February 8, 2021

 

Researchers in China discover natural mutation in African swine fever virus

 

Researchers in China have discovered a natural mutation in the African swine fever (ASF) virus that may be less deadly that the strain that devastated China's swine herds in 2018 and 2019, Reuters reported.

 

The findings were published in Chinese Journal of Veterinary Science, February edition, and follows intense discussions in the industry about the evolution of ASF. There are currently no approved vaccines for ASF.

 

The researchers, who come from the Military Veterinary Institute in Changchun, said there is an increased trend of lower mortality swine infected by ASF with more clinical symptoms that isn't easy to detect and is tough to control.

 

These characteristics are part of strains made for use in illegal vaccines.

 

However, the researchers said it is normal for natural ASF variants to appear as the virus has been circulating in China for a prolonged period.

 

Latvia and Estonia have also reported less virulent ASF strains in recent years.

 

Hu Rongliang and colleagues at the institute under China's People's Liberation Army said the new HuB20 strain was isolated from pork that was sampled at a Hubei province market.

 

The new strain had a partial deletion of the CD2v gene and an adjacent 8CR gene. Russia has reported prior research that proposed deletion of the two genes could protect swine from ASF.

 

The researchers said the variant does not contain known marker genes, which denotes that natural ASF variants are occurring in China and could be connected to the country's sub-acute ASF-epidemic.

 

Reuters had previously reported at least two new ASF strains that has been detected on swine farms in China, which appeared to be man-made due to the use of illegal vaccines. The genes in this new natural strain are different to those missing in the man-made variant. 

 

The researchers said there are working to validate the virulence of the new strain.

 

- Reuters