The Executive Director of the Swine Health Information Center says all indications are that existing PCR tests will be able to detect an African Swine Fever variant caused by the use of unapproved African Swine Fever vaccines in China. African Swine Fever continues to circulate in China and some of the new outbreaks have been linked to the use of vaccines derived from live virus with two genes deleted.
Dr. Paul Sundberg, the Executive Director of the Swine Health Information Center, explains, while these vaccines are keeping pigs alive in China, those pigs remain infectious and there are concerns with the ability to detect virus caused by the vaccine.
Clip-Dr. Paul Sundberg-Swine Health Information Center:
Especially when you have a gene deletion in a virus, you want to make sure that your PCRs that detect virus don't key on those genes that have been deleted because, if they do, then your PCR is not going to find it.
It may be a live virus that's able to be spread but your PCR's not going to be able to find it if it keys on that gene that has been deleted. So went to USDA and we asked them directly about these two gene deletion virus strains that are being used as vaccines. According to the information that they have and looking at what they use as PCRs, what the laboratories use, we should be able to still detect that two gene deletion variant of ASF should it get to North America.
So I think right now we're still at the same spot. That gene deletion virus is circulating, it sheds, it causes chronic infection and it sheds but we are able to detect it in North America I believe given the current information that we've got, so that's good news.Source : Farmscape