An Arbovirus Cline across the Northern Hemisphere

Zanotto, Paolo Marinho de Andrade; Gao, Guozhen; Грицун, Т.С.; Marín, Margarita; Jiang, Wei-Wei; Venugopal, K.; Reid, H.W.; Gould, E. A.

doi:10.1006/viro.1995.1326

Cited by 131 publications

(105 citation statements)

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“…The mosaic character of the distribution of FE-TBEV isolates in non-FE-TBEV-endemic territories is not in agreement with the hypothesis of continuous evolution of TBEV and its persistent expansion into new geographical regions (Zanotto et al, 1995). It is very unlikely that the parallel and similar evolution of TBEVs occurred in restricted geographical areas, and we suggest that FE-TBEV foci appeared in the non-endemic regions relatively recently.…”

contrasting

confidence: 88%

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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contrasting

confidence: 88%

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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“…The difference among the tick-borne viruses grouping together is quite high suggesting a long evolutionary history in the slow evolutionary process described for viruses in ticks [20,28]. It is of note that UUKV and SFSTV are more closely related to each other than to either BHAV or PALV (Fig.…”

Section: Discussionmentioning

confidence: 87%

Genetic characterization of Bhanja virus and Palma virus, two tick-borne phleboviruses

et al. 2012

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“…The results obtained by the molecular clock analysis suggested that SLEV is a relatively new flavivirus in comparison with other flaviviruses that are transmitted by mosquitoes, such as dengue virus and yellow fever virus (Zanotto et al, 1995(Zanotto et al, , 1996Bryant et al, 2007), as its evolutionary history was dated between 1875 and 1973 (mean 1898). The analysis conducted by Auguste et al (2009), which included 73 SLEV strains, indicated SLEV dispersal from South America towards North America and is in agreement with the current chronological analysis of the 133 SLEVs performed in this study (Fig.…”

Section: Resultsmentioning

confidence: 99%

Molecular epidemiology of Saint Louis encephalitis virus in the Brazilian Amazon: genetic divergence and dispersal

Rodrigues

Nunes

Casseb

et al. 2010

Journal of General Virology

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Saint Louis encephalitis virus (SLEV), a member of the genus Flavivirus (family Flaviviridae), is an encephalitogenic arbovirus broadly distributed in the Americas. Phylogenetic analysis based on the full-length E gene sequences obtained for 30 Brazilian SLEV strains was performed using different methods including Bayesian and relaxed molecular clock approaches. A new genetic lineage was suggested, hereafter named genotype VIII, which co-circulates with the previously described genotype V in the Brazilian Amazon region. Genotypes II and III were restricted to Sã o Paulo state (South-east Atlantic rainforest ecosystem). The analysis also suggested the emergence of an SLEV common ancestor between 1875 and 1973 (mean of 107 years ago), giving rise to two major genetic groups: genotype II, more prevalent in the North America, and a second group comprising the other genotypes (I and III-VIII), broadly dispersed throughout the Americas, suggesting that SLEV initially emerged in South America and spread to North America.In conclusion, the current study demonstrates the high genetic variability of SLEV and its geographical dispersion in Brazil and other New World countries. INTRODUCTIONSaint Louis encephalitis virus (SLEV) is an encephalitogenic arbovirus with a primary life cycle associated with Culex mosquitoes and wild birds (Travassos da Rosa et al., 1997; Vasconcelos et al., 1998;Reisen, 2003). Taxonomically, Saint Louis encephalitis virus is a recognized species of the genus Flavivirus, family Flaviviridae, and belongs to the Japanese encephalitis virus (JEV) group, which includes other important human pathogens such as West Nile virus (WNV), JEV and Murray Valley encephalitis virus (Calisher & Gould, 2003).SLEV is widely distributed throughout the western hemisphere from Canada to Argentina. SLEV was first isolated in 1933 during a major epidemic that occurred in St Louis, Missouri, USA, with more than 1000 encephalitis cases reported. Outbreaks or clusters of encephalitis cases associated with SLEV have been reported annually in the USA (Reisen, 2003). Usually, the fatality rate ranges from 5 to 20 % (Tsai & Mitchell, 1988), with higher mortality rates observed among the elderly (.75 years of age) (Reisen, 2003).The low number of human cases reported in tropical regions of the Americas may reflect inadequate laboratory diagnosis, circulation of less virulent virus strains and/or enzootic cycles involving mosquitoes that are not typically anthropophilic (Spense, 1980). Only three SLEV strains have been isolated from humans in Brazil. Two patients resident in Para state had clinical manifestations characterized by fever and jaundice (Pinheiro et al., 1981; Vasconcelos et al., 1998), whilst one from São Paulo was suspected of dengue-like disease (Rocco et al., 2005). None of them had neurological symptoms. Recently, the SLEV genome was detected by RT-PCR in four patients with clinical symptoms similar to those observed in dengue fever, as well as in two other patients clinically diagnosed as presenting with viral...

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An Arbovirus Cline across the Northern Hemisphere

Cited by 131 publications

References 0 publications

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

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

Genetic characterization of Bhanja virus and Palma virus, two tick-borne phleboviruses

Molecular epidemiology of Saint Louis encephalitis virus in the Brazilian Amazon: genetic divergence and dispersal

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