Virus Virus dose, log10 EID50/ferret Day p.i. Virus load (log10 PFU/g) Lung lesions score: individual (average)
Lung Nose
VN/H5N2 LAIV 6.0 3 0 0 0; 1; 0              (0.3)
5 0 0 2; 2; 2              (2.0)
7.0 3 0 0 0; 0; 0                (0)
5 0 0 3; 2; 3              (2.7)
VN/H5N1-RG LAIV 6.0 3 0 0 0; 0; 0                (0)
5 0 0 0; 0; 2              (0.7)
7.0 3 0 0 0; 0; 2              (0.7)
5 0 0 0; 0; 2              (0.7)
t/T/H5N2 LAIV 6.0 3 0 0 2; 0; 0              (0.7)
5 0 0 0; 0; 0                (0)
7.0 3 0 0 0; 2; 2              (1.3)
5 0 0 0; 0; 2              (0.7)
A/turkey/Turkey/1/2005 (H5N1) HPAIV 7.0 3 4.15 4.24 5; 5; 5              (5.0)
5 3.89 4.17 5; 5; 5              (5.0)
A/Vietnam/1194/2004 (H5N1) HPAIV 7.0 3 4.36 4.20 5; 5; 5              (5.0)
5 4.25 3.89 5; 5; 5              (5.0)
A/17/California/2009/38 (H1N1) LAIV 7.0 3 0 0 0; 0; 0                (0)
5 0 0 0; 0; 0                (0)
Placebo (PBS) NO 3 0 0 0; 0; 0                (0)
5 0 0 0; 0; 0                (0)
Virus load was determined in tested samples by plaque titration in MDCK cells. Three animals in each group were tested. Histopathological parameters were scored as: 0 - absent (no visible changes), 1 - minimal, 2 - slight, 3 - moderate, 4 - strong, 5 - severe.
Table 7: Attenuated phenotype of H5-LAIV candidates in experiments on ferrets after intranasal administration.