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Inc). Other commercial vaccines preparations include FAdV-11 demonstrates the practicality and applicability of fowl adeno-
(e.g. Farvet). viruses as vectors for the production of poultry vaccines and as
The use of recombinant DNA technology has allowed the vehicles for gene delivery.
development of new candidate vaccines during the last 10 years.
The penton base subunit vaccine (Shah et al., 2012) and fibre-2
protein of FAdV-4 (patent publication US 20160193323 A1) Perspectives
have been developed to control HPS. Other candidate vaccines The taxonomy of adenoviruses is constantly changing and thus
for HPS/IBH or GE include fibre-2 protein of FAdV-A, fibre the assignation of new species groups and inclusion of some yet-
protein of FAdV-B, FAdV-D and FAdV-E (patent publication WO to-be-classified viruses in any of the genera are to be expected.
2015024929 A3). A live-attenuated vaccine has been developed The growing number of epizootiological studies and reports of
by propagation of chicken embryo-adapted FAdV-4 (Mansoor et novel molecular methods for diagnosis have provided further
al., 2011). insights into virus-induced pathogenesis, virulence factors and
prevalence. These studies will continue and be fundamental for
the identification of potential virulence factors and development
Aviadenovirus as vaccine and gene delivery of effective vaccines for disease control. Further advances in
vector molecular cloning will allow the rapid and efficient generation of
Mammalian adenoviruses are best characterized and used as new virus-based vectors for applications in gene delivery and vac-
vectors for various purposes such as gene delivery, vaccina- cine development. Due to their large genome with dispensable
tion, and oncolytic therapeutics (Wold and Toth, 2013). Fowl regions for in vitro replication, aviadenoviruses are expected to be
adenoviruses are less characterized, though their potential as the most used platforms for the development of monovalent and
vaccine vectors have been demonstrated. Owing to the larger multivalent vaccines for poultry. Lastly, further studies on viral
size and gene arrangements of their genomes, the FAdVs have gene function will reveal novel mechanisms by which the virus
considerable capacity for foreign gene insertion. Recombinant modulates the host cell to favour its own replication and provide
viruses were generated using various insertion sites by replacing further understanding on the molecular basis of virus-induced
non-essential regions at the right ends of the genomes of FAdV-1, pathogenesis.
FAdV-8, FAdV-9, and FAdV-10 (Sheppard et al., 1998b; Michou
et al., 1999; François et al., 2001; Ojkic and Nagy, 2001; John- References
son et al., 2003). The FAdV-1 based vaccine expressing the VP2 Abe, T., Nakamura, K., Tojo, T., and Yuasa, N. (2001). Gizzard erosion in
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protein of IBDV provided protection against challenge (Francois Adair, B.M., Todd, D., McFerran, J.B., and McKillop, E.R. (1986).
et al., 2004). The S1 gene of infectious bronchitis virus (IBV) Comparative serological studies with egg drop syndrome virus. Avian
incorporated into the genome of FAdV-8 was shown to provide Pathol. 15, 677–685.
protection (Johnson et al., 2003). Moreover, the chicken inter- Ahmad, M.U., and Burgess, G.W. (2001). Production and characterization of
feron gamma was successfully expressed in the FAdV-8 CFA40 monoclonal antibodies to fowl adenoviruses. Avian Pathol. 30, 457–463.
https://doi.org/10.1080/03079450120078635
strain (Johnson et al., 2000). An infectious clone of FAdV-9 was Alexander, H.S., Huber, P., Cao, J., Krell, P.J., and Nagy, E. (1998). Growth
generated and proved invaluable for genetic studies and vaccine characteristics of fowl adenovirus type 8 in a chicken hepatoma cell line.
development (Ojkic and Nagy, 2001). Deletion of a 2.4 kb region J. Virol. Methods 74, 9–14.
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and induced protection against the H5 subtype of highly patho- inclusion body hepatitis. Avian Dis. 51, 27–32. https://doi.org/10.1637
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Gay et al., 2015). Recently, an FAdV-9-based dual-site expression Anderson, K.P., and Fennie, E.H. (1987). Adenovirus early region 1A
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FAdV-1 and FAd-9, and likely all avian adenoviruses, lead to Asthana, M., Chandra, R., and Kumar, R. (2013). Hydropericardium
abortive infections in mammalian cells. However, these viruses syndrome: current state and future developments. Arch. Virol. 158,
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1999; Ojkic and Nagy, 2001; Corredor and Nagy, 2010b). FAdVs (1993). Evaluation of cell culture propagated and in vivo propagated
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For example, survival of C57BL/6 mice carrying B16 melanoma Barra, C., and Langlois, P. (2009). First step in characterization of cis-acting
and tumour regression increased upon intratumoural injections sequences involved in fowl adenovirus 1 (CELO) packaging and its
of FAdV-1 expressing the human interleukin 2 (Cherenova et effect on the development of a helper-dependent vector strategy. Virus
Genes 38, 46–55. https://doi.org/10.1007/s11262-008-0281-6
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FAdV-1 expressing the herpes simplex virus thymidine kinase adenovirus infection. Avian Pathol. 13, 119–126.
(TK) in combination with ganciclovir (Shashkova et al., 2005). Bartha, A., and Mészáros, J. (1985). Experimental infection of laying hens
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