A new variant of African swine fever has emerged on the mainland with a strong ability to spread

The National Specialized Laboratory of African Swine Fever at the Harbin Institute of Veterinary Medicine, Chinese Academy of Agricultural Sciences, published a study on African swine fever in the online edition of the journal China Science Life Sciences on Feb. 26.

The institute conducted active surveillance and epidemiological investigations, collected, tested and analyzed 3,522 pathogenic samples from Heilongjiang, Jilin, Liaoning, Inner Mongolia and Shaanxi from June to December last year in response to the African swine fever outbreak, and identified and tested 138 suspected infected samples sent by some provinces and cities.

According to the study, the genome sequences of the 2020 isolates were altered to varying degrees, including nucleotide mutations, deletions, insertions or short fragment substitutions, compared to the earliest isolate HLJ/18 identified in 2018.

It was found that at least four or more naturally variant strains of low lethality gene type II existed. Although the pathogenicity was reduced compared to typical strong strains, they showed significant residual virulence and had a high capacity for horizontal transmission.

Researchers said that these mutant strains have a certain degree of insidious clinical manifestations, making early diagnosis more difficult, and that counter strategies should be developed and adopted as soon as possible.

In January, a new type of African swine fever was discovered on the mainland, and on the evening of January 21, the city of Meizhou in Guangdong Province issued an emergency notification of a new wave of African swine fever. A new strain of African swine fever has emerged in the large pork producer “New Hope Liuhe” on the mainland, with more than 1,000 sows and fattening pigs infected.

According to reports, this new strain of virus can remain on pork for several months and is likely to infect farmed pigs that feed on Food waste through pork, threatening to significantly reduce pork production on the mainland and increasing the risk of further spread worldwide.

The African swine fever outbreak has not stopped since August 2018 on the mainland.