Novel genetic reassortants in H9N2 influenza A viruses and their diverse pathogenicity to mice

Table 3 Differences in pathogenicity among the H9N2 AIVs to BALB/c mice

Virus	Virus replication in mouse lung at 3 d.p.i. (log₁₀EID₅₀/0.1ml)	Clinical syndromes		Seroconversion (HI mean titer)
		Body weight (%)^c	Fur
Ck/SD/BD/08	1/3 (<^a)	gain (16.27)	unruffled	< 10
Ck/SD/KD/09	1/3 (<^a)	gain (12.86)	unruffled	20-160
Ck/SD/BD/10	1/3 (<^a)	gain (13.97)	unruffled	40-320
Ck/SD/03/10	-^b	gain (13.82)	unruffled	10-20
Ck/SD/02/09	2/3 (1.5, 2.75)*	gain (10.55)	unruffled	160-320
Ck/HLJ/u/98	3/3 (2.5, 3.75, 2.5)**	lose (14.72)	ruffled	< 10
Ck/SD/LY-1/08	3/3 (5.0, 5.5, 5.25)**	lose (6.09)	Little ruffled	20-40
Ck/SD/WF/98	3/3 (1.5, 2.75, 2.0)**	lose (14.77)	ruffled	40-80
Mock-infected control	-	gain (13.04)	unruffled	-

^a <, Virus titer < 1 log₁₀EID₅₀.
^b -, No virus or haemagglutination inhibition (HI) titer was detected.
^c The percentage of the mean maximum weight loss or gain among the inoculated mice over the course of infection.
* The data were compared with the Ck/SD/BD/08 group by 2-way ANOVA, respectively, *P < 0.01, **P < 0.001.

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