Psittacine Birds Research Articles

Distribution of lesions in psittacine birds naturally infected with parrot bornavirus in Japan.

Mononuclear cell infiltration of the central nervous system and ganglioneuritis are characteristic histopathological findings of proventricular dilatation disease (PDD) caused by parrot bornavirus (PaBV) infection. The purpose of this study was to clarify the link between the degree of inflammatory lesions and the distribution of the virus antigen in naturally PaBV-infected parrots. Pathological examination was performed on 18 PaBV-infected birds identified by reverse transcriptase-PCR. Dilatation of the crop, proventriculus, and ventriculus was observed in all 18 (100%) birds, and dilation of the right ventricle of the heart was observed in 14/18 (78%) birds. Cases were classified based on the scores for the distribution and degree of histological lesions into neural type, with severe brain lesions, digestive type, with severe gastric lesions, or nervous/digestive type, with severe lesions in both the brain and ventriculus. The PaBV immunohistological score correlated with the inflammatory lesion scores. Ganglioneuritis, myocarditis, and myocardial degeneration were frequently observed in the heart. Interestingly, macroscopic and microscopic lesions and virus antigen were detected in the hearts of all three histological types. The present study showed that parrots naturally infected with PaBVs can be grouped into three types based on the lesion distribution, and heart failure is an important symptom in PaBV-infected parrots.

High prevalence and genetic heterogeneity of adenoviruses at a psittacine breeding facility.

A polymerase chain reaction (PCR) survey was performed at an amateur parrot breeding facility in Italy to investigate the presence and molecular characteristics of adenoviruses. Eighty psittacine birds, belonging to seven parrot species, were sampled by cloacal swabs; in addition, 15 livers were collected from specimens that were found dead. Seventy-two out of 95 samples collected were positive for adenoviruses, with a prevalence rate of 75.8%. All seven psittacine species tested positive for at least one genus of the family Adenoviridae; notably, adenoviral infection was found for the first time in the hooded parrot (Psephotellus dissimilis). Based on the sequences and phylogenetic analysis, 57 sequences were psittacine adenovirus 2, seven sequences were duck adenovirus 1 and two sequences were identified as psittacine adenovirus 5. The six remaining sequences showed low nucleotide and amino acid identity with the reference strains of accepted species or types, revealing the presence of novel adenoviruses belonging to the genera Aviadenovirus, Barthadenovirus and Siadenovirus. There were identical adenovirus sequences in both apparently healthy and dead birds suggesting that further investigation into the role and impact of these viruses on the health of psittacine birds is warranted.

Retrospective evaluation of voriconazole treatment in psittacines: 14 cases (2012-2023).

To retrospectively evaluate the clinical use of voriconazole in psittacine patients for the treatment of suspected respiratory fungal infections. 14 client-owned psittacine birds. Medical records were searched from 2012 to 2023 for voriconazole use in psittacines. Species, age, clinical signs, physical examination findings, CT reports, bloodwork results, treatment, and outcome were obtained from the records or client follow-up. African grey parrots were the most prevalent species (8/14). Dyspnea (9/14) and abnormal respiratory auscultation (11/14) were the most common examination abnormalities. An initial CT was performed in all cases, and pneumonia (10/14) and air sac disease (9/14) were the most common findings, with 8 cases having both pulmonary and air sac disease. Voriconazole doses ranged from 10 to 21 mg/kg (median, 16 mg/kg), with most cases prescribed as every-12-hour frequency (12/14). Three of 14 (21%) cases died or were euthanized within 24 days of diagnosis. One case was euthanized at 311 days, and 6 cases were lost to follow-up. Four of 14 (29%) cases lived > 12 months from diagnosis. Two of these cases cleared clinical infection after receiving voriconazole at 17 to 18 mg/kg (q 12 h). No adverse effects attributable to voriconazole were reported. Voriconazole can be safely used for the treatment of suspected fungal respiratory infection in psittacines. However, the prognosis for resolution is guarded, and prolonged treatment and repeated diagnostic imaging are necessary in many cases.

Prevalence, Anatomical Distribution, and Risk Factors of Adipocytic Tumors and Xanthomas in Psittaciformes: 1096 Cases (1998-2018).

Adipocytic tumors are mesenchymal tumors that are commonly reported in psittacine birds; however, large-scale studies evaluating their prevalence and associated risk factors are lacking. A retrospective study of adipocytic tumors in psittacine birds was performed by reviewing pathology submissions from the University of California, Davis-Drury Reavill Pathology Database, containing 26 013 submissions from psittacine birds (1998-2018). Age, sex, genus, anatomic distribution, and pathological diagnosis were collected for each case when available. The prevalence, risk factors, and association with other lipid-accumulation disorders were reported. A total of 450 cases of lipoma, 129 cases of myelolipoma, 35 cases of hemangiolipoma, 31 cases of liposarcoma, and 451 cases of xanthoma were identified. The prevalence of adipocytic tumors and xanthomas on necropsy was 1.3% (158/11 737, 95% confidence interval [CI]: 1.1-1.6). Adipocytic tumors were identified in 27 genera. Amazona (odds ratio [OR] = 1.93, 95% CI: 1.24-2.99, p = 0.004), Myiopsitta (OR = 2.3, 95% CI: 1.0-5.2, p = 0.041), Melopsittacus (OR = 3.4, 95% CI: 2.1-5.5, p < 0.001), and Agapornis (OR = 3.5, 95% CI: 2.0-6.1, p < 0.001) had significantly higher odds of developing adipocytic tumors compared with other genera, whereas Ara had significantly lower odds (OR = 0.5, 95% CI: 0.3-0.9, p = 0.030). Age was also a significant risk factor for many types of adipocytic tumors. There was no significant association between general adipocytic tumor formation and atherosclerosis or hepatic lipidosis. Xanthomas were associated with atherosclerosis (OR = 1.88, 95% CI: 1.01-3.51, p = 0.048), but not hepatic lipidosis (p = 0.503). On necropsy, the trunk and air sacs were the most common sites of xanthoma formation, whereas the trunk and liver were the most common sites of lipoma and myelolipoma formation, respectively.

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.

Surveillance of Parrot Bornavirus in Taiwan Captive Psittaciformes

Parrot bornavirus (PaBV) is an infectious disease linked with proventricular dilatation disease (PDD) with severe digestive and neurological symptoms affecting psittacine birds. Despite its detection in 2008, PaBV prevalence in Taiwan remains unexplored. Taiwan is one of the leading psittacine bird breeders; hence, understanding the distribution of PaBV aids preventive measures in controlling spread, early disease recognition, epidemiology, and transmission dynamics. Here, we aimed to detect the prevalence rate of PaBV and assess its genetic variation in Taiwan. Among 124 psittacine birds tested, fifty-seven were PaBV-positive, a prevalence rate of 45.97%. Most of the PaBV infections were adult psittacine birds, with five birds surviving the infection, resulting in a low survival rate (8.77%). A year of parrot bornavirus surveillance presented a seasonal pattern, with peak PaBV infection rates occurring in the spring season (68%) and the least in the summer season (25%), indicating the occurrence of PaBV infections linked to seasonal factors. Histopathology reveals severe meningoencephalitis in the cerebellum and dilated cardiomyopathy of the heart in psittacine birds who suffered from PDD. Three brain samples underwent X/P gene sequencing, revealing PaBV-2 and PaBV-4 viral genotypes through phylogenetic analyses. This underscores the necessity for ongoing PaBV surveillance and further investigation into its pathophysiology and transmission routes.

Avian Polyomavirus Among Psittacine Birds in Iran: Molecular Detection Rate and Associated Risk Factors.

Avian polyomavirus (APV) infection causes various health problems in psittacine species, including death. The present study was conducted to investigate the prevalence of APV among psittacine birds in Iran. We also aimed to evaluate the impact of age, sex, species, season, and origin of the birds on the prevalence of APV. This study investigated the presence of APV among 1050 individual birds from 7 psittacine species over a 1-year period in Iran, namely, green-cheeked parakeets (Pyrrhura molinae), rosy-faced lovebirds (Agapornis roseicollis), monk parakeets (Myiopsitta monachus), sun conures (Aratinga solstitialis), Senegal parrots (Poicephalus senegalus), cockatiels (Nymphicus hollandicus), and grey parrots (Psittacus erithacus). The overall prevalence of APV in all studied species was 25% (263/1050, 95% confidence interval [CI]: 22.5-27.8). Results of the study showed that age and the season of the year were 2 important determinant factors in the prevalence of APV in psittacine birds. Young psittacine birds <6 months old were 2.94 (95% CI: 1.19-7.27) times more likely to be infected with APV than birds >1 year old, and there was a significant interaction between season and species in the multivariate analysis. In the winter season, rosy-faced lovebirds and green-cheeked parakeets were 15.6 (95% CI: 4.20-57.95) and 4.76 (95% CI: 1.4-16.21) times more likely to be infected with APV than in other seasons, respectively. This is the first report on the detection rate of APV in psittacine birds in Iran.

Antimicrobial Sensitivity Profile in Psittacine Birds at an Avian Teaching Hospital: A Retrospective Study, 2015-2022.

Veterinary hospitals house patient populations with diverse infectious statuses, microbiota, and histories of prior antibiotic therapy. Choanal swabs are commonly used for assessing the upper respiratory tract of birds for bacterial disease, with the samples submitted for cytologic testing and/or culture and antimicrobial sensitivity testing. The aim of this retrospective study was to identify and quantify bacteria isolated from choanal swabs collected from psittacine patients at a veterinary teaching hospital in Mexico City, Mexico. Data regarding bacterial isolates from choanal swabs were obtained from the medical records of companion psittacines suspected of upper respiratory bacterial disease that presented between November 2015 and December 2022. A total of 47.8% (175 of 366) of the bacterial isolates were from specimens obtained from red-lored Amazons (Amazona autumnalis). Gram-negative bacteria predominated, with 27 different genera identified. Klebsiella, Staphylococcus, and Escherichia were the most frequently isolated genera. A total of 90.4% (331 of 366) of the isolates were resistant to at least 1 antibiotic tested in the sensitivity panel, and a single Klebsiella isolate was resistant to 13 different antibiotics. Gentamicin had a high percentage of efficacy (79.5%; 182 of 229) against the bacterial isolates, whereas isolates tested against sulfonamide-trimethoprim (46.7%, 98 of 210), streptomycin (43.8%; 88 of 201), and clindamycin (12.9%; 15 of 116) had susceptibilities <50%. This is the first study to report common bacterial isolates and their antimicrobial susceptibility patterns from choanal swab samples collected from companion psittacines suspected of upper respiratory disease in Mexico. Clinicians can use the information presented in this study as a guide for therapeutic decision-making when managing upper respiratory bacterial infections in companion psittacine patients.

Surgical Repair of Psittacine Femorotibial Luxation: A Case Series.

Luxation of the psittacine femorotibial joint most commonly occurs following trauma or as a development abnormality. Historically, this injury is considered to have a poor prognosis in birds; however, surgical management may result in acceptable and functional outcomes. This case series describes the surgical techniques, complications, and outcomes of 7 cases of femorotibial luxation in psittacine birds. Of the 7 cases, 6 were chronic injuries. Surgical repair methods included conjoined intramedullary pinning, transarticular pinning with an external skeletal fixator (ESF), a combination of extracapsular stabilization and ESF, ESF alone, and a combination of conjoined intramedullary pins with an ESF. An acceptable outcome was achieved in 75% (6/8) of luxated femorotibial joints managed with surgical methods. All cases were female birds of various species, suggesting a possible sex predisposition for stifle luxation.

Adenocarcinoma of the distal esophagus and esophageal-proventricular junction in a yellow-naped parrot.

A 57-y-old male yellow-naped parrot (Amazona auropalliata) was presented because of lethargy, inappetence, and weight loss. Hematology and serum biochemistry were unremarkable, and imaging revealed a mass in the distal esophagus at the coelomic inlet. The luminal diameter of the esophagus was reduced in this area, and passage of ingesta was limited. Following gavage feeding, the patient died and was submitted for autopsy. At postmortem examination, the noted mass effect was a thickening of the distal esophagus with adherent, coalescing, soft, pale-tan plaques on the mucosal surface. Additional gross findings included pale-tan, opaque feed material oozing from the dorsum of the lungs and covering the cranial air sacs. Histology of the esophagus, esophageal-proventricular junction, and proximal proventriculus revealed an unencapsulated, infiltrative, transmural neoplasm that extended from the mucosal surface deep into the muscularis, almost to the adventitia. The neoplasm was composed of cuboidal cells arranged in islands and tubules, consistent with an adenocarcinoma, a rarely reported entity in the esophagus of psittacine birds and to our knowledge not reported previously at the esophageal-proventricular junction.

Prevalence, genotypes, and infection risk factors of psittacine beak and feather disease virus and budgerigar fledgling disease virus in captive birds in Hong Kong

Psittacine beak and feather disease virus (PBFDV) and budgerigar fledgling disease virus (BFDV) are significant avian pathogens that threaten both captive and wild birds, particularly parrots, which are common hosts. This study involved sampling and testing of 516 captive birds from households, pet shops, and an animal clinic in Hong Kong for PBFDV and BFDV. The results showed that PBFDV and BFDV were present in 7.17% and 0.58% of the samples, respectively. These rates were lower than those reported in most parts of Asia. Notably, the infection rates of PBFDV in pet shops were significantly higher compared to other sources, while no BFDV-positive samples were found in pet shops. Most of the positive samples came from parrots, but PBFDV was also detected in two non-parrot species, including Swinhoe’s white-eyes (Zosterops simplex), which had not been reported previously. The ability of PBFDV to infect both psittacine and passerine birds is concerning, especially in densely populated urban areas such as Hong Kong, where captive flocks come into close contact with wildlife. Phylogenetic analysis of the Cap and Rep genes of PBFDV revealed that the strains found in Hong Kong were closely related to those in Europe and other parts of Asia, including mainland China, Thailand, Taiwan, and Saudi Arabia. These findings indicate the presence of both viruses among captive birds in Hong Kong. We recommend implementing regular surveillance for both viruses and adopting measures to prevent contact between captive and wild birds, thereby reducing the transmission of introduced diseases to native species.

Avian Polyomavirus Among Psittacine Birds in Iran: Molecular Detection Rate and Associated Risk Factors.

Avian polyomavirus (APV) infection causes various health problems in psittacine species, including death. The present study was conducted to investigate the prevalence of APV among psittacine birds in Iran. We also aimed to evaluate the impact of age, sex, species, season, and origin of the birds on the prevalence of APV. This study investigated the presence of APV among 1050 individual birds from 7 psittacine species over a 1-year period in Iran, namely, green-cheeked parakeets (Pyrrhura molinae), rosy-faced lovebirds (Agapornis roseicollis), monk parakeets (Myiopsitta monachus), sun conures (Aratinga solstitialis), Senegal parrots (Poicephalus senegalus), cockatiels (Nymphicus hollandicus), and grey parrots (Psittacus erithacus). The overall prevalence of APV in all studied species was 25% (263/1050, 95% confidence interval [CI]: 22.5-27.8). Results of the study showed that age and the season of the year were 2 important determinant factors in the prevalence of APV in psittacine birds. Young psittacine birds <6 months old were 2.94 (95% CI: 1.19-7.27) times more likely to be infected with APV than birds >1 year old, and there was a significant interaction between season and species in the multivariate analysis. In the winter season, rosy-faced lovebirds and green-cheeked parakeets were 15.6 (95% CI: 4.20-57.95) and 4.76 (95% CI: 1.4-16.21) times more likely to be infected with APV than in other seasons, respectively. This is the first report on the detection rate of APV in psittacine birds in Iran.

Surgical Repair of Psittacine Femorotibial Luxation: A Case Series.

Luxation of the psittacine femorotibial joint most commonly occurs following trauma or as a development abnormality. Historically, this injury is considered to have a poor prognosis in birds; however, surgical management may result in acceptable and functional outcomes. This case series describes the surgical techniques, complications, and outcomes of 7 cases of femorotibial luxation in psittacine birds. Of the 7 cases, 6 were chronic injuries. Surgical repair methods included conjoined intramedullary pinning, transarticular pinning with an external skeletal fixator (ESF), a combination of extracapsular stabilization and ESF, ESF alone, and a combination of conjoined intramedullary pins with an ESF. An acceptable outcome was achieved in 75% (6/8) of luxated femorotibial joints managed with surgical methods. All cases were female birds of various species, suggesting a possible sex predisposition for stifle luxation.

Antimicrobial Sensitivity Profile in Psittacine Birds at an Avian Teaching Hospital: A Retrospective Study, 2015-2022.

Veterinary hospitals house patient populations with diverse infectious statuses, microbiota, and histories of prior antibiotic therapy. Choanal swabs are commonly used for assessing the upper respiratory tract of birds for bacterial disease, with the samples submitted for cytologic testing and/or culture and antimicrobial sensitivity testing. The aim of this retrospective study was to identify and quantify bacteria isolated from choanal swabs collected from psittacine patients at a veterinary teaching hospital in Mexico City, Mexico. Data regarding bacterial isolates from choanal swabs were obtained from the medical records of companion psittacines suspected of upper respiratory bacterial disease that presented between November 2015 and December 2022. A total of 47.8% (175 of 366) of the bacterial isolates were from specimens obtained from red-lored Amazons (Amazona autumnalis). Gram-negative bacteria predominated, with 27 different genera identified. Klebsiella, Staphylococcus, and Escherichia were the most frequently isolated genera. A total of 90.4% (331 of 366) of the isolates were resistant to at least 1 antibiotic tested in the sensitivity panel, and a single Klebsiella isolate was resistant to 13 different antibiotics. Gentamicin had a high percentage of efficacy (79.5%; 182 of 229) against the bacterial isolates, whereas isolates tested against sulfonamide-trimethoprim (46.7%, 98 of 210), streptomycin (43.8%; 88 of 201), and clindamycin (12.9%; 15 of 116) had susceptibilities <50%. This is the first study to report common bacterial isolates and their antimicrobial susceptibility patterns from choanal swab samples collected from companion psittacines suspected of upper respiratory disease in Mexico. Clinicians can use the information presented in this study as a guide for therapeutic decision-making when managing upper respiratory bacterial infections in companion psittacine patients.

Dilated cardiomyopathy in a green-winged saltator (Saltator similis)

Cardiovascular diseases are rarely reported in birds. Among pet birds, they are most documented in psittacine birds. Dilated cardiomyopathy is a myocardial disease frequently found in poultry but with few reports in both pet and wild birds. An elderly male green-winged saltator (Saltator similis) died suddenly after presenting intermittent clinical signs of dyspnea, weakness, and vocalization changes. A general increase in cardiac size with a bulging apex was observed at necropsy. The heart exhibited an enlarged left ventricular space and flaccid musculature on the cut section. The liver was diffusely enlarged with rounded edges. No other gross lesions were observed. Samples were collected in 10% formalin and routinely processed. Histologically, bundles of myocardial fibers were irregularly arranged, with markedly elongated myofibrils and irregular cell contours. Additionally, multifocal areas of disruption were observed between the myofibrils. Diffuse hepatic congestion of sinusoids and portal veins was observed, and diffuse edema in the interstitium and para bronchi was present in the lungs. The clinical signs observed were nonspecific and can be found in several diseases of the cardiovascular and respiratory systems of birds. The gross and histological findings are compatible with what has been described for dilated cardiomyopathy in birds; however, left ventricular dilatation is uncommon in avian patients. Heart diseases in pet birds are still underdiagnosed, and reports of cardiomyopathies are limited to psittacine birds. To the authors’ knowledge, this is the first report of a dilated cardiomyopathy in a passerine bird.

Sequencing of pigeon circovirus and the first report of identification of beak and feather disease virus in clinical specimens of domestic pigeons.

An internationally recognized syndrome that leads to deaths among domestic and ornamental pigeons, particularly after racing, is young pigeon disease syndrome (YPDS). Pigeon circovirus (PiCV) is regarded as one of the potential factors contributing to the occurrence of YPDS. This survey was conducted to determine the prevalence of PiCV infection and molecularly characterize the PiCV in pigeons suspected of YPDS. Eighty fecal samples were collected from 80 diseased pigeons (exhibiting symptoms such as lethargy, weight loss, crop stasis, vomiting and diarrhea) from 20 lofts in different areas of Ahvaz, Iran. Also, 20 fecal samples were obtained from 20 clinically healthy pigeons. The nested broad spectrum polymerase chain reaction test was done to identify the circovirus, using primers targeting part of the replication-associated protein gene with 350 bp, and several positive samples were sequenced. This study showed that PiCV was detected in 86 out of the 100 samples (86.00%). Two types of circoviruses were determined in the samples. One type of the detected circoviruses was PiCV which based on phylogenetic analysis had high genetic similarity with A, B, G and H genotypes of PiCV. The other type of detected circoviruses was closely related to beak and feather disease virus (BFDV) which causes one of the most significant viral diseases in psittacine birds. This is the first report of BFDV identification in pigeons.

Pathological findings and their association with diseases of captive psittacine birds native to Mexico

The captivity and use of native psittacine birds is prohibited in Mexico. However, as these birds are among the groups most affected by illegal trafficking, they are commonly found as companion animals. Nevertheless, it is difficult to obtain information on their health. Therefore, a retrospective study was conducted of the clinical histories and necropsy reports of native psittacines that had been submitted to the Bird Disease Diagnostic and Research Laboratory of the Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, from 2006 to 2017. The lesions were classified according to type and anatomical location and the diseases were classified as infectious or non-infectious. During this period, 252 psittacines were submitted, the most frequent of which were the red-lored parrot (Amazona autumnalis), orange-fronted parakeet (Eupsittula canicularis) and scarlet macaw (Ara macao). The lesions were primarily located in the digestive and respiratory systems. By integrating the clinical histories and post-mortem findings, we concluded that nutritional disorders were the most frequent non-infectious diseases, systemic bacterial infections were the most frequent infectious conditions, the primary parasite was Sarcocystis spp and the most frequent neoplasm was multicentric lymphoma.

Species and seasonality can affect recent trends in beak and feather disease virus prevalence in captive psittacine birds

Beak and feather disease virus (BFDV) is globally distributed in psittacine birds. BFDV is considered a key threat to biodiversity because it has the ability to transmit and shift between host species. Data from captive psittacine birds can help to identify potential risk factors for viral transmission management. Generalized Linear Models (GLM) were used to examine the association of sample type, species, and season on the prevalence of BFDV in captive exotic birds in Thailand.In this study, the overall prevalence of BFDV was 8.2 %, with 346 of 4243 birds being positive. The prevalence in feather samples (12.1 %) and pooled (dried blood and feather) samples (15.4 %) was higher than that in the dried blood samples (4.8 %). A GLM test revealed that the sample type, species, and season were significant factors influencing the prevalence of BFDV. Based on the model, two species (blue-eyed cockatoo; Cacatua ophthalmica, and ring-necked parakeet; Psittacula krameri) were associated with higher BFDV prevalence. By studying the seasonal BFDV prevalence, we can gather important insights into the environmental factors that contribute to its spread. The higher prevalence observed during the wet season suggest a possible affect between BFDV prevalence and environmental factors such as heavy rainfall and humidity. In conclusion, our analysis of the trends in BFDV prevalence offers valuable insights into the prevalence or distribution of BFDV in the studied population. By monitoring BFDV prevalence, identifying high-risk species, and understanding seasonal patterns, we can develop targeted management approaches to control the spread of the virus. This information is crucial for mitigating the impact of BFDV on aviculture.

Detection of a Novel Alphaherpesvirus and Avihepadnavirus in a Plantar Papilloma from a Rainbow Lorikeet (Trichoglosis moluccanus).

Cutaneous plantar papillomas are a relatively common lesion of wild psittacine birds in Australia. Next-generation sequencing technology was used to investigate the potential aetiologic agent(s) for a plantar cutaneous papilloma in a wild rainbow lorikeet (Trichoglosis moluccanus). In the DNA from this lesion, two novel viral sequences were detected. The first was the partial sequence of a herpesvirus with the proposed name, psittacid alphaherpesvirus 6, from the Mardivirus genus of the family alphaherpesviruses. This represents the first mardivirus to be detected in a psittacine bird, the first mardivirus to be detected in a wild bird in Australia, and the second mardivirus to be found in a biopsy of an avian cutaneous papilloma. The second virus sequence was a complete sequence of a hepadnavirus, proposed as parrot hepatitis B genotype H (PHBV-H). PHBV-H is the first hepadnavirus to be detected in a wild psittacine bird in Australia. Whether other similar viruses are circulating in wild birds in Australia and whether either of these viruses play a role in the development of the plantar papilloma will require testing of biopsies from similar lesions and normal skin from other wild psittacine birds.

Radiographic Measurements of Internal Organs in Rhode Island Red Hybrid Hens (Gallus gallus domesticus) and Their Evolution During Egg Formation.

Backyard poultry hens are becoming very popular as pets, and thus the demand for treating the individual chicken is increasing. Few basic diagnostic techniques commonly used in small animal practice have been evaluated in this species. At the moment, there is no study in backyard hens describing radiographic measurements of internal organs contrary to psittacine birds or birds of prey. Moreover, the effect of egg laying on these measurements has not been studied in avian species even though it could affect radiographic measurements depending on the stage of egg formation. This is of particular concern in laying hens since they are able to lay on a daily basis. Thirteen adult hens and 3 juvenile Rhode Island red hybrid hens (Gallus gallus domesticus) were used to evaluate which organs can be reliably measured and to provide preliminary reference values for clinically healthy chickens. Additionally, whole body radiographs were collected every 2 hours over 24 hours in 5 adult hens to study the evolution of these measurements throughout egg formation. Organs that could be clearly delimitated on radiographs were measured, and the only organs that could be reliably measured were the heart and liver silhouettes. These measurements were significantly higher in adult compared to juvenile hens (P = 0.024). Among the different organ ratios, heart width: total liver width ratio was the only significantly different measurement and was higher in juvenile hens (P = 0.024). Hepatic silhouette measurements and ratios were found to increase over time (P < 0.02) but did not follow the progress of egg mineralization. Eggshell thickness was found to be a promising parameter to evaluate the stage of egg formation, and thus should be taken into account when trying to establish reference intervals for radiographic measurements of internal organs in laying hens.