Volume 17, Number 6—June 2011
Dispatch
Novel Reassortant Highly Pathogenic Avian Influenza (H5N5) Viruses in Domestic Ducks, China
Table 1
Characteristics of 2 novel avian influenza (H5N5) viruses isolated from domestic ducks, China, December 2008–January 2009*
| Virus | Characteristics |
Virus replication in experimentally infected mice,
no. virus-positive mice/no. tested mice (mean titer + SD)† |
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| IVPI | EID50 | TCID50 | MLD50‡ | Tissue | dpi 2 | dpi 4 | dpi 6 | dpi 8 | dpi 10 | ||
| 008 |
2.6 |
108.5 |
108.6 |
104.0 |
Lung | 1/2 (3.2 ± 0) | 2/2 (3.8 ± 0.4) | 2/2 (4.7 ± 0.4) | 2/2 (4.4 ± 0.5) | 0/2 | |
| Brain | 0/2 | 0/2 | 0/2 | 2/2 (3.8 ± 1.2) | 1/2 (3.4 ± 0) | ||||||
| Heart | 1/2 (2.0 ± 0) | 2/2 (2.6 ± 0.5) | 2/2 (3.1 ± 0.1) | 0/2 | 0/2 | ||||||
| Spleen | 0/2 | 0/2 | 0/2 | 0/2 | 1/2 (2.3 ± 0) | ||||||
| Liver | 0/2 | 0/2 | 1/2 (2.2 ± 0) | 0/2 | 0/2 | ||||||
| Kidney |
0/2 |
0/2 |
0/2 |
0/2 |
0/2 |
||||||
| 031 | 2.5 | 108.3 | 108.5 | 105.4 | Lung | 1/2 (3.0 ± 0) | 1/2 (3.3 ± 0) | 2/2 (4.1 ± 0.2) | 2/2 (4.5 ± 0.3) | 1/2 (2.6 ± 0) | |
| Brain | 0/2 | 0/2 | 0/2 | 1/2 (3.4 ± 0) | 0/2 | ||||||
| Heart | 0/2 | 1/2 (2.5 ± 0) | 1/2 (3.0 ± 0) | 0/2 | 0/2 | ||||||
| Spleen | 0/2 | 0/2 | 0/2 | 0/2 | 0/2 | ||||||
| Liver | 0/2 | 0/2 | 0/2 | 0/2 | 0/2 | ||||||
| Kidney | 0/2 | 0/2 | 1/2 (2.1 ± 0) | 0/2 | 0/2 | ||||||
*EID50, 50% egg infectious dose; IVPI, intravenous pathogenicity index (determined in chickens); TCID50, 50% tissue culture infectious dose (determined in MDCK cells); MLD50, 50% lethal dose in mice (expressed as the EID50 value corresponding to 1 LD50); dpi, day postinoculation; 008, A/duck/eastern China/008/2008; 031, A/duck/eastern China/031/2009.
†Mice were inoculated with 103.5 EID50; 2 infected mice were euthanized every other day for virus detection. Virus titers were expressed as log10 EID50/g.
‡Influenza A viruses with MLD50 <103.0 EID50 were considered of high pathogenicity, MLD50 >106.5 EID50 were considered of low pathogenicity (4).
