Table 2. List of substitutions associated with mammalian adaption, drug resistance and virulence, in viral sequences recovered from an infected patient and from environmental samples collected nearby, Inner Mongolia Autonomous region, China, April 2019.

Protein	Mutation	Function	Amino acid	Number of human viruses	Number of environmental viruses
HA	A125Ta	Introduces a glycosylation sequon at 123N and increased avian receptor specificity [10].	A	3	0
			T	3	8
			A/T	2	0
HA	G177Va	Increased virus binding to human-type receptors.	V	8	8
HA	Q217La	Increased virus binding to human-type receptors.	Q	8	8
PB2	K526R	Enhance the 627K and 701N function.	R	8	8
PB2	M535L	M535L and K627E, restored the polymerase activity.	L	8	8
PB2	E627K	Increased virulence in mammalian models.	K	8	0
			E	0	8
PA	K356R	Host signature amino acids (avian to human adaptation resulting in increased replication and pathogenicity in mammals)	R	8	8
PA	S409N	Host signature amino acids (avian to human adaptation resulting in increased replication and pathogenicity in mammals)	N	8	8
M2	A30S	Reduced susceptibility to licensed anti-influenza medications.	S	8	8
M2	S31N	Reduced susceptibility to licensed anti-influenza medications.	N	8	8
NS1	P42S	Altered virulence in mice.	S	8	8
NS1	N205S	Altered antiviral response in host.	S	8	8
NS1	E218stop	Truncation that removes 12 residues from C-terminus with potential effect on pathogenicity [17].	Stop	8	8
NS2	T48A	Altered antiviral response in host.	A	8	8

^a H7 numbering.