Sirisereewan Chaitawat, Woonwong Yonlayong, Arunorat Jirapat, Kedkovid Roongtham, Nedumpun Teerawut, Kesdangsakonwut Sawang, Suradhat Sanipa, Thanawongnuwech Roongroje, Teankum Komkrich
Department of Veterinary Pathology, Faculty of Veterinary Science, Chulalongkorn University, Henri-Dunant Rd., Bangkok, 10330, Thailand.
Department of Farm Resources and Production Medicine, Faculty of Veterinary Medicine, Kasetsart University, Kamphaeng Saen, Nakorn Pathom, Thailand.
Trop Anim Health Prod. 2018 Oct;50(7):1509-1518. doi: 10.1007/s11250-018-1589-4. Epub 2018 Apr 26.
The Chinese highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) has caused a severe threat to the pig population in Southeast Asian countries. The purpose of this study was to investigate the efficacy of a type 2 PRRSV modified live vaccine (PrimePac™ PRRS, lineage 7) against a Thai HP-PRRSV (10PL01, lineage 8). Three-week-old PRRSV-free pigs were randomly assigned into three groups. Vaccinated challenged group (group 1, n = 16) was immunized with PrimePac™ PRRS vaccine at 3 weeks old. The unvaccinated challenged group (group 2, n = 16) was injected with PBS at 3 weeks old, and unvaccinated unchallenged group (group 3, n = 10) was served as a negative control. At 9 weeks old, all groups, except the negative control group, were challenged with the Thai HP-PRRSV. All pigs were monitored daily during 10 days post-infection (dpi) and were necropsied at 10 and 17 dpi. The results revealed that vaccinated challenged pigs showed significantly lower (p < 0.05) mean rectal temperatures, clinical respiratory scores, lung lesion scores, and levels of virus load in serum and lung tissue compared with the unvaccinated challenged pigs. Moreover, vaccinated challenged pigs exhibited PRRSV-specific serum neutralizing antibodies at the end of the experiment. Our findings indicated that the studied type 2 PRRSV vaccine provided partial protection against the Thai HP-PRRSV infection based on the body temperature, levels of viremia, and the severity of lung lesions. These results demonstrated that partial protection of PrimePac™ PRRS vaccine might be useful for controlling HP-PRRSV infection in the endemic area.
中国高致病性猪繁殖与呼吸综合征病毒（HP-PRRSV）对东南亚国家的猪群构成了严重威胁。本研究的目的是调查2型猪繁殖与呼吸综合征病毒（PRRSV）活疫苗（PrimePac™ PRRS，第7谱系）对泰国HP-PRRSV（10PL01，第8谱系）的效力。将3周龄无PRRSV的仔猪随机分为三组。疫苗接种攻毒组（第1组，n = 16）在3周龄时用PrimePac™ PRRS疫苗免疫。未接种攻毒组（第2组，n = 16）在3周龄时注射PBS，未接种未攻毒组（第3组，n = 10）作为阴性对照。在9周龄时，除阴性对照组外，所有组均用泰国HP-PRRSV攻毒。在感染后10天（dpi）内每天监测所有猪，并在10和17 dpi时进行剖检。结果显示，与未接种攻毒的猪相比，接种攻毒的猪的平均直肠温度、临床呼吸评分、肺损伤评分以及血清和肺组织中的病毒载量均显著降低（p < 0.05）。此外，接种攻毒的猪在实验结束时表现出PRRSV特异性血清中和抗体。我们的研究结果表明，基于体温、病毒血症水平和肺损伤严重程度，所研究的2型PRRSV疫苗对泰国HP-PRRSV感染提供了部分保护。这些结果表明，PrimePac™ PRRS疫苗的部分保护作用可能有助于控制流行地区的HP-PRRSV感染。
