finland to analyze potential temporal and spatial differences in pathogen prevalence and diversity between and within different biotopes. We found robust evidence indicating significant dissimilarities in B. burgdorferi s.l., A. phagocytophilum, Rickettsia, and Ca. N. mikurensis prevalence, even between proximal study areas on the island. Moreover, during the 6 years of the ongoing study, we witnessed the possible emergence of TBEV and Ca. N. mikurensis on the island. Finally, the stable occurrence of a protozoan pathogen that has not been previously reported in Finland, Babesia venatorum, was observed on the island. Our study underlines the importance of detailed, long-term tick surveys for public health. We propose that by more precisely identifying different environmental factors associated with the emergence and upkeep of enzootic pathogen populations through rigorous longitudinal surveys, we may be able to create more accurate models for both current and future pathogen distributions.
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Affiliation(s)
- Jani Jukka Sormunen
- Department of Biology, University of Turku, FI-20014, Turku, Finland. .,Biodiversity Unit, University of Turku, FI-20014, Turku, Finland.
| | - Tero Klemola
- Department of Biology, University of Turku, FI-20014, Turku, Finland
| | - Jari Hänninen
- Biodiversity Unit, University of Turku, FI-20014, Turku, Finland
| | - Satu Mäkelä
- Department of Biology, University of Turku, FI-20014, Turku, Finland
| | - Ilppo Vuorinen
- Biodiversity Unit, University of Turku, FI-20014, Turku, Finland
| | - Ritva Penttinen
- Biodiversity Unit, University of Turku, FI-20014, Turku, Finland
| | | | - Eero Juhani Vesterinen
- Biodiversity Unit, University of Turku, FI-20014, Turku, Finland.,Deparment of Agricultural Sciences, University of Helsinki, FI-00014, Helsinki, Finland
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20
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Abstract
Since 2012, tick-borne encephalitis (TBE) is a notifiable in the European Union. The European Centre for Disease Prevention and Control annually collects data from 28 countries plus Iceland and Norway, based on the EU case definition. Between 2012 and 2016, 23 countries reported 12,500 TBE cases (Ireland and Spain reported none), of which 11,623 (93.0%) were confirmed cases and 878 (7.0%) probable cases. Two countries (Czech Republic and Lithuania) accounted for 38.6% of all reported cases, although their combined population represented only 2.7% of the population under surveillance. The annual notification rate fluctuated between 0.41 cases per 100,000 population in 2015 and 0.65 in 2013 with no significant trend over the period. Lithuania, Latvia and Estonia had the highest notification rates with 15.6, 9.5 and 8.7 cases per 100,000 population, respectively. At the subnational level, six regions had mean annual notification rates above 15 cases per 100,000 population, of which five were in the Baltic countries. Approximately 95% of cases were hospitalised and the overall case fatality ratio was 0.5%. Of the 11,663 cases reported with information on importation status, 156 (1.3%) were reported as imported. Less than 2% of cases had received two or more doses of TBE vaccine.
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Affiliation(s)
- Julien Beauté
- European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden
| | - Gianfranco Spiteri
- European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden
| | - Eva Warns-Petit
- European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden (affiliation when the work was performed),Direction Départementale de la Cohésion Sociale et de la Protection des Populations d’Ille-et-Vilaine, Rennes, France (current affiliation)
| | - Hervé Zeller
- European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden (affiliation when the work was performed)
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21
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Panferova YA, Suvorova MA, Shapar AO, Tokarevich NK. BACTERIAL AND VIRAL PATHOGENS IN IXODES SP. TICKS IN ST. PETERSBURG AND LENINGRAD DISTRICT. RUSSIAN JOURNAL OF INFECTION AND IMMUNITY 2018. [DOI: 10.15789/2220-7619-2018-2-219-222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Tick-borne infections are the most common group of zooanthroponotic diseases in the Northern Hemisphere. For the Baltic Sea region and Fennoscandia, the dominant infectious pathologies transmitted by ticks are tick-borne borreliosis and tick- borne encephalitis. The presence of vast forested areas, actively visited by people in St. Petersburg and the Leningrad region, contributes to a rather high level of encroachment on the flares and intelligence of the borreliosis and tick-borne encephalitis among the population of these regions. The relatively dangerous pathogens that can be transmitted with the tick bite are also of particular danger: Anaplasma sp., Ehrlichia sp., Coxiella burnetii, Rickettsia sp. In this work, detection was performed using molecular genetic methods of TBE virus, B. burgdorferi sensu lato and Rickettsia sp. in engorged ticksple, as well as questing ticks collected from vegetation. The established levels of infection of TBE on infected ticks, levels of infection by pathogenic Borrelia of questing and engorgeded ticks were approximately equal. Rickettsia was not found in the ticks. The conducted analysis of the pathogens prevalence in comparison with the data of russian and foreign authors. Monitoring the prevalence of tick-borne pathogens is an important issue in the prevention of tick- borne infections in the North-Western Russia.
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NECESSITY TO IMPROVE THE EMERGENCY DIAGNOSTICS OF TICK-BORNE INFECTIONS IN PEOPLE BITTEN BY IXODID TICKS ABROAD OF THE RUSSIAN FEDERATION. ACTA BIOMEDICA SCIENTIFICA 2018. [DOI: 10.29413/abs.2018-3.4.19] [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
Introduction. Annually, there are several patients attended the Center for Diagnosis and Prevention of Tick-borne Infections in Irkutsk after bites of ticks that happened outside the Pribaikalye region or abroad. In such cases, the attacking ticks do not belong to convenient species that are usual for Eastern Siberia. Consequently, the spectrum of pathogenic microorganisms transmitted by these ticks may significantly differ from those that are detected by usual laboratory tests. Thus, both physicians and laboratory personnel may have difficulties in proper detection and identification of pathogens as well as in diagnosing and treating of such patients.The purpose of the study was the analysis of potential risks of human infection with the pathogens that are common in foreign countries outside the Russian Federation.Material and methods. The article uses information from electronic databases created by the authors during 2007-2017.Results and discussion. During 11 years of observations, 52 tick bites were registered in 20 countries, with 48 of them in the Eastern Hemisphere (92.3 %), three (5.8 %) in the United States and one (1.9 %) in the Republic of Cuba. The results indicate a real danger of infection by tick-borne pathogens of people traveling as the tourists and with business purposes to the countries of Europe, Asia and America. Conclusion. It is necessary to improve the existing algorithm for diagnosis, prevention and treatment for people bitten by ixodid ticks outside the Russian Federation, taking into account the possibility of infection by inconvenient imported infections.
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Crowdsourcing-based nationwide tick collection reveals the distribution of Ixodes ricinus and I. persulcatus and associated pathogens in Finland. Emerg Microbes Infect 2017; 6:e31. [PMID: 28487561 PMCID: PMC5584484 DOI: 10.1038/emi.2017.17] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 01/27/2017] [Accepted: 02/06/2017] [Indexed: 11/08/2022]
Abstract
A national crowdsourcing-based tick collection campaign was organized in 2015 with the objective of producing novel data on tick distribution and tick-borne pathogens in Finland. Nearly 20 000 Ixodes ticks were collected. The collected material revealed the nationwide distribution of I. persulcatus for the first time and a shift northwards in the distribution of I. ricinus in Finland. A subset of 2038 tick samples containing both species was screened for Borrelia burgdorferi sensu lato (the prevalence was 14.2% for I. ricinus and 19.8% for I. persulcatus), B. miyamotoi (0.2% and 0.4%, respectively) and tick-borne encephalitis virus (TBEV; 0.2% and 3.0%, respectively). We also report new risk areas for TBEV in Finland and, for the first time, the presence of B. miyamotoi in ticks from mainland Finland. Most importantly, our study demonstrates the overwhelming power of citizen science in accomplishing a collection effort that would have been impossible with the scientific community alone.
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Ixodes persulcatus Ticks as Vectors for the Babesia microti U.S. Lineage in Japan. Appl Environ Microbiol 2016; 82:6624-6632. [PMID: 27590815 DOI: 10.1128/aem.02373-16] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 08/26/2016] [Indexed: 12/19/2022] Open
Abstract
The U.S. lineage, one of the major clades in the Babesia microti group, is known as a causal agent of human babesiosis mostly in the northeastern and upper midwestern United States. This lineage, however, also is distributed throughout the temperate zone of Eurasia with several reported human cases, although convincing evidence of the identity of the specific vector(s) in this area is lacking. Here, the goal was to demonstrate the presence of infectious parasites directly in salivary glands of Ixodes persulcatus, from which U.S. lineage genetic sequences have been detected in Asia, and to molecularly characterize the isolates. Five PCR-positive specimens were individually inoculated into hamsters, resulting in infections in four; consequently, four strains were newly established. Molecular characterization, including 18S rRNA, β-tubulin, and CCT7 gene sequences, as well as Western blot analysis and indirect fluorescent antibody assay, revealed that all four strains were identical to each other and to the U.S. lineage strains isolated from rodents captured in Japan. The 18S rRNA gene sequence from the isolates was identical to those from I. persulcatus in Russia and China, but the genetic and antigenic profiles of the Japanese parasites differ from those in the United States and Europe. Together with previous epidemiological and transmission studies, we conclude that I. persulcatus is likely the principal vector for the B. microti U.S. lineage in Japan and presumably in northeastern Eurasia. IMPORTANCE The major cause of human babesiosis, the tick-borne blood parasite Babesia microti, U.S. lineage, is widely distributed in the temperate Northern Hemisphere. However, the specific tick vector(s) remains unidentified in Eurasia, where there are people with antibodies to the B. microti U.S. lineage and cases of human babesiosis. In this study, the first isolation of B. microti U.S. lineage from Ixodes persulcatus ticks, a principal vector for many tick-borne diseases, is described in Japan. Limited antigenic cross-reaction was found between the Japan and United States isolates. Thus, current serological tests based on U.S. isolates may underestimate B. microti occurrence outside the United States. This study and previous studies indicate that I. persulcatus is part of the B. microti U.S. lineage life cycle in Japan and, presumably, northeastern Eurasia. This report will be important for public health, especially since infection may occur through transfusion, and also to researchers in the field of parasitology.
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Jaenson TGT, Värv K, Fröjdman I, Jääskeläinen A, Rundgren K, Versteirt V, Estrada-Peña A, Medlock JM, Golovljova I. First evidence of established populations of the taiga tick Ixodes persulcatus (Acari: Ixodidae) in Sweden. Parasit Vectors 2016; 9:377. [PMID: 27370406 PMCID: PMC5116163 DOI: 10.1186/s13071-016-1658-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 06/20/2016] [Indexed: 12/30/2022] Open
Abstract
Background The tick species Ixodes ricinus and I. persulcatus are of exceptional medical importance in the western and eastern parts, respectively, of the Palaearctic region. In Russia and Finland the range of I. persulcatus has recently increased. In Finland the first records of I. persulcatus are from 2004. The apparent expansion of its range in Finland prompted us to investigate if I. persulcatus also occurs in Sweden. Methods Dog owners and hunters in the coastal areas of northern Sweden provided information about localities where ticks could be present. In May-August 2015 we used the cloth-dragging method in 36 localities potentially harbouring ticks in the Bothnian Bay area, province Norrbotten (NB) of northern Sweden. Further to the south in the provinces Västerbotten (VB) and Uppland (UP) eight localities were similarly investigated. Results Ixodes persulcatus was detected in 9 of 36 field localities in the Bothnian Bay area. Nymphs, adult males and adult females (n = 46 ticks) of I. persulcatus were present mainly in Alnus incana - Sorbus aucuparia - Picea abies - Pinus sylvestris vegetation communities on islands in the Bothnian Bay. Some of these I. persulcatus populations seem to be the most northerly populations so far recorded of this species. Dog owners asserted that their dogs became tick-infested on these islands for the first time 7–8 years ago. Moose (Alces alces), hares (Lepus timidus), domestic dogs (Canis lupus familiaris) and ground-feeding birds are the most likely carriers dispersing I. persulcatus in this area. All ticks (n = 124) from the more southern provinces of VB and UP were identified as I. ricinus. Conclusions The geographical range of the taiga tick has recently expanded into northern Sweden. Increased information about prophylactic, anti-tick measures should be directed to people living in or visiting the coastal areas and islands of the Baltic Bay. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1658-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Thomas G T Jaenson
- Medical Entomology Unit, Department of Organismal Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18d, SE-752 36, Uppsala, Sweden.
| | - Kairi Värv
- Department of Virology, National Institute for Health Development, Hiiu 42, 11619, Tallinn, Estonia
| | | | - Anu Jääskeläinen
- Department of Virology, University of Helsinki, P.O. Box 21, FI-00014, Helsinki, Finland
| | | | - Veerle Versteirt
- Precision Pest Management Unit, Avia-GIS, Risschotlei 33, BE-2980, Zoersel, Belgium
| | - Agustín Estrada-Peña
- Department of Parasitology, University of Zaragoza, Miguel Servet 177, ES-50013, Zaragoza, Spain
| | - Jolyon M Medlock
- Medical Entomology Group, Emergency Response Department, Public Health England, Porton Down, Salisbury, UK.,Health Protection Research Unit in Emerging Infections and Zoonoses, Porton Down, Salisbury, UK
| | - Irina Golovljova
- Department of Virology, National Institute for Health Development, Hiiu 42, 11619, Tallinn, Estonia
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26
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Levanov L, Vera CP, Vapalahti O. Prevalence estimation of tick-borne encephalitis virus (TBEV) antibodies in dogs from Finland using novel dog anti-TBEV IgG MAb-capture and IgG immunofluorescence assays based on recombinant TBEV subviral particles. Ticks Tick Borne Dis 2016; 7:979-982. [PMID: 27189583 DOI: 10.1016/j.ttbdis.2016.05.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 04/24/2016] [Accepted: 05/04/2016] [Indexed: 11/17/2022]
Abstract
Tick-borne encephalitis (TBE) is one of the most dangerous human neurological infections occurring in Europe and Northern parts of Asia with thousands of cases and millions vaccinated against it. The risk of TBE might be assessed through analyses of the samples taken from wildlife or from animals which are in close contact with humans. Dogs have been shown to be a good sentinel species for these studies. Serological assays for diagnosis of TBE in dogs are mainly based on purified and inactivated TBEV antigens. Here we describe novel dog anti-TBEV IgG monoclonal antibody (MAb)-capture assay which is based on TBEV prME subviral particles expressed in mammalian cells from Semliki Forest virus (SFV) replicon as well as IgG immunofluorescence assay (IFA) which is based on Vero E6 cells transfected with the same SFV replicon. We further demonstrate their use in a small-scale TBEV seroprevalence study of dogs representing different regions of Finland. Altogether, 148 dog serum samples were tested by novel assays and results were compared to those obtained with a commercial IgG enzyme immunoassay (EIA), hemagglutination inhibition test and IgG IFA with TBEV infected cells. Compared to reference tests, the sensitivities of the developed assays were 90-100% and the specificities of the two assays were 100%. Analysis of the dog serum samples showed a seroprevalence of 40% on Åland Islands and 6% on Southwestern archipelago of Finland. In conclusion, a specific and sensitive EIA and IFA for the detection of IgG antibodies in canine sera were developed. Based on these assays the seroprevalence of IgG antibodies in dogs from different regions of Finland was assessed and was shown to parallel the known human disease burden as the Southwestern archipelago and Åland Islands in particular had considerable dog TBEV antibody prevalence and represent areas with high risk of TBE for humans.
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Affiliation(s)
- Lev Levanov
- Department of Virology, University of Helsinki, Helsinki, Finland.
| | - Cristina Pérez Vera
- Department of Virology, University of Helsinki, Helsinki, Finland; Department of Equine and Small Animal Medicine, University of Helsinki, Helsinki, Finland; Department of Clinical Veterinary Studies, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
| | - Olli Vapalahti
- Department of Virology, University of Helsinki, Helsinki, Finland; Department of Virology and Immunology, Helsinki University Hospital, Helsinki, Finland; Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland.
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Tonteri E, Kurkela S, Timonen S, Manni T, Vuorinen T, Kuusi M, Vapalahti O. Surveillance of endemic foci of tick-borne encephalitis in Finland 1995-2013: evidence of emergence of new foci. ACTA ACUST UNITED AC 2016; 20:30020. [PMID: 26535471 DOI: 10.2807/1560-7917.es.2015.20.37.30020] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 04/23/2015] [Indexed: 12/30/2022]
Abstract
The geographical risk areas for tick-borne encephalitis (TBE) in Finland remained the same until the beginning of the 21st century, but a considerable geographical expansion has been observed in the past 10 years. In order to support public health measures, the present study describes the number of laboratory-confirmed TBE cases and laboratory tests conducted and the associated trends by hospital district, with a particular emphasis on the suspected geographical risk areas. An additional investigation was conducted on 1,957 clinical serum samples throughout the country taken from patients with neurological symptoms to screen for undiagnosed TBE cases. This study identified new TBE foci in Finland, reflecting the spread of the disease into new areas. Even in the most endemic municipalities, transmission of TBE to humans occurred in very specific and often small foci. The number of antibody tests for TBE virus more than doubled (an increase by 105%) between 2007 and 2013. Analysis of the number of tests also revealed areas in which the awareness of clinicians may be suboptimal at present. However, it appears that underdiagnosis of neuroinvasive TBE is not common.
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Affiliation(s)
- Elina Tonteri
- Departments of Virology and Veterinary Biosciences, University of Helsinki, Helsinki, Finland
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28
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Levanov L, Jääskeläinen A, Vapalahti O. Test based on subtype-specific μ-capture IgM immunoassay can distinguish between infections of European and Siberian subtypes of tick-borne encephalitis virus. J Clin Virol 2015; 73:81-83. [DOI: 10.1016/j.jcv.2015.11.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 10/29/2015] [Accepted: 11/01/2015] [Indexed: 10/22/2022]
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Assessing the abundance, seasonal questing activity, and Borrelia and tick-borne encephalitis virus (TBEV) prevalence of Ixodes ricinus ticks in a Lyme borreliosis endemic area in Southwest Finland. Ticks Tick Borne Dis 2015; 7:208-215. [PMID: 26548608 DOI: 10.1016/j.ttbdis.2015.10.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 09/14/2015] [Accepted: 10/15/2015] [Indexed: 12/27/2022]
Abstract
Studies have revealed that Ixodes ricinus (Acari: Ixodidae) have become more abundant and their geographical distribution extended northwards in some Nordic countries during the past few decades. However, ecological data of tick populations in Finland are sparse. In the current study, I. ricinus abundance, seasonal questing activity, and their Borrelia spp. and tick-borne encephalitis virus (TBEV) prevalence were evaluated in a Lyme borreliosis endemic area in Southwest Finland, Seili Island, where a previous study mapping tick densities was conducted 12 years earlier. A total of 1940 ticks were collected from five different biotopes by cloth dragging during May-September 2012. The overall tick density observed was 5.2 ticks/100m(2) for nymphs and adults. Seasonal questing activity of ticks differed between biotopes and life stages: bimodal occurrences were observed especially for nymphal and adult ticks in forested biotopes, while larvae in pastures exhibited mostly unimodal occurrence. Prevalence of Borrelia and TBEV in ticks was evaluated using conventional and real-time PCR. All samples were negative for TBEV. Borrelia prevalence was 25.0% for adults (n=44) and the minimum infection rate (MIR) 5.6% for pooled nymph samples (191 samples, 1-14 individuals per sample; 30/191 positive). No Borrelia were detected in pooled larval samples (63 samples, 1-139 individuals per sample). Five species of Borrelia were identified from the samples: B. afzelii, B. burgdorferi s.s., B. garinii, B. valaisiana and B. miyamotoi. In Finland, B. valaisiana and B. miyamotoi have previously been reported from the Åland Islands but not from the mainland or inner archipelago. The results of the present study suggest an increase in I. ricinus abundance on the island.
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Jääskeläinen A, Tonteri E, Pieninkeroinen I, Sironen T, Voutilainen L, Kuusi M, Vaheri A, Vapalahti O. Siberian subtype tick-borne encephalitis virus in Ixodes ricinus in a newly emerged focus, Finland. Ticks Tick Borne Dis 2015; 7:216-223. [PMID: 26548609 DOI: 10.1016/j.ttbdis.2015.10.013] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 09/28/2015] [Accepted: 10/16/2015] [Indexed: 11/26/2022]
Abstract
The first tick-borne encephalitis (TBE) cases in Kotka, Finland appeared in 2010. Altogether ten human cases have been diagnosed by 2014. Four had long-lasting sequelae. We collected 195 Ixodes ricinus ticks, nine rodents, and eleven shrews from the archipelago of Kotka in 2011. Three Siberian subtype TBE virus (TBEV) strains were isolated from the ticks and three mammals were positive for TBEV antibodies. The archipelago of Kotka is a newly emerged TBE focus of Siberian subtype TBEV circulating notably in I. ricinus. The patients had on average longer hospitalization than reported for the European subtype infection.
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Affiliation(s)
- Anu Jääskeläinen
- Department of Virology, University of Helsinki, P.O. Box 21, FI-00014 Helsinki, Finland.
| | - Elina Tonteri
- Department of Virology, University of Helsinki, P.O. Box 21, FI-00014 Helsinki, Finland.
| | | | - Tarja Sironen
- Department of Virology, University of Helsinki, P.O. Box 21, FI-00014 Helsinki, Finland.
| | - Liina Voutilainen
- Department of Virology, University of Helsinki, P.O. Box 21, FI-00014 Helsinki, Finland; Natural Resources Institute, Vantaa Unit, P.O. Box 18, FI-01301 Vantaa, Finland.
| | - Markku Kuusi
- Department of Infectious Diseases, National Institute for Health and Welfare, P.O. Box 30, FI-00271 Helsinki, Finland.
| | - Antti Vaheri
- Department of Virology, University of Helsinki, P.O. Box 21, FI-00014 Helsinki, Finland; Department of Virology and Immunology, HUSLAB, Helsinki University Hospital, P.O. Box 400, FI-00029 Helsinki, Finland.
| | - Olli Vapalahti
- Department of Virology, University of Helsinki, P.O. Box 21, FI-00014 Helsinki, Finland; Department of Virology and Immunology, HUSLAB, Helsinki University Hospital, P.O. Box 400, FI-00029 Helsinki, Finland; Department of Veterinary Biosciences, University of Helsinki, P.O. Box 66, FI-00014 Helsinki, Finland.
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31
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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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Bioluminescent detection probe for tick-borne encephalitis virus immunoassay. Anal Bioanal Chem 2015; 407:5417-23. [DOI: 10.1007/s00216-015-8710-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 04/06/2015] [Accepted: 04/15/2015] [Indexed: 12/30/2022]
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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: 45] [Impact Index Per Article: 5.0] [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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Steffen R, Behrens RH, Hill DR, Greenaway C, Leder K. Vaccine-preventable travel health risks: what is the evidence--what are the gaps? J Travel Med 2015; 22:1-12. [PMID: 25378212 DOI: 10.1111/jtm.12171] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 08/02/2014] [Accepted: 09/08/2014] [Indexed: 11/30/2022]
Abstract
BACKGROUND Existing travel health guidelines are based on a variety of data with underpinning evidence ranging from high-quality randomized controlled trials to best estimates from expert opinion. For strategic guidance and to set overall priorities, data about average risk are useful. The World Health Organization (WHO) plans to base future editions of "International Travel and Health" on its new "Handbook for Guideline Development." METHODS Based on a systematic search in PubMed, the existing evidence and quality of data on vaccine-preventable disease (VPD) risks in travelers was examined and essentials of vaccine efficacy were briefly reviewed. The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) framework was used to evaluate the quality of the data. RESULTS Moderate-quality data to determine the risk of VPD exist on those that are frequently imported, whereas in most others the level of confidence with existing data is low or very low. CONCLUSIONS In order for the WHO to produce graded risk statements in the updated version of "International Travel and Health," major investment of time plus additional high-quality, generalizable risk data are needed.
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Affiliation(s)
- Robert Steffen
- Department of Public Health, Epidemiology, Biostatistics and Prevention Institute, University of Zurich, WHO Collaborating Centre for Traveller's Health, Zurich, Switzerland
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Abstract
In this chapter, we describe 73 zoonotic viruses that were isolated in Northern Eurasia and that belong to the different families of viruses with a single-stranded RNA (ssRNA) genome. The family includes viruses with a segmented negative-sense ssRNA genome (families Bunyaviridae and Orthomyxoviridae) and viruses with a positive-sense ssRNA genome (families Togaviridae and Flaviviridae). Among them are viruses associated with sporadic cases or outbreaks of human disease, such as hemorrhagic fever with renal syndrome (viruses of the genus Hantavirus), Crimean–Congo hemorrhagic fever (CCHFV, Nairovirus), California encephalitis (INKV, TAHV, and KHATV; Orthobunyavirus), sandfly fever (SFCV and SFNV, Phlebovirus), Tick-borne encephalitis (TBEV, Flavivirus), Omsk hemorrhagic fever (OHFV, Flavivirus), West Nile fever (WNV, Flavivirus), Sindbis fever (SINV, Alphavirus) Chikungunya fever (CHIKV, Alphavirus) and others. Other viruses described in the chapter can cause epizootics in wild or domestic animals: Geta virus (GETV, Alphavirus), Influenza A virus (Influenzavirus A), Bhanja virus (BHAV, Phlebovirus) and more. The chapter also discusses both ecological peculiarities that promote the circulation of these viruses in natural foci and factors influencing the occurrence of epidemic and epizootic outbreaks
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Šmit R, Postma MJ. Review of tick-borne encephalitis and vaccines: clinical and economical aspects. Expert Rev Vaccines 2014; 14:737-47. [DOI: 10.1586/14760584.2015.985661] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Palo RT. Tick-borne encephalitis transmission risk: its dependence on host population dynamics and climate effects. Vector Borne Zoonotic Dis 2014; 14:346-52. [PMID: 24745813 DOI: 10.1089/vbz.2013.1386] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Tick-borne encephalitis (TBE) is a human disease caused by a flavivirus that is spread by ticks (Ixodes ricinus). In 2011 and 2012, the highest TBE incidence ever was recorded in Sweden. It has been proposed that warmer spring temperatures result in higher survival of ticks and thus high incidence of TBE. Here, analyses were done of time series of TBE for 1976-2011 in relation to the North Atlantic Oscillation (NAO), mean summer temperatures, and yearly number of harvested European hare (Lepus europeaus), roe deer (Capreolus capreolus), and red fox (Vulpes vulpes) in the County of Stockholm, the area with most TBE cases in recent years in Sweden. The results show that the winter NAO index or winter temperature has no significant effect on the variation in wildlife numbers harvested or TBE cases over time. Mean summer temperature above 12°C had a slight effect, but a multivariate model revealed that only the numbers of European hare and red fox remained in the model and explained 64.4% of the variation in TBE cases. Ticks do not seem to be as sensitive to climate variations as anticipated, even though that summer temperature has increased by 2°C during the time period studied here. Instead, TBE cases seem to be more dependent on host population dynamics than on climate factors.
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Affiliation(s)
- R Thomas Palo
- Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences , 901 87, Umeå, Sweden
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Pettersson JHO, Golovljova I, Vene S, Jaenson TGT. Prevalence of tick-borne encephalitis virus in Ixodes ricinus ticks in northern Europe with particular reference to Southern Sweden. Parasit Vectors 2014; 7:102. [PMID: 24618209 PMCID: PMC4007564 DOI: 10.1186/1756-3305-7-102] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Accepted: 02/16/2014] [Indexed: 12/30/2022] Open
Abstract
Background In northern Europe, the tick-borne encephalitis virus (TBEV) of the European subtype is usually transmitted to humans by the common tick Ixodes ricinus. The aims of the present study are (i) to obtain up-to-date information on the TBEV prevalence in host-seeking I. ricinus in southern and central Sweden; (ii) to compile and review all relevant published records on the prevalence of TBEV in ticks in northern Europe; and (iii) to analyse and try to explain how the TBE virus can be maintained in natural foci despite an apparently low TBEV infection prevalence in the vector population. Methods To estimate the mean minimum infection rate (MIR) of TBEV in I. ricinus in northern Europe (i.e. Denmark, Norway, Sweden and Finland) we reviewed all published TBEV prevalence data for host-seeking I. ricinus collected during 1958–2011. Moreover, we collected 2,074 nymphs and 906 adults of I. ricinus from 29 localities in Sweden during 2008. These ticks were screened for TBEV by RT-PCR. Results The MIR for TBEV in nymphal and adult I. ricinus was 0.28% for northern Europe and 0.23% for southern Sweden. The infection prevalence of TBEV was significantly lower in nymphs (0.10%) than in adult ticks (0.55%). At a well-known TBEV-endemic locality, Torö island south-east of Stockholm, the TBEV prevalence (MIR) was 0.51% in nymphs and 4.48% in adults of I. ricinus. Conclusions If the ratio of nymphs to adult ticks in the TBEV-analysed sample differs from that in the I. ricinus population in the field, the MIR obtained will not necessarily reflect the TBEV prevalence in the field. The relatively low TBEV prevalence in the potential vector population recorded in most studies may partly be due to: (i) inclusion of uninfected ticks from the ‘uninfected areas’ surrounding the TBEV endemic foci; (ii) inclusion of an unrepresentative, too large proportion of immature ticks, compared to adult ticks, in the analysed tick pools; and (iii) shortcomings in the laboratory techniques used to detect the virus that may be present in a very low concentration or undetectable state in ticks which have not recently fed.
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Affiliation(s)
| | | | | | - Thomas G T Jaenson
- Medical Entomology Unit, Subdepartment of Systematic Biology, Department of Organismal Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18d, SE-752 36, Uppsala, Sweden.
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Diagnostic potential and antigenic properties of recombinant tick-borne encephalitis virus subviral particles expressed in mammalian cells from Semliki Forest virus replicons. J Clin Microbiol 2013; 52:814-22. [PMID: 24371235 DOI: 10.1128/jcm.02488-13] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The precursor membrane envelope (prME) proteins of all three tick-borne encephalitis virus (TBEV) subtypes were produced based on expression from Semliki Forest virus (SFV) replicons transcribed from recombinant plasmids. Vero E6 cells transfected by these plasmids showed specific reactivities in immunofluorescence and immunoblot assays by monoclonal antibodies against European and Far-Eastern subtype strains of TBEV, indicating proper folding of the expressed glycoproteins. The prME glycoproteins were secreted into the cell culture supernatant, forming TBEV subviral particles of 20 to 30 nm in diameter. IgM μ-capture and IgG monoclonal antibody (MAb)-capture enzyme immunoassays (EIAs) were developed based on prME Karelia-94 (Siberian subtype) particles. Altogether, 140 human serum samples were tested using these assays, and the results were compared to those obtained with a commercial IgM EIA, an in-house μ-capture IgM assay based on baculovirus-expressed antigen, a commercial IgG EIA, and a hemagglutination inhibition test. Compared to reference enzyme-linked immunosorbent assays (ELISAs), the sensitivities of the generated μ-capture IgM SFV-prME and IgG MAb-capture SFV-prME EIAs were 97.4 to 100% and 98.7%, respectively, and the specificities of the two assays were 100%. IgM and IgG immunofluorescence assays (IFAs) were created based on Vero E6 cells transfected with the recombinant plasmid carrying the TBEV Karelia-94 prME glycoproteins. The IgM IFA was 100% concordant with the μ-capture IgM bac-prME ELISA. The IgG IFA sensitivity and specificity were 98.7% and 100%, respectively, compared to those of the commercial ELISA. In conclusion, the tests developed based on SFV replicon-driven expression of TBEV glycoproteins provide safe and robust alternatives for conducting TBEV serology.
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The three subtypes of tick-borne encephalitis virus induce encephalitis in a natural host, the bank vole (Myodes glareolus). PLoS One 2013; 8:e81214. [PMID: 24349041 PMCID: PMC3862475 DOI: 10.1371/journal.pone.0081214] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 10/09/2013] [Indexed: 12/30/2022] Open
Abstract
Tick-borne encephalitis virus (TBEV) infects bank voles (Myodes glareolus) in nature, but the relevance of rodents for TBEV transmission and maintenance is unclear. We infected colonized bank voles subcutaneously to study and compare the infection kinetics, acute infection, and potential viral persistence of the three known TBEV subtypes: European (TBEV-Eur), Siberian (TBEV-Sib) and Far Eastern (TBEV-FE). All strains representing the three subtypes were infective and highly neurotropic. They induced (meningo)encephalitis in some of the animals, however most of the cases did not present with apparent clinical symptoms. TBEV-RNA was cleared significantly slower from the brain as compared to other organs studied. Supporting our earlier findings in natural rodent populations, TBEV-RNA could be detected in the brain for up to 168 days post infection, but we could not demonstrate infectivity by cell culture isolation. Throughout all time points post infection, RNA of the TBEV-FE was detected significantly more often than RNA of the other two strains in all organs studied. TBEV-FE also induced prolonged viremia, indicating distinctive kinetics in rodents in comparison to the other two subtypes. This study shows that bank voles can develop a neuroinvasive TBEV infection with persistence of viral RNA in brain, and mount an anti-TBEV IgG response. The findings also provide further evidence that bank voles can serve as sentinels for TBEV endemicity.
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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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Amicizia D, Domnich A, Panatto D, Lai PL, Cristina ML, Avio U, Gasparini R. Epidemiology of tick-borne encephalitis (TBE) in Europe and its prevention by available vaccines. Hum Vaccin Immunother 2013; 9:1163-71. [PMID: 23377671 PMCID: PMC3899155 DOI: 10.4161/hv.23802] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 01/21/2013] [Accepted: 01/28/2013] [Indexed: 12/30/2022] Open
Abstract
Tick-borne Encephalitis (TBE), which is caused by a Flavivirus, is the most common tick-transmitted disease in Central and Eastern Europe and Russia. Today, TBE is endemic in 27 European countries, and has become an international public health problem. The epidemiology of TBE is changing owing to various factors, such as improvements in diagnosis and case reporting, increased recreational activities in areas populated by ticks, and changes in climatic conditions affecting tick habitats. Vaccination remains the most effective protective measure against TBE for people living in risk zones, occupationally exposed subjects and travelers to endemic areas. The vaccines currently in use are FSME-Immun(®), Encepur(®), EnceVir(®) and TBE vaccine Moscow(®). The numerous studies performed on the efficacy and safety of these vaccines have shown a high level of immunogenicity and an excellent safety profile. Several studies have also shown a high level of cross-protection among strains belonging to different subtypes. In the present paper we attempted to describe the continuously changing epidemiology of TBE in European States and to overview clinical development of available vaccines paying particular attention on cross-protection elicited by the vaccines.
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Affiliation(s)
- Daniela Amicizia
- Department of Health Sciences; University of Genoa; Genoa, Italy
| | | | | | - Piero Luigi Lai
- Department of Health Sciences; University of Genoa; Genoa, Italy
| | | | - Ulderico Avio
- Business Unit Manager Vaccines; Baxter S.p.A.; Rome, Italy
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Geller J, Nazarova L, Katargina O, Leivits A, Järvekülg L, Golovljova I. Tick-borne pathogens in ticks feeding on migratory passerines in Western part of Estonia. Vector Borne Zoonotic Dis 2013; 13:443-8. [PMID: 23590318 DOI: 10.1089/vbz.2012.1054] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
During southward migration in the years 2006-2009, 178 migratory passerines of 24 bird species infested with ticks were captured at bird stations in Western Estonia. In total, 249 nymphal ticks were removed and analyzed individually for the presence of Borrelia burgdorferi sensu lato (s.l.), tick-borne encephalitis virus (TBEV), and Anaplasma phagocytophilum. The majority of ticks were collected from Acrocephalus (58%), Turdus (13%), Sylvia (8%), and Parus (6%) bird species. Tick-borne pathogens were detected in nymphs removed from Acrocephalus, Turdus, and Parus bird species. TBEV of the European subtype was detected in 1 I. ricinus nymph removed from A. palustris. B. burgdorferi s.l. DNA was found in 11 ticks (4.4%) collected from Turdus and Parus species. Bird-associated B. garinii and B. valaisiana were detected in I. ricinus nymphs removed from T. merula. Rodent-associated B. afzelii was detected in 3 I. ricinus nymphs from 2 P. major birds. One of the B. afzelii-positive nymphs was infected with a mix of 2 B. afzelii strains, whereas 1 of these strains was also detected in another nymph feeding on the same great tit. The sharing of the same B. afzelii strain by 2 nymphs indicates a possible transmission of B. afzelii by co-feeding on a bird. A. phagocytophilum DNA was detected in 1 I. ricinus nymph feeding on a T. iliacus. The results of the study confirm the possible role of migratory birds in the dispersal of ticks infected with tick-borne pathogens along the southward migration route via Estonia.
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Affiliation(s)
- Julia Geller
- National Institute for Health Development, Tallinn, Estonia
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Jaenson TGT, Hjertqvist M, Bergström T, Lundkvist A. Why is tick-borne encephalitis increasing? A review of the key factors causing the increasing incidence of human TBE in Sweden. Parasit Vectors 2012; 5:184. [PMID: 22937961 PMCID: PMC3439267 DOI: 10.1186/1756-3305-5-184] [Citation(s) in RCA: 134] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2012] [Accepted: 08/17/2012] [Indexed: 12/30/2022] Open
Abstract
The highest annual incidence of human tick-borne encephalitis (TBE) in Sweden ever recorded by the Swedish Institute for Communicable Disease Control (SMI) occurred last year, 2011. The number of TBE cases recorded during 2012 up to 6th August 2012 indicates that the incidence for 2012 could exceed that of 2011. In this review of the ecology and epidemiology of TBE in Sweden our main aim is to analyse the possible reasons behind the gradually increasing incidence of human TBE during the last 20 years. The main TBE virus (TBEV) vector to humans in Sweden is the nymphal stage of the common tick Ixodes ricinus. The main mode of transmission and maintenance of TBEV in the tick population is considered to be when infective nymphs co-feed with uninfected but infectible larvae on rodents. In most locations the roe deer, Capreolus capreolus is the main host for the reproducing adult I. ricinus ticks. The high number of roe deer for more than three decades has resulted in a very large tick population. Deer numbers have, however, gradually declined from the early 1990s to the present. This decline in roe deer numbers most likely made the populations of small rodents, which are reservoir-competent for TBEV, gradually more important as hosts for the immature ticks. Consequently, the abundance of TBEV-infected ticks has increased. Two harsh winters in 2009-2011 caused a more abrupt decline in roe deer numbers. This likely forced a substantial proportion of the "host-seeking" ticks to feed on bank voles (Myodes glareolus), which at that time suddenly had become very numerous, rather than on roe deer. Thus, the bank vole population peak in 2010 most likely caused many tick larvae to feed on reservoir-competent rodents. This presumably resulted in increased transmission of TBEV among ticks and therefore increased the density of infected ticks the following year. The unusually warm, humid weather and the prolonged vegetation period in 2011 permitted nymphs and adult ticks to quest for hosts nearly all days of that year. These weather conditions stimulated many people to spend time outdoors in areas where they were at risk of being attacked by infective nymphs. This resulted in at least 284 human cases of overt TBE. The tick season of 2012 also started early with an exceptionally warm March. The abundance of TBEV-infective "hungry" ticks was presumably still relatively high. Precipitation during June and July was rich and will lead to a "good mushroom season". These factors together are likely to result in a TBE incidence of 2012 similar to or higher than that of 2011.
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Affiliation(s)
- Thomas G T Jaenson
- Medical Entomology Unit, Department of Systematic Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18d, Uppsala SE-752 36, Sweden.
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Abstract
The aim of this review is to present briefly background information on 27 tick-borne viruses ("tiboviruses") that have been detected in Europe, viz flaviviruses tick-borne encephalitis (TBEV), louping-ill (LIV), Tyuleniy (TYUV), and Meaban (MEAV); orthobunyaviruses Bahig (BAHV) and Matruh (MTRV); phleboviruses Grand Arbaud (GAV), Ponteves (PTVV), Uukuniemi (UUKV), Zaliv Terpeniya (ZTV), and St. Abb's Head (SAHV); nairoviruses Soldado (SOLV), Puffin Island (PIV), Avalon (AVAV), Clo Mor (CMV), Crimean-Congo hemorrhagic fever (CCHFV); bunyavirus Bhanja (BHAV); coltivirus Eyach (EYAV); orbiviruses Tribec (TRBV), Okhotskiy (OKHV), Cape Wrath (CWV), Mykines (MYKV), Tindholmur (TDMV), and Bauline (BAUV); two thogotoviruses (Thogoto THOV, Dhori DHOV); and one asfivirus (African swine fever virus ASFV). Emphasis is laid on the taxonomic status of these viruses, range of their ixodid or argasid vectors and vertebrate hosts, pathogenicity for vertebrates including humans, and relevance to public health. In general, three groups of tibovirus diseases can be recognized according to main clinical symptoms produced: (i) febrile illness-usually with a rapid onset, fever, sweating, headache, nausea, weakness, myalgia, arthralgia, sometimes polyarthritis and rash; (ii) the CNS affection-meningitis, meningoencephalitis or encephalomyelitis with pareses, paralysis and other sequelae; (iii) hemorrhagic disease. Several "European" tiboviruses cause very serious human (TBEV, CCHFV) or animal (LIV, ASFV) diseases. Other arboviruses play definite role in human or animal pathology though the disease is usually either less serious or infrequently reported (TYUV, BHAV, AVAV, EYAV, TRBV, DHOV, THOV). The other European arboviruses are "orphans" without a proven medical or veterinary significance (BAHV, MTRV, MEAV, GAV, PTVV, ZTV, SAHV, UUKV, SOLV, PIV, AVAV, CMV, OKHV, CWV, MYKV, TDMV, BAUV). However, certain arbovirus diseases of free-living vertebrates (but also those of domestic animals and even man) may often pass unnoticed or misdiagnosed and eventually, they might potentially appear as emerging diseases. Active search for new tiboviruses or for new, pathogenic variants of the known tiboviruses in Europe should therefore continue.
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Affiliation(s)
- Zdenek Hubálek
- Institute of Vertebrate Biology, v.v.i., Academy of Sciences of the Czech Republic, Květná 8, 60365, Brno, Czech Republic.
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Uzcátegui NY, Sironen T, Golovljova I, Jääskeläinen AE, Välimaa H, Lundkvist Å, Plyusnin A, Vaheri A, Vapalahti O. Rate of evolution and molecular epidemiology of tick-borne encephalitis virus in Europe, including two isolations from the same focus 44 years apart. J Gen Virol 2012; 93:786-796. [DOI: 10.1099/vir.0.035766-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Tick-borne encephalitis virus (TBEV) is a member of the family Flaviviridae. It is transmitted by Ixodes spp. ticks in a cycle involving rodents and small mammals. TBEV has three subtypes: European, Siberian and Far Eastern. The virus causes thousands of cases of meningoencephalitis in Europe annually, with an increasing trend. The increase may be attributed to a complex network of elements, including climatic, environmental and socio-economic factors. In an attempt to understand the evolutionary history and dispersal of TBEV, to existing genetic data we add two novel complete ORF sequences of TBEV strains from northern Europe and the completion of the genome of four others. Moreover, we provide a unique measure for the natural rate of evolution of TBEV by studying two isolations from the same forest on an island in Åland archipelago 44 years apart. For all isolates, we analysed the phylogeny, rate of evolution and probable time of radiation of the different TBEV strains. The results show that the two lineages of TBEV in different Ixodes species have evolved independently for approximately 3300 years. Notably, rapid radiation of TBEV-Eur occurred approximately 300 years ago, without the large-scale geographical clustering observed previously for the Siberian subtype. The measurements from the natural rate of evolution correlated with the estimates done by phylogenetic programs, demonstrating their robustness.
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Affiliation(s)
- Nathalie Y. Uzcátegui
- Infection Biology Research Program, Department of Virology, Haartman Institute, PO Box 21, FI-00014 University of Helsinki, Helsinki, Finland
| | - Tarja Sironen
- Infection Biology Research Program, Department of Virology, Haartman Institute, PO Box 21, FI-00014 University of Helsinki, Helsinki, Finland
| | - Irina Golovljova
- Department of Virology, National Institute for Health Development, EE-11619 Tallinn, Estonia
- Center for Microbiological Preparedness, Swedish Institute for Infectious Disease Control, SE-17182 Solna, Sweden
| | - Anu E. Jääskeläinen
- Infection Biology Research Program, Department of Virology, Haartman Institute, PO Box 21, FI-00014 University of Helsinki, Helsinki, Finland
| | - Hannamari Välimaa
- Department of Virology, Helsinki University Hospital Laboratory (HUSLAB), PO Box 400, FI-00029 HUS, Helsinki, Finland
- Infection Biology Research Program, Department of Virology, Haartman Institute, PO Box 21, FI-00014 University of Helsinki, Helsinki, Finland
| | - Åke Lundkvist
- Center for Microbiological Preparedness, Swedish Institute for Infectious Disease Control, SE-17182 Solna, Sweden
| | - Alexander Plyusnin
- Infection Biology Research Program, Department of Virology, Haartman Institute, PO Box 21, FI-00014 University of Helsinki, Helsinki, Finland
| | - Antti Vaheri
- Department of Virology, Helsinki University Hospital Laboratory (HUSLAB), PO Box 400, FI-00029 HUS, Helsinki, Finland
- Infection Biology Research Program, Department of Virology, Haartman Institute, PO Box 21, FI-00014 University of Helsinki, Helsinki, Finland
| | - Olli Vapalahti
- Department of Basic Veterinary Sciences, Faculty of Veterinary Medicine, PO Box 66, FI-00014 University of Helsinki, Helsinki, Finland
- Department of Virology, Helsinki University Hospital Laboratory (HUSLAB), PO Box 400, FI-00029 HUS, Helsinki, Finland
- Infection Biology Research Program, Department of Virology, Haartman Institute, PO Box 21, FI-00014 University of Helsinki, Helsinki, Finland
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47
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Dodd KA, Bird BH, Khristova ML, Albariño CG, Carroll SA, Comer JA, Erickson BR, Rollin PE, Nichol ST. Ancient ancestry of KFDV and AHFV revealed by complete genome analyses of viruses isolated from ticks and mammalian hosts. PLoS Negl Trop Dis 2011; 5:e1352. [PMID: 21991403 PMCID: PMC3186760 DOI: 10.1371/journal.pntd.0001352] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Accepted: 08/25/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Alkhurma hemorrhagic fever virus (AHFV) and Kyasanur forest disease virus (KFDV) cause significant human disease and mortality in Saudi Arabia and India, respectively. Despite their distinct geographic ranges, AHFV and KFDV share a remarkably high sequence identity. Given its emergence decades after KFDV, AHFV has since been considered a variant of KFDV and thought to have arisen from an introduction of KFDV to Saudi Arabia from India. To gain a better understanding of the evolutionary history of AHFV and KFDV, we analyzed the full length genomes of 16 AHFV and 3 KFDV isolates. METHODOLOGY/PRINCIPAL FINDINGS Viral genomes were sequenced and compared to two AHFV sequences available in GenBank. Sequence analyses revealed higher genetic diversity within AHFVs isolated from ticks than human AHFV isolates. A Bayesian coalescent phylogenetic analysis demonstrated an ancient divergence of AHFV and KFDV of approximately 700 years ago. CONCLUSIONS/SIGNIFICANCE The high sequence diversity within tick populations and the presence of competent tick vectors in the surrounding regions, coupled with the recent identification of AHFV in Egypt, indicate possible viral range expansion or a larger geographic range than previously thought. The divergence of AHFV from KFDV nearly 700 years ago suggests other AHFV/KFDV-like viruses might exist in the regions between Saudi Arabia and India. Given the human morbidity and mortality associated with these viruses, these results emphasize the importance of more focused study of these significant public health threats.
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Affiliation(s)
- Kimberly A. Dodd
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
- School of Veterinary Medicine, University of California Davis, Davis, California, United States of America
| | - Brian H. Bird
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Marina L. Khristova
- Biotechnology Core Facility Branch, Division of Scientific Resources, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - César G. Albariño
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Serena A. Carroll
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - James A. Comer
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Bobbie R. Erickson
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Pierre E. Rollin
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Stuart T. Nichol
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
- * E-mail:
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48
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Orlinger KK, Hofmeister Y, Fritz R, Holzer GW, Falkner FG, Unger B, Loew-Baselli A, Poellabauer EM, Ehrlich HJ, Barrett PN, Kreil TR. A Tick-borne Encephalitis Virus Vaccine Based on the European Prototype Strain Induces Broadly Reactive Cross-neutralizing Antibodies in Humans. J Infect Dis 2011; 203:1556-64. [DOI: 10.1093/infdis/jir122] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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49
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Jääskeläinen AE, Tonteri E, Sironen T, Pakarinen L, Vaheri A, Vapalahti O. European subtype tick-borne encephalitis virus in Ixodes persulcatus ticks. Emerg Infect Dis 2011; 17:323-5. [PMID: 21291624 PMCID: PMC3376769 DOI: 10.3201/eid1702.101487] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
MESH Headings
- Animals
- Arthropod Vectors/virology
- Arvicolinae/virology
- Communicable Diseases, Emerging/epidemiology
- Communicable Diseases, Emerging/transmission
- Communicable Diseases, Emerging/virology
- Encephalitis Viruses, Tick-Borne/genetics
- Encephalitis Viruses, Tick-Borne/immunology
- Encephalitis Viruses, Tick-Borne/isolation & purification
- Encephalitis, Tick-Borne/epidemiology
- Encephalitis, Tick-Borne/transmission
- Encephalitis, Tick-Borne/virology
- Finland/epidemiology
- Humans
- Ixodes/virology
- Mice
- Phylogeny
- Prevalence
- RNA, Viral/blood
- Rodent Diseases/epidemiology
- Rodent Diseases/transmission
- Rodent Diseases/virology
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50
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Weidmann M, Růžek D, Křivanec K, Zöller G, Essbauer S, Pfeffer M, Zanotto PMDA, Hufert FT, Dobler G. Relation of genetic phylogeny and geographical distance of tick-borne encephalitis virus in central Europe. J Gen Virol 2011; 92:1906-1916. [PMID: 21593276 DOI: 10.1099/vir.0.032417-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Tick-borne encephalitis virus (TBEV) is the most important arboviral agent causing disease of the central nervous system in central Europe. In this study, 61 TBEV E gene sequences derived from 48 isolates from the Czech Republic, and four isolates and nine TBEV strains detected in ticks from Germany, covering more than half a century from 1954 to 2009, were sequenced and subjected to phylogenetic and Bayesian phylodynamic analysis to determine the phylogeography of TBEV in central Europe. The general Eurasian continental east-to-west pattern of the spread of TBEV was confirmed at the regional level but is interlaced with spreading that arises because of local geography and anthropogenic influence. This spread is reflected by the disease pattern in the Czech Republic that has been observed since 1991. The overall evolutionary rate was estimated to be approximately 8×10(-4) substitutions per nucleotide per year. The analysis of the TBEV E genes of 11 strains isolated at one natural focus in žďár Kaplice proved for the first time that TBEV is indeed subject to local evolution.
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Affiliation(s)
- M Weidmann
- Department of Virology, University Medical Center Göttingen, Germany
| | - D Růžek
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic
| | - K Křivanec
- Central Military Institute of Health, Army Forces of the Czech Republic, České Budějovice, Czech Republic
| | - G Zöller
- Bundeswehr Institute of Microbiology, Munich, Germany
| | - S Essbauer
- Bundeswehr Institute of Microbiology, Munich, Germany
| | - M Pfeffer
- Institute of Animal Hygiene and Veterinary Public Health, University of Leipzig, Leipzig, Germany
| | - P M de A Zanotto
- Department of Microbiology, University of São Paulo, Biomedical Sciences Institute - ICB II, São Paulo, Brazil
| | - F T Hufert
- Department of Virology, University Medical Center Göttingen, Germany
| | - G Dobler
- Bundeswehr Institute of Microbiology, Munich, Germany
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