Moatasim Yassmin, Kandeil Ahmed, Mostafa Ahmed, Elghaffar Sary Khaleel Abd, El Shesheny Rabeh, Elwahy Ahmed Helmy M, Ali Mohamed Ahmed
Center of Scientific Excellence for Influenza Viruses, National Research Centre (NRC), El-Behouth Street, Dokki, Giza, 12622, Egypt.
Pathology and Clinical Pathology Department, Faculty of Veterinary Medicine, Assuit University, Assuit, Egypt.
Arch Virol. 2017 Oct;162(10):2959-2969. doi: 10.1007/s00705-017-3434-x. Epub 2017 Jun 15.
Avian influenza A H5N1 and H9N2 viruses have been extensively circulating in various avian species and frequently infect mammals, including humans. The synchronous circulation of both viruses in Egypt provides an opportunity for possible genetic assortment, posing a probable threat to global public health. To assess the potential risk of the IAV reassortants derived from co-circulation of these two AI subtypes, reverse genetics technology was used to generate a set of IAV reassortants carrying single genetic segments of clade 2.2.1.2 virus A/duck/Egypt/Q4596D/2012 (H5N1), a representative of the most prevalent H5N1 clade in Egypt, in the genetic backbone of A/chicken/Egypt/S4456B/2011 (H9N2), a representative of G1-like H9N2 lineage which is widely circulating in Egypt. Furthermore, the genetic compatibility, growth kinetics and virulence were evaluated in vitro in mammalian systems using the MDCK cell line and avian system using SPF embryonated chicken eggs. Pathogenicity and virus shedding were further tested using SPF chickens. Out of the eight desired H9-reassortants, we could rescue only 5 reassortant viruses, either due to difficulty in cloning (PB1 of H5N1 virus) or genetic incompatibility (NP-H5/H9 and NA-H5/H9). Results revealed higher replication rates for the H9N2 virus having the NS segment of H5N1 virus. The lowest survival rate in both SPF eggs and SPF chickens was associated with the H5N1 parent virus infection, followed by the HA-H5/H9 virus. Our findings also suggest that all other reassortant viruses were of lower pathogenicity than the wild type H5N1 virus.
甲型H5N1和H9N2禽流感病毒一直在各种禽类中广泛传播，并经常感染包括人类在内的哺乳动物。这两种病毒在埃及的同步传播为可能的基因重配提供了机会，对全球公共卫生构成了潜在威胁。为了评估这两种禽流感病毒亚型共同传播产生的甲型流感病毒重配体的潜在风险，利用反向遗传学技术构建了一组甲型流感病毒重配体，它们在A/鸡/埃及/S4456B/2011（H9N2）的遗传背景中携带2.2.1.2分支病毒A/鸭/埃及/Q4596D/2012（H5N1）的单个基因片段，A/鸡/埃及/S4456B/2011（H9N2）是在埃及广泛传播的G1样H9N2谱系的代表毒株。此外，利用MDCK细胞系在哺乳动物系统中以及利用SPF鸡胚在禽类系统中对这些重配体的基因兼容性、生长动力学和毒力进行了体外评估。使用SPF鸡进一步检测了致病性和病毒脱落情况。在八个预期的H9重配体中，由于克隆困难（H5N1病毒的PB1）或基因不兼容（NP-H5/H9和NA-H5/H9），我们仅拯救出5种重配病毒。结果显示，具有H5N1病毒NS片段的H9N2病毒复制率更高。在SPF鸡胚和SPF鸡中，最低存活率与H5N1亲本病毒感染有关，其次是HA-H5/H9病毒。我们的研究结果还表明，所有其他重配病毒的致病性均低于野生型H5N1病毒。
