Arafa Abdel-Satar, Hagag Naglaa M, Yehia Nahed, Zanaty Aly M, Naguib Mahmoud M, Nasef Soad A
National Laboratory for Veterinary Quality Control on Poultry Production, Animal Health Research Institute, P.O. Box 264-Dokki, Giza-12618, Egypt.
Avian Dis. 2012 Dec;56(4 Suppl):849-57. doi: 10.1637/10152-040812-Reg.1.
Widespread prevalence of avian influenza H9N2 subtype in the Middle East region and its detection in Egypt in quail in early summer 2011 added another risk factor to the Egyptian poultry industry in addition to highly pathogenic H5N1 subtype. This situation increases the need for further surveillance and investigation of H9N2 viruses in commercial and household chickens. This work describes detection and genetic characterization of recently isolated H9N2 viruses from chicken flocks. Parallel detection and genetic characterization of H5N1 viruses from infections in poultry has also been done to compare the prevalence of the two subtypes in close geographic locations in Egypt. Phylogenetic analysis of the HA gene showed that the Egyptian isolates of H9N2 were grouped together within the quail/Hong Kong/G1/97-like lineage, similar to the circulating viruses in the Middle East, with very close phylogeny to the Israeli viruses. The prevalence of H5N1 viruses from cases recorded in poultry in the nearby areas revealed a marked decrease in disease incidence in commercial broilers but an increased incidence in household birds. The genetic characterization of the H5N1 viruses indicated predominance of the classic 2.2.1 subclade, with evolution of new viruses and no detection for the variant 2.2.1.1 subclade. The cocirculation of the two subtypes, H5N1 and H9N2, of avian influenza may affect the limit of spread and the epizootiologic pattern of the infections for both subtypes, especially when different vaccination and biosecurity approaches are applied in the field level.
中东地区H9N2亚型禽流感广泛流行，且于2011年初夏在埃及鹌鹑中被检测到，这给埃及家禽业增添了另一个风险因素，此外还有高致病性H5N1亚型。这种情况增加了对商业和家庭养鸡中H9N2病毒进行进一步监测和调查的必要性。这项工作描述了最近从鸡群中分离出的H9N2病毒的检测和基因特征。还对家禽感染的H5N1病毒进行了平行检测和基因特征分析，以比较这两种亚型在埃及相近地理位置的流行情况。对HA基因的系统发育分析表明，埃及的H9N2分离株聚集在鹌鹑/香港/G1/97样谱系中，与中东地区正在传播的病毒相似，与以色列病毒的系统发育关系非常密切。附近地区家禽记录病例中H5N1病毒的流行情况显示，商业肉鸡的疾病发病率显著下降，但家庭饲养禽类的发病率有所上升。H5N1病毒的基因特征表明，经典的2.2.1亚分支占主导地位，有新病毒进化，未检测到变异的2.2.1.1亚分支。禽流感H5N1和H9N2两种亚型的共同流行可能会影响这两种亚型感染的传播范围和流行模式，尤其是在田间应用不同的疫苗接种和生物安全措施时。
