Table 2.

Prevalence of NS1 truncation in the C-terminal end in 9 neuraminidase subtypes of avian influenza viruses from 1902 to 2015.

Subtype	202	207	212	214	216	217	219	220	224	225	227	228	229	230	237	238	Total ΔNS1 CTE***,**	Total NS1 sequences	%
N1	2		3			89	12	45	84		1	76	1	2990	18	1	313	3322	9.4
N2			1			1252	24	6		6		4		2070	27		1293	3390	38.1
N3				1	2	39								903	1		41	945	4.3
N4														256			0	256	0
N5						5								314			5	319	1.6
N6	3					189	6							1353	4		198	1555	12.7
N7						36								714			36	750	4.8
N8		1				33		1						1373	62		35	1470	2.4
N9	1			1		408								609			410	1019	40.2
Total ΔNS1 CTE	6	1	4	1	2	2051	42	52	84	6	1	80	1	10582	112	1	2331	13026	17.9
%*	0.3	0.01	0.2	0.01	0.1	88.0	1.8	2.2	3.6	0.3	0.01	3.4	0.01	81.2	0.9	0.01

^*percentage of truncated NS1 CTE sequences/total positive (2331 sequences)

^**sum of truncated forms only (202–229)