Table 2. Comparison of respiratory droplet transmissibility in sentinel ferrets exposed to HH05 or HH15 influenza virus infection^†.

Virus	Peak virus titre‡ log[pfu/ml]	Day first titre [d post exposure]	Δ first titre cage# [days]
HH05 (pH1N1)	6.9 ± 0.2	7.2 ± 2.1	1.7 ± 1.5
HH15 (pH1N1)	5.5 ± 0.5***	3.3 ± 0.8**	0.7 ± 1.2

^†Cages with sentinel ferrets (n = 6) were placed next to cages with pH1N1-infected ferrets (n = 6; 10⁵p.f.u.; 10 cm distance) for 14 days.

^‡Viral titres were determined in the nasal washes of sentinel animals on days 1–14 p.i. by plaque assay. Sentinel animals were placed pair wise in cages.

^#Delay of first virus titre in nasal wash of second sentinel animal per cage was calculated. Statistical analysis was performed using student’s t-test (two asterisks, p ≤ 0.01; three asterisks, p ≤ 0.001).