School of Preventive Medicine and Public Health, Hanoi Medical University, Vietnam.
Vietnam National Centre for Veterinary Diagnostics, Vietnam.
Biomed Res Int. 2020 Jun 4;2020:1487651. doi: 10.1155/2020/1487651. eCollection 2020.
The spread of avian influenza virus among Asian countries is becoming a concern after influenza epidemics in recent years. This study is aimed at identifying the subtypes of avian influenza viruses collected from healthy chickens and ducks at two live bird markets in a border province of Vietnam and the Lao People Democratic Republic. Cloacal and tracheal swab samples from 100 chickens and 101 ducks were collected in May 2017. All samples were screened to detect avian influenza virus by real-time reverse transcriptase PCR. Samples that are avian influenza virus-positive were isolated in embryonated chicken eggs, and the subtypes were identified by RT-PCR with the specific primers. The samples positive for influenza virus H5 were sequenced to identify HA and NA genes. The prevalence of avian influenza virus (AIV) among chicken and duck samples was 27.5% (55/200) and 24.8% (50/202), respectively. AIV subtypes identified among 17 samples positive with the hemagglutination test include H3N6, H6N6, and H9N2. Of these 17 samples, 7 duck samples were found to be H6N6, 4 duck samples were infected with both subtypes of H3N6 and H6N6, and two chicken samples were recorded as H9N2. A positive chicken sample with A/H5 contains 99% similarity nucleotide with H5N6 reference strain. Results suggested that while the presence of low pathogenic avian influenza virus is predominant, potential risks of the appearance of high pathogen avian influenza virus in the east-west boundary in Vietnam should be concerned and studied further. Furthermore, prevention activities are needed to reduce such biosecurity threats in Vietnam and other Asian countries.
亚洲国家禽流感病毒的传播引起关注，近年来流感疫情不断。本研究旨在鉴定在越南边境省份和老挝人民民主共和国两个活禽市场采集的健康鸡和鸭的禽流感病毒亚型。2017 年 5 月，采集了 100 只鸡和 101 只鸭的泄殖腔和气管拭子样本。所有样本均通过实时逆转录 PCR 筛查以检测禽流感病毒。对禽流感病毒阳性的样本进行鸡胚分离，并使用特异性引物通过 RT-PCR 鉴定亚型。对流感病毒 H5 阳性的样本进行测序以鉴定 HA 和 NA 基因。鸡和鸭样本中禽流感病毒 (AIV) 的流行率分别为 27.5%（55/200）和 24.8%（50/202）。在 17 份血凝试验阳性的样本中鉴定出的 AIV 亚型包括 H3N6、H6N6 和 H9N2。在这 17 份样本中，有 7 份鸭样本为 H6N6，4 份鸭样本同时感染了 H3N6 和 H6N6 两种亚型，2 份鸡样本为 H9N2。一份带有 A/H5 的阳性鸡样本与 H5N6 参考株的核苷酸同源性为 99%。结果表明，虽然低致病性禽流感病毒的存在占主导地位，但越南东西边界高致病性禽流感病毒出现的潜在风险值得关注和进一步研究。此外，需要开展预防活动，以减少越南和其他亚洲国家的此类生物安全威胁。
