OIE/FAO Reference Laboratory for Newcastle Disease and Avian Influenza, Department of Comparative Biomedical Sciences, Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro, Padova, Italy.
Vet Microbiol. 2013 Jul 26;165(1-2):177-83. doi: 10.1016/j.vetmic.2013.03.014. Epub 2013 Mar 25.
Avian influenza viruses of the H9N2 subtype have circulated in the poultry population in Asia, Far and Middle East since the mid-1990 s. One of the most widespread lineages established in poultry is the G1 lineage. This lineage has undergone further evolution and reassortment since its first detection in 1997 and G1-like H9N2 viruses still circulate. In this study we have investigated the susceptibility of quail and turkeys to the H9N2 G1-lineage prototype strain (A/quail/Hong Kong/G1/97). Contact transmission experiments were carried out in both avian species. Animals were infected oro-nasally with increasing doses of the virus (10(3)-10(6) EID 50/0.1 ml) and sentinel birds were introduced 4 days post infection (pi) in each experimental group. Quail were more susceptible than turkeys, as they were readily infected with lower challenge doses. Interestingly, infection of turkeys was associated with worse clinical condition. Transmission was detected in both species. Quail infected with a dose less than or equal to 10(4) EID50 transmitted the virus to the sentinels without showing any signs of disease. These findings reinforce the hypothesis that quail may ensure the perpetuation of H9N2 viruses in poultry, acting as a silent reservoir.
自 20 世纪 90 年代中期以来，H9N2 亚型禽流感病毒就在亚洲、远东和中东的家禽中传播。在禽类中建立的最广泛的谱系之一是 G1 谱系。自 1997 年首次检测到该谱系以来，该谱系经历了进一步的进化和重配，并且仍然存在 G1 样 H9N2 病毒。在这项研究中，我们研究了鹌鹑和火鸡对 H9N2 G1 谱系原型株（A/quail/Hong Kong/G1/97）的易感性。在这两个禽类物种中进行了接触传播实验。动物经口鼻感染递增剂量的病毒（10(3)-10(6) EID 50/0.1 ml），并且在每组感染后 4 天引入哨兵鸟。鹌鹑比火鸡更易感，因为它们可以用较低的挑战剂量轻易感染。有趣的是，火鸡的感染与更严重的临床状况有关。在这两个物种中均检测到了传播。感染剂量低于或等于 10(4) EID50 的鹌鹑将病毒传播给哨兵鸟，而没有表现出任何疾病迹象。这些发现强化了鹌鹑可能在禽类中确保 H9N2 病毒持续存在的假设，充当了沉默的储存库。
