TABLE 6.

Summary of histopathological lesions in lung, trachea, spleen, intestine, and brain from chickens infected with N, P, L, and trailer sequence chimeras of NDV strains BC and GBT^a

Tissue and histopathological lesion	Control		rBC		rBC-GBT(N)		rBC-GBT(P)		rBC-GBT(L)		rBC-GBT(N+P+L)		rBC-GBT (Tr)		rGBT		rGBT-BC(N)		rGBT-BC(P)		rGBT-BC(L)		rGBT-BC(N+P+L)		rGBT-BC(Tr)
	S	D	S	D	S	D	S	D	S	D	S	D	S	D	S	D	S	D	S	D	S	D	S	D	S	D
Lung
Bronchial lymphoid aggregates	1	1	0	0	1*	1*	1–2	2	1*	1*	2*	2*	1–3	2	2*	2*	1*	2*	0	0	2–3	2	3*	2*	1*	2*
Lymphocytic parabronchitis	1	1	1	2	1	2	1	2	1–2	2	1	2	1–2	2	1–2	2	2	2	1–2	2	2	2	1	2	1	2
Alveolar duct epithelial hyperplasia	0	0	1	2	1	2	1	2	0	0	1	2	1	2	1	2	1*	2*	0	0	0	0	0	0	0	0
Trachea
Lymphocytic tracheitis	0	0	0	0	0	0	2*	1*	1–3*	1–2*	1*	1*	1	2	1*	2*	2*	2*	1–2	2	0	0	1*	1*	1	2
Mucosal attenuation	0	0	2	2	1	2	0	0	0	0	3*	2*	0	0	1–3	2	0	0	1*	2*	0	0	0	0	0	0
Necrotic/apoptotic mucosal cells	−		−		−		−		−		+		−		+		−		−		−		−		+
Spleen
Lymphoid hyperplasia	0	0	3	5	3–4	5	3	5	3	5	3–4	5	3	5	4	5	3	5	3	5	3–4	5	3–4	5	3	5
Intestine
Lymphocytic enteritis	0	0	2–4	1–3	2*	1*	1*	1*	2*	2*	2*	2*	1*	2*	1*	2*	0	0	1–2*	2*	2*	2*	0	0	1	2
Mucosal hyperplasia	0	0	2–3	2	2–3	2	2	2	2–3	2	3	2	2*	2*	2	2	1–2	2	1–2	2	2	2	1	2	1	2
Brain
Lymphocytic perivascular meningitis	0	0	1	1	1–2*	2*	0	0	0	0	3*	2*	0	0	2–3*	2	0	0	0	0	0	0	1	1–2	1–2*	2*
Lymphocytic perivascular encephalitis	0	0	0	0	0	0	0	0	0	0	3*	2*	0	0	0	0	0	0	0	0	0	0	0	0	0	0

^aThe severity (S) and distribution (D) of the histopathological lesions were scored using scales of 0 to 5. For severity, the scores indicate the following: 0, absent; 1, minimal; 2, mild; 3, moderate; 4, marked; 5, severe. For distributions, the numbers indicate the following: 0, absent; 1, focal; 2, multifocal; 3, locally extensive; 4, multifocal and coalescing; 5, diffuse. +, present; −, absent. *, the lesion was not present in all specimens.