Avian Influenza H5N1 in Egypt: What we Know and What we have to Know?
El-Sayed M. Abdelwhab, Jutta Veits and Thomas C. Mettenleiter
Egypt has experienced endemic outbreaks of avian influenza viruses (AIV) of subtype H5N1 in poultry since 2008. Since then, these viruses continue to evolve. In 2006-2008, outbreaks were reported mostly during the winter season, but in 2009-2012 they occurred year round. H5N1 AIV succeeded in infecting not only domesticated birds but also many other avian species and mammals. Infections of humans were accompanied by mutations in the hemagglutinin (HA) protein which improved the binding affinity to human receptors but simultaneously retained its specificity for avian-receptors. Vaccines were applied nationwide to control the disease in poultry. Meanwhile, the viruses accumulated several point mutations in the HA immunogenic epitopes resulting in antigenic drift and the establishment of infections in vaccinated poultry. The Egyptian H5N1 viruses remain susceptible to oseltamivir, but genetic markers indicating resistance to amantadine have increased dramatically. In this mini-review, we discuss recent findings on the H5N1 viruses endemic in poultry and humans in Egypt, and suggest possible options to control the infection.