Table 1. Serum antibody titers and viral detection in the H5N1 HPAI virus-inoculated (group 1) and acute stage contact (group 2) ducks.

	Pre-Inoculation				8 dpi				15 dpi
Bird ID	ELISA	HI-C	HI-H	VN	ELI SA	HI-C	HI-H	VN	ELI SA	HI-C	HI-H	VN	VIa	rRT-PCRb
Group 1
#73	36	<4	<4	<4	107	16	32	<4	104	128	128	128	+	27.8
#75	26	<4	<4	<4	103	8	32	<4	103	64	128	128	+	23.6
#77	34	<4	<4	<4	99	16	64	<4	105	128	128	128	+	26.8
#83	36	<4	<4	<4	101	32	64	<4	99	256	512	128	+	21.6
#92	30	<4	<4	<4	104	16	16	<4	104	128	256	128	+	24.5
Group 2
#71	27	<4	<4	<4	55	<4	<4	<4	63	<4	<4	<4	+	30.5
#84	17	<4	<4	<4	54	<4	<4	<4	104	128	256	16	+	21.5
#85c	37	<4	<4	<4	102	<4	<4	<4	93	4	16	<4	+	24.7
#87	33	<4	<4	<4	68	<4	<4	<4	90	64	128	32	+	26.4
#94c	26	<4	<4	<4	64	<4	<4	<4	nd	nd	nd	nd	+	30.9

Five ducks inoculated with H5N1 HPAI virus (group 1) and five naive contact ducks (group 2) were mixed at one day post inoculation (dpi). Sera were collected at 4 days pre-inoculation for both groups and at 8 and 15 dpi (equivalent to 7 and 14 days post contact (dpc) respectively for group 2). Sera were tested with blocking ELISA (values are % inhibition; cut-off = 60%), HI using chicken RBCs (HI-C) and horse RBCs (HI-H), and virus neutralization (VN) tests. nd: not done.

^a Summary of virus isolation (VI): a+symbol indicates that virus was isolated at least once from either oral or cloacal swab from the duck during the duration of the trial.

^b Summary of Ct values for real-time reverse transcription polymerase chain reaction (rRT-PCR) results: the value is the lowest detected for the duck from either oral or cloacal swabs during the duration of the trial.

^c Ducks 94 and 85 developed disease during the experiment; therefore the last sera were obtained when they were euthanized, for welfare reasons, at 5 dpc (shown under 8 dpi) and 9 dpc (shown under 15 dpi), respectively.