GENETIC VARIATION AND PHYLOGENETIC RELATIONSHIPS OF PORCINE REPRODUCTIVE AND RESPIRATORY SYNDROME VIRUS (PRRSV) IN CANADA

摘要

Substantial variability in genomic sequences has been demonstrated among North American PRRSV isolates based on nucleotide sequencing of several open reading frames (ORFs). These studies have been performed mainly on field isolates from the United States. Little is known about the genetic population of PRRSV field strains in Canada in comparison with that of US. We have initiated a study in Quebec in the first trimester of 1998 to investigate the genomic and antigenic variation of currently circulating PRRSV strains. The study also aimed at comparing these strains with field isolates obtained in previous years (1991-1997). Finally, clinical and epidemiological data were collected via detailed questionnaires accompanying submitted samples to obtain informations regarding the association of particular strains with specific clinical signs, geographic distribution, temporal variation, and modes of transmission of PRRSV. We report here results from the genomic study along with some observations based on epidemiological data.