Epizootic hemorrhagic disease of ruminants: current knowledge (review)

Abstract

Introduction . Epizootic hemorrhagic disease (EHD) is a vector-borne, infectious, non-contagious disease affecting wild and domestic ruminants, characterized by congestive and hemorrhagic manifestations. The causative agent is a virus of the genus Orbivirus family Sedoreoviridae, which is transmitted between susceptible animals through the bites of Culicoides midges. Over the past 20 years, epizootic hemorrhagic disease virus (EHDV) has spread to new regions. Since 2022, large scale outbreaks among cattle have been reported in Southern Europe, posing a serious threat to the livestock industry. Objective . To summarize and analyze current published data on the global situation regarding EHD. Materials and methods . Analytical research methods were employed using the following databases: PubMed, Willey Online Library, MDPI, Google Scholar, eLibrary, and CyberLeninka. Results . A brief description of the disease’s causative agent is provided. To date, seven serotypes of EHDV have been identified worldwide, with a novel serotype 10 recently reported. A global geographical spread of EHDV across all continents is observed, with regional variations in serotype distribution. Serotypes 1, 2, 6, 7, 8, and 10 exhibit increased pathogenicity, causing EHD outbreaks in deer and cattle. This review briefly discusses the factors contributing to the spread of EHDV to new territories. It also describes clinical signs of EHD in susceptible animals, outlines key prevention and control measures to reduce the risk of new outbreaks, and identifies current research gaps. Conclusion . The ability of EHDV to undergo recombination, the emergence of highly virulent strains, and the progressive expansion of vector ranges may lead to large-scale outbreaks with significant economic losses in the livestock sector, including European and Asian countries. In current conditions, it is necessary to enhance entomological and virological surveillance for the early detection and control of EHDV spread among ruminants.