Abstract:RT-PCR and ELISA techniques were used to analyze the prevalence of porcine reproductive and respiratory syndrome in Dali using 4 800 porcine lungs and spleens collected from various districts of Dali as experimental materials.After RNA extraction,concentration detection,reverse transcription,RT-PCR amplification,agarose gel electrophoresis detection,sequencing,and phylogenetic evolution tree analysis of the strains sequences.The results showed that:(1)There were 5 positive samples,while the remaining 4 795 samples were negative,with a positive rate of only 0.104%.(2)Sequencing comparison of the positive samples revealed that they were all highly pathogenic PRRSV infections.(3)After Nsp2 gene sequencing,sequence comparison and phylogenetic tree analysis,all 5 samples belonged to the JXA1 strain.The study found that the prevalent strain of PRRSV in Dali is the JXA1 strain,which is currently well prevented and controlled.Due to the continuous emergence of mutant strains,there is leakage of commercially available commercial testing reagents,and specific testing methods should be established based on molecular epidemiological information to avoid leakage in the monitoring work.In addition,the use of vaccines for prevention and control should be scientifically and rationally selected,and biosecurity measures and regulation of pig introduction and transfer should be strictly done.
