. 2012 Jun;86(12):6924–6931. doi: 10.1128/JVI.07142-11

Table 1.

H5N1 influenza viruses possessing the corresponding HACS^a

Clade	No. of isolates	No. (%) of isolates with HACS
Clade	No. of isolates	GBBBBR↓G^b	IBBBBR↓G^b	RBBBBR↓G^b	-BBBBR↓G^b	SBBBBR↓G^b	Other
0	93	2 (2.2)^c	0	89 (95.7)	2 (2.2)	0	0
1	312	19 (6.1)	0	262 (84.0)	29 (9.3)	0	2 (0.6)
2.1.1	25	0	0	23 (92.0)	1 (4.0)	0	1 (4.0)
2.1.2	34	0	0	34 (100)	0	0	0
2.1.3	106	0	0	22 (20.8)	0	84 (79.2)	0
2.2	384	6 (1.6)	0	376 (97.1)	2 (0.5)	0	0
2.3.1	13	0	0	0	13 (100)	0	0
2.3.2	62	0	0	1 (1.6)	61 (98.4)	0	0
2.3.3	5	0	0	0	5 (100)	0	0
2.3.4	115	0	0	0	115 (100)	0	0
2.4	25	0	0	23 (92.0)	2 (8.0)	0	0
2.5	14	0	0	4 (28.6)	10 (71.4)	0	0
3	30	0	1 (3.3)	29 (96.7)	0	0	0
4	14	0	0	14 (100)	0	0	0
5	23	0	22 (95.7)	0	0	0	1 (4.3)
6	4	0	0	4 (100)	0	0	0
7	14	11 (78.6)	0	1 (7.1)	0	0	2 (14.3)
8	4	0	0	4 (100)	0	0	0
9	26	0	0	26 (100)	0	0	0
Total	1,303	38 (2.9)	23 (1.8)	912 (70.0)	240 (18.4)	84 (6.4)	6 (0.5)

Sequence data were obtained from the Influenza Information Resources of the WHO (http://www.who.int/influenza/resources).

B, basic residue R/K. The sequences of more than 80% of the strains in the P5 to P2 positions were R-R-K-K-.

Number of isolates possessing a specific amino acid at position P6 (proportion of isolates with a specific amino acid at position P6 in the H5N1 virus of the corresponding H5N1 clade in the Influenza Information Resources of the WHO database).