First oral vaccination of Eurasian wild boar against ASFV genotype II

African swine fever (ASF) is the most significant threat to the pig industry worldwide. In the European Union (EU), wild boar (Sus Scrofa) populations are affected in several geographical areas, thus representing a possible reservoir for the persistence of the infection and an infection spreading factor difficult to control.

The potential use of this new vaccine would seek to reduce the number of susceptible animals, increasing herd immunity in wild boar populations and decreasing ASF incidence. The recent new emergency of ASF in Europe has increased the interest in the development of an effective vaccine against the disease. However the genetic complexity of the virus, the lack of information regarding the immunity of ASF, the difficulties in developing neutralizing antibodies and the technical problems in building stable line cells, have delayed the development of a suitable vaccine.

An article recently published in Frontiers in Veterinary Science by Dr. Jose Angel Barasona and collaborators describes the results of a successfully experimental vaccination of wild boars against ASF virus (ASFV). This experimental study shows how the oral immunization of wild boars of a commercial farm with a non-hemadsorbing attenuated ASFV of genotype II (Lv17/WB/Rie1) conferred 92% protection against challenge with a virulent ASF virus isolate (Arm07), currently circulating in Asia and Europe. The vaccine has been administered to the wild boars by bait, and following this route, the Lv17/WB/Rie1 strain used for this vaccine can induce an antibody response with no ASF-compatible clinical signs, without pathological findings and no virus detection in target tissues. Moreover, the study also shows an additional function to immunize other wild boar through contact with orally vaccinated animals. However, the authors consider this result as preliminary and long term studies are urgently needed to evaluate the ability of Lv17/WB/Rie1 to persist in the hosts and to be transmitted among sentinel wild boars. In the current context of this transboundary disease, if the safety of the vaccine can be established, it can help to keep the spread of ASFV across Asia and Europe under control.

Reference

https://www.frontiersin.org/articles/10.3389/fvets.2019.00137/full