Role of Poultry in the Spread of Novel H7N9 Influenza Virus in China
Role of Poultry in the Spread of Novel H7N9 Influenza Virus in China
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DOI：
10.1128/jvi.03689-13
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发表时间：
2014-05-01
影响因子：
5.4
通讯作者：
Suarez, David L.
中科院分区：
文献类型：
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作者：
Pantin-Jackwood, Mary J.;Miller, Patti J.;Suarez, David L.
中国最近爆发的H7N9流感导致多例人类感染病例，病死率高。根据序列分析和从活禽市场分离出的病毒，家禽可能是人类的感染源，但目前尚不清楚哪种鸟类最有可能被感染，以及病毒脱落程度足以感染人类。鸡、日本鹌鹑、鸽子、北京鸭、绿头鸭、麝鸭和雏鹅经鼻接种A/Anhui/1/2013病毒10650%蛋感染剂量后感染，但无临床疾病症状。鹌鹑和鸡的病毒脱落比其他物种要高得多，时间也长得多。鹌鹑有效地将病毒传播给直接接触者，但鸽子和北京鸭没有。在所有物种中，从口咽拭子中检测到的病毒滴度远高于从肛肠拭子中检测到的病毒滴度。选取实验感染禽类标本进行血凝素基因测序，与A/Anhui/1/2013序列比较，发现有3个氨基酸差异：N123D、N149D和L217Q。217位亮氨酸在人类分离物中高度保守，与α 2,6-唾液酸结合有关。观察到不同的氨基酸组合，表明接种物具有病毒亚群，这些亚群是在鸟类传代后选择的。这些实验研究证实了某些家禽物种是H7N9流感病毒的宿主，并且该病毒对上呼吸道具有高度亲和性，因此对鸟类物种的检测应优先使用口咽拭子进行，以获得最佳灵敏度。
The recent outbreak of H7N9 influenza in China has resulted in many human cases with a high fatality rate. Poultry are the likely source of infection for humans on the basis of sequence analysis and virus isolations from live bird markets, but it is not clear which species of birds are most likely to be infected and shedding levels of virus sufficient to infect humans. Intranasal inoculation of chickens, Japanese quail, pigeons, Pekin ducks, Mallard ducks, Muscovy ducks, and Embden geese with 106 50% egg infective doses of the A/Anhui/1/2013 virus resulted in infection but no clinical disease signs. Virus shedding was much higher and prolonged in quail and chickens than in the other species. Quail effectively transmitted the virus to direct contacts, but pigeons and Pekin ducks did not. In all species, virus was detected at much higher titers from oropharyngeal swabs than cloacal swabs. The hemagglutinin gene from samples collected from selected experimentally infected birds was sequenced, and three amino acid differences were commonly observed when the sequence was compared to the sequence of A/Anhui/1/2013: N123D, N149D, and L217Q. Leucine at position 217 is highly conserved for human isolates and is associated with alpha 2,6-sialic acid binding. Different amino acid combinations were observed, suggesting that the inoculum had viral subpopulations that were selected after passage in birds. These experimental studies corroborate the finding that certain poultry species are reservoirs of the H7N9 influenza virus and that the virus is highly tropic for the upper respiratory tract, so testing of bird species should preferentially be conducted with oropharyngeal swabs for the best sensitivity.