Abstract:
Since the initial report of African swine fever (ASF) in Kenya in 1921, the disease has
predominantly been confined to Africa. However, in 2007, an ASF genotype II virus of unknown
provenance was introduced to Georgia. This was followed by its rampant spread to 73 countries, and
the disease is now a global threat to pig production, with limited effective treatment and vaccine
options. Here, we investigate the origin of Georgia 2007/1 through genome sequencing of three
viruses from outbreaks that predated the genotype II introduction to the Caucasus, namely Madagascar
(MAD/01/1998), Mozambique (MOZ/01/2005), and Mauritius (MAU/01/2007). In addition,
genome sequences were generated for viruses from East African countries historically affected by
genotype II (Malawi (MAL/04/2011) and Tanzania (TAN/01/2011)) and newly invaded southern
African countries (Zimbabwe (ZIM/2015) and South Africa (RSA/08/2019). Phylogenomic analyses
revealed that MOZ/01/2005, MAL/04/2011, ZIM/2015 and RSA/08/2019 share a recent common
ancestor with Georgia 2007/1 and that none contain the large (~550 bp) deletion in the MGT110
4L ORF observed in the MAD/01/1998, MAU/01/2007 and TAN/01/2011 isolates. Furthermore,
MOZ/01/2005 and Georgia 2007/1 only differ by a single synonymous SNP in the EP402R ORF,
confirming that the closest link to Georgia 2007/1 is a virus that was circulating in Mozambique
in 2005.
