Table 4. Mammalian adaptation–related molecular markers of the human and nonhuman A(H5N6) viruses, China.

Protein	Biologic effect	Mutations	Amino acids	Human viruses	Nonhuman viruses
HA*	Altered receptor specificity	T192I	T	22	1,238
			A	2	24
			I	18	36
			K	0	2
	Altered receptor specificity	Q226L	Q	39	1,302
			L	2	0
			Q\R	1	0
	Altered receptor specificity	S2227N/R	S	6	136
			G	3	31
			H	1	2
			H/R	2	0
			Q	0	92
			R	30	1,036
			C	0	4
	Altered receptor specificity	G228S	G	42	1,302
NA†	Reduced susceptibility to neuraminidase inhibitors	E119V/A/D	E	41	1,253
			D	1	34
			G	0	1
M2	Reduced susceptibility to amantadine	V27A	V	41	1,154
			A	1	20
			G	0	9
			I	0	15
	Reduced susceptibility to amantadine	A30V/T/S	A	41	1,197
			A/T	1	0
			S	0	1
	Reduced susceptibility to amantadine	S31N/G	S	33	994
			N	9	204
PA	Reduced susceptibility to endonuclease inhibitors	I38M/T/S/L	I	39	1,181
			L	0	1
			M	0	1
			V	1	1
PB2	Increased virulence in mammalian models	Q591K	Q	40	1,194
			K	1	0
	Increased virulence in mammalian models	E627K	E	28	1,180
			K	12	3
			E/V	1	1
			V	0	9
	Increased virulence in mammalian models	D701N	D	36	1,193
			D/N	1	0
			N	4	0
NS1	Altered virulence in mice	D92E	D	18	185
			E	24	1,011
			G	0	1
	Altered virulence in mice	L103F	L	8	165
			F	26	1,020
			S	0	11
			V	7	1
			Y	1	0
	Altered virulence in mice	I106M	I	8	166
			K	0	4
			M	34	1,027
M1	Altered virulence in mice	N30D	D	42	1,200
	Impacts growth and transmission in the guinea pig	P41A	A	42	1,199
			S	0	1
	Altered virulence in mice	T139A	T	40	1,113
			A	2	58
			P	0	29
	Altered virulence in mice	T215A	A	42	1,200

*H3 numbering system was used. †N2 numbering system was used.