Endocrine pancreatic insufficiency secondary to chronic herpesvirus pancreatitis in a cockatiel (Nymphicus hollandicus)

Viral Diagnosis in Psittacine Birds: A Scientometric and Systematic Review of 47 Years

The first reports of viruses in psittacine birds date back to the early 1970s. Here, we elucidate the differences among these previous studies and the advances achieved. The objective of this study was to carry out a comprehensive review using both scientometric and systematic methods to analyze the evolution of published studies on viruses in psittacine birds up to 2022. The search descriptors "virus", "diagnosis", and "Psittaciformes" were used to find the articles of interest for this study. A total of 118 articles were manually selected, and the scientometric data were organized using the software VOSviewer® version 1.6.18. The present review revealed that: (i) on average, 2.5 articles/year on the diagnosis of viral infection in psittacine birds were published since 1975; (ii) the most productive research groups are concentrated in three countries: Australia, the United States, and Germany; (iii) the most important virus in psittacine birds is the Circovirus, which causes psittacine beak and feather disease; (iv) the diagnostic method of choice is polymerase chain reaction (PCR); and (v) the most studied psittacine birds were those in the Psittacidae family that were kept in captivity.

Avian Diabetes Mellitus: A Review

Diabetes mellitus (DM) is an uncommon, poorly documented metabolic disorder of birds. Extrapolating knowledge from DM in mammals is challenging because of marked differences in avian physiology and metabolism. A literature review from December 1991 to January 2022 identified 14 publications covering 16 diabetic birds, 63% (10/16) of which belonged to the order Psittaciformes with Ara as the predominant genus. No sex predilection was noted, but males generally presented at a younger age. Commonly reported clinical signs included polyuria 94% (15/16), polydipsia 88% (14/16), weight loss 75% (12/16), lethargy 63% (10/16), and polyphagia 38% (6/16). Diagnosis of DM was based on the presence of clinical signs and persistent hyperglycemia 100% (16/16), often with glucosuria 93% (13/14), response to insulin therapy 80% (8/10), and pancreatic pathology 90% (9/10). Specific treatment for DM was initiated in 14 patients, but blood glucose regulation for 6 months or longer was only achieved in 6 birds. Five of the regulated birds were managed with injectable long-acting insulin and 1 with oral glipizide combined with dietary modifications. However, glipizide yielded poor results in other cases, likely attributable to a lack of functional beta cells. Three diabetic birds progressed to remission. Treatment proved unsuccessful for 7 patients with a mean survival time of 36 days from diagnosis. One patient was lost to follow-up, and 2 were euthanized immediately following diagnosis. Histological examination of the pancreas frequently (90%, 9/10) revealed abnormalities including atrophy, fibrosis, and vacuolization of the endocrine islets with or without lymphoplasmacytic pancreatitis. Comorbidities, including hemosiderosis and infection, were common. This review suggests that birds diagnosed with DM are primarily affected by a type I diabetes as observed in dogs and humans. In contrast to mammalian species, avian DM is often associated with underlying disease and a complete clinical workup is essential to diagnose and address secondary disease conditions prior to initiating long-term insulin therapy.

Disseminated pancreatic adenocarcinoma in an eclectus parrot (Eclectus roratus)

CASE DESCRIPTION

A 15-year-old 0.412-kg (0.906-lb) sexually intact male eclectus parrot (Eclectus roratus) was evaluated because its owners found it lethargic and dyspneic at the bottom of its cage.

CLINICAL FINDINGS

The parrot was thin and had generalized muscle wasting, diffuse feather loss, pale mucous membranes, and melena. The coelomic cavity was distended and soft on palpation, with coelomic effusion suspected. Results of a CBC indicated leukocytosis with left shift heterophilia, including toxic heterophils, lymphopenia, and anemia. Plasma biochemical analyses revealed severe hyperamylasemia.

TREATMENT AND OUTCOME

Radiography revealed no evidence of a metallic foreign body but severe loss of coelomic detail, suggestive of a coelomic mass, coelomic effusion with coelomitis, or both. Ultrasonography and CT revealed severe accumulation of coelomic fluid; a large, heterogeneous, irregularly marginated, and moderately vascularized mass in the caudal aspect of the coelomic cavity; and multiple hepatic, coelomic, and pulmonary nodules. On the basis of a poor prognosis, the parrot was euthanized. Necropsy results confirmed exocrine pancreatic adenocarcinoma, with disseminated metastases in the liver, gastrointestinal tract, coelomic cavity, and lungs.

CLINICAL RELEVANCE

In birds, pancreatic adenocarcinoma is rarely reported but should be considered a differential diagnosis for hyperamylasemia, coelomic mass, coelomic effusion, or abnormal gastrointestinal signs, alone or in combination. Ultrasonography and CT can be useful in further evaluating such patients and should be considered in the diagnostic plan.

Acute Necrotizing Pancreatitis in a Yellow-naped Amazon Parrot ( Amazona auropalliata)

A 25-year-old female yellow-naped Amazon parrot ( Amazona auropalliata) was presented for an acute onset of lethargy, ptyalism, and regurgitation. Results of hematologic testing and plasma biochemical analysis revealed severe leukopenia and heteropenia with toxic heterophils and marked hyperamylasemia and hypoproteinemia, consistent with gastrointestinal dysfunction. Survey radiograph findings were suggestive of coelomic effusion. Results of a contrast-enhanced computed tomography (CT) scan revealed a tubular, irregularly marginated structure along the medial aspect of the duodenum, consistent with an inflamed pancreas. The bird died soon after CT imaging, and acute necrotizing pancreatitis and pancreatic coagulative necrosis were observed at necropsy. This report describes the use of a less-invasive modality such as CT to aid in the antemortem diagnosis of acute pancreatitis in a psittacine bird. Pancreatitis should be considered a differential diagnosis in birds with gastrointestinal signs and coelomic effusion visualized on radiography, and the observation of an enlarged inflamed pancreas in the absence of a defined pancreatic mass on CT.

Diabetes Mellitus With Concurrent Cerebellar Degeneration and Necrosis in a Domestic Goose ( Anser anser domesticus)

A 5-year-old sexually intact male Toulouse goose ( Anser anser domesticus) was presented for ataxia, polyuria, and polydipsia. The goose was cachectic and exhibited head tremors. Results of plasma biochemical analysis and point-of-care glucometry revealed persistent hyperglycemia. Despite supportive care and oral glipizide, the goose died within 48 hours of presentation. Necropsy revealed severe pancreatic atrophy and fibrosis with regionally extensive cerebellar encephalomalacia and generalized Purkinje cell degeneration and necrosis. On a wet basis, hepatic zinc concentration was determined to be twice the reference interval by atomic absorption spectroscopy. Based on these findings, the pancreatic insufficiency with secondary diabetes mellitus was attributed to chronic zinc toxicosis. Despite birds' relative resistance to high blood glucose concentrations, prolonged hyperglycemia is suspected to have caused selective Purkinje cell degeneration and necrosis by glial activation, mitochondrial dysfunction, and glutamate toxicity, which resulted in the clinically observed motor deficits. This is consistent with experimental diabetic rat models. This case highlights the need for further investigation of the complex pathophysiology of diabetes mellitus in birds.

Comparative occurrence of diabetes in canine, feline, and few wild animals and their association with pancreatic diseases and ketoacidosis with therapeutic approach

Diabetes mellitus (DM) is a chronic metabolic disorder in which blood glucose level raises that can result in severe complications. However, the incidence increased mostly by obesity, pregnancy, persistent corpus luteum, and diestrus phase in humans and animals. This review has focused on addressing the possible understanding and pathogenesis of spontaneous DM in canine, feline, and few wild animals. Furthermore, pancreatic associated disorders, diabetic ketoacidosis, hormonal and drug interaction with diabetes, and herbal remedies associated with DM are elucidated. Bibliographic search for the present review was done using PubMed, Scopus, and Google Scholar for articles on concurrent DM in small and wild animals. Persistent corpus luteal and pseudopregnancy in female dogs generate gestational DM (GDM). GDM can also be caused by extensive use of drugs/hormones such as glucocorticosteroids. Although many similarities are present between diabetic cats and diabetic humans which present islet amyloidosis, there was a progressive loss of β- and α-cells and the normal number of δ-cells. The most prominent similarity is the occurrence of islet amyloidosis in all cases of diabetic cat and over 90% of human non-insulin dependent DM Type-2. Acute pancreatic necrosis (APN) occurs due to predisposing factors such as insulin antagonism, insulin resistance, alteration in glucose tolerance, obesity, hyperadrenocorticism, and persistent usage of glucocorticoids, as these play a vital role in the progression of APN. To manage such conditions, it is important to deal with the etiological agent, risk factors, diagnosis of diabetes, and hormonal and drug interaction along with its termination with suitable therapy (herbal) protocols. It should be noted that the protocols used for the diagnosis and treatment of human DM are not appropriate for animals. Further investigations regarding diabetic conditions of pets and wild animals are required, which will benefit the health status of all animals health worldwide.

Histopathological and immunohistochemical study of exocrine and endocrine pancreatic lesions in avian influenza A experimentally infected turkeys showing evidence of pancreatic regeneration

In order to investigate the pancreatic lesions caused by the infection with either H7N1 or H7N3 low-pathogenicity avian influenza viruses, 28 experimentally infected turkeys were submitted for histopathology, immunohistochemistry, haematobiochemistry and real-time reverse transcriptase polymerase chain reaction after different days post-infection (DPI). The localization of viral antigen and the measurement of insulin and glucagon expression in the pancreas were assessed to verify the progression from pancreatitis to metabolic disorders, such as diabetes. At the early infection phase (4-7 DPI), a severe acute necrotizing pancreatitis was recognized. During the intermediate phase (8-17 DPI), a mixed acute/chronic change associated with regenerative ductular proliferation was observed. A loss of pancreatic islets was detected in most severe cases and viral antigen was found in the pancreas of 11/28 turkeys (4-10 DPI) with the most severe histological damage. In turkeys euthanized at 39 DPI (late phase), a chronic fibrosing pancreatitis was observed with the reestablishment of both the exocrine and the endocrine pancreas. Insulin and glucagon expression manifested a progressive decrease with subsequent ductular positivity. Haematobiochemistry revealed increased lipasemia in the first week post-infection and hyperglycaemia in the second, with a progressive normalization within 21 DPI. This study allowed the identification of progressive virus-associated exocrine and endocrine pancreatic damage, suggesting that influenza virus might be responsible for metabolic derangements. Moreover, it highlighted a remarkable post-damage hyperplastic and reparative process from a presumptive common exocrine/endocrine precursor. This potential regeneration deserves further investigation for its relevance in a therapeutic perspective to replace lost and non-functional cells in diabetes mellitus.

Lesions of the avian pancreas

Although not well described, occasional reports of avian exocrine and endocrine pancreatic disease are available. This article describes the lesions associated with common diseases of the avian pancreas reported in the literature and/or seen by the authors.