ASF swine vaccine shows promise, but long journey ahead

The USDA's Agriculture Research Service (ARS) just accomplished an important first against one of the world's deadliest swine diseases. ARS scientists developed a vaccine for African swine fever (ASF) that protects hogs from the ASF strain found in Europe and Asia.

This news couldn't come at a better time for U.S. pork producers. The lethal swine disease now infects hogs in Haiti and the Dominican Republic, just several hundred miles away from U.S. shores.

But the vaccine has a long road ahead before the U.S. and other countries use the vaccine, according to Scott Dee, DVM, researcher with Pipestone Veterinary Services, Pipestone, Minnesota. His research includes work on ASF. Pipestone is third on this year's list of Successful Farming's Pork Powerhouses annual look at the top U.S. producers.

"People think we have to get a vaccine, but there's a lot of caveats that go along with it," he said.

COMPLICATED VIRUS

"First, [scientists] have been trying to make a vaccine for the ASF virus for decades," Dee explained. "The virus is very large and that makes it hard to determine which piece of the virus is important to stimulate immunity.

"USDA has made some good progress. They have a vaccine candidate based on a Georgia strain, the prevalent virus in Asia and Europe. Looking at their small, lab-based trials, which is how you start, they have shown the ability to protect pigs vaccinating and then challenging later. It's a good first step. And scientifically, it is big news because this has not been done before."

However, the vaccine works only against one strain, Dee pointed out. Its protection against other ASF strains has not been tested. But the strain it works against is a significant one.

Another conundrum: The U.S. is negative to ASF, and the use of an ASF vaccine would trigger a shutdown of the U.S. export market. Currently, no test can distinguish between an ASF vaccine and the wild ASF virus.

"ASF vaccine use to me is only dependent on if we get the virus," he said. "The value is we can save pigs because the wild ASF virus kills close to 100% of the pigs it infects. It's a terrible virus.

"But we simply can't vaccinate our country and expect to maintain export markets, unless there's some agreements or monitoring system that everyone is in favor of."

And finally, pork producers will not be able to order a vaccine for a long time, Dee added. The vaccine faces years of test trials to prove it works and it is safe, followed by manufacturing on a large scale.