Table 1.

Lethality of WT and airborne-transmissible A/H5N1 virus in ferrets upon inoculation via different routes. n, number of animals; N.A., not applicable.

Inoculation route	Virus	Dead or moribund (no. dead/no. tested)	Day of death postinoculation (no.)
Intratracheal	A/H5N1wildtype	6/6*	2 (n = 2), 3 (n = 4)
	A/H5N1/F5	6/6	3 (n = 6)
Intranasal	A/H5N1wildtype/P10	2/2†	6 (n = 2)
	A/H5N1HA Q222L,G224S PB2 E627K/P10	0/4	N.A.
	A/H5N1/F2	0/2	N.A.
	A/H5N1/F5	1/2	6 (n = 1)
Airborne	A/H5N1wildtype	N.A.	N.A.
	A/H5N1HA Q222L,G224S PB2 E627K/P10	0/3	N.A.
	A/H5N1/F2	0/2	N.A.
	A/H5N1/F5	0/1	N.A.

^*These data refer to a published study (45).

^†These ferrets were inoculated with P10 H5N1wildtype virus, but data are consistent with previous studies that used larger groups of animals inoculated with the original strain (39, 40).