Bwala D G, Abolnik C, van Wyk A, Cornelius E, Bisschop S P R
Poultry Reference Centre, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110 South Africa.
J S Afr Vet Assoc. 2009 Sep;80(3):174-8. doi: 10.4102/jsava.v80i3.197.
Since 2002, following its introduction, the lineage 5d Newcastle disease virus (so-called Goose paramyxovirus - GPMV) strain has caused numerous disease outbreaks among commercial and backyard poultry in South Africa, raising questions about the ability of commercially available Newcastle disease vaccines to fully protect poultry against the strain. This study aimed to determine whether there are differences in the level of protection offered by Avinew Newcastle disease vaccine against GPMV virus as compared with a 3d Newcastle disease virus isolated in South Africa in 1993 (Rainbow challenge virus - RCV) strain. Six groups of 10-day-old, specific pathogen-free chickens were vaccinated with doses of 10(3.0), 10(4.5) and 10(6.0) EID50 of Avinew vaccine and challenged at 4 weeks of age intramuscularly at a dose of 10(5.3) EID50/0.2 ml/bird of GPMV and RCV. No statistically significant difference could be found in the protection offered by Avinew vaccine against GPMV as compared to RCV challenge. The protection offered against the ND challenge was found to be dose dependent. At the recommended field dose of 10(6.0) EID50 the vaccine gave 100% protection from mortality against both the challenge viruses, but not against infection and replication of the viruses, as gross lesions were evident even in apparently healthy birds that survived the challenge. The protective dose (PD90) of the Avinew vaccine against GPMV challenge was calculated at 10(4.38) and against that of RCV at 10(4.43).
自2002年引入以来，5d系新城疫病毒（所谓的鹅副粘病毒 - GPMV）毒株在南非的商业和家庭养殖家禽中引发了众多疾病暴发，这引发了关于市售新城疫疫苗能否完全保护家禽抵御该毒株的疑问。本研究旨在确定与1993年在南非分离的3d新城疫病毒（彩虹挑战病毒 - RCV）毒株相比，Avinew新城疫疫苗对GPMV病毒提供的保护水平是否存在差异。将六组10日龄的无特定病原体鸡分别用10(3.0)、10(4.5)和10(6.0) EID50剂量的Avinew疫苗进行接种，并在4周龄时通过肌肉注射以10(5.3) EID50/0.2 ml/只的剂量用GPMV和RCV进行攻毒。与RCV攻毒相比，在Avinew疫苗对GPMV提供的保护方面未发现统计学上的显著差异。发现对新城疫攻毒提供的保护呈剂量依赖性。在推荐的田间剂量10(6.0) EID50时，该疫苗对两种攻毒病毒的死亡率提供了100%的保护，但对病毒的感染和复制没有保护作用，因为即使在攻毒后存活的看似健康的鸡中也明显出现了肉眼可见病变。Avinew疫苗对GPMV攻毒的保护剂量（PD90）计算为10(4.38)，对RCV攻毒的保护剂量计算为10(4.43)。
