In Egypt, since 2006, descendants of the highly pathogenic avian influenza virus (HP AIV) H5N1 of clade
2.2 continue to cause sharp losses in poultry production and seriously threaten public health. Potentially
zoonotic H9N2 viruses established an endemic status in poultry in Egypt as well and co-circulate with HP
AIV H5N1 rising concerns of reassortments between H9N2 and H5N1 viruses along with an increase of
mixed infections of poultry.
Nucleotide sequences of whole genomes of 15 different isolates (H5N1: 7; H9N2: 8), and of the hemagglutinin
(HA) and neuraminidase (NA) encoding segments of nine further clinical samples (H5N1: 2;
H9N2: 7) from 2013 and 2014 were generated and analysed. The HA of H5N1 viruses clustered with clade
2.2.1 while the H9 HA formed three distinguishable subgroups within cluster B viruses. BEAST analysis
revealed that H9N2 viruses are likely present in Egypt since 2009. Several previously undescribed
substituting mutations putatively associated with host tropism and virulence modulation were detected
in different proteins of the analysed H9N2 and H5N1 viruses.
Reassortment between HP AIV H5N1 and H9N2 is anticipated in Egypt, and timely detection of such
events is of public health concern. As a rapid tool for detection of such reassortants discriminative
SYBR-Green reverse transcription real-time PCR assays (SG-RT-qPCR), targeting the internal genes of
the Egyptian H5N1 and H9N2 viruses were developed for the rapid screening of viral RNAs from both
virus isolates and clinical samples. However, in accordance to Sanger sequencing, no reassortants were
found by SG-RT-qPCR