26 Nov 2018
Congress delegates at the BVD Zero Web Congress at the University of Glasgow School of Veterinary Science.
The author joined a gathering of vets, students and other interested parties to watch the Boehringer Ingelheim BVDZero Web Congress at the University of Glasgow School of Veterinary Science.
Achieving herd-level bovine viral diarrhoea (BVD) eradication is possible, but the BVD virus is constantly mutating, with strains appearing and disappearing, making complete eradication more challenging, head of SAC Consulting Veterinary Services George Caldow told viewers.
Along with Mr Caldow, the congress hosted world-leading speakers Julia Ridpath, from the National Animal Disease Center, US, and Dan Givens, from Auburn University, US, at simultaneous screenings around the world, including Europe and the US. A Q&A session followed three informative lectures.
BVD was first identified in 1946, with type two first reported in 1987, explained Dr Ridpath.
“BVD virus was originally thought to be part of just three related pestivirus species each in different hosts, with classical swine fever seen in pigs, BVD in cattle and border disease in sheep, but, based on genomic comparisons, new related viruses are now being recognised in other species – for example, giraffes,” she said.
She also explained the complications caused by other closely related species, pointing out a HoBi-like virus was detected in 2004 and is also part of the wider BVD family, posing yet another challenge to virus detection tests, and control and eradication plans.
Dr Ridpath went on to share how a ruminant’s age affects its susceptibility to infection and what this means for a neonate exposed to the BVD virus. The virulence and pathogenesis of a virus is affected by:
Dr Ridpath stressed more work needed to be done to fully understand the relationship between age at exposure and seroconversion, but it remains at the heart of the spread of the BVD virus.
Dr Givens discussed the many challenges for the cattle producer, which can result in reproductive loss. He described BVD among several other infectious causes of fetal loss.
On the topic of BVD eradication and whether vaccination should form a compulsory part of it, Mr Caldow stated: “Eradication is highly achievable when an appropriate plan is followed. For BVD control to be successful, it must first involve the detection and removal of persistently infected animals.
“There must then be a high level of biosecurity implemented and a vaccination plan put in place to protect naive animals within the herd.
“The simple facts are BVD is driven by two things: the presence of persistently infected animals and BVD virus naive animals.
“Control and eradication strategies rely on reducing the possibility of direct or indirect contact between these groups of animals.”
Mr Caldow added that, while diagnostic gaps could disrupt BVD control plans, vets and farmers shouldn’t be put off.
“Vaccinating breeding animals is central to control programmes, except where national eradication has been achieved, with spot testing of calves in the window between nine months old and before vaccination offering the best way to monitor the success of eradication,” he said.
