TABLE 1

Virulence of HA point mutants and chimeras in chickensa

VirusNo. of dead chickens/total no. of chickensClinical score
R65-HAR156N3/32.6
R65-HAR156NHA2TG053/32.0
R65-HAR123SHA2TG053/32.1
R65-HAI124THA2TG053/32.1
R65-HAR123I+I124THA2TG053/32.2
  • a Mortality rates and clinical scores were determined after oculonasal infection with 105 PFU of the inoculum virus. Clinical scores were 0 for healthy, 1 for ill, 2 for severely ill, and 3 for dead.