Virus recovery from sterile sand, beach sand, swamp mud, and
forest soil on macrophages (Experiments 2 and 3)
Three different soil types (beach sand, swamp mud, forest soil) were
inoculated with blood from an ASFV infected wild boar and stored at room
temperature for up to three weeks. A blood-only control and sterile sand
mixed with infectious blood were carried along as process controls under
the same conditions. In these experiments, virus titers in pure blood
remained stable over the three-week storage period at room temperature
and no decline in virus titers was observed after two weeks (Figure 4).
Virus titers in the sterile sand control, however, decreased constantly
over time. Nevertheless, both process controls (blood-only and sterile
sand) contained infectious virus over the entire observation period.
In beach sand, high virus titers between 5.50 log10HAD50/mL and 6.50 log10HAD50/mL were observed directly after application of
infectious blood (0h), but no infectious virus could be detected from
three days until the end of the experiment (Figure 4). In contrast, no
infectious virus could be recovered from either forest soil specimen (pH
4.1 and 3.2), even immediately after the application of infectious
blood. In swamp mud (pH 5.1), however, low residual titers were found
directly after the addition of infectious blood. From day three until
the end of the observation period, no infectious virus was recovered
from swamp mud.
ASFV genome, however, was detectable in all investigated soil
types/matrices and no distinct decline in copy numbers was recorded over
the entire observation period.