Schmallenberg virus (SBV), an orthobunyavirus (family Bunyaviridae) of the Simbu serogroup, was detected for the first time in late 2011 in Germany. The virus, which is transmitted by Culicoides biting midges, infects predominantly domestic and wild ruminants. Starting near the German-Dutch border the virus has spread extremely fast and caused a large epidemic in European livestock. Further members of the Simbu serogroup (e.g. Sathuperi, Shamonda, Aino, and Akabane viruses) are present in Australia, Asia, and Africa and cause a mild transient disease. Infected adult animals show none or only mild symptoms such as fever, a decrease in milk production, or diarrhea. The viraemic period lasts only a few days. However, an infection of naïve animals during a critical phase of pregnancy may induce severe congenital malformations, premature birth or stillbirth and reproductive disorders; an SBV-infection of pregnant sheep leads more often to the birth of malformed offspring than in cattle. An infection late in gestation may result in the birth of seropositive calves and lambs.
An infection with Schmallenberg virus is a reportable animal disease.