West Nile Virus Lineage 2 Spreads Westwards in Europe and Overwinters in North-Eastern Spain (2017–2020)

Aguilera‐Sepúlveda, Pilar; Napp, Sebastián; Llorente, Francisco Rubio; Solano-Manrique, Carlos; Molina-López, Rafael; Obón, Elena; Solé, Alba; Jiménez‐Clavero, Miguel Ángel; Fernández-Piñero, Jovita; Busquets, Núria

doi:10.3390/v14030569

Cited by 21 publications

(26 citation statements)

References 44 publications

(96 reference statements)

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“…WNV lineages 1 and 2 have also been molecularly confirmed in different animal species in this country in the last decade. Lineage 1 is the most widely distributed and is responsible for outbreaks in humans, horses and birds in Spain (García‐Bocanegra et al., 2018; Casimiro‐Soriguer et al., 2021); to date, lineage 2 has only been found in mosquitoes and wild birds (Busquets, Alba, Allepuz, Aranda, & Núñez, 2008; Aguilera‐Sepúlveda et al., 2022). The first clinical case of WNV in horses was reported in summer 2010 and was associated with lineage 1.…”

Section: Introductionmentioning

confidence: 99%

High exposure of West Nile virus in equid and wild bird populations in Spain following the epidemic outbreak in 2020

García‐Bocanegra

Franco

León

et al. 2022

Transbounding Emerging Dis

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A cross‐sectional study was conducted to assess the circulation and risk factors associated with West Nile virus (WNV) exposure in equine and wild bird populations following the largest epidemic outbreak ever reported in Spain. A total of 305 equids and 171 wild birds were sampled between November 2020 and June 2021. IgG antibodies against flaviviruses were detected by blocking enzyme‐linked immunosorbent assay (bELISA) in 44.9% (109/243) and 87.1% (54/62) of unvaccinated and vaccinated equids, respectively. The individual seroprevalence in unvaccinated individuals (calculated on animals seropositive by both bELISA and virus microneutralization test [VNT]) was 38.3% (95%CI: 33.1–43.4). No IgM antibodies were detected in animals tested (0/243; 0.0%; 95%CI: 0.0–1.5) by capture‐ELISA. The main risk factors associated with WNV exposure in equids were age (adult and geriatric), breed (crossbred) and the absence of a disinsection programme on the facilities. In wild birds, IgG antibodies against flaviviruses were found in 32.7% (56/171; 95%CI: 26.8–38.6) using bELISA, giving an individual WNV seroprevalence of 19.3% (95%CI: 14.3–24.3) after VNT. Seropositivity was found in 37.8% of the 37 species analysed. Species group (raptors), age (>1‐year old) and size (large) were the main risk factors related to WNV seropositivity in wild birds. Our results indicate high exposure and widespread distribution of WNV in equid and wild bird populations in Spain after the epidemic outbreak in 2020. The present study highlights the need to continue and improve active surveillance programmes for the detection of WNV in Spain, particularly in those areas at greatest risk of virus circulation.

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Section: Introductionmentioning

confidence: 99%

High exposure of West Nile virus in equid and wild bird populations in Spain following the epidemic outbreak in 2020

García‐Bocanegra

Franco

León

et al. 2022

Transbounding Emerging Dis

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“…For instance, the geographic range of WNV cases designated to the Lombardy cluster, which consisted of WNV cases from Lombardy, Italy, as of 2015 (Barzon et al 2015), is recently expanding. The Lombardy cluster now also includes WNV sequences from France and Spain (Aguilera-Sepulveda et al 2022). Similarly, WNV clade 2d sequences from the European continent were designated according to the supposed region of the viruses’ origins, like WNV sequences from Russia and Romania that were designated as the Eastern European lineage 2 WNV (EE, Figure 3) (Cotar et al 2018; Ravagnan et al 2015) or WNV sequences from Hungary, Austria, Greece, Serbia, and Italy that were put into the Central/Southern European lineage 2 WNV (C/SE, Figure 3) (Chaintoutis et al 2019; Ziegler et al 2020).…”

Section: Resultsmentioning

confidence: 99%

Section: Proposal For a Hierarchical Wnv Nomenclature Below The Speci...mentioning

confidence: 99%

An advanced sequence clustering and designation workflow reveals the enzootic maintenance of a dominant West Nile virus subclade in Germany

Santos

Günther

Keller

et al. 2022

Preprint

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West Nile virus (WNV) is the most widespread arthropod-borne (arbo) virus and the primary cause of arboviral encephalitis globally. Members of WNV species genetically diverged and are classified into different hierarchical groups below species rank. However, the demarcation criteria for allocating WNV sequences into these groups remain individual, inconsistent, and the use of names for different levels of the hierarchical levels is unstructured. In order to have an objective and comprehensible grouping of WNV sequences, we developed an advanced grouping workflow using the ″affinity propagation clustering″-algorithm and newly included the ″agglomerative hierarchical clustering″-algorithm for the allocation of WNV sequences into different groups below species rank. In addition, we propose to use a fixed set of terms for the hierarchical naming of WNV below species level and a clear decimal numbering system to label the determined groups. For validation, we applied the refined workflow to WNV sequences that have been previously grouped into various lineages, clades, and clusters in other studies. Although our workflow regrouped some WNV sequences, overall, it generally corresponds with previous groupings. We employed our novel approach to the sequences from the WNV circulation in Germany 2020, primarily from WNV-infected birds and horses. Besides two newly defined minor (sub)clusters comprising only of three sequences each, subcluster 2.5.3.4.3c was the predominant WNV sequence group detected in Germany from 2018-20. This predominant subcluster was also associated with at least five human WNV-infections in 2019-20. In summary, our analyses imply that the genetic diversity of the WNV population in Germany is shaped by enzootic maintenance of the dominant WNV subcluster accompanied by sporadic incursions of other rare clusters and subclusters. Moreover, we show that our refined approach for sequence grouping yields meaningful results. Although we primarily aimed at a more detailed WNV classification, the presented workflow can also be applied to the objective genotyping of other virus species.

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“…17 ,20,122 Ancillary diagnostic tests such as complete blood count (CBC), biochemical analysis and cerebrospinal fluid (CSF) analysis could T A B L E 1 Spread of Lineage 2 WNV (WNV-L2) across Europe. WNV-L2 is divided in 2 clades, the Central Southern European (CSE) clade and the Romanian/Russian (R/R) clade 87 CSF analysis is often nonspecific and variable with elevated nucleated cell count (mononuclear or neutrophilic pleocytosis) and/or protein concentration and mild xanthochromia. 123,124 The antemortem detection of WNV in blood and/or CSF via culture and qPCR is rarely achieved because of the short-lived and low-level viremia reported in equids.…”

Section: Geographical Distributionmentioning

confidence: 99%

European College of Equine Internal Medicine consensus statement on equine flaviviridae infections in Europe

Cavalleri

Korbacska-Kutasi

Leblond

et al. 2022

Veterinary Internal Medicne

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Horses and other equids can be infected with several viruses of the family Flaviviridae, belonging to the genus Flavivirus and Hepacivirus. This consensus statement focuses on viruses with known occurrence in Europe, with the objective to summarize the current literature and formulate clinically relevant evidence‐based recommendations regarding clinical disease, diagnosis, treatment, and prevention. The viruses circulating in Europe include West Nile virus, tick‐borne encephalitis virus, Usutu virus, Louping ill virus and the equine hepacivirus. West Nile virus and Usutu virus are mosquito‐borne, while tick‐borne encephalitis virus and Louping ill virus are tick‐borne. The natural route of transmission for equine hepacivirus remains speculative. West Nile virus and tick‐borne encephalitis virus can induce encephalitis in infected horses. In the British Isle, rare equine cases of encephalitis associated with Louping ill virus are reported. In contrast, equine hepacivirus infections are associated with mild acute hepatitis and possibly chronic hepatitis. Diagnosis of flavivirus infections is made primarily by serology, although cross‐reactivity occurs. Virus neutralization testing is considered the gold standard to differentiate between flavivirus infections in horses. Hepacivirus infection is detected by serum or liver RT‐PCR. No direct antiviral treatment against flavi‐ or hepacivirus infections in horses is currently available and thus, treatment is supportive. Three vaccines against West Nile virus are licensed in the European Union. Geographic expansion of flaviviruses pathogenic for equids should always be considered a realistic threat, and it would be beneficial if their detection was included in surveillance programs.

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West Nile Virus Lineage 2 Spreads Westwards in Europe and Overwinters in North-Eastern Spain (2017–2020)

Cited by 21 publications

References 44 publications

High exposure of West Nile virus in equid and wild bird populations in Spain following the epidemic outbreak in 2020

High exposure of West Nile virus in equid and wild bird populations in Spain following the epidemic outbreak in 2020

An advanced sequence clustering and designation workflow reveals the enzootic maintenance of a dominant West Nile virus subclade in Germany

European College of Equine Internal Medicine consensus statement on equine flaviviridae infections in Europe

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