Molecular characterization of recent Korean porcine reproductive and respiratory syndrome (PRRS) viruses and comparison to other Asian PRRS viruses.
Twenty-eight PRRS viruses (PRRSVs) isolated from various pig farms in Korea between 2002 and 2003 were sequenced for open-reading frame (ORF) 5 and/or full-length genome and compared with numerous PRRSVs reported from North America, Europe and Asia. All Korean isolates examined were genetically of the North American genotype. The ORF5 sequence of one isolate was identical to Ingelvac PRRS MLV vaccine virus. ORF5 nucleotide sequence divergence of the remaining 27 Korean PRRSVs from VR-2332, the prototype of the North American PRRSV and parental strain of the MLV vaccine virus, ranged from 1.3% to 12.9%, which corresponded to 2.0% to 14.9% divergence at the amino acid level, raising a concern on the efficacy of the MLV vaccine. Phylogenetic analyses of ORF5 and/or full-length sequences revealed that the Korean PRRSVs formed a clade distinct from PRRSVs reported from other Asian countries (China, Taiwan, Japan, and Thailand). Our study demonstrated that PRRSVs of the North American genotype were introduced to the Korean swine population some time ago and have evolved independently from PRRSV in other Asian countries, suggesting that geographic separation might influence the molecular evolution of PRRSV. This should be taken into consideration when a national PRRS prevention and control policy for international trade is established.
Cha
Sang-Ho
SH
Division of Virology, National Veterinary Research and Quarantine Service, Anyang, Gyeonggido, Republic of Korea.
Choi
Eun-Jin
EJ
Park
Jong-Hyeon
JH
Yoon
So-Rah
SR
Song
Jae-Young
JY
Kwon
Jun-Hun
JH
Song
Hee-Jong
HJ
Yoon
Kyoung-Jin
KJ
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003132:Commerce; D019143:Evolution, Molecular; D014644:Genetic Variation; D005838:Genotype; D007723:Korea; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010802:Phylogeny; D019318:Porcine Reproductive and Respiratory Syndrome / Q000517:prevention & control / Q000635:transmission / Q000821:virology*; D019316:Porcine respiratory and reproductive syndrome virus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D016415:Sequence Alignment / Q000662:veterinary; D013552:Swine; D014759:Viral Envelope Proteins; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics*
D014759:Viral Envelope Proteins; D014764:Viral Proteins; C114789:glycoprotein 5, PRRSV