West Nile and Usutu Viruses' Surveillance in Birds of the Province of Ferrara, Italy, from 2015 to 2019.

Alessandra Lauriano,Elena Carra,Giorgio Galletti,Gabriele Casadei,Mattia Calzolari,Davide Lelli,Silva Rubini,Annalisa Santi,Marco Tamba,Arianna Rossi

doi:10.3390/v13071367

Alessandra Lauriano, Elena Carra + Show 8 more

Open Access

https://doi.org/10.3390/v13071367

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Abstract

West Nile (WNV) and Usutu (USUV) viruses are mosquito-borne flaviviruses. Thanks to their importance as zoonotic diseases, a regional plan for surveillance of Arboviruses was implemented in Emilia-Romagna in 2009. The province of Ferrara belongs to the Emilia-Romagna region, and it is an endemic territory for these viruses, with favorable ecological conditions for abundance of mosquitoes and wild birds. From 2015 to 2019, we collected 1842 dead-found birds at a wildlife rehabilitation center, which were analysed by three different PCRs for the detection of WNV and USUV genomes. August was characterized by the highest infection rate for both viruses. Columbiformes scored the highest USUV prevalence (8%), while Galliformes and Strigiformes reported the highest prevalence for WNV (13%). Among Passeriformes (the most populated Order), Turdus merula was the most abundant species and scored the highest prevalence for both viruses. To optimize passive surveillance plans, monitoring should be focused on the summer and towards the avian species more prone to infection by both viruses.

Highlights

Usutu (USUV) and West Nile (WNV) viruses are neurotropic mosquito-borne flaviviruses, members of the Japanese encephalitis antigenic group
Among the sequences present in GenBank, the most similar ones, with a 100% identity, originated from mosquitoes (2010) (JF834599, JF834604, JF834606, JF834616, JF834623, JF834626, JF834673) and from one human case of neurological disease (2009) in Emilia-Romagna (JF826447). These findings confirm that the USUV strain circulating in the province of Ferrara belongs to the Europe 2 (EU2) clade, a clade detected in North Italy since 2009 [5]
Usutu and West Nile viruses are Flaviviruses maintained in the environment through an enzootic cycle involving mosquitoes and wild birds

Summary

Introduction

Usutu (USUV) and West Nile (WNV) viruses are neurotropic mosquito-borne flaviviruses, members of the Japanese encephalitis antigenic group. They were first discovered in Africa during the XX century, and they are considered endemic in several European countries. USUV and WNV have probably the same life cycles, including ornithophylic mosquitoes (mainly Culex spp.) as the main vectors and wild birds as amplifying hosts. Thanks to its geographical characteristics and the co-existence of mosquitoes, as well as stationary and migratory wild birds, this area is an optimal environment for epidemiological studies in order to optimize USUV and WNV surveillance programs [3,4,5]. We present the results of a 5-year passive surveillance program covering wild birds in this province

Survey Area

Sample Collection

Samples Analyses

Results

Discussion