Natural Tick-Borne Encephalitis Virus Infection among Wild Small Mammals in the Southeastern Part of Western Siberia, Russia

Бахвалова, В. Н.; Dobrotvorsky, Andrey K.; Panov, V. V.; Матвеева, В. А.; Tkachev, Sergey; Морозова, О. В.

doi:10.1089/vbz.2006.6.32

Cited by 43 publications

(49 citation statements)

References 19 publications

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“…The analysis of only 333 sera from rodents captured in 2006 Ð2007 allowed us to detect the presence of anti-TBEV antibodies at three out of four (Thun, Belp, Kiesen, but not at Trimstein) sites in Switzerland whereas in a previous study, the screening of 9,986 ticks by RT-PCR (Thun: n ϭ 2,001; Belp: n ϭ 2,117; Kiesen: n ϭ 4,230; (Burri et al 2011). A small proportion of rodents displayed anti-TBEV antibodies, ranging from 1.6 to 9.9%, but these results are consistent with results from Kozuch et al (1967) and Bakhvalova et al (2006) who reported antibody prevalence of 4 Ð11% and 2.6 Ð10.2%, respectively. Interestingly, although more rodents were captured in 2007, seroprevalence in rodent was lower than in 2006.…”

Section: Discussionsupporting

confidence: 89%

Serological Evidence of Tick-Borne Encephalitis Virus Infection in Rodents Captured at Four Sites in Switzerland

et al. 2012

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In a previous study, the presence of tick-borne encephalitis virus (TBEV) in questing Ixodes ricinus L. ticks and in Þeld derived ticks that engorged on small mammals (n ϭ 9,986) was investigated at four sites located in a TBE area in Switzerland. Two of these sites were already recognized as TBE foci (Thun and Belp) and the screening of ticks revealed the presence of TBEV in ticks at a third site, Kiesen, but not at the fourth one, Trimstein. The aim here was to test another approach to detect TBE endemic areas. Sera from 333 small mammals (Apodemus flavicollis, A. sylvaticus, Myodes glareolus) captured in 2006 and 2007 at the four sites were examined for the presence of antibodies against TBEV using immunoßuorescence and avidity tests. Overall the prevalence of antibodies against TBEV in rodents reached 3.6% (12/333). At two sites known as TBE foci, Thun and Belp, anti-TBEV antibodies were detected in 9.9% (9/91) and 1.6% (1/63) of rodent sera, respectively. At the third site, Kiesen, recently identiÞed as a TBE focus by the detection of TBEV in ticks, anti-TBEV antibodies were detected in 1.8% (2/113) of rodent sera. Finally, at Trimstein, none of the examined rodent sera had antibodies against TBEV (0/66). This study shows another approach to detect TBE foci by testing antibodies in small mammal sera that is less time-consuming and less expensive than molecular tools.

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Section: Discussionsupporting

confidence: 89%

Serological Evidence of Tick-Borne Encephalitis Virus Infection in Rodents Captured at Four Sites in Switzerland

et al. 2012

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“…Therefore, Germany seems to be a country of low TBE risk in comparison to a prevalence of 61% in rodents of a high endemic area in Siberia (Bakhvalova et al 2006). This rating is supported by the low incidence of human TBE cases in Germany compared with other European countries, for example, the Czech Republic or Russia (Donoso Mantke et al 2008).…”

Section: Discussionmentioning

confidence: 98%

“…They are widespread in most ecological systems, have a small home range, are easy to trap and monitor, and are heavily parasitized by ticks, which probably results in higher TBE virus prevalence (and thus lower associated costs) than in ticks. Once infected with TBEV, they are supposed to develop a persistent infection , Nuttall et al 1994, Danielova et al 2002, Sü ss 2003, Bakhvalova et al 2006, Gray et al 2009, Kiffner et al 2011.…”

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confidence: 99%

Rodents as Sentinels for the Prevalence of Tick-Borne Encephalitis Virus

Achazi

Růžek

Donoso-Mantke

et al. 2011

Vector-Borne and Zoonotic Diseases

110

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Introduction: Tick-borne encephalitis virus (TBEV) causes one of the most important flavivirus infections of the central nervous system, affecting humans in Europe and Asia. It is mainly transmitted by the bite of an infected tick and circulates among them and their vertebrate hosts. Until now, TBE risk analysis in Germany has been based on the incidence of human cases. Because of an increasing vaccination rate, this approach might be misleading, especially in regions of low virus circulation. Method: To test the suitability of rodents as a surrogate marker for virus spread, laboratory-bred Microtus arvalis voles were experimentally infected with TBEV and analyzed over a period of 100 days by real-time (RT)-quantitative polymerase chain reaction. Further, the prevalence of TBEV in rodents trapped in Brandenburg, a rural federal state in northeastern Germany with autochthonous TBE cases, was determined and compared with that in rodents from German TBE risk areas as well as TBE nonrisk areas. Results: In experimentally infected M. arvalis voles, TBEV was detectable in different organs for at least 3 months and in blood for 1 month. Ten percent of all rodents investigated were positive for TBEV. However, in TBE risk areas, the infection rate was higher compared with that of areas with only single human cases or of nonrisk areas. TBEV was detected in six rodent species: Apodemus agrarius, Apodemus flavicollis, Apodemus sylvaticus, Microtus agrestis, Microtus arvalis, and Myodes glareolus. M. glareolus showed a high infection rate in all areas investigated. Discussion and Conclusion: The infection experiments proved that TBEV can be reliably detected in infected M. arvalis voles. These voles developed a persistent TBE infection without clinical symptoms. Further, the study showed that rodents, especially M. glareolus, are promising sentinels particularly in areas of low TBEV circulation.

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“…Probably, the number of FE-TBEV strains present was too small to form a stable viral population and there was competition from endemic S-TBEV strains. Evidence for the long-term persistence of TBEV in populations of small rodents without ticks was provided by the vertical transmission of TBEV between generations of these animals (Bakhvalova et al, 2006(Bakhvalova et al, , 2009. Comparable data are missing for large mammals and birds.…”

mentioning

confidence: 99%

Distribution of Far-Eastern tick-borne encephalitis virus subtype strains in the former Soviet Union

Kovalev

Kokorev

Belyaeva

2010

Journal of General Virology

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European and Asian viruses within the tick-borne encephalitis flavivirus complex are known to show temporal, spatial and phylogenetic relationships that imply a clinal pattern of evolution. However, the isolation of recognized Far-Eastern tick-borne encephalitis virus (TBEV) strains in the European region of the former Soviet Union (SU), i.e. thousands of kilometres west of the region in which they are considered endemic, appears to contradict this concept. Here, we present a parsimonious explanation for this apparent anomaly based on analysis of the dates and regions in which these non-endemic strains were isolated, together with their phylogenetic relationships and the records of redistribution of animals under the All-Union programme for acclimatization of game animals within the former SU. Our evidence supports the concept that the anomalous distribution of Far-Eastern TBEV strains in Europe and Siberia arose primarily as the result of the large-scale westward redistribution of game animals for economic purposes.Tick-borne encephalitis virus (TBEV), belonging to the tickborne flavivirus group, genus Flavivirus, family Flaviviridae, is a prototype representative of the seroviruses group of the same name, which were discovered in 1937 in the Russian Far East. TBEV is the causative agent of tick-borne encephalitis in humans, usually after the bite of an infected tick. Two types of host are required for TBEV circulation in nature. The first is the tick as the reservoir and carrier of TBEV and the second the vertebrate animal whose blood is the nutrient source for ticks and also the way in which the virus is transmitted from infected to non-infected ticks by their feeding on the same animal (Labuda et al., 1993). Ixodes ricinus L. and Ixodes persulcatus Schulze are the two main TBEV vectors. Small mammals are the principal hosts for pre-imaginal ticks, whereas mature ticks feed on large mammals such as lagomorphs, predators, hoofed animals and birds (Pavlovsky, 1947;Filippova, 1985). All these animals are natural reservoirs of TBEV in the infection hot spots.According to phylogenetic analysis, there are three TBEV subtypes: Far-Eastern (FE-TBEV) and Siberian (S-TBEV), which are both transmitted by I. persulcatus, and European (Eu-TBEV), which is transmitted by I. ricinus. Each TBEV subtype has specific nucleotide substitutions in the protein E gene and their classification is based on this characteristic (Ecker et al., 1999). Strains belonging to the different TBEV subtypes have their own geographical distributions. Specifically, Eu-TBEV is endemic in Europe and includes strains collected in Austria, Switzerland, Germany, Sweden, Hungary, the Czech Republic, Slovenia, Finland, Latvia, Lithuania, Estonia, Byelorussia (Belarus) and the European part of Russia (Ecker et al., 1999;Lundkvist et al., 2001;Haglund et al., 2003), FE-TBEV is distributed mainly in the Russian Far East, the eastern part of North China and northern Japan. S-TBEV is commonest in eastern and western Siberia, in the Ural region, the European pa...

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Natural Tick-Borne Encephalitis Virus Infection among Wild Small Mammals in the Southeastern Part of Western Siberia, Russia

Cited by 43 publications

References 19 publications

Serological Evidence of Tick-Borne Encephalitis Virus Infection in Rodents Captured at Four Sites in Switzerland

Serological Evidence of Tick-Borne Encephalitis Virus Infection in Rodents Captured at Four Sites in Switzerland

Rodents as Sentinels for the Prevalence of Tick-Borne Encephalitis Virus

Distribution of Far-Eastern tick-borne encephalitis virus subtype strains in the former Soviet Union

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