Abstract Porcine reproductive and respiratory syndrome virus-type 2 (PRRSV-2) is a rapidly evolving RNA virus with major impacts on global swine production. To support epidemiological surveillance and characterization of viral diversity, a phylogenetic lineages and sub-lineages classification system has been developed for PRRSV-2. However, continued viral evolution and expanding molecular surveillance highlight the need for a coordinated global framework to maintain and update nomenclature.
