Category Research project
  • Mikrobiologie

Survival of African swine fever virus in feed, bedding materials and mechanical vectors and their potential role in virus transmission

Project status
Completed
Project start
2022
Project end
Jan 2024
Acronym
ASF-Feed
Department
Sicherheit in der Nahrungskette

Description and Objective

In recent years, African swine fever (ASF) has become a pandemic and within the European Union, affected wild boar populations are the main drivers of the epidemic. This situation presents new challenges, such as the need for a risk assessment for agricultural products harvested in affected regions that are at risk of exposureExposureTo glossary to carcasses or body fluids from affected animals. Direct contact with susceptible pigs (feeding or use as employment material) or movement of contaminated matrices into free regions with potential contact with domestic or wild suidae may pose a risk. When contacting susceptible suidae, infection biology must be considered. Despite the fact that the oral or oronasal route of transmission is much less effective than the parenteral route, studies have provided evidence that small amounts of virus can be sufficient to infect susceptible pigs, especially if exposure is repeated. Therefore, any potential contamination with infectious virus may be critical, especially considering the rather high persistence of ASFV. In connection with outbreaks and the spread of ASF virus in the environment, animal feed has been and continues to be brought into play as a possible vector. However, the data situation is not good. This "lack of data" has already been identified by EFSAshort forEuropean Food Safety Authority and BfRshort forGerman Federal Institute for Risk Assessment. Within the framework of the research project, some of these data gaps are now to be filled.

Result

Over the last years, African swine fever (ASF) has gone pandemic and within the European Union affected wild boar populations are main drivers. This brings new challenges, i.e. risk assessment needs for agricultural products and the role of mechanical arthropod vectors. Answering the call “Survival of African swine fever virus in feed, bedding materials and mechanical vectors and their potential role in virus transmission” (GP/EFSAshort forEuropean Food Safety Authority/ALPHA/2021/09), relevant feed and bedding materials were chosen for stability experiments. All matrices were contaminated with ASFV and stored at five different ambient conditions (-20°C, 4°C, 10°C, 20°C, and 37°C) over a period of up to nine months. Replicate samples were evaluated at different time-points using real-time PCRs and virus isolation. Additionally, the possible role of three types of blood-sucking arthropods was assessed. In detail, studies were carried out on how long representative arthropods harbored viral genome and infectious virus upon feeding on infectious blood. In a last step, further proof-of-concept data were generated on the transmission of ASFV via ingestion of (small) arthropods after an infected blood meal. Concluding, detection of infectious virus was rather limited in most matrices while detection of viral genome was possible over the entire study period. At lower temperatures, however, the virus was stable on feed matrices over several days or even weeks, especially on beet and potatoes. Grass, grass silage and corn silage did not allow re-isolation of virus at any time-point. The studies on the detectability of the virus in arthropods showed that the virus is generally detectable for a certain period of time depending on temperature and ingested volume. The detectability of virus in stable flies exceeded the expectations with over 168 hours at cool temperatures. The feeding experiment did not lead to infection of pigs. However, the power of this proof-of-concept study is limited.
Type of project

Third-party funded project

Research focus

Futtermittelsicherheit / Gesundheit von Mensch, Tier und Umwelt (One Health) / Expositionsabschätzung und Bewertung biologischer Risiken / Forschung zur Sicherheit nationaler und internationaler Warenketten

Organisational units and partners

Lead specialist group: Futtermittelsicherheit, Stofftransfer in der Nahrungskette (8FZ)
Contact persons: Dr. Anneluise Mader, Dr. Bettina Wagner, PDshort foroutside lecturer Dr. Robert Pieper, Dr. Janine Kowalczyk
External partner: Friedrich-Loeffler-Institut, Bundesforschungsinstitut für Tiergesundheit, Swedish National Veterinary Institute

Funding body and grant number

Europäische Behörde für Lebensmittelsicherheit
GP/EFSAshort forEuropean Food Safety Authority/LPHA/2021/09

Publications

https://doi.org/10.2903/sp.efsa.2024.EN-8776

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