Researchers move step closer to wild boar ASF virus

Scientists have published details of research showing 'promising' signs that a vaccine could be developed to help stem the spread of African swine fever (ASF) in wild boar.  

The scientists from Spain demonstrated that oral immunisation of wild boar with an attenuated ASF virus of genotype II isolated in Latvia in 2017 conferred 92% protection against animals challenged with a virulent ASF virus isolate.

This protection helped animal survive the disease and also reduced the level of ASF-compatible clinical signs, pathological findings, and virus detection in target tissues.

“This is, to our knowledge, the first report of a promising vaccine against ASF virus in wild boar by oral administration,” the researchers said in an article in the Frontiers in Veterinary Science journal.

“Further studies should assess the safety of repeated administration and overdose, characterize long-term shedding and verify the genetic stability of the vaccine virus to confirm if (the vaccine) Lv17/WB/Rie1 could be used for free-ranging wild boar in ASF control programs.”

The researchers describe ASF as the most significant threat to the pig industry worldwide, having spread to more than 55 countries on three continents.

Wild boar are the most severely affected host and the researchers highlight the lack of an available vaccine, along with the continuous movement of infected-wild boar populations among regions and trade activities, as the main reasons for the ‘unprecedented and constant spread of ASF in Europe’

“In the current context of this transboundary disease, an oral vaccine against ASFV in wild boar is urgently needed as an additional tool to reinforce and re-design mitigation plans owing that none of the control measures applied in affected wild boar populations has been effective,” the scientists say.

“If the safety of Lv17/WB/Rie1 as a vaccine can be established, then it may help mitigate the uncontrolled spread of ASFV across Europe, similar to the success so far in halting the spread of classical swine fever.”

The scientists want to set in motion future studies to examine the vaccine’s safety following repeated administration or overdose, its genetic stability, its stability in the field and the ability to differentiate it from infecting virus-based on DIVA serological testing for ASF.