Table 1.

Sequential information and pathogenicity of two viruses in this study

Isolate name	Host	Separatum	Isolate year	EID 50/0.2 ml	ICPI a	MDT(h) b	Fusion protein cleavage site c
SS-10	Duck	Sanshui	2010	10 -9.83	1.89	51.6	112RRQKRF117
NH-10	Duck	Nanhai	2010	10-9.62	1.7	58.8	112RRQRRF117

^aA strain with an ICPI below 0.7 was considered to be lentogenic, while those with an ICPI equal to or greater than 1.60 were considered to be velogenic, and those with ICPI values between 0.7 and 1.60 were considered to be mesogenic. The ICPI of avirulent viruses were near 0.00 [2].

^bFor 9-day-old embryonated chicken eggs, the mean death time (MDT) value (h) of more than 90 was defined as lentogenic; 60–90 as mesogenic, and under 60 as velogenic.

^cCleavage site sequences (residues 112 to 117) of the F protein.