November 12, 2019


China study discovers possible key to developing African swine fever vaccine 


Chinese Centre for Disease Control and Prevention (CCDCP) researchers say tuberculosis (TB) and malaria drugs are structurally similar and may assist in developing vaccine, reported South China Morning Post.


According to a published paper in the mBio journal, the CCDP study found that microorganisms that cause TB and malaria are parallel to the African swine fever's (ASF) critical structure.


Led by Professor Gao Fu, virology expert at the CCDCP, the study examined an enzyme, specifically the E165R enzyme, that safeguards the DNA of the virus. Developing a drug that can disable the enzyme is key to eradicating ASF.


Professor's Gao's team removed the protein from the virus. A special mixture of chemicals was used to crystallise the protein and create a sharper three-dimensional structure. Through a high-definition electron microscope, the team was able to conduct research in detail where the enzyme's chemical reactions and molecular binding occur.


It was through this method that the team discovered its structure is nearly the same to TB or malaria-causing bacteria or parasites. The team deduced that drugs developed to inhibit TB and malaria in humans could be the crucial foundation to developing a drug that inhibits the E165R enzyme in ASF as well.


In the last few months, a Chinese Academy of Sciences and Harbin Veterinary Research Institute team discovered in exceptional detail the overall structure of the ASF virus. The results, published in Science Magazine August 2019, has supported efforts to develop an ASF vaccine that has not been tested.


Last month, a closed-door meeting was conducted in Beijing between the Chinese government and top global scientists and researchers. Herbal medicine was proposed as a treatment to prolong a swine's chance of surviving. Different vaccines for human use were also evaluated for its safety to be used on swine. No solutions were found that could be implemented on a large scale.  


ASF is difficult to cure as it has an extremely complex structure. This means higher resistance to drugs and through mutation, can easily bypass a swine's immune system.


An experimental vaccine was given to 500,000 swine in the 1960s. While the vaccine was effective in lab tests, a quarter of the swine either died or fell ill from side effects, such as pneumonia.


The spread of ASF in China has resulted in more than one million swine culled and a 70% increase in pork prices because of the shortfall in supply.


- South China Morning Post