Characterization of three African swine fever viruses from different clinical settings revealed a potential attenuation mechanism

Abstract

Abstract African swine fever (ASF) is an acute and fatal hemorrhagic disease in domestic pigs and wild boars caused by African swine fever virus (ASFV) that currently threatens the pig industry worldwide. Since the 2018 ASF outbreak in China, ASFV has evolved and caused diverse clinical manifestations, such as chronic and asymptomatic infections. Therefore, it is important to understand the molecular mechanisms underlying ASFV attenuation in the field. Here, we isolated three ASFVs from one diseased and two asymptomatic pigs by using primary porcine alveolar macrophages (PAMs) from both domestic pigs and Bama minipigs. The three ASFVs exhibited similar phenotypes in cell culture, including cytopathic effects (CPEs), hemadsorptions (HADs), viral protein expressions and growth curves. Genome sequencing revealed that all three ASFVs were genotype II strains. Genomic comparisons suggested that the disruption of the viral genes MGF360 and MGF110, rather than EP402R and EP153R, is likely involved in the potential attenuation of ASFV via the upregulation of innate immune responses.

Keywords

• African swine fever virus
• Virus isolation
• Genome sequence
• Genotype II
• Attenuation