Expert panel: We still have a lot to learn about ASF
At the recent Animal Health Investment Europe forum in London, Animal Pharm editor Joseph Harvey chaired a panel discussion on African swine fever (ASF). Below is a summary of the highlights, including insight into vaccine development and the impact coronavirus might have on the Chinese pork market.
ASF is here to stay and there remains a lot to be learned about this lethal threat. This was the consensus of the panel that gave an overview of the disease from political, trade and R&D point-of-views.With a vaccine up to five years away from commercialization, the panelists agreed enhanced biosecurity is critical to preventing the spread of ASF.
Justin Sherrard – global strategist animal protein at Rabobank – said: "We've got the opportunity to be much better at biosecurity in situations like this. I think technology has the potential to play an enormous role here in monitoring animal health, for example – early detection of what is going on. We haven't really seen that used to its full advantage for ASF. My impression is the whole supply chain is yet to embrace the opportunity that technology provides.
"At the same time, we have a challenge with technology. How do we get the whole of the supply chain – down to the end consumer – comfortable with the way we're using technology? What's the consumer going to make of all of this? It's a little bit of a double-edged sword.
"Overall, biosecurity is really important. You would think: 'Do we need to be reminded of that?' But apparently, we do. You've seen the way the disease has spread. It's incredible and it's still spreading. There's been a new outbreak in Greece – it's significant because it's part of Europe and has access to very good information about the risks and how to manage them. You would assume effective control measures are in place everywhere in Europe."
Linda Dixon – group leader of the ASF virus group at the Pirbright Institute – remarked: "One thing we've learned during this epidemic is the important role wild boar have played in the spread of disease. Particularly in eastern and northern Europe, wild boar have been the main source of infection. Spillover from wild boar to domestic pigs has been the main route outbreaks have occurred. That was something that was entirely unpredicted before this epidemic.
"We've learned to reduce the population density of wild boar and we've learned more about how to control outbreaks in wild boar. Perhaps this has not been fully investigated in Asia."
Dr Dixon said a lack of investment from commercial entities has stymied development of a viable ASF vaccine in the past. However, she was positive a vaccine could be developed in the next five years.
Linda Dixon: "The technology for scaling up the vaccine production within the industry still needs to be developed. There also needs to be experiments to complete the regulatory process. So, there are still some question marks and time is required to take those promising candidates through to the marketplace."
"There are already some very promising candidates at the experimental stage," she told delegates. "The technology for scaling up the vaccine production within the industry still needs to be developed. There also needs to be experiments to complete the regulatory process. So, there are still some question marks and time is required to take those promising candidates through to the marketplace."
Dr Dixon suggested a vaccine could come along earlier than five years, with China investing a lot of money in R&D. Recently, the country's Harbin Veterinary Research Institute claimed to have developed a potential gene-deleted ASF vaccine.
A live attenuated vaccine produced using gene deletion will be the most likely preventative solution developed against ASF, Dr Dixon suggested. She called for more investment to be made in developing vaccines that can be applied by different routes of administration. This would ensure there is a variety of options in the pipeline should any specific type of vaccine fail to show great efficacy or safety.
Dr Dixon said the biggest gap in ASF prevention is the knowledge required to scale-up a live attenuated vaccine. She pointed out high containment facilities needed to produce and test a vaccine are in short supply globally.
Antivirals are another area of innovation that could boost control measures, according to Dr Dixon. Last year, Belgian start-up ViroVet said it is working with Pirbright on antivirals for ASF that could receive rapid emergency authorization.
Dr Dixon added: "We don't understand a lot about the virus and how a live attenuated vaccine might behave in the field. Previously, in Spain, there was a live attenuated vaccine introduced in the 1960s that actually caused quite a serious chronic disease. So, that was quickly withdrawn from the market. It's really important any candidate vaccines go through a full safety testing protocol."
She also suggested a virus vectored vaccine has long-term promise in protecting pigs against ASF. However, a lot of work still needs to be carried out to pinpoint the proteins that can be produced at commercial scale for this type of vaccine.
Pirbright recently worked with University College London to map when ASF genes are expressed during infection, identifying new genes in the process.
Governments have key role to play
Laurie Hueneke, MSD Animal Health associate vice president of global public policy and government relations, said governments have an important role to play in fostering innovation that will help in the prevention, control and eventual eradication of ASF outbreaks.
The role of governments is to enable private and public partnerships that will generate scientific knowledge and necessary measures and tools that will help countries better respond to this disease.
Ms Hueneke pointed out governments need to create an environment that allows innovators to invest in ASF, while establishing zones and compartments for the trade of protein products. She said each country has a responsibility to ensure their infrastructure is in place to allow research collaborators and laboratories to carry out important research on the ASF virus.
She said: "Many countries still need to raise awareness and undertake action in the measures relating to the improvement of biosecurity, but reaching an optimal level generally requires a combination of prevention and control activities implemented through local initiatives with government support. We need to have a conversation about biosecurity with all of these countries."
Mitigating factors to recovery
Mr Sherrard said global pork production was down by just over 10% in 2019 due to the ramifications of ASF. Total meat production fell by approximately 3.5%.
He noted: "Maybe that doesn't sound like a lot but if you look back over 20, 30 or 50 years, you will not find a single year where we have seen a larger decline than 2019. It is truly unprecedented.
"Although we saw pork production down by a record amount, our view is this year we will still see ongoing declines in global pork production. That will be close to 8-10%. With other proteins doing a little more production, you'll end up seeing total global protein production down by about 1.5% this year."
Mr Sherrard also pointed out three complications that will influence China's recovery from ASF:
Coronavirus, which he said has already had an impact on consumption in China and is going to have an impact on production and trade as well;
The US/China trade war; and
The role of the Chinese authorities in pricing – the government manages a state reserve of frozen pork inventory, which will influence domestic restocking, trade volumes and global production response.
He commented: "While we don't have an effective solution to the situation, we will see this rolling on for another couple of years."