H5N1亚型禽流感病毒对鹌鹑的致病性及接触传播能力研究

Pathogenicity and contact transmission of H5N1 avian influenza viruses in quails

为研究H5N1亚型禽流感病毒（AIV）对鹌鹑的致病性及其接触传播能力，本研究选择2009年-2012年分离的3株Clade2．3．2病毒株DK／GD／1322／10、DK／GZ／4102／10、GCG／QH／1／09和1株Clade7．2病毒株CK／NX／2／12，以10^5EID50的剂量，人工感染4周龄鹌鹑，并于感染后24h放入同居鹌鹑，检测其发病死亡、排毒、脏器病毒复制、血清抗体转阳情况及其病理组织学变化。结果显示，4株病毒株感染鹌鹑均100％发病和死亡，对鹌鹑的平均致死时间依次为48h、48h、67h和98h，病毒在体内各脏器均能够复制，产生明显的病理组织学变化，并且均能够通过喉头和泄殖腔排毒；DK／GD／1322／10、DK／GZ／4102／10和GCG／QH／1／093株病毒感染组同居鹌鹑分别在6d、4d和3d内全部发病死亡，而CK／NX／2／12病毒株同居组鹌鹑全部存活，血清抗体2／5转阳。以上结果表明，3株Clade2．3．2病毒和1株Clade7．2病毒对鹌鹑均具有高度致死性，但接触传播能力存在一定差异。

To evaluate the pathogenicity and contact transmission of H5N1 subtype avian influenza virus （AIV） in quails, 4-week-old quails were artificially infected with 105 EID50 of 3 AIVs in clade 2.3.2 （DK/GD/1322/10, DK/GZ/4102/10and GCG/QH/1/09） and the AIV in clade 7.2 （CK/NX/2/12）, respectively, which were isolated in China from 2009 to 2012, and the health quails as contact birds were cohabited with artificially infected quails at 24 hours post the inoculation. The pathogenicity was examined by clinical observation, virus isolation, the antibody assay and histopathologic examination. The results showed that all viruses inoculated quails showed systemic infection, shed virus via the oropharynx and cloaca, and died within 48 to 98 hours. In addition, all the cohabited quails infected with the 3 viruses of clade 2.3.2 were dead in 6, 4 and 3 days post cohabitation respectively. However, all the quails cohabited with quails inoculated with the clade 7.2 virus survived without virus shedding, but two of the five quails were antibody-converted. These results indicated that the 3 AIV isolates of clade 2.3.2 and the AIV isolate of clade 7.2 were highly pathogenic to quails, but the abilities for contact transmission were different in quails.