Seeing beyond a Dilated Proventriculus: Diagnostic Tools for Proventricular Dilatation Disease in Psittacine Birds

SIMPLE SUMMARY: Proventricular dilatation disease (PDD) is a life-threatening neurological disease that affects several psittacine species, including endangered ones. Recognizing which tools are available and which ones are more appropriate for different antemortem and postmortem situations is crucial for an effective and quick diagnosis. Here, we review the main diagnostic strategies for PDD in psittacine birds, which can help veterinary clinicians and diagnosticians to offer the best approaches regarding diagnostic-oriented biotechnologies for pet owners, zoos, rehabilitation centers, breeding facilities and other institutions working with ex situ avian conservation. A combination of different strategies can increase the success of diagnostic outcomes. ABSTRACT: Proventricular dilatation disease (PDD) is a life-threatening neurological disease caused by parrot bornaviruses (PaBVs) that affects several species worldwide. PDD can be clinically manifested as either a central nervous system condition or a gastrointestinal condition if the nerves and ganglia of the gastrointestinal tract are compromised. We intend to provide a concise review for veterinary clinicians and diagnosticians with focus on the main tools available for PDD diagnosis, including gross and histopathology, immunohistochemistry, molecular techniques and serology. We suggest that a combination of different strategies can increase the success of diagnostic outcomes, as tools such as reverse transcription polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA) can be implemented for identification of bornaviral infections in live patients, and gross pathology, histopathology, immunohistochemistry and RT-PCR can provide reliable results for postmortem diagnosis of PDD.