Table 1. Mortality rates and MDTs of chickens with the A/duck/Korea/Es2/2016 virus via intranasal inoculation by titers.
| Breed | Dose (EID50/0.1 mL) | Mortality (%) | MDT | Antibody detection | cLD50 (EID50/0.1 mL) |
|---|---|---|---|---|---|
| SPF chicken | 106.0 | 8/8 (100) | 2.6 | - | 103.7 |
| 105.0 | 4/4 (100) | 6.3 | - | ||
| 104.0 | 3/4 (75) | 7.9 | 0/1 | ||
| 103.0 | 0/4 (0) | 0/4 | |||
| Contact | 3/3 (100) | 3.2 | - | ||
| Broiler chicken | 106.0 | 8/8 (100) | 2.1 | - | 103.8 |
| 105.0 | 5/5 (100) | 2.8 | - | ||
| 104.0 | 3/5 (60) | 4.9 | 0/2 | ||
| 103.0 | 0/5 (0) | 0/5 | |||
| Contact | 3/3 (100) | 3.9 | - | ||
| KNC | 107.0 | 5/5 (100) | 3.1 | - | 104.3 |
| 106.0 | 8/8 (100) | 3.1 | - | ||
| 105.0 | 4/5 (80) | 6.3 | 0/1 | ||
| 104.0 | 2/5 (40) | 6.0 | 0/3 | ||
| Contact | 3/3 (100) | 6.7 | - |
To investigate pathogenicity in chicken breed by titers, each breed of chicken was intranasally inoculated serial 10-fold dilutions, ranging from 102.6 to 106.6 EID50 titers of ES2 virus. To study pathogenicity and transmissibility in 3 kinds of chicken breeds, SPF chicken, broiler chicken, and KNCs were intranasally inoculated with 105.6 EID50 of ES2 virus. Ten hours later, uninfected chickens were co-housed with the each infected chicken breed. These co-housed uninfected chickens were called contact group.
KNC, Korean native chicken; MDT, mean death time; cLD50, the chicken median lethal dose; EID50, 50% egg infective doses; SPF, specific pathogen-free.