Psittacine Species Research Articles

Techniques for Drug Delivery in Psittacine Birds

Psittacine birds are challenging to medicate, because they can deliver a painful bite and can learn to resist drug administration. Some drug delivery systems require restraint or sedation for placement, which may not be tolerated by critically ill birds. In this article, drug-delivery strategies will be discussed regarding psittacine species, including the benefits and risks of each method as well as practical guidance based on the experience of this and other authors.

Isolation of a coronavirus from a green-cheeked Amazon parrot (Amazon viridigenalis Cassin)

A virus (AV71/99) was isolated from a green-cheeked Amazon parrot by propagation and passage in both primary embryo liver cells derived from blue and yellow macaw (Ara ararauna) embryos and chicken embryo liver cells. Electron microscopic examination of cytopathic agents derived from both types of cell cultures suggested that it was a coronavirus. This was confirmed using a pan-coronavirus reverse transcriptase polymerase chain reaction that amplified part of gene 1 that encodes the RNA-dependent RNA polymerase. The deduced sequence of 66 amino acids had 66 to 74% amino acid identity with the corresponding sequence of coronaviruses in groups 1, 2 and 3. Several other oligonucleotide primer pairs that give PCR products corresponding to genes 3, 5, N and the 3′-untranslated region of infectious bronchitis virus, turkey coronavirus and pheasant coronavirus (all in group 3) failed to do so with RNA from the parrot coronavirus. This is the first demonstration of a coronavirus in a psittacine species. Isolement d'un coronavirus d'un perroquet amazone à joues vertes (Amazon viridigenalis Cassin) Un virus (AV71/99) a été isolé d'un perroquet amazone à joues vertes sur des cultures primaires d'hépatocytes d'embryon d'ara bleu (Ara ararauna) et d'hépatocytes d'embryon de poulet, en réalisant des passages. L'examen en microscopie électronique des agents cytopathogènes dérivés des deux types de culture cellulaire a suggéré la présence d'un coronavirus. Ceci a été confirmé en utilisant les réactions de transcription inverse et d'amplification en chaîne par polymérase qui ont amplifié une partie du gène 1 qui code l'ARN polymérase ARN dépendante. La séquence déduite de 66 acides aminés présentait 66 à 74% d'identité en acides aminés avec la séquence correspondante des coronavirus des groupes 1, 2, et 3. Plusieurs autres paires d'amorce oligonucléotidique qui donnent des produits PCR correspondant aux gènes 3, 5, N et à la région 3' non traduite du virus de la bronchite infectieuse, du coronavirus de la dinde et du coronavirus du faisan (tous du groupe 3) n'ont pu le faire avec l'ARN du coronavirus du perroquet. C'est la première mise en évidence d'un coronavirus chez les psittacidés. Isolierung eines Coronavirus aus einer Grünwangen-Amazone (Amazona viridigenalis Cassin) Aus einer Grünwangen-Amazone (Amazon viridigenalis Cassin) wurde durch Anzüchtung und Passagierung in primären Embryoleberzellen von blauen und gelben Aras (Ara ararauna) sowie in Hühnerembryoleberzellen ein Virus isoliert (AV71/99). Die elektronenmikroskopische Untersuchung der zytopathogenen Agens aus beiden Zellkulturtypen ließ vermuten, dass es sich um ein Coronavirus handelte. Dieses wurde mittels einer für alle Coronaviren spezifischen Reverse Transkriptase- Polymerasekettenreaktion, die Teile des für die RNS-abhängige RNS-Polymerase kodierende Gen 1 amplifizierte. Die abgeleitete Sequenz aus 66 Aminosäuren wies eine 66–74%ige Aminosäurenübereinstimmung mit den entsprechenden Sequenzen der Coronaviren der Gruppen 1, 2 und 3 auf. Mehrere andere Oligonukleotidprimerpaare, die den Genen 3, 5, N und der nicht translatierten 3‘-Region des infektiösen Bronchitisvirus, des Putencoronavirus und des Fasanencoronavirus (alle in Gruppe 3) entsprechende PCR-Produkte amplifizieren, gelang dies nicht mit der RNS aus dem Papageiencoronavirus. Dies ist die Erstbeschreibung eines Coronavirus in einer Psittazidenspezies. Aislamiento de un coronavirus de un loro Amapola (Amazon viridigenalis Cassin) Se aisló un virus (AV71/99) de un loro Amapola mediante propagación y pases en células primarias de hígado de embrión derivadas de embriones de guacamayo azul y amarillo (Ara ararauna) y en células hepáticas de embrión de pollo. Los estudios en microscopio electrónico de los agentes citopáticos procedentes de ambos tipos de cultivos celulares sugirieron que se trataba de un coronavirus. Esto se confirmó mediante una transcriptasa reversa-reacción en cadena de la polimerasa de pan-coronavirus que amplificaba parte del gen 1 que codifica la RNA polimerasa-RNA dependiente. La secuencia deducida de 66 aminoácidos tenía entre el 66 al 74% de similitud aminoacídica con la correspondiente secuencia de los grupos 1, 2 y 3 de Coronavirus. Otros pares de cebadores oligonucleotídicos, que producen productos de PCR correspondientes a los genes 3, 5, N y a la región no codificantes 3’ del virus de la bronquitis infecciosa, del coronavirus del pavo y del coronavirus del faisán (todos ellos en el grupo 3), no amplificaron en el caso del coronavirus del loro. Esta es la primera descripción de un coronavirus en especies de psitácidas.

Sexual Dichromatism in the Blue-fronted Amazon Parrot (Amazona aestiva) Revealed by Multiple-angle Spectrometry

Seventy-five percent of psittacine species, including the blue-fronted Amazon parrot (Amazona aestiva), are classified as sexually monomorphic. However, this classification is based on the inability of the trichromatic human eye to perceive light in the near-ultraviolet spectrum. Spec- trometry is a technique that enables humans to recognize the increased range of color perceived by the tetrachromatic avian eye. By using this technique, researchers have reclassified many avian species as sexually dimorphic. In this exploratory study, several body regions of 30 blue-fronted Amazon parrots (males and females) were investigated by multiple-angle spectrometry. A model was developed that enabled gender prediction with 100% accuracy based on plumage color char- acteristics. However, the areas that were most promising in our model (forehead and wing tip) need to be confirmed independently to exclude the possibility of type I error attributed to multiple testing.

Beak and feather disease virus haemagglutinating activity using erythrocytes from African Grey parrots and Brown-headed parrots : research communication

Psittacine beak and feather disease (PBFD) is a common viral disease of wild and captive psittacine birds characterized by symmetric feather loss and beak deformities. The causative agent, beak and feather disease virus (BFDV), is a small, circular single-stranded DNA virus that belongs to the genus Circovirus. BFDV can be detected by PCR or the use of haemagglutination (HA) and haemagglutination inhibition (HI) assays that detect antigen and antibodies respectively. Erythrocytes from a limited number of psittacine species of Australian origin can be used in these tests. In South Africa, the high cost of these birds makes them difficult to obtain for experimental purposes. Investigation into the use of erythrocytes from African Grey parrots and Brown-headed parrots yielded positive results showing the haemagglutinating activity of their erythrocytes with purified BFDV obtained from confirmed clinical cases of the disease. The HA activity was further confirmed by the demonstration of HI using BFDV antiserum from three different African Grey parrots previously exposed to the virus and not showing clinical signs of the disease.

Assessment of Plasma Concentrations and Effects of Injectable Doxycycline in Three Psittacine Species

Abstract The disposition and effects of 2 formulations of injectable doxycycline administered at 100 mg/kg were investigated to determine if plasma concentrations considered adequate for treating avian chlamydiosis (1 μg/ml) could be safely maintained in 3 species of psittacine birds. Five orange-winged Amazon parrots (Amazona amazonica) that received a commercial doxycycline hyclate formulation (20 mg/ml) intramuscularly achieved maximum plasma doxycycline concentrations of 9.33 ± 0.82 μg/ml and maintained concentrations >1 μg/ml for 5 days. In a second trial, 8 orange-winged Amazon parrots and 8 Goffin's cockatoos (Cacatua goffini) received micronized pharmacist-compounded doxycycline (75 mg/ml IM). In orange-winged Amazon parrots, maximum plasma doxycycline concentration was 2.54 ± 0.38 μg/ml, and concentrations of approximately 0.5 μg/ml were sustained from 24–168 hours. In Goffin's cockatoos, maximum plasma doxycycline concentration was 3.49 ± 0.18 μg/ml, and concentrations >1 μg/ml were maintained f...

Ingluvial Squamous Cell Carcinoma in a Geriatric Cockatiel (Nymphicus hollandicus)

A 20-year-old male cockatiel (Nymphicus hollandicus) exhibiting dysphagia, regurgitation, and lethargy was diagnosed with invasive squamous cell carcinoma involving the crop. The neoplastic mass was closely associated with the right vagal nerve and was obstructing 80% of the crop lumen. Dysphagia appeared to be linked to nerve dysfunction resulting in ileus of the upper digestive tract. This is the first published report of squamous cell carcinoma in the crop of a psittacine species resulting in nerve dysfunction and possible vagal indigestion.

Determination of Indirect Blood Pressure in the Companion Bird

Abstract The information gathered through arterial blood pressure measurement must be correctly interpreted for appropriate decisions to be made. Systolic blood pressure is the pressure exerted against the blood vessel wall during systole. Although direct arterial pressure measurement is ideal, it is not commonly used because of the need for specific technical skill, invasive nature of the procedure, and cost of equipment. All indirect blood pressure measurement techniques are based on detection of blood flow beneath an inflated cuff. Systolic blood pressure determination via ultrasonic Doppler flow detection (Doppler) has been found to correlate well with direct blood pressure measurements in ducks ( Anas platyrhynchos). Clinical techniques and applications for Doppler blood pressure monitoring will be discussed. Treatment of hypotension involves monitoring blood pressure, removal of the underlying cause, and volume support for hypovolemia. Hypertension has not yet been defined in the psittacine species. The routine use of blood pressure monitoring in the avian species can provide the clinician with a better knowledge base about intravascular volume status to avoid or minimize long-term complications of hypertension.

Horner's Syndrome in a Red-bellied Parrot (Poicephalus rufiventris)

Abstract Horner's syndrome was diagnosed in a 3-year-old female red-bellied parrot (Poicephalus rufiventris). The cause of Horner's syndrome in this bird was thought to be trauma to the base of the neck. Clinical signs included unilateral ptosis and changes in the position and behavior of feathers on the affected side of the head and neck. The ptosis was markedly ameliorated after the sympathomimetic agent phenylephrine was applied locally, confirming the diagnosis. Involvement of feather follicles in Horner's syndrome has not been reported previously but is consistent with the exclusively adrenergic innervation of smooth muscles controlling feather movement. This is the second report of Horner's syndrome in a bird and the first in a psittacine species. The paucity of cases in birds is surprising, as head and neck trauma are common. Horner's syndrome should be considered as a differential diagnosis for ptosis in an avian species.

Attempted Semen Collection Using the Massage Technique and Semen Analysis in Various Psittacine Species

An established massage technique for semen collection in budgerigars, cockatiels, and monk parakeets was applied to 40 different birds of 26 different psittacine species in a period of 4 weeks. Semen collection was successful in 8 individual birds (Aratinga species, Tanygnathus species, Guarouba guarouba, and Pionus chalcopterus). Large parrot species (Ara ambigua, Cacatua leadbeateri, Amazona species, and Eclectus species) were difficult to handle and did not relax during the application of the massage technique. Semen was evaluated for volume, color, pH, spermatozoa concentration, total spermatozoa number, spermatozoa motility, and fraction of living spermatozoa. Additionally, spermatozoa were examined for pathomorphologic abnormalities.

Psittacine beak and feather disease virus in budgerigars and ring-neck parakeets in South Africa.

Psittacine beak and feather disease (PBFD) is a common disease of the psittacine species and is caused by the psittacine beak and feather disease virus (PBFDV). In this study the occurrence of the disease in ring-neck parakeets and budgerigars in South Africa suffering from feathering problems, using polymerase chain reaction as a diagnostic test was investigated. The genetic variation between viral isolates was also studied. Results indicate that PBFDV can be attributed to being the cause of feathering problems in some of the ring-neck parakeets and budgerigars in South Africa. Genetic variation of isolates occurs between species and individuals. A cheap and easy to use method of blood sample collection on filter paper for diagnostic purposes was also evaluated. It proved to be less stressful to the birds and did not inhibit further processes.

Evidence of unique genotypes of beak and feather disease virus in southern Africa.

Psittacine beak and feather disease (PBFD), caused by Beak and feather disease virus (BFDV), is the most significant infectious disease in psittacines. PBFD is thought to have originated in Australia but is now found worldwide; in Africa, it threatens the survival of the indigenous endangered Cape parrot and the vulnerable black-cheeked lovebird. We investigated the genetic diversity of putative BFDVs from southern Africa. Feathers and heparinized blood samples were collected from 27 birds representing 9 psittacine species, all showing clinical signs of PBFD. DNA extracted from these samples was used for PCR amplification of the putative BFDV coat protein (CP) gene. The nucleotide sequences of the CP genes of 19 unique BFDV isolates were determined and compared with the 24 previously described sequences of BFDV isolates from Australasia and America. Phylogenetic analysis revealed eight BFDV lineages, with the southern African isolates representing at least three distinctly unique genotypes; 10 complete genome sequences were determined, representing at least one of every distinct lineage. The nucleotide diversity of the southern African isolates was calculated to be 6.4% and is comparable to that found in Australia and New Zealand. BFDVs in southern Africa have, however, diverged substantially from viruses found in other parts of the world, as the average distance between the southern African isolates and BFDV isolates from Australia ranged from 8.3 to 10.8%. In addition to point mutations, recombination was found to contribute substantially to the level of genetic variation among BFDVs, with evidence of recombination in all but one of the genomes analyzed.

Analysis of the beak and feather disease viral genome indicates the existence of several genotypes which have a complex psittacine host specificity.

A study was made of the phylogenetic relationships between fifteen complete nucleotide sequences as well as 43 nucleotide sequences of the putative coat protein gene of different strains belonging to the virus species Beak and feather disease virus obtained from 39 individuals of 16 psittacine species. The species included among others, cockatoos ( Cacatuini), African grey parrots ( Psittacus erithacus) and peach-faced lovebirds ( Agapornis roseicollis), which were infected at different geographical locations, within and outside Australia, the native origin of the virus. The derived amino acid sequences of the putative coat protein were highly diverse, with differences between some strains amounting to 50 of the 250 amino acids. Phylogenetic analysis demonstrated that the putative coat gene sequences form six clusters which show a varying degree of psittacine species specificity. Most, but not all strains infecting African grey parrots formed a single cluster as did the strains infecting the cockatoos. Strains infecting the lovebirds clustered with those infecting such Australasian species as Eclectus roratus, Psittacula kramerii and Psephotus haematogaster. Although individual birds included in this study were, where studied, often infected by closely related strains, infection by highly diverged trains was also detected. The possible relationship between BFD viral strains and clinical disease signs is discussed.

Recombinant expression of a truncated capsid protein of beak and feather disease virus and its application in serological tests

Beak and feather disease virus (BFDV) causes severe disease characterized by irreversible feather disorders and severe immunosuppression in many psittacine species. BFDV cannot be propagated in tissue or cell cultures, rendering virus propagation and thus diagnosis rather difficult. To develop reliable diagnostic methods, the region encoding the BFDV capsid protein C1 was cloned from an infected sulphur-crested cockatoo (Cacatua galerita). Phylogenetic analysis showed this gene had 76.3 to 83.2% amino acid identity to published sequences. No protein was detected after induction of full-length C1 expression in Escherichia coli. However, deletion of an amino-terminal arginine-rich sequence facilitated expression. C139–244-His, a polyhistidine-tailed variant of this protein, was purified and used for immunization of chickens. The immune sera detected C1 with an apparent molecular weight of 27 kDa in western blots of organ homogenates of BFDV-infected birds. Using C139–244-His as antigen, 11 psittacine sera were tested for the presence of BFDV-specific antibodies by enzyme-linked immunosorbent assay and immunoblotting. The results obtained correlated well with the BFDV-specific haemagglutination inhibition activity of the sera, suggesting C139–244-His has value as a recombinant antigen for BFDV-specific serological tests.

Serum concentrations of ionized calcium, vitamin D3, and parathyroid hormone in captive thick-billed parrots (Rhynchopsitta pachyrhyncha).

Serum collected from 68 thick-billed parrots (Rhynchopsitta pachyrhyncha) from 15 institutions was analyzed for ionized Ca (iCa), total Ca (tCa), P, total protein (TP), albumin (Alb), parathyroid hormone (PTH), and vitamin D3. Values were not distributed normally; 95% frequency intervals were as follows: iCa (0.82-1.3 mmol/L), tCa (1.37-2.09 mmol/L,), P (0.35-1.75 mmol/L), TP (21-39 g/L), Alb (9-13 g/L), PTH (0-65.68 pmol/L), and vitamin D3 (5.2-51 nmol/L). Sixty percent (+/-7.5%) of tCa was ionized. Female thick-billed parrots had significantly higher mean iCa (1.11 mmol/L, n = 22) than male thick-billed parrots (1.05 mmol/L, n = 32). tCa and iCa values in thick-billed parrots were lower than the reported values for other psittacine species. A significant positive linear relationship existed between Alb-TP and iCa-tCa ratios. A significant inverse linear relationship was also identified between the tCa-P ratio and PTH. These findings are consistent with known domestic avian Ca physiology.

Nucleotide sequence analysis of a C1 gene fragment of psittacine beak and feather disease virus amplified by real-time polymerase chain reaction indicates a possible existence of genotypes

To investigate sequence diversity of psittacine beak and feather disease virus, samples collected from 31 psittacine species with or without clinical signs were tested for the presence of the viral genome. A real-time polymerase chain reaction was developed amplifying a 202 base pair fragment of the region encoding the capsid protein C1 and detecting 100 to 1000 genome equivalents. The nucleotide sequences of the polymerase chain reaction products showed 84.1 to 100% identity with no consistent pattern with regard to the infected bird species. Amino acid exchanges were concentrated mainly in five of the 42 deduced positions. Sequences obtained from an outbreak of acute beak and feather disease in lories clustered in a separate branch of a phylogenetic tree. Sequences in samples from African grey parrots with feather disorders grouped together, whereas those from the same species with immunosuppression clustered in other branches. These results indicate the possible existence of beak and feather disease virus genotypes.

Diagnosis and management of viral diseases in psittacine birds

AVIAN species are susceptible to a wide range of viral diseases. With the increasing trade in psittacine species worldwide, more and more of these viruses are making their way to...

Practical avian necropsy

This article is a review of the necropsy techniques utilized in birds with emphasis on psittacine and passerine species. The aim of this article is to assist the practitioner in systematically performing a gross necropsy in the veterinary practice setting and collecting and submitting appropriate samples with the goal of arriving at meaningful diagnoses. Common disease entities are discussed along with the tissues and other samples required for definitive diagnosis of these disorders.

Evidence for specificity of psittacine beak and feather disease viruses among avian hosts

Beak and feather disease is a major avian disease of both captive and wild parrot and cockatoo populations. Clinical signs include beak elongation and abnormal growth, together with weight loss and in some individuals the disease is fatal. We investigated the relationship between viral genotypes and their hosts in order to test for a positive association between distinct viral genomes and avian species. Specifically, we used the polymerase chain reaction (PCR) to amplify and sequence a 605-nucleotide (nt) segment of a coding region in the Beak and Feather Disease Virus (BFDV) genome. Feather and blood samples from 25 caged birds representing 10 species were assayed and the BFDV was detected in 21 samples from New Zealand. A phylogenetic analysis of DNA sequences from 17 specimens together with previously published sequences from Australian “isolates” revealed three lineages present in New Zealand. One viral lineage was found in six cockatoos representing two species (designated CT), a second lineage was detected in a budgerigar (designated BG), and a third was found in 10 lorikeets representing seven species (designated LK). This distinctive clustering pattern of viral sequences with groups of psittacine species indicates a genotypic association between the virus and these hosts.

Influence of environmental variability on the growth of Lilac‐crowned Parrot nestlings

Growth rate parameters were analysed for Lilac‐crowned Parrot Amazona finschi nestlings in the tropical dry forest of the Reserva de la Biosfera Chamela‐Cuixmala, Mexico. Growth rates for psittacine species follow the inverse relation with body mass observed for neotropical landbirds, with larger parrot species exhibiting slower growth rates. There was significant variation between years in size and growth rates of Lilac‐crowned Parrot nestlings with nestlings exhibiting slower growth rates in 1996 than in 1997. Food abundance for parrots also varied significantly between years, with greater food availability during the 1997 breeding season than that of 1996. The increased size and growth rates of nestlings in 1997 may have reflected this, and suggests the potential influence of environmental variability on parrot reproduction, particularly in such a markedly seasonal habitat.

Seasonal variation in occurrence of macaws along a rainforest river

Abstract Seasonal variations in occurrence of the Blue-and-yellow (Ara ararauna), Red-and-green (A. chloroptera), and Scarlet (A. macao) Macaw were evaluated in the floodplain rainforest of the Manu Biosphere Reserve, southeast Peru. One-hour surveys of macaws were conducted while traveling along the Rio Manu in a motorized canoe during both the dry and rainy season. There was a significant three-fold decline in the number of macaws encountered during the dry season compared to the rainy season. Encounter rates also varied significantly among macaw species, and may be due to behavioral characteristics or habitat preferences of species. Rapid or short-term surveys used to establish trade quotas and the status of species may be susceptible to biases and inaccuracies resulting from seasonal variations and behavioral characteristics of psittacine species.