title: Porcine reproductive and respiratory syndrome virus in Ontario, Canada 1999 to 2010: genetic diversity and restriction fragment length polymorphisms.
abstract: Classification of Ontario porcine reproductive and respiratory syndrome virus (PRRSV) field isolates (n = 505) from 1999 to 2010, based on a global type 2 PRRSV ORF5 phylogenetic framework, revealed genetic diversity comparable to PRRSV in the USA, with sequences assigned to five of 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 USA. Mapping of 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 in differentiating strains at the local farm level.
authors.affiliation: School of Biological Sciences, The University of Hong Kong, Hong Kong SAR.
authors.forename: Manreetpal Singh
authors.initials: MS
authors.lastname: Brar
authors.affiliation: School of Biological Sciences, The University of Hong Kong, Hong Kong SAR.
authors.forename: Mang
authors.initials: M
authors.lastname: Shi
authors.affiliation: University of Guelph, Laboratory Services Division, Animal Health Laboratory, Box 3612, Guelph, ON N1H 6R8, Canada.
authors.forename: Li
authors.initials: L
authors.lastname: Ge
authors.affiliation: University of Guelph, Laboratory Services Division, Animal Health Laboratory, Box 3612, Guelph, ON N1H 6R8, Canada.
authors.forename: Susy
authors.initials: S
authors.lastname: Carman
authors.affiliation: Department of Veterinary and Biomedical Sciences, St Paul, University of Minnesota, MN, USA.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Murtaugh
authors.affiliation: School of Biological Sciences, The University of Hong Kong, Hong Kong SAR.
authors.forename: Frederick Chi-Ching
authors.initials: FC
authors.lastname: Leung
mesh_terms: D000818:Animals; D014644:Genetic Variation; D008969:Molecular Sequence Data; D009864:Ontario; D010802:Phylogeny; D012150:Polymorphism, Restriction Fragment Length; D019318:Porcine Reproductive and Respiratory Syndrome / Q000821:virology*; D019316:Porcine respiratory and reproductive syndrome virus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification*; D013552:Swine