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We isolated highly pathogenic avian influenza (HPAI) H5N5 and H5N1 viruses from crows in Hokkaido, Japan, during winter 2023-24. They shared genetic similarity with HPAI H5N5 viruses from northern Europe but differed from those in Asia. Continuous monitoring and rapid information sharing between countries are needed to prevent HPAI virus transmission.
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It was recently found that not only tool-specialized New Caledonian crows, but also Goffin cockatoos can manufacture physical objects in accordance with a mental template. That is, they can emulate features of existing objects when they manufacture new items. Both species spontaneously ripped pieces of card into large strips if they had previously learned that a large template was rewarded, and small strips when they previously learned that a small template was rewarded. Among New Caledonian crows, this cognitive ability was suggested as a potential mechanism underlying the transmission of natural tool designs. Here, we tested for the same ability in another non-specialised tool user-Hooded crows (Corvus cornix). Crows were exposed to pre-made template objects, varying first in colour and then in size, and were rewarded only if they chose pre-made objects that matched the template. In subsequent tests, birds were given the opportunity to manufacture versions of these objects. All three crows ripped paper pieces from the same colour material as the rewarded template, and, crucially, also manufactured objects that were more similar in size to previously rewarded, than unrewarded, templates, despite the birds being rewarded at random in both tests. Therefore, we found the ability to manufacture physical objects relative to a mental template in yet another bird species not specialized in using or making foraging tools in the wild, but with a high level of brain and cognitive development.
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Corvos , Comportamento de Utilização de Ferramentas , Animais , Feminino , Masculino , Recompensa , CogniçãoRESUMO
The present study was aimed to investigate the role of cannibalism in transmission of H5N1 avian influenza virus to house crows (Corvus splendens). Four crows were intranasally inoculated with 108.0 EID50 (A/crow/India/01CA249/2021) H5N1 highly pathogenic avian influenza (HPAI) virus and were observed for 14 days for any overt signs of illness. Two of the infected crows showed signs of wing paralysis, incoordination, and torticollis. For cannibalism experiment, two crows showing clinical signs were euthanized on 14th day post-infection (dpi) and were kept in the isolator and four naïve healthy crows were introduced along with the euthanized crows. The viscera from the infected carcasses were eaten by all the four crows. Oropharyngeal and cloacal swabs were collected up to 14 days to assess virus excretion. All four crows showed clinical signs viz., dullness, reluctance to move with ruffled feathers on 6th day post cannibalism along with neurological signs including incoordination and paralysis of the wings. All the crows gradually recovered after showing clinical signs and were euthanized on 21st day of observation period. Virus excretion was observed from 3rd to 11th day post cannibalism through both oropharyngeal and cloacal routes with maximum shedding through oropharyngeal route. The virus was isolated from lungs and trachea of one the infected crows at 21st day after euthanasia. All the four crows seroconverted against H5N1 virus infection at 14th day post cannibalism. Our study confirms the transmission of H5N1 virus in crows through cannibalism and highlights how H5N1 virus might circulate in a crow colony once they become infected.
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Corvos , Virus da Influenza A Subtipo H5N1 , Vírus da Influenza A , Influenza Aviária , Animais , Paralisia , Ingestão de AlimentosRESUMO
Recursive sequence generation (i.e., the ability to transfer recursive patterns to novel items) was recently reported in crows (Liao et al., 2022, Science Advances, 8[44], eabq3356). Here, we argue that although the reported data are certainly compatible with the recursion hypothesis, they can also be explained by other, much simpler mechanisms of associative learning.
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Corvos , Aprendizagem , AnimaisRESUMO
Contrasting findings made it unclear what cognitive processes New Caledonian crows use to procure suitable tools to solve tool tasks. Most previous studies suggested that their tool procurement is achieved by either trial and error or a simple heuristic. The latter provides a fast and cognitively efficient method for stable, routinized behaviour based on past experience with little or no deliberate decision-making. However, early papers by Chappell and Kacelnik reported that two New Caledonian crows procured tools after closely assessing the tool characteristics required for the task, thus using deliberate decision-making, or a 'customized strategy'. Here, I tested eight New Caledonian crows to determine their default behaviour in basic tool procurement tasks as a check on whether or not they use customized strategies. I used two rigorous experiments closely based on Chappell and Kacelnik's experiments. The crows did not use a customized strategy in either experiment, but their behaviour was clearly consistent with tool procurement predominantly guided by a familiarity heuristic. I discuss potential methodological issues that may have led to different conclusions in Chappell and Kacelnik's studies. Heuristic-guided, routinized behaviour in tool procurement has potential implications for understanding how standardization occurs in the early evolution of complex tool manufacture, both in New Caledonian crows and early humans.
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Corvos , Comportamento de Utilização de Ferramentas , Animais , Compreensão , HeurísticaRESUMO
When one considers the avalanche of new indications and uses for botulinum toxins, it is truly surprising that this has all happened in such a short time. And the safety and dependability of these products are profound, when used appropriately. There is still much to be discovered about the potential of this agent when you contemplate the profound non-cosmetic benefits reported by clinicians and scientists from around the world. The mechanism of action has been studied in depth, and yet the benefits appreciated by people with chronic migraine or major depressive disorder, for instance, are unlikely to be explained by our current mechanistic understanding. Given that these toxins control acetylcholine at the motor end plates, and given that acetylcholine is central to practically every cell in the body, it will not be surprising to find that botulinum toxin researchers will be enjoying many decades of fruitful studies. The advent of the non-surgical aesthetic physician has helped push the clinical utilization of botulinum toxins well beyond its original adoption by oculoplastic surgeons in their patients with blepharospasm. We can expect that the next edition of this book to have a dozen or more new indications which will surprise us all.
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Toxinas Botulínicas Tipo A , Técnicas Cosméticas , Transtorno Depressivo Maior , Hiperidrose , Envelhecimento da Pele , Estética , Humanos , Hiperidrose/tratamento farmacológicoRESUMO
The ability to plan for future events is one of the defining features of human intelligence. Whether non-human animals can plan for specific future situations remains contentious: despite a sustained research effort over the last two decades, there is still no consensus on this question. Here, we show that New Caledonian crows can use tools to plan for specific future events. Crows learned a temporal sequence where they were (a) shown a baited apparatus, (b) 5 min later given a choice of five objects and (c) 10 min later given access to the apparatus. At test, these crows were presented with one of two tool-apparatus combinations. For each combination, the crows chose the right tool for the right future task, while ignoring previously useful tools and a low-value food item. This study establishes that planning for specific future tool use can evolve via convergent evolution, given that corvids and humans shared a common ancestor over 300 million years ago, and offers a route to mapping the planning capacities of animals.
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Corvos , Comportamento de Utilização de Ferramentas , Animais , Nova CaledôniaRESUMO
Gruber et al. (Current Biology, 29, 686-692, 2019) report that New Caledonian crows engage in mental representation to solve a problem involving a tool. Although the crows' success is impressive, an associative account of their behavior calls into question the extent to which the data reflect representation of future states.
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Corvos , Comportamento de Utilização de Ferramentas , Animais , AprendizagemRESUMO
We previously demonstrated that chimpanzees, like humans, showed better accuracy and faster response time in discriminating visual patterns when the patterns were presented in redundant and uninformative contexts than when they were presented alone. In the present study, we examined the effect of redundant context on pattern discrimination in pigeons (Columba livia) and large-billed crows (Corvus macrorhynchos) using the same task and stimuli as those used in our previous study on chimpanzees. Birds were trained to search for an odd target among homogenous distractors. Each stimulus was presented in one of three ways: (1) alone, (2) with identical context that resulted in emergent configuration to chimpanzees (congruent context), or (3) with identical context that did not result in emergent configuration to chimpanzees (incongruent context). In contrast to the facilitative effect of congruent contexts we previously reported in chimpanzees, the same contexts disrupted target localization performance in both pigeons and crows. These results imply that birds, unlike chimpanzees, do not perceive emergent configurations.
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Columbidae , Corvos , Animais , Aprendizagem por Discriminação , Humanos , Pan troglodytes , Tempo de ReaçãoRESUMO
BACKGROUND: Although genomic DNA isolation using the Chelex 100 resin is rapid and inexpensive, the DNA obtained by this method has a low concentration in solution and contains suspended impurities. The presence of debris in the DNA solution may result in degradation of DNA on long term storage and inhibition of the polymerase chain reaction. In order to remove impurities and concentrate the DNA in solution, we have introduced modifications in the existing DNA isolation protocol using Chelex-100. We used ammonium acetate to precipitate proteins and a sodium acetate- isopropanol mixture to pellet out DNA which was washed with ethanol. RESULTS: A pure DNA pellet that can be dissolved in water or Tris-EDTA buffer and stored for a long time at - 80 °C was obtained. We also observed a 20-fold change in the DNA concentration following precipitation and re-dissolution. CONCLUSION: Our method is different from other extraction methods since it uses non-toxic, easily available and inexpensive reagents as well as minimal amounts of blood or tissue samples for the DNA extraction process. Besides its use in sex determination and genotyping in lab animals as described in this paper, it may also have applications in forensic science and diagnostics such as the easy detection of pathogenic DNA in blood.
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Campylobacter spp. are major causes of gastroenteritis worldwide. The virulence potential of Campylobacter shed in crow feces obtained from a roost area in Bothell, Washington, was studied and compared with that from isolates from other parts of Washington and from a different crow species 7,000 miles away in Kolkata, India. Campylobacter organisms were isolated from 61% and 69% of the fecal samples obtained from Washington and Kolkata, respectively, and were confirmed to be C. jejuni The cytolethal distending toxin (CDT) gene cluster from these isolates revealed a truncated sequence of approximately 1,350 bp. Sequencing of the gene cluster revealed two types of mutations: a 668-bp deletion across cdtA and cdtB and a 51-bp deletion within cdtB Some strains had additional 20-bp deletions in cdtB In either case, a functional toxin is not expected; a functional toxin is produced by the expression of three tandem genes, cdtA, cdtB, and cdtC Reverse transcriptase PCR with total RNA extracted from the isolates showed no expression of cdtB A toxin assay performed with these isolates on HeLa cells failed to show cytotoxic effects on the cells. However, the isolates were able to colonize the chicken ceca for a period of at least 4 weeks, similar to that of a clinical isolate. Other virulence gene markers, flagellin A and CadF, were present in 100% of the isolates. Our study suggests that crows carry the bacterium C. jejuni but with a dysfunctional toxin protein that is expected to drastically reduce its potential to cause diarrhea.IMPORTANCE Campylobacters are a major cause of gastroenteritis in humans. Since outbreaks have most often been correlated with poultry or unpasteurized dairy products, contact with farm animals, or contaminated water, historically, the majority of the studies have been with campylobacter isolates from poultry, domestic animals, and human patients. However, the bacterium has a broad host range that includes birds. These reservoirs need to be investigated, because the identification of the source and a determination of the transmission routes for a pathogen are important for the development of evidence-based disease control programs. In this study, two species of the human-commensal crow, from two different geographical regions separated by 7,000 miles of land and water, have been examined for their ability to cause disease by shedding campylobacters. Our results show that the crow may not play a significant role in campylobacteriosis, because the campylobacter organisms they shed produce a nonfunctional toxin.
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Sequência de Bases , Doenças das Aves/microbiologia , Infecções por Campylobacter/veterinária , Campylobacter jejuni/fisiologia , Campylobacter jejuni/patogenicidade , Corvos , Deleção de Sequência , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Infecções por Campylobacter/microbiologia , Campylobacter jejuni/genética , Trato Gastrointestinal/microbiologia , Genes Bacterianos , Índia , Família Multigênica , Mutação , Virulência , WashingtonRESUMO
The classic Aesop's fable, Crow and the Pitcher, has inspired a major line of research in comparative cognition. Over the past several years, five articles (over 32 experiments) have examined the ability of corvids (e.g., rooks, crows, and jays) to complete lab-based analogs of this fable, by requiring them to drop stones and other objects into tubes of water to retrieve a floating worm (Bird and Emery in Curr Biol 19:1-5, 2009b; Cheke et al. in Anim Cogn 14:441-455, 2011; Jelbert et al. in PLoS One 3:e92895, 2014; Logan et al. in PLoS One 7:e103049, 2014; Taylor et al. in Gray R D 12:e26887, 2011). These researchers have stressed the unique potential of this paradigm for understanding causal reasoning in corvids. Ghirlanda and Lind (Anim Behav 123:239-247, 2017) re-evaluated trial-level data from these studies and concluded that initial preferences for functional objects, combined with trial-and-error learning, may account for subjects' performance on key variants of the paradigm. In the present paper, we use meta-analytic techniques to provide more precise information about the rate and mode of learning that occurs within and across tasks. Within tasks, subjects learned from successful (but not unsuccessful) actions, indicating that higher-order reasoning about phenomena such as mass, volume, and displacement is unlikely to be involved. Furthermore, subjects did not transfer information learned in one task to subsequent tasks, suggesting that corvids do not engage with these tasks as variants of the same problem (i.e., how to generate water displacement to retrieve a floating worm). Our methodological analysis and empirical findings raise the question: Can Aesop's fable studies distinguish between trial-and-error learning and/or higher-order causal reasoning? We conclude they cannot.
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Corvos/fisiologia , Aprendizagem , Resolução de Problemas , Animais , Cognição , Comportamento de Utilização de FerramentasRESUMO
Large-scale, comparative cognition studies are set to revolutionize the way we investigate and understand the evolution of intelligence. However, the conclusions reached by such work have a key limitation: the cognitive tests themselves. If factors other than cognition can systematically affect the performance of a subset of animals on these tests, we risk drawing the wrong conclusions about how intelligence evolves. Here, we examined whether this is the case for the A-not-B task, recently used by MacLean and co-workers to study self-control among 36 different species. Non-primates performed poorly on this task; possibly because they have difficulty tracking the movements of a human demonstrator, and not because they lack self-control. To test this, we assessed the performance of New Caledonian crows on the A-not-B task before and after two types of training. New Caledonian crows trained to track rewards moved by a human demonstrator were more likely to pass the A-not-B test than birds trained on an unrelated choice task involving inhibitory control. Our findings demonstrate that overlooked task demands can affect performance on a cognitive task, and so bring into question MacLean's conclusion that absolute brain size best predicts self-control.
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Encéfalo/anatomia & histologia , Corvos/fisiologia , Comportamento Exploratório , Autocontrole , Animais , Comportamento de Escolha , Feminino , Masculino , RecompensaRESUMO
BACKGROUND: Perioral wrinkling is commonly reported among older adults, but its objective evaluation and causes remain poorly understood. OBJECTIVE: We sought to develop a photonumeric scale for perioral wrinkling and to elucidate contributory lifestyle factors. METHODS: In this cross-sectional study, we recruited participants for facial photographs and a survey. A gender-specific photonumeric scale for perioral wrinkling was developed and used by 3 graders to evaluate participant photographs. Scores and survey responses were used to create a multiple regression model to predict perioral wrinkling. RESULTS: In all, 143 participants aged 21 to 91 years were enrolled. Intraclass correlation coefficient values for interrater and intrarater reliability were high (>0.8) across 2 trials and 3 graders. A multiple regression model for prediction of perioral wrinkling severity included age, gender, and years of smoking as variables. LIMITATIONS: The study was limited by sample size and a predominantly Caucasian study population. CONCLUSION: We created a photonumeric scale that accounts for gender differences in perioral wrinkling and highlighted contributory variables to photoaging in this anatomical location.
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Envelhecimento/fisiologia , Estilo de Vida , Fotografação , Envelhecimento da Pele/fisiologia , Fumar/efeitos adversos , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Intervalos de Confiança , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Boca , Análise Multivariada , Análise de Regressão , Fatores de Risco , Adulto JovemRESUMO
INTRODUCTION: Crows' feet wrinkles are caused by the action of the orbicularis oculi muscle on overlying skin. Treatment options range from botulinum toxin to a multitude of surgical methods. We first described our technique in 2003 and refined it in 2006. We highlight the evolution of our technique and look at our results to assess the effectiveness of our technique. OBJECTIVE: The aim of this article is to show our experience of 13 years in 134 patients with our technique of orbicularis oculi myectomy. METHODS: From September 2000 to July 2013, we operated on 134 patients with an age range of 28-77 years. Of these patients, 104 had myectomies via lifting and 22 via a blepharoplasty approach. Five patients had myectomies for treatment of blepharospasm and a further three patients to restore symmetry in facial palsy. An evaluation of the results was performed by two medical students. RESULTS: Our results showed reduction of the wrinkles in all cases. For the statistical analysis the Wilcoxon test was performed. The p value was less than 0.001 showing a significant reduction of crows' feet wrinkles in both sides when the orbicularis myectomy was performed, via blepharoplasty or lifting. For myectomy performed for blepharospasm or facial palsy, the statistical analysis was not done due to the low numbers. CONCLUSION: In the appropriate patient, orbicularis oculi myectomy is an effective and long-term treatment for crows' feet wrinkles with a low risk of complications and high patient satisfaction. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .
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Blefarospasmo/cirurgia , Músculos Faciais/cirurgia , Músculos Oculomotores/cirurgia , Ritidoplastia/métodos , Adulto , Idoso , Blefarospasmo/tratamento farmacológico , Toxinas Botulínicas/administração & dosagem , Estudos de Coortes , Estética , Músculos Faciais/efeitos dos fármacos , Humanos , Pessoa de Meia-Idade , Músculos Oculomotores/efeitos dos fármacos , Estudos Retrospectivos , Medição de Risco , Envelhecimento da Pele , Cirurgia Plástica/métodos , Resultado do TratamentoRESUMO
Humans are capable of simply observing a correlation between cause and effect, and then producing a novel behavioural pattern in order to recreate the same outcome. However, it is unclear how the ability to create such causal interventions evolved. Here, we show that while 24-month-old children can produce an effective, novel action after observing a correlation, tool-making New Caledonian crows cannot. These results suggest that complex tool behaviours are not sufficient for the evolution of this ability, and that causal interventions can be cognitively and evolutionarily disassociated from other types of causal understanding.
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Evolução Biológica , Cognição , Corvos/fisiologia , Aprendizagem , Comportamento de Utilização de Ferramentas , Animais , Pré-Escolar , Condicionamento Operante , Feminino , Humanos , Lactente , Masculino , Nova CaledôniaRESUMO
Wild birds could be a reservoir of medically relevant microorganisms, particularly multidrug-resistant Enterococcus spp. Resistant bacteria's epidemiology and transmission between animals and humans has grown, and their zoonotic potential cannot be ignored. This is the first study to evaluate the status of vancomycin resistant enterococci (VRE) in various wild bird species using meta-analysis and a systematic review. In this study, the pooled prevalence was obtained by analyzing data from published articles on the occurrence of VRE in wild bird species. It's unclear how the antibiotic resistance gene transfer cycle affects wild birds. Google Scholar and PubMed were used to conduct the research. The data and study methodology was assessed and extracted by two reviewers independently, with a third reviewing the results. Heterogeneity between study and publication bias were analyzed using the random effect model. Thirty-eight studies were included in the meta-analysis. 382 out of the 4144 isolates tested, were VRE. The pooled prevalence of VRE among wild birds was estimated at 11.0% (95% CI; 6.9 -17.2%; I2 = 93.204%; P < 0.001). There was high variability between study (t2 = 2.156; heterogeneity I2 = 93.204% with chi-square (Q) = 544.413, degrees of freedom (df) = 37, and P < 0.001). Egger's test verified the funnel plot's bias, while result from the leave-one-out forest plot had no effect on the pooled prevalence.
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Animais Selvagens , Aves , Infecções por Bactérias Gram-Positivas , Enterococos Resistentes à Vancomicina , Animais , Animais Selvagens/microbiologia , Aves/microbiologia , Infecções por Bactérias Gram-Positivas/epidemiologia , Infecções por Bactérias Gram-Positivas/veterinária , Infecções por Bactérias Gram-Positivas/microbiologia , Prevalência , Enterococos Resistentes à Vancomicina/isolamento & purificaçãoRESUMO
Characterizing the processes underlying reproductive isolation between diverging lineages is central to understanding speciation. Here, we present RIDGE-Reproductive Isolation Detection using Genomic polymorphisms-a tool tailored for quantifying gene flow barrier proportion and identifying the relevant genomic regions. RIDGE relies on an Approximate Bayesian Computation with a model-averaging approach to accommodate diverse scenarios of lineage divergence. It captures heterogeneity in effective migration rate along the genome while accounting for variation in linked selection and recombination. The barrier detection test relies on numerous summary statistics to compute a Bayes factor, offering a robust statistical framework that facilitates cross-species comparisons. Simulations revealed RIDGE's efficiency in capturing signals of ongoing migration. Model averaging proved particularly valuable in scenarios of high model uncertainty where no migration or migration homogeneity can be wrongly assumed, typically for recent divergence times <0.1 2Ne generations. Applying RIDGE to four published crow data sets, we first validated our tool by identifying a well-known large genomic region associated with mate choice patterns. Second, while we identified a significant overlap of outlier loci using RIDGE and traditional genomic scans, our results suggest that a substantial portion of previously identified outliers are likely false positives. Outlier detection relies on allele differentiation, relative measures of divergence and the count of shared polymorphisms and fixed differences. Our analyses also highlight the value of incorporating multiple summary statistics including our newly developed outlier ones that can be useful in challenging detection conditions.
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Fluxo Gênico , Especiação Genética , Teorema de Bayes , Genômica , GenomaRESUMO
Little is known about the prevalence of antimicrobial-resistant bacteria and pathogenic Escherichia coli in crows (carrion and jungle crows). We studied the phylogeny, virulence and antimicrobial resistance gene profiles of crow E. coli isolates to investigate their zoonotic potential and molecular epidemiology. During the winter of 2021-2022, 34 putative E. coli isolates were recovered from 27 of the 65 fresh fecal samples collected in urban areas. Three strains of the B1-O88:H8-ST446-fimH54 lineage, classified as extraintestinal pathogenic E. coli (ExPEC) and necrotoxigenic E. coli type 2, were colistin-resistant and harbored mcr-1.1-carrying IncI2 plasmids. The blaCTX-M-55 was identified in a multidrug-resistant B1-O non-typeable:H23-ST224-fimH39 strain. In phylogroup B2, two lineages of O6:H1-ST73-fimH30 and O6:H5-ST83-fimH21 were classified as ExPEC, uropathogenic E. coli, and necrotoxigenic E. coli type 1 (O6:H5-ST83-fimH21), and contained several virulence genes associated with avian pathogenic E. coli. Noteworthy is that three isolates, identified as E. coli by MALDI-TOF MS, were confirmed to be two Escherichia marmotae (cryptic clade V) and one Escherichia ruysiae (cryptic clade III) based on ANI and dDDH analyses. Our results provide the first evidence of these new species in crows. E. marmotae and E. ruysiae isolates in this study were classified as ExPEC and contained the enteroaggregative E. coli heat-stable toxin 1 gene. In addition, these two E. marmotae isolates displayed a close genetic relationship with human isolates associated with septicemia. This study provides the first insights into the prevalence and zoonotic significance of Escherichia spp. in urban crows in Japan, posing a significant risk for their transmission to humans.
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Corvos , Escherichia coli , Animais , Humanos , Escherichia coli/genética , Antibacterianos/farmacologia , Japão/epidemiologia , Farmacorresistência Bacteriana/genéticaRESUMO
Corvids (crows, magpies, jays) live in a close association with humans, and therefore knowledge about their population status and changes will be an essential part of monitoring the quality of urban environments. Wintering bird populations can track habitat and climate changes more rapidly than breeding populations. We conducted a long-term (1991-2020) winter census of corvid species in 31 human settlements along a 920 km latitudinal gradient in Finland. We observed a total of five corvid species: the Eurasian Magpie (occurring in 114 surveys out of 122; total abundance 990 ind.), the Hooded Crow (in 96 surveys; 666 ind.), the Eurasian Jackdaw (in 51 surveys; 808 ind.), the Eurasian Jay (in 5 surveys; 6 ind.) and the Rook (in 1 survey; 1 ind.). Only the numbers of the Eurasian Jackdaw differed between the study winters, being greater at the end of the study period (2019/2020) than during the earlier winters (1991/1992 and 1999/2000). The average growth rate (λ) of the Eurasian Jackdaw increased during the study period, whereas no changes were observed in the cases of the Hooded Crow or the Eurasian Magpie. The growth rate of the Eurasian Jackdaw was greater than that observed in the Finnish bird-monitoring work, probably because our data came only from the core area of each human settlement. Even though the number of buildings and their cover increased in the study plots, and the winter temperature differed between winters, the average growth rate (λ) of corvid species did not significantly correlate with these variables. These results suggest that urban settlements are stable wintering environments for the generalist corvids. The between-species interactions were all positive, but non-significant. Despite the total number of winter-feeding sites being greater during the winter of 1991/1992 than during the winter of 2019/2020, the changes in the numbers of feeding stations did not correlate with the growth rates of any corvid species. We assume that the Eurasian Jackdaw has benefitted from the decreased persecution, and probably also from large-scale climate warming that our study design was unable to take in to account. Our results indicated that wintering corvid populations succeed well in the human settlements in Finland. We recommend conducting long-term corvid research, also during breeding season, to understand more detailed causes of the population changes of corvids along an urban gradient. Without year-round long-term monitoring data, the conservation and management recommendations related to the corvid species in urban habitats may be misleading.