Deletions of neuraminidase and resistance to oseltamivir may be a consequence of restricted receptor specificity in recent H3N2 influenza viruses

Table 1 Single internal deletions in the NA genes of H3N2 viruses isolated from 2003 to 2008.

Virus	Passage No.¹	First block 1 to ...	Second block ... to 1467	Length of fragment
Fujian-like virus
OK/323/03	P7Ld1	181	1194	454
	P10H+1Ld1	82	1209
	P10H+2Ld1	82	1209	341
	P13Ld1	261	1181	547
	P14Hd1	73	1207	333
California-like virus
OK/1992/05	P2Hd1	51	1148	370
	P2Ld1	145	1244	368
	P3Ld1	145	1244	368
	P3Hd1	125²	1301	320
Wisconsin-like viruses
OK/1472/06	P1d2	221	1166	522
OK/51/06	P1d1	40	1244	263
Brisbane-like viruses
OK/5545/07	P1d1	231	1308	390
OK/1806/08	P1d1	145	1210	402
OK/483/08	P1d1	145	1261	351

¹PCR products are numbered from larger to smaller. P2Hd1 is the larger deleted product seen at passage 2 (P2) under higher (H) moi. P7Ld1 was from the 7^th passage under limiting dilution (L).
² 29 nucleotides in between are unidentified

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