Comparative analysis of apoptotic changes in peripheral immune organs and lungs following experimental infection of piglets with highly pathogenic and classical porcine reproductive and respiratory syndrome virus

Table 1 Histopathological changes of immune organs and lungs at different days post-inoculation (DPI)

Group	DPI^*	Histological lesion score^#(No. of piglets with lesions/no. of piglets examined)
		Tonsil		ILN		Spleen		Lung
		a	b	a	b	a	b	c
1	0	0	0	0	0	0	0	0
	3	1 (1/3)	0	1 (2/3)	1 (1/3)	1 (2/3)	0	1 (1/3)
	7	2 (3/3)	1 (1/3)	1.5 (2/3)	1 (2/3)	1 (2/3)	1.5 (2/3)	1 (2/3)
	10	3 (3/3)	2.7 (3/3)	1.7 (3/3)	1.7 (3/3)	2 (3/3)	2 (2/3)	3 (3/3)
	14	3 (3/3)	3 (3/3)	3 (3/3)	2 (3/3)	3 (3/3)	2 (3/3)	4 (3/3)
2	0	0	0	0	0	0	0	0
	3	0	0	0	0	0	0	0
	7	2 (1/3)	0	1 (2/3)	0	0	1 (1/3)	1 (1/3)
	10	2 (2/3)	1.3 (3/3)	1 (2/3)	0	1 (2/3)	0	1.3 (3/3)
	14	1 (1/3)	1 (2/3)	1 (2/3)	1 (2/3)	1 (2/3)	1.5 (2/3)	1.3 (2/3)

^* Days post-inoculation when pigs were necropsied.
^# Mean histological lesion score of piglets with lesions.
a Histological lymphoid depletion score: 0, normal; 1, mild; 2, moderate; 3, severe.
b Inflammation and replacement of follicles score: 0, normal; 1, mild; 2, moderate; 3, severe.
c Interstitial pneumonia score: 0, no microscopic lesions; 1, mild interstitial pneumonia; 2, moderate multifocal interstitial pneumonia; 3, moderate diffuse interstitial pneumonia; 4, severe interstitial pneumonia.

ISSN: 1743-422X