A description of the gross pathology of drowning and other causes of mortality in seabirds.

BACKGROUND: Mortality of seabirds due to anthropogenic causes, especially entrapment in fishing gear, is a matter of increasing international concern. This study aimed at characterising the gross pathology of seabirds that drowned in fishing nets and comparing it with that in other common causes of mortality. RESULTS: Post-mortem examinations were performed on 103 common guillemots, 32 razorbills, 37 shags and 5 great northern divers found stranded in Cornwall during 1981-2016. Pathology in birds that died in confirmed incidents of drowning in fishing nets (n = 95) was compared with that in cases of suspected drowning (n = 6), oil (n = 53) and polyisobutylene (PIB) (n = 3) pollution, adverse weather (n = 6) and stranding of unknown cause (14). The majority of drowned birds were in good nutritional state, freshly dead and approximately 50% had freshly ingested fish in their proximal gut. Principle lesions were: gross distention of the heart and major veins with dark blood, intensely congested, swollen and oedematous lungs which released white frothy fluid when excised, watery fluid in the air sacs that ranged from clear to deep red depending on state of carcase preservation. PIB-affected birds were in good nutritional state; their pathology was largely consistent with that in confirmed drowning cases; it is likely that drowning was the ultimate cause of death. Birds affected by oil, adverse weather or that stranded due to unknown cause were all in poor or emaciated condition, the mean body mass of the guillemots and razorbills being, respectively, 53 and 57% of those that drowned. They had little or no food in their alimentary tracts and many showed evidence of enteric inflammation, haemorrhage and ulceration. None had fluid in their air sacs and none showed significant cardio-respiratory system lesions. CONCLUSIONS: Drowned birds consistently showed a distinctive set of gross pathological lesions. When combined with contemporaneous observations, the pathology may be sufficient to permit a diagnosis of drowning, especially where a batch of freshly dead birds are examined. The observations in this study are likely to be of value when investigating stranding incidents, particularly where it is suspected that legislation aimed at protecting seabirds is not being complied with.

Bilateral Aural Adenocarcinoma in a Congo African Grey Parrot ( Psittacus erithacus erithacus).

A 28-year-old female Congo African grey parrot ( Psittacus erithacus erithacus) was evaluated because of a mass in the left external auditory meatus. Results of a computed tomography scan revealed an osteolytic left hemimandibular mass with irregular bone production and a soft tissue mass in the left external auditory meatus. Results of cytologic examination of fine needle aspirates of the hemimandible were interpreted as adenocarcinoma with reactive osteoblasts. The owner chose palliative treatment, and a debulking procedure was performed on the left external auditory meatus mass 52 days after initial presentation to control self-trauma. Euthanasia was elected 67 days after initial presentation because of poor prognosis associated with the development of bilateral masses of the external auditory meatus and lateral deviation of the mandible, findings that were confirmed by postmortem examination. Histopathologic results confirmed the diagnosis of bilateral aural adenocarcinoma with invasion of both temporal bones and hemimandibles.

Use of a Nitinol Wire Stent for Management of Severe Tracheal Stenosis in an Eclectus Parrot (Eclectus roratus).

A 25-year-old, female eclectus parrot (Eclectus roratus) presented for dyspnea 3 weeks after anesthesia and surgery for egg yolk coelomitis. Radiography, computed tomography, and tracheoscopy revealed multiple tracheal strictures spanning a length of 2.6 cm in the mid to distal trachea. Histopathologic examination revealed mild fibrosis, inflammation, and hyperplasia consistent with acquired tracheal strictures. Tracheal resection was not considered possible because of the length of the affected trachea. The strictures were resected endoscopically, and repeated balloon dilation under fluoroscopic guidance over the course of 10 months resulted in immediate but unsustained improvement. Computed tomography was used to measure the stenotic area. A 4 × 36-mm, custom-made, nitinol wire stent was inserted into the trachea under fluoroscopic guidance. After stent placement, intermittent episodes of mild to moderate dyspnea continued, and these responded to nebulization with a combination of saline, acetylcysteine, and dexamethasone. Multiple attempts to wean the patient off nebulization therapy and to switch to a corticosteroid-free combination were unsuccessful. The parrot eventually developed complications, was euthanatized, and necropsy was performed. Histologically, the tracheal mucosa had widespread erosion to ulceration, with accumulation of intraluminal exudate and bacteria, severe degeneration of skeletal muscle and tracheal rings, prominent fibrosis, and mild to moderate, submucosal inflammation. Clinicopathologic findings in this case suggested tracheomalacia, which has not been previously described in birds. Custom-made tracheal stents can be used for severe tracheal stenosis in birds when tracheal resection and anastomosis is not possible. Complications of tracheal stent placement in birds may include tracheitis and tracheomalacia. To our knowledge, this is the first report of tracheal stent placement in an avian species.

American kestrel (Falco spaverius) fledgling with severe bilateral periorbital swelling and infection with Mycoplasma buteonis, Avibacterium (Pasteurella) gallinarum, and Staphylococcus pasteuri.

Abstract: A female American kestrel (Falco spaverius) fledgling was found on the ground with a suspected trauma to the right eye and open-mouth breathing. During the first 2 days of hospitalization, the bird developed severe bilateral periorbital cellulitis, blepharoedema, and sinusitis. The periocular tissues of the right globe were devitalized and communicated with a fistula at the commissure of the right side of the beak. The blepharoedema of the left eye was aspirated and yielded a dark colored malodorous fluid, which was submitted for aerobic bacterial and Mycoplasma cultures. Results showed a mixed infection with Mycoplasma buteonis, Avibacterium gallinarum, and Staphylococcus pasteuri, all of which are not commonly isolated from birds of prey. With antimicrobial therapy, supportive care, and surgical debridement of the right periocular necrotic tissues and adhesed phthisical globe, the kestrel recovered from this severe mixed upper respiratory infection.

Macroscopic, histologic, and ultrastructural lesions associated with avian keratin disorder in black-capped chickadees (Poecile atricapillus).

An epizootic of beak abnormalities (avian keratin disorder) was recently detected among wild birds in Alaska. Here we describe the gross, histologic, and ultrastructural features of the disease in 30 affected adult black-capped chickadees (Poecile atricapillus). Grossly, there was elongation of the rhamphotheca, with varying degrees of lateral deviation, crossing, and gapping between the upper and lower beak. Not uncommonly, the claws were overgrown, and there was alopecia, scaling, and crusting of the skin. The most prominent histopathologic features in the beak included epidermal hyperplasia, hyperkeratosis, and core-like intrusions of necrotic debris. In affected birds, particularly those with moderate to severe beak overgrowth, there was remodeling of premaxillary and mandibular bones and various dermal lesions. Lesions analogous to those found in beaks were present in affected claws, indicating that this disorder may target both of these similar tissues. Mild to moderate hyperkeratosis occurred in other keratinized tissues, including skin, feather follicles, and, occasionally, sinus epithelium, but typically only in the presence of microbes. We did not find consistent evidence of a bacterial, fungal, or viral etiology for the beak lesions. The changes observed in affected birds did not correspond with any known avian diseases, suggesting a potentially novel hyperkeratotic disorder in wild birds.

Trichomonosis in free-ranging Eurasian collared doves (Streptopelia decaocto) and African collared dove hybrids (Streptopelia risoria) in the Caribbean and description of ITS-1 region genotypes.

We report the first documented occurrence of an outbreak of trichomonosis in a free-ranging small flock of Eurasian collared doves (Streptopelia decaocto) and African collared dove hybrids (Streptopelia risoria) in the Caribbean. In total, 18 birds were examined, including six African collared dove x Eurasian collared dove hybrids and 12 Eurasian collared doves. The affected age class consisted of adults. Sex distribution was equal. With a flock population size of 200 birds, mortality rate for the outbreak was estimated at 15-20%. Living birds were weak, showing evidence of mucus-stained beaks and open-mouth breathing. Caseous ulcerative yellow lesions were restricted to the upper gastrointestinal tract, with the exception of one bird, which had lesions in the upper gastrointestinal tract and in the liver. Ninety-four percent (17/18) of the affected birds had multiple extensive lesions. Lesions located on the roof of the oral cavity extended in 33% (6/18) into the orbit and in 11% (2/18) into the braincase. Using wet-mount microscopy, we were able to confirm Trichomonas gallinae in 22% (4/18) of the sampled animals. Fifteen samples submitted for PCR analysis tested positive. Sequence analysis of the internal transcribed spacer 1 (ITS-1) region of the ribosomal RNA (rRNA) revealed two distinct genotypes of Trichomonas. One sequence had 100% identity to the prototype T. gallinae isolate, whereas the other sequences had 98-100% identity to recently described Trichomonas-like parabasalid. On the basis of gross and histologic findings, along with the sequence results from the columbids in this report, it is likely that this Trichomonas-like parabasalid is pathogenic.

Radiation therapy of a malignant melanoma in a thick-billed parrot (Rhynchopsitta pachyrhyncha).

A male thick-billed parrot (Rhynchopsitta pachyrhyncha) was diagnosed with a malignant melanoma of the mandibular beak (gnathotheca). Surgical excision was impossible because of the location of the lesion; a combination of radiation therapy and oral antitumor drugs were used to treat the neoplasm. A whole-body computed tomographic scan showed evidence of metastasis in the lungs; the bird, therefore, was considered to have stage IV disease. Throughout the treatment period, the bird showed no clinical evidence of systemic disease. The bird was given 20 treatments of localized radiation therapy of 2.5 Gray (Gy) for a cumulative dose of 50 Gy. The bird was also treated with piroxicam and cimetidine orally from the time of diagnosis, throughout radiation therapy, and until its death. By the completion of radiation therapy, the initial lesion had decreased considerably in size. The bird survived 2.5 months after radiation therapy was completed but died of complications related to metastatic disease. Necropsy results revealed metastases throughout the body, including lesions in the lungs and liver. To our knowledge, this is the first report of localized radiation therapy and oral antitumor drugs being used to treat malignant melanoma in an avian patient. The radiation therapy did produce tumor response in the form of a reduction in size of the visible tumor.

Oral trichomonosis: Description and severity of lesions in birds in Spain.

Avian trichomonosis is a parasitic disease caused by the flagellated protozoan Trichomonas gallinae. Columbiformes are the reservoir host of the parasite, with high levels of infection, but also other domestic and wild birds from a variety of orders are susceptible to the infection and development of gross lesions. In this paper we describe the type and severity of lesions in wild birds in four avian orders (Accipitriformes, Falconiformes, Strigiformes and Columbiformes). A total of 94 clinical cases diagnosed of trichomonosis were selected for the categorization of their lesions in the upper digestive tract. The affected birds were classified into three different categories (mild, moderate and severe) based on size (in relation to the tracheal opening), depth and location of the lesions. Mild cases are those with small and superficial lesions far from the oropharyngeal opening; moderate cases possess larger and deeper lesions, and severe cases very large and deep lesions that impede swallowing or affect the skull. Mild lesions were found in 10.6 % of cases; moderate lesions were observed in 18.1 % of the birds and severe lesions in 71.3 %. Treatment outcomes in birds with either mild or moderate lesions were favorable, while severe lesions were related to poor body score, leading to death or euthanasia in most cases. A relationship between severe lesions and avian order was found, with a higher percentage of birds with this type in Falconiformes, Columbiformes and Strigiformes. Multifocal lesions were more frequent in Columbiformes and Falconiformes. In Strigiformes, 93.3 % of birds showed lesions in the upper jaw. This study seeks to further understanding of avian trichomonosis and to provide information that will be useful to veterinarians and related professionals for assessment, prognosis and treatment choice for these birds.

Mandibular squamous cell carcinoma in 2 psittacines.

A unilateral, malformed gnathotheca in a green-winged macaw (Ara chloropterus) was managed for 16 mo with periodic beak trims. Biopsy of the affected beak did not identify an underlying cause; however, at postmortem examination, a densely cellular neoplasm invaded the mandible from the beak, dissecting and effacing the cortex and trabecular bone and inciting periosteal proliferation. There was no evidence of metastasis. Neoplastic cells were strongly immunopositive for cytokeratin AE1/AE3, consistent with squamous cell carcinoma (SCC). A black-headed caique (Pionites melanocephalus) was presented with a similar clinical history, timeline, and gross appearance. Biopsy of the mandibular portion of the lesion resulted in a diagnosis of SCC. Medical management with toceranib at a palliative dose resulted in adverse side effects and was discontinued. Early diagnosis of mandibular SCC may allow for early intervention and development of treatment modalities. Our 2 cases suggest that the mandibular bone, not the beak, may be a preferred biopsy site in the diagnosis of mandibular SCC in psittacines.

Multiple fractures and luxations of palatofacial bones in a hawk-headed parrot (Deroptyus accipitrinus).

CASE DESCRIPTION A 16-year-old female hawk-headed parrot (Deroptyus accipitrinus) was evaluated because of beak trauma and difficulty eating. CLINICAL FINDINGS Physical examination revealed a lateral tissue protrusion in the left half of the oropharyngeal cavity ventral to the proximal aspect of the maxillary tomium as well as a small bony prominence on the left jugal arch. Range of motion of the beak appeared normal. A CT scan of the skull revealed rostroventral displacement of the left palatine bone from the maxilla and left lateral subluxation and lateral luxation of the pterygoid-parasphenoid-palatine complex and pterygoid-palatine articulation, respectively; and transverse fractures of the ipsilateral pterygoid bone, jugal arch, and palatine bone. TREATMENT AND OUTCOME Palatine bone displacement was reduced, and surgical fixation was achieved with an interfragmentary wire inserted through the rostral aspect of the affected palatine bone, maxilla, and rhinotheca. The lateral aspect of the wire was covered with dental acrylic. The wire was removed 2 weeks later owing to concerns over local vascular compromise and potential for infection. The bird started eating pelleted food approximately 3 months after surgery; full return of apparently normal beak function was regained by 10 months after surgery. CLINICAL RELEVANCE To the authors' knowledge, the described beak trauma and surgical approach have not previously been reported for Psittaciformes. Use of CT imaging was invaluable in diagnosing multiple traumatic bone abnormalities and planning surgical correction.

Cutaneous lymphosarcoma in a double yellow-headed Amazon parrot (Amazona ochrocephala oratrix).

A 2-year-old double yellow-headed Amazon parrot (Amazona ochrocephala oratrix) was presented for evaluation of a mass on the left wing. A second soft tissue swelling was present under the left mandible and a third in the right inguinal region. The bird had pale mucous membranes, but no other abnormalities were observed on physical examination. Results of the complete blood count and plasma biochemical profile were anemia and decreased total solids. Cytologic findings from fine needle aspirates of the 3 affected areas were nondiagnostic. Whole-body radiographs revealed focal soft tissue swellings. Doppler ultrasound demonstrated significant vascularity in the inguinal swelling; therefore, biopsy of the area was considered contraindicated. Because of the rapid and extensive progression of disease, the owners elected euthanasia. Gross postmortem examination revealed marked and generalized skin thickening. The spleen was slightly enlarged and the bone marrow prominent and gelatinous. The histologic diagnosis was lymphosarcoma, which involved the skin, spleen, and bone marrow. Immunohistochemistry results were consistent with lymphosarcoma of T-cell origin. This case presents an unusual cutaneous manifestation of lymphosarcoma in an Amazon parrot.

Sodium toxicity and pathology associated with exposure of waterfowl to hypersaline playa lakes of southeast New Mexico.

Cause of mortality was studied in waterfowl in hypersaline playa lakes of southeast New Mexico during spring and fall migration. Mortality was not common in wild ducks resting on the playas during good weather. However, when birds remained on the lakes for prolonged periods of time, such as during experimental trials and stormy weather, a heavy layer of salt precipitated on their feathers. Sodium toxicity was the cause of death for all experimental mallards housed on playa water and for 50% of the wild waterfowl found moribund or dead during the spring of 1995. Gross lesions included heavy salt precipitation on the feathers, ocular lens opacities, deeply congested brains, and dilated, thin-walled, fluid-filled cloacae. Microscopic lesions in the more severely affected birds included liquefaction of ocular lens cortex with lens fiber swelling and multifocal to diffuse ulcerative conjunctivitis with severe granulocytic inflammation, edema, and granulocytic vasculitis resulting in thrombosis. Inflammation similar to that seen in the conjunctiva occasionally involved the mucosa of the mouth, pharynx, nasal turbinates, cloaca, and bursa. Transcorneal movement of water in response to the hypersaline conditions on the playa lakes or direct contact with salt crystals could induce anterior segment dehydration of the aqueous humor and increased osmotic pressure on the lens, leading to cataract formation.

Candidiasis in cockatiel nestlings and mucormycosis in a pigeon.

Deaths of cockatiel nestlings caused by Candida albicans, and of a pigeon caused by air-sac infection with Absidia corymbifera, are described. Lesions in the cockatiels were pseudomembranes and ulcers in the mouth, esophagus, and crop. In the pigeon the air sacs were thickened and contained a grayish gelatinous exudate.

Osteosarcoma in an American robin (Turdus migratorius).

An osteosarcoma arising from the left hemimandible was diagnosed in an adult American robin (Turdus migratorius). Neoplastic spindle cells were observed extending away from foci of trabecular bone in dense sheets, occasionally within osteoid tissue. The variably pleomorphic spindle cells contained fibrillar, lightly basophilic cytoplasm, irregular, round to ovoid nuclei, and single or multiple small nucleoli. This is the first report of an osseous neoplasm in a wild passerine.

Acute toxicosis of budgerigars (Melopsittacus undulatus) caused by pyrolysis products from heated polytetrafluoroethylene: microscopic study.

An ultrastructural study was performed on the respiratory system of budgerigars (including 6 controls) which were acutely affected by inhalation of toxic fumes from heated polytetrafluoroethylene (PTFE pyrolysis products) or had survived fro 24 hours after a sublethal exposure. The controls were exposed to fumes from heated plan aluminum (ie, not coated with PTFE). The microanatomy of lungs of the controls was described and compared with that of lungs of the birds exposed to PTFE pyrolysates. The PTFE pyrolysates caused extensive, severe necrotizing and hemorrhagic pneumonitis. These lesions were associated with amorphous elongate conglomerates of particles which were similar to those isolated on membrane filters from fumes generated from heated PTFE--this supporting the hypothesis that the toxic principle in PTFE pyrolysates is at least, in part, related to generated particulates.

Acute toxicosis of budgerigars (Melopsittacus undulatus) caused by pyrolysis products from heated polytetrafluoroethylene: clinical study.

Polytetrafluoroethylene (PTFE), a synthetic polymer widely used as a nonstick surface in cookware, releases toxic pyrolysis products when exposed to excessive heat. Thirty-two budgerigars (Melopsittacus undulatus) were exposed to pyrolysis products of either heated PTFE cookware or plain aluminum cookware in a specially designed exposure chamber for given periods. Clinical signs were recorded and necropsies were done on all birds at the termination of each exposure period. The PTFE products caused acute respiratory distress and rapid death in many of the exposed birds. At necropsy, lesions were seen only in the respiratory tract--extensive pulmonary hemorrhage and congestion.

Apparent fatal snakebite in three hawks.

Based on histories and gross and histologic findings, snakebite was diagnosed in three dead raptors submitted for post-mortem examination from northern Florida and southern Georgia (USA). Two immature red-tailed hawks (Buteo jamaicensis) were found next to dead and partially eaten venomous snakes. An adult Cooper's hawk (Accipiter cooperii) was found adjacent to a den containing a cotton-mouth (Agkistrodon piscivorus) and an eastern diamondback rattlesnake (Crotalus adamanteus). Gross findings in all birds consisted of hemorrhage and gangrenous necrosis of one limb. Severe muscular degeneration was seen histologically.

Burrowing fly larvae (Philornis porteri) associated with mortality of eastern bluebirds in Florida.

We investigated mortality among nestling eastern bluebirds (Sialia sialis) in Polk and Highlands counties, Florida (USA) in 1999-2001. At least six species of maggots from three families of muscoid flies, Calliphoridae, Sarcophagidae, and Muscidae were found associated with the nestlings. Philornis porteri, the only species of obligate bird parasite collected, was found in the contents of two nests, in the ear canal and the musculature of the jaw of one nestling, and in the abdominal subcutis of another. This is the first record of bluebird parasitism by P. porteri. Although some nestlings were infested by tissue-invading fly larvae antemortem, the role of these maggots in the overall mortality was not clear.

Health effects following chronic dosing with tungsten-iron and tungsten-polymer shot in adult game-farm mallards.

Permanent approval of shot composed of tungsten-iron and tungsten-polymer for waterfowl hunting by the U.S. Fish and Wildlife Service was pending the results of the present study that examined the health and reproductive effects of the two shot types on mallards (Anas platyrhynchos) over a 150-day period. We collected data pertaining to the effects of tungsten-iron and tungsten-polymer shot on mortality, body weight, organ weight, tissue pathology, and shot erosion. Thirty-two bird groups (sexes equal) of adult mallards were dosed orally with eight #4 steel shot (control), eight #4 tungsten-iron shot, or eight #4 tungsten-polymer shot on days 0, 30, 60, 90, and 120 of a 150-day trial (26 January 1998 to 25 June 1998). An additional 12 mallards (sexes equal) were dosed orally with eight #4 lead shot (positive control) on day 0 of the study. All lead-dosed ducks died by day 25, whereas no ducks died in the other treatment groups. Significant liver hemosiderosis was present in all control and tungsten-iron-dosed males, in five of eight control and three of eight tungsten-iron-dosed females, and in one tungsten-polymer-dosed male examined. The rate of shot erosion was highest for tungsten-polymer shot (99%), followed by tungsten-iron (72%), and steel (55%) shot. Tungsten-iron or tungsten-polymer shot repeatedly administered to adult mallards did not have deleterious health effects during the 150-day trial based on mortality, body weights, organ weights, and histology of the liver and kidneys.

Hematological effects and metal residue concentrations following chronic dosing with tungsten-iron and tungsten-polymer shot in adult game-farm mallards.

The U.S. Fish and Wildlife Service required a chronic dosing study that assessed the health and reproductive effects of tungsten-iron and tungsten-polymer shot in adult game-farm mallards (Anas platyrhynchos) prior to granting permanent approval of the shot for waterfowl hunting. Herein, we present the effects of tungsten-iron and tungsten-polymer shot on various hematologic parameters and metal residue concentrations in the femur, liver, kidneys, and gonads. Thirty-two-bird groups (sexes equal) of adult mallards were dosed orally with eight #4 steel shot (control), eight #4 tungsten-iron shot, or eight #4 tungsten-polymer shot on days 0, 30, 60, 90, and 120 of a 150 day trial (26 January 1998 to 25 June 1998). An additional 12 mallards (sexes equal) received eight #4 lead shot (positive control) on day 0 of the study. Lead-dosed mallards had significantly decreased hematocrit, hemoglobin concentration, and whole-blood delta aminolevulinic acid dehydratase activity on day 7, as well as significant changes in a number of plasma chemistry parameters compared to ducks in the control, tungsten-iron, or tungsten-polymer groups. Mallards dosed with tungsten-iron or tungsten-polymer shot had occasional significant differences in hematocrit and plasma chemistry values when compared to control mallards over the 150 day period, but these changes were not considered to be indicative of deleterious effects. Low concentrations of tungsten were detected in gonad and kidney samples from males and females and in liver samples from females dosed with tungsten-polymer shot. Tungsten was also detected in femur samples from tungsten-polymer-dosed mallards. Higher concentrations of tungsten were detected in femur, liver, kidney, and gonad samples from tungsten-iron-dosed ducks. Tungsten-iron or tungsten-polymer shot repeatedly administered to adult mallards did not cause adverse hematological effects during the 150 day trial. Concentrations of tungsten in the femur, liver, kidneys, and gonads were generally higher in tungsten-iron-dosed ducks when compared to tungsten-polymer-dosed ducks.