TABLE 1.
Susceptibility of avian influenza A viruses of the N6 NA subtype to the NAI oseltamivir.
| N6 NA influenza viruses | Subtype | Year of isolation | Origin | Mean IC50 ± SD (nM) b |
|---|---|---|---|---|
| Isolated from ducks a | ||||
| A/Canvasback Duck/Alberta/102/1976 | H3N6 | 1976 | Canada | 0.35±0.08 |
| A/Mallard Duck/Alberta/100/1976 | H3N6 | 1976 | Canada | 0.04±0.09 |
| A/Mallard Duck/Alberta/22/1976 | H3N6 | 1976 | Canada | 0.06±0.12 |
| A/Mallard Duck/Alberta/44/1976 | H3N6 | 1976 | Canada | 1.26±0.83 |
| A/Mallard Duck/Alberta/97/1976 | H3N6 | 1976 | Canada | <0.01c |
| A/Mallard Duck/Alberta/20/1976 | H4N6 | 1976 | Canada | 0.11±0.08 |
| A/Mallard Duck/Alberta/37/1976 | H4N6 | 1976 | Canada | 0.11±0.22 |
| A/Pintail Duck/ Alberta/1/1976 | H4N6 | 1976 | Canada | 0.05±0.13 |
| A/Pintail Duck/Alberta/53/1976 | H4N6 | 1976 | Canada | 7.4±0.42 |
| A/Pintail Duck/Alberta/211/1979 | H4N6 | 1979 | Canada | 0.09±0.22 |
| A/Pintail Duck/Alberta/358/1979 | H3N6 | 1979 | Canada | <0.01 |
| A/Mallard Duck/Minnesota/1041/1980 | H6N6 | 1980 | USA | 1.28±0.05 |
| A/Mallard Duck/Alberta/145/1981 | H4N6 | 1981 | Canada | 0.68±0.71 |
| A/Mallard Duck/Alberta/635/1985 | H6N6 | 1985 | Canada | 0.2±0.28 |
| A/Blue-wing Teal Duck/Alberta/888/1985 | H4N6 | 1985 | Canada | 0.7±0.1 |
| A/Mallard Duck/Alberta/697/1985 | H4N6 | 1985 | Canada | 5.33±0.99 |
| A/Pintail Duck/Alberta/623/1985 | H4N6 | 1985 | Canada | 0.05±0.07 |
| A/Mallard Duck/Alberta/17/1989 | H4N6 | 1989 | Canada | 0.28±0.04 |
| A/Mallard Duck/Alberta/131/1991 | H2N6 | 1991 | Canada | 0.13±0.01 |
| A/Mallard Duck/Alberta/132/1991 | H2N6 | 1991 | Canada | <0.01 |
| A/Mallard Duck/Alberta/135/1991 | H2N6 | 1991 | Canada | 0.25±0 |
| A/Mallard Duck/Alberta/25/1992 | H3N6 | 1992 | Canada | 0.14±0.01 |
| A/Mallard Duck/Alberta/35/1992 | H3N6 | 1992 | Canada | 5.32±0.2 |
| A/Mallard Duck/Alberta/183/1992 | H4N6 | 1992 | Canada | 0.12±0.01 |
| A/Mallard Duck/Alberta/119/2000 | H4N6 | 2000 | Canada | 0.06±0.08 |
| A/Mallard Duck/Alberta/35/2001 | H4N6 | 2001 | Canada | 1.28±0.08 |
| A/Pintail Duck/Alberta/269/2001 | H4N6 | 2001 | Canada | 4.35±0.21 |
| A/Mallard Duck/Alberta/76/2002 | H3N6 | 2002 | Canada | 3.90±0.16 |
| A/Pintail Duck/Alberta/166/2003 | H3N6 | 2003 | Canada | 7.52±0.37 |
| A/Mallard Duck/Alberta/237/2003 | H4N6 | 2003 | Canada | 0.10±0.13 |
| A/Mallard/Alberta/33/2004 | H4N6 | 2004 | Canada | 0.35±0.08 |
| A/Mallard Duck/Alberta/201/2005 | H4N6 | 2005 | Canada | 0.41±0.12 |
| A/Mallard Duck/Alberta/205/2005 | H4N6 | 2005 | Canada | 0.27±0.15 |
| A/Pintail Duck/Alberta/66/2005 d | H4N6 | 2005 | Canada | 2.10±0.01 |
| A/Blue-wing Teal Duck/Alberta/376/2007 | H3N6 | 2007 | Canada | 0.04±0.09 |
| A/Mallard Duck/Minnesota/Sg-000185/2007 | H3N6 | 2007 | USA | 1.18±0.01 |
| A/Bufflehead Duck/Alberta/418/2007 | H4N6 | 2007 | Canada | 0.47±0.08 |
| A/Northern Pintail Duck/Alberta/335/2007 | H4N6 | 2007 | Canada | 2.37±0.1 |
| A/Blue-wing Teal Duck/Minnesota/Sg-00899/2008 | H4N6 | 2008 | USA | 0.13±0.02 |
| A/Mallard Duck/Alberta/121/2008 | H4N6 | 2008 | Canada | 0.03±0.07 |
| A/Mallard Duck/Alberta/572/2008 | H4N6 | 2008 | Canada | 0.11±0 |
| A/Mallard Duck/Minnesota/Sg-00569/2008 | H4N6 | 2008 | USA | 0.12±0.01 |
| A/Mallard Duck/Minnesota/Sg-00971/2008 | H4N6 | 2008 | USA | 0.42±0.04 |
| A/Mallard Duck/Minnesota/Sg-01051/2008 | H4N6 | 2008 | USA | 0.12±0.01 |
| A/Northern Pintail Duck/Minnesota/Sg-00898/2008 | H4N6 | 2008 | USA | 0.15±0.01 |
| A/Mallard Duck/Minnesota/AI10-1708/2010 | H13N6 | 2010 | USA | <0.01 |
| Overall duck isolates | 1.07±1.93 | |||
|
| ||||
| Isolated from shorebirds/gulls a | ||||
| A/Gull/Maryland/684/1977 | H3N6 | 1977 | USA | <0.01 |
| A/Gull/MA/18/1980 | H13N6 | 1980 | USA | <0.01 |
| A/Gull/MA/50/1980 | H13N6 | 1980 | USA | 0.28±0.05 |
| A/Gull/Minnesota/ 945/1980 | H13N6 | 1980 | USA | 0.83±0.04 |
| A/Herring Gull/Delaware/660/1988 | H13N6 | 1988 | USA | 30.00±0.01 |
| A/Herring Gull/Delaware/665/1988 | H4N6 | 1988 | USA | 40.00±0.01 |
| A/Herring Gull/New Jersey/136/1990 | H3N6 | 1990 | USA | 1.28±0.27 |
| A/Herring Gull/New Jersey/144/1990 | H3N6 | 1990 | USA | 0.16±0.04 |
| A/Gull/New Jersey/34/1992 | H13N6 | 1992 | USA | 0.14±0.05 |
| A/Gull/New Jersey/48/1992 | H13N6 | 1993 | USA | 0.22±0.11 |
| A/Ruddy Turnstone/New Jersey/AI01-1407/2001 | H13N6 | 2001 | USA | <0.01 |
| A/Shorebird/Delaware/231/2001 | H13N6 | 2001 | USA | <0.01 |
| A/Ruddy Turnstone/New Jersey/1321394/2005 | H3N6 | 2005 | USA | 0.12±0 |
| A/Shorebird/Delaware/518/2005 | H3N6 | 2005 | USA | 0.30±0.39 |
| A/Ruddy Turnstone/New Jersey/1321394/2005 | H3N6 | 2005 | USA | 1.48±0.01 |
| A/Ruddy Turnstone/New Jersey/Sg-00502/2008 | H4N6 | 2008 | USA | 6.70±0.01 |
| A/Shorebird/Delaware/606/2008 | H4N6 | 2008 | USA | 0.23±0.27 |
| A/Shorebird/Delaware/309/2008 | H4N6 | 2008 | USA | 0.13±0.01 |
| A/Ruddy Turnstone/New Jersey/Sg-00551/2008 | H6N6 | 2008 | USA | 0.1±0.1 |
| A/Ring-billed Gull/Minnesota/AI0-1784/2010 | H13N6 | 2010 | USA | <0.01 |
| A/Ring-billed Gull/Minnesota/AI0-1791/2010 | H13N6 | 2010 | USA | 1.13±0.13 |
| A/Ring-billed Gull/Minnesota/AI0-1820/2010 | H13N6 | 2010 | USA | 1.29±0.08 |
| A/Ring-billed Gull/Minnesota/AI0-1829/2010 | H13N6 | 2010 | USA | 0.49±0.34 |
| A/Ring-billed Gull/Minnesota/AI10-1725/2010 | H13N6 | 2010 | USA | 0.86±0.71 |
| A/Ring-billed Gull/Minnesota/AI10-1738/2010 | H13N6 | 2010 | USA | 1.01±0.96 |
| A/Ring-billed Gull/Minnesota/AI10-1778/2010 | H13N6 | 2010 | USA | 0.19±0.01 |
| A/Ring-billed Gull/Minnesota/AI10-1765/2010 | H13N6 | 2010 | USA | 0.06±0.08 |
| Overall shorebird/gull isolates | 3.22±10.30 | |||
a
Avian influenza viruses were all from apparently healthy wild birds and were isolated from fecal samples or from tracheal/oropharyngeal or cloacal swabs.
b
NA inhibition assay used MUNANA as substrate at a final concentration of 100 μM. Values are the mean of two or three independent determinations.
c
Values from 0.005 to 0.01 were included in calculating the IC50 values.
d
A/Pintail Duck /Alberta/66/2005 (H4N6) influenza virus that was sensitive to oseltamivir was counted in the total number of pintail isolates after it was purified out.