137 | Bluetongue and epizootic hemorrhagic disease in wildlife with particular attention to the Sicilian scenario

Francesca Gucciardi¹, Valeria Blanda¹, Paola Galluzzo¹, Sergio Migliore¹, Federico Cangialosi¹, Davide Pepe¹, Valeria Vaglica¹, Antonina Princiotta¹, Santina Di Bella¹, Josephine Muscarella¹, Jessica Pivotti¹, Antonia Raia¹, Ettore Napoli², Annalisa Guercio¹, Giuseppa Purpari¹ | ¹Istituto Zooprofilattico Sperimentale della Sicilia “A. Mirri”, Palermo, Italy; ²Dipartimento di Scienze Veterinarie, Università degli Studi di Messina, Italy.

Bluetongue (BT) and Epizootich Emorrhagic Disease (EHD) are two vector-borne infectious diseases that are clinically very similar. They are transmitted by insects of the genus Culicoides spp. and are caused by two RNA viruses belonging to the genus Orbivirus: the Bluetongue virus (BTV) and the epizootich emorrhagic disease virus (EHDV). These pathogens mainly affect domestic ruminants but can also infect wild ruminants, which may contribute to the spread and persistence of the infections. Although they are not zoonoses, BT and EHD have a significant impact from a sanitary, environmental, and economic perspective, representing a major risk to animal health and international trade. Infections manifest with a wide spectrum of clinical signs and lesions, which vary depending on the affected species and the viral strain. BTV and EHDV show a marked affinity for the erythrocyte membrane, a characteristic that allows them to persist for long periods in the host, actingas reservoirs with important epidemiological implications. Climate change, the increase in wild ungulate density, and the growing interaction between domestic and wildlife animals make it necessary to further investigate the transmission mechanisms and routes of spread of BTV and EHDV in order to implement early detection and control strategies. Due to its geographical position, Sicily is particularly exposed to the introduction of arboviruses from North Africa, representing one of the main gateways to the European continent. In Sicily, the main wild ruminant species is the fallow deer, present mainly in the Madonie Park (Palermo) and the Peloritani Mountains (Messina). Following the identification in 2024 of a case of BTV-8 in a fallow deer from the province of Messina, confirmed by the National Reference Centre for Exotic Animal Diseases at IZS Abruzzo and Molise, surveillance activities for BTV and EHDV were intensified during 2024–2025 in wildlife. Targeted sampling of fallow deer, wascarried out, oftenwithincullingcampaigns, in areas of the province of Messina and in the Madonie Park. Overall, 165 organ samples including lung, trachea, spleen, and lymphnodes, were collected from 65 fallow deer. Samples underwent RNA extraction and amplification by specific real-time RT-PCR for BTV and EHDV [2]. None of the analyzed samples tested positive for BTV or EHDV, suggesting that fallow deer did not represent the main reservoir of the two orbiviruses in Sicily during the period considered. These results contributed to expanding epidemiological knowledge on the circulation of BTV and EHDV in wildlife in relation to the environmental and territorial characteristics of the island, improving the understanding of virus maintenance cycles and the complex interactions among pathogens, hosts, and vectors in ecosystems with high biodiversity.

This work was funded by the project GR-2021-12373930 and the project RC IZS SI 02/23.