Volume 21, Number 2—February 2015
Research
Novel Reassortant Influenza A(H5N8) Viruses among Inoculated Domestic and Wild Ducks, South Korea, 2014
Table 4
Virus isolation from swab samples obtained from mallard ducks inoculated with H5N8 and H5N1 influenza viruses*
| Virus | Group | No. dead/no inoculated | Clinical signs | Virus titer, log10TCID50/0.1 mL, mean±SD (no. positive/no. ducks)† |
HI titer |
||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Oropharyngeal swab sample results, (days post-inoculation) |
Cloacal swab sample results (days post-inoculation) |
||||||||||||||||||
| 1 | 3 | 5 | 7 | 10 | 14 | 1 | 3 | 5 | 7 | 10 | 14 | ||||||||
| A/broiler duck/Kr/Buan2/2014 (H5N8) |
Inoculated | 0/5 | None | 1.0 ± 0.5 (4/7) | 3.4 ± 0.6 (6/7) | 1.5 (1/5) | 0 (0/5) | 0 (0/5) | 0 (0/5) | 0 (0/7) | 2.7 ± 1.2 (2/7) | 0 (0/5) | 0 (0/5) | 0 (0/5) | 0 (0/5) | 4/5 | |||
| Contact‡ |
0/2 |
None |
0 (0/2) |
2.2 ± 0.9 (2/2) |
2.5 (1/2) |
0 (0/2) |
0 (0/2) |
0 (0/2) |
0 (0/2) |
0.6 (1/2) |
0 (0/2) |
0 (0/2) |
0 (0/2) |
0 (0/2) |
2/2 |
||||
| A/chicken/Kr/IS/2006 (H5N1) |
Inoculated | 0/2 | Mild§ | 1.8 (1/4) | 2.0 ± 0.2¶ (4/4) | 0 (0/2) | 0 (0/2) | 0 (0/2) | 0 (0/2) | 0 (0/4) | 0 (0/4) | 0 (0/2) | 0 (0/2) | 0 (0/2) | 0 (0/2) | 2/2 | |||
| Contact |
0/2 |
None |
0 (0/2) |
1.8 (1/2) |
0 (0/2) |
0 (0/2) |
0 (0/2) |
0 (0/2) |
0 (0/2) |
0 (0/2) |
0 (0/2) |
0 (0/2) |
0 (0/2) |
0 (0/2) |
1/2 |
||||
| A/mandarin duck/Kr/PSC24–24/2010 (H5N1) |
Inoculated | 0/2 | Mild | 0 (0/4) | 2.0 ± 1.2 (4/4) | 0 (0/2) | 0 (0/2) | 0 (0/2) | 0 (0/2) | 0 (0/4) | 0 (0/4) | 0 (0/2) | 0 (0/2) | 0 (0/2) | 0 (0/2) | 1/2 | |||
| Contact |
0/2 |
Mild |
0 (0/2) |
2.0 ± 0.8 (2/2) |
0 (0/2) |
0 (0/2) |
0 (0/2) |
0 (0/2) |
0 (0/2) |
0 (0/2) |
0 (0/2) |
0 (0/2) |
0 (0/2) |
0 (0/2) |
0/2 |
||||
| Control | NA | 0/2 | None | 0 (0/2) | 0 (0/2) | 0 (0/2) | 0 (0/2) | 0 (0/2) | 0 (0/2) | 0 (0/2) | 0 (0/2) | 0 (0/2) | 0 (0/2) | 0 (0/2) | 0 (0/2) | 0/2 | |||
*Birds were inoculated intranasally with 106.5 egg-infective dose/0.1 mL of virus; oropharyngeal and cloacal swab samples were taken on the indicated day; HI, hemagglutination inhibition titer. HI titer was assayed in serum taken at 14 days post-inoculation. Data show the ratio of the number of antibody-positive animals to the number of virus-inoculated animals.
†Virus titer is an average of the virus titers of positive samples.
‡A pair of control birds were co-housed with the infected birds as a contact group at 8 h after inoculation.
§Mild clinical signs, diarrhea or cloudy eye.
¶Significant differences in oropharyngeal shedding between Buan2 and IS06 on day 3 post-inoculation (p<0.01) as estimated by the Student t-test.