Zhang Chuanmei, Xuan Yang, Shan Hu, Yang Haiyan, Wang Jianlin, Wang Ke, Li Guimei, Qiao Jian
Department of Pathophysiology, College of Veterinary Medicine, China Agricultural University, Beijing, 100094, China.
College of Animal Science and Veterinary Medicine, Qingdao Agricultural University, Qingdao, 266109, China.
Virol J. 2015 Nov 2;12:180. doi: 10.1186/s12985-015-0411-4.
The prevalence of avian H9N2 viruses throughout Asia, along with their demonstrated ability to infect mammals, puts them high on the list of influenza viruses with pandemic potential for humans. In this study, we investigated whether H9N2 viruses could infect farmed minks.
First, we conducted a serological survey for avian influenza virus antibodies on a random sample of the field-trial population of farmed minks. Then we inoculated farmed minks with A/Chicken/Hebei/4/2008 H9N2 viruses and observed the potential pathogenicity of H9N2 virus and virus shedding in infected minks.
H9 influenza antibodies could be detected in most farmed minks with a higher seropositivity, which indicated that farmed minks had the high prevalence of exposure to H9 viruses. After infection, the minks displayed the slight clinical signs including lethargy and initial weight loss. The infected lungs showed the mild diffuse pneumonia with thickened alveolar walls and inflammatory cellular infiltration. Influenza virus detection showed that viruses were detected in the allantoic fluids inoculated supernatant of lung tissues at 3 and 7 days post-infection (dpi), and found in the nasal swabs of H9N2-infected minks at 3-11 dpi, suggesting that H9N2 viruses replicated in the respiratory organ, were then shed outwards. HI antibody test showed that antibody levels began to rise at 7 dpi.
Our data provided the serological and experimental evidences that strongly suggested farmed minks under the natural state were susceptible to H9N2 viral infection and might be the H9N2 virus carriers. It is imperative to strengthen the H9N2 viral monitoring in farmed minks and pay urgent attention to prevent and control new influenza viruses pandemic prevalence.
H9N2禽流感病毒在亚洲广泛流行，且已证实其具有感染哺乳动物的能力，这使其成为具有人类大流行潜力的流感病毒中的重点关注对象。在本研究中，我们调查了H9N2病毒是否能感染养殖水貂。
首先，我们对养殖水貂的田间试验群体进行随机抽样，开展禽流感病毒抗体的血清学调查。然后，我们用A/Chicken/Hebei/4/2008 H9N2病毒接种养殖水貂，观察H9N2病毒在感染水貂中的潜在致病性和病毒排泄情况。
在大多数养殖水貂中可检测到H9流感抗体，血清阳性率较高，这表明养殖水貂接触H9病毒的患病率较高。感染后，水貂表现出轻微的临床症状，包括嗜睡和初期体重减轻。受感染的肺部显示出轻度弥漫性肺炎，肺泡壁增厚，有炎性细胞浸润。流感病毒检测显示，在感染后3天和7天（dpi），在接种肺组织上清液的尿囊液中检测到病毒，在感染H9N2的水貂的鼻拭子中在3 - 11 dpi时发现病毒，这表明H9N2病毒在呼吸器官中复制，然后向外排泄。血凝抑制（HI）抗体试验表明，抗体水平在7 dpi时开始上升。
我们的数据提供了血清学和实验证据，有力地表明自然状态下的养殖水貂易受H9N2病毒感染，可能是H9N2病毒携带者。必须加强对养殖水貂的H9N2病毒监测，并紧急关注预防和控制新型流感病毒的大流行。
