Figure 5.

Protective efficacy of CHv-ΔgC/gE against lethal CHv challenge in ducklings. (A) Rectal temperatures and body weight changes of ducklings challenged after immunization. (B) Clinical symptoms of immunized ducklings after challenge with 100 LD₅₀ CHv. (C) Survival curves of ducklings after challenge with 100 LD₅₀ CHv. (D) Rectal viral excretion by ducklings after challenge with 100 LD₅₀ CHv. (E) Quantification of viral DNA loads in heart, liver,spleen, duodenum, rectum and thymus tissues of the vaccinated duckings after challenge. (F) Postmortem examination of ducklings in each group at 6 dpi. There are obvious bleeding, congestion, ulcers and other lesions at the arrow. (G) Histological analysis of heart, liver,spleen, duodenum, rectum and thymus from the indicated groups after challenge with CHv-ΔgC/gE, Vaccine or MEM (control) (hematoxylin and eosin staining, 100× magnification). *p<0.05; **p<0.01; ***p<0.001; ****p<0.0001; and ns, not significant.