Live vaccines using either of two avirulent Australian NDV strains selected for their heat stability, V4 or
I-2, have been used with animal feed acting as carriers to combat the specific problems associated
with village chicken rearing in developing countries with variable success. The intention is that this
vaccine could be coated on food easily fed to roaming chickens while being slightly more resistant to
inactivated by high ambient temperatures. Recently, vaccines with both viral strains have been
formulated that produce sufficient HI antibody titres (Olabode et al., 2010) and in some instances
prevent mortality after virulent challenge