Equine Screening for West Nile Virus in Mecklenburg-Western Pomerania

Significantly increasing detections of West Nile virus (WNV) in Germany (DE) since 2018 demonstrate the need for intensified surveillance as well as research on pathogen circulation in the federal states as well as in Europe, not least against the background of zoonotic potential. In Mecklenburg-Vorpommern (M-V), a systematic screening of dead equids was established in 2020/21 with the aim of an epidemiological evaluation of spatial and temporal WNV detection data. A total of 1010 blood samples were screened for flavivirus-specific antibodies (AK) by IgG ELISA and 16 reactants were identified. All IgG reactants were negative by IgM ELISA. In one of these 16 samples WNV-AK was detected by neutralization test at the National Reference Laboratory of the FLI / Riems (NRL). Further differential diagnosis of possible Usutu virus and TBEV-AK reactions at the NRL revealed TBEV-positive AK reactions in the neutralization test in five animals. The findings suggest that WNV circulation in the country's equine population of approximately 27,500 animals is currently negligible.