Meet the Expert

“An important message for veterinarians and farmers is that the spread of ASF from farm to farm is possible with a very small dose of the virus”

Professor Grzegorz Wozniakowski is Head of the Department of Swine Diseases at the National Veterinary Research Institute in Puławy, Poland, and also Director of Poland’s National Reference Laboratory on African swine fever. In addition to sharing his expertise on the diagnostic methods available for ASF, he describes a Polish study published in 2020 which demonstrated a delay of up to five days after infection before the appearance of clinical signs and found that even an extremely low titre of the viral strain tested was enough to infect pigs.

Running time: 34 minutes

“Highly pathogenic African swine fever virus is present in all wild boar in Poland; there are no safe levels of wild boar density”

Poland’s first incidence of ASF was in wild boar in 2014 and since then it has recorded over 7,000 wild-boar cases of the disease as well as nearly 270 outbreaks in domestic pigs, notes Professor Grzegorz Wozniakowski, Director of the country’s National Reference Laboratory on African swine fever. He sets out Polish experiences over the past six years in dealing with the risk of very virulent strains of the ASF virus passing to farm pigs from forest swine.

Running time: 33 minutes

“It is feasible to do it in a year, but we are going to be busy!”

In 2020, Boehringer Ingelheim has sponsored its latest annual European PRRS Research Awards which offer 25,000 Euros towards the funding of each of three research projects that are potentially of practical benefit in controlling PRRS. Hear the winners of the 2020 Awards describe the research they propose, given the time limit of completing the work in one year. A practitioner-led project in Denmark is to examine the impact of piglet weaning strategies on PRRSv in the nursery. An international team led from The Netherlands will use whole-genome sequencing to investigate genetic recombination in type-1 PRRS viruses. And, a study in Spain aims to measure how biosecurity measures against PRRS relate to the physical performance and profitability of commercial swine farms.

Running time: 30 minutes

“We know that vaccinating can decrease the amount of viruses in the air, so vaccination is a good mechanism to prevent airborne transmission”

Swine veterinary consultant Dr. Carmen Alonso in Spain picks out lessons from her detailed studies of air samples inside and outside farms suffering an outbreak of PRRS, influenza A or porcine epidemic diarrhoea --- as well as poultry sites with highly pathogenic avian influenza. Particle size in the air influenced the distance of transmission and also the amount of virus distributed. While larger particles travelled less far than small ones initially, they could be transported a longer total distance after settling on a vehicle that had been parked near the swine barn.

Running time: 30 minutes

“A weak spot for PRRS control comes when you take boar semen or gilts from outside into a herd”

Better surveillance for PRRS at boar stations in Denmark has followed a breakdown at a PRRS-negative boar station which led to sharply reduced sow productivity at herds in the area, reports Professor Lars Erik Larsen of the University of Copenhagen. Investigators discovered that the break involved a recombinant form of the virus, combining strains from two vaccines used at a sow herd about 5 kilometres from the boar station.

“Even people not feeling sick may be spreading the virus, so measures such as dividing teams of workers both physically and temporally are important to prevent transmission on the farm”

Food animal veterinarians can consider themselves as population medicine experts and therefore well qualified to advise swine farms on the extra precautions necessary both outside and inside the farm gate to prevent the entry of novel coronavirus SARS CoV2 and its spread among workers, we are told by independent swine veterinary consultant Dr. Carmen Alonso in Spain. She recommends using visual aids to pass the message to producers and their employees. A video showing an example can be found online at https://www.youtube.com/watch?v=Bo4IaL4X0qo, or using a browser search with the key words: biosecurity pig333.

Running time: 33 minutes

“Piglets as well as sows play a key role in transmitting the virus”

Veterinary virologist Dr. Pia Ryt-Hansen from the University of Copenhagen suggests practical lessons for controlling Porcine Respiratory Disease Complex viruses, based on her research into swine Influenza A virus or IAV-S in a sow herd in Denmark. Hear how production strategies and even maternally derived antibodies can actually contribute to viral persistence in the herd, plus potential benefits from the application of diagnostic tools such as genomic sequencing of virus identity and monitoring of coughing by pigs in the barn.

“People coming into the herd should at least have a vaccination against influenza”

Influenza A virus (IAV-S) can occur constantly within a swine herd, all year round, warns Dr. Pia Ryt-Hansen in Denmark. This persistence provides an ideal environment for the virus to change. A particular risk would arise if visitors or farm staff introduced seasonal strains of human influenza virus.

“Immunevasion and recombination are not linked, but both are part of the same complex allowing some PRRS viruses to evade the normal controls on the farm”

How can PRRS sometimes manage to penetrate apparently well protected farms? Viral mutation and the relatively slow completion of the pig’s immune response offer clues, according to this conversation with Dr. Enric Mateu, Professor of Animal Health at Universitat Autonoma de Barcelona in Spain and researcher at the CRESA Catalan institute of animal health.

Running time: 37 minutes

“There are indications that some of the oldest vaccine strains are not providing full protection against emerging new genotypes of parvovirus”

Hear how Dr. Poul Henning Rathkjen (Boehringer Ingelheim Nordic) and Professor Hans Nauwynck (Head of Virology at the University of Ghent’s veterinary medicine faculty in Belgium) assess recent reports of the emergence of new, virulent strains of the porcine parvovirus PPV.

Running time: 35 minutes