Table 1.

Number of birds with gross lesions and mean lesion scores at necropsy.

Lesions	Groupa	Days of sampling (post-inoculation)
		3	5	7	10	15	Cumulative total
Trachea	YN	1b (1.5)c	2 (2.0)	2 (2.0)	2 (2.0)	2 (2.0)	9 (1.9)
	aYN	2 (2.0)	0 (0)	1 (0.5)	0 (0)	2 (1.0)	5 (0.7)**
Proventriculus	YN	1 (0.5)	1 (0.5)	2 (1.0)	2 (2.0)	0 (0)	6 (0.8)
	aYN	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)**
Duodenum	YN	2 (1.5)	1 (1.5)	2 (1.0)	1 (1.0)	1 (1.0)	7 (1.2)
	aYN	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)**
Bursa of Fabricius	YN	0 (0)	1 (0.5)	2 (2.0)	2 (3.0)	2 (2.0)	7 (1.5)
	aYN	0 (0)	0 (0)	1 (0.5)	0 (0)	1 (0.5)	2 (0.2)**
Lung	YN	2 (2.0)	2 (2.0)	1 (1.5)	2 (2.0)	2 (1.5)	9 (1.8)
	aYN	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)***
Kidney	YN	2 (2.0)	1 (1.5)	2 (3.0)	2 (3.0)	2 (2.0)	9 (2.3)
	aYN	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)***

The significance was considered as follows: significant at P≤0.05 (*), highly significant at P ≤ 0.01 (**), and very highly significant at P ≤ 0.001 (***).

^aYN group infected with YN strain; aYN group infected with attenuated YN strain. There were no lesions in birds in the control group.

^bNo. of birds with lesions out of two birds.

^cMean lesion scores out of two birds.