Analysis of Genetic Variation of Two NADC30-like Strains of Porcine Reproductive and Respiratory Syndrome Virus in China

Abstract

BACKGROUND NADC30-like strains of porcine reproductive and respiratory syndrome virus first appeared in Chinese swine herds in 2012. OBJECTIVE AND METHOD To explore the possible genetic diversity of these strains, we sequenced and analyzed the complete genomes of two NADC30-like strains. These isolates shared 95.4% homology with NADC30. RESULT The two strains displayed a discontinuous deletion of 131 amino acids in NSP2, mutations of amino acids in GP3 and GP5, and a 3-nucleotide deletion in the 3' untranslated region. Phylogenetic analysis showed that the two isolates formed a new branch and clustered in a subgroup with NADC30 isolates from North America. CONCLUSION We conclude that the above two NADC30-like strains may have been introduced from North America to China, where they acquired new genetic diversity.