A ONE HEALTH-APPROACH FOR WEST NILE AND USUTU VIRUS SURVEILLANCE IN AVIFAUNA IN PIEDMONT, NORTHWESTERN ITALY: 2021 DATA

Abstract

Intro: Vector-borne diseases are a major public health concern representing about 17% of the total cases of communicable diseases (WHO data). In Italy, West Nile (WNV) and Usutu (USUV) surveillance activities since 2020 are included in the National Plan for Prevention, Surveillance and Response to Arboviruses 2020-2025. The Plan integrates the surveillance measures to be implemented at the national level for autochthonous/imported arboviruses; a multidisciplinary approach in the management of surveillance/control activities is promoted. Here we report data on WNV and USUV circulation in 2021 in birds in Piedmont/Italy, northwestern region, an endemic area at high risk of transmission. Methods: Passive surveillance (PS) was carried out on wild birds found dead during the whole year. Active surveillance (AS) was performed on culled wild birds from target species (magpie, grey crow, jay) during the high risk season (from April to November): plans for abatement of resident avifauna are promoted to protect agricultural crops. For each bird sampled, central nervous system and a pool of organs (heart, spleen and kidney) were analysed. RNA was extracted using a commercial kit and tested by real-time RT-PCRs detecting WNV Lineage 1 and 2, and USUV. All positive samples were sent to the OIE National reference Centre in Teramo (IZSTe) for confirmation. Findings: From January 2021 to December 2021 a total of 1063 samples were analysed by real time RT-PCR, of which 301 from wild birds (PS) and 762 from target species (AS). Five subjects among wild species and 3 subjects from target species tested positive to RT-PCR for WNV lineage 2; none tested positive for USUV. Conclusion: Surveillance on WNV and USUV allowed to detect viral circulation in birds in Piedmont, Northwestern Italy, with the aim of reducing human risk of infection, mainly through a timely enforcement of blood donors screening and risk communication to public.