Cano Jean Paul, Dee Scott A, Murtaugh Michael P, Pijoan Carlos
Swine Disease Eradication Center, University of Minnesota, College of Veterinary Medicine, 385C Animal Science Veterinary Medicine Building, 1988 Fitch Avenue, St. Paul, MN 55108, USA.
Vaccine. 2007 May 30;25(22):4382-91. doi: 10.1016/j.vaccine.2007.03.031. Epub 2007 Apr 3.
The objectives of this study were to evaluate the effects of a therapeutic vaccine intervention with a modified-live porcine reproductive and respiratory syndrome virus (PRRSV) vaccine on the dynamics of a heterologous viral infection in a population of pigs, and to determine the clinical and virological response of previously exposed and vaccinated pigs against a second virulent heterologous challenge. A population of 320 pigs were infected with a field isolate, PRRSV MN-30100, alone or followed by Ingelvac PRRS MLV vaccine administered one to three times at 30 days intervals beginning 1 week after infection. Vaccine intervention reduced the duration of viral shedding, but did not reduce the viral load in tissues or the proportion of persistently infected pigs. A different and highly virulent field isolate, MN-184, was then given as a heterologous viral challenge at 97 days after first exposure. Previously infected and vaccinated pigs showed a significant reduction in clinical signs and enhanced weight gain after the highly virulent challenge with PRRSV MN-184, but infection with and shedding of the challenge isolate were not prevented.
本研究的目的是评估一种用减毒活猪繁殖与呼吸综合征病毒（PRRSV）疫苗进行的治疗性疫苗干预对猪群中异源病毒感染动态的影响，并确定先前暴露和接种疫苗的猪对第二次强毒异源攻击的临床和病毒学反应。320头猪群体单独感染一株田间分离株PRRSV MN - 30100，或在感染1周后开始，每隔30天接种1至3次英特威PRRS MLV疫苗。疫苗干预缩短了病毒排毒持续时间，但未降低组织中的病毒载量或持续感染猪的比例。在首次暴露97天后，用另一株不同的高毒力田间分离株MN - 184进行异源病毒攻击。先前感染并接种疫苗的猪在用PRRSV MN - 184进行高毒力攻击后，临床症状显著减轻，体重增加加快，但未防止感染攻击毒株并出现排毒现象。
