Pigs finishing

After years of research, a promising candidate for an African swine fever vaccine has been developed by USDA scientists.

It is offering protection from an ASF strain that developed in the Republic of Georgia in 2007 — the strain that has spread across much of southeast Asia and into Europe over the past 18 months, said David Pyburn, chief veterinarian for the National Pork Board.

“This is the most promising candidate I have seen come along,” Pyburn said. “We need to move forward with it as soon as we can.”

USDA researchers said removal of a “previously uncharacterized gene” resulted in complete protection for pigs.

“Limited cross protection studies suggest that in order to ensure a vaccine is effective, it must be derived from the current outbreak strain or at the very least, from an isolate with the same genotype,” the researchers said in their report.

The research indicated pigs infected with the genetically modified virus show no virus shedding — a key element in a successful vaccine, Pyburn said.

“None of the previous candidates were able to preclude viral shedding,” he said.

Pyburn said several private companies are also working on a vaccine. He added the size of the virus makes it even more of a challenge for scientists.

“There are at least 24 genotypes with ASF, and we know very little about cross protection,” he said. “This strain is the 2007 strain found in Georgia, but if we see another strain, there may not be cross protection.”

Additional research needs to be done to ensure the new vaccine is safe.

“Sometimes you vaccinate and if it’s not still the original strain, it can be just as bad as the disease itself,” Pyburn said.

He said developing this particular vaccine could continue for several years. Studies need to be conducted on larger groups of pigs to make sure it is effective and safe. That also takes money, Pyburn said.

“Right now, to my knowledge, there is no commercial partner for this vaccine,” he said. “We need this so we can transfer the technology to a commercial partner so we can start developing a supply of the vaccine.”

Pyburn said despite the possibility that a commercially available ASF vaccine may be years down the road, he is hopeful progress will continue to be made, and that the U.S. pork industry will continue to fight to keep the deadly virus out of the country.

Sign up for our weekly CropWatch newsletter

* I understand and agree that registration on or use of this site constitutes agreement to its user agreement and privacy policy.

Jeff DeYoung is livestock editor for Iowa Farmer Today, Missouri Farmer Today and Illinois Farmer Today.