The Swine Health Information Center reports the evolution of the African Swine Fever virus, as it moves through Asia, is complicating the diagnosis of the infection. The Swine Health Information Center’s continues to track the global movement of African Swine Fever.
SHIC Executive Director Dr. Paul Sundberg confirms scientists have seen some evolution in the virus, due in part to the use of unapproved gene deleted vaccines in Asia.
Clip-Dr. Paul Sundberg-Swine Health Information Center:
Those unapproved vaccines may cause an infection, may cause a low-level infection and sometimes when there are reports of different viral strains that are out there, it's rather difficult to separate the natural evolution of the virus itself, with the viral strains that may be used in unapproved vaccines.
That's a confounding issue, not easily separated. But the virus does seem to be changing. Whether it's the unapproved vaccine viruses or some evolution of the wild type virus, what we're observing is the opportunity for more chronic infection. ASF is still very pathogenic. It still will kill the majority of pigs that become infected.
There are opportunities for pigs to become chronically infected and to go ahead and continue to shed the virus and that's a real concern because that may mean that we have undetected virus infections out there and that could be a concern for being able to quickly identify and quickly respond to viral outbreaks.Source : Farmscape