Porcine reproductive and respiratory syndrome virus in Ontario, Canada 1999-2010: genetic diversity and restriction fragment length polymorphisms

Abstract

Classification of PRRSV field isolates (n = 505) in Ontario from 1999-2010, based on a global type 2 PRRSV phylogenetic framework, revealed genetic diversity comparable to PRRSV in the United States, with isolates in five out of the nine lineages (1, 2, 5, 8, and 9). Importantly, the tree topology indicated a Canadian ancestry for the highly virulent MN184-related strains that first emerged in 2001 in the United States. Mapping the RFLP patterns onto the phylogenetic tree revealed numerous examples of different RFLP patterns located within the same phylogenetic cluster. Statistical analysis showed occurrences where similar RFLP patterns masked diverse genetic distances and instances of close genetic proximity with divergent RFLP patterns. Collectively, extensive genetic diversity prevails in type 2 PRRSV in one region of the North American swine industry, and it is not described adequately by RFLP typing which might have value at the local farm level.

Brar M S, Shi M, Ge Li, Carman S, Murtaugh M P, Leung F C. 2011. Porcine reproductive and respiratory syndrome virus in Ontario, Canada 1999-2010: genetic diversity and restriction fragment length polymorphisms. Journal of general virology [accepted].