Multiplex serological screening of wild boar as sentinels of emerging zoonoses: HEV, WNV, and TBEV distribution in Saxony, Germany

Targeted wildlife surveillance enables early detection of emerging infections and facilitates prevention of wildlife-human spillover events. The Eurasian wild boar (<i>Sus scrofa</i>) serves as a valuable indicator species for wildlife surveillance due to its broad European distribution and its ability to adapt to diverse habitats. Wild boar and domestic pigs are the main reservoir for hepatitis E virus (HEV) genotype 3, which can be transmitted to humans mainly through consumption of undercooked meat. Wild boar can also be infected by vector-borne pathogens like the mosquito-transmitted orthoflavivirus West Nile virus (WNV), and the related tick-borne encephalitis virus (TBEV). To establish an efficient multi-pathogen serological screening system for wild boar surveillance, a multiplex bead-based serological assay was developed for the detection of antibodies against HEV, WNV, and TBEV. Screening of 960 wild boar sera collected in 2023/24 from eight districts in Saxony, Central/Eastern Germany, revealed moderate seropositivity for HEV (24.3 %) and TBEV (33.8 %), and low positivity for WNV (8.4 %). Molecular analysis identified HEV RNA in five individuals, and sequencing followed by phylogenetic analysis showed close relationship to subtype HEV-3i. These findings demonstrate that wild boar in Saxony are exposed to HEV, WNV, and TBEV, highlighting the value of multiplex serological screening as an effective tool for wildlife-based surveillance of these viruses.