Table 2 Analyses of virulence in ovo, in vivo and substituting mutations in HA and NA glycoproteins described to increase virulence of H9Nx strains in the chicken host [19]

BD_11749

H9N2

PAKSKR

Tribasic

20

0

A

L

E

M

BD_11758

N/D

N/D

A

L

Q

M

BD_11760

N/D

N/D

A

L

E

M

BD_11787

N/D

N/D

A

Q

E

M

IN_117

20

N/D

A

L

E

M

IN_3535

N/D

N/D

A

L

Q

M

IN_118

H9N2

PARSSR

Dibasic-1

17

0

A

L

E

M

IN_119

N/D

N/D

A

L

E

M

IN_3532

N/D

N/D

A

L

E

M

IN_3533

N/D

N/D

A

L

E

M

EG_536

17

N/D

A

L

E

M

BD_VP01

H9N2

PAKSSR

Dibasic-2

8

0

A

L

E

M

BD_3534

N/D

N/D

A

L

E

M

DU_120

H9N2

QARSSR

Dibasic-3

N/D

N/D

A

Q

E

M

DU_121

H9N2

HARSSR

Dibasic-4

2

N/D

T

L

E

M

MO_166

2

0

T

R

E

M

SA_1885

N/D

N/D

T

L

E

M

DE_3280

H9N2

PAASKR

Dibasic-5

N/D

N/D

E

Q

E

M

DE_234

H9N2

PAASNR

Monobasic-1

2

N/D

E

Q

E

M

DE_143

H9N3

N/D

N/D

E

Q

E

N/A

DE_144

H9N3

N/D

N/D

E

Q

E

N/A

DE_142

H9N8

PAASSR

Monobasic-2

2

0

E

Q

E

N/A

Mock^b

N/A

N/A

N/A

0

N/A

N/A

N/A

N/A

N/A