Table 1.

Mortality, serology, and quantitative RT-PCR analysis of viral shedding in White Leghorn chickens challenged with A/VN/1203/04 or NDV Fontana at three weeks of age following in-ovo vaccination.

Vaccine group	Challenge virus	Mortality (MDT)a	Serologyb				Quantitative RRT-PCR analysis
			21 DPH		14 DPC		Positive samples		Mean virus titre/mL (S.D.)c
			AIV	B1	AIV	B1	oral	cloacal	Oral	cloacal
sham	AIV	10/10 (1.6)	0/10	0/10	NA	NA	10/10	10/10	7.6 (0.5)	7.4 (0.5)
VN/HN	AIV	2/10 (2.5)	3/10 (6)	7/10 (32)	8/8 (30)	7/8 (56)	3/10	1/10	≤4.1 (1.5)d	≤4.9 (1.0)d
sham	NDV	10/10 (5.7)	0/10	0/10	NA	NA	10/10	8/10	6.0 (0.5)	≤4.9 (0.7)
VN/HN	NDV	1/10 (6.0)	3/10 (7)	8/10 (24)	7/9 (11)	9/9 (891)	8/10	0/10	≤5.1 (0.7)	≤4.0 (0)e

^aMDT, mean death time in days. All birds displaying clinical signs (morbidity) died.

^bHemagglutination inhibition assay performed 21 days post-hatch (DPH) and 14 days post-challenge (DPC). The proportion of positive birds is indicated, with the geometric mean titres in parentheses.

^cTitres calculated from quantitative RRT-PCR standard curve and expressed as log₁₀EID₅₀/mL. Unless otherwise indicated, the mean and median titres for each group did not differ by more than 10^0.2 EID₅₀/mL.

^dBecause most of the RRT-PCR samples were negative, the median titres/mL were equal to the values assigned to the negative AIV samples (3.3 for oral swabs and 4.6 for cloacal swabs).

^e4.0 is the titre/mL value assigned to negative RRT-PCR NDV cloacal swabs.