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.