Analysis from UkrAgroConsult has traced new variants of the African swine fever virus recorded in China to illegal vaccines. Dr E Wayne Johnson, a pig veterinarian, explained that genetic analysis of the ASF viruses shows the same gene deletions found in unregulated vaccines.

“The ‘new virus’ circulating in China is the double-gene deleted vaccine virus. It lacks safety and its efficacy is not clear. This vaccine has deletions in the MGF360 locus and the CD2v locus which weakens the virus, but does not render it innocuous. It just produces a milder form of the disease,” he said.

Though it is possible for viruses to naturally mutate, Dr Johnson does not think this happened here. When speaking to Pig Progress, he said that the mutation was deliberately introduced into a substantial portion of China’s pig population. Illegal vaccines are the most likely culprit.

“Since the vaccine is unapproved, illegal, and officially forbidden, there is no reliable information on just how much vaccine was used and how much of the presence of the vaccine virus is due to secondary spread from pigs shedding the virus and transmission by fomites.”

He went on to say: “It is officially forbidden to vaccinate with the bootleg ASF vaccine but there are indications that vaccination is still continuing, as ASF is widespread in many regions of China and farmers feel desperate and consider that they have limited options. The introduction of the double-gene-deleted vaccine is an unwanted complication to a ghastly problem and an epidemiologic situation that is wildly out of control.”

Read the complete analysis on UkrAgroConsult.