April 20 marks World Animal Vaccination Day, raising awareness about the important of vaccines
By Melanie Epp
April 20th marks the fourth annual World Animal Vaccination Day, an event meant to raise awareness about the vital role vaccines play in protecting the health of animals. With half of the world’s pork supply under the threat of African Swine Fever (ASF) there is no better time to raise awareness about the importance of vaccines in livestock production.
ASF’s impact on pork producers in Europe, and particularly China, has been devastating. A recent report by Rabobank estimates that outbreaks in China have decreased the local pork supply by 25-35 per cent. The organization does not believe that it’s possible to replace the missing pork supply with other protein products, nor do they believe that the missing supply can be imported. They say it could take years for China’s pork sector to recover.
Quicker recovery could be possible if a vaccine were available. Currently, however, the disease has no known treatment. Around the world, public and private sector researchers are working on solutions.
Jishu Shi, Director of the US-China Center for Animal Health at the College of Veterinary Medicine at Kansas State University, for example, has developed a multi-plex PCR to detect whether pigs have classical swine fever or African swine fever. The PCR has been made public and can be used in any lab.
“People can design their own PCR based on our information,” he said.
Shi is also working on a vaccine for ASF, but his work is in the very early stages.
In the UK, Linda Dixon, Head of the African Swine Fever Virus Group at the Pirbright Institute, is also working on a vaccine. ASF is caused by a very complex DNA virus, she said, which makes ASF its own virus family, unrelated to other viruses.
“The virus codes for about 170 proteins and has 70 or more in the virus particle,” she said. “Due to this complexity some methods used to produce vaccines for other smaller viruses, like FMDV or Bluetongue virus, haven’t worked for ASF.”
“Inactivation of the ASF virus particle to produce a vaccine hasn’t worked for ASF,” she said.
The vaccines that will most likely be successful, she said, will be live-attenuated vaccines, which are weakened viruses that don’t cause disease but induce an immune response that protects them.
Researchers at the Pirbright Institute have now obtained several good candidates for live-attenuated vaccine strains and are in the process of fine-tuning the genes deleted to produce a vaccine strain that is safe. It could be years before a vaccine is available.