TABLE 3.
Seroprevalencea to influenza A subtype H3N2 and H9N2 viruses in pigs
| Viral antigen | Serological testb | No. of sera (%) reactive in yrc
|
||
|---|---|---|---|---|
| 1998 (n = 117) | 1999 (n = 46) | 2000d(n = 294) | ||
| Dk/HK/Y280/97 (H9N2) | NT | 0 (0) | 0 (0) | 2 (0.7) [20–40] |
| Sw/HK/9/98 (H9N2) | NT | 0 (0) | 0 (0) | 2 (0.7) [20] |
| Qa/HK/G1/97 (H9N2) | NT | 0 (0) | 0 (0) | NDe |
| Dk/HK/Y280/98 (H9N2) | HAI | 2 (2) [80] | 2 (4) [160] | 16 (5) [80–640] |
| Sw/HK/9/98 (H9N2) | HAI | 1 (1) [80] | 1 (2) [80] | 8 (3) [80–320] |
| Ck/HK/G9/97 (H9N2) | HAI | 1 (1) [160] | 5 (11) [80–320] | 8 (3) [80–160] |
| Qa/HK/G1/97 (H9N2) | HAI | 0 (0) | 0 (0) | 0 (0) |
| Dk/HK/Y439/97 (H9N2) | HAI | 0 (0) | 0 (0) | 0 (0) |
| Sw/HK/2422/98 (H3N2) | NT | 34 (29) [20–>320] | 2 (4) [160, 320] | 43 (15) [20–>320] |
| Sw/HK/2422/98 (H3N2) | HAI | 18 (15) [80–1,280] | 2 (4) [320–2,560] | 57 (19) [80–1,280] |
a
HAI positives were taken as titers of 1/80 or more. Neutralization positives were taken as titers of 1/20 or more.
b
NT, neutralization test.
c
Values in brackets show the range of the antibody titers.
d
January to June.
e
ND, not determined..