Karimi Vahid, Ghalyanchilangeroudi Arash, Hashemzadeh Masoud, Rahimi Forough, Zabihi Petroudi Mohammad Taha, Farahani Reza Kh, Maghsoudloo Hossein, Abdollahi Hamed
1Department of Poultry Diseases, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran.
2Department of Microbiology and Immunology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran.
Virusdisease. 2018 Mar;29(1):123-126. doi: 10.1007/s13337-017-0414-4. Epub 2017 Dec 11.
Infectious bronchitis (IB) is a highly infectious avian pathogen, which affects the respiratory tract, gut, reproductive system, and kidney of chicks of all ages. Many different serotypes of IB virus (IBV) are recognized which cause different clinical manifestations. According to the antigenic differences, different serotypes of the virus do not cross-protect. Massachusetts serotype induces the best cross-protection against other serotypes. Recently, the IBV QX strain has been detected in Iran. QX strain causes permanent damage to the oviduct if it occurs in the early life cycle and is a significant factor in layer and breeder chicken flocks. In this study, we compare the H120 and Ma5 vaccines' protection against early challenge with the QX strain in commercial chicks. one-day-old commercial chicks were divided into six groups. Groups 1 and 2 were unvaccinated groups. Groups 3 and 5 were vaccinated with the H120 vaccine (eye drop) and groups 4 and 6 were vaccinated with Ma5 (eye drop) on the 6th day (5 days after vaccination). Groups 2, 3 and 4 challenged (oculonasal) with QX strain (10^ EID50). Ciliostasis test, histopathology, and quantitative real-time RT-PCR were done at 11 days-old of age. Results showed that neither H120 nor Ma5 could induce proper cross-protection against QX early challenge, but the viral load and adverse pathological records in vaccinated chicks were less than that in the non-vaccinated groups. It can be concluded that vaccination on the first day of the life of a chick offers not full protection against the IBV QX strain but reduced the viral load and pathological damages in vaccinated chickens. Applying other forms of vaccination and using different genotypes on one-day-old chicks are suggested.
传染性支气管炎（IB）是一种高度传染性的禽类病原体，可影响各年龄段雏鸡的呼吸道、肠道、生殖系统和肾脏。已识别出许多不同血清型的传染性支气管炎病毒（IBV），它们会引起不同的临床表现。根据抗原差异，不同血清型的病毒之间不存在交叉保护作用。马萨诸塞州血清型对其他血清型诱导出的交叉保护效果最佳。最近，伊朗检测到了IBV QX株。如果QX株在生命周期早期出现，会对输卵管造成永久性损害，是蛋鸡和种鸡群中的一个重要因素。在本研究中，我们比较了H120和Ma5疫苗对商品雏鸡早期感染QX株的保护作用。1日龄商品雏鸡被分为六组。第1组和第2组为未接种疫苗组。第3组和第5组在第6天（接种疫苗后5天）用H120疫苗（滴眼）接种，第4组和第6组用Ma5（滴眼）接种。第2、3和4组用QX株（10^EID50）进行攻毒（滴鼻点眼）。在11日龄时进行纤毛停滞试验、组织病理学检查和定量实时RT-PCR。结果表明，H120和Ma5均不能对QX早期攻毒诱导出适当的交叉保护作用，但接种疫苗雏鸡的病毒载量和不良病理记录低于未接种疫苗组。可以得出结论，雏鸡出生第一天接种疫苗不能完全保护其免受IBV QX株感染，但可降低接种疫苗鸡的病毒载量和病理损伤。建议在1日龄雏鸡上采用其他形式的疫苗接种并使用不同基因型。
