Table 1.

Overview of the experimental transmission studies

				Number of contact birdsb
Experiment	Vaccine	Virus	HI titrea (log2)	Infected	Dead
1	La Sota	NL93	0 to 2	9, 10	0, 1
2	La Sota	Herts33/56	0 to 2	5	0
3	La Sota	California71	0 to 2	10	1
4	Ulster	NL93	0 to 2	10, 10	4, 4
5	La Sota	NL93	≥3	0, 4, 10	0, 0, 0
6	La Sota	Herts33/56	≥3	0, 2	0, 0
7	La Sota	California71	≥3	1, 3	0, 1
8	Ulster	NL93	≥3	7	0

Experiments 2, 3, and 8 consist of one trial, Experiments 1, 4, 6, and 7 contain two trials, and Experiment 5 contains three trials. Each trial initially contained 10 infected birds and 10 uninfected contact birds. The vaccines are based on the La Sota (Nobilis Clone30) and Ulster (NDW Poulvac) viruses. The challenge viruses are NL93 (APMV-1/chicken/Netherlands/152608/93), Herts33/56, and California71.

^aRange of HI titres of the birds just before the start of the experiment.

^bNumber of contact birds that were infected or died per trial.