Recovery of infectious WSL-adapted CD2v-deleted ASFV Kenya and disinfection treatments (Experiment 4)
To evaluate the improved cell culture technique using WSL cells (see Figure 5), beach sand or yard soil were inoculated with blood spiked with WSL-adapted CD2v-deleted ASFV Kenya and stored at room temperature for three weeks. Furthermore, the different matrices were treated with two different disinfectants for one or three hours. A blood-only control and sterile sand mixed with infectious ASFV-blood were used as process controls under the same conditions.
Virus titers in the blood-only and sterile sand controls remained constant over the entire observation period, no decrease in virus titer was observed (Figure 6). Thus, untreated blood or sterile sand were infectious for the entire test interval of 3 weeks. Inoculated beach sand and yard soil however, displayed a steady decline in virus titer over time (during the first week). After one week a high variability between the biological replicates was observed in the beach sand. Moreover, in both soil types, no infectious virus could be detected after two weeks storage at room temperature.
Regardless of the matrix/soil type (sterile sand, beach sand, yard soil), no infectious virus could be recovered after a one-hour disinfectant treatment (calcium hydroxide or citric acid) at either concentration (Figure 5). ASFV in pure blood was also fully inactivated after treatment with either disinfectant for one hour at room temperature. In all tested matrices, ASFV genome copy numbers were relatively constant over time. In disinfectant-treated samples, slightly fewer genome copies were detected (Figure 6).