ASFV in feed: study improves half-life estimates

A study by Kansas State University provides more accurate half-life measurements that confirm African swine fever virus (ASFV) can survive a simulated 30-day transoceanic voyage in contaminated plant-based feed and ingredients. Their findings are published in Emerging Infectious Diseases.

The research team, headed by Megan Niederwerder, assistant professor of diagnostic medicine and pathobiology in the College of Veterinary Medicine, looked at the degradation of ASFV in 9 feed ingredients.

“This study provides additional evidence supporting the potential risk that feed may play in the transboundary movement of African swine fever,” Niederwerder said.

The half-life of ASFV in the feed ingredients ranged from 9.6 to 14.2 days after exposure to varying temperature and humidity conditions simulating transoceanic shipment. This means it would take approximately two weeks for the total viable virus concentration to decay by half its original count under the conditions of a transatlantic voyage. Niederwerder said that all feed matrices provided a more supportive environment for viral stability when compared to media, where the shortest half-life was calculated.

The new study expands on Niederwerder’s previous work confirming the likelihood of African swine fever transmission through feed.

“Transmission of swine viruses through feed has been recognized as a risk since around 2013, but the probability of African swine fever virus infection through plant-based feed was unknown until our publication earlier this year,” Niederwerder said. “Our research reports novel data and important quantitative information that can be incorporated into risk models for introduction and mitigation of African swine fever virus through imported feed ingredients.”

Article: Stoian, A.M.M., Zimmerman, J., Ji, J., Hefley, T.J., Dee, S., Diel, D.G., Rowland, R. R. R., Niederwerder, M. C. (2019). Half-life of African swine fever virus in shipped feed. Emerging Infectious Diseases, vol. 25, no. 12, doi: 10.3201/eid2512.191002

[SOURCE: Kansas State University]