An update on genetic analysis of porcine reproductive and respiratory syndrome virus type 2 (PRRSV-2) in South America: identification of ORF5 sequences of lineage 1A, 1C and 1G.

Data regarding PRRSV-2 in South America are scant and a coordinated criterion for molecular characterization is needed. A phylogenetic analysis was performed using a dataset of 76 ORF5 sequences from South America, and results showed the identification of lineage 5 in the early 2000s and the predominance of lineage 1 at least since 2013. Lineage 1 sequences were further classified into sub-lineages according to a recent molecular characterization study of PRRSV-2 in United States. Our results revealed the recent identification in Uruguay of PRRSV-2 ORF5 sequences of lineage 1 sub-lineage C. Two additional sub-lineages were identified in South America, 1G in Chile and 1A in Peru. Continuous updating the molecular epidemiology of circulating viruses with coordinated investigations among countries is required to control and prevent the emergence of genetic variants of PRRSV-2.