Deletion Mutants of Schmallenberg Virus Are Avirulent and Protect from Virus Challenge

Abstract

SBV induces only mild clinical signs in adult ruminants but causes severe fetal malformation and, thereby, can have an important impact on animal welfare and production. As SBV is an insect-transmitted pathogen, vaccination will be one of the most important aspects of disease control. Here, mutant viruses lacking one or two proteins that essentially contribute to viral pathogenicity were tested as modified live vaccines in cattle. It could be demonstrated that a novel recombinant double deletion mutant is a safe and efficacious vaccine candidate. This is the first description of a putative modified live vaccine for the complete genus Orthobunyavirus, and in addition, such a vaccine type has never been tested in cattle for any virus of the entire family Bunyaviridae. Therefore, the described vaccine also represents the first model for a broad range of related viruses and is of high importance to the field.