Sequence analyses of PCR-positive samples from north-western and eastern Germany reveal the presence of a further variant related to the Shamonda virus, alongside the ‘Shamonda virus/DE/2026’ variant, which has been circulating primarily in southern Germany, Switzerland and France since July. The cattle samples originate from North Rhine-Westphalia, Lower Saxony, Hesse and Thuringia. This virus belongs to the species Orthobunyavirus Schmallenbergense of the Simbu serogroup and is related to the Shamonda virus originally identified in Africa and Japan. However, it differs significantly from the Shamonda virus/DE/2026 variant initially detected in Switzerland, France, and southern Germany. To facilitate distinction, the two variants are now designated Shamonda virus Europe 1 (SHAV-EU1) and Shamonda virus Europe 2 (SHAV-EU2) respectively.
The current outbreak therefore comprises two independent events which are already overlapping in some federal states. More detailed phylogenetic analyses are currently being carried out to better characterise the second variant. Initial investigations show that all three genome segments of SHAV-EU2 differ from those of SHAV-EU1. Further research is required to determine whether sufficient cross-protection exists between the two variants following infection.
The exact host range of the new variant is as yet unknown. To date, all positive samples for SHAV-EU2 have come from cattle. Infections with Shamonda virus Europe 1 have so far been detected in cattle, horses, sheep, and goats.
Three orthobunyaviruses of the Simbu serogroup are currently circulating in Germany: Schmallenberg virus and the two Shamonda virus variants. It is therefore likely that these viruses will exchange genome segments and mutate (reassort).
