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PubMed1998

Rhizomucor pusillus mucormycosis combined with chlamydiosis in an African grey parrot (Psittacus erithacus erithacus).

This paper describes a case of mucormycosis combined with chlamydiosis in an African grey parrot (Psittacus erithacus erithacus). The clinical signs included diarrhoea, an unsteady gait and a twisted neck. Smears of the spleen, liver and contents of the cloaca stained strongly positive for Chlamydia species. Histologically, hyphae typical of Zygomycetes were observed invading through the walls of blood vessels of the spleen. Rhizomucor pusillus was isolated as a pure culture from the intestines, lungs and liver.

Animals↗

PubMed2006

Multisite integumentary squamous cell carcinoma in an African grey parrot (Psittacus erithacus erithacus).

A 22-year-old male African grey parrot (Psittacus erithacus erithacus) had had episodes of chronic feather picking and self-mutilation for 10 years; it had a 5 cm diameter right axillary wound and a 2 cm left dorsal patagial wound. Initial treatment with azithromycin and wound management was unsuccessful. Biopsies of both masses indicated squamous cell carcinoma. The left patagial tumour was removed completely by electrocautery. Cisplatin was administered weekly into multiple sites on the right axillary tumour and it initially appeared to regress; however, the bird's condition deteriorated after a month of treatment, and it was euthanased. The tumour was confirmed postmortem to be squamous cell carcinoma, which had invaded local tissues. The aetiology of the carcinoma may have been secondary to chronic focal trauma.

Animals↗

PubMed1980

In vitro studies of sodium transport across the lower intestine of a desert parrot.

The lower intestine (coprodeum and colon) of the Australian parrot, the galah, was mounted in Ussing chambers. Short-circuit current (SCC), electrical potential difference (PD), and unidirectional fluxes of Na and Cl were measured in birds that were fed mixed seeds or were NaCl loaded. The net Na transport of both coprodeum and colon was nearly equal to the SCC, and the flux ratio for Cl was unity. In birds which received mixed seeds, average coprodeal Na transport was 7.8 mu eq . cm-2 . h-1, and PD was 19 mV. The Km for Na was 5.7 meq/l. In colon, Na transport was reduced by 67% and PD by 70%. The ratio between unidirectional Na and Cl fluxes in the serosa-mucosa direction was 0.7. Salt loading suppressed coprodeal, but increased colonic Na transport. The coprodeal and colonic SCC and NA transport of birds receiving mixed seeds were inhibited by amiloride on the mucosal side. Colonic SCC of NaCl-loaded birds was only slightly reduced by amiloride (by 17%), but stimulated by amino acids (by 18%).

Amiloride↗

PubMed2004

Interspecific allometry of the brain and brain regions in parrots (psittaciformes): comparisons with other birds and primates.

Despite significant progress in understanding the evolution of the mammalian brain, relatively little is known of the patterns of evolutionary change in the avian brain. In particular, statements regarding which avian taxa have relatively larger brains and brain regions are based on small sample sizes and statistical analyses are generally lacking. We tested whether psittaciforms (parrots, cockatoos and lorikeets) have larger brains and forebrains than other birds using both conventional and phylogenetically based methods. In addition, we compared the psittaciforms to primates to determine if cognitive similarities between the two groups were reflected by similarities in brain and telencephalic volumes. Overall, psittaciforms have relatively larger brains and telencephala than most other non-passerine orders. No significant difference in relative brain or telencephalic volume was detected between psittaciforms and passerines. Comparisons of other brain region sizes between psittaciforms and other birds, however, exhibited conflicting results depending upon whether body mass or a brain volume remainder (total brain volume - brain region volume) was used as a scaling variable. When compared to primates, psittaciforms possessed similar relative brain and telencephalic volumes. The only exception to this was that in some analyses psittaciforms had significantly larger telencephala than primates of similar brain volume. The results therefore provide empirical evidence for previous claims that psittaciforms possess relatively large brains and telencephala. Despite the variability in the results, it is clear that psittaciforms tend to possess large brains and telencephala relative to non-passerines and are similar to primates in this regard. Although it could be suggested that this reflects the advanced cognitive abilities of psittaciforms, similar studies performed in corvids and other avian taxa will be required before this claim can be made with any certainty.

Animals↗

PubMed1990

Origins of descending spinal pathways in prehensile birds: do parrots have a homologue to the corticospinal tract of mammals?

In mammals, the supraspinal descending projections that influence distal limb muscles are the rubrospinal and corticospinal tracts. The former, which is found in other vertebrates, shows greater somatotopy in mammals that are 'dextrous' (e.g. monkeys) than those that are not (e.g. opossums). Similarly, the corticospinal tract, which is found only in mammals, has more extensive connections (i.e. direct corticomotoneural) in mammals that are dextrous than in mammals that are not. Descending spinal pathways have been described in 'non-dextrous' avian species (chickens, ducks, geese and pigeons), and the purpose of this study was to determine if there are any differences in the origins of descending projections to the spinal cord in 'dextrous' or prehensile parrots (sulphur-crested cockatoo, Cacatua galerita, and eastern rosella, Platycerus eximius). True Blue or wheat germ agglutinin-horseradish peroxidase was injected into the lumbar or cervical spinal cord. The distribution of retrogradely labelled cells was similar to that previously reported for non-prehensile birds. We found no evidence of any direct spinal projections from the telencephalon (including any pathway homologous to the corticospinal tract of mammals), nor any specialized anatomical organization of the descending pathways that could account for the pedal dexterity of these species.

Animals↗

PubMed1988

Presumptive relict reproductive behavior in small parrots.

Recent studies of experimentally elicited egg-care behaviors in three species of small, hole-nesting parrots, and of their evolutionary implications are reviewed. A suite of primarily nonthermal egg-care responses are adaptive for nesting in shallow terrestrial scrapes, rather than in cavities. These responses appear to be relics from times before hole-nesting began; as such, they may provide 'windows' into certain nonthermal aspects of terrestrial-nesting practices during ancestral stages. A suite of primarily thermal egg-care behaviors, elicited when nests are exposed to light and view, progress from mere initial curiosity, inspection, and manipulation of fostered eggs by nonbreeding parents, to more extensive manipulation and episodic concealment of a pair's own eggs by crouching over them, to crouching lengthily over eggs with some incubation but nighttime abandonment, to continuous 24-hour incubation. This progression may retrace certain aspects of major ancestral stages of thermal egg care. Stages of primary oocytes and follicles during ovarian development, and of maturing follicles during breeding cycles of some species, may retrace the phylogenetic progression of sizes of ancestral clutches and ripe follicles. These phenomena and the retention of many of the experimentally elicited egg-care responses are attributed largely to the highly conservative evolution of the central nervous system.

Animals↗

PubMed1992

Molecular cloning and partial characterization of a parrot papillomavirus.

The genome of a papillomavirus isolated from a cutaneous lesion on the head of an African grey parrot (Psittacus erithacus timneh) was cloned into pBR322, and a restriction map was prepared. Several short portions of the DNA were sequenced allowing the genome to be aligned with HPV-la. In Southern blot hybridizations, under conditions of low and medium stringency (Tm-40 and -33 degrees), but not at a higher stringency, this viral DNA annealed weakly with only 1 of 17 mammalian papillomavirus genomes tested. Furthermore, PePV DNA hybridized with the DNA from the European chaffinch only at low stringency, indicating that it represents a unique avian papillomavirus.

Animals↗

PubMed2001

Hepatic hyaline globules in an Eclectus parrot (Eclectus roratus).

Hepatic hyaline globules, similar to those reported in some human livers, were observed in liver tissue from an Eclectus parrot (Eclectus roratus). The cytoplasmic inclusions were periodic acid-Schiff positive and diastase resistant and failed to stain by acid-fast or Congo red techniques. Ultrastructurally, the hepatic globules were composed of granular amorphous material with small peripheral striations that extended into the cytoplasm.

Animals↗

PubMed2002

Avian papillomaviruses: the parrot Psittacus erithacus papillomavirus (PePV) genome has a unique organization of the early protein region and is phylogenetically related to the chaffinch papillomavirus.

BACKGROUND: An avian papillomavirus genome has been cloned from a cutaneous exophytic papilloma from an African grey parrot (Psittacus erithacus). The nucleotide sequence, genome organization, and phylogenetic position of the Psittacus erithacus papillomavirus (PePV) were determined. This PePV sequence represents the first complete avian papillomavirus genome defined. RESULTS: The PePV genome (7304 basepairs) differs from other papillomaviruses, in that it has a unique organization of the early protein region lacking classical E6 and E7 open reading frames. Phylogenetic comparison of the PePV sequence with partial E1 and L1 sequences of the chaffinch (Fringilla coelebs) papillomavirus (FPV) reveals that these two avian papillomaviruses form a monophyletic cluster with a common branch that originates near the unresolved center of the papillomavirus evolutionary tree. CONCLUSIONS: The PePV genome has a unique layout of the early protein region which represents a novel prototypic genomic organization for avian papillomaviruses. The close relationship between PePV and FPV, and between their Psittaciformes and Passeriformes hosts, supports the hypothesis that papillomaviruses have co-evolved and speciated together with their host species throughout evolution.

5' Untranslated Regions↗

PubMed2002

Direct observation of syringeal muscle function in songbirds and a parrot.

The role of syringeal muscles in controlling the aperture of the avian vocal organ, the syrinx, was evaluated directly for the first time by observing and filming through an endoscope while electrically stimulating different muscle groups of anaesthetised birds. In songbirds (brown thrashers, Toxostoma rufum, and cardinals, Cardinalis cardinalis), direct observations of the biomechanical effects of contraction largely confirm the functions of the intrinsic syringeal muscles proposed from indirect studies. Contraction of the dorsal muscles, m. syringealis dorsalis (dS) and m. tracheobronchialis dorsalis, constricts the syringeal lumen and thus reduces airflow by adducting connective tissue masses, the medial (ML) and lateral (LL) labia. Activity of the medial portion of the dS appears to affect the position of the ML and, consequently, plays a previously undescribed role in aperture control. Under the experimental conditions used in this study, full constriction of the syringeal lumen could not be achieved by stimulating adductor muscles. Full closure may require simultaneous activation of extrinsic syringeal muscles or the supine positioning of the bird may have exerted excessive tension on the syrinx. Contraction of m. tracheobronchialis ventralis enlarges the syringeal lumen and thus increases airflow by abducting the LL but does not affect the ML. The largest syringeal muscle, m. syringealis ventralis, plays a minor role, if any, in direct aperture control and thus in gating airflow. In parrots (cockatiels, Nymphicus hollandicus), direct observations show that even during quiet respiration the lateral tympaniform membranes (LTMs) are partially adducted into the tracheal lumen to form a narrow slot. Contraction of the superficial intrinsic muscle, m. syringealis superficialis, adducts the LTMs further into the tracheal lumen but does not close the syringeal aperture fully. The intrinsic deep muscle, m. syringealis profundus, abducts the LTMs through cranio-lateral movement of a paired, protruding half-ring. The weakly developed extrinsic m. sternotrachealis seems to increase tension in the ipsilateral LTM but does not move it in or out of the syringeal lumen.

Animals↗

PubMedDate not supplied

Hypercalcemia in two Amazon parrots with malignant lymphoma.

Malignant lymphoma is a common malignancy in birds. Paraneoplastic syndromes, which are commonly observed in domestic animals, have not been reported in association with lymphoma in birds. Hypercalcemia and hyperglobulinemia were found on plasma chemistry in two Amazon parrots, which were presented with aspecific symptoms. In both cases radiography and ultrasound demonstrated signs of hepatomegaly, which proved to be due to malignant lymphoma on postmortem examination. The hypercalcemia was found to be most consistent with a paraneoplastic effect of the malignant lymphoma in these birds. The exact origin of the hyperglobulinemia remains unclear.

Animals↗

PubMed2003

Acetylcholinesterase concentrations in heparinized blood of Hispaniolan Amazon parrots (Amazona ventralis).

Organophosphate and carbamate pesticides inhibit acetylcholinesterase (AChE) at nerve synapses. Blood samples from 22 Hispaniolan Amazon parrots (Amazona ventralis) were assayed for cholinesterase levels by two different techniques. Using the modified Michel method, the whole-blood cholinesterase activity levels ranged from 0.082 to 0.616 deltapH/hr with a mean value of 0.35 deltapH/hr. A reference range (0.08-0.62 deltapH/hr) for cholinesterase was established in birds. The modified Ellman spectrophotometric method was used to measure AChE activity by adding acetylthiocholine or pseudocholinesterase (plasma cholinesterase) activity by adding butyrylthiocholine. The reference range of the AChE activity using the modified Ellman spectrophotometric method was 0-1.12 micromol/ml/min with a mean of 0.48 micromol/ml/min, and for pseudocholinesterase the range was 0.09-0.98 micromol/ml/min with a mean of 0.53 micromol/ml/min.

Acetylcholine↗

PubMed2004

An outbreak of chlamydiosis in captive blue-fronted Amazon parrots (Amazona aestiva) in Brazil.

Fifty-eight blue-fronted Amazon parrot (Amazona aestiva) nestlings, recovered from the illegal trade, became ill at a wildlife rehabilitation center in São Paulo State, Brazil. Clinical signs observed were nonspecific, and the mortality rate was 96.5% despite initial treatment with norfloxacin. Postmortem examinations were performed on 10 birds. Liver and spleen smears showed structures suggestive of Chlamydophila psittaci in four cases. Diagnosis was confirmed by seminested polymerase chain reaction on tissue samples. Other birds from the same location showed no clinical signs of the disease, although high complement fixation titers to C. psittaci were found in 10 adult psittacines. All birds in the facility were treated with doxycycline. The two surviving nestlings did not recover after two doxycycline treatments and were euthanatized. The high mortality rate observed in this outbreak was attributed to poor conditions of husbandry and delays in the diagnosis and treatment of the disease. After diagnosis, improved control measures for chlamydiosis were instituted.

Animal Husbandry↗

PubMed2000

Ureterotomy for removal of two ureteroliths in a parrot.

A 21-year-old male double-yellowheaded Amazon parrot was referred because of possible urolithiasis. The bird had strained to void since it was young, and recently, signs of depression and inappetence had appeared. Radiography revealed 2 mineralized opacities in the left caudal portion of the celomic cavity. A left lateral celiotomy revealed that the left ureter was dilated and contained a calculus, which was later determined to be composed of monosodium uric acid crystals and proteinaceous material. The second mineralized mass could not be located at that time, but was detected in the caudal aspect of the celomic cavity after surgery by use of radiography. Manual attempts to maneuver the uterolith from the ureter through the cloaca were unsuccessful. Five days after the initial surgery, the uterolith was removed by cloacotomy and ventral midline laparotomy. Excretory urography performed 10 and 31 days after surgery revealed that the left ureter was homogeneously opacified and gradually decreased to 3 to 6 mm in diameter. The bird remained healthy and seemed to strain less severely during voiding. Nonspecific signs associated with ureteroliths may result in delay in diagnosis. Surgical removal of ureteroliths may be an effective treatment for this uncommon condition, but it is complicated by certain anatomic features of birds and may result in ureteral stricture.

Animals↗

PubMedDate not supplied

Rosella parrot exposure as a cause of bird fancier's lung.

A case of a 30-year-old man who presented with a 2-month history of progressively worsening dyspnoea, cough, and reduced exercise tolerance is discussed. A chest x-ray and computerized tomography of the chest suggested interstitial lung disease, which was confirmed on histology of an open lung biopsy. Careful questioning revealed that the patient had sustained close exposure to a rosella parrot acquired as a pet 9 months prior to presentation, which led to the diagnosis of bird fancier's lung. The case, investigations, and outcome are presented. This is followed by a discussion on extrinsic allergic alveolitis with particular emphasis on the importance of a complete social and environmental history in patients presenting with similar respiratory symptoms.

Adult↗

PubMed2005

Small intestinal foreign body in an adult Eclectus parrot (Eclectus roratus).

A 14-month-old female Eclectus parrot (Eclectus roratus) was presented with a 4-week history of bloody diarrhea and depression. No additional information could be gained from physical examination. Only selected diagnostic tests (faecal examination, haematocrit, aspartate aminotransferase, and uric acid) could be performed due to financial constraints, but all where within reference range. Unspecific antibiotic treatment was started and the bird responded well initially, but had to be readmitted 2.5 weeks after initial presentation. Four weeks after initial presentation the owner finally consented to taking whole body radiographs and a diagnosis of an intestinal foreign body could be made. The foreign body was surgically removed 2 days later. The bird recovered uneventfully after surgery and was still in good health 1 year after surgery. This article emphasises the importance of diagnostic imaging in the avian patient. A brief review of avian gastrointestinal foreign bodies is given (concentrating on the psittacine patient) and the importance of distinguishing metallic from non-metallic gastrointestinal foreign bodies are discussed.

Animals↗

PubMed1981

Characterization of a Newcastle disease virus isolated from a parrot (Psittacus erythracus) in Nigeria.

The characteristics of a Newcastle disease virus isolated from a parrot (Psittacus erythracus) in Nigeria were examined using standard laboratory tests. Minimum lethal dose in embryos was 10(-10), mean death time 44.8 h. The intracerebral and intravenous pathologic indices were 1.65 and 2.42, respectively. The virus was resistant at pH 3 and pH 7.2 and the hemagglutinin was thermostable at 56 C for 120 min. Of 10 mammalian species of erythrocytes examined, those of equine and rat were not agglutinated. The isolate was typed as a velogenic viscerotropic Newcastle disease virus.

Animals↗

PubMed1999

Surgical management of bifid sternum in two African grey parrots.

Transposition of the pectoral muscles for treatment of caudal bifid (cleft) sternum in 2 unrelated African Grey Parrots is described. The birds did not have clinical signs of ventilatory compromise prior to surgery; however, both had cutaneous ulcers over the defects. The pectoral muscles provided a thick pad over the heart, minimizing the risk of trauma to the heart.

Animals↗