Proventricular Dilatation Disease Associated with Avian Bornavirus in a Scarlet Macaw (Ara Macao)

Abstract

Abstract. A case of proventricular dilatation disease is described in a scarlet macaw (Ara macao) from clinical presentation to diagnosis with molecular methods. The initial clinical signs were depression progressing to head pressing over several days. A leukocytosis with toxic heterophil changes, hypoalbuminemia, and increased serum activity of aspartate aminotransferase and creatine kinase were present. Lead and zinc assays were within reference ranges, and results from Chlamydophila and polyomavirus testing were negative. Contrast-enhanced fluoroscopy revealed normal gastrointestinal transit times and motility as well as the presence of 2 small metallic foreign bodies in the ventriculus. The macaw was treated with antimicrobials, analgesics, vitamins E and B complex, force-feeding, and fluid administration with little improvement. Euthanasia was elected, and histologic examination of brain tissue revealed a perivascular lymphoplasmacytic infiltration, while the lungs had evidence of a fungal pneumonia. Tissue samples from the brain and proventriculus tested positive for the presence of Avian bornavirus genotype 2, while serology confirmed Avian bornavirus infection.Key words: Ara macao; Avian bornavirus; macaws; proventricular dilatation disease.Neuropathic gastric dilation or proventricular dilatation disease (PDD) has been variably described in the veterinary literature, and was initially referred to as macaw wasting syndrome in the early 1970s. 9 The terms ''neuropathic gastric dilatation'' and ''encephalomyelitis'' are in reference to the most commonly observed clinical and pathologic features of PDD. Historically, affected birds present with varying degrees of gastrointestinal signs, including anorexia, regurgitation, or presence of undigested seeds in feces, with or without neurologic signs (e.g., ataxia or obtundation). Frequently, the clinical signs are nonspecific and reflect disturbance in a number of different organs. 17,20,22 Although PDD appears to have a predilection for psittacines, it has been presumptively identified in toucans, Canada geese, and spoonbills.7 A viral etiology for the disease has been suspected for many years because of the epidemiologic evidence and the characteristic histopathologic changes observed in tissues of affected birds, but no specific virus was identified until the recent discovery of avian bornaviruses. 8,11,12 The present report describes a case of Avian bornavirus (ABV) in a scarlet macaw (Ara macao) exhibiting vague neurologic signs from initial presentation to identification and classification of the virus genotype.A 1.5-year-old male scarlet macaw weighing 0.95 kg was referred to the University of Wisconsin Veterinary Medical Teaching Hospital (UW-VMTH; Madison, Wisconsin) with a 2-week history of depression and loss of appetite. The bird was housed part of the time in a pet store, which sold and boarded birds of many different species. The bird had been acquired by the pet store owner 1 year earlier from a breeder and had been apparently healthy during this ...

Antigen tissue distribution of Avian bornavirus (ABV) in psittacine birds with natural spontaneous proventricular dilatation disease and ABV genotype 1 infection

“…13,27 Recently, more pronounced neurologic signs and central nervous system involvement (e.g., encephalitis) have been described more frequently in association with this disease. 1,13,15 There is mounting evidence that ABV infection is widespread in birds in North America, Australia, and Europe and can also be seen in apparently healthy animals. 5,19,25,32 A recent study demonstrated the presence of ABV antigen in a wide variety of cells in psittacine birds with natural ABV genotypes 2 and 4 infection.…”

Avian bornavirus genotype 4 recovered from naturally infected psittacine birds with proventricular dilatation disease in South Africa

“…The nature of the pathology in the birds described in this report, in conjunction with the pancytotropic tissue distribution of ABV antigen, would be consistent with that previously described for certain ABV genotype 4 isolates. Central nervous system lesions in these cases are also in line with the more pronounced central nervous system (CNS) pathology documented in recent reports Keller et al 2010;Ouyang et al 2009;Payne et al 2011;Wünschmann et al 2011).…”

Plasma protein, haematologic and blood chemistry changes in African grey parrots (Psittacus erithacus) experimentally infected with bornavirus

“…Specific reference ranges of the blood values for each parrot and for the group (Scope et al, 2002(Scope et al, , 2005(Scope et al, , 2006) allowed a very precise and individualized assessment even of minor changes. A reduced PCV as detected in P10 and P11 has also been described in several cases of natural bornavirus infection (Ridgway & Gallerstein, 1983;Joyner et al, 1989;Degernes et al, 1991;Keller et al, 2010). Gastrointestinal malabsorption was quoted as an explanation for the non-regenerative anaemia in birds suffering from PDD, as it is generally noted in starving birds (Suedmeyer, 1992;Gancz et al, 2010).…”