Arch Virol (2005) 150: 1933–1943
Phylogenetic analysis of the hexon loop 1 region
of an adenovirus from psittacine birds supports
the existence of a new psittacine adenovirus (PsAdV)
, H. Gerlach
, and H. M¨uller
Institute for Virology, Faculty of Veterinary Medicine,
University of Leipzig, Leipzig, Germany
Received December 9, 2004; accepted May 9, 2005
Published online June 22, 2005
Summary. Adenovirus infections in psittacine birds have been well known. Most
of these infections were caused by fowl adenoviruses (FAdV). In this study,
liver samples showing typical histological signs of an adenovirus infection were
collected from Poicephalus spp. with acute disease.A PCR amplifying the variable
loop 1 region of the hexon gene was developed using primers located in two
conserved pedestal regions. A PCR product of approximately 590 bp in size was
ampliﬁed and sequenced. The sequence obtained grouped outside of the FAdV
reference strains of the 12 serotypes as well as egg drop syndrome virus and turkey
adenovirus 3 indicating that a new avian adenovirus was detected. In comparison
to the FAdV reference strains, the percentage of identical nucleotides ranged
between 60.3 and 67.0 and that of identical amino acids (aa) between 51.3 and 61.0.
Furthermore, 37 unique aa exchanges were observed; out of these, 27 are located in
the 4 hypervariable regions of loop 1, which encode the serotype-speciﬁc epitops.
The g/c content, the isoelectric point and the charge of the ampliﬁed fragment,
however, are in the range as those of group I avian adenoviruses. It was proposed,
therefore, to designate this new adenovirus as psittacine adenovirus (PsAdV).
The classiﬁcation of the family Adenoviridae is currently under consideration.
Avian adenoviruses characterised by a common group-speciﬁc antigen  were
previously classiﬁed as group I  and still will represent the genus
Aviadenovirus. Prototypes of this genus are the fowl adenoviruses (FAdV) with 12
serotypes. Further group I avian adenoviruses have been isolated from turkey, duck
and pigeon, which can be differentiated by cross neutralization tests [3, 12, 34].