adenovirus in parrots

Adenoviruses are non-enveloped, double-stranded, linear, dna viruses in the family adenoviridae which all replicate with high fidelity in the host nuclei of vertebrates. adenovirus pathogens of commercial poultry and humans have been well characterised in terms of their genetic diversity, pathogenicity and the diseases they cause. while adenoviruses cause infections in a wide range of vertebrates, members of the genus atadenovirus, siadenovirus, and aviadenovirus predominantly infect avian hosts. the international committee on taxonomy of viruses (ictv) recognises five genera in the family with the majority of avian adenoviruses so far characterised belonging to the genus aviadenovirus for which the type species is fowl aviadenovirus a. this genus mostly affects gallinaceous birds with diseases of commercial significance in quail, poultry, ducks, geese, pheasants and turkeys. the predominance of avian adenoviruses in gamefowl and waterfowl has hinted towards an ancient host coevolution with the galloanserae, however there is widespread serological evidence in many wild birds such as albatross, cormorants and other avian neoavian lineages including pigeons, and parrots points to a more widespread host diversity. wide range of lesions have been associated with adenovirus infection in birds including conjunctivitis, splenitis, hepatitis, enteritis and a wide variety of other organs such as the central nervous system through the damage caused to endothelium. several recent studies on avian adenoviruses have encouraged us to re-visit previously proposed adenovirus evolutionary concepts. complete genomes and partial dna polymerase sequences of avian adenoviruses were extracted from ncbi and analysed using various software. genomic analyses and constructed phylogenetic trees identified the atadenovirus origin from an australian native passerine bird in contrast to the previously established reptilian origin. in addition, we demonstrated that the theories on higher at content in atadenoviruses are no longer accurate and cannot be considered as a species demarcation criterion for the genus atadenovirus. phylogenetic reconstruction further emphasised the need to reconsider siadenovirus origin, and we recommend extended studies on avian adenoviruses in wild birds to provide finer evolutionary resolution.