Molecular detection of PRRSV and variation analysis of ORF5 gene in Fujian province in 2017

Objective  To study the molecular prevalence of the porcine peproductive and respiratory syndrome virus (PRRSV) strain in small and medium-sized pig farms of Fujian province in 2017.

Method  We collected 83 suspected blue ear positive disease materials from small and medium-sized pig farms in Fujian province. RT-PCR detection and genetic evolution analysis of ORF5 gene which encoded GP5 protein was performed.

Result  The positive rate of 83 suspected blue ear disease samples was 73%, and the nucleotide similarity among the measured ORF5sequences was 80.3%−100.0%. The nucleotide similarities between tested strains of different branches and the representative strains of those branches, NADC30, GM2 and JXA1, were 92.6%−93.9%, 89.8%−93.0% and 93.4%−99.3%, respectively. The new identified strain in the new branch had nucleotide similarity of 91.0%−93.0% to JXA1. The GP5 amino acid alignment showed significant variation in functional regions such as GP5 signal peptide region, induction epitope, principal neutralizing epitope and hypervariable region in different subgroups.

Conclusion  A new branch of PRRSV has emerged in Fujian area, making the PRRSV variants in Fujian more diverse. It is necessary to strengthen the monitoring of PRRSV epidemics and mutations.