scholarly journals Tick-Borne Encephalitis Virus Habitats in North East Germany: Reemergence of TBEV in Ticks after 15 Years of Inactivity

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Silvius Frimmel ◽  
Anja Krienke ◽  
Diana Riebold ◽  
Micha Loebermann ◽  
Martina Littmann ◽  
...  

The incidence of tick-borne encephalitis has risen in Europe since 1990 and the tick-borne encephalitis virus (TBEV) has been documented to be spreading into regions where it was not previously endemic. In Mecklenburg-West Pomerania, a federal state in Northern Germany, TBEV was not detectable in over 16,000 collected ticks between 1992 and 2004. Until 2004, the last human case of TBE in the region was reported in 1985. Following the occurrence of three autochthonous human cases of TBE after 2004, however, we collected ticks from the areas in which the infections were contracted. To increase the chance of detecting TBEV-RNA, some of the ticks were fed on mice. Using nested RT-PCR, we were able to confirm the presence of TBEV in ticks for the first time after 15 years. A phylogenetic analysis revealed a close relationship between the sequences we obtained and a TBEV sequence from Mecklenburg-East Pomerania published in 1992 and pointed to the reemergence of a natural focus of TBEV after years of low activity. Our results imply that natural foci of TBEV may either persist at low levels of activity for years or reemerge through the agency of migrating birds.

Author(s):  
Joon Young Song

Although no human case of tick-borne encephalitis (TBE) has been documented in South Korea to date, surveillance studies have been conducted to evaluate the prevalence of tick-borne encephalitis virus (TBEV) in wild ticks.


2011 ◽  
Vol 92 (8) ◽  
pp. 1906-1916 ◽  
Author(s):  
M. Weidmann ◽  
D. Růžek ◽  
K. Křivanec ◽  
G. Zöller ◽  
S. Essbauer ◽  
...  

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.


2018 ◽  
Vol 8 (3) ◽  
pp. 335-340
Author(s):  
A. O. Turanov ◽  
A. Y. Nikitin ◽  
E. I. Andaev

Studying of immune interlayer value to tick-borne encephalitis virus in human population of the Transbaikalia Territory resulted from natural immunization of the healthy population in 31 Municipal areas in 2011–2016 is presented. Human selections were formed proportionally to the population size in the concrete human settlement among persons of the various age and professional groups living at this territory not less than 10 years and unvaccinated against tick-borne encephalitis virus. Total 4367 blood sera were investigated. Laboratory testing for antibodies of G class to tick-borne encephalitis virus in blood sera of the human population was performed by immune-enzyme analysis using a set of reagents “VektoVKE-IgG” of Joint-Stock Company “Vektor-Best” (Novosibirsk city). The monitoring data indicated the presence of natural immunity to tick-borne encephalitis virus in the human population. Mean annual level of immune interlayer in Municipal areas varied from 3.1 to 52.7% (in Transbaikalian Territory — 13.1±0.51%). High level (from 20 to 52.7%) was characteristic for mountain-taiga-forest-steppe zone (Krasnochikoisky — 23.8±3.36%; Uletovsky — 52.4±4.48%; Gazimuro-Zavodsky — 29.4±4.94% districts) and mountain-tundra-taiga zone (Tungokochensky district — 20.0±3.58%). In steppe zone the level of immune interlayer was lower and observed in districts with elements of south-taiga larch and pine forests. It was established that levels of the immune interlayer in human population living in mountain-taiga-foreststeppe and mountain-tundra-taiga zones authentically higher than in steppe area — t = 3.8; Р < 0.001 and t = 2.27; Р < 0.05, respectively. Distinctions in the value of the immune interlayer between mountain-tundra-taiga and mountain-taigaforest-steppe zones were non-authentic: t = 0.1; P > 0.05. Active circulation of tick-borne encephalitis virus was accompanied by authentic (Р < 0.01) increase of the interlayer in persons with the virus antibodies in 2014–2016 (15.8±0.69%) in comparison with 2011–2013 (9.7±0.78%). Also it was noted in all landscape zones: in steppe zone the increase was to 42.8% (P > 0.05); in mountain-taiga-forest-steppe — to 61.3% (P > 0.05); in mountain-tundra-taiga — to 150.0% (Р < 0.01). It was not possible to reveal correlation between the recourse for medical aid and the value of immune interlayer in the population formed as a result of latent immunization. Results of the population immunity studying essentially expand our knowledge about the condition of the natural foci and dynamics of development of the epidemic processes in it, and can be used at planning of the preventive actions.


2017 ◽  
Vol 62 (1) ◽  
pp. 30-35 ◽  
Author(s):  
N. M. Pukhovskaya ◽  
O. V. Morozova ◽  
N. B. Belozerova ◽  
S. V. Bakhmetyeva ◽  
N. P. Vysochina ◽  
...  

The tick-borne encephalitis virus (TBEV) strain Lazo MP36 was isolated from the pool of mosquitoes Aedes vexans collected in Lazo region of Khabarovsk territory in August 2014. Phylogenetic analysis of the strain Lazo MP36 complete genome (GenBank accession number KT001073) revealed its correspondence to the TBEV Far Eastern subtype and differences from the following strains: 1) from ticks Ixodes persulcatus P. Schulze, 1930 [vaccine strain 205 (JX498939) and strains Khekhtzir 1230 (KF880805), Chichagovka (KP844724), Birobidzhan 1354 (KF880805) isolated in 2012-2013]; 2) from mosquitoes [strain Malyshevo (KJ744034) isolated in 1978 from Aedes vexans nipponii in Khabarovsk territory; strain Sakhalin 6-11 isolated from the pool of mosquitoes in 2011 (KF826916)]; 3) from human brain [vaccine strain Sofjin (JN229223), Glubinnoe/2004(DQ862460). Kavalerovo (DQ862460), Svetlogorie (DQ862460)]. The fusion peptide necessary for flavivirus entry to cells of the three TBEV strains isolated from mosquitoes (Lazo MP36, Malyshevo and Sakhalin 6-11) has the canonical structure 98-DRGWGNHCGLFGKGSI-113 for the tick-borne flaviviruses. Amino acid transition H104G typical for the mosquito-borne flaviviruses was not found. Structures of 5’- and 3’-untranslated (UTR) regions of the TBEV strains from mosquitoes were 85-98% homologous to the TBEV strains of all subtypes without recombination with mosquito-borne flaviviruses found in the Far East of Russia. Secondary structures of 5’- and 3'-UTR as well as cyclization sequences (CS) of types a and B are highly homologous for all TBEV isolates independently of the biological hosts and vectors. similarity of the genomes of the TBEV isolates from mosquitoes, ticks and patients as well as pathogenicity of the isolates for new-borne laboratory mice and tissue cultures might suggest a possible role of mosquitoes in the TBEV circulation in natural foci as an accidental or additional virus carrier.


Author(s):  
Yves Hansmann ◽  
Aurélie Velay

The first human case of tick-borne encephalitis virus (TBEV) infection in France was reported in 1968 in Alsace, an eastern region next to the German border: a gamekeeper working in a forest near Strasbourg.


Almost the entire territory of Belarus is believed to be endemic for tick-borne encephalitis virus (TBEV), with the Central European subtype, also known as TBEV-EU (Figure 1). In all, 96 counties (i.e., 71.5% of all administrative districts) are considered to be risk areas for tick-borne encephalitis (TBE). The most intensive natural foci have been found in the western part of the country (Brest and Grodno Area), and infections in these areas account for an average of 40% each of the total number of reported cases


Author(s):  
Song Joon Young

Although no human case of tick-borne encephalitis (TBE) has been documented in South Korea to date,5 surveillance studies have been conducted to evaluate the prevalence of tick-borne encephalitis virus (TBEV) in wild ticks.1-5 Four studies collected ticks by dragging or flagging in grassland and forest, while 1 study tested wild mammals (boars and rodents) by removing ticks from them. In the wild of South Korea, Haemaphysalis spp. were the predominant species found by tick dragging, while Ixodes nipponensis became predominant when harvested from small mammals.6


Viruses ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 462 ◽  
Author(s):  
Mathias Boelke ◽  
Malena Bestehorn ◽  
Birgit Marchwald ◽  
Mareike Kubinski ◽  
Katrin Liebig ◽  
...  

Tick-borne encephalitis (TBE) is the most important tick-borne arboviral disease in Europe. Presently, the main endemic regions in Germany are located in the southern half of the country. Although recently, sporadic human TBE cases were reported outside of these known endemic regions. The detection and characterization of invading TBE virus (TBEV) strains will considerably facilitate the surveillance and assessment of this important disease. In 2018, ticks were collected by flagging in several locations of the German federal state of Lower Saxony where TBEV-infections in humans (diagnosed clinical TBE disease or detection of TBEV antibodies) were reported previously. Ticks were pooled according to their developmental stage and tested for TBEV-RNA by RT-qPCR. Five of 730 (0.68%) pools from Ixodes spp. ticks collected in the areas of “Rauher Busch” and “Barsinghausen/Mooshuette” were found positive for TBEV-RNA. Phylogenetic analysis of the whole genomes and E gene sequences revealed a close relationship between the two TBEV isolates, which cluster with a TBEV strain from Poland isolated in 1971. This study provides first data on the phylogeny of TBEV in the German federal state of Lower Saxony, outside of the known TBE endemic areas of Germany. Our results support the hypothesis of an east-west invasion of TBEV strains in Western Europe.


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