TABLE 4.
Counts of all high-identity segment matches at a 1% cutoff for avian-origin AIV isolates from the Mississippi Migratory Flyway compared to all available AIV isolates in the Influenza Research Database/GenBank from June 2008 to March 2011
| Factor | No. of high-identity matches |
||
|---|---|---|---|
| Within season | Across two seasonsc | Across three seasons | |
| Distance (km)a | |||
| 0–500 | 1,319 | 417 | 26 |
| 500–1,000 | 467 | 305 | 63 |
| 1,000–1,500 | 317 | 176 | 50 |
| 1,500–2,000 | 103 | 113 | 15 |
| 2,000–2,500 | 154 | 49 | 2 |
| 2,500–3,000 | 123 | 79 | 49 |
| 3,000–3,500 | 3 | 9 | 2 |
| 3,500–4,000 | 0 | 0 | 0 |
| 4,000–4,500 | 8 | 0 | 22 |
| 4,500–5,000 | 52 | 2 | 0 |
| 5,000–5,500 | 10 | 8 | 0 |
| 5,500–6,000 | 0 | 0 | 0 |
| Gene segmentb | |||
| PB2 | 272 | 64 | 0 |
| PB1 | 244 | 77 | 4 |
| PA | 153 | 23 | 0 |
| HA | 189 | 48 | 0 |
| NP | 228 | 67 | 4 |
| NA | 340 | 252 | 84 |
| MP | 347 | 160 | 37 |
| NS | 783 | 466 | 100 |
a
χ2 = 587.66; df = 18; P < 0.01.
b
χ2 = 271.27; df = 14; P < 0.01.
c
Time classes were defined by the number of days between isolations of the two isolate segments included in each pairwise high-identity match (i.e., across two seasons represents a difference of 200 to 400 days between isolation).