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. 2022 Jul;27(29):2200548.
doi: 10.2807/1560-7917.ES.2022.27.29.2200548.

Early start of seasonal transmission and co-circulation of West Nile virus lineage 2 and a newly introduced lineage 1 strain, northern Italy, June 2022

Luisa Barzon  1   2 , Fabrizio Montarsi  3 , Erika Quaranta  3 , Isabella Monne  3 , Monia Pacenti  2 , Alice Michelutti  3 , Federica Toniolo  3 , Patrizia Danesi  3 , Giulio Marchetti  3 , Federica Gobbo  3 , Alessandro Sinigaglia  1 , Silvia Riccetti  1 , Emanuela Dal Molin  1 , Laura Favero  4 , Francesca Russo  4 , Gioia Capelli  3
Affiliations

Early start of seasonal transmission and co-circulation of West Nile virus lineage 2 and a newly introduced lineage 1 strain, northern Italy, June 2022

Luisa Barzon et al. Euro Surveill. 2022 Jul.

Abstract

In spring 2022, Europe faced an unprecedented heatwave, increasing the risk of West Nile virus (WNV) outbreaks. As early as 7 June 2022, WNV was detected in Culex mosquitoes in northern Italy, and - in the following days - in two blood donors, a patient with encephalitis, wild birds and additional mosquito pools. Genome sequencing demonstrated co-circulation of WNV lineage 2 and a newly introduced WNV lineage 1, which was discovered in the region in 2021.

Keywords: One Health; West Nile virus; climate change; genome sequencing; lineage; surveillance.

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Conflict of interest statement

Conflict of interest: None declared.

Figures

Figure 1
Figure 1
Sites of West Nile virus lineage 1 infections in humans, birds and mosquitoes, Veneto region, Italy, 2021–2022 (n = 14)
Figure 2
Figure 2
Phylogenetic tree of West Nile Virus lineage 2 strains, Veneto region, Italy, 2021–2022 (n = 3 sequences)
Figure 3
Figure 3
Phylogenetic analysis of West Nile Virus lineage 1 strains, Veneto region, Italy, 2021–2022 (n = 9 sequences)
See this image and copyright information in PMC

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References

    1. Italian Ministry of Health. Piano Nazionale di prevenzione, sorveglianza e risposta alle Arbovirosi (PNA) 2020-2025. [National plan for prevention, surveillance and response to vector-borne viral diseases]. Rome: Italian Ministry of Health; 2019. Italian. Available from: https://www.salute.gov.it/imgs/C_17_pubblicazioni_2947_allegato.pdf
    1. Ravagnan S, Montarsi F, Cazzin S, Porcellato E, Russo F, Palei M, et al. First report outside Eastern Europe of West Nile virus lineage 2 related to the Volgograd 2007 strain, northeastern Italy, 2014. Parasit Vectors. 2015;8(1):418. 10.1186/s13071-015-1031-y - DOI - PMC - PubMed
    1. Pacenti M, Sinigaglia A, Franchin E, Pagni S, Lavezzo E, Montarsi F, et al. Human West Nile virus lineage 2 infection: epidemiological, clinical, and virological findings. Viruses. 2020;12(4):458. 10.3390/v12040458 - DOI - PMC - PubMed
    1. Barzon L, Pacenti M, Franchin E, Lavezzo E, Masi G, Squarzon L, et al. Whole genome sequencing and phylogenetic analysis of West Nile virus lineage 1 and lineage 2 from human cases of infection, Italy, August 2013. Euro Surveill. 2013;18(38):20591. 10.2807/1560-7917.ES2013.18.38.20591 - DOI - PubMed
    1. May FJ, Davis CT, Tesh RB, Barrett AD. Phylogeography of West Nile virus: from the cradle of evolution in Africa to Eurasia, Australia, and the Americas. J Virol. 2011;85(6):2964-74. 10.1128/JVI.01963-10 - DOI - PMC - PubMed