Table 1.
Specimen collection and IAV-S isolated from different pig production stages and age groups in Vietnam
| IAV-S positive | IAV-S negative | P valuea | Number of IAV-S in each subtype | ||||||
|---|---|---|---|---|---|---|---|---|---|
| number | % | number | % | H1N1 | H1N2 | H3N2 | |||
| Stage | Suckling pig | 0 | 0 | 290 | 4.2 | <0.001 | 0 | 0 | 0 |
| Weanling pig | 107 | 62.2 | 3268 | 47.6 | 19 | 17 | 71 | ||
| Fattening pig | 65 | 37.8 | 2671 | 38.9 | 23 | 32 | 10 | ||
| Finishing pigb | 0 | 0 | 375 | 5.5 | 0 | 0 | 0 | ||
| Sow | 0 | 0 | 240 | 3.5 | 0 | 0 | 0 | ||
| Boar | 0 | 0 | 18 | 0.3 | 0 | 0 | 0 | ||
| Age | 0 to <1 month old | 22 | 12.8 | 467 | 6.8 | <0.001 | 0 | 7 | 15 |
| 1 to <2 months old | 80 | 46.5 | 2593 | 37.8 | 17 | 12 | 51 | ||
| 2 to <3 months old | 46 | 26.7 | 2030 | 29.6 | 14 | 20 | 12 | ||
| 3 to <6 months old | 24 | 14.0 | 1139 | 16.6 | 11 | 10 | 3 | ||
| >6 months old | 0 | 0 | 633 | 9.2 | 0 | 0 | 0 | ||
| Number of viruses isolated | 172 | 42 | 49 | 81 | |||||
aFisher’s exact test
bSamples from finishing pigs were collected at slaughterhouses