Recombined ASF Genotypes 1 and 2 Raise Concern Over Potential ASF Vaccine Effectiveness

Evidence of African Swine Fever recombination in China is raising concern over the potential long-term effectiveness ASF vaccines. Researchers in China have published a report outlining evidence of a recombination of African Swine Fever genotype 1 and genotype 2 viruses detected in pigs.

Dr. Paul Sundberg, the Executive Director of the Swine Health Information Center and a member of the Swine Innovation Porc Coordinated African Swine Fever Research Working Group, says this recombination gives reason to consider an increased risk.

Quote-Dr. Paul Sundberg-Swine Health Information Center:

Genotype 1 is a genotype that's in Africa, Italy and southern Europe that is relatively stable in the wild boar in those areas and relatively nonpathogenic.
It doesn't cause the problems that genotype 2 that's travelling around the world has caused now.

Genotype 2 is the one that moved up from Africa into eastern Europe in 2007 and has been moving around the world since.The genotype 2 is very virulent.
It causes our problems and it is also transmissible.

This recombination with genotype one is some concern because it has the opportunity to be as transmissible as the regular genotype 2.It also has the opportunity to be as virulent as genotype 2 but we're concerned about it because the genotype 1 may give it some ability to not be as virulent and not be as detectable as a genotype two by itself.

When you get two viruses together, even two genotypes of the same virus, and they are inside their hosts they have an opportunity for genetic material to transfer from one to another.

Dr. Sundberg says vaccines developed for one ASF genotype do not provide cross protection from other genotypes.He says, whether a vaccine that protects against genotype 2 will protect against a recombined virus, is still not known.