More than a decade of research on Schmallenberg virus-Knowns and unknowns

Schmallenberg virus, an arbovirus of the Orthobunyavirus genus that primarily infects ruminants, emerged in 2011 near the Dutch-German border region and subsequently caused a large number of abortions and the births of severely malformed newborns in the European livestock population. Immediate intensive research led to the development of reliable diagnostic tests, the identification of competent Culicoides vector species, and the elucidation of the pathogenesis in infected vertebrate hosts. In addition, the structure of the major antigenic domain has been elucidated in great detail, leading to the development of effective marker vaccine candidates. The knowledge gained over the last decade on the biology and pathogenesis of SBV and the experience acquired in its control will be of great value in the future for the control of any similar emerging pathogen of veterinary or public health importance such as Shuni or Oropouche virus. However, some important knowledge gaps remain, for example, the factors contributing to the highly variable transmission rate from dam to fetus or the viral factors responsible for the vector competence of Culicoides midges are largely unknown. Thus, questions still remain for the next decade of research on SBV and related viruses.