b) For all H5 and H7 viruses of low pathogenicity in chickens, the amino acid sequence of the
connecting peptide of the haemagglutinin must be determined. If the sequence is similar to
that observed for other HPAI isolates, the isolate being tested will be considered to be
HPAI (see the table that lists all the reported haemagglutinin proteolytic cleavage site of
HA0 protein for H5 and H7 LPAI and HPAI viruses based on deduced amino acid sequence,
which can be found on the OFFLU site at:
http://www.offlu.net/fileadmin/home/en/resource-centre/pdf/Influenza_A_Cleavage_Sites.pdf.
The OIE has the following classification system to identify influenza A viruses for which disease
reporting and control measures should be taken:
a) All influenza A isolates from poultry that meet the above criteria are designated as HPAI and are
notifiable