vMROGENETICS 
2. Virulence: Commercially available fowlpox vaccines in the U.S are either of 
chick embryo origin and contain live, nonattenuated fowl poxvirus, or are 
attenuated vaccines of cell culture origin (Tripathy, 1991). In a study using a 
TROV AC-based recombinant with the HA gene of a virulent strain of avian 
influenza virus incorporated into the vector’s genome (vFPll), non-vaccinated 
contact control birds were housed with vaccinates, and no evidence of spread 
to non-vaccinated birds was shown. These contact control birds did not 
survive challenge (Appendix F). 
In a study done on swine to observe local reactions after intradermal 
inoculation with four recombinants, including FP-1 and FP-RG (vFP6), 
reactions to both inoculants was very low, even at 10 8 TCED^, with FP-RG 
(vFP6) appearing to be even less reactive than the parental strain FP-1 
(Appendix G). 
When FP-RG (vFP6) was inoculated into chick embryos, there was no effect 
on hatchability or on the health of the hatchlings. One-day-old chickens and 
28 day-old chickens inoculated by the IM route remained completely healthy 
during the 28 day observation period, with no sign of reactivity at the site of 
inoculation. Twenty-eight-day-old birds inoculated via the cutaneous route 
(wing web) showed very mild reaction at the site of inoculation, which cleared 
completely by the end of the observation period (Appendix H). 
3. Immunogenicitv of fowlpox-based vectors: The fowlpox-based vaccine 
against avian influenza (vFPll), when administered to chickens via wing-web 
route, gave complete protection from challenge after a single inoculation 
(Appendix F). Fowlpox-based vaccines administered to chickens against 
Newcastle disease virus gave complete protection from challenge after single 
EM or wing- web inoculations (Appendices I and J). Despite the restriction of 
productive replication in non-avian species, fowlpox-based recombinants are 
capable of expressing extrinsic immunogens and eliciting humoral and cellular 
immune response in mice, rabbits, cats, dogs, cattle and swine (Appendices A, 
B and G). 
4. Environmental distribution: It is anticipated that the TROV AC (FPpp) strain 
of fowlpox virus will have the same range of environmental distribution as the 
currently used commercial vaccine strains. Due to the avian-restricted host- 
range of TROV AC (FPpp), no vertical transmission from avian to mammal or 
mammal to avian is anticipated. 
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