Efficient Transmission of Tick-Borne Encephalitis Virus Between Cofeeding Ticks

Лабуда, М; Jones, Linda D.; Williams, Trevor; Danielová, V.; Nuttall, Patricia A.

doi:10.1093/jmedent/30.1.295

Cited by 199 publications

(142 citation statements)

References 4 publications

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“…TBEV causes tick-borne encephalitis (TBE) in humans after the bite of an infected tick. Two different types of host are needed for the survival of TBEV: (i) ticks, which act as virus reservoirs and vectors, and (ii) vertebrate hosts, which act as a source of blood for feeding ticks and support TBEV transmission by co-feeding of infected and non-infected ticks on the same host (Labuda et al, 1993). Two tick species, the pasture tick (Ixodes ricinus L.) and the taiga tick (Ixodes persulcatus Schulze), are the main vectors of TBEV.…”

Section: Introductionmentioning

confidence: 99%

Origin and distribution of tick-borne encephalitis virus strains of the Siberian subtype in the Middle Urals, the north-west of Russia and the Baltic countries

Kovalev¹,

Chernykh²,

Kokorev

et al. 2009

Journal of General Virology

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Tick-borne encephalitis virus (TBEV) plays an important role in infectious human morbidity, particularly in Russia and the Middle Urals. The Siberian subtype of TBEV (S-TBEV) is dominant in the Middle Urals. Determining the origin of S-TBEV strains in this territory and also in the European part of Russia and the Baltic countries is very important for understanding the cause of its distribution. The surface glycoprotein E gene was partially sequenced in 165 S-TBEV isolates collected in the Middle Urals between 1966 and 2008. Nucleotide and amino acid sequence identity of the studied isolates is 94 and 97.4 %, respectively. Eighty per cent of them are represented by six clusters with identical amino acid sequences in the glycoprotein E fragment analysed. We have determined four types of isolate distribution in the explored territory: local, split, corridor and diffuse. The average rate of nucleotide substitutions per site year "1 is estimated to be 1.56¾10 "4 . The age of the S-TBEV population was evaluated to be slightly less than 400 years. Phylogenetic analysis of the data and comparison with historical events indicate that the distribution of S-TBEV strains in the Middle Urals and the European part of Russia originated twice from different foci in western Siberia. This is related to the first land road into Siberia and the Trans-Siberian Way, which functioned at different times. The main reason for such rapid distribution of S-TBEV strains is the anthropogenic factor, i.e. human economic activity during the colonization of new territories in Siberia in the recent past.

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Section: Introductionmentioning

confidence: 99%

Origin and distribution of tick-borne encephalitis virus strains of the Siberian subtype in the Middle Urals, the north-west of Russia and the Baltic countries

Kovalev¹,

Chernykh²,

Kokorev

et al. 2009

Journal of General Virology

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“…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.…”

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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“…Because susceptible, insusceptible, and immune hosts can support NVT (6)(7)(8), the population of vertebrates that may contribute to the WNV transmission cycle is probably much greater than was previously realized. Furthermore, with no requirement for a latent incubation period in the vertebrate, because virus can be directly transmitted from one mosquito to another, the transmission process is accelerated.…”

Section: Resultsmentioning

confidence: 99%

“…The discovery of NVT challenged the paradigm that arboviruses are transmitted only by arthropods feeding on viremic hosts. NVT was first observed with ticks cofeeding on rodents (6)(7)(8)(9), which was subsequently demonstrated by Mead et al (10) for vesicular stomatitis virus (VSV) between cofeeding black flies, but has not previously been reported for mosquitoes. Our hypothesis for this study was that the quantity of WNV secreted in the saliva of infected mosquitoes is sufficiently high to infect adjacent cofeeding mosquitoes directly without the requirement for replication in the vertebrate host.…”

Section: T He Unexpected Introduction Of West Nile Virus (Wnv) Intomentioning

confidence: 95%

Nonviremic transmission of West Nile virus

Higgs

Schneider

Vanlandingham

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

109

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West Nile virus (WNV) is now the predominant circulating arthropod-borne virus in the United States with >15,000 human cases and >600 fatalities since 1999. Conventionally, mosquitoes become infected when feeding on viremic birds and subsequently transmit the virus to susceptible hosts. Here, we demonstrate nonviremic transmission of WNV between cofeeding mosquitoes. Donor, Culex pipiens quinquefasciatus mosquitoes infected with WNV were fed simultaneously with uninfected ''recipient'' mosquitoes on naïve mice. At all times, donor and recipient mosquitoes were housed in separate sealed containers, precluding the possibility of mixing. Recipients became infected in all five trials, with infection rates as high as 5.8% and no detectable viremia in the hosts. Remarkably, a 2.3% infection rate was observed when 87 uninfected mosquitoes fed adjacent to a single infected mosquito. This phenomenon could potentially enhance virus survival, transmission, and dispersion and obviate the requirement for viremia. All vertebrates, including immune and insusceptible animals, might therefore facilitate mosquito infection. Our findings question the status of dead-end hosts in the WNV transmission cycle and may partly explain the success with which WNV established and rapidly dispersed throughout North America.Culex ͉ mosquito vector

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Efficient Transmission of Tick-Borne Encephalitis Virus Between Cofeeding Ticks

Cited by 199 publications

References 4 publications

Origin and distribution of tick-borne encephalitis virus strains of the Siberian subtype in the Middle Urals, the north-west of Russia and the Baltic countries

Origin and distribution of tick-borne encephalitis virus strains of the Siberian subtype in the Middle Urals, the north-west of Russia and the Baltic countries

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

Nonviremic transmission of West Nile virus

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