Investigation into clinicopathological and pathological findings, prognosis, and aetiology of lorikeet paralysis syndrome in rainbow lorikeets (Trichoglossus haematodus).

OBJECTIVE: To report the temporal and spatial distribution of rainbow lorikeets presenting with lorikeet paralysis syndrome (LPS) and their clinicopathologic and pathologic findings, exposure to toxins, and response to treatment. METHODS: Records of lorikeets admitted in 2017 and 2018 to facilities in south-east Queensland (QLD) were reviewed and LPS and non-LPS cases were mapped and their distribution compared. Plasma biochemistries and complete blood counts were done on 20 representative lorikeets from south-east QLD and Grafton, New South Wales (NSW). Tissues from 28 lorikeets were examined histologically. Samples were tested for pesticides (n = 19), toxic elements (n = 23), botulism (n = 15) and alcohol (n = 5). RESULTS: LPS occurred in warmer months. Affected lorikeets were found across south-east QLD. Hotspots were identified in Brisbane and the Sunshine Coast. Lorikeets had a heterophilic leucocytosis, elevated muscle enzymes, uric acid and sodium and chloride. Specific lesions were not found. Exposure to cadmium was common in LPS and non-LPS lorikeets. Treated lorikeets had a 60-93% See Table 2 depending on severity of signs. CLINICAL SIGNIFICANCE: The primary differential diagnosis for lorikeets presenting with lower motor neuron signs during spring, summer and autumn in northern NSW and south-east Queensland should be LPS. With supportive care, prognosis is fair to good.

Inconsistent efficacy of water-soluble amphotericin B for the treatment of Macrorhabdus ornithogaster in a budgerigar (Melopsittacus undulatus) aviary.

OBJECTIVE: To assess the efficacy of a commercially available in-water amphotericin B treatment for Macrorhabdus ornithogaster. DESIGN: Clinical treatment trial. METHODS: Faecal shedding of 16 naturally infected budgerigars (Melopsittacus undulatus) was monitored while they were being treated using in-water amphotericin B, as per the manufacturer's instructions, for 10 days. Any birds that remained positive after 10 days received a further 10 day course of treatment. All birds were rechecked 16 days after the end of the second treatment period. RESULTS: At the conclusion of treatment, 11 birds had stopped shedding M. ornithogaster, and 5 birds were still shedding. Sixteen days after the conclusion of the second treatment period, four birds that were negative after 10 days of treatment were shedding again, and two of the birds that were treated for 20 days were shedding. In addition, one bird from each treatment group died after treatment and before follow-up testing. CONCLUSION: These findings represent a 36% treatment failure, suggesting that treatment with the commercially available, water-soluble amphotericin B has inconsistent efficacy against M. ornithogaster in some budgerigars in Australia and is not effective for eliminating it from budgerigar aviaries.

Humeral air sac cystadenocarcinoma in a rainbow lorikeet (Trichoglossus moluccanus).

BACKGROUND: A 17-year-old female rainbow lorikeet (Trichoglossus moluccanus) was presented for a swelling over the right proximal humerus and an inability to fly. CASE REPORT: Radiographs revealed a markedly osteoproductive and moderately osteolytic lesion of the proximal left humerus with marked associated soft tissue swelling. Biopsy of the proximal humerus was consistent with an air sac cystadenocarcioma. The bird's condition deteriorated over 25 days after initial presentation and it developed a respiratory wheeze, tail bob, tachypnea and died. On postmortem examination, the bird was found to have an air sac cystadenocarcinoma associated with the proximal humerus, extending into the thoracic cavity through a network of fibrous sheets and displaying infiltration into the lung tissue bilaterally. CONCLUSION: This is the first report of a humeral air sac cystadenocarcinoma in a lorikeet and it builds on our understanding of the species affected by avian neoplasia.

Compensatory gastric stretching following subtotal gastric resection due to gastric adenocarcinoma in a diamond python (Morelia spilota spilota).

CASE REPORT: A 7-year-old male diamond python (Morelia spilota spilota) presented with a 2-month history of anorexia and a discrete intracoelomic mass, approximately 15 cm in length, located 90 cm from the head and approximately two-thirds of the snout to vent length. Physical examination determined the mass was likely to be stomach, testes or the right kidney. Radiographs showed a soft tissue opacity mass in the region of the stomach; fine needle aspirate demonstrated cellular debris admixed with bacteria and degenerate heterophils. Exploratory coeliotomy revealed a gastric mass involving 90% of the length of the stomach, partially occluding the gastric lumen. A subtotal gastrectomy was performed; the neoplastic tissue was removed with 2 cm margins, leaving 1 cm of stomach wall and the pyloric sphincter caudally that was anastomosed to the oesophagus. Four large nematodes were found within the necrotic lumen of the mass tightly adhered to the gastric mucosa. Ascarid nematodes were identified morphologically and further confirmed by molecular diagnostics as Ophidascaris spp. Histopathological evaluation of the excised mass revealed a gastric adenocarcinoma. Postoperatively the snake suffered from gastrointestinal dysfunction and maldigestion and was managed with slurry feeding for month. Three months postoperatively the snake was gaining weight, eating without assistance and digesting whole prey, which was incrementally increased in size. Gastroscopy 6 months postoperatively revealed the presence of a functional stomach with a functional pyloric sphincter and 8.5 cm of gastric mucosa caudal to the anastomosis between the oesophagus and stomach. CONCLUSION: This is the first report of almost complete subtotal gastric resection in an Australian python, with evidence of compensatory gastric stretching resulting in a functional stomach.

Why did severe feather pecking and cannibalism outbreaks occur? An unintended case study while investigating the effects of forage and stress on pullets during rearing.

This 2 × 2 factorial experiment aimed to investigate the effects of stimulating foraging behavior from wk 6 and imposed stress at wk 16 on the development of severe feather pecking (SFP) in chickens reared for free-range egg production. Non-beak-trimmed ISA Brown chicks were purchased at one day old and floor-reared on wood shavings. From wk 6, straw was provided daily in dispensers (Forage vs. No forage) to stimulate foraging. At wk 15, there were 16 pens of 50 pullets. "Stressors" were applied to half the pens in wk 16 via combined transport, relocation, and mixing (TRM) of pullets, simulating activities around transfer from the rearing to egg-laying farm (TRM vs. Not TRM). Range access was permitted from wk 21. Behavior, plumage damage (PD), growth, egg production, feed use, injuries, and mortalities were recorded, along with litter moisture and pH. In wk 26, an SFP outbreak commenced. By wk 34, PD was worse in south- than north-aspect pens (P < 0.001). Further, PD was more affected by side of the shed than the experimental treatments. In wk 30, an outbreak of injurious pecking (IP) commenced in the 4 TRM-treatment pens on the south side, with IP deaths almost 3 times more common in the Forage+TRM than No forage+TRM treatment. We suggest factors associated with a 13-day rainfall event that occurred in late winter predisposed the flock to SFP. While multiple factors such as winter cold, muddy ranges, damp floor litter with elevated pH, among others coincided, hens were clearly more impacted in south- than north-aspect pens. Once initiated, SFP possibly spread via social learning, and by wk 40, ∼98% of hens had PD. Interestingly, the IP outbreak was related to a combination of factors (stressors?), such as being housed in colder, damper south-aspect pens (note: southern hemisphere), having added Forage, and TRM. These unexpected relationships could help direct future research to identify the specific factors involved in the causation of SFP and IP/cannibalism outbreaks.

A novel herpesvirus associated with respiratory disease in Bourke's parrots (Neopsephotus bourkii).

A novel herpesvirus infection in nine Bourke's parrots (Neopsephotus bourkii, formerly Neophema bourkii) housed in an outdoor aviary comprised of multiple species of birds was diagnosed based on histopathology, electron microscopy and polymerase chain reaction (PCR). Clinical signs in the parrots included anorexia, ruffled feathers, depression, loss of weight and respiratory distress. The most common gross lesions were moderately congested and oedematous lungs and a mild fibrinous exudate in the air sacs and lumen of the trachea. Histological examination revealed mild to severe bronchopneumonia and airsacculitis with syncytial cells containing eosinophilic intranuclear inclusion bodies in most birds. Other less frequent changes included tracheitis, syringitis, sinusitis, rhinitis, otitis media and conjunctivitis. Attempts to culture the virus in chicken embryos and chicken embryo liver cells were unsuccessful. Examination by transmission electron microscopy of syncytial cells from the lungs of two birds revealed intranuclear virus particles typical of the family Herpesviridae. DNA from a novel herpesvirus was amplified from lung tissue by PCR using degenerate primers derived from conserved avian herpesvirus sequences. The virus belongs in the genus Iltovirus of the Alphaherpesvirinae subfamily. It is not closely related to Psittacid herpesvirus 1 that causes Pacheco's disease but does group phylogenetically with a clade of herpesviruses that cause respiratory disease in a number of avian species. The proposed name for this herpesvirus is Psittacid herpesvirus 3.

Fatal columbid herpesvirus-1 infections in three species of Australian birds of prey.

We document columbid herpesvirus-1 (CoHV-1) infection in two barking owls (Ninox connivens), a powerful owl (Ninox strenua) and an Australian hobby (Falco longipennis). Antemortem signs of infection were non-specific and the birds either died soon after they were identified as ill or were found dead unexpectedly. Gross postmortem findings were also not specific. Microscopically, marked to massive splenic and hepatic necrosis with the presence of eosinophilic inclusion bodies in remaining splenocytes and hepatocytes was found in all birds. Herpesvirus virions were identified in liver sections from one of the boobook owls by electron microscopy. Using CoHV-1-specific primers and polymerase chain reaction, CoHV-1 DNA was amplified from tissue samples from all birds. A comparison of these sequences to previously reported sequences of CoHV-1 found them to be identical or to vary by a single base pair. These findings increase the number of known species of birds of prey that are susceptible to CoHV-1 infection and indicate that rock pigeons (Columbia livia) should not be included in the diet of captive Australian birds of prey.

Humoral response to Mycobacterium avium subsp. avium in naturally infected ring-neck doves (Streptopelia risoria).

Creation of a reliable and easy to use serologic test would greatly improve ante mortem diagnosis of Mycobacterium avium subsp. avium and aid in the control of avian mycobacteriosis, particularly in captive birds. In order to determine whether serodiagnostics could be of value in testing ring-neck doves (Streptopelia risoria) for M. a. avium infection, Western blot analysis was used to assess the humoral response of ring-neck doves exposed to M. a. avium, and to evaluate whether an association could be made between the humoral response and necropsy findings, histopathology, culture, and PCR testing. Western blot results were examined for reactivity patterns associating humoral response with infection status, severity and type of lesions (diffuse vs. multifocal granulomatous inflammation) and phenotype (white vs. non-white). A sensitivity of 88.24% and a specificity of 100% were achieved utilizing Western blot analysis to detect M. a. avium infection in ring-neck doves, offering a negative predictive value of 93% and a positive predictive value of 100%. While Western blot analysis results did not reflect lesion severity, lesion type did partially correspond with the humoral response. The findings of the present study indicate that serologic testing can be used as a valuable ante mortem screening tool for identifying ring-neck doves infected with M. a. avium.

Detection and heterogeneity of herpesviruses causing Pacheco's disease in parrots.

Pacheco's disease (PD) is a common, often fatal, disease of parrots. We cloned a virus isolate from a parrot that had characteristic lesions of PD. Three viral clones were partially sequenced, demonstrating that this virus was an alphaherpesvirus most closely related to the gallid herpesvirus 1. Five primer sets were developed from these sequences. The primer sets were used with PCR to screen tissues or tissue culture media suspected to contain viruses from 54 outbreaks of PD. The primer sets amplified DNA from all but one sample. Ten amplification patterns were detected, indicating that PD is caused by a genetically heterogeneous population of viruses. A single genetic variant (psittacid herpesvirus variant 1) amplified with all primer sets and was the most common virus variant (62.7%). A single primer set (23F) amplified DNA from all of the positive samples, suggesting that PCR could be used as a rapid postmortem assay for these viruses. PCR was found to be significantly more sensitive than tissue culture for the detection of psittacid herpesviruses.

Isolation and characterization of an avian isolate of Encephalitozoon hellem.

Members of the phylum Microspora are a group of unusual, obligate intracellular eukaryotic parasites that infect a wide range of hosts. However, there are a limited number of microsporidial infections reported in avian hosts, and no parasite species has been defined as an avian pathogen. A microsporidian organism was recovered from the droppings of a clinically normal peach-faced lovebird (Agapornis roseicollis) and established in in vitro culture. Intermittent parasite spore shedding was documented over a 2-month period using calcofluor M2R staining of cloacal swabs. The organism was identified as Encephalitozoon hellem based on protein and antigenic profiles and molecular sequencing of the small subunit and internal transcribed spacer regions of the ribosomal RNA gene.

Viremia, virus shedding, and antibody response during natural avian polyomavirus infection in parrots.

OBJECTIVE: To determine rapidity of spread and onset and duration of viremia, virus shedding, and antibody production in parrots naturally infected with avian polyomavirus (APV). DESIGN: Case series. ANIMALS: 92 parrots in 2 aviaries. PROCEDURE: Blood samples were obtained from parrots naturally exposed to APV during a 3- to 4-month period for determination of serum virus neutralizing antibody and detection of viral DNA. Nestlings from the next year's hatch were monitored for APV infection. RESULTS: The first indication of inapparent infection was viremia, which developed simultaneously with or was followed within 1 week by cloacal virus shedding and antibody production. Cloacal virus shedding continued after viremia ceased. During viremia, viral DNA was detected continuously in blood samples. Viral DNA was detected in serial cloacal swab specimens in most birds, but it was detected inconsistently in 6 birds and not detected in 3 birds, even though these birds were viremic. Duration of cloacal virus shedding was < or = 4.5 months. In 1 aviary, prevalence of infection was 88% and dissemination of virus through the 3-room building required 4.5 months. In the second aviary, a single-room nursery, prevalence of infection was > or = 90%. For all affected birds, infection could be detected 18 days after the first death. CONCLUSIONS AND CLINICAL RELEVANCE: If a single sampling is used for polymerase chain reaction detection of viral DNA, blood and cloacal swab specimens are required. In nestling nonbudgerigar parrots, cloacal virus shedding may persist for 4.5 months. Management protocols alone are sufficient to prevent introduction of APV into a nursery.

Respiratory medicine of cage and aviary birds.

Respiratory diseases are a relatively common cause of illness and death in cage birds. A diagnostic algorithm is provided based on history, physical examination, and ancillary diagnostic findings that assist clinicians in determining the cause of a bird's respiratory disease. Also included are detailed descriptions of the common respiratory diseases of cage birds and their treatment.

Obstructive respiratory disease in prairie dogs with odontomas.

The clinical manifestations of odontomas in prairie dogs are described. Familiarity with this disease is important because it is common, and the signs of this disease mimic other respiratory disorders.

Avian polyomavirus infection and disease in a green aracaris (Pteroglossus viridis).

Avian polyomavirus (APV) is one of the most significant pathogens of domestically raised psittacine birds (parrots). One or more APVs are suspected to infect nonpsittacine cage birds, but the relationship of these viruses to the APV infecting parrots remains unclear. In this report, for the first time, we fully document an APV infection in a nonpsittacine cage bird, a green aracaris (Pteroglossus viridis). Grossly, this bird evidenced generalized hemorrhage. Histologically, there was severe hepatic necrosis, splenic necrosis, and the presence of lightly basophilic to clear pannuclear inclusion bodies and karyomegaly in splenocytes and renal mesangeal cells, all characteristic lesions of APV infection in parrots. APV DNA was amplified directly from the liver by polymerase chain reaction and sequenced. The virus differed from the original APV sequence by only 24 base pairs (0.48% of the genome), demonstrating that it is a variant of the APV. A serologic survey of the remaining birds in the aviary demonstrated anti-APV antibody in two cockatoos, two cockatiels, a laughing kookaburra, a Lady Ross turaco, and five zebra finches. The remaining green aracaris was seronegative. The sequence and serologic data suggest that the APV that infected the green aracaris originated in a parrot and was capable of infecting birds from at least four orders.

Genetic diversity in twenty variants of the avian polyomavirus.

To determine if different pathotypes of the avian polyomavirus (APV) exist and to compare the genomes of APVs originating from different geographic areas, dates, and species of birds, the partial sequences of 18 APVs were determined. New viral sequences were compared with three published APV sequences. Two of the new viruses had identical sequences. Forty point mutations were found at 31 loci. A 27-bp deletion was found in the VP2 and VP3 open reading frames of one virus. A duplication of the putative origin of replication and adjacent enhancer region was previously reported in one APV. Smaller duplications involving the origin in one APV and a second enhancer region in another were discovered. All duplications were in tissue culture-adapted viruses, suggesting they occurred during the isolation process. Excluding duplications and the deletion, maximum variation between viruses was small (11 bp). A maximum parsimony tree was constructed that contained three major branches. The three earliest isolates were on separate branches. The European viruses were confined to branch I, but APVs from the United States were on all three branches. Lovebird, budgerigar, and macaw APVs were also on each of the three branches, suggesting that species-specific pathotypes have not developed. Most nonsynonymous mutations occurred in a small portion of the VP2 and VP3 open reading frames, demonstrating a selection for these mutations. That a glycine at VP2 221 will inhibit virus replication in chicken embryo fibroblasts (CEFs) has been previously reported. In contrast, six of seven of the new APVs isolated in CEFs had a glycine at VP2 221.

Partial tracheal obstruction due to chondromas in ball pythons (Python regius).

Over a 9-mo period, three adult ball pythons (Python regius) (one male, two females) were evaluated for severe dyspnea. Partial obstructions of the tracheal lumen were identified radiographically and/or visualized with a 3.0-mm rigid laparoscope inserted into the tracheal lumen in all three snakes. Administration of systemic antibiotics and nebulization resulted in partial improvement of the dyspnea. In two snakes, the tracheal lesions were removed with a rigid laparoscope and a flexible biopsy instrument inserted into the tracheal lumen. The other snake died and was necropsied. Histologically, the lesions from two snakes were determined to be benign chondromas. The chondromas were composed of a variably disorganized chondroid matrix populated by quiescent, normal-appearing chondrocytes within lacunae, although the chondrocytes were increased in density compared with normal hyaline cartilage and contained rare mitotic figures. The tracheal masses in one snake grew by expansion, not invasion, and were focally continuous with a mineralized cartilage tracheal ring, suggesting a benign nature. This is the second report of tracheal chondroma in ball pythons. Tracheal chondromas are exceedingly rare in humans and domesticated animals, suggesting a possible predisposition of ball pythons for this neoplasm.

A serologic survey for avian polyomavirus and Pacheco's disease virus in Australian cockatoos.

Sera collected from wild and captive Australian cockatoos and other psittacine species (n = 411) were tested for antibodies to avian polyomavirus (APV) and Pacheco's disease virus (PDV). Of 144 wild sulphur-crested cockatoos (Cacatua galerita) sampled at three regions in New South Wales (NSW) 96 (64.4%) birds had positive (>/= 1:32) neutralizing antibody titres to avian polyomavirus (range 1:32-1:2048). Two of 17 wild long-billed corellas (Cacatua tenuirostris) were also APV-antibody positive. However, no samples from 107 wild galahs (Eolophus roseicapillus) were positive for neutralizing antibody to APV. Sera were also collected from captive psittacine bird flocks from NSW, Tasmania, Victoria, and Western Australia. In a mixed aviary of cockatoos and lorikeets, APV antibody was detected in sera from sulphur-crested cockatoos, Major Mitchell's cockatoos (Cacatua leadbeateri), a white-tailed black cockatoo (Calyptorhynchus baudinii latirostris), a red-tailed black cockatoo (Calyptorhynchus magnificus) a single galah, a rainbow lorikeet (Trichoglossus haematodus), and a scaley-breasted lorikeet (Trichoglossus chlorolepidotus). All 411 wild and captive birds were negative for the presence of neutralizing antibody to PDV. These results indicate that wild sulphur-crested cockatoos in NSW are enzootically infected with avian polyomavirus and that the sampled populations are free of Pacheco's disease.

Heart failure in a macaw with atherosclerosis of the aorta and brachiocephalic arteries.

A female severe macaw (Ara severa) that was at least 11 years old was evaluated for sudden onset of exercise intolerance and dyspnea. Radiography revealed a large heart silhouette, an increase in prominence of the brachiocephalic arteries, and a diffuse increase in opacity of the lungs. Lateral nonselective angiography revealed dilatation of both chambers of the right side of the heart and incomplete emptying of the right atrium. Alterations in the shape and position of the left-side heart chambers and reduction in blood flow through the brachiocephalic arteries and aorta were identified. Despite treatment, the bird died suddenly 2.5 months after the first episode of dyspnea. At necropsy, severe atherosclerosis of the aorta and brachiocephalic arteries, dilatation of all heart chambers, pulmonary edema, and severe hepatic centrolobular atrophy and fibrosis were identified. Correlation between the angiography and necropsy findings suggested that angiography could be an important diagnostic tool for the detection of cardiovascular disease in birds.

Characterization of the avian polyomavirus-associated glomerulopathy of nestling parrots.

The glomerulopathy occurring in nestling nonbudgerigar parrots with avian polyomavirus (APV) disease was examined in 10 parrots. Glomerular lesions were characterized by the presence of dense, periodic acid-Schiff (PAS)-positive material that expanded the mesangium and that narrowed and at times occluded capillary lumina. PAS-staining was found to be more sensitive than hematoxylin and eosin in the detection of the lesions. Ultrastructurally, finely granular electron-dense material was found in massive intracapillary and mesangial condensates. Capillary endothelial cells exhibited changes consistent with cellular swelling. No evidence of chronic glomerular changes was observed. Immunofluorescent staining demonstrated that the PAS-positive, electron-dense condensates were complexes of IgG, avian polyomavirus antigen, and, in one bird, IgM. Viral DNA was detected in the serum of all six birds examined. Anti-APV antibodies were also present in all five serum samples examined. These findings suggested that the pathogenesis of this acute immune complex glomerulopathy and other APV-associated lesions depends on the presence of an appropriate ratio of circulating virus and anti-APV antibody.

Failure of maternally derived yolk IgG to reach detectable concentrations in the sera of nestling budgerigars (Melopsittacus undulatus).

Transfer of maternal immunoglobulin G (IgG) to the yolk and nestling was investigated in the budgerigar. Specific antibodies to avian polyomavirus and Newcastle disease virus could be detected in 82% of yolk extracts of eggs from seropositive hens. Using a double immunodiffusion assay with anti-chicken IgG antibodies, IgG could also be detected in yolk supernatants with virus neutralizing activity. In all assays, IgG concentrations in the yolk extracts were significantly less than those of the adult budgerigar serum. No antiviral activity was detected in nestling serum. Examination of nestling serum with the double immunodiffusion assay and an immuno-dot-blot technique specific for IgG showed that detectable concentrations of IgG are not present in nestling serum until after the yolk sac is fully absorbed. This observation, coupled with the absence of specific anti-viral antibody in nestlings of seropositive hens, indicated that none of the yolk sac antibody reached the nestling circulation.