4. Avian influenza viruses that are —
(a)uncharacterised;
(b)Type A viruses which have an intravenous pathogenicity index in six-week-old chickens of greater than 1.2; or
(c)Type A viruses H5 or H7 subtype for which nucleotide sequencing has demonstrated multiple basic amino acids at the cleavage site of hæmagglutinin