Marty Misener from South West Ontario Veterinary Services, How Long Does ASFV Survive In Various Soil Types?

Understanding the ecology and transmission of African swine fever virus (ASFV) is essential to minimizing virus spread. We have discussed previously the ability of ASFV to survive for extended time periods in animal products and decomposing carcasses (months) . The ASFV genome has been identified in environments surrounding infected farms but survival of infectious virus in various soil types has been less well described. These German researchers spiked various soil matrices with ASFV-positive blood from infected wild boar to see if ASFV can remain infectious in the soil beneath an infected carcass.

The researchers found the following:

  • ASFV genome detection was possible over the entire sampling period of the study. (Not a big surprise.)
  • Infectious ASFV was demonstrated in specimens originating from the following soil types
    • sterile sand for at least three weeks
    • beach sand for up to two weeks
    • yard soil for one week
    • swampy soil for three days
    • two acidic forest soils yielded no infectious virus
    • citric acid or calcium hydroxide (slaked lime) resulted in complete inactivation of virus in all soil types.

Take Home Messages:

  • Soil pH, structure, and ambient temperature played a role in the stability of infectious ASFV.
  • ASFV survival in acidic forest soils is poor but survival in sandy soils is quite good.
  • Mitigants such as citric acid or calcium hydroxide applied to soils where ASF positive carcasses have been detected can be a useful tool in reducing environmental transmission.

Ref:   Jolene Carlson  Melina Fischer , Laura Zani , Michael Eschbaumer , Walter Fuchs , Thomas Mettenleiter , Martin Beer , Sandra Blome   Stability of African Swine Fever Virus in Soil and Options to Mitigate the Potential Transmission Risk  Pathogens . 2020 Nov 23;9(11):977. doi: 10.3390/pathogens9110977.