A Case of Chronic Ulcerative Dermatitis and Feather Loss in a Hyacinth Macaw (Anodorhynchus hyacinthinus) from the Zoological Garden of Lisbon
M.C. Peleteiro, Jorge Correia , Margarida Cunha, and Ken Latimer
Departamento de Morfologia e Clínica, Faculdade de Medicina Veterinária, Rua Gomes Freire, 1199 Lisboa Codex, Portugal (Peleteiro and Correia); Lisbon Zoological Garden, Lisbon, Portugal (Cunha), and Department of Pathology, College of Veterinary Medicine, The University of Georgia, Georgia, Athens, (USA) (Latimer)
Abstract. Chronic dermatitis with feather loss was observed in a Hyacinth Macaw that died after shipment from Switzerland to the Lisbon Zoological Garden. The pattern of skin lesions and alopecia suggested feather picking and self mutilation. DNA in situ hybridization and microbiological culture were negative for viral, bacterial, and fungal infections. Major histological findings included chronic ulcerative dermatitis, hepatocellular necrosis, renal tubular necrosis, and serous pericarditis. The death of this bird probably resulted from a combination of shipping stress; hepatic, renal, and cardiac dysfunction; and chronic dermatitis.
Key Words: Avian, Psittacine, Hyacinth macaw, Anodorhynchus hyacinthinus, Chronic dermatitis, Hepatocellular necrosis, Pericarditis, Renal tubular necrosis
Introduction
Abnormalities of the avian integument are of diverse origin and may include metabolic diseases, infectious diseases, congenital disorders, and trauma-induced changes.1 The precise etiology of cutaneous disease in a given individual may be obscure and present a considerable diagnostic challenge to pathologists and zoological veterinarians. Definitive diagnosis of skin disease in affected birds often requires advanced histological techniques and microbiological culture. The following case report describes a hyacinth macaw with chronic ulcerative dermatitis and feather loss that died suddenly following translocation from Switzerland to Portugal.
Materials and Methods
Medical history: The tissues described in this report were obtained from a male Hyacinth Macaw (Anodorhynchus hyacinthinus). This bird was acquired by the Lisbon Zoological Garden from the Basel Zoological Gardens in Switzerland. The macaw was born and reared for the first months of life in the wild before being added to the zoological collection in Switzerland. The bird arrived in Portugal on the 16 April 1996 and died within 24 hours. At the time of death, the macaw was presumed to be 21 years old.
Tissue specimens and processing: The bird was necropsied and tissue specimens were collected for histopathologic examination. These tissues were fixed in 10% neutral buffered formalin, embedded in paraffin wax, and stained with haematoxylin and erythrosin. Replicate sections of skin were prepared for special stains, including Lillie-Twort for gram-positive and gram-negative bacteria, PAS for fungus, and Ziehl-Neelsen for acid-fast bacteria. Replicate liver sections were stained with Giemsa stain to detect bacteria, including Chlamydia sp. DNA in situ hybridization was performed on the liver sections to detect adenovirus, herpesvirus, avian polyomavirus virus, and psittacine beak and feather disease virus (PBFD) nucleic acid.2 DNA in situ hybridization also was done on feathered skin to detect PBFD and avian polyomavirus infections.
Microbiology: Fungal culture was done from skin scrapings using Sabouraud Dextrose Agar (Difco 0109-05). Agar preparations were inoculated and incubated at 37ºC for 3 days. Fungal colonies subsequently were identified using the API-ID 32 C system (BioMérieux 32 200).
For bacteriologic examination of intestinal contents, Hektoen Enteric Agar (Difco 0853-02) was inoculated and incubated at 37ºC for 24 hours. Specific identification of microorganisms was performed with the API 20E system (BioMérieux 20 100).
Results
Necropsy findings: The macaw’s body weight was 1.1 kg (average species body weight is approximately 1.355 kg). The skin had ulcerative to crusty lesions and pustules filled with yellow exudate. These lesions were observed over the inner wings, ventral surface, and thighs. Feather loss was observed in the same areas (Fig.1). The liver was variegated with pale brown foci. The pericardium was thickened with retention of serous fluid (serous pericarditis, Fig.2). The small intestine was congested. Congestion was most apparent within the duodenum and jejunum.
 |
 |
| Fig. 1. Hyacinth Macaw. Inner surface of wings and breast are devoid of feathers. |
Fig. 2. Hyacinth Macaw. Increased opacity of pericardium and pale brown foci within hepatic parenchyma. |
Histologic examination and special stains: The skin exhibited chronic ulcerative dermatitis and crust formation. The bed of the ulcers was covered with fibrin, heterophils, and detritus. Scattered aggregates of bacteria could be identified within the superficial layers of the crusts; however, organisms were not observed within the dermis. Ruptured feather follicles were noted occasionally and were associated with a keratin foreign body reaction in the dermis (Fig. 3). The dermis also had some areas of hyaline-type collagen fiber degeneration (Fig. 4).
 |
 |
| Fig. 3. Hyacinth Macaw, skin, H&E stain. Ruptured feather follicle with dermal keratin foreign body reaction. |
Fig. 4. Hyacinth Macaw, skin, H&E stain. Degenerative changes of dermal collagen fibers. |
In addition, multifocal perivascular inflammatory cell infiltrates were present throughout the dermis (Fig. 5). Lillie-Twort staining revealed rare microcolonies of gram-positive cocci within ruptured feather follicles and superficial crusts. DNA in situ hybridization of cutaneous tissues was negative for PBFD virus and avian polyomavirus. Acid-fast-stained skin sections were devoid of mycobacteria.
 |
| Fig. 5. Hyacinth Macaw, skin, H&E stain. Perivascular infiltrates of lymphocytes and plasma cells within the dermis. |
Small granules of brown pigment, resembling lipofuscin, were detected within a few hepatocytes. The liver sections also contained numerous shrunken, eosinophilic hepatocytes dispersed amongst normal cells. These changes suggested early hepatocellular degeneration and necrosis (Fig.6). Giemsa staining was negative for bacteria, including Chlamydia sp. DNA in situ hybridization of liver sections was negative for adenovirus, herpesvirus, polyomavirus, and PBFD virus infections. In the kidney, extensive tubular epithelial cell necrosis was observed (Fig.7).
 |
 |
| Fig. 6. Hyacinth Macaw, liver, H&E stain. Shrunken, eosinophilic hepatocytes among more normal cells |
Fig. 7. Hyacinth Macaw, kidney, H&E stain. Multifocal renal tubular necrosis is apparent. |
The lungs contained deposits of carbon, typical of anthracosis. The serosa of the small intestine was congested; however, mucosal changes were not observed.
Microbiology: Candida albicans was identified in the skin by fungal culture. Attempts to isolate Salmonella sp. from the intestinal contents were negative.
Discussion
The precise cause of death of this macaw was not apparent; however, both chronic and acute lesions were observed in histologic sections. Microscopically, the feather loss and skin lesions appeared to be a chronic disease process. The superficial microcolonies of gram-positive cocci and the Candida organisms identified in the skin were probably secondary pathogens of little clinical significance. Deep tissue invasion by these organisms was not observed. The pattern of the feather loss and skin lesions, in the absence of PBFD and avian polyomavirus infections, suggests that feather picking and self-mutilation were the cause of chronic skin disease. Generally, feather picking is observed most frequently in companion birds kept in relative isolation without the benefit of social interaction with owners or other birds.1
Diagnosis of feather picking disorders may be challenging. Although scattered perivascular dermal infiltrates were present in the dermis in some sections of skin, there was no histologic evidence of bacterial, fungal, or viral infection. It is undetermined, however, whether the mononuclear perivascular infiltrates in some skin sections were a cause or effect of feather picking and self-mutilation. Ultimately, the skin disease in this Hyacinth Macaw was presumed to have a psychological basis because there was no evidence of infectious, metabolic, hormonal, or neoplastic diseases in this individual that would be manifested as cutaneous lesions.1,3
The histologic changes within the liver, kidney, and heart were more acute than those observed in the skin and may have contributed more directly to the death of this bird. The reason for the hepatic and renal tubular necrosis is undetermined (but can be observed following toxin ingestion or drug treatment). Abnormalities in hepatic, renal, or cardiac function alone can cause death if the condition is severe and overwhelms the organ’s reserve capacity to sustain life. The death of this macaw most likely resulted from a fatal combination of hepatocellular necrosis, renal tubular necrosis, serous pericarditis, chronic debilitating skin disease, and stress of transportation.
References
1. Perry RA, Gill J, Cross GM: Disorders of the avian integument. Vet Clin N Am / Small Anim Pract 21:1307-1327, 1991.
2. Ramis A, Latimer KS, Niagro FD, Campagnoli RP, Ritchie BW, Pesti D; Diagnosis of psittacine beak and feather disease (PBFD) viral infection, avian polyomavirus infection, adenovirus infection, and herpesvirus infection in psittacine tissues using DNA in situ hybridization. Avian Pathol 23:643-657, 1993.
3. Cooper JE, Harrison GJ: Dermatology. In: Ritchie BW, Harrison GJ, Harrison LR (eds): Avian Medicine: Principles and Application. Wingers Publishing Inc. , Lake Worth, FL, 1994, pp. 607-639.
This Page Last Updated May 15, 1998 |