How infectious is ASFv in feed exactly?


Vincent ter Beek, Pig Progress

Jul 30, 2020


How infectious is African Swine Fever virus in feed exactly? Recent Spanish research, revolving around liquid porcine plasma, indicates that the minimum infectious dose of African Swine Fever virus on feed may be higher than has been previously been assumed.


The research was carried out at the Animal Health Research Center IRTA-CReSA in Spain, in cooperation with functional proteins producer APC. It was recently published in the peer reviewed online journal PLOS One.


Can liquid porcine plasma infect pigs?


The researchers hoped to determine if commercially collected liquid porcine plasma contaminated with African Swine Fever virus (ASFv), and fed for 14 consecutive days, would infect pigs. To that end, they mixed commercially collected liquid porcine plasma with the serum from an ASFv experimentally infected pig.


Feed as risk factors for spreading ASF


The reason for this study was connected to a series of publications indicating that contaminated feed and porcine origin feed ingredients may be considered risk factors for the spreading ASF. In 2019, a US research team around Dr Scott Dee demonstrated that the virus can survive for 30 days under conditions of a transboundary simulation model.


In addition, another research by Dr Megan Niederwerder at Kansas State University, reported that ASF can be easily transmitted in water and feed. That research mentioned a minimum infectious dose of 104 TCID50 would be sufficient to infect 40% of the pigs.


In the newly published trials, the researchers used liquid porcine plasma instead of spray-dried porcine plasma, which would normally be used in feed diets. They wanted to avoid the inactivation effect of the spray-drying process on the virus. The use of non-treated liquid plasma would guarantee a high titre of live ASFv.


Trial set-up of study I ...


Trial set-up of study II ...


All pigs remained healthy in the feed trial ... 


Minimum infectious dose ...


more, including links