. 2010 Jan 21;149(1):86–94. doi: 10.1016/j.virusres.2010.01.006

Table 1.

Clinical signs and virus detection in 2-week-old SPF chickens following treatment with QR448(a) before or after IBV challenge^a.

Treatment	Clinical signs (average score)^b	Virus detection^c	Average Ct value^d	Average histopathology score^e
Intranasal 6 h before challenge	9/10 (2.8)	10/10	23.48	3.32^a
Intranasal 2 h before challenge	6/10 (1.7)	0/10	Neg^f	3.29^a
Intranasal 2 h after challenge	7/10 (1.9)	0/10	Neg	3.58^a

Spray 6 h before challenge	7/10 (1.7)	0/10	Neg	3.28^a
Spray 2 h before challenge	7/10 (1.7)	0/10	Neg	3.32^a
Spray 2 h after challenge	7/10 (1.7)	0/10	Neg	3.24^a

Water 6 h before challenge	10/10 (3.5)	9/10	23.13	3.50^a
Water 2 h before challenge	10/10 (3.2)	10/10	23.31	3.40^a
Water 2 h after challenge	10/10 (3.5)	10/10	24.72	3.39^a

Challenge control^g	10/10 (4.0)	10/10	26.01	3.52^a
Negative control^h	0/10 (1.0)	0/10	Neg	1.06^b

The birds were intranasally challenged with 3.1 × 10⁴ embryo infectious dose₅₀/bird of pathogenic IBV strain Mass41.

Clinical signs were recorded 5 days following challenge and were scored as follows: 1 = normal, 2 = watery eyes or mucus in the nares, 3 = watery eyes and mucus in the nares, and 4 = watery eyes, mucus in the nares and tracheal rales.

Virus was detected directly from tracheal swabs collected 5 days following challenge by real-time RT-PCR.

The average cycle threshold (Ct) value for only the positive samples was calculated and indicates the relative amount of virus detected in the trachea (higher numbers = less virus).

The average histopathology score for only the birds with clinical signs was based on epithelial hyperplasia, lymphocyte infiltration, and epithelial deciliation with 1 being normal and 4 being severe. Numbers with different superscripts are statistically different (Kruskal–Wallis test, p ≤ 0.05).

Negative.

Challenge control birds were not treated and were challenged.

Negative control birds were not treated or challenged.