Reverse genetics study disclaims the role of African swine fever virus gene I196L in the pathogenesis in pigs.

African swine fever virus (ASFV) genome encodes over 170 genes, but only a small number have been investigated for their roles in disease progression. Understanding the genetic and biological functions of these lesser-known genes accelerates the specification of open reading frames involved in pathogenesis in host animals and the development of ASF vaccines. In this study, we deleted the I196L gene of the highly virulent parental strain AQS-C-1-22 to generate the ASFV mutant AQSΔI196L. In vitro, AQSΔI196L replicated similarly to the parental virus in immortalized porcine kidney macrophage cultures. Pigs intramuscularly inoculated with 102 median tissue culture infectious dose (TCID50) AQSΔI196L developed similar clinical signs and consequences (e.g., high fever, anorexia, and death) as infections with the parental strain. However, viremia in AQSΔI196L-inoculated pigs was slightly reduced compared with pigs inoculated with the parental strain. These findings suggest that the I196L gene does not significantly affect the pathogenicity of the virus in pigs.