Table 2. Selection of H5N1 viruses in individual ducks as demonstrated by HI assay.

		HI titer
		Postinfection polyclonal antisera				mAb to H5 HA (A/ck/PA/83)
Virus inoculated	Day isolated	A/HK/156/97	A/gs/HK/437-4/99	A/ck/VN/c58/04	Homologous virus†	CP24	CP58	176/26	406/7
A/mallard/Vietnam/16D/03	0*	640	160	<40	160	400	300	200	300
	7	640	320	<40	320	400	400	<100	300
	11	<40	80	<40	160	400	100	<100	100
	17	40	80	160	<40	400	<100	300	100
A/Vietnam/3046/04 (human isolate)	0*	1,280	1,280	2,560	320	500	400	<100	400
	11	1,280	<40	160	160	<100	<100	<100	<100
	13	1,280	40	320	80	<100	100	<100	<100
A/chicken/Vietnam/48C/04	0*	320	160	160	80	400	800	<100	300
	7	320	160	160	40	400	800	<100	300
	11	<40	<40	80	40	<100	<100	<100	100
	17	<40	<40	160	<40	<100	<100	<100	<100
A/chicken/Pangkal	0*	<40	160	40	40	<100	<100	<100	<100
Pinang/BPPV3/04	11	<40	80	80	80	<100	<100	<100	<100

^*Refers to the original virus.

^†Sera obtained from mallard ducks on day 17 after inoculation.