Occurrence of malformed calves in April - May 2021 indicates an
unnoticed 2020 emergence of Schmallenberg virus in Denmark
Abstract
During the European emergence of Schmallenberg virus (SBV) in 2011,
examination of Culicoides spp. showed that SBV infected midges
were present across Denmark. However, SBV associated malformations in
ruminant species have not been reported in Denmark. In April 2021, seven
calves with severe congenital generalized arthrogryposis and reduced
body weight originating from a narrow region of the Jutlandic peninsula
were submitted for examination. Analysis of fetal brain tissue for SBV
viral RNA and pleural effusion for fetal anti-SBV antibodies identified
SBV as the cause of the congenital syndrome. Backwards calculation from
the calving dates indicated the occurrence of an unnoticed emergence of
SBV in Denmark from early August 2020 and during the late summer and
autumn. As SBV associated malformations may lead to dystocia urging for
fetotomy or Cesarean section, veterinarians performing obstetric
intervention are first line personnel in recognition of SBV emergence in
domestic ruminants.