Der Podcast von und für Schweineprofis

“The antibodies generated by some old vaccine strains have their neutralising capability reduced by the new PPV”

Professor André Felipe Streck of the University of Caxias do Sul in Brazil gives his expert view of the key question: Are long-established PPV vaccines still effective when faced with new field strains of the virus? He also discusses whether years of vaccinating sow herds against reproductive failure due to the porcine parvovirus PPV have played any part in the mutation of the virus into newer forms. (Running time: 20 minutes)

“We have an evolutionary process with this virus… evolutionary hot-spots on the surface of the virus, located at points in contact with the host’s immune system”

In southern Brazil, Professor André Felipe Streck of the Institute of Biotechnology at the University of Caxias do Sul leads us through the changing story of the porcine parvovirus PPV. Long considered a stable virus that could be controlled by vaccines developed four decades ago, its evolution into diverse forms has become evident since the year 2000. Newer strains display amino acid substitutions in the capsid or external protein layer of the virus which influence antigenicity. (Running time: 33 minutes)

“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

“Vaccinating animals decreases clinical signs and also the amount of viruses in the air, so it is a good mechanism to reduce airborne transmission”

While taking her doctorate in veterinary population medicine at the University of Minnesota, Dr. Carmen Alonso investigated the extent to which swine viruses were transmitted in the air from a farm suffering an outbreak. In this conversation she describes the influence of particle size on the airborne transmission of the viruses of PRRS, Influenza A and the porcine epidemic diarrhoea syndrome --- and explains how even large particles with a high viral load can be carried a long distance. (Running time: 34 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. (Running time: 28 minutes)

“Extra biosecurity should begin outside the farm…our graphics for training emphasise not only the risks from contacts within the farm, but also from those that workers have on their way to work and from their families.”

We talk to international veterinary consultant and population medicine expert Dr. Carmen Alonso about her recommendations for the precautions that a swine farm should take, to shield its farm workers from the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) infection responsible for Covid-19 disease in humans during the worldwide pandemic. Dr. Alonso reports good results from using visual aids to convey key messages to the people who work on the farm. (Running time: 32 minutes)

“During winter time, the African swine fever virus may persist up to five months in the bone marrow of a wild boar's carcass”

A significant reduction in Europe’s wild boar populations and good biosecurity on all swine farms are necessary steps to combat African swine fever, Professor Zygmunt Pejsak emphasises in this Meet The Expert podcast. Professor Pejsak was head of the swine diseases department at the National Veterinary Institute in Poland when ASF first entered the country across its Eastern border. He discusses strategic options against the disease and makes the case for having effective surveillance in any affected or potentially affected country to control the possible introduction of a novel virus genotype.

“The direction of wild boar movement in general is to the Western territories...it means from Russia to Belarus, from Belarus to Poland, from Poland to Germany and probably will be from Germany to France”

As the Head of the Department of Swine Diseases at the National Veterinary Research Institute until his retirement, Professor Zigmunt Pejsak in Poland played a central role in the country's battle against African swine fever. In conversation with journalist Peter Best, he discusses how the ASF virus has travelled from East to West in European wild boar populations and the possibilities for its further spread.

“We plan a quarantine time of a minimum eight weeks and if we use MLV PRRS virus vaccines, we prefer around 12 weeks”

Gilt introduction procedures are discussed by Danish swine veterinarian Dr. Kristian Havn in the context of a herd averaging 1,000 sows with an annual replacement rate of 45-50%, meaning a need to bring in 500 replacement gilts per year. A target of introduction to the sow herd at 34 weeks old dictates that gilts must be no older than 22 weeks on arrival, to accommodate a 12-weeks quarantine period. How to expose them to herd pathogens is still an open question, he says, because we will want them to produce an adequate level of antibodies in their colostrum when they eventually enter the farrowing room.

“Gilts can be the best reproductive performers on the farm in terms of conception rates and farrowing rates --- if they are not the best, there’s an opportunity there for us to go work on”

For larger sow systems, a group-based gilt preparation process from weaning at 6 kilograms to breeding at 135 kg is detailed in this conversation in the United States with Dr. Clayton Johnson, veterinarian partner and Director of Health at Carthage Veterinary Services. Health acclimation should begin as early as possible, he tells us. Ideally therefore, bring prospective herd replacement gilts into an isolation barn when they are weaned. Groups would consist of four weeks’ worth of gilts, with the animals tagged to identify their birth week. Isolation is followed by time in a developer barn, until gilts weighing at least 120 kg when showing first oestrus are judged ready to move to the gestation area.

“It’s important that pathogen exposure occurs early enough in the gilt’s life so she recovers from the infection, stops shedding the pathogen and is immunocompetent at the time of farrowing”

Divide the young gilt’s time before breeding into the separate categories of development and acclimation, says Dr. Clayton Johnson of Carthage Veterinary Services in the U.S.A. Development aims to prepare her physiology for a future in reproduction, acclimation tries to arm her immune system to cope with the pathogens in the sow herd. Target at least 680 grams of gain per day in the gilt developer phase. How acclimation is handled needs to be specific to each pathogen and each herd.

“It is a totally new challenge for the feed industry --- a number of feed components can be quite a good environment for the virus, which can stay infectious for a longer time”

In our final conversation about ASF with Dr. Tomasz Trela, technical manager for swine at Boehringer Ingelheim's regional centre covering Central and Eastern Europe, he emphasises the evidence connecting ASF infection to feed sources. These could be green crops harvested from contaminated fields, but also the virus has been detected in feed-mills in some countries and delivery vehicles may need to be diverted around hot-spots where infected wild boar are found.

“ASF virus is very resistant to physical and chemical factors, this means it can stay infective for weeks or even months”

The resistance of the virus and the difficulties of decontamination are just two of the issues facing swine farms that are located in an area where the infection is known to be present, says Dr. Tomasz Trela, Boehringer Ingelheim's technical manager for swine in Central and Eastern Europe. Quite new for swine veterinarians is the situation where wild boar represent a huge reservoir of pathogens surrounding the farms. All potential carriers of the virus onto a farm must be considered.

“We have re-introductions of diseases in some of our farms every year, so something must be able to improve biosecurity...our plan is to evaluate all 1,220 farms that we consult”

Dr. Kristian Havn is a swine veterinary practitioner with the Porcus practice in Denmark who has pioneered an innovative programme to improve biosecurity on the swine farms that he advises. In English, the programme’s name translates at Pathogen Stop. Its basis is an online survey form completed by the veterinarian in consultation with the farmer. The original idea was to make a system for evaluating biosecurity at farm level regarding PRRS virus, Dr. Havn explains in this podcast. But it has been extended to cover all pathogens, including APP, swine influenza, mycoplasma and even African swine fever.

“Biosecurity is the only tool we have now to protect our pigs against ASF”

Precautions for protecting the farm against the entry of the African swine fever virus are explained by Dr. Tomasz Trela, the Boehringer Ingelheim technical manager for swine in Central and Eastern Europe. Based on the experiences of swine farms in Europe and Asia, he warns of the ways in which that the virus can be carried in, such as on vehicles and feed. More conversations with Dr. Trela about ASF feature in other Meet The Expert podcasts.

“African swine fever is a very slow disease...we have the experience during outbreaks that not all pigs become infected”

Dr. Tomasz Trela, the technical manager for swine in Central and Eastern Europe at Boehringer Ingelheim's regional centre in Vienna, shares his personal observations of European and Asian sow farms suffering an outbreak of African swine fever. This first episode covers on-farm lessons regarding the recognition and diagnosis of the disease; in a further Meet The Expert podcast he discusses implications for biosecurity at farm level.

“Sow farms that were virus positive when we started the programme are doing a lot better now...also, we have less airway disease in the growers and finisher pigs regarding problems that are secondary to PRRS”

Hear from Danish swine veterinarian Dr. Kristian Havn how 40 farms in an area of western Denmark have been taking part in an area PRRS control programme over the past two years. Dr. Havn devised the programme after attending a training course where details were presented of area-level eradication of PRRS virus on a smaller scale in Iowa. One lesson had been the value of encouraging the area’s swine farm operators to work together as a team. The farms in Denmark occupied a pig-dense part of the country with a history of PRRS problems and they varied in size up to 1,450 sows. To update everyone on progress, large maps were created on which colour coding showed when a farm was finally cleared of the virus.

“When you go over 14 live births and the sow has 12-14 functional teats, you need split-suckling protocols”

Sow herds should consider split-suckling (also called shift- suckling) if litters contain more than 14 liveborn pigs in order to improve survival rates, according to Drs. Rutger Jansen, technical service manager for swine at Boehringer Ingelheim in The Netherlands and a specialist on colostrum management. Lower mortality and more marketable pigs will pay for the 5-10 minutes of extra work time per litter involved in split- suckling. Dr. Jansen discusses details of the technique and also occasions when baby pigs may need training to drink from a teat or even bottle-feeding with colostrum milked from their mother or from another sow in the herd.

“The basic input for the pig that is needed is an intake of 250 grams of colostrum, then the survival chances are more or less equal for all the pigs”

Bigger litters from modern prolific sows increase the challenge of making sure that every newborn pig consumes enough colostrum, we hear from Drs. Rutger Jansen. He's field technical service manager in The Netherlands for the Boehringer Ingelheim swine health portfolio and takes a special interest in colostrum management in sow herds. The first indicator of whether colostrum is being managed correctly is the herd's rate of pre-weaning deaths, he says, since over 75% of mortality in the first days of life relates to insufficient intake. Colostrum production from a typical sow may not meet the needs of more than 15-16 newborn pigs and competition in big litters creates uneven distribution because the larger piglets drink more than their share.

“Our recent work demonstrated the presence of the PCV-3 genome within mild-to moderate histological lesions of aborted fetuses. This supports that PCV-3 should be considered as a potential causative pathogen for reproductive failure"

Professor Segalés shares his recent experience investigating the relevance of PCV3, posing the question: What is the clinical and economic impact of this emerging virus in sows and growing piglets? During this conversation we will hear the latests information that will help you understand the current state of knowledge.

“So far, all vaccines in the market have shown great efficacy in reducing clinical signs associated to diseases caused by PCV-2, independently of the genotype present in the farm. Moreover, experimental data demonstrated the cross-protection of PCV-2a vaccines against the most widespread genotypes (PCV-2a, PCV-2b, and PCV-2d). Therefore, despite the significant number of genotypes described/proposed (PCV-2a to PCV-2i), it seems one single PCV-2 serotype would exist".

Joaquim Segalés is full professor at the UAB and researcher at the IRTA-CReSA animal health research institute. He has been working with swine diseases for the last 28 years and he has also been working with zoonotic coronaviruses since 2014. He is co-author of more than 350 peer-reviewed publications, most of them on pig diseases and specifically on porcine circovirus diseases. Professor Segalés will share his wealth of experience on the evolution of the PCV2 virus and what that means in terms of diagnosis, understanding the evolving epidemiology and the control using vaccines. How can we make the right decisions on the farm?

“African swine fever and classical swine fever are two completely different diseases in their epidemiology and the behaviour of the virus”

How does the African swine fever virus reach and infect domestic pigs? The most common routes are spelled out in this podcast featuring Dr. Klaus Depner, a virologist and ASF specialist who leads a working group on transboundary animal disease management at FLI, the German federal institute for animal health. The virus does not enter on infected droplets or airborne transmission, he says, most often it has been carried into the barn by people. The main way it invades a pig's body is through contaminated feed or water, although even then only a small proportion of the animals exposed become infected.

“We learned that it's a human-made disease so it's a matter of what people are doing and how they behave”

Virologist Dr. Klaus Depner in Germany tells us that preventing the entry of the African swine fever virus is fundamentally a matter of good farm biosecurity coupled with education of the general public so they are not transmitting the virus or carrying it in food or other materials. At the German federal institute for animal health FLI, Dr. Depner heads a working group on transboundary animal disease management. Controlling ASF within territories demands a long view, he says. African swine fever is a disease where you need lots of patience.