Davison S, Smith G, Eckroade R J
Laboratory of Avian Medicine and Pathology, New Bolton Center, University of Pennsylvania, School of Veterinary Medicine, Kennett Square 19348.
Avian Dis. 1989 Jan-Mar;33(1):24-9.
Challenge studies using the standard National Veterinary Services Laboratory laryngotracheitis (LT) challenge virus (Log 10(6.7) EID50 per ml) were conducted to assess the presence of maternal protection in chicks of various ages (1, 7, 14, 21, and 28 days). Chicks from vaccinated and unvaccinated breeders were challenged by intratracheal inoculation. Chicks of all these ages irrespective of origin were susceptible to infection. Similarly derived chicks were vaccinated by eyedrop with a commercially available tissue-culture vaccine. Chicks vaccinated at 21 and 28 days were adequately protected from challenge (77-94% protection), whereas less than 60% of chicks vaccinated at 1, 7, or 14 days were protected.
采用标准的国家兽医服务实验室喉气管炎（LT）攻毒病毒（每毫升10的6.7次方EID50）进行攻毒试验，以评估不同日龄（1、7、14、21和28日龄）雏鸡的母源保护情况。对来自接种疫苗和未接种疫苗种鸡的雏鸡进行气管内接种攻毒。所有这些日龄的雏鸡，无论来源如何，均易感染。同样来源的雏鸡通过滴眼接种市售组织培养疫苗。21日龄和28日龄接种疫苗的雏鸡受到充分保护，免受攻毒（保护率为77%-94%），而1日龄、7日龄或14日龄接种疫苗的雏鸡，受保护的比例不到60%。
