Molecular Characterization of African Swine Fever Virus From 2019-2020 Outbreaks in Guangxi Province, Southern China.

African swine fever virus (ASFV) causes contagious hemorrhagic disease of pigs with high morbidity and mortality. To identify the molecular characteristics of ASFV strains circulating in Guangxi province, southern China, a total of 336 tissue samples collected from 336 domestic pigs that died as a result of severe hemorrhagic disease during 2019-2020 were tested for ASFV. Furthermore, 66 ASFV strains were genetically characterized by sequence analysis of the C-terminal region of () gene, the complete () gene, the variable region of () gene, the central variable region (CVR) of gene, the full gene, and the tandem repeat sequence (TRS) within intergenic region (IGR) between the and () genes. Phylogenetic analysis revealed that the ASFV strains from Guangxi province belonged to genotypes I and II based on the () and () genes, and there were eight different tetrameric TRS variants based on the CVR of gene. Phylogenetic analysis of the () gene revealed that these ASFV strains belonged to serogroups 4 and 8. Eight of the 66 strains belonged to genotype I and serogroup 4, and showed deletion of whole gene. The sequence analysis of the IGR between the genes showed that IGR II and III variants were co-circulating in Guangxi province. The results indicated that ASFV strains circulating in Guangxi province during 2019-2020 outbreaks showed high genetic diversity, of which genotypes I and II, as well as serogroups 4 and 8, were simultaneously circulating in Guangxi province, and there existed wild-type and naturally gene-deleted strains in the field. This is the first detailed report on the molecular characterization of the ASFV strains circulating in southern China, and serogroup 4 in China.