This study tested transmission of a recent European African swine fever virus isolate, from Poland in 2015, by direct contact and by aerosol. Pigs exposed by intranasal inoculation, by direct contact with infected animals, and by aerosol all developed acute disease. It is the first aerosol transmission study conducted with a contemporary European isolate.
The result confirms with a current strain what Wilkinson and colleagues demonstrated in 1977, when eight recipient pigs developed African swine fever after exposure to air ducted from loose boxes holding inoculated donors, and a group housed on a platform 2.3 metres above infected pigs also became infected. De Carvalho Ferreira and colleagues quantified ASFV in air from experimentally infected pigs in 2013 using an MD8 gelatine filter method. Li and colleagues then documented a complete aerosol transmission chain between two piggeries under field conditions in 2023.
Strain currency matters for this pathogen because the isolates circulating in Europe since 2007 differ from those studied in the 1970s, and a control decision made today rests on the behaviour of the virus that is actually moving. What this study establishes is that the aerosol route is not a historical artefact of old isolates. It should be read alongside the distance evidence, which places ASFV in the short range category, from zero to 150 metres, making it principally an intra site rather than an inter farm airborne concern.