03.04.2015

Eurosurveillance, Volume 20, Issue 13, 02 April 2015

In Egypt, highly pathogenic avian influenza (HPAI) influenza A(H5N1) viruses of clade 2.2.1 and their descendants have been circulating in poultry populations since 2006, causing sporadic human infections . Clade 2.2.1 viruses were detected in poultry in Israel and West Bank and Gaza Strip, and in poultry and humans in Egypt. A sharp increase in the number of human cases has been reported in Egypt. The HA proteins of clade 2.2.1 viruses isolated in recent years have continued to evolve and accumulated a number of amino acid substitutions. A distinct cluster of highly pathogenic avian influenza viruses of subtype A(H5N1) has been found to emerge within clade 2.2.1.2 in poultry in Egypt since summer 2014 and appears to have quickly become predominant. Viruses of this cluster may be associated with increased incidence of human influenza A(H5N1) infections in Egypt over the last months.