Project description:NADC30-like porcine reproductive and respiratory syndrome virus (PRRSV) has widely spread in China and become locally dominant virus strain in some provinces. Although they are not pathogenic as highly pathogenic PRRSV (HP-RRRSV) that outbreaks since 2006, NADC30-like PRRSVs distinguished themselves by high incidence of recombination with other virus strains which lead to change of virulence. The outbreaks of NADC30-like PRRSV in the vaccinated pig herds suggested that current commercial PRRSV vaccines cannot provide complete protection to the infection. In this review, we have described in detail the current situation of NADC30 PRRSV including epidemiology, genomic characterization, pathogenicity, and efficacy of current commercial vaccines in China.
Project description:The most recently emergent porcine reproductive and respiratory syndrome virus strains in China are characterized by 393 nucleotide deletions in the nonstructural protein 2 (NSP2) region and are known as NADC30-like strains. Here, we report the complete genome sequence of the NADC30-like HNjz15 strain that was isolated in 2015.
Project description:The NADC30-like strains of porcine reproductive and respiratory syndrome virus (PRRSV) are characterized by a 131-amino-acid deletion in nonstructural protein 2 (NSP2). Here, we report the complete genome sequence of a recombinant NADC30-like PRRSV strain, SCnj16, that exhibits the molecular marker of the Chinese highly pathogenic PRRSV (HP-PRRSV) in NSP2.
Project description:Here, we report the complete genome of an NADC30-like porcine reproductive and respiratory syndrome virus (PRRSV) strain, HNhx, which was isolated from Henan Province, China, in 2016 and was characterized by recombination with JXA1 strain (an epidemic highly pathogenic PRRSV strain in China) in Nsp4 to Nsp9.
Project description:NADC30-like strains of porcine reproductive and respiratory syndrome virus first appeared in Chinese swine herds in 2012.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.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.We conclude that the above two NADC30-like strains may have been introduced from North America to China, where they acquired new genetic diversity.
Project description:BACKGROUND:The recent emergence of NADC30-like porcine reproductive and respiratory syndrome virus (PRRSV) in vaccinated pigs arose more attentions for the high incidents of mutation and recombination of PRRSVs. FINDINGS:In this study, we determined full-length genome sequences of two NADC30-like PRRSV isolates from recent PRRSV outbreaks in China. Phylogenetic analysis showed that these two isolates were clustered in an independent branch together with NADC30, an American isolate in 2008. Genetically, HNjz15 shared 95.6 % nucleotide similarity to NADC30 without any exotic gene insertion. By contrast, HNyc15 shared 93.8 % similarity to NADC30 with recombination with VR-2332 and CH-1a. Two more previously reported NADC30-like PRRSVs were also analyzed and had exotic gene insertions with different PRRSV strains in their nonstructural protein genes. CONCLUSIONS:The above results showed the increased mutation and recombination rates of NADC30-like PRRSV under current vaccination pressure and a more pressing situation for the PRRSV eradication and control in China.
Project description:The name porcine reproductive and respiratory syndrome virus (PRRSV) NADC30-like was first coined in 2015. It originated from the NADC30 strain that was introduced into China by importing breeding pigs and has since undergone mutations or recombination, resulting in variant viruses. Following widespread outbreaks in China in recent years, these NADC30-like strains have presented major health challenges in swine production systems. Outcomes induced by PRRSV NADC30-like infection are highly variable, ranging from inapparent to severe, depending on the recombination between NADC30 and field PRRSV strains prevalent in swine farms. Vaccines and strict biosecurity measures have been explored to fight this disease; however, current PRRSV commercially modified-live virus vaccines (MLVs) have the potential to revert to virulence and only provide limited or no cross-protection efficacy against NADC30-like strains. PRRSVs will remain an ongoing challenge to the swine industry until safe and effective vaccines or antiviral reagents are developed.
Project description:Porcine reproductive and respiratory syndrome (PRRS) is one of the most important swine diseases worldwide. In the present study, a new virulent strain of PRRS virus (PRRSV), GDsg, was isolated in Guangdong province, China, and caused high fever, high morbidity, and high mortality in sows and piglets. The genome of this new strain was 15,413 nucleotides (nt) long, and comparative analysis revealed that GDsg shared 82.4% to 94% identity with type 2 PRRSV strains, but only 61.5% identity with type 1 PRRSV Lelystad virus strain. Phylogenetic analysis indicated that type 2 PRRSV isolates include five subgenotypes (I, II, III, IV, and V), which are represented by NADC30, VR-2332, GM2, CH-1a, and HuN4, respectively. Moreover, GDsg belongs to a newly emerging type 2 PRRSV subgenotype III. More interestingly, the newly isolated GDsg strain has multiple discontinuous nt deletions, 131 (19 + 18 + 94) at position 1404-1540 and a 107 nt insertion in the NSP2 region. Most importantly, the GDsg strain was identified as a virus recombined between low pathogenic field strain QYYZ and vaccine strain JXA1-P80. In conclusion, a new independent subgenotype and recombinant PRRSV strain has emerged in China and could be a new threat to the swine industry of China.
Project description:We report the complete genome sequence of a European genotype porcine reproductive and respiratory syndrome virus isolated from swine in northern China in 2012. Genome alignment revealed that the virus (LNEU12) strain shares 90.1% nucleotide identity with the European prototype Lelystad virus. Here, we announce the complete genome sequence of LNEU12.