ASF vaccine moves forward in China; study questions ASF spread in feed

An African swine fever vaccine in China will begin expanded trials, after an initial study found it to be safe.

Scientists at the Harbin Veterinary Research Institute inoculated about 3,000 fattening piglets and sows with 10 to 100 times the proposed immunization dose, China’s Ministry of Agriculture and Rural Affairs said in a statement. They found no clinical abnormalities or signs of disease, nor transmission of the vaccine virus or adverse growth and reproductive effects during a 20-week observation phase, Bloomberg reported.

The experimental vaccine generated at least 80% immune protection depending on the dose administered, the research showed. According to the ministry, the Chinese Academy of Agricultural Sciences will continue to accelerate research to obtain the necessary safety clearance and registration for the candidate vaccine.

Study raises questions about ASF in feed

A recent study out of Spain questions previously held beliefs about how ASF spreads through animal feed.

The study, reported on by Feed Strategy, attempted to replicate results showing that a relatively low dose of the virus could infect swine if present in feed. But after two weeks of continuous feeding on feed contaminated with at least the minimum infectious dose, the 30 pigs in the study failed to become ill.

One key difference between the new study and previous ones was that the new one used feed mixed with contaminated liquid unprocessed plasma, rather than spray-dried plasma, said Javier Polo, a researcher at APC. The manufacturer of blood-derived functional plasma proteins co-led the research.

“It is unknown if spray-dried plasma provided in feed could reduce incidence of ASFV transmission or expedite ASFV clearance in surviving infected pigs,” Polo told Feed Strategy. “This is an area in which we are interested to research.”

According to Polo, “feed and feed ingredient suppliers using good manufacturing practices including high biosafety standards represent a very low risk of ASFV spread.”