Researchers found “no appreciable decline in viral concentration” after 120 days of storage at 34°C (93.2°F). Gerald Shurson, professor of animal science at the University of Minnesota, noted that this challenges the reliance on extended storage as a mitigation strategy against the ASF virus.
The study used a surrogate virus structurally similar to the ASF virus but harmless to humans and livestock. The surrogate virus was introduced to common feed ingredients, including soybean meal, corn, dried distillers grains (DDGS), and complete feed, which were then stored. This research employed more sensitive testing methods compared to previous studies.
Key Findings of the Study:
- Extended storage of feed is not a reliable strategy for neutralizing the ASF virus.
- Stricter biosecurity measures are essential to prevent virus spread via contaminated feed.
- Chemical additives that deactivate the virus require renewed focus and research.
The researchers observed that the virus remained stable in soybean meal and other feed ingredients, including corn.
In the second phase of the study, contaminated feed was processed using a simulator replicating a pig's digestive system. Results showed that digestion could inactivate the virus in certain cases, depending on the feed composition. This variability may explain discrepancies in previous research, where some studies reported pigs falling ill after consuming low doses of ASF-contaminated feed, while others found pigs tolerated higher contamination levels.
Further research is needed to understand why certain feed ingredients and diets promote greater viral inactivation. Factors such as the mineral content (ash concentration) of feed appear to influence virus stability during digestion, but the exact mechanisms require additional investigation.
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