Eurosurv. Outbreak of autochthonous West Nile virus infection in Lazio region, Italy, July to August 2025: preliminary investigation

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• Ilaria Mussetto^1,* , Andrea Bongiovanni^1,* , Francesca Colavita¹ , Cristina Giambi² , Marcello Giovanni Sala³ , Cosmo Del Borgo⁴ , Fabrizio Carletti¹ , Maria Teresa Scicluna³ , Alessandro Zerbetto² , Angela Corpolongo¹ , Federico Romiti³ , Maria Beatrice Valli¹ , Stefania Vaglio⁵ , Roberto Giammattei⁶ , Paola Scognamiglio^1,7 , Gabriella De Carli¹ , Alessandro Agresta¹ , Claudio De Liberato³ , Giuseppe Di Luzio⁸ , Florindo Micarelli² , Emanuele Nicastri¹ , Andrea Siddu⁷ , Valeria Ficarelli⁷ , Enrico Girardi¹ , Fabrizio Maggi¹ , Francesco Vairo¹ , the Lazio WNV Outbreak Group⁹

In July–18 August 2025, 171 autochthonous cases with West Nile virus (WNV) infection were confirmed in Lazio, Italy: four asymptomatic blood donors, 110 with WNV fever, 57 with neuroinvasive syndrome and nine deaths. WNV lineage 2 was detected in two neuroinvasive cases. Infection with WNV was confirmed in 28 horses, five crows and a Culex pipiens pool. We present the preliminary epidemiological and phylogenetic analysis of the outbreak and the public health measures taken within a One Health approach.

https://www.eurosurveillance.org/content/10.2807/1560-7917.ES.2025.30.35.2500634#html_fulltext