Psittacid Adenovirus-2 infection in the critically endangered orange-bellied parrot (Neophema chrysogastor): A key threatening process or an example of a host-adapted virus?

Abstract

Psittacid Adenovirus-2 (PsAdv-2) was identified in captive orange-bellied parrots ( Neophema chrysogastor ) during a multifactorial cluster of mortalities at the Adelaide Zoo, South Australia, and an outbreak of Pseudomonas aeruginosa septicaemia at the Tasmanian Department of Primary Industries, Parks, Water and Environment captive breeding facility, Taroona, Tasmania. This was the first time that an adenovirus had been identified in orange-bellied parrots and is the first report of PsAdv-2 in Australia. To investigate the status of PsAdv-2 in the captive population of orange-bellied parrots, 102 healthy birds from five breeding facilities were examined for the presence of PsAdv-2 DNA in droppings and/or cloacal swabs using a nested polymerase chain reaction assay. Additionally, eight birds released to the wild for the 2016 breeding season were similarly tested when they were recaptured prior to migration to be held in captivity for the winter. PsAdv-2 was identified in all breeding facilities as well as the birds recaptured from the wild. Prevalence of shedding ranged from 29.7 to 76.5%, demonstrating that PsAdv-2 is endemic in the captive population of orange-bellied parrots and that wild parrots may have been exposed to the virus. PsAdv-2 DNA was detected in both cloacal swabs and faeces of the orange-bellied parrots, but testing both samples from the same birds suggested that testing faeces would be more sensitive than cloacal swabs. PsAdv-2 was not found in other psittacine species housed in nearby aviaries at the Adelaide Zoo. The source of the infection in the orange-bellied parrots remains undetermined. In this study, PsAdv-2 prevalence of shedding was higher in adult birds as compared to birds less than one year old. Preliminary data also suggested a correlation between adenovirus shedding prevalence within the breeding collection and chick survival.

Genomic Characterisation of a Highly Divergent Siadenovirus (Psittacine Siadenovirus F) from the Critically Endangered Orange-Bellied Parrot (Neophema chrysogaster)

“…Avian siadenoviruses have been detected in wild birds from three continents—Antarctic [ 6 , 7 ], Australia [ 5 , 8 ], and Europe [ 9 ]—and in captive birds originating from Africa [ 9 , 10 ], Asia [ 10 , 11 ], the Indo-Pacific [ 10 , 11 ], including Australia [ 12 , 13 ], and South America [ 10 , 14 ]. They have evolved to infect a wide range of birds and have been detected in birds from the orders Columbiformes [ 5 , 15 ], Charadriiformes [ 7 ], Falconiformes [ 16 ], Galliformes [ 17 ], Passeriformes [ 9 , 12 , 18 ], Podargiformes [ 5 ], Psittaciformes [ 5 , 8 , 10 , 11 , 12 , 13 , 14 ], Sphenisciformes [ 6 ], and Strigiformes [ 5 ].…”

“…Avian siadenoviruses have been detected in wild birds from three continents—Antarctic [ 6 , 7 ], Australia [ 5 , 8 ], and Europe [ 9 ]—and in captive birds originating from Africa [ 9 , 10 ], Asia [ 10 , 11 ], the Indo-Pacific [ 10 , 11 ], including Australia [ 12 , 13 ], and South America [ 10 , 14 ]. They have evolved to infect a wide range of birds and have been detected in birds from the orders Columbiformes [ 5 , 15 ], Charadriiformes [ 7 ], Falconiformes [ 16 ], Galliformes [ 17 ], Passeriformes [ 9 , 12 , 18 ], Podargiformes [ 5 ], Psittaciformes [ 5 , 8 , 10 , 11 , 12 , 13 , 14 ], Sphenisciformes [ 6 ], and Strigiformes [ 5 ]. The majority of the sequence data for avian siadenoviruses is confined to small sequences (approximately 280 bp) of the DNA polymerase gene with full genome sequences limited to only nine unique viruses [ 3 , 6 , 7 , 8 , 14 , 16 , 17 ].…”

“…The epizootiology and pathogenicity of the PsSiAdV-F is perhaps the best studied of the adenoviruses infecting psittacine birds. It has a wide host range and has been detected in droppings and tissues from psittacine birds originating from their Pacific, Afro-Asian, and neotropical distributions [ 10 , 11 , 12 , 13 ]. The natural host species of this virus is not known, but the virus appears to have disseminated globally as the result of the pet trade in wild caught and captive-raised psittacine birds [ 10 , 12 ].…”

“…Most infections are subclinical and in the captive breeding population of the critically endangered orange-bellied parrot ( Neophema chrysogaster ), up to 77% of the birds tested can be shedding virus at any one time. It may also be widespread in other captive collections of psittacine birds [ 12 , 13 ]. It can also cause disease.…”

Identification of two novel adenoviruses in smooth-billed ani and tropical screech owl

“…Wild birds play an important role in the transmission and as reservoirs of various AdVs [27][28][29][30][31][32][33][34][35]. Habitat loss and fragmentation cause novel interactions between pathogens, hosts and the environment.…”