TABLE 3.

Replication and lethality in chickens of the H5N1 viruses after i.n. inoculation^a

Virus	Manifestations of chickens		Virus replication on day 3 p.i. (log10 EID50/g) in:						Virus shedding on day 3 (log10 EID50/ml)
	No. S/D/totalb	No. S.C./totalc	Lung	Brain	Kidney	Spleen	Pancreas	Bursa	Pharyngeal	Cloacal
GS/GD/1/96	0/8/8	/	5.8 ± 0.5	3.8 ± 0.9	4.8 ± 1.7	3.9 ± 0.5	3.9 ± 1.3	5.3 ± 0.7	1.5 ± 1.5	1.3 ± 0.8
GS/GD/2/96	0/0/8	3/8	<0.5	<0.5	<0.5	<0.5	<0.5	<0.5	<0.5	<0.5
R-GS/GD/1/96	0/8/8	/	4.7 ± 1.8	5.3 ± 1.4	5.1 ± 1.2	3.8 ± 1.2	3.4 ± 1.0	5.1 ± 1.2	0.9 ± 0.9	1.0 ± 0.7
R-GS/GD/2/96	0/0/8	2/8	<0.5	<0.5	<0.5	<0.5	<0.5	<0.5	<0.5	<0.5
R-GS/GD/1-2NS	0/0/8	2/8	<0.5	<0.5	<0.5	<0.5	<0.5	<0.5	<0.5	<0.5
R-GS/GD/2-1NS	2/1/8	7/7	1.5 ± 1.7d	1.3 ± 1.3d	0.8 ± 0.4d	<0.5	0.8 ± 0.3	<0.5	0.6 ± 0.2	0.8 ± 0.3

^aThree-week-old SPF chickens were inoculated intranasally (i.n.) with 10⁶ EID₅₀ of each virus in a 0.1-ml volume; on day 3, three birds in each group were killed, and virus titer was determined in samples of lung, bursa, kidney, brain, pancreas, and spleen in eggs. The lower limit of virus detection was 0.5 log₁₀ EID₅₀ per g tissue. The pharyngeal and cloacal swabs were collected from all birds on day 3. <0.5, virus was not detected from that sample.

^bNo. S/D/total shows the number of sick (S) and dead (D) as well as the total number of chickens from the observation period. The birds that showed disease signs, such as depression and ruffled feathers, but recovered at the end of the observation were counted as sick animals.

^cNo. S.C./total shows the number of chickens that seroconverted out of the total number of chickens at the end of the observation period. /, all of the birds died at the end of the observation.

^dP < 0.01 compared with the titers in the corresponding organs of the GS/GD/1/96- or R-GS/GD/1/96-inoculated chickens.