Serological And Etiological Investigation Of PRRSV In Nanping

Porcine Reproductive and Respiratory Syndrome(PRRS)is also named as "blue ear disease",which is caused by porcine reproductive and respiratory syndrome virus(PRRSV).The PRRSV frequently infect pregnant swines and piglets,it makes great economic losses to pig industry and belong to Class I disease in our country.In order to set up the PRRS defense and control project,the present study will analysis the state of PRRSV infection and immunization in the pig farm of Nanping city in Fujian province.Combined with the PRRSV antibody level and epidemiological investigation,It is helpfμl to provide evidence for PRRS defense and control.During 2014 and 2016,we randomly selected 2040 healthy pigs from 60 large-scale pig farms and 90 free-range farmers,among them,1500 pigs came from large-scale farm and 540 pigs came from free-range farmers.Blood samples were collect from precaval vein,and the serum was prepared for ELISA assay.The ELISA resμlt showed that totally 1845 blood samples(90.4%)were PRRSV positive,among them,1414 blood samples(94.3%)from large-scale farm were positive,while,431 blood samples(79.8%)from free-range farmers were positive.During the period of 2014-2016,the negative rate of PRRSV in each year was 88.7%,90.4%,and 92.2%respectively,present an increase trend as years.At the same time,we extracted mRNA in nasal swab from large-scale pig farms and free-range farmers,and used RT-PCR to detect the PRRSV in nasal swab.The resμlts showed that all samples were PRRSV free.The resμlt shows that there were no PRRSV infection in the large-scale pig farms and free-range farmers,the defense and control PRRSV works well in the area.Taken together,during 2014-2016,the PRRSV antibody negative rate of pig in Nanping city increases gradually,and the PRRSV antibody negative rate in large-scale farm was higher than free-range farmers.At the same time,the entire nasal swab was PRRSV free.These indicated that there were no PRRS infection during 2014 and 2016,immune project were performed better in large-scale farm than free-range farmers.