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; Fabrizio Montarsi; Erika Quaranta; Isabella Monne; Monia Pacenti; Alice Michelutti; Federica Toniolo; Patrizia Danesi; Giulio Marchetti; Federica Gobbo; Alessandro Sinigaglia; Silvia Riccetti; Emanuela Dal Molin; Laura Favero; Francesca Russo; Gioia Capelli

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

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

Authors

Luisa Barzon^{1

2}, Fabrizio Montarsi³, Erika Quaranta³, Isabella Monne³, Monia Pacenti², Alice Michelutti³, Federica Toniolo³, Patrizia Danesi³, Giulio Marchetti³, Federica Gobbo³, Alessandro Sinigaglia¹, Silvia Riccetti¹, Emanuela Dal Molin¹, Laura Favero⁴, Francesca Russo⁴, Gioia Capelli³

Affiliations

¹ Department of Molecular Medicine, University of Padova, Padua, Italy.
² Microbiology and Virology Unit, Padova University Hospital, Padua, Italy.
³ Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro, Padua, Italy.
⁴ Direzione Prevenzione, Sicurezza Alimentare, Veterinaria, Regione del Veneto, Venice, Italy.

PMID: 35866436
PMCID: PMC9306260
DOI: 10.2807/1560-7917.ES.2022.27.29.2200548

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.

MeSH terms

Animals
Culex*
Culicidae*
Disease Outbreaks
Humans
Italy / epidemiology
Seasons
West Nile Fever* / diagnosis
West Nile Fever* / epidemiology
West Nile virus* / genetics