Adenovirus of psittacine birds: investigations on isolation and development of a real-time polymerase chain reaction for specific detection

Abstract

Liver samples of psittacine birds with a histological suspicion of an adenovirus infection, confirmed by electron microscopy examination, were subjected to virus isolation attempts using a heterologous cell culture system and a homologous cell culture system in the form of chicken embryo liver cells and psittacine embryo fibroblasts, respectively. Whereas isolation in chicken embryo liver cells failed, virus was isolated successfully in the psittacine embryo fibroblasts cell culture system. Molecular investigations identified the virus as a specific psittacine adenovirus (PsAdV). Additionally, on the basis of the hexon gene sequence data obtained, a real-time polymerase chain reaction (PCR) for specific detection of PsAdV was developed. To ensure an exclusive hybridization with PsAdV, selected primers were located within the variable L1 region of the hexon gene. Furthermore, the specificity of the real-time PCR was confirmed by investigation of a panel of different avian adenoviruses and unrelated DNA viruses. Using this PCR, the threshold cycle values obtained support the propagation of PsAdV in the homologous cell culture system in comparison with the chicken cell culture system. Moreover, the developed PCR represents a reliable method for specific and sensitive detection of PsAdV in clinical samples.

Detection of fowl adenovirus D strains in wild birds in Poland by Loop-Mediated Isothermal Amplification (LAMP)

“…They can be infectious for fish, reptiles, amphibians, birds, and mammals, and have been isolated from over 40 vertebrate species [1,2,6,7]. Wild birds with fowl adenovirus infections have been documented by Kumar [8], being presented in falcons [9][10][11], common buzzards [12], black kite [8], tawny frogmouths [13], psittacines [7,14,15] and pigeons [16]. It is possible that under some conditions, fowl adenoviruses may be more virulent in non-host-adapted species than in their typical ones [4].…”

Survey of captive parrot populations around Port Phillip Bay, Victoria, Australia, for psittacine beak and feather disease virus, avian polyomavirus and psittacine adenovirus

“…BFDV and APV cannot be differentiated by clinical presentation alone and, given that all three viruses produce a hepatopathy, a similar clinical pathology picture might be obtained for any of these viruses. Hence, highly sensitive PCR protocols have been developed to enable confirmation of infection with BFDV and APV, and there is more research into PsAdV protocols for detecting this virus …”

“…All three viruses are non‐enveloped, DNA‐based and have an icosahedral capsid . BFDV and APV are a problem worldwide, in both wild and captive populations, but the pathogenicity of adenovirus in psittacine populations remains unclear, although it is well established that this virus is significant among poultry flocks . Individual case reports suggest the same may be true for parrots …”

“…PsAdV has been described in many psittacine and non‐psittacine birds . This virus has been found in apparently healthy birds and in birds with very non‐specific clinical signs such as depression, anorexia and sudden death . Inclusion body hepatitis is not an uncommon finding during histopathological analysis of affected birds .…”

“…This virus has been found in apparently healthy birds and in birds with very non‐specific clinical signs such as depression, anorexia and sudden death . Inclusion body hepatitis is not an uncommon finding during histopathological analysis of affected birds . Cloacal haemorrhage, petechiations, splenic changes, dilated duodenum and proventriculus, enteritis, swollen kidneys, conjunctivitis and interstitial pneumonia have also been reported .…”