Diagnosis And Comprehensive Control Measures Of PRRSV In Scale Pig Farms

Porcine reproductive and respiratory syndrome virus(PRRSV) is a member of the Arteriviridae family within the order Nidovirales. It is a single-stranded positive-sense RNA viruses which only infects pig. After infected, the virus can cause reproductive disturbance in sows and breath symptom in piglets. PRRSV has transmitted rapidly and became the one of the most serious disease in pig industry since it appeared. Due to the high frequency variation, the vaccine can not always induce enough effective protection in herd, which made protection and control of PRRSV become a global problem.To research comprehensive control measures of PRRSV in present product conditions,our study collected the samples from infected farm in Heyuan of Guangdong province.According the sequence of PRRSV ORF5 from Gen Bank, a pair of primer were designed.Then, the ORF5 gene of virus was amplified by RT-PCR and isolated two PRRSV strains,named HYHC1 and HYHC2. The obtained sequences were both 603 bp and did not exist deletions, sharing 99.2% identity in each other. Both of sequences were belong to North America group when compared with other representation sequence. The phylogenetic tree was builted with MEGA 5.0, and the two PRRSV strains belong to ? subgroup of North America group in the phylogenetic tree. It suggests that the two PRRSV strains in the farm were evolution from the Highly pathogenic strain JXA1 because the high identity in their sequence.This farm has emerged instability PRRSV conditions for a long time and caused large loss in production. Then variants PRRSV vaccine were applied in the hole farm, taken medicine health care on sow herd every quarter, disinfection with pig in rooms, post weaning piglets directly transport into the growth room and better insulation measure were implemented according to the result of the strain analysis to control the epidemic situation.After practice standard management for half year, now the production index has becomeregularly. The antibody titer of PRRSV stays normally and the epidemic situation come to a stable environment.