TABLE 5.
Pathogenicity and transmissibility of A(H9N2) viruses in ferrets
| Experimental group | Wt lossa | Tempb | Nas disc | Peak NWd | Transe | Serof |
|---|---|---|---|---|---|---|
| HK/1073 | ||||||
| Inoculated | 6.2 (2/6) | 1.7 (6/6) | 3/6 | 6.8 (6/6) | NA | 320–640 (3/3) |
| DC contact | 5.0 (1/3) | 1.5 (3/3) | 0/3 | 6.5 (3/3) | 2/3 | 320 (2/3) |
| RD contact | None (0/3) | 1.3 (2/3) | 0/3 | <1.5 (0/3) | 0/3 | <10 (0/3) |
| HK/308 | ||||||
| Inoculated | 8.4 (4/6) | 1.4 (6/6) | 1/6 | 7.8 (6/6) | NA | 640–2,560 (6/6) |
| DC contact | None (0/3) | 1.0 (1/3) | 0/3 | 7.8 (3/3) | 3/3 | 640–2,560 (3/3) |
| RD contact | 16.8 (1/3) | None (0/3) | 0/3 | 3.0 (3/3) | 2/3 | 20–40 (2/3) |
| A-L/39 | ||||||
| Inoculated | 11.2 (9/9) | 1.6 (9/9) | 7/9 | 8.2 (9/9) | NA | 2,560–10,240 (9/9) |
| DC contact | 10.9 (3/3) | 2.3 (3/3) | 3/3 | 8.8 (3/3) | 3/3 | 5,120 (3/3) |
| RD contact | 7.8 (3/6) | 1.6 (5/6) | 0/6 | 8.0 (5/6) | 5/6 | 2,560–10,240 (5/6) |
Percentage mean maximum weight loss during days 1 to 14 p.i./p.c. following inoculation with 106 EID50/ml of virus. No. of ferrets with weight loss ≥5%/total no. of ferrets is in parentheses.
Mean maximum rise in degrees Celsius above baseline temperature (37.8 to 39.1°C) during days 1 to 14 p.i./p.c. No. of ferrets with temperature rise >1°C/total no. of ferrets in parentheses.
No. of ferrets with detected nasal discharge or sneezing during days 1 to 14 p.i./p.c./total no. of ferrets.
Mean maximum viral titer in ferret nasal wash (NW) specimens expressed as log10 EID50/ml. No. of ferrets with detectable virus/total no. of ferrets is in parentheses; limit of detection is 101.5 EID50/ml.
Transmission (Trans) is shown as the number of contact ferrets with viral titers in NW and seroconversion to homologous virus/total no. of ferrets. NA, not applicable. DC, direct contact; RD, respiratory droplets.
Seroconversion range to homologous virus as determined by HI assay. Titers represent the reciprocal of the dilution that inhibited hemagglutination. No. of ferrets with seroconversion/total no. of ferrets in parentheses. Serum was collected days 17–21 p.i./p.c.