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At least 19 recordsLinked to original sources
PubMed2006

Tissue distribution of psittacid herpesviruses in latently infected parrots, repeated sampling of latently infected parrots and prevalence of latency in parrots submitted for necropsy.

Psittacid herpesvirus-1 (PsHV-1) is the cause of an acute fatal disease in parrots and is implicated as the cause of papillomatous lesions of the digestive tract. Not all infections cause disease and some parrots are infected asymptomatically. Latently infected parrots are potential sources for virus dissemination. Tissues from parrots that died spontaneously with a history of coming from flocks where a PsHV-1 outbreak had occurred were examined for PsHV-1 DNA. Fourteen of 16 parrots examined were infected with at least 1 variant of PsHV-1; of these 13 (93%) had viral DNA in either or both the oral and cloacal mucosa, suggesting that most latently infected parrots could be detected by sampling these sites. Nine of 9 parrots shown to be infected 5 years prior to this study were positive again on repeat sampling and were infected with the same virus genotype. Opportunistic sampling of parrots submitted for diagnostic necropsy indicated that the prevalence of PsHV-1 in parrots in the sampled population was approximately 9.3%. PsHV-1 genotypes 1, 2, and 3 were found in these birds, but genotype 4 was not. Six necropsy specimens were found to be infected with two PsHV-1 genotypes and it was concluded that infection with one serotype did not protect against infection with another. Psittacid herpesvirus 2 (PsHV-2) was identified in 4 African grey parrots and a blue and gold macaw. Prior to this study PsHV-2 had only been found in African grey parrots.

Alphaherpesvirinae↗
PubMed1996

Effects of mydriatic agents in cockatoos, African gray parrots, and Blue-fronted Amazon parrots.

OBJECTIVE: To compare, in psittacines, the mydriatic effects of several topically applied curariform, sympathomimetic, and parasympatholytic drugs with and without the addition of surface-acting penetrating agents. DESIGN: Prospective, randomized controlled trial. ANIMALS: 10 adult cockatoos (Cacatua sulphurea subspecies), 2 adult African gray parrots (Psittacus erithacus), and 3 adult Blue-fronted Amazon parrots (Amazona aestiva). PROCEDURE: Three curariform drugs (d-tubocurarine, pancuronium, and vecuronium bromide) and 2 autonomic drugs (atropine and phenylephrine hydrochloride) were evaluated. Drugs were tested with and without the addition of a surface-acting penetrating agent, either saponin or benzalkonium chloride. The agent that resulted in the most significant change in pupillary diameter with the fewest systemic side effects in the cockatoos then was evaluated for its effects in the African gray parrots and the Blue-fronted Amazon parrots. During each drug trial, 1 eye was randomly selected to receive the control drug (0.9% NaCl), and the opposite eye was selected to receive the test drug. Each pupil was videotaped 5 (cockatoos only), 15, 30, 45, 60, and 75 minutes after treatment. Pupil diameters were measured by use of a computerized image analysis system. Data for pupil size were analyzed by means of repeated measures ANOVA. RESULTS: Vecuronium without the addition of a surface-acting penetrating agent produced the most consistent and greatest pupillary dilatation in all 3 species with the fewest systemic side effects. CLINICAL IMPLICATIONS: Vecuronium is potentially a clinically useful, topical mydriatic agent for use in avian species. Documented differences in the prevalence of systemic side effects between species suggests that caution should be applied when applying this drug bilaterally.

Animals↗
PubMed2005

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

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.

Animals↗
PubMed2003

The skull development of parrots with special reference to the emergence of a morphologically unique cranio-facial hinge.

The order Psittaciformes (parrots) has unique morphological features in the head that are evolutionarily novel. To better understand the unique evolution of the head in parrots, the developmental pattern of the skull of the budgerigar (Melopsittacus undulatus) was initially described on the basis of transparent skeletal specimens. Although the fundamental pattern of the skull development of birds is conserved in parrots, some differences were observed between parrots and other groups of birds. In parrots, the vacuity in the interorbital septum did not emerge throughout ontogeny, in contrast to other lineages of birds, for example Galliformes and Coliiformes. This feature seems to be concerned with the attachment of the unique jaw muscle of parrots, M. ethmomandibularis, to the interorbital septum. In spite of a prokinetic skull, the cranio-facial hinge of parrots was brought about by secondary transformation of dermal bones unlike that of birds with a standard prokinetic skull (e.g. Corvus) in which the nasal-frontal suture directly becomes a hinge of bending. To further understand the evolution of "pseudoprokinesis" in parrots, the construction of a robust avian phylogeny is desired. The parrot-specific suborbital arch and cranio-facial hinge are not seen until birds leave the nest and can feed themselves. In conclusion, these structures are considered to be essential for eating hard and/or large meals.

Adaptation, Physiological↗
PubMed1999

Reproductive management of captive parrots.

Studies of the behavior of Amazon parrots throughout a reproductive trial indicate that activities such as food gathering, which may occupy large fractions of the activity budget of wild parrots, occupy little time in captivity. This may be one factor contributing to the large percentage of time during which Amazon parrots are generally inactive in typical captive conditions. The extent of inactivity in captive Amazons creates an open time niche wherein enrichment devices might play a role in improving their well being. Studies of the reproductive endocrinology and the behavior of parrots suggest that hand rearing may impair adult fertility and nest box use. Hand rearing may also cause adult Cockatiels to lay eggs on cage floors rather than in nest boxes. However, the use of nest boxes with oversized nest entrances can be very effective in alleviating chronic floor laying in Cockatiels. Another egg-laying problem in Cockatiels, unwanted egg laying, can be prevented by the use of long-acting formulations of the superactive GnRH agonist, leuprolide acetate, which presumably [figure: see text] acts in birds, as in mammals, by down-regulating pituitary GnRH receptors. Manipulations to limit the increases in prolactin normally seen during incubation in poultry can significantly increase egg production. As clutch size in Cockatiels may also be limited by rising prolactin levels, such manipulations may be effective in stimulating egg production in parrots. An alternative approach for increasing flock egg production is to place foster eggs in nests of Cockatiel pairs that are slow to lay. This technique stimulates males to increase their nest-oriented behavior and, subsequently, may stimulate egg laying in some females that might not otherwise have laid eggs. The parental phases of reproduction in Amazon parrots are often a time of heightened aggressiveness towards humans, but low levels of serum testosterone in males during that time suggest that this particular interspecies aggressiveness may not be dependent on elevated testosterone levels. Occasional human handling during the nestling stage may produce a degree of tameness comparable with hand-reared chicks, yet not impair adult reproductive performance. Such handling may also alter the immune status of captive parrots, and possibly reduce the serum corticosterone response to handling. If so, occasional human handling during the nestling stage could improve the adaptation of parrots to captivity.

Animal Husbandry↗
PubMed2006

Phylogenetic relationships and historical biogeography of neotropical parrots (Psittaciformes: Psittacidae: Arini) inferred from mitochondrial and nuclear DNA sequences.

Previous hypotheses of phylogenetic relationships among Neotropical parrots were based on limited taxon sampling and lacked support for most internal nodes. In this study we increased the number of taxa (29 species belonging to 25 of the 30 genera) and gene sequences (6388 base pairs of RAG-1, cyt b, NADH2, ATPase 6, ATPase 8, COIII, 12S rDNA, and 16S rDNA) to obtain a stronger molecular phylogenetic hypothesis for this group of birds. Analyses of the combined gene sequences using maximum likelihood and Bayesian methods resulted in a well-supported phylogeny and indicated that amazons and allies are a sister clade to macaws, conures, and relatives, and these two clades are in turn a sister group to parrotlets. Key morphological and behavioral characters used in previous classifications were mapped on the molecular tree and were phylogenetically uninformative. We estimated divergence times of taxa using the molecular tree and Bayesian and penalized likelihood methods that allow for rate variation in DNA substitutions among sites and taxa. Our estimates suggest that the Neotropical parrots shared a common ancestor with Australian parrots 59 Mya (million of years ago; 95% credibility interval (CrI) 66, 51 Mya), well before Australia separated from Antarctica and South America, implying that ancestral parrots were widespread in Gondwanaland. Thus, the divergence of Australian and Neotropical parrots could be attributed to vicariance. The three major clades of Neotropical parrots originated about 50 Mya (95% CrI 57, 41 Mya), coinciding with periods of higher sea level when both Antarctica and South America were fragmented with transcontinental seaways, and likely isolated the ancestors of modern Neotropical parrots in different regions in these continents. The correspondence between major paleoenvironmental changes in South America and the diversification of genera in the clade of amazons and allies between 46 and 16 Mya suggests they diversified exclusively in South America. Conversely, ancestors of parrotlets and of macaws, conures, and allies may have been isolated in Antarctica and/or the southern cone of South America, and only dispersed out of these southern regions when climate cooled and Antarctica became ice-encrusted about 35 Mya. The subsequent radiation of macaws and their allies in South America beginning about 28 Mya (95% CrI 22, 35 Mya) coincides with the uplift of the Andes and the subsequent formation of dry, open grassland habitats that would have facilitated ecological speciation via niche expansion from forested habitats.

Animals↗
PubMed1997

Investigation of parrot papillomavirus in cloacal and oral papillomas of psittacine birds.

Cloacal and oral papillomas from 27 psittacine birds of various species were examined for the presence of parrot papillomavirus by DNA in situ hybridization, DNA in situ polymerase chain reaction, and nested polymerase chain reaction. Parrot papillomavirus was detected in one oral papilloma from an African grey parrot by all three techniques. In addition, rare basophilic intranuclear inclusions were observed by light microscopy in tissue sections of the oral papilloma from this parrot. The remaining lesions were negative for parrot papillomavirus DNA. This study suggests that parrot papillomavirus may be involved in the development of papillomas in African grey parrots, but apparently is not responsible for development of similar lesions in unrelated species of psittacine birds.

Journal Article↗
PubMed2004

Carotenoid pigments and the selectivity of psittacofulvin-based coloration systems in parrots.

Carotenoid pigments are commonly used as colorants of feathers and bare parts by birds. However, parrots (Aves: Psittaciformes) use a novel class of plumage pigments (called psittacofulvins) that, like carotenoids, are lipid-soluble and red, orange, or yellow in color. To begin to understand how and why parrots use these pigments and not carotenoids in their feathers, we must first describe the distribution of these two types of pigments in the diet, tissues, and fluids of these birds. Here, we studied the carotenoid content of blood in five species of parrots with red in their plumage to see if they show the physiological ability to accumulate carotenoids in the body. Although Scarlet (Ara macao) and Greenwing Macaws (Ara chloroptera) and Eclectus (Eclectus roratus), African Gray (Psittacus erithacus) and Blue-fronted Amazon (Amazona aestiva) Parrots all use psittacofulvins to color their feathers red, we found that they also circulated high concentrations of both dietary (lutein, zeaxanthin, beta-cryptoxanthin) and metabolically derived (anhydrolutein, dehydrolutein) carotenoids through blood at the time of feather growth, at levels comparable to those found in many other carotenoid-colored birds. These results suggest that parrots have the potential to use carotenoids for plumage pigmentation, but preferentially avoid depositing them in feathers, which is likely under the control of the maturing feather follicle. As there is no evidence of psittacofulvins in parrot blood at the tune of feather growth, we presume that these pigments are locally synthesized by growing feathers within the follicular tissue.

Animals↗
PubMed2005

Extensive consumption of Tabebuia aurea (Manso) Benth. & Hook. (Bignoniaceae) nectar by parrots in a Tecoma savanna in the southern Pantanal (Brazil).

Neotropical parrots forage for various food items such as seeds, fruit pulp, flowers, young leaves, and even arthropods. While foraging, many species wander over large areas that include both open and closed habitats. In this study, I examined parrot foraging activity during a brief synchronous and massive flowering in August 1998 in a tecoma savanna (dominated by Tabebuia aurea) in the southern Pantanal. Six parrot species, ranging from the small Brotogeris chiriri to the large Amazona aestiva, foraged for T. aurea nectar, but Nandayus nenday was by far the major nectar consumer, and the results of each of their visits, like those of the other species, was damage of a substantial proportion of the existing flower crop. Parrots foraged mostly during the afternoon, when nectar concentration tended to be higher. Nevertheless, compared to bird-pollinated flowers, which produce copious nectar, T. aurea had a smaller mean nectar volume per flower. Hence, presumably the amount of damage wreaked by these parrots resulted from their efforts to obtain part of their daily energy and water requirements. Thus, the synchronous and massive flowering occurring in such a brief period in the dry season may be related to, among other factors, the necessity of satiating predators such as parrots, which are still abundant in the Pantanal.

Animals↗
PubMedDate not supplied

Severity of atherosclerosis in parrots in relation to the intake of alpha-linolenic acid.

Atherosclerosis is a common disease among parrots, but little is known about possible risk factors. Important risk factors in humans are an elevated plasma cholesterol concentration and increased platelet aggregation; high intakes of polyunsaturated fatty acids have beneficial effects. In this study, we tried to establish a relationship, if any, between dietary fatty acids and the severity of atherosclerosis in parrots. We collected dead parrots and scored the degree of atherosclerosis in the beginning of the aorta and the brachiocephalic arteries. It was not possible to assess the intake of fatty acids with food questionnaires so fatty acid composition of adipose tissue and breast muscle had to be used as an index of the dietary fatty acid composition. In all, 202 birds were collected. Gender was not related with atherosclerosis, but the degree of atherosclerosis increased with age and among the various species; African grey parrots appeared to be the most susceptible. The contents of linoleic acid in breast muscle or adipose tissue were not associated with the severity of atherosclerosis. For the relative percentage of alpha-linolenic acid in either breast muscle (P = 0.09; n = 175) or adipose tissue (P = 0.056; n = 21), a borderline significant relation with the degree of atherosclerosis was found. Parrots without atherosclerosis had significantly higher levels of alpha-linolenic acid than did the other animals. On the basis of these data, we suggest tentatively that a high dietary intake of alpha-linolenic acid protects against the development of atherosclerosis in parrots.

Adipose Tissue↗
PubMed2004

Morphogenesis of parrot jaw muscles: understanding the development of an evolutionary novelty.

Parrots have developed novel head structures in their evolutionary history. The appearance of two new muscles for strong jaw adduction is especially fascinating in developmental and evolutionary contexts. However, jaw muscle development of parrots has not been described, despite its uniqueness. This report first presents the normal developmental stages of the cockatiel (Nymphicus hollandicus), comparable to that of the chick. Next, the peculiar skeletal myogenesis in the first visceral arch of parrots is described, mainly focusing on the development of two new jaw muscles. One of the parrot-specific muscles, M. ethmomandibularis, was initially detected at Nymphicus Stage 28 (N28) as the rostral budding of M. pterygoideus. After N32, the muscle significantly elongates rostrodorsally toward the interorbital septum, following a course lateral to the palatine bone. Another parrot-specific muscle, M. pseudomasseter, was first recognized at N36. The muscle branches off from the posteromedial M. adductor mandibulae externus and grows in a dorsolateral direction, almost covering the lateral surface of the jugal bar. The upper tip of the muscle is accompanied by condensed mesenchyme, which seems to be derived from cephalic neural crest cells.

Animals↗
PubMed2004

Psittacid herpesviruses associated with mucosal papillomas in neotropical parrots.

Mucosal papillomas are relatively common lesions in several species of captive neotropical parrots. They cause considerable morbidity and in some cases, result in mortality. Previous efforts to identify papillomavirus DNA and proteins in these lesions have been largely unsuccessful. In contrast, increasing evidence suggests that mucosal papillomas may contain psittacid herpesviruses (PsHVs). In this study, 41 papillomas from 30 neotropical parrots were examined by PCR with PsHV-specific primers. All 41 papillomas were found to contain PsHV DNA. This 100% prevalence of PsHV infection in the papilloma population was found to be significantly higher than PsHV infection prevalence observed in other surveys of captive parrots. PsHV genotypes 1, 2, and 3, but not 4 were found in these lesions. Psittacus erithacus papillomavirus DNA and finch papillomavirus DNA were not found in the papillomas. A papilloma from a hyacinth macaw (Anodorhynchus hyacinthinus) was found to contain cells that had immunoreactivity to antiserum made to the common antigenic region of human papillomavirus (HPV) L1 major capsid protein. However, four other mucosal papillomas were negative for this immunoreactivity, and negative control tissues from a parrot embryo showed a similar staining pattern to that seen in the cloaca papilloma of the hyacinth macaw, strongly suggesting that the staining seen in hyacinth macaw papilloma was nonspecific. Based on these findings, it was concluded that specific genotypes of PsHV play a direct role in the development of mucosal papillomas of neotropical parrots and there is no evidence to suggest the concurrent presence of a papillomavirus in these lesions.

Animals↗
PubMed2000

Comparative DNA sequence analysis of genetic variation in the African grey parrot, Psittacus erythacus.

Comparative genome analysis promises to provide an insight into avian species that have been very little studied. To test the feasibility of this approach, we investigated the use of heterologous primers to generate single nucleotide polymorphisms (SNP) in the African grey parrot, Psittacus erythacus, using primers specific for chicken and turkey DNA fragments. Three of the primers were specific for three expressed sequence tagged sites in the turkey and the fourth for a chicken proteoglycan core protein-like DNA sequence. A total of about 2200 bp of the parrot genome was evaluated for DNA sequence variation. Seven SNPs were identified and confirmed by Mendelian segregation. The frequency distribution of the most common nucleotide at each SNP locus in an unrelated group of parrots ranged from 0.84 to 0.97. The percent similarity of each parrot sequence to the reference sequence was inconsistent and ranged from zero to 100%. The primers as well as the nucleotide variants described represent valuable resources for genetic analysis in the parrot.

Animals↗
PubMed1992

Application of DNA fingerprinting to the recovery program of the endangered Puerto Rican parrot.

The Puerto Rican parrot was reduced to approximately 13 animals in 1975 and as a conservation measure, a captive population was established from a few founders taken from the wild between 1973 and 1983. The number of successful breeding pairs in captivity has been low, and the captive breeding program has not been as productive as that of the closely related Hispaniolan parrot. Therefore, a genetic study was initiated to examine the relative levels of relatedness of the captive founders using levels of bandsharing in DNA fingerprints. Unrelated captive founder Puerto Rican parrots had the same average level of bandsharing (0.41) as second-degree relatives of the Hispaniolan parrot (0.38, P > 0.05), with an inbreeding coefficient of 0.04. High levels of bandsharing (> 40%) between pairs of males and females correlated with reproductive failure, suggesting that inbreeding depression is partly responsible for the low number of breeding pairs. Consequently, DNA profiling can be used to guide the captive breeding program for the Puerto Rican parrot, and other endangered species, by identifying pairs of males and females with low levels of bandsharing.

Animals↗
PubMed2002

Spironucleosis in Australian king parrots (Alisterus scapularis).

OBJECTIVE: To describe a syndrome of wasting, diarrhoea and mortality in Australian king parrots (Alisterus scapularis). DESIGN: Field observations and laboratory examinations. Procedure Pathological examinations were performed on 50 Australian king parrots with wasting and diarrhoea. Wet preparations of intestinal contents were examined by light microscopy. Tannins were extracted from acorns (Quercus sp) and tested for toxicity in mice. CLINICAL SIGNS AND EPIDEMIOLOGY: A syndrome of wasting, diarrhoea and mortality was observed in wild juvenile Australian king parrots in eastern Australia from 1984 to 2000. Sporadic cases and outbreaks of disease occurred from May to September in New South Wales, the Australian Capital Territory and Victoria. Outbreaks in the Australian Capital Territory in 1990 and 1991 were associated with parrots congregating to feed on acorns. Most affected birds failed to respond to treatment with dimetridazole and died 1 to 14 days after hospitalisation. Selected cases recovered following treatment with metronidazole. PATHOLOGY: Affected birds were emaciated, with faecal matting of feathers around the cloaca and yellow-green fluid, foamy intestinal contents. Abundant motile Spironucleus trophozoites were observed in wet preparations of faeces of clinically affected birds and intestinal contents of birds examined within 1 h of death. Protozoa were detected histologically in crypts of Lieberkühn in the intestine in association with exudation of mucus (catarrhal enteritis) or lymphoplasmacytic enteritis. Toxicology Tannin extracts from acorns induced periacinar hepatic necrosis in mice. CONCLUSION: Wasting, diarrhoea and mortality in wild juvenile Australian king parrots were associated with Spironucleus-like protozoa in the intestine. Acorns were not considered to be the cause of the syndrome.

Animals↗
PubMed2005

Distribution of unique red feather pigments in parrots.

In many birds, red, orange and yellow feathers are coloured by carotenoid pigments, but parrots are an exception. For over a century, biochemists have known that parrots use an unusual set of pigments to produce their rainbow of plumage colours, but their biochemical identity has remained elusive until recently. Here, we use high-performance liquid chromatography to survey the pigments present in the red feathers of 44 species of parrots representing each of the three psittaciform families. We found that all species used the same suite of five polyenal lipochromes (or psittacofulvins) to colour their plumage red, indicating that this unique system of pigmentation is remarkably conserved evolutionarily in parrots. Species with redder feathers had higher concentrations of psittacofulvins in their plumage, but neither feather colouration nor historical relatedness predicted the ratios in which the different pigments appeared. These polyenes were absent from blood at the time when birds were replacing their colourful feathers, suggesting that parrots do not acquire red plumage pigments from the diet, but instead manufacture them endogenously at growing feathers.

Animals↗