October 23, 2023

Scientists in China develop new ASF vaccine candidate




A new vaccine candidate has been developed by Chinese scientists to combat African swine fever (ASF).


The virus has devastated the pork industry globally in recent years, according to Weng Changjiang, co-author of the research detailing the potential vaccine.


"It has resulted in economic losses of hundreds of billions of yuan for the swine industry, affecting the livelihoods of many people and industry development," he told the South China Morning Post on October 17.


For the vaccine candidate, Weng's team designed a live but weakened version of the virus to trigger a strong immune reaction. To do this, the scientists deleted two highly pathogenic genes previously identified in the ASF virus to create a new mutant. This was then administered to two groups of five pigs – grouped as low-dose and high-dose. All the animals developed detectable antibodies.


After 28 days, the pigs were then given the virus.


Results showed that all vaccinated pigs survived the illness. A few animals in the low-dose group exhibited mild, brief clinical symptoms with the virus detectable in their blood, but no significant tissue lesions were found.


Meanwhile, a control group of pigs which were not given the vaccine died within 10 to 12 days of contracting the virus.


The vaccine research was conducted by a group of scientists from Harbin Veterinary Research Institute, under the Chinese Academy of Agricultural Sciences, with the findings published last month in the peer-reviewed Journal of Virology.


"We addressed some unclear issues in basic research by extensively screening more than 180 genes of this (ASF) virus," Weng said, noting that his team has identified a crucial structural protein, one of the two pathogenic genes mentioned earlier.


The knowledge equates to a big leap in the field. It allows the vaccinated pigs to avoid infecting other animals they come into contact with, and prevents more pigs from being culled.


Weng added that the vaccine candidate did not show any adverse reactions, such as prolonged fever, after being administered. It is also a simple immunisation protocol, requiring just a single dose.


However, Weng said, there is still a long way to go before the vaccine becomes commercially viable, with technical, regulatory and financial hurdles to jump.

- South China Morning Post

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