Domestic Canaries Research Articles

Sex-and Region-Dependent Expression of the Autism-Linked ADNP Correlates with Social- and Speech-Related Genes in the Canary Brain

The activity-dependent neuroprotective protein (ADNP) syndrome is an autistic-like disorder, instigated by mutations in ADNP. This syndrome is characterized by developmental delays, impairments in speech, motor function, abnormal hearing, and intellectual disabilities. In the Adnp-haploinsufficient mouse model, many of these impediments are evident, appearing in a sex-dependent manner. In zebra finch songbird (ZF; Taeniopygia guttata), an animal model used for song/language studies, ADNP mRNA most robust expression is observed in the cerebrum of young males, potentially corroborating with male ZF exclusive singing behavior and developed cerebral song system. Herein, we report a similar sex-dependent ADNP expression profile, with the highest expression in the cerebrum (qRT-PCR) in the brain of another songbird, the domesticated canary (Serinus canaria domestica). Additional analyses for the mRNA transcripts of the ADNP regulator, vasoactive intestinal peptide (VIP), sister gene ADNP2, and speech-related Forkhead box protein P2 (FoxP2) revealed multiple sex and brain region-dependent positive correlations between the genes (including ADNP). Parallel transcript expression patterns for FoxP2 and VIP were observed alongside specific FoxP2 increase in males compared with females as well as VIP/ADNP2 correlations. In spatial view, a sexually independent extensive form of expression was found for ADNP in the canary cerebrum (RNA in situ hybridization). The songbird cerebral mesopallium area stood out as a potentially high-expressing ADNP tissue, further strengthening the association of ADNP with sense integration and auditory memory formation, previously implicated in mouse and human.

Beak Line and Eye Alignment as Phenotypic Sexing for Domestic Canaries (Serinus canaria)

Phenotypic sexing of birds is a common practice among the songbird-keeping community, yet it is based on non-reputable information. This study aims to determine the sex of canaries (Serinus canaria) based on the alignment of the eye with the beak line. A total of 26 samples, consisting of six samples of one-month-old canaries (three males and three females based on PCR examination), 20 samples of six-month-old canaries (ten proven breeding pairs) were used in this study. The birds' heads were photographed from the sides, and then the positions of the eyes were compared with the shadow alignment of the beak. The results provided that five young birds and ten adult birds have a beak line alignment under the eye, while ten adult birds and one young bird have a beak line alignment across the eye. The accuracy of sexing using this method was 100% for both female and male adult canaries. However, this result could not be applied to sample that are not yet sexually mature, as two young male birds were found to have beak alignment below the eye. It can be concluded that sexing adult canaries can be performed by observing the eye and beak line's alignment.

From the Dawn Chorus to the Canary Choir

Birdsong is familiar but enigmatic: to some nothing but mechanical “instinct,” but so excessively exuberant that enthusiasts have linked the songs of birds to the development of the aesthetic sense. Where medieval scholars once saw the origins of music in the imitation of nature, by the Enlightenment birdsong was banished in the anthropocentric definition of art. In contrast to the philosophers, this paper focusses on human intervention in birdsong, focusing on the song of the domestic canary. The canary’s “contrived” song can be understood as a partnership between humans and birds, mediated by technology. Drawing on the European history of canary keeping, in Germany and Russia in particular, we turn first to the training of songbirds. Subsequently, we consider canaries as signature nonhuman performers, in spaces ranging from the home to the stage. Finally, we consider the role of technology, specifically recording and amplification, in making the canary’s song audible to audiences at a distance. The salutary hybridization of animal–human-machine contests the longstanding condescension of philosophers towards mechanical artifice and any contamination of the free beauties of nature.

Experimental Usutu Virus Infection in Domestic Canaries Serinus canaria.

Usutu virus (USUV) is a neurotropic flavivirus closely related to West Nile virus (WNV). Its enzootic cycle mainly involves mosquitoes and birds. Human infection can occur with occasional, but sometimes severe, neurological complications. Since its emergence and spread in Europe over the last two decades, USUV has been linked to significant avian outbreaks, especially among Passeriformes, including European blackbirds (Turdus merula). Strikingly, no in vivo avian model exists so far to study this arbovirus. The domestic canary (Serinus canaria) is a passerine, which is considered as a highly susceptible model of infection by WNV. Here, we experimentally challenged domestic canaries with two different doses of USUV. All inoculated birds presented detectable amounts of viral RNA in the blood and RNA shedding via feathers and droppings during the early stages of the infection, as determined by RT-qPCR. Mortality occurred in both infected groups (1/5 and 2/5, respectively) and was not necessarily correlated to a pure neurological disease. Subsequent analyses of samples from dead birds showed histopathological changes and virus tropism mimicking those reported in naturally infected birds. A robust seroconversion followed the infection in almost all the surviving canaries. Altogether, these results demonstrate that domestic canaries constitute an interesting experimental model for the study of USUV pathogenesis and transmission.

Genetic Basis of De Novo Appearance of Carotenoid Ornamentation in Bare Parts of Canaries

Unlike wild and domestic canaries (Serinus canaria), or any of the three dozen species of finches in genus Serinus, the domestic urucum breed of canaries exhibits bright red bills and legs. This novel trait offers a unique opportunity to understand the mechanisms of bare-part coloration in birds. To identify the mutation producing the colorful phenotype, we resequenced the genome of urucum canaries and performed a range of analyses to search for genotype-to-phenotype associations across the genome. We identified a nonsynonymous mutation in the gene BCO2 (beta-carotene oxygenase 2, also known as BCDO2), an enzyme involved in the cleavage and breakdown of full-length carotenoids into short apocarotenoids. Protein structural models and in vitro functional assays indicate that the urucum mutation abrogates the carotenoid-cleavage activity of BCO2. Consistent with the predicted loss of carotenoid-cleavage activity, urucum canaries tended to have increased levels of full-length carotenoid pigments in bill tissue and reduced levels of carotenoid-cleavage products (apocarotenoids) in retinal tissue compared with other breeds of canaries. We hypothesize that carotenoid-based bare-part coloration might be readily gained, modified, or lost through simple switches in the enzymatic activity or regulation of BCO2 and this gene may be an important mediator in the evolution of bare-part coloration among bird species.

Experimental study of micro-habitat selection by ixodid ticks feeding on avian hosts

Mechanisms of on-host habitat selection of parasites are important to the understanding of host-parasite interactions and evolution. To this end, it is important to separate the factors driving parasite micro-habitat selection from those resulting from host anti-parasite behaviour. We experimentally investigated whether tick infestation patterns on songbirds are the result of an active choice by the ticks themselves, or the outcome of songbird grooming behaviour. Attachment patterns of three ixodid tick species with different ecologies and host specificities were studied on avian hosts. Ixodes arboricola, Ixodes ricinus and Ixodes frontalis were put on the head, belly and back of adult great tits (Parus major) and adult domestic canaries (Serinus canaria domestica) which were either restricted or not in their grooming capabilities. Without exception, ticks were eventually found on a bird’s head. When we gave ticks full opportunities to attach on other body parts – in the absence of host grooming – they showed lower attachment success. Moreover, ticks moved from these other body parts to the host's head when given the opportunity. This study provides evidence that the commonly observed pattern of ticks feeding on songbirds’ heads is the result of an adaptive behavioural strategy. Experimental data on a novel host species, the domestic canary, and a consistent number of published field observations, strongly support this hypothesis. We address some proximate and ultimate causes that may explain parasite preference for this body part in songbirds. The link found between parasite micro-habitat preference and host anti-parasite behaviour provides further insight into the mechanisms driving ectoparasite aggregation, which is important for the population dynamics of hosts, ectoparasites and the micro-pathogens for which they are vectors.

Characteristics of song, brain-anatomy and blood androgen levels in spontaneously singing female canaries

Females of many northern temperate songbird species sing sporadically. However, detailed descriptions of female song are rare. Here we report a detailed analysis of song in a small number of spontaneously-singing female domesticated canaries (Serinus canaria) under non-breeding, laboratory conditions in a large population of domesticated birds. In-depth analysis showed that these females sang rarely, and the spontaneous songs varied between and within birds over time. Furthermore, spontaneous female songs were distinct from songs of testosterone-induced singing female canaries and from songs of male canaries in both temporal and spectral features. Singing females had significantly elevated plasma androgen levels and a larger size of the major song controlling brain nuclei HVC (used as a proper name) and the robust nucleus of the arcopallium (RA) than non-singing females housed under similar conditions. The sporadically observed production of song and accompanying differences in brain anatomy in female canaries may thus depend on minute intraspecific differences in androgen levels.

Microscopic changes in the digestive organs of domestic canaries poisoned with canthaxanthin

Intoxication of canaries with canthaxanthin has been recorded more and more often since the late 1990s. This problem is related to active use of this substance for changing or increasing the colouration of this species of bird. For determining morphological changes during canthaxanthin toxicosis, we formed one control and three experimental groups of domestic canaries, which were given canthaxanthin in different doses. The material for microscopic surveys was isolated from the digestive organs of the examined birds; from this material, histological sections were prepared and stained with hematoxylin and eosin. According to the results of microscopic analysis, we determined that the intoxication of the organism of canaries with canthaxanthin causes a certain complex of changes at the tissue level. We found that canthaxanthin intoxication leads to chronic pathological processes in the digestive organs, both the digestive canal and digestive glands (pancreas, liver). In the organs of the digestive tract (glandular stomach or proventriculus, muscular stomach or gizzard, and the intestine) we found chronic catarrhal inflammation, and also proliferative processes – cellular infiltration of the stroma, overgrowth of the connective tissue. In some cases we also found distrophic processes such as keratinization of the epithelium of the mucous membrane of the glandular stomach. In the pancreas, except for edema of the stroma, no pathological processes were observed. In the liver, we found different types of dystrophy – protein (granular, hydropic) and fatty (infiltrational). With introduction of the highest doses of canthaxanthin used in the experiment, we determined a tendency towards exacerbation of pathological processes, because, apart from the already mentioned changes, we recorded manifestations of alteration (necrotic processes, disorders in blood circulation). Therefore, we proved that irrational use of canthaxanthin in canary-keeping is a factor that can negatively influence the health of these animals. Using the data we obtained, use of canthaxanthin in the diet of canaries can be correlated with their diet, thus avoiding risk of bird diseases. There is scope for further studies on the impact of canthaxanthin on other organs and the systems of the organs at microscopic level, as well as conducting biochemical and morphological analyses of blood, which would allow the creation of a new complete clinical-anatomical description of this pathology.

Increased genetic diversity of methicillin-resistant Staphylococcus aureus (MRSA) isolated from companion animals

The aim of the present study was to investigate the diversity of methicillin-resistant Staphylococcus aureus (MRSA) that originated from Austrian companion animals during the last five-year period. A total of 90 non-repetitive MRSA isolates were obtained during diagnostic activities from autumn 2013 to autumn 2018. They originated from horses (n = 62), cats (n = 13), dogs (n = 10), rabbits (n = 2), a domestic canary, a zoo-kept hammer-headed bat (Hypsignathus monstrosus) and a semi-captive northern bald ibis (Geronticus eremita). Antimicrobial susceptibility testing was performed. All isolates were mecA-positive and mecC-negative. The isolates were genotyped by SCCmec, spa and dru typing, Multiple-Locus Variable number of tandem repeat Analyses (MLVA), S. aureus DNA microarray, and whole-genome sequencing (WGS). Eight sequence types (STs - ST398, ST5275 (new ST), ST225, ST8, ST22, ST152, ST1, and ST45), three SCCmec types (II, IV, and V), sixteen spa types (t003, t008, t011, t015, t032, t034, t1381, t1928, t1985, t223, t334, t355, t430, t6447, t6867, and t7105), fourteen dru types (dt10a, dt10az, dt10q, dt10r, dt11a, dt5e, dt6j, dt9a, dt9ak, dt9g, and four new types dt8as, dt7ak, dt4j, dt14n), and thirty-five MLVA types were detected. WGS-based core genome MLST (cgMLST) displayed five main clusters. Compared to the time period 2004–2013, the results of the present study show not only a higher diversity among the MRSA isolates within the population of Austrian companion animals, but also the introduction of new clones. Although ST398 isolates remained predominant, mainly due to high presence of this lineage among horses, increasing isolation rates of human-associated MRSA clones were observed in cats and dogs.

Loss of Carotenoid Plumage Coloration Is Associated With Loss of Choice for Coloration in Domestic Canaries

Understanding the evolution of mating display traits and preferences for them is a major aim of behavioral and evolutionary ecology. However, isolating the specific traits used as mate choice criteria and the possible genetic underpinnings of both trait and preference has proven difficult, particularly in natural systems offering little experimental control over key variables. In this study, we used discrete color morphs of otherwise phenotypically identical domestic canaries (Serinus canaria) in a mate choice apparatus to test whether breeding-condition female canaries show preference for males of varying color phenotypes (yellow, white, red, or wild-type green), using spatial association as a proxy for choice. We also used synthesized vocal recordings to examine whether females in our population exhibited mate choice for song characteristics, as has been demonstrated in this species. Contrary to previous study, we found that neither white nor yellow females in our colony showed any preference for males associated with songs of differing quality, and yellow females also did not prefer supernormal red or wild-type green males over yellow males. However, yellow—but not white—females demonstrated a preference to associate with yellow males over white males. We hypothesize that preference for brightly colored mates is ancestral in domestic canaries, but that strong artificial selection for white females to reproduce successfully with white males has eliminated the preference for color (along with color itself) in the white canaries.

Detection of Avian Bornavirus in Wild and Captive Passeriformes in Brazil.

Avian bornaviruses (ABVs) are the causative agents of proventricular dilatation disease (PDD), a fatal neurologic disease considered to be a major threat to psittacine bird populations. We performed a reverse transcription PCR survey to detect the presence of canary avian bornavirus (CnBV) in birds of order Passeriformes related to different clinical manifestations, such as sudden death, neurologic signs, apathy, anorexia, excessive beak growth, and PDD. A total of 227 samples from captive and wild canaries were included, of which 80 samples were captive birds, comprising saffron finches (n = 71) and common canary (n = 9), and 147 samples were wild birds distributed among a variety of several species. Two samples from captive birds (2/80) were positive for ABV, and in wild birds, only one sample was positive for ABV. The positive samples were subjected to DNA sequencing, and only the CnBV-1 serotype was found, which was the first time it was detected outside of Germany (Austria/Hungary), where it was first detected in 2009. Phylogenetic analysis confirmed that avian bornavirus serotype CnBV-1 is present in order Passeriformes in Brazil.

Testing the resource trade-off hypothesis for carotenoid-based signal honesty using genetic variants of the domestic canary.

Carotenoid-based coloration in birds is widely considered an honest signal of individual condition, but the mechanisms responsible for condition dependency in such ornaments remain debated. Currently, the most common explanation for how carotenoid coloration serves as a reliable signal of condition is the resource trade-off hypothesis, which proposes that use of carotenoids for ornaments reduces their availability for use by the immune system or for protection from oxidative damage. However, two main assumptions of the hypothesis remain in question: whether carotenoids boost the performance of internal processes such as immune and antioxidant defenses, and whether allocating carotenoids to ornaments imposes a trade-off with such benefits. In this study, we tested these two fundamental assumptions using types of domestic canary (Serinus canaria domestica) that enable experiments in which carotenoid availability and allocation can be tightly controlled. Specifically, we assessed metrics of immune and antioxidant performance in three genetic variants of the color-bred canary that differ only in carotenoid phenotype: ornamented, carotenoid-rich yellow canaries; unornamented, carotenoid-rich 'white dominant' canaries; and unornamented, carotenoid-deficient 'white recessive' canaries. The resource trade-off hypothesis predicts that carotenoid-rich individuals should outperform carotenoid-deficient individuals and that birds that allocate carotenoids to feathers should pay a cost in the form of reduced immune function or greater oxidative stress compared with unornamented birds. We found no evidence to support either prediction; all three canary types performed equally across measures. We suggest that testing alternative mechanisms for the honesty of carotenoid-based coloration should be a key focus of future studies of carotenoid-based signaling in birds.

Evidencias moleculares de hibridación entre Serinus canaria domestica (L., 1758) y Spinus barbatus (Molina, 1782) (Aves: Fringillidae)

espanolEn este estudio se muestran evidencias moleculares de exito en la hibridacion entre Serinus canaria domestica (linnaeus, 1758) y Spinus barbatus (molina, 1782). Como parte de una secuencia de retrocruzamiento, se logro reproducir hibridos F2 a partir de hembras hibridas fertiles viables F1 x S. c. domestica. La F1 fue la descendencia entre P0 = Serinus c. domestica x Spinus barbatus. Las secuencias de nucleotidos de dos segmentos de ADN, citocromo b mitocondrial (Cyt b) y el receptor de tirosina quinasa muscular (MuSK) del ADN nuclear se obtuvieron de tres especimenes hibridos F2. Tanto las secuencias de Cyt b como de MuSK senalaron fuerte soporte filogenetico a la condicion genetica hibrida de los tres embriones F2. De esta manera la evidencia molecular refleja el exito en el cruce interespecifico entre S. barbatus con S. c. domestica y que es posible obtener hibridos fertiles viables F1 (en este caso hembras) y F2 entre estos dos linajes en poblaciones naturales. EnglishIn this study we show molecular evidences of success in hybridization between Serinus canaria domestica and Spinus barbatus. As part of a sequence of backcrossing we have achieved to reproduce F2 hybrids of fertile hybrid females F1 with parental S. c. domestica. F1 was the offspring between, P0 = S. c. domestica x S. barbatus. In this study the space where the observations and the breeding success are carried out between these species, they are described: is a room with the following measures; 4,45 m (lenghty) x 1,60 m (width) x 2,30 m (high), located in an urban building; specifically, glassed-balcony at a height of 10,60 m above ground level, facing some ornamental and exuberant canopy trees of Platanus orientalis (L., 1753) and with direct entrance of natural sunlight, in urban city of Santiago, Chile, where his perceptual world develops. We took care to keep the biotic and abiotic factors under control; specifically, incoming natural light, ambient vegetation and temperature. On the other hand, we fed the individuals appropriately and provided them with plenty of clean water to drink and get clean, where there were no predators. In sum, the individuals were kept in a healthy environment. The backcrossing between the male S. c. domestica (generation 0) bred with two viable hybrid F1 offspring females, it gave as resulted in a total of three independent generations of F2 hybrids (n = 12). All the individuals came out healthy, and none of them died, despite being inbred lineages. Three embryos representative of the F2 hybrids were sacrificed and deposited in 99% alcohol. Nucleotide sequences of two DNA segments, mitochondrial cytochrome b (Cyt b) and muscle-specific receptor tyrosine kinase (MuSK) gene of the nuclear DNA were obtained from three F2 hybrid specimens. The model of molecular evolution with the greatest adjustment to the data obtained by jModeltest was GTR + I + G (I = 0,1450, G = 0,0930), according to the phylogenetic analysis of mitochondrial DNA (Fig. 1a), the female progenitor P0 is S.c.domestica. This conclusion is based on the evi- dence that mitochondrial DNA in birds, as well as in most animal groups, is exclusively inherited through the maternal ways. The same analysis carried out with the nuclear MuSK gene shows that the parental male P0 of the embryos analyzed is very much related to S. barbatus (Fig. 1b). The Cyt b and MuSK region show strongly support to hybrids genetic condition of the three F2 embryos. Intergeneric hybrids are usually sterile, but it is worth noting that genera of Fringillidae are very closely related (the Family as a whole is only 12 million years old, and most genera in the terminal canary-siskin group are In addition, hybrids produced ex situ under controlled conditions would play an important role for reproductive success and subsequent interspecific viability. The main conclusions derived from this study are as follows: 1) The present report strongly indicates that hybridizations have occurred among S. c. canary x S. barbatus. 2) In this way the molecular evidence reflects and justifies the success in interspecific reproduction between S. barbatus with S. c. domestica and that it is possible to obtain viable fertile hybrids F1 (in this case females) and F2 between these two lineages, 3) And consequently the close genetic affinity between these two genera and the formation of hybrids in natural populations should not discard.

Phylogenetic evaluation of Macrorhabdus ornithogaster isolated from a case of canary (Serinus canaria)

Two dead birds from a flock of domestic canaries (Serinus canaria) were referred with a history of anorexia, weight loss, abdominal distension, and occasional mortality. A slightly enlarged liver and proventriculus were seen on the examination of the abdominal cavity. A large number of yeast resembling Macrorhabdus ornithogaster were observed on gram staining of the proventriculus mucosa. Pseudomonas aeruginosa was isolated on the microbial culture of the liver. The complete genomic sequence of the internal transcribed spacer 1 (ITS1) was determined in Macrorhabdus ornithogaster using panfungal primers. The alignment of the sequence obtained from this study with 6 GenBank deposited ITS1sequences of Macrorhabdus ornithogaster showed some repeated nucleotide substitutions. The complete ITS1 sequence of our study (MF993119) displayed a whole genetic similarity to ITS1 sequences of Macrorhabdus ornithogaster isolated from canaries and finches and clustered into a different group from ITS1 sequences of Macrorhabdus ornithogaster isolated from pssitacines. The ITS1 region is proposed as taxonomically informative for Macrorhabdus ornithogaster isolates from different hosts.

Consistency of female preference for male song in the domestic canary using two measures: Operant conditioning and vocal response

Variation of female preferences is often reported in the literature and could be related to an artefact derived from multiple different methods used. Thus, there is a need to evaluate the influence of different methods when assessing female preferences. The present study aims to compare female preferences obtained from an operant conditioning test and from female vocal responses to male song in the domestic canary (Serinus canaria). In an operant conditioning test, females had the possibility to choose between two keys; a peck on one key elicited a supposed very attractive canary song while a peck on the other key elicited a less attractive song. Meanwhile, female vocal responses were recorded. Our results revealed that female canaries preferred to peck on the key eliciting the attractive song and that they emitted more copulation calls in response to the attractive song compared to the less attractive song. This study shows the congruence of these two methods and further suggests that they are reliable to study female preferences in laboratory conditions.

Some biological and behavioral aspects of Amblyomma longirostre (Acari: Ixodidae) under laboratory and natural conditions

Amblyomma longirostre (Koch, 1844) has been reported as one of the most common ticks parasitizing wild animals in Brazil; however, information about its life cycle is inexistent, as well as information on its behavior in nature. In order to determine some aspects of the life cycle of A. longirostre in the laboratory, we performed infestations of larvae and nymphs on Serinus canaria (Common Canary - Passeriformes), Calomys callosus (Vesper mouse), Sphiggurus villosus (Brazilian porcupine), and Gallus gallus (chicks - no Passeriformes); this later host species only for larvae. While the overall recovery rates of engorged larvae and nymphs were low (at most 11.1%), the highest rates were for ticks that had fed on S. canaria (Passerifomes). This result is supported by field data, which indicate Passeriformes as preferable hosts for larvae and nymphs of A. longirostre. Interestingly, the suitability of the porcupine S. villosus as host for larvae and nymphs was statistically similar to S. canaria, although the recovery rates on the later host species were slightly higher. The Cricetidae mouse C. callosus displayed the lowest recovery rates (0–0.5%) of engorged ticks, indicating that mice might not be suitable hosts for A. longirostre under natural conditions. We also report three adult females of A. longirostre that were collected from two Bristle-spined porcupine Chaetomys subspinosus. Curiously, each of the three ticks was attached to the median third of a spine of the porcupines. The hypostome was surrounded by a cement-like structure at the spine external surface, but did not break through the external surface of the spine. Biological explanations for this behavior are discussed.

Domestic canaries (Serinus canaria forma domestica) are susceptible to low pathogenic avian influenza virus infections

ABSTRACTAvian influenza viruses have been isolated from many bird species; however, little is known about the susceptibility of pet birds to low pathogenic avian influenza (LPAI) viruses. To address this research gap, domestic canaries (Serinus canaria forma domestica) were experimentally infected with H5 and H7 LPAI viruses to determine susceptibility and to evaluate samples for diagnostic purposes. Clinical evidence of infection (e.g. ruffled plumage and apathy) and mortality were noted for the canaries inoculated with chicken-adapted LPAI viruses. Real-time reverse transcription-polymerase chain reaction (RRT-PCR) demonstrated higher viral RNA levels in buccal compared to faecal samples. No clinical signs or mortality were observed in canaries inoculated with LPAI virus originating from wild birds; however, the canaries in this group did have evidence of viral RNA in buccal and faecal samples. Overall, this study showed that domestic canaries are susceptible to LPAI virus infections and that they can shed large amounts of viral RNA, primarily through the respiratory route. Thus, buccal swabs might be better samples than faeces for efficient detection of some LPAI virus infections in these birds. Although canaries have not been identified as a significant reservoir for LPAI viruses, they may be infected by LPAI viruses. Thus, the importance of the control of domestic canaries for detection of LPAI viruses should not be underestimated, especially in the contexts of international commercial exchange and outbreaks.RESEARCH HIGHLIGHTSCanaries are susceptible to infection with H5/H7 LPAI viruses.Canaries inoculated with LPAI viruses excrete large amounts of viral RNA.Buccal swabs may be appropriate specimens for AI virus detection in canaries.The control of canaries for LPAI virus detection should not be overlooked.

Characterization of Plasmodium relictum, a cosmopolitan agent of avian malaria

BackgroundMicroscopic research has shown that Plasmodium relictum is the most common agent of avian malaria. Recent molecular studies confirmed this conclusion and identified several mtDNA lineages, suggesting the existence of significant intra-species genetic variation or cryptic speciation. Most identified lineages have a broad range of hosts and geographical distribution. Here, a rare new lineage of P. relictum was reported and information about biological characters of different lineages of this pathogen was reviewed, suggesting issues for future research.MethodsThe new lineage pPHCOL01 was detected in Common chiffchaff Phylloscopus collybita, and the parasite was passaged in domestic canaries Serinus canaria. Organs of infected birds were examined using histology and chromogenic in situ hybridization methods. Culex quinquefasciatus mosquitoes, Zebra finch Taeniopygia guttata, Budgerigar Melopsittacus undulatus and European goldfinch Carduelis carduelis were exposed experimentally. Both Bayesian and Maximum Likelihood analyses identified the same phylogenetic relationships among different, closely-related lineages pSGS1, pGRW4, pGRW11, pLZFUS01, pPHCOL01 of P. relictum. Morphology of their blood stages was compared using fixed and stained blood smears, and biological properties of these parasites were reviewed.ResultsCommon canary and European goldfinch were susceptible to the parasite pPHCOL01, and had markedly variable individual prepatent periods and light transient parasitaemia. Exo-erythrocytic and sporogonic stages were not seen. The Zebra finch and Budgerigar were resistant. Neither blood stages nor vector stages of all examined P. relictum lineages can be distinguished morphologically.ConclusionWithin the huge spectrum of vertebrate hosts, mosquito vectors, and ecological conditions, different lineages of P. relictum exhibit indistinguishable, markedly variable morphological forms. Parasites of same lineages often develop differently in different bird species. Even more, the variation of biological properties (parasitaemia dynamics, blood pathology, prepatent period) in different isolates of the same lineage might be greater than the variation in different lineages during development in the same species of birds, indicating negligible taxonomic value of such features. Available lineage information is excellent for parasite diagnostics, but is limited in predictions about relationships in certain host-parasite associations. A combination of experiments, field observations, microscopic and molecular diagnostics is essential for understanding the role of different P. relictum lineages in bird health.

Effects of food limitation on the intensity of blue‐green and brown eggshell coloration: an experimental study with the canary

Variation in blue‐green and brown coloration of avian eggshells could be affected by several factors, including environmental nutritional constraints. Better availability of nutrients could influence the synthesis and deposition of pigments into the eggshell, so we may expect a link between the food availability during egg formation, the body condition of the female and intensity of eggshell coloration. This hypothesis has received mixed support so far: in some bird species a positive correlation between female body condition and eggshell blue‐green coloration could be demonstrated, but other studies failed to find a significant link. In this study, we experimentally limited the food availability for domestic canaries Serinus canaria prior to and during egg laying, and examined its effects on the biliverdin‐ and protoporphyrin‐based eggshell coloration. Treatment had no significant effect on eggshell blue‐green chroma and biliverdin concentration. However, we found a significant positive relationship between female body condition and eggshell background blue‐green chroma in the control group, but not in the food restricted group. Females possibly experiencing a decline in antioxidant capacity due to food limitation may not be able to produce a blue‐green eggshell colour intensity reliably indicating their body condition. Furthermore, food‐restricted canary females laid eggs with significantly higher eggshell brown chroma, spot intensity, and protoporphyrin concentration. Therefore, our results suggest that limitation in actual nutrient availability increases deposition of protoporphyrin into the eggshell, and it may also modify the association between female body condition and intensity of blue‐green eggshell coloration.

Molecular characterization and distribution of Plasmodium matutinum, a common avian malaria parasite.

Species of Plasmodium (Plasmodiidae, Haemosporida) are widespread and cause malaria, which can be severe in avian hosts. Molecular markers are essential to detect and identify parasites, but still absent for many avian malaria and related haemosporidian species. Here, we provide first molecular characterization of Plasmodium matutinum, a common agent of avian malaria. This parasite was isolated from a naturally infected thrush nightingale Luscinia luscinia (Muscicapidae). Fragments of mitochondrial, apicoplast and nuclear genomes were obtained. Domestic canaries Serinus canaria were susceptible after inoculation of infected blood, and the long-lasting light parasitemia developed in two exposed birds. Clinical signs of illness were not reported. Illustrations of blood stages of P. matutinum (pLINN1) are given, and phylogenetic analysis identified the closely related avian Plasmodium species. The phylogeny based on partial cytochrome b (cyt b) sequences suggests that this parasite is most closely related to Plasmodium tejerai (cyt b lineage pSPMAG01), a common malaria parasite of American birds. Both these parasites belong to subgenus Haemamoeba, and their blood stages are similar morphologically, particularly due to marked vacuolization of the cytoplasm in growing erythrocytic meronts. Molecular data show that transmission of P. matutinum (pLINN1) occurs broadly in the Holarctic, and the parasite likely is of cosmopolitan distribution. Passeriform birds and Culex mosquitoes are common hosts. This study provides first molecular markers for detection of P. matutinum.