Feral animals in the urban environment

Genetic properties of conjugative R plasmids in Escherichia coli and Salmonella isolated from feral and domestic pigeons, crows and kites

Feral pigeons, common wood pigeons and Eurasian collared doves are the most common representatives of the Columbidae family in Switzerland and are mostly present in highly populated, urban areas. Pigeons may carry various members of the obligate intracellular Chlamydiaceae family, particularly Chlamydia (C.) psittaci, a known zoonotic agent, and C. avium. The objective of the study was to identify the infection rates of common free-roaming pigeons for different Chlamydia species with the overall aim to assess the risk pigeons pose to public health. In this study, 431 pigeons (323 feral pigeons, 34 domestic pigeons, 39 Eurasian collared doves, 35 common wood pigeons) from several geographic locations in Switzerland were investigated for the presence of Chlamydiaceae. Samples consisted of pooled choanal-cloacal swabs (n = 174), liver samples (n = 52), and paired swab and liver samples from 205 pigeons (n = 410). All 636 samples were screened using a Chlamydiaceae family-specific 23S rRNA real-time PCR (qPCR). Subsequent species identification was performed by DNA-microarray assay, sequencing of a 16S rRNA gene fragment and a C. psittaci specific qPCR. In total, 73 of the 431 pigeons tested positive for Chlamydiaceae, of which 68 were positive for C. psittaci, four were C. avium-positive and one pigeon was co-infected with C. avium and C. psittaci. The highest infection rates were detected in feral (64/323) and domestic pigeons (5/34). Common wood pigeons (2/35) and Eurasian collared doves (2/39) revealed lower infection rates. Additionally, multilocus sequence typing of twelve selected C. psittaci-positive samples revealed closely related sequence types (ST) between and within different Swiss cities. Furthermore, liver and corresponding swab samples from the same bird were colonized by the same ST. Considering the high infection rates of C. psittaci in domestic and feral pigeons, close or frequent contact to these birds poses a human health risk.

Salmonella typhimurium, Copenhagen variety was isolated from 13 domestic pigeons (Columba livia domestica) of 4 pigeonries in which clinical salmonellosis occurred during the period of 1970 to 1975. Of 58 composite fecal samples collected from feral pigeons (Columba livia domestica) in 13 districts of Honshu and Hokkaido in 1975 and 1976, 12 (20.7%) from 3 districts gave the same antigenic form. The antigenic form was also isolated from the tissues of 2 (1.8%) feral pigeons (Columba livia domestica) caught at one site among a total of 110 feral pigeons (80 Columba livia domestica and 30 Streptopelia orientalis orientalis) caught in 3 districts of Hokkaido in 1976. No Salmonella other than S. typhimurium, Copenhagen variety was obtained from pigeons. These isolates fermented maltose, and belonged to biovar 10 [2]. All the isolates from feral pigeons and most of those from domestic pigeons showed in-vitro drug sensitivity. S. typhimurium, Copenhagen variety having the same characteristics was isolated from animals, chickens and wild birds, though the antigenic form originating from hosts other than pigeons was drug resistant with variable frequencies, and different biovars were found in some hosts. This appears to indicate that pigeons have a role in the epizootiology of salmonellosis in animals and birds in Japan.

Pigeon paramyxovirus-1 (PPMV-1) is predominantly isolated from pigeons or doves and forms a separate group of viral strains within Avian Orthoavulavirus-1, the causative agent of Newcastle disease in poultry. Since the introduction of PPMV-1 into Europe in 1981, these strains have rapidly spread all over Europe, and are nowadays considered to be enzootic in feral and hobby pigeons (Columba livia domestica). Infections with PPMV-1 can range from asymptomatic to fatal. To assess whether PPMV-1 continuously circulates in healthy feral pigeons, 396 tissue samples of pigeons from the city of Zurich were tested by reverse transcriptase real-time PCR over the period of one year. PPMV-1-RNA was detected in 41 feral pigeons (10.35%), determined as the dominant European genotype VI.2.1.1.2.2. In 38 of the 41 pigeons where organ samples tested positive, PPMV-1-RNA was also detected in either choana or cloaca swabs. There were no significant differences in positivity rates between seasons, age, and sex. The current study shows that feral pigeons without clinical signs of disease can harbour and most likely excrete PPMV-1. Spill-over into free-range holdings of chickens are therefore possible, as observed in a recent outbreak of Newcastle disease in laying hens due to PPMV-1 genotype VI.2.1.1.2.2. in the canton of Zurich in January 2022.

Chlamydial infections in feral pigeons in Europe: Review of data and focus on public health implications

Domestic pigeons

-Domestic pigeons were derived from Rock Doves (Columba livia) by artificial selection perhaps 5,000 ybp. Feral pigeon populations developed after domestics escaped captivity; this began in Europe soon after initial domestications occurred and has continued intermittently in other regions. Ferals developed from domestic stocks in North America no earlier than 400 ybp and are genealogically closer to domestics than to European ferals or wild Rock Doves. Nevertheless, North American ferals are significantly closer in skeletal size and shape to European ferals and Rock Doves than to domestics. Natural selection evidently has been reconstituting reasonable facsimiles of wild size and shape phenotypes in feral pigeons of Europe and North America. Received 17 April 1991, accepted 13 January 1992. Man, therefore, may be said to have been trying an experiment on a gigantic scale; and it is an experiment which nature during the long lapse of time has incessantly tried [Darwin 1868]. Of the many kinds of animals examined for the study of variation under domestication by Charles Darwin, only for pigeons (Columba livia) did he describe fully the chief domestic strains, along with history, the amount and nature of their differences, and the probable steps by which they have been formed (Darwin 1868: 1 [vol. 1]). He did artificial selection and studied inheritance of plumage colors, color patterns, and body size and shape in domestic pigeons; the results of these studies were important to his work on natural selection (Darwin 1859, 1868). Darwin's findings supported the idea that the range of colors, patterns, sizes, and shapes shown by domestic strains had antecedents in the variation of wild Rock Doves. He also thought that feral pigeons were an understandable consequence of domestic birds escaping captivity. In the late 1850s, however, Darwin was heavily involved in writing his big book (Stauffer 1975), so origins of ferals from domestics were barely mentioned. Details of such origins, involving character variation molded presumably by natural selection, are nevertheless of interest to thinking concerning population differentiation; some details inferred from skeletal morphology are reported here. Rock Doves were domesticated in the period 10,000 to 5,000 ybp, earlier than has been previously suggested (e.g. Sossinka 1982). Domestications evidently occurred many times throughout the Mediterranean Basin, Near East, and southwestern Asia; this is known to be true in more recent time (Darwin 1868; N. E. Baldaccini, pers. comm.). Later, pigeons escaping captivity either rejoined wild colonies or became feral, and are now found in most of the world (Long 1981). European, North African, and Asiatic ferals may have histories of several thousand years. North American ferals have a significantly shorter history, stemming from British dovecote pigeons (the earliest of which were brought to Britain by the Romans; Levi 1974) introduced by Scottish and English immigrants to American Atlantic seaboard localities in 1600-1610 (Schorger 1952). North American ferals, therefore, are not directly lineally related to ferals of the Old World (Fig. 1). Additionally, founder gene frequencies seemingly departed significantly from those of European domestics, judging from allozymes of North American and European ferals (Johnston et al. 1989). Thus, the evolutionary derivation of ferals is more complex than it might have been. The complexity is most useful-it is, for example, important that feral pigeons were derived from domestics more than once, because the development of ferals in North America can be viewed as an independent replicate of the natural experiment in ferality tried in Europe and Asia. Without the replicate, this study would almost certainly not have been undertaken, nor would it in any event have a satisfactory conclusion. Getting to that conclusion employs assessment of skeletal similarities and differences among wild, domestic, and the two feral lines of Rock Doves, and approximating how the similarities and differences could have occurred.

On the epidemiology, biology and food-dependent reproduction of the feral pigeon (Columba livia)

<p>Urban areas and human populations are growing. Cities provide highly modified habitat for species that can adapt their feeding and other behaviours. The growth of urban landscapes and human populations may result in an increase in human-wildlife conflict. Businesses which prepare and sell food (food establishments) may be more likely to encounter conflict with urban wildlife, which may lead to negative attitudes towards urban wildlife. Negative attitudes towards wildlife could create polarised communities and possibly affect the success of environmental initiatives. This study sought to understand (1) how feral pigeons use urban environments and the resources key to their distribution and congregation; (2) whether feral pigeons are food limited in Wellington City; and (3) how the interactions of owners and managers of food establishments with feral pigeons influence their attitudes to feral pigeons. I used 8 transects through the central City which covered a representative sample of urban habitats, including the central business district, green space, and waterfront to estimate resource selection. Bird capture and banding were used to determine feral pigeon condition at a range of sites across the City and included a mix of high, medium and low anthropogenic fed sites. A written survey of owners and managers of food establishments in Wellington was conducted to evaluate attitudes to feral pigeons (n = 62). Feral pigeon resource selection is mainly influenced by people and where they choose to eat (∆AIC ≤ W = 0.999), such as sites with outdoor seating where people may directly feed feral pigeons. However, once a site has been selected, areas with tertiary vegetation and disposed food (W = 0.324 and W = 0.297) are the most likely to attract larger flocks of feral pigeons (although a number of other variables also influence flock size, such as availability of freshwater). Feral pigeons do not appear to be food limited in Wellington as condition was not significantly different between sites (n=48, body condition, (body mass/tarsus length) Kruskal-Wallis = 2.06, p = 0.36; keel condition, Kruskal-Wallis = 0.7283, p = 0.6948; feather condition Kruskal-Wallis = 2.7943, p = 0.2473). Attitudes of food establishment owners and managers towards feral pigeons are most influenced by how often they see feral pigeons (∆AICc ≤ W = 0:465). Therefore, direct experience rather than knowledge, engagement, action or socio-demographics has the most influence on attitudes of owners and managers of food establishments. These results suggest that feral pigeon populations are largely dependent on the availability of anthropogenic foods. Reducing the food provided by people may limit feral pigeon populations. Reductions in pigeon populations are also likely to change attitudes of business owners and reduce conflict because they will be less likely to encounter pigeons. Limiting feeding and access to food waste is probably the most effective way of managing pigeon populations.</p>

<p>Urban areas and human populations are growing. Cities provide highly modified habitat for species that can adapt their feeding and other behaviours. The growth of urban landscapes and human populations may result in an increase in human-wildlife conflict. Businesses which prepare and sell food (food establishments) may be more likely to encounter conflict with urban wildlife, which may lead to negative attitudes towards urban wildlife. Negative attitudes towards wildlife could create polarised communities and possibly affect the success of environmental initiatives. This study sought to understand (1) how feral pigeons use urban environments and the resources key to their distribution and congregation; (2) whether feral pigeons are food limited in Wellington City; and (3) how the interactions of owners and managers of food establishments with feral pigeons influence their attitudes to feral pigeons. I used 8 transects through the central City which covered a representative sample of urban habitats, including the central business district, green space, and waterfront to estimate resource selection. Bird capture and banding were used to determine feral pigeon condition at a range of sites across the City and included a mix of high, medium and low anthropogenic fed sites. A written survey of owners and managers of food establishments in Wellington was conducted to evaluate attitudes to feral pigeons (n = 62). Feral pigeon resource selection is mainly influenced by people and where they choose to eat (∆AIC ≤ W = 0.999), such as sites with outdoor seating where people may directly feed feral pigeons. However, once a site has been selected, areas with tertiary vegetation and disposed food (W = 0.324 and W = 0.297) are the most likely to attract larger flocks of feral pigeons (although a number of other variables also influence flock size, such as availability of freshwater). Feral pigeons do not appear to be food limited in Wellington as condition was not significantly different between sites (n=48, body condition, (body mass/tarsus length) Kruskal-Wallis = 2.06, p = 0.36; keel condition, Kruskal-Wallis = 0.7283, p = 0.6948; feather condition Kruskal-Wallis = 2.7943, p = 0.2473). Attitudes of food establishment owners and managers towards feral pigeons are most influenced by how often they see feral pigeons (∆AICc ≤ W = 0:465). Therefore, direct experience rather than knowledge, engagement, action or socio-demographics has the most influence on attitudes of owners and managers of food establishments. These results suggest that feral pigeon populations are largely dependent on the availability of anthropogenic foods. Reducing the food provided by people may limit feral pigeon populations. Reductions in pigeon populations are also likely to change attitudes of business owners and reduce conflict because they will be less likely to encounter pigeons. Limiting feeding and access to food waste is probably the most effective way of managing pigeon populations.</p>

Worldwide urban pigeons (Columba livia domestica) are an important reservoir of pathogenic and multidrug-resistant bacteria (MDR). Plasmids are key genetic elements in the dissemination of antimicrobial drug resistance in bacteria, including beta-lactams and quinolones, which are the most important classes of drugs for treatment of Enterobacteriaceae infections in human and veterinary medicine. The aim of this study was to determine the presence of Escherichia coli (E. coli) harboring plasmids containing extend-spectrum (ESBL) and pAmpC beta-lactamases, also plasmid-mediated quinolone resistance (PMQR) genes in urban pigeons from São Paulo State, Brazil. A collection of 107 isolates of E. coli from urban pigeons from four cities was screened by antimicrobial resistance phenotypic and PCR for genes encoding ESBL, pAmpC and PMQR genes. Clonality was evaluated by ERIC-PCR. We found three strains positive for blaCTX-M genes. In two clonally related CTX-M-8-producing strains, the gene was associated with IncI1 plasmids. An MDR strain harboring blaCTX-M-2, the plasmid could not be transferred. No strain was positive for PMQR genes. These results indicate that CTX-M-2 and CTX-M-8-producing E. coli are present in urban pigeons, which could serve as a reservoir for ESBL-producing E. coli in Brazil.

Immigrant Positioning in Twentieth-Century Mexico: Middle Easterners, Foreign Citizens, and Multiculturalism

Parasitic infections are frequent in cosmopolitan feral pigeons (Columba livia domestica) that live in cities, but little is known about the effects of parasites in urban feral pigeon populations. A survey was conducted to evaluate the occurrence of endoparasites and the risk factors of feral pigeons in the city of Loja in southern Ecuador between August and October 2019. A total of 166 fecal samples and 80 peripheral blood smears were collected and examined by the McMaster flotation method and Giemsa staining, respectively. The prevalence of gastrointestinal parasites was 79.51% (132/166). Parasites included: Ascaridia columbae in 13.64% (18/132), Capillaria sp. in 3.79% (5/132), Eimeria sp. in 25% (33/132), unidentified coccidia in 75% (99/132), and an unidentified nematode egg in 0.7% (1/132). The presence of intracellular gamonts of Haemoproteus sp. was found in 87.50% (70/80) of examined blood smears. The frequency and intensity of nematodes were different according to the site. Haemoproteus infection was more frequent in individuals with low body mass index. More research should be undertaken to understand parasitic infections and their effects on cosmopolitan synanthropic feral pigeons.

Background: Feral pigeons (Columba livia domestica) live and breed in many city centres and contact with their droppings can be a hazard for human health if the birds carry Chlamydia psittaci.Objective: The aim of this study was to establish whether pigeon droppings in two Dutch cities (Utrecht and Haarlem) contain C. psittaci and/or C. avium, which could be a potential hazard for transmission to humans.Methods: In May 2017 seven feral pigeon ‘hot spots’ with between 5 and 40+ pigeons present were identified in two cities by visual observations over two days. During the following ten days fresh droppings were collected at these hot spots and the samples were pooled per three droppings to achieve 40–41 samples per city. Samples were analysed for Chlamydia DNA with a broad range 23S Chlamydiaceae Real-Time PCR and positive samples were tested with a specific C. psittaci and C. avium Real-Time PCR. Positive C. psittaci samples were genotyped.Results: C. psittaci and C. avium were detected in both cities. For C. psittaci the prevalences in Utrecht and Haarlem were 2.4% and 7.5%, respectively; for C. avium 36.6% and 20.0%, respectively. One sample contained both species. All C. psittaci samples belonged to genotype B.Conclusion: C. psittaci and C. avium are present in feral pigeon droppings in Utrecht and Haarlem. Human contact with droppings from infected pigeons or inhalation of dust from dried droppings represent a potential hazard to public health.

Feral Pigeons (Columba livia f. urbana), descendants of domesticated pigeons, are highly adapted to urban environments. However, comprehensive genetic studies using the mitochondrial DNA (mtDNA) of them have been scarce. This study evaluated the genetic variability and structure of Feral Pigeons from six urban locations in Spain and Lithuania, comparing them to a population of Feral Pigeons from Taiwan. Additionally, comparisons were made with domestic pigeon breeds and two Columbidae species associated with forest habitats: the Woodpigeon (Columba palumbus) and the European Turtle Dove (Streptopelia turtur). Genetic diversity was assessed using mtDNA D-loop sequences. Among the Feral Pigeons, a low level of genetic diversity was observed (Hd = 0.732; π = 0.00330), with 12 haplotypes forming a star-like network. A single haplotype was shared by nearly half of the individuals, and all haplotypes identified in Taiwan were also present in European populations. No genetic differentiation was found among pigeons within the same country, but significant divergence was observed between the European and Taiwanese populations. Compared to domestic pigeon breeds, Feral Pigeons exhibited slightly higher variability, although both groups were considerably less diverse than the Woodpigeon and European Turtle Dove. The Turtle Dove showed the highest genetic diversity, likely due to its complex phylogeography and migratory patterns. Neutrality tests indicated a recent population expansion in the Woodpigeon, following a bottleneck event. Overall, the results revealed limited genetic variability in Feral Pigeons, contrasting with the greater diversity and broader genetic structure observed in wild Columbidae species analysed. Keywords: Feral pigeon; Woodpigeon; European Turtle Dove; mtDNA; D-loop; genetic variability; population structure