Table 3.
Cumulative morbidity and mortality in vaccinated birds challenged by HNLC302 or Md5 strains calculated at 91 days post-challenge (dpc).
| Vaccines * | Strains | Total Numbers | Deaths | Mortality (%) | Diseased Birds # | Morbidity (%) | PI (%) |
|---|---|---|---|---|---|---|---|
| CEF | HN302 | 37 | 24 | 64.86 | 37 | 100.00 | / |
| Md5 | 36 | 29 | 80.56 | 36 | 100.00 | / | |
| HVT | HN302 | 36 | 4 | 11.11 a | 24 | 66.67 a | 33.33 |
| Md5 | 35 | 8 | 22.86 a | 16 | 45.71 a | 54.29 | |
| CVI988 | HN302 | 37 | 12 | 32.43 a | 27 | 72.97 ab | 27.03 b |
| Md5 | 38 | 11 | 28.95 a | 16 | 42.11 ab | 59.89 b |
* Equal volume of mock CEF suspension serves as vaccine negative control. # Surviving birds showing gross tumors inspected at 91 dpc were also calculated as MD cases. a Indicates significant difference between HVT- or CVI988-vaccinated groups and CEF-mock groups challenged by the same virus. b Indicates significant difference between HNLH302 and Md5 viruses in the same vaccination group. “PI” means the protection index. “/” means not applicable.