What is Schmallenberg virus?
Schmallenberg virus (SBV) is a member of the orthobunyavirus genus of the family Bunyaviridae. It gets its name from the town in Germany where samples were taken from when the virus was identified in 2011.
The virus only appears to infect ruminants. In adult cows, it causes fever, diarrhoea and reduced milk production. In pregnant sheep, cows and goats, depending on the stage of gestation, it causes stillbirths and birth defects.
Although in a different family, Schmallenberg is similar to bluetongue virus in that it’s transmitted by biting midges (Culicoides). It’s thought to have been accidentally transported from Africa to Europe, where it spread rapidly. It probably then came to the UK by prevailing winds blowing infected midges across the English Channel.
Although the virus appeared to die down after a peak in 2013, it re-emerged in 2016 and it looks likely that there will be regular epidemics as older livestock are replaced with young stock that have no natural immunity.
Our research and its impact
Our research on SBV initially focused on understanding how the virus has spread in the UK since its emergence and the impact this has had on farmers. We’ve also been working with companies to develop cheaper and more rapid tests that can detect antibodies and help farmers make informed decisions about whether to vaccinate their flocks and herds.
In addition, we’ve been using next-generation phage display technology to identify peptide epitopes on the virus that are specifically recognised by antibodies from animals infected with the virus, but not by antibodies generated by vaccination with a killed virus vaccine.
This type of ‘differentiating infected from vaccinated animals’ (DIVA) test could be hugely valuable during outbreaks of emerging viruses, when movement and export restrictions may be placed on infected animals that don’t need to be applied to vaccinated animals. These projects have been funded by the British Biological Research Council and Innovate UK.
Another avenue of research is determining how the virus crosses the ruminant placenta to cause fetal deformities.