Microevolution of highly pathogenic avian influenza A(H5N1) viruses isolated from humans, Egypt, 2007-2011

• Published in: Emerging infectious diseases Vol. 19; no. 1; pp. 43 - 50
• Main Authors: Younan, Mary, Poh, Mee Kian, Elassal, Emad, Davis, Todd, Rivailler, Pierre, Balish, Amanda L, Simpson, Natosha, Jones, Joyce, Deyde, Varough, Loughlin, Rosette, Perry, Ije, Gubareva, Larisa, ElBadry, Maha A, Truelove, Shaun, Gaynor, Anne M, Mohareb, Emad, Amin, Magdy, Cornelius, Claire, Pimentel, Guillermo, Earhart, Kenneth, Naguib, Amel, Abdelghani, Ahmed S, Refaey, Samir, Klimov, Alexander I, Donis, Ruben O, Kandeel, Amr
• Format: Journal Article
• Language: English
• Published: United States U.S. National Center for Infectious Diseases 01.01.2013; Centers for Disease Control and Prevention
• Subjects: Animals; Antigens, Viral - immunology; Avian influenza; Avian influenza viruses; Causes of; Chickens - virology; Disease transmission; Egypt; Egypt - epidemiology; Enzyme Assays; evolution; Evolution, Molecular; Genes, Viral; Genetic Drift; genomics; H5N1 avian influenza virus; Health aspects; Hemagglutinin Glycoproteins, Influenza Virus - classification; Hemagglutinin Glycoproteins, Influenza Virus - genetics; highly pathogenic; Humans; Influenza A Virus, H5N1 Subtype - classification; Influenza A Virus, H5N1 Subtype - genetics; Influenza A Virus, H5N1 Subtype - immunology; Influenza A Virus, H5N1 Subtype - pathogenicity; Influenza, Human - epidemiology; Influenza, Human - virology; Neuraminidase - genetics; Phylogeny; poultry; Poultry Diseases - epidemiology; Poultry Diseases - virology; Prevalence studies (Epidemiology); Egypt; United States
• ISSN: 1080-6040; 1080-6059
• DOI: 10.3201/eid1901.121080

We analyzed highly pathogenic avian influenza A(H5N1) viruses isolated from humans infected in Egypt during 2007-2011. All analyzed viruses evolved from the lineage of subtype H5N1 viruses introduced into Egypt in 2006; we found minimal evidence of reassortment and no exotic introductions. The hemagglutinin genes of the viruses from 2011 formed a monophyletic group within clade 2.2.1 that also included human viruses from 2009 and 2010 and contemporary viruses from poultry; this finding is consistent with zoonotic transmission. Although molecular markers suggestive of decreased susceptibility to antiviral drugs were detected sporadically in the neuraminidase and matrix 2 proteins, functional neuraminidase inhibition assays did not identify resistant viruses. No other mutations suggesting a change in the threat to public health were detected in the viral proteomes. However, a comparison of representative subtype H5N1 viruses from 2011 with older subtype H5N1 viruses from Egypt revealed substantial antigenic drift.