Clinical Experiment Of Highly Pathogenic Porcine Reproductive And Respiratory Syndrome Live Vaccine(JXAI-R) In Hunan Province

Highly pathogenic porcine reproductive and respiratory syndrome (HP-PRRS) is commonly known as highly pathogenic blue-ear disease, which is caused by porcine reproductive and respiratory syndrome virus (PRRSV) and is an acute contagious disease that can only spread among pigs. The main method to prevent and control HP-PRRS is vaccination. However, inactivated vaccines are often difficult to control the epidemic of HP-PRRS in pig farms, some regions have started to vaccinate with the HP-PRRS attenuated vaccine (live vaccine).In order to test the immune effects of HP-PRRS attenuated vaccine, we selected four pig farms in Hunan province and vaccinated them with JXA1_R strain live vaccine. The mainly completed work is as followings:1. Before vaccination, we investigated and monitored the background as well as immunization situation of the pig farms. The results showed that four pig farms had been vaccinated with the PRRS vaccine, and the antibody positive rate of PRRSV was from9.1percent to52.2percent after tested by the kit from LSI Corporation, but the antibody positive rate were zero after tested by the kit from IDEXX Corporation.2. The safety of the attenuated live vaccine (JXA1-R strain) is reliable by observing the health status and Clinical response of the participant experiment pigs after vaccination.3. Monitoring the antibody levels of the collected blood samples with ELISA, the results demonstrated that the antibody positive rate of PRRSV was from75.0percent to95.2percent after tested by the kit from LSI Corporation, at the same time it was from90percent to100percent after tested by the kit from IDEXX Corporation. And the antibody positive rate was from81percent to100percent after tested by the kit from LSI Corporation but was from91percent to100percent after tested by the kit from IDEXX Corporation at60days after immunization.90days after immunization, its levels was from91percent to100percent after tested by the kit from LSI Corporation, meanwhile it was100percent after tested by the kit from IDEXX Corporation.4. Detecting the vaccine virus by real time RT-PCR, all porcine serum samples were negative at60days and90days after vaccinating with the attenuated live vaccine.In conclusion, the immune effects of different batches of live vaccine from four vaccine manufacturers is reliable, which showed that the HP-PRRS attenuated live vaccine (JXA1-R strain) is of good stability.