This case study documents a complete chain of African swine fever virus transmission by aerosol between two piggeries under field conditions, monitored across 24 days. Virus was detected first in pigs in Room A, then in Room A aerosol on day 6, in air outlet dust on day 9, in outdoor aerosols the same day, in air inlet dust at Room B on day 15, and finally in Room B aerosols and pigs on day 21. Fluorescent powder was used to confirm the dust pathway between the buildings.
Before this work, controlled evidence for ASFV airborne transmission rested on experimental designs. Wilkinson and colleagues demonstrated it in 1977 by ducting air from infected donors to recipient pigs, and Olesen and colleagues repeated the demonstration in 2017 with a recent European isolate from Poland. De Carvalho Ferreira and colleagues quantified ASFV in air from experimentally infected pigs in 2013. The 2023 case study is the field counterpart to that experimental line. It shares a research group with the airborne transmission review published the same year by Hu and colleagues, so the two are not independent of one another.
The step that matters most for design is the dust intermediate. The chain did not run from exhaust air directly into intake air; it ran through dust deposited at the outlet and dust present at the inlet. That places settled and resuspended material inside the transmission path rather than beside it, which bears on inlet siting, on the separation between exhaust and intake, and on how surfaces around air handling openings are managed.