背景:本领域评估旨在评估新的猪繁殖与呼吸综合征病毒2(PRRSV-2)修饰的活病毒疫苗在三个独立的猪场的功效。
方法:根据断奶后和生长猪的PRRSV-2感染引起的呼吸道疾病状况,选择了三个农场进行本研究。每个农场总共饲养了40只18天大的猪,这些猪被随机分配到两个治疗组之一。根据制造商的建议,在21日龄的猪肌内注射1.0毫升剂量的二价疫苗,而未接种疫苗的猪在相同年龄时给予单剂量磷酸盐缓冲盐水。
结果:与未接种疫苗组相比,所有三个农场的体重和平均日增重均显着(p<0.05)更高。接种组引发PRRS抗体和PRRSV-2特异性干扰素-γ分泌细胞,与未接种疫苗组相比,这减少了血液中PRRSV-2基因组拷贝的量,并降低了宏观和微观肺部病变的严重程度。
结论:现场评估数据表明,一种新的PRRSV-2修饰的活病毒疫苗对患有PRRSV-2感染引起的呼吸道疾病的猪群有效。
BACKGROUND: This field evaluation was designed to evaluate the efficacy of a new porcine reproductive and respiratory syndrome virus-2 (PRRSV-2) modified live virus vaccine at three independent pig farms.
METHODS: Three farms were selected for this study based on their respiratory disease status caused by PRRSV-2 infection in post-weaning and growing pigs. Each farm housed a total of 40, 18-day-old pigs that were randomly allocated to one of two treatment groups. Pigs were administered a 1.0 mL dose of the bivalent vaccine intramuscularly at 21 days of age in accordance with the manufacturer\'s recommendations, whereas unvaccinated pigs were administered a single dose of phosphate buffered saline at the same age.
RESULTS: Vaccinated groups were measured and calculated significantly (p < 0.05) higher in body weight and average daily weight gain on all three farms compared with unvaccinated groups. Vaccinated groups elicited PRRS antibodies and PRRSV-2-specific interferon-γ secreting cells, which reduced the amount of PRRSV-2 genomic copies in the blood and reduced macroscopic and microscopic lung lesions severity when compared with unvaccinated groups.
CONCLUSIONS: The field evaluation data demonstrated that a new PRRSV-2 modified live virus vaccine was efficacious in swine herds suffering from respiratory diseases caused by PRRSV-2 infection.