Histopathological Findings in the Cardiovascular System of Psittacidae in Routine Diagnostics

Samples of 363 Psittacidae were included in this study with a focus on cardiovascular diseases. These were identified in 28.9% of the animals, with pericarditis and/or epicarditis and myocarditis representing approximately half of all lesions and bacteria being the most common infectious cause. Cardiac lymphoma was only seen in 5 birds, whereas degenerative vascular lesions were diagnosed in 26.7% of the cases. Histopathology in the context of clinical findings and complementary examination results is the most useful tool for the evaluation of cardiac diseases.

Analysis of the B-Type Natriuretic Peptide and the Aminoterminal-Pro-B-Type Natriuretic Peptide in Different Parrot, Raptor and Owl Species

The B-type natriuretic peptide (BNP), a member of the natriuretic peptide family and a cardiac hormone, is produced mainly in the ventricular myocytes and released into the circulation due to mechanical stimuli during an increasing cardiac wall stretch. BNP has a significant role in the regulation of the cardiovascular system and body fluid. The concentration of this hormone and of the biologically inactive amino-terminal-prohormone in the blood plasma is a helpful diagnostic tool for detecting cardiovascular diseases in human medicine and can be used as a prognostic marker for the risk of mortality, whilst such a tool does not exist for avian medicine. To date, the amino acid sequence of BNP is not known for many of the species commonly presented in avian consultation. In this study, the amino acid sequence of BNP and the prepropeptide was described for 12 parrot species as well as 3 raptor and 3 owl species by polymerase chain reaction (PCR) after RNA isolation from the heart. The results showed a high similarity between the amino acid sequences in the mature peptide region of the BNP. The prepropeptide showed several differences between the examined species, some of them shared by closely related species.

Cardiac disease in the Spix Macaw (Cyanopsitta spixii): two cases

Cardiovascular disease in avian species, other than poultry, is being increasingly reported. In psittacine birds, atherosclerosis and congestive heart failure are the leading cardiovascular diseases, often resulting in multiorgan dysfunction and demise. The Spix's macaw (Cyanopsitta spixii) is arguably the most endangered psittacine species worldwide. We aimed to describe the gross and microscopic findings in two adult Spix's macaws wherein severe cardiovascular pathology resulted in sudden death. Bird 1 had pathologic findings consistent with fibrinoheterophilic vegetative pulmonic valvular endocarditis with luminal obliterative thrombosis, myocarditis and epicarditis, myocardial fibrofatty infiltration and cardiomyocyte loss, as well as generalized septicaemia. Microbiological analysis yielded Pantoea septica from the intestines and Acinetobacter baylyi from the cerebrum. Bird 2 had changes suggestive of right brachiocephalic coarctation-like obliterative arteriopathy. The latter is a novel cardiovascular pathology in avian species, and its severity and extent likely led to acute decompensation of pre-existing cardiac disease. These results add to the body of knowledge on avian cardiovascular pathology and may aid in veterinary medical decisions on caged birds, including those part of ex situ conservation efforts.

Cardiac Lesions of Natural and Experimental Infection by Parrot Bornaviruses

Lymphoplasmacytic inflammation associated with bornavirus N protein occurs in the epicardial ganglia, myocardium and endocardium of birds diagnosed with proventricular dilatation disease (PDD). These pathological findings suggest that sudden death in psittacine birds might stem from cardiac compromise due to parrot bornavirus (PaBV) infection. Therefore, we investigated cardiac lesions in cases of PDD, searching databases from 1988 to 2019, and reviewed three experimental studies of PaBV infection. Fifty cases of PDD in birds infected naturally with PaBV and 27 cases of PDD in birds infected experimentally with PaBV (all having descriptions of inflammatory cardiac lesions) were reviewed. For each case, five regions of the heart were evaluated by light microscopy and immunohistochemistry (IHC). These regions were the epicardial ganglia/nerves, the endocardium, the myocardium, the Purkinje fibres and the great vessels. Sudden death was documented in 17/50 naturally infected cases, while 23/50 had digestive signs, and only 12/50 had neurological signs. Grossly, only five naturally-infected and five experimentally-infected cases had cardiomegaly or hydropericardium. Epicardial ganglioneuritis was the most consistent microscopical finding in natural (46/50) and experimental cases (26/27), followed by myocarditis (34/50) for naturally-infected and endocarditis for experimentally-infected birds (6/27). PaBV-2 antigen was detected most frequently by IHC in the epicardial ganglia (54/77) compared with the other tissues. This retrospective study demonstrates the presence of PaBV protein and inflammation in the heart of birds infected with PaBV and suggests a link between PaBV and cardiac disease and sudden death in psittacine birds.