Terregino Calogero, Toffan Anna, Beato Maria Serena, De Nardi Roberta, Vascellari Marta, Meini Amelio, Ortali Giovanni, Mancin Marzia, Capua Ilaria
OIE/FAO and National Reference Laboratory for Newcastle Disease and Avian Influenza, Istituto Zooprofilattico Sperimentale delle Venezie, Viale dell'Universita 10, Legnaro (PD), Italy.
Avian Pathol. 2008 Oct;37(5):487-93. doi: 10.1080/03079450802356938.
The aims of this study were firstly to evaluate the pathogenicity of an Italian isolate of the QX strain of infectious bronchitis (IB) virus using 1-day-old female specific pathogen free chicks (layer type) and 1-day-old female commercial broiler type chickens, and secondly to assess the level of protection induced in these birds by a vaccination programme including the IB Massachusetts and 4/91 serotype live attenuated vaccines. Unvaccinated birds showed clinical signs of varying severity, predominantly affecting the upper respiratory tract. Vaccinated birds appeared healthy, with the exception of a very mild conjunctivitis affecting a limited number of the broilers. Vaccination fully protected specific pathogen free birds, since no histopathological lesions were observed, nor was virus detected following challenge. In broilers, replication of the challenge virus was not prevented but was significantly reduced. This study confirms that vaccination at 1 day old and at 14 days of age using the Ma5 and 4/91 IB vaccines may be instrumental in reducing the economic impact of QX IB virus infections in layer and broiler farms.
本研究的目的，首先是使用1日龄无特定病原体的雌性雏鸡（蛋鸡型）和1日龄雌性商品肉鸡，评估意大利传染性支气管炎（IB）病毒QX株分离株的致病性；其次是评估包括IB Massachusetts和4/91血清型活疫苗的疫苗接种方案对这些鸡所诱导的保护水平。未接种疫苗的鸡表现出不同严重程度的临床症状，主要影响上呼吸道。接种疫苗的鸡除了有少数肉鸡出现非常轻微的结膜炎外，看起来很健康。疫苗接种完全保护了无特定病原体的鸡，因为未观察到组织病理学损伤，攻毒后也未检测到病毒。在肉鸡中，攻毒病毒的复制未被阻止，但显著减少。本研究证实，1日龄和14日龄使用Ma5和4/91 IB疫苗进行接种，可能有助于降低QX IB病毒感染对蛋鸡场和肉鸡场的经济影响。
