African swine fever: transmission via feed unlikely
African swine fever (ASF) continues to spread in Europe and other parts of the world. Food also plays a role in this. If unheated food or leftovers from infected animals are fed to uninfected animals, the virus can spread to previously ASF-free regions and thus also to domestic pig herds. As the pathogen is stable in the environment, it has long been assumed that it can also be transmitted via feed, water and other materials. The European Food Safety Authority (EFSA) initiated an international research project to answer this question. The German Federal Institute for Risk Assessment (BfR) and the Friedrich-Loeffler-Institut (FLI) participated in this project. The results show that ASF viruses are only expected to spread via feed in special cases. “Even after adding large quantities of the infectious virus to various feed and bedding materials, no infectious virus was detectable after a short period of time”," says project coordinator Dr Sandra Blome from the FLI, ”Only in cold-stored fodder beet and potatoes was infectious virus material still found in some samples even after a longer storage period. This is probably due to the fact that ASF viruses are particularly stable in cold temperatures and humid environments”." “Basically, ASF viruses are not transmissible to humans”, explains BfR President Professor Andreas Hensel. “With this project, however, we are closing an important knowledge gap regarding the role of feed in the transmissibility of the ASF virus”.
Due to a lack of empirical data, the FLI worked together with the BfR and the Swedish Statens Veterinärmedicinska Anstalt (SVA) in the EFSA-funded project (start 2022) to close the existing knowledge gaps. The aim was to investigate the stability of ASF viruses on feed, bedding materials and mechanical vectors under practical storage conditions. For this purpose, 14 relevant agricultural feed and bedding materials were used: Grass, grass silage, hay, bark, peat, wood shavings, maize silage, rapeseed, barley, wheat, oats, straw, potatoes and fodder beet.
All materials were contaminated with the ASF virus and stored at five different ambient temperatures for up to nine months. The samples were analysed at different times for infectious viruses and genome residues of the virus. The researchers also looked at the possible role of three different species of blood-sucking arthropods (arthropods such as seiners) to find out how long the arthropods studied can harbour the virus genome and the infectious virus after the intake of infectious blood.
The final report on the research project can be found at the following link: https://efsa.onlinelibrary.wiley.com/doi/epdf/10.2903/sp.efsa.2024.EN-8776
Further information on African swine fever on the BfR website
Questions and answers on African swine fever https://www.bfr.bund.de/de/fragen_und_antworten_zur_afrikanischen_schweinepest__asp_-203338.html
BfR communication, Is African swine fever also transmitted through feed?
https://www.bfr.bund.de/cm/343/wird-die-afrikanische-schweinepest-auch-durch-futtermittel-uebertragen.pdf
Further information on African swine fever on the FLI page
https://www.fli.de/de/aktuelles/tierseuchengeschehen/afrikanische-schweinepest/
About the BfR
The German Federal Institute for Risk Assessment (BfR) is a scientifically independent institution within the portfolio of the Federal Ministry for Food and Agriculture (BMEL). The BfR advises the Federal Government and the Federal States on questions of food, chemicals and product safety. The BfR conducts independent research on topics that are closely linked to its assessment tasks.
About the FLI
As a federal research institute for animal health, the Friedrich-Loeffler-Institut (FLI) is dedicated to the health of food-producing animals. Its central tasks are the prevention, diagnosis and control of animal diseases, the refinement of animal husbandry and nutrition as well as the conservation and utilisation of animal genetic resources.
This text version is a translation of the original German text which is the only legally binding version.