Table 1.

Pathogenicity of GP-expressing recombinant viruses in embryonated eggs and 1-day-old chicks.

Virus	MDTa (h)
rNDV-3FH WT	>114
rAPMV-3 N/P-GP	>168
rNDV-3FH N/P-GP	>168
Virus	ICPI b
rNDV-3FH WT	0.08
rAPMV-3 N/P-GP	0.63
rNDV-3FH N/P-GP	0.51

^aMean embryo death time (MDT): the mean time (h) for the minimum lethal dose of virus to kill all of the inoculated embryos⁴². Pathotype definition: virulent strains, <60 h; intermediate virulent strains, 60 to 90 h; avirulent strains, >90 h.

^bIntracerebral pathogenicity index (ICPI): evaluation of disease and death following intracerebral inoculation in 1-day-old SPF chicks⁴². Pathotype definition: virulent strains, 1.5–2.0; intermediate virulent strains, 0.7–1.5; and avirulent strains, 0.0–0.7.