Southeast Poultry Research Laboratory, Agricultural Research Service, United States Department of Agriculture, 934 College Station Road, Athens, GA 30605, USA.
Virol J. 2013 Jan 30;10:38. doi: 10.1186/1743-422X-10-38.
Avian metapneumovirus subtype C (aMPV/C) causes severe upper respiratory disease in turkeys. Previous report revealed the presence of aMPV/C in wild birds in the southeast regions of the U.S.
In this study, aMPV/C positive oral swabs from American coots (AC) and Canada geese (CG) were passaged three times in the respiratory tract of specific pathogen free (SPF) turkeys and used as aMPV/C P3 virus isolates in subsequent studies.
Wild bird P3 isolates showed similar growth characteristics when compared to virulent aMPV/C in chicken embryo fibroblast ( CEF) cell cultures and their glycoprotein G gene sequence was closely related to the G gene of aMPV/C Colorado reference virus. Three-day-old commercial or SPF turkeys were inoculated oculonasally with wild bird aMPV/C P3 isolates. At 5 and 7 days post-inoculation (DPI), severe clinical signs were observed in both of the AC and CG virus-exposed groups. Viral RNA was detected in tracheal swabs by reverse transcriptase polymerase chain reaction (RT-PCR). In addition, immunohistochemistry showed virus replication in the nasal turbinate and trachea. All virus-exposed turkeys developed positive antibody response by 14 DPI.
Our data demonstrate that aMPV/C wild bird isolates induced typical aMPV/C disease in the domestic turkeys.
禽偏肺病毒 C 亚型（aMPV/C）可导致火鸡发生严重的上呼吸道疾病。先前的报告显示，美国东南部的野生鸟类中存在 aMPV/C。
在这项研究中，从美洲黑鸭（AC）和加拿大鹅（CG）的 aMPV/C 阳性口腔拭子中分离出呼吸道特异型禽偏肺病毒 C（SPF）火鸡，并在随后的研究中作为 aMPV/C P3 病毒分离株进行传代。
与鸡胚成纤维细胞（CEF）中强毒的 aMPV/C 相比，野生鸟类 P3 分离株显示出相似的生长特征，其糖蛋白 G 基因序列与 aMPV/C 科罗拉多参考病毒的 G 基因密切相关。3 日龄商品或 SPF 火鸡经眼鼻接种野生鸟类 aMPV/C P3 分离株。感染后 5 天和 7 天，在 AC 和 CG 病毒暴露组均观察到严重的临床症状。通过逆转录聚合酶链反应（RT-PCR）从气管拭子中检测到病毒 RNA。此外，免疫组织化学显示病毒在鼻甲骨和气管中复制。所有病毒暴露的火鸡在 14 天内均产生了阳性抗体反应。
我们的数据表明，aMPV/C 野生鸟类分离株可在国内火鸡中诱导典型的 aMPV/C 疾病。
