Table 1.
Influenza viruses isolated from migratory birds in Mai Po Marshes and Poyang Lake, China
| Sampling period* | Bird† | No. of samples | HA subtype and no. of isolates‡ |
|||||
|---|---|---|---|---|---|---|---|---|
| H1 | H3 | H4 | H5 | H6 | H10 | |||
| Nov 2003–Jan 2004 (PL) | Migratory duck (C) | 205 | 3 | 0 | 2 | 0 | 2 | 0 |
| Migratory duck (F) | 587 | 0 | 1 | 2 | 0 | 2 | 2 | |
| Migratory goose (F) | 250 | 0 | 0 | 0 | 0 | 0 | 0 | |
| Oct 2003–Mar 2004 (MP) | Migratory duck (F) | 6,005 | 0 | 0 | 5 | 2 | 2 | 5 |
| Oct 2004–Mar 2005 (PL) | Migratory duck (C) | 4,316 | 2 | 2 | 3 | 6 | 2 | 1 |
| Total | 13,115 | 5 | 3 | 12 | 8 | 8 | 8 | |
C, cloacal; F, fecal; MP, Mai Po Marshes; PL, Poyang Lake.
*Earlier sampling at Poyang Lake, December 2002 to February 2003 (153 tracheal swabs, 419 fecal swabs from migratory ducks; 602 fecal swabs from migratory geese; 578 fecal swabs from swans) yielded no influenza viruses.
†Migratory ducks included falcated teal (Anas falcata), mallard ducks (Anas platyrhynchos), and spot-billed ducks (Anas poecilorhyncha). Subtypes were identified by using World Health Organization reference anti-sera and H5 anti-sera available in our laboratory and were confirmed by PCR and sequencing reactions.
‡An additional 30 isolates from migratory ducks could not be identified with the reference anti-sera.