Volume 26, Number 2—February 2020
Research Letter
Antigenic Variant of Highly Pathogenic Avian Influenza A(H7N9) Virus, China, 2019
Wenming Jiang, Guangyu Hou, Jinping Li, Cheng Peng, Suchun Wang, Shuo Liu, Qingye Zhuang, Liping Yuan, Xiaohui Yu, Yang Li, Jingjing Wang, and Hualei Liu
Table
Efficacy of H7-Re2 vaccine against highly pathogenic avian influenza A(H7N9) viruses in chickens, China, 2019*
| Vaccine | Challenge virus | Mean HI titer 21 d after vaccination (log2) |
Virus shedding |
Survival rate | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Postchallenge day 3 |
Postchallenge day 5 |
|||||||||
| Challenge virus | H7-Re2 | Trachea | Cloaca | Trachea | Cloaca | |||||
| H7-Re2 |
FQ2 | 3.2 ± 0.6 | 7.7 ± 0.5 | 8/8 (2.6 ± 0.4) | 8/8 (2.4 ± 0.3) | 4/4 (2.3 ± 0.3) | 4/4 (2.5 ± 0.4) | 4/10 | ||
| DL1 |
3.3 ± 0.5 |
7.9 ± 0.4 |
8/8 (2.8 ± 0.3) |
8/8 (2.5 ± 0.3) |
4/4 (2.2 ± 0.4) |
4/4 (2.3 ± 0.3) |
4/10 |
|||
| rFQ2 |
FQ2 | 7.6 ± 0.6 | 7.0 ± 0.5 | 0/10 | 0/10 | 0/10 | 0/10 | 10/10 | ||
| DL1 |
7.3 ± 0.5 |
6.8 ± 0.4 |
0/10 |
0/10 |
0/10 |
0/10 |
10/10 |
|||
| Control | FQ2 | <1 | <1 | 4/4 (4.8 ± 0.5) | 4/4 (4.5 ± 0.4) | NA | NA | 0/10 | ||
| DL1 | <1 | <1 | 4/4 (4.7 ± 0.4) | 4/4 (4.9 ± 0.5) | NA | NA | 0/10 | |||
*HI, hemagglutination inhibition; NA, not applicable because of death of chickens.
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