Free-living Wild Birds Research Articles

Morbidity of Rescued Wild Birds by Admission Causes in the Republic of Korea.

Insufficient reports are available on what clinical and pathological conditions are observed in rescued free-living wild birds. This study investigated recent diagnoses of admitted wild birds based on admission causes in a southwestern area of South Korea over the past 2 years. A retrospective study was conducted on 1464 birds rescued from 2019 to February 2021. Overall, 12 admission subcategories were classified, and the diagnoses identified for each cause were analyzed. The three most frequently observed categories, general, integumentary, and musculoskeletal, each accounted for 20% of the total diagnoses. Trauma accounted for 71.4% of all diagnoses, and 81.5% featured inflammatory conditions, primarily due to trauma or infection. The proportion of birds that presented inflammatory conditions was much greater than the proportion of birds that were admitted due to trauma-related causes. This was because inflammatory diseases were identified at a high frequency, even from nontraumatic admission causes, and inflammatory conditions were not easily revealed. Suspecting an inflammatory condition in most rescued birds is advisable.

First identification and molecular subtyping of Blastocystis in free-living wild birds from urban Xinxiang, China.

Blastocystis is a common enteric protist infecting humans, domestic animals, and wildlife worldwide. However, data on the prevalence and subtype diversity of Blastocystis in free-living wild birds in urban districts are rare. In this study, a total of 138 fresh fecal samples from free-living wild birds were collected from three universities and three communities in Xinxiang, China, to explore the infection rate, Blastocystis subtypes present and zoonotic potential of this protist. Blastocystis presence was determined with nested-PCR amplification based on the partial small ribosomal subunit (SSU rRNA) gene. Presence was detected from one community (Wupu) at an overall rate of 1.5% (2/136). Further DNA sequencing and phylogenetic analyses identified two ruminant-associated subtypes, ST10 (n = 1) and ST24 (n = 1), implying a cross-species transmission of Blastocystis from ruminants. This is the first report on the infection of ST10 and ST24 in free-living wild birds in an urban area in China. As potentially zoonotic subtypes, the occurrence of ST10 and ST24 suggests that these free-living birds could play a role in spreading Blastocystis to humans in Xinxiang.

Identification and antimicrobial resistance profile in bacteria isolated from Brown Aracari (Pteroglossus castanotis australis) – case report

Studies involving Brown Aracari (Pteroglossus castanotis australis) are scarce due to the difficulty in studying free-living species without human interference, the works available in the literature are generally on animals in captivity. Free-living wild birds can be considered reservoirs of microorganisms carrying bacterial multi-resistance, which can become a serious problem in terms of unique health. The aim of this study was to identify the microorganisms and evaluate the profile of resistance to conventional antimicrobials in a free-living Brown Aracari (P. c. australis) in a border region in the state of Paraná, Brazil.

In vitro and in vivo susceptibility to sulfadiazine and pyrimethamine of Toxoplasma gondii strains isolated from Brazilian free wild birds

Little is known about the existence of drug-resistant Toxoplasma gondii strains and their possible impact on clinic outcomes. To expand our knowledge about the existence of natural variations on drug susceptibility of T. gondii strains in Brazil, we evaluated the in vitro and in vivo susceptibility to sulfadiazine (SDZ) and pyrimethamine (PYR) of three atypical strains (Wild2, Wild3, and Wild4) isolated from free-living wild birds. In vitro susceptibility assay showed that the three strains were equally susceptible to SDZ and PYR but variations in the susceptibility were observed to SDZ plus PYR treatment. Variations in the proliferation rates in vitro and spontaneous conversion to bradyzoites were also accessed for all strains. Wild2 showed a lower cystogenesis capacity compared to Wild3 and Wild4. The in vivo analysis showed that while Wild3 was highly susceptible to all SDZ and PYR doses, and their combination, Wild2 and Wild4 showed low susceptibility to the lower doses of SDZ or PYR. Interestingly, Wild2 presented low susceptibility to the higher doses of SDZ, PYR and their combination. Our results suggest that the variability in treatment response by T. gondii isolates could possibly be related not only to drug resistance but also to the strain cystogenesis capacity.

Molecular and epidemiological surveillance of Plasmodium spp. during a mortality event affecting Humboldt penguins (Spheniscus humboldti) at a zoo in the UK.

In 2017, a mortality event affected Humboldt penguins at Chester Zoo (UK), which coincided with the diagnosis of avian malaria (AM) in some birds. AM is found worldwide wherever a competent mosquito vector is present, but the disease is particularly severe in penguins and other species that originate from non-endemic regions. To better understand the role of AM and manage its threat to penguin collections, Plasmodium was surveyed through PCR at Chester Zoo in mosquitoes, penguins, and dead free-living wild birds during and around the mortality event. Additional sequences were obtained from penguin fatalities from four other UK zoological collections. All sequences were integrated into phylogenetic analyses to determine parasite species and lineages. In total, 753/6459 positive mosquitoes were recorded (11.7% prevalence), reaching a weekly peak of 30% prevalence in mid-summer. Among penguin fatalities at Chester Zoo, several penguins presented signs and lesions compatible with AM; nevertheless, exoerythrocytic meronts were identified in only one case and Plasmodium spp. was identified in 5/22 birds. Phylogenetic analysis revealed at least five parasite cytb lineages of three Plasmodium species (P. matutinum, P. relictum and P. vaughani) circulating in mosquitoes at Chester Zoo; however, infections in free-living wild birds and penguins were only from P. matutinum. Plasmodium matutinum was confirmed as the cause of death of one penguin and was highly suspected to be the cause of death of another three. The lineage LINN1 was associated with 4/5 penguin infections. AM had a key role in the penguin multicausal mortality event. Understanding the risk of AM to penguin collections at Chester Zoo and elsewhere requires long-term surveillance to examine the association between Plasmodium infection and penguin mortality and the variability in parasite virulence. Surveillance of Plasmodium spp. in mosquitoes and local birds provides information about the parasite's transmission cycle locally, and could warn about infection risks to species of interest, which is essential for efficient disease control and prevention.

Gastrointestinal parasites in captive and free-living wild birds in Goiania Zoo.

Helminths are endoparasites that infect a variety of bird species. Endoparasite infections can cause severe diseases, including kill captive avian hosts and represents a problem to maintenance and conservation. The eggs and larval forms of these parasites are usually eliminated in the host feces. The main interest of this study is to report the occurrence of eggs and oocysts in feces from captive wild birds in Goiânia Zoo and free-living birds in its surroundings. The fecal samples were subjected to parasitological examination to identify the presence of helminths and to classify their eggs based on morphological characteristics. Eggs of nematode parasites (Positive/N) were identified as Ascaridia spp. in Brotogeris chiriri (2/2), Dromaius novaehollandiae (1/1) and Rhea americana (2/2); Ascarididae in Pavo cristatus nigripensis (1/1); Capillaria spp. in Ara chloropterus (1/1) and Penelope jacucaca (1/1); Capillaria plagiaticia in Anodorhynchus hyacinthinus (1/2) and Ara spp. (2/2); Capillaria venusta in Rhamphastus tucanus (1/2); and unidentified nematode eggs from Amazona amazonica (2/2). Eimeria spp. oocyst was founded in feces from A. hyacinthinus (1/2). Considering free-living birds, Diphyllobothrium spp. eggs were founded in Ardea alba (2/2) and Nycticorax nycticorax (2/3). Co-infection of Eustrongylides spp. was founded in A. alba (1/2). This is the first occurrence of: Ascaridia spp. parasitizing B. chiriri; and C. venusta parasitizing R. tucanus. In conclusion, the helminth eggs found in the abovementioned host bird species are consistent with those reported in the literature, and treatment and control protocols were based on their identification.

Infectious bursal disease virus in free-living wild birds: A systematic review and meta-analysis of its sero-viroprevalence on a global scale.

Infectious bursal disease virus (IBDV) is an economically important pathogen for poultry, whereas knowledge of its occurrence in non-poultry hosts is limited. The objective of this systematic review and meta-analysis is to summarize the up-to-date knowledge about the sero-viroprevalence of IBDV in wild birds on a global scale. A computerized literature research was performed on PubMed, Scopus, CAB Direct and Web of Science to find relevant publications, along with the screening of reference lists. Journal articles, book chapters, scientific correspondences, conference proceedings and short communications on IBDV virological and/or serological surveys in free-living wild birds published between 1970 and 2021 were considered as eligible. Among 184 studies found, 36 original contributions met the pre-established criteria. A random-effect model was applied to calculate pooled seroprevalence estimates with 95% confidence intervals, whereas the paucity of virological studies (n=6) only allowed a qualitative description of the data. The pooled seroprevalence was estimated to be 6% (95% CI: 3%-9%) and a high heterogeneity was detected (I2 =96%). Sub-group analyses were not performed due to the scarcity of available information about hypothetical moderators. With respect to virological studies, IBDV was detected in Anseriformes, Columbiformes, Galliformes, Passeriformes and Pelecaniformes and different strains related to poultry infection were isolated. Our estimates of serological data showed a moderate exposure of wild birds to IBDV. The susceptibility of different species to IBDV infection underlines their potential role in its epidemiology at least as carriers or spreaders. Indeed, the isolation of IBDV in healthy wild birds with a migratory attitude might contribute to a long-distance spread of the virus and to strain diversity. While a wild reservoir host could not be clearly identified, we believe our work provides useful insights for conducting future surveys which are needed to broaden our knowledge of IBDV occurrence in wild birds.

Wild Birds as Possible Source of Campylobacter jejuni

A variety of pathogens that are transmissible to humans or domestic animals, such as salmonella, shigella, and <i>Campylobacter jejuni</i>, can be found in free-living wild birds like the migratory birds that play an important role as long-distance vectors

A Review on the Prevalence of Poxvirus Disease in Free-Living and Captive Wild Birds

Avian pox is a widespread infection in birds caused by genus Avipoxvirus pathogens. It is a noteworthy, potentially lethal disease to wild and domestic hosts. It can produce two different conditions: cutaneous pox, and diphtheritic pox. Here, we carry out an exhaustive review of all cases of avian pox reported from wild birds to analyze the effect and distribution in different avian species. Avian poxvirus strains have been detected in at least 374 wild bird species, a 60% increase on a 1999 review on avian pox hosts. We also analyze epizootic cases and if this disease contributes to wild bird population declines. We frequently observe very high prevalence in wild birds in remote island groups, e.g., Hawaii, Galapagos, etc., representing a major risk for the conservation of their unique endemic avifauna. However, the difference in prevalence between islands and continents is not significant given the few available studies. Morbidity and mortality can also be very high in captive birds, due to high population densities. However, despite the importance of the disease, the current detection rate of new Avipoxvirus strains suggests that diversity is incomplete for this group, and more research is needed to clarify its real extent, particularly in wild birds.

Molecular Identification of Cryptosporidium spp. and Giardia spp. in Wild Birds in Southeastern Brazil

Introduction: The identification of Cryptosporidium spp., Giardia spp. and Enterocytozoon bieneusi in birds is relevant since these animals can act as disseminators of these parasites to humans through environmental contamination. The aim of this study was to determine the molecular occurrence of Cryptosporidium spp. and Giardia spp. in wild birds in southeastern Brazil and genetically characterize the isolates obtained. Methods: A total of 256 fecal samples were collected from 172 captive and 84 free-living wild birds. The DNA extracted was subjected to nested-PCR and semi-nested PCR analysis for amplification of fragments of the 18S rDNA and gdh genes of Cryptosporidium spp. and Giardia spp., respectively. Results: With respect to Cryptosporidium spp., the overall occurrence was 3.91%. Of samples from captive wild birds, six (3.49%) were positive: two waterfowl and four non-aquatic birds. Among the samples from free-living wild birds, four (4.76%) were positive, all non-aquatic birds. Regarding Giardia spp., the overall occurrence was 3.1%. Of samples from captive wild birds, four (2.32%) were positive, all waterfowl; of the samples from free-living wild birds, four (4.76%) were positive for the parasite, all non-aquatic birds. Conclusions: The presence of C. meleagridis and G. duodenalis assemblage B suggests that epidemiological studies involving wild birds and humans are needed to better understand the impact of avian cryptosporidiosis and giardiasis on avian health and their possible implications for public health.

Free-Living Wild Birds and Factors Influencing Their Survival in Captivity: A Synopsis

Free-Living Wild Birds and Factors Influencing Their Survival in Captivity: A Synopsis

Ecology and Neurobiology of Fear in Free-Living Wildlife

The ecology of fear concerns the population-, community-, and ecosystem-level consequences of the behavioral interactions between predators and prey, i.e., the aggregate impacts of individual responses to life-threatening events. We review new experiments demonstrating that fear itself is powerful enough to affect the population growth rate in free-living wild birds and mammals, and fear of large carnivores—or the human super predator—can cause trophic cascades affecting plant and invertebrate abundance. Life-threatening events like escaping a predator can have enduring, even lifelong, effects on the brain, and new interdisciplinary research on the neurobiology of fear in wild animals is both providing insights into post-traumatic stress (PTSD) and reinforcing the likely commonality of population- and community-level effects of fear in nature. Failing to consider fear thus risks dramatically underestimating the total impact predators can have on prey populations and the critical role predator-prey interactions can play in shaping ecosystems.

Potential reverse spillover of infectious bursal disease virus at the interface of commercial poultry and wild birds

Recently, multiple spillover events between domesticated poultry and wild birds have been reported for several avian viruses. This phenomenon highlights the importance of the livestock-wildlife interface in the possible emergence of novel viruses. The aim of the current study was to investigate the potential spillover and epidemiological links of infectious bursal disease virus (IBDV) between wild birds and domestic poultry. To this end, twenty-eight cloacal swabs were collected from four species of free-living Egyptian wild birds (i.e. mallard duck, bean goose, white-fronted goose and black-billed magpie). Genetic and phylogenetic analysis of three positive isolates revealed that the IBDV/USC-1/2019 strain clustered with previously reported very virulent IBDV (vvIBDV) Egyptian isolates. Interestingly, two other wild bird-origin isolates (i.e. IBDV/USC-2/2019 and IBDV/USC-3/2019) grouped with a vaccine strain that is being used in commercial poultry. In conclusion, our results revealed the molecular detection of vaccine and vvIBDV-like strains in Egyptian wild birds and highlighted the potential role of wild birds in IBDV epidemiology in disease-endemic regions.

Research Note: Detection of infectious bursal disease virus antibodies in free-living wild birds in Zaria, Nigeria

Infectious bursal disease virus (IBDV) is an immunosuppressive pathogen of poultry causing great economic losses to the poultry industry. In this study, the IBDV antibodies were detected in captured free-living wild birds in Zaria, Nigeria. One hundred and fifty free-living wild birds, comprising 30 birds each of 5 different species, were sampled over a period of 9 months. Blood samples were collected from each bird, and harvested sera were tested for IBDV antibodies using enzyme-linked immunosorbent assay. Results indicated IBDV seroprevalences in speckled pigeon (6.67%) and cattle egret (3.33%). In conclusion, the detection of IBDV antibodies in free-living wild birds in this study is indicative of previous natural exposure of these birds to the virus. These species of wild birds could therefore serve as carriers of these viruses and, consequently, transmit these viruses to chickens.

Genetic diversity of Toxoplasma gondii isolates obtained from free-living wild birds rescued in Southeastern Brazil.

Recent studies carried out in Brazil have shown that strains from the same Toxoplasma gondii genotype can infect humans, domestic animals (dogs and cats) and animals slaughtered for human consumption (pigs, sheep, goats, and chickens), suggesting a common infection route. However, little is known about the importance of free-living wild birds within this epidemiological context. The objective of this work was to isolate, genotype, and evaluate the virulence for mice of new isolates of T. gondii obtained from free-living wild birds from the state of Minas Gerais, Southeastern Brazil. From August 2016 to June 2017, T. gondii was isolated from the hearts and brains collected from 6 out of 45 free-living wild birds, namely, a roadside hawk (Rupornis magnirostris), a campo flicker (Colaptes campestris), a southern caracara (Caracara plancus) and a tropical screech-owl (Megascops choliba), all rescued in Belo Horizonte. One isolate was obtained from a toco toucan (Ramphastos toco), rescued in Cristiano Otoni, and another was obtained from southern caracara, rescued in Santa Luzia. Five different genotypes were identified by PCR-RFLP. A unique genotype was shared in two different isolates obtained from a southern caracara and a toco toucan. This genotype has never been previously described in any other host or place. Three isolates were classified as of intermediary virulence and three isolates as avirulent for mice. The combined analysis of alleles ROP18/ROP5 (a serine/threonine kinase, and a polymorphic pseudokinase, respectively) was effective in determining the virulence of five of all the isolates with the exception of that from R. magnirostris. Atypical isolates of T. gondii obtained from free-living wild birds rescued in the state of Minas Gerais share the same genotypes of strains that infect humans, domestic animals, and animals slaughtered for human consumption.

Serum biochemical values of some species of apparently healthy free-living wild birds in Zaria, Nigeria

The research was carried out to establish baseline serum biochemical parameters for some species of apparently healthy free-living wild birds in Zaria, Nigeria. A total of 133 free-living wild birds, belonging to seven species, comprising 20 each of Poicephalus senegalus (Senegal Parrot), Psittacula krameri (Rose-Ringed Parakeet), Streptopelia senegalensis (Laughing Dove), Treron waalia (Bruce’s Green Pigeon), 19 Columba guinea (Speckled Pigeons), 16 Streptopelia decipiens (Mourning Collar-Doves) and 18 Bubulcus ibis (Cattle Egrets) were used. The Audiocomb serum auto-analyser was used for the analyses. The highest mean glucose (154.70 ± 5.72 mg/dl), creatinine (0.49 ± 0.02 mg/dl) and urea (5.53 ± 0.28 mg/dl) concentrations were obtained from the apparently healthy Mourning Collar Dove, Bruce Green Pigeon and Speckled Pigeon, respectively. Except for mean serum calcium concentration of 2.64 ± 0.05 mg/dl which was highest in the apparently healthy Cattle Egret, the glucose (139.20 ± 4.64 mg/dl), urea (4.24 ± 0.15 mg/dl), total protein (6.65 ± 0.10 g/dl) and albumin (3.77 ± 0.10 g/dl) concentrations were lowest in this species of bird. The mean total protein concentration of 6.93 ± 0.10 g/dl and globulin concentration of 2.97 ± 0.04 g/dl were highest in the apparently healthy Laughing Dove. The apparently healthy Rose-Ringed Parakeet had the highest mean phosphorus concentration of 1.05 ± 0.03 mg/dl and lowest mean globulin fraction of 2.89 ± 0.05 g/dl. The range values for urea (4.40–7.20 mg/dl), calcium (2.53–3.01 mg/dl) and phosphorus (0.87–1.96 mg/dl) were obtained from the Speckled Pigeon, while the Mourning Collar-Dove had range value of 139–202 mg/dl for glucose concentration. In conclusion, there were interspecies variations in biochemical parameters of free-living wild birds in Zaria, Nigeria.

Dispersal and Transmission of Avian Paramyxovirus Serotype 4 among Wild Birds and Domestic Poultry.

Avian paramyxovirus serotype 4 (APMV-4) is found sporadically in wild birds worldwide, and it is an economically important poultry pathogen. Despite the existence of several published strains, very little is known about the distribution, host species, and transmission of APMV-4 strains. To better understand the relationships among these factors, we conducted an APMV-4 surveillance of wild birds and domestic poultry in six provinces of China suspected of being intercontinental flyways and sites of interspecies transmission. APMV-4 surveillance was conducted in 9,160 wild birds representing seven species, and 1,461 domestic poultry in live bird markets (LMBs) from December 2013 to June 2016. The rate of APMV-4 isolation was 0.10% (11/10,621), and viruses were isolated from swan geese, bean geese, cormorants, mallards, and chickens. Sequencing and phylogenetic analyses of the 11 isolated viruses indicated that all the isolates belonging to genotype I were epidemiologically connected with wild bird-origin viruses from the Ukraine and Italy. Moreover, chicken-origin APMV-4 strains isolated from the LBMs were highly similar to wild bird-origin viruses from nearby lakes with free-living wild birds. In additional, a hemagglutination-negative APMV-4 virus was identified. These findings, together with recent APMV-4 studies, suggest potential virus interspecies transmission between wild birds and domestic poultry, and reveal possible epidemiological intercontinental connections between APMV-4 transmission by wild birds.

Wild birds and urban pigeons as reservoirs for diarrheagenic Escherichia coli with zoonotic potential.

In order to describe the role of wild birds and pigeons in the transmission of shiga toxigenic Escherichia coli (STEC) and enteropathogenic Escherichia coli (EPEC) to humans and other animals, samples were collected from cloacae and oropharynx of free-living wild birds and free-living pigeons. Two STEC (0.8%) and five EPEC strains (2.0%) were isolated from wild birds and four EPEC strains (2.0%) were recovered from pigeons. Serogroups, sequence types (STs) and virulence genes, such as saa, iha, lpfA O113, ehxA, espA, nleB and nleE, detected in this study had already been implicated in human and animal diseases. Multidrug resistance (MDR) was found in 25.0% of the pigeon strains and in 57.0% of the wild bird strains; the wild birds also yielded one isolate carrying extended-spectrum β-lactamases (ESBLs) gene bla CTX-M-8. The high variability shown by PFGE demonstrates that there are no prevalent E. coli clones from these avian hosts. Wild birds and pigeons could act as carriers of multidrug-resistant STEC and EPEC and therefore may constitute a considerable hazard to human and animal health by transmission of these strains to the environment.

A Review of Gray Partridge Restocking in the UK and its Implications for the UK Biodiversity Action Plan

The gray partridge Perdix perdix has been the subject of many re-introduction projects throughout the world. In earlier attempts many releases simply aimed to increase the number of individuals for harvesting. This is very different from a conservation project aiming to establish a self-sustaining population. In recent decades, the gray partridge has declined severely in abundance and it is a species of conservation concern throughout Western Europe. Until now, gray partridge releasing projects have mainly focused on releasing large numbers of captive-reared individuals, of which few survive because of heavy predation and low breeding success. We reviewed the scientific and gamekeepering literature, and found that nevertheless a number of traditional methods for rearing and releasing gray partridges exist. Although these have primarily been developed to supplement existing wild stocks to produce shootable resources, some can be re-used today for conservation purposes. The most promising system for producing birds for re-introduction and supplementation purposes is to obtain eggs from a reliable source, hatch and rear the chicks under bantams to eight weeks of age, then foster to failed pairs of wild gray partridges. A less labour-intensive alternative is to hatch and raise chicks under artificial heat and foster these to unsuccessful wild pairs. Obviously these two systems are dependent on the presence of local free-living wild birds. If no pairs of wild gray partridges are present it is necessary to establish a founder population first. We see two methods to achieve this goal, the release of coveys in autumn or of pairs in spring. An important pre-requisite to any restocking scheme is appropriate management including the provision of suitable habitat for feeding and nesting and the control of predators, otherwise restocking is unlikely to lead to long-term establishment.

Multidrug-resistant pathogenic Escherichia coli isolated from wild birds in a veterinary hospital

ABSTRACTWild birds are carriers of Escherichia coli. However, little is known about their role as reservoirs for extra-intestinal pathogenic E. coli (ExPEC). In this work we investigated E. coli strains carrying virulence genes related to human and animal ExPEC isolated from free-living wild birds treated in a veterinary hospital. Multidrug resistance was found in 47.4% of the strains, but none of them were extended-spectrum beta-lactamase producers. Not only the virulence genes, but also the serogroups (e.g. O1 and O2) detected in the isolates of E. coli have already been implicated in human and bird diseases. The sequence types detected were also found in wild, companion and food animals, environmental and human clinical isolates in different countries. Furthermore, from the 19 isolates, 17 (89.5%) showed a degree of pathogenicity on an in vivo infection model. The isolates showed high heterogeneity by pulsed-field gel electrophoresis indicating that E. coli from these birds are clonally diverse. Overall, the results showed that wild birds can be reservoirs and/or vectors of highly pathogenic and multidrug-resistant E. coli that have the potential to cause disease in humans and poultry.