This diagnostic investigation sampled for African swine fever virus across a feed manufacturing and swine production system in Vietnam, covering manufacturing surfaces, distribution and production sites. ASFV was detected across those surfaces, and prevalence in feed samples was 0.70 percent. The work establishes feed and the equipment that handles it as a viable transmission pathway rather than a theoretical one.
Feed sits alongside the airborne route rather than competing with it. Guinat and colleagues in 2016 identified direct contact and contaminated feed as the principal routes of ASFV to domestic pigs, with aerosol transmission documented over short distances. Vasic and colleagues in 2024 recovered ASFV from feed, water, soil and insects during the Serbian outbreak. Havas and colleagues in 2023 found, on the PRRSV side, that the strongest protection came from air filtration and feed mitigation together rather than from either alone.
The low prevalence figure is worth reading carefully. A rate below one percent across sampled feed does not describe a small problem, because a single contaminated delivery reaching a naive herd is a complete event. It describes a detection challenge: surveillance built to find contamination at that frequency needs sampling intensity to match. For a producer, the operational point is that a filtered building with an unexamined feed chain has closed one door and left another open, and the two need to be addressed within one programme.