Table 3. The degree of cardiac lesions in chickens experimentally infected with Km_5666 and Km_5892.

			Hypertrophied myocardium with atypical nucleusa				Non-suppurative myocarditisb				Fibrosisc		Matrix inclusion bodyd
Inoculated strain	Age (days)	N	−	+	++	+++	−	+	++	+++	−	+	−	+
Km_5666	35	6	5	0	0	1	2	3	0	1	6	0	5	1
	70	3	2	1	0	0	0	1	2	0	3	0	1	2
	140	3	3	0	0	0	0	1	2	0	2	1	1	2
Km_5892	35	4	4	0	0	0	0	2	2	0	3	1	0	4
	70	3	2	0	1	0	0	1	2	0	2	1	0	3

^aThe degree of hypertrophied cardiomyocytes with atypical nuclei was defined as follows: +, individual cells; ++, multiple and/or small clusters; +++, multiple and extensive growth.

^bThe degree of non-suppurative myocarditis was defined as follows: +, focal or multifocal (under 25 µm in diameter); ++, multifocal (from 25 µm to 200 µm); +++, multifocal (over 200 µm).

^cThe degree of fibrosis was defined as follows: +, interstitial; ++, multifocal interstitial (under 400 µm in diameter); +++, multifocal interstitial (over 400 µm in diameter).

^dTotal number in 10 high-power field.