Zhou Lei, Yang Beina, Xu Lei, Jin Huan, Ge Xinna, Guo Xin, Han Jun, Yang Hanchun
Key Laboratory of Animal Epidemiology and Zoonosis of Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, People's Republic of China.
Key Laboratory of Animal Epidemiology and Zoonosis of Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, People's Republic of China.
Vet Microbiol. 2017 Aug;207:108-116. doi: 10.1016/j.vetmic.2017.05.031. Epub 2017 Jun 3.
Porcine reproductive and respiratory syndrome reproductive virus is a devastating pathogen causing tremendous economic losses to swine production worldwide. Emergence of novel and variant PRRSV strains always leads to variable protection efficacy of modified-live virus (MLV) vaccines. Prevalence of PRRSV NADC30-like recently emerging in China has brought about clinical outbreaks of the disease. In the present study, the pathogenicity of a NADC30-like strain CHsx1401 for piglets was analyzed, and the potential cross-protective efficacy of three MLV vaccines including two commercial MLV vaccines and an attenuated low pathogenic PRRSV against this virus was further evaluated in piglets. The NADC30-like CHsx1401 was shown to cause fever, respiratory clinical signs, and lung gross and microscopic lesions of the inoculated piglets, suggesting that this virus is moderate virulent for piglets. Vaccination of piglets with the MLV vaccines could not reduce the clinical signs and lung lesions, and was partially efficacious in the reduction of viral loads in sera upon NADC30-like CHsx1401 challenge, indicating that these three MLV vaccines provide extremely limited cross-protection efficacy against the NADC30-like virus infection. Additionally, Ingelvac PRRS MLV appeared to exert some beneficial efficiency in shortening the period of clinical fever and in improving the growth performance of the challenged pigs. Our findings give valuable guidance for the choice and use of PRRSV MLV vaccines to control NADC30-like virus infection in the field.
猪繁殖与呼吸综合征病毒是一种具有毁灭性的病原体，给全球养猪业造成巨大经济损失。新型和变异的猪繁殖与呼吸综合征病毒（PRRSV）毒株的出现总是导致活疫苗（MLV）疫苗的保护效果参差不齐。最近在中国出现的PRRSV NADC30样毒株的流行引发了该病的临床暴发。在本研究中，分析了一株NADC30样毒株CHsx1401对仔猪的致病性，并在仔猪中进一步评估了三种MLV疫苗（包括两种商业MLV疫苗和一种低致病性PRRSV弱毒株）对该病毒的潜在交叉保护效果。结果表明，NADC30样毒株CHsx1401可引起接种仔猪发热、呼吸道临床症状以及肺部大体和微观病变，提示该病毒对仔猪具有中等毒力。用MLV疫苗接种仔猪不能减轻临床症状和肺部病变，在NADC30样毒株CHsx1401攻击后，对降低血清病毒载量有部分效果，表明这三种MLV疫苗对NADC30样病毒感染提供的交叉保护效果极其有限。此外，英特威PRRS MLV似乎在缩短临床发热期和改善受攻击猪的生长性能方面发挥了一些有益作用。我们的研究结果为在实际生产中选择和使用PRRSV MLV疫苗来控制NADC30样病毒感染提供了有价值的指导。
