Efficacy of Liming Forest Soil in the Context of African Swine Fever Virus

Abstract

Since September 2020, Germany has experienced the first ever outbreak of African swine fever (ASF). The first known cases occurred exclusively in wild boar in forest areas in Brandenburg and Saxony; in July 2021, infected domestic pigs were also confirmed for the first time. As wild boar are considered the main reservoir for the virus in the European region, an effective interruption of this infection chain is essential. In particular, the removal and safe disposal of infected carcasses and the direct disinfection of contaminated, unpaved ground are priorities in this regard. For the disinfection, highly potent as well as environmentally compatible disinfectants must be used, which are neither influenced in their effectiveness by the soil condition nor by increased organic contamination. Thus, in this study, slaked lime, milk of lime and quicklime (1% to 10% solutions) were selected for efficacy testing against the test virus recommended by the German Veterinary Society (DVG), Modified Vaccinia Ankara virus (MVAV), and ASF virus (ASFV) in conjunction with six different forest soils from Saxony in two different soil layers (top soil and mineral soil) each. In summary, 10% of any tested lime type is able to inactivate both MVAV and ASFV under conditions of high organic load and independent of the water content of the soil. At least a 4 log reduction of the virus titer in all tested forest soil types and layers and by all applied lime types was observed. In conclusion, the high efficacy and suitability of all tested lime products against both viruses and in the presence of high organic load in forest soil can be confirmed and will help to control ASF spread.

Stability of African swine fever virus genome under different environmental conditions

“…The results of the pH investigations demonstrated that pH had a minimal effect on the ASFV genome. Similarly, the ASFV antibody was stable in both acidic and alkaline environments [40,41]. The previous studies by Galindo et al [42], Hernaez et al [43], and Sanchez et al [44] have suggested that ASFV infection into cells requires a low pH environment, that the disassembly of the coat and dissociation of the outer membrane processes are strongly dependent on an acidic pH, and viral particles show clear signs of disassembly and structural loss at a pH of <5.…”

“…The results of the pH investigations demonstrated that pH had a minimal effect on the ASFV genome. Similarly, the ASFV antibody was stable in both acidic and alkaline environments [ 40 , 41 ]. The previous studies by Galindo et al .…”

Impact of ASFV Detergent Inactivation on Biomarkers in Serum and Saliva Samples

“…Detergents can potentially produce high cytotoxicity in cell culture and can compromise the correct validation of the results. To this end, following the work of Tanneberger et al [ 17 ], the respective concentrations of the used detergents (0.05%, 0.1%, and 0.5%) were first titrated without virus and added to the corresponding cell culture in 96-well plates. The cell culture was incubated and tested for toxicity over 2 h. If cell toxicity (necrosis/detachment of cells) was observed during this time in one or more dilution levels, the respective dilution level was added to a 24-well plate containing cell culture.…”

African Swine Fever: A Review of Current Disease Management Strategies and Risks Associated with Exhibition Swine in the United States

“…Lime was unaffected by the presence of blood, indicating its usefulness in areas surrounding infectious carcasses that are likely to be tainted with blood and other bodily fluids. The appropriate decontamination of the soil where infected animals died is critical in curbing the further spread of ASFV, especially in countries such as Germany, where the virus has spilled over into the wild boar population [20].…”