Screening of feral pigeon (Colomba livia), mallard (Anas platyrhynchos) and graylag goose (Anser anser) populations for Campylobacter spp., Salmonella spp., avian influenza virus and avian paramyxovirus

Molecular detection of multidrug and methicillin resistance in Staphylococcus aureus isolated from wild pigeons (Columba livia) in South Africa

Staphylococcus aureus is an important human and veterinary pathogen. The present study aimed to determine the prevalence of antibiotic resistance among S. aureus isolated from samples obtained from free-flying wild pigeons and houseflies from different locations surrounding a local hospital in the Greater Durban area in KwaZulu-Natal Province, South Africa. Environmental fecal samples were obtained from wild pigeons that inhabits the grounds of a local public hospital located on the South Beach area, Durban, South Africa. Housefly samples were collected from three different locations (Kenneth Stainbank Nature Reserve, Montclair/Clairwood, and Glenwood/Berea) in the greater Durban area, all within a close proximity to the hospital. Following enrichment, identification, and antimicrobial resistance profiling, S. aureus isolates were subjected to DNA extraction using the boiling method. It was found that 57 out of 252 samples (22.62%) were positive for S. aureus. The Kirby-Bauer disk diffusion method of antibiotic susceptibility testing was performed and revealed that antibiotic resistance rates to penicillin and rifampicin were the most common, with both returning 48 (84.2%) out of the 57 S. aureus isolates being resistant to penicillin and rifampicin. Antibiotic resistance rates to clindamycin, linezolid, erythromycin, tetracycline, cefoxitin, and ciprofloxacin were 82.5%, 78.9%, 73.7%, 63.2%, 33.3%, and 15.8% respectively. Antibiotic resistance genes were detected using primer-specific PCR and it was found that the prevalence rates of tetM, aac(6')-aph(2″), mecA, tetK, ermc, and blaZ genes were 66.7%, 40.4%, 40.4%, 38.6%, 24.6%, and 3.51% respectively. Statistical analysis revealed significant (p < 0.05) relationships between the tetM, aac(6')-aph(2″), and ermC genes and all parameters tested. A significant correlation between the aac(6')-aph(2″) gene and the tetM (0.506) and ermC (-0.386) genes was identified. It was found that 23 (40.3%) S. aureus isolates were mecA positive, of which 10 (52.6%) out of 19 cefoxitin-resistant isolates were mecA positive and 13 (35.1%) out of 37 cefoxitin-sensitive isolates were mecA positive. The results of the present study demonstrated the detection of methicillin and multidrug resistant S. aureus isolated from samples obtained from wild pigeons and houseflies in the surroundings of a local public hospital in the Greater Durban area in South Africa. The findings of the study may account for the emergence of multidrug-resistant staphylococcal infections. The findings highlight the significant role of wild pigeons and houseflies in the spread of drug-resistant pathogenic S. aureus including MRSA. The conclusions of the present study highlight the improtant role of wildlife and the environment as interconnected contributors of One Health.

Role of Free-Ranging Synanthropic Egyptian Geese (Alopochen aegyptiaca) as Natural Host Reservoirs for Salmonella spp. in Germany

Salmonella is one of the most common and pathogenic bacteria worldwide, causing severe enteritis in humans and representing a relevant intestinal illness in One Health for young, old and immunosuppressed patients. Various Salmonella serovars have been described to be responsible for human Salmonellosis. Birds represent natural carriers of different zoonotic-relevant Salmonella serovars and Anseriformes can not only transmit Salmonella spp. to humans but also manifest clinical Salmonellosis. In this study, 138 scat samples (n = 138) of free-ranging Egyptian geese (EG; Alopochen aegyptiaca) were collected in Germany, including 83 scat samples from city parks, 30 samples from 14 public swimming pools and 25 fresh caecal samples of dead EG. Collected EG scat samples were examined for the presence of Salmonella spp. according either to the ISO 6579 (2017) norm or to a combination of bacterial pre-enrichment and specific PCR for detection of Salmonella DNA. All 138 analysed EG faecal samples resulted Salmonella-negative. Furthermore, the survival of Salmonella enterica subsp. enterica Serovar Anatum in spiked EG droppings was tested in four different concentrations of chlorinated pool water. In vitro testing demonstrated that S. Anatum-spiked EG droppings were still infectious for up to six hours in chlorinated pool water according to current German regulations for public swimming pools. This study is to be considered as a baseline investigation to clarify the role of synanthropic EG as natural carriers of zoonotic Salmonella in cities; nonetheless, large-scale epidemiological studies, including higher numbers of samples as well as more urban locations, are needed for final conclusions on the occurrence of this intestinal bacteria in neozootic EG.

A Systematic Review on the Role of Wildlife as Carriers and Spreaders of Campylobacter spp

Campylobacter spp. are important zoonotic pathogens and can cause one of the main bacterial diarrheal diseases worldwide. Research in the context of infection arising from transmission from other humans and other vertebrates has been extensive. A large fraction of these investigations has focused on domestic animals; however, there are also a number of publications which either totally, or at least in part, consider the role of wild or feral animals as carriers or spreaders of Campylobacter spp. Here, we carry out a systematic review to explore the role played by wild vertebrates as sources of Campylobacter spp. with a compilation of prevalence data for more than 150 species including reptiles, mammals and birds. We found that numerous vertebrate species can act as carriers of Campylobacter species, but we also found that some host specificity may exist, reducing the risk of spread from wildlife to domestic animals or humans.

Screening of Healthy Feral Pigeons (Columba livia domestica) in the City of Zurich Reveals Continuous Circulation of Pigeon Paramyxovirus-1 and a Serious Threat of Transmission to Domestic Poultry

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.

Wild Duck (Anas platyrhynchos) as a Source of Antibiotic-Resistant Salmonella enterica subsp. diarizonae O58—The First Report in Poland

The “One Health” approach increasingly demonstrates the global spread of pathogenic microorganisms and their antimicrobial resistance in the environment, both in animals and humans. Salmonella enterica subsp. diarizonae is nowadays very often isolated from cold-blooded reptiles to a lesser extent from sheep, but unfortunately more and more often from humans. However, there are a few studies describing the isolation of Salmonella enterica subsp. diarizonae from migratory wild birds. The mallard duck (Anas platyrhynchos), a wild animal that traverses the continent of Eurasia, can be an excellent indicator of the spread of intestinal microbes as well as their resistance to antibiotics. This is the first report of the Salmonella enterica subsp. diarizonae detection in Poland in a migrating mallard duck. This research presented the identification difficulties associated with the isolation of Salmonella enterica subsp. diarizonae using three different biochemical tests and advanced serology tests. At the same time, we detected very high antimicrobial resistance in the isolated strain. By using the minimum inhibitory concentration (MIC) method, it was found that the isolated strain of S. enterica subsp. diarizonae has high antibiotic resistance against 14 of the 33 tested antimicrobials agents. The resistance genes that have been identified in S. enterica subsp. diarizonae include aadA, strA/strB, and bla_TEM.

Multidrug-resistant Escherichia coli and Salmonella spp. isolated from pigeons

Background and Aim:

Pigeon rearing has been gaining popularity for recent years. They are reared remarkably very close to the house of the owner. This activity, therefore, may pose potential threats for humans as well as other animals as pigeons may carry and spread different pathogens including drug-resistant bacteria. This study was conducted to explore the prevalence of Escherichia coli and Salmonella spp. as well as their antibiogram profile along with an association analysis.

Materials and Methods:

Forty swab samples were collected from 20 pigeons during the study. E. coli and Salmonella spp. were isolated and identified on various types of agars, including MacConkey, Eosin methylene blue, Brilliant green, and Salmonella-Shigella agar. Biochemical tests such as the carbohydrate fermentation test, the triple sugar iron agar slant reaction, the indole test, the methyl red test, the catalase test, as well as the Voges–Proskauer test were also performed. Besides, the presence of E. coli was further confirmed by polymerase chain reaction (PCR). Moreover, antimicrobial susceptibility testing of the isolates was performed against nine antibiotics from seven classes on the Mueller-Hinton agar based on the Kirby–Bauer disk diffusion method.

Results:

The overall prevalence of E. coli and Salmonella spp. was 52.5 and 27.5%, respectively. The prevalence of the pathogenic E. coli was 61.90%. The antibiogram profile of 21 E. coli as well as 11 Salmonella spp. revealed that all isolates, except one, were resistant to one to six antibiotics. Around 61.90%, 71.43%, 23.81%, 61.90%, 23.81%, 19.05%, and 52.38% of E. coli showed resistance against amoxicillin, ampicillin, azithromycin, erythromycin, nalidixic acid, gentamicin, and tetracycline, respectively. Furthermore, E. coli resistance was not observed in case of ciprofloxacin and levofloxacin. Similarly, around 36.36%, 27.27%, 27.27%, 45.45%, 81.82%, 100%, and 18.18% of the Salmonella spp. showed resistance against amoxicillin, ampicillin, azithromycin, erythromycin, nalidixic acid, tetracycline, and levofloxacin, respectively. However, all Salmonella spp. (100%) were found to show sensitivity against ciprofloxacin and gentamicin. Multidrug-resistant (MDR) E. coli (23.80%) and Salmonella spp. (54.54%) were also isolated. Furthermore, both positive (odds ratio [OR] >1) and negative (OR <1) drug resistance associations, with a higher frequency of positive associations, were found in E. coli. A significant positive association was observed between ampicillin and amoxicillin (OR: 81.67, 95% confidence interval: 2.73-2447.57, p=0.01).

Conclusion:

Pigeon carrying MDR E. coli and Salmonella spp. may contribute to the transmission and spread of these microorganisms. Therefore, strict hygienic measures should be taken during the farming of pigeons to decrease the potential transmission of E. coli and Salmonella spp. from pigeon to humans as well as other animals. So far, this is the first report of the PCR-based identification of pathogenic E. coli from pigeons in Bangladesh.

Are we overestimating risk of enteric pathogen spillover from wild birds to humans?

Enteric illnesses remain the second largest source of communicable diseases worldwide, and wild birds are suspected sources for human infection. This has led to efforts to reduce pathogen spillover through deterrence of wildlife and removal of wildlife habitat, particularly within farming systems, which can compromise conservation efforts and the ecosystem services wild birds provide. Further, Salmonella spp. are a significant cause of avian mortality, leading to additional conservation concerns. Despite numerous studies of enteric bacteria in wild birds and policies to discourage birds from food systems, we lack a comprehensive understanding of wild bird involvement in transmission of enteric bacteria to humans. Here, we propose a framework for understanding spillover of enteric pathogens from wild birds to humans, which includes pathogen acquisition, reservoir competence and bacterial shedding, contact with people and food, and pathogen survival in the environment. We place the literature into this framework to identify important knowledge gaps. Second, we conduct a meta‐analysis of prevalence data for three human enteric pathogens, Campylobacter spp., E. coli, and Salmonella spp., in 431 North American breeding bird species. Our literature review revealed that only 3% of studies addressed the complete system of pathogen transmission. In our meta‐analysis, we found a Campylobacter spp. prevalence of 27% across wild birds, while prevalence estimates of pathogenic E. coli (20%) and Salmonella spp. (6.4%) were lower. There was significant bias in which bird species have been tested, with most studies focusing on a small number of taxa that are common near people (e.g. European starlings Sturnus vulgaris and rock pigeons Columba livia) or commonly in contact with human waste (e.g. gulls). No pathogen prevalence data were available for 65% of North American breeding bird species, including many commonly in contact with humans (e.g. black‐billed magpie Pica hudsonia and great blue heron Ardea herodias), and our metadata suggest that some under‐studied species, taxonomic groups, and guilds may represent equivalent or greater risk to human infection than heavily studied species. We conclude that current data do not provide sufficient information to determine the likelihood of enteric pathogen spillover from wild birds to humans and thus preclude management solutions. The primary focus in the literature on pathogen prevalence likely overestimates the probability of enteric pathogen spillover from wild birds to humans because a pathogen must survive long enough at an infectious dose and be a strain that is able to colonize humans to cause infection. We propose that future research should focus on the large number of under‐studied species commonly in contact with people and food production and demonstrate shedding of bacterial strains pathogenic to humans into the environment where people may contact them. Finally, studies assessing the duration and intensity of bacterial shedding and survival of bacteria in the environment in bird faeces will help provide crucial missing information necessary to calculate spillover probability. Addressing these essential knowledge gaps will support policy to reduce enteric pathogen spillover to humans and enhance bird conservation efforts that are currently undermined by unsupported fears of pathogen spillover from wild birds.

Evidence of the role of free-living birds as disseminators of Salmonella spp

ABSTRACT This study aimed to review aspects of Salmonella spp. in free-living birds and their potential as disseminators for domestic animals, man, and the environment. Isolation of Salmonella spp. have been reported in several species of wild birds from Passeridae and Fringillidae, among other avian families, captured in countries of North America and Europe, where Salmonella ser. Typhimurium is the most frequently reported serotype. The presence of pathogens, including Salmonella, may be influenced by several factors, such as diet, environment, exposure to antibiotics, infection by pathogenic organisms and migration patterns. Researches with wild birds that live in urbanized environment are important, considering that birds may participate in the transmission of zoonotic pathogens, which are more prevalent in cities due to the human activity. Based on the information collected, this article concludes that wild birds are still important disseminators of pathogens in several geographic regions and may affect man, domestic animals, and other birds.

A ten-year-surveillance program of zoonotic pathogens in feral pigeons in the City of Madrid (2005-2014): The importance of a systematic pest control

Feral pigeons have increased in urban settings worldwide becoming a potential health risk for humans and other animals. Control and surveillance programs are essential to prevent the possible transmission of zoonotic pathogens carried by pigeons. A surveillance program was carried out in Madrid City (Spain) during 2005-2014 to determine the role of urban pigeons as carriers of zoonotic agents comparing these results with studies performed elsewhere in the last fifteen years. A total of 1372 pigeons were randomly captured and tested for detection of Antimicrobial susceptibility and genetic heterogeneity of Campylobacter and Salmonella isolates were determined. During the first phase (August 2005-July 2010), 428 animals were analyzed individually, while in the second period (August 2010-December 2014), 944 pigeons were analyzed in pools (n = 2-3 in 2010 and n = 5-6 in 2013 and 2014). The most prevalent pathogen during the first phase was Campylobacter spp., (6.57%, 95% confidence interval 3.05-12.10%) followed by Salmonella spp. (4.41%, 95% CI: 2.30-7.58%) and C. psittaci (2.56%, 95% CI: 0.70-6.53%)]. The PCR techniques, used during the 2010-2014 phase of the study, confirmed the presence of Campylobacter spp. (prevalence of 0-14.83%) and C. psittaci (0-12,94%) among pigeons of Madrid. Antimicrobial susceptibility testing suggested low levels of resistance. Presence of zoonotic agents in feral pigeons highlights the importance of surveillance programs on this species, although the relative low prevalence found suggests a limited risk to Public and Animal Health in Madrid.

Assessing the contributions of intraspecific and environmental sources of infection in urban wildlife: Salmonella enterica and white ibis as a case study

Conversion of natural habitats into urban landscapes can expose wildlife to novel pathogens and alter pathogen transmission pathways. Because transmission is difficult to quantify for many wildlife pathogens, mathematical models paired with field observations can help select among competing transmission pathways that might operate in urban landscapes. Here we develop a mathematical model for the enteric bacteria Salmonella enterica in urban-foraging white ibis ( Eudocimus albus) in south Florida as a case study to determine (i) the relative importance of contact-based versus environmental transmission among ibis and (ii) whether transmission can be supported by ibis alone or requires external sources of infection. We use biannual field prevalence data to restrict model outputs generated from a Latin hypercube sample of parameter space and select among competing transmission scenarios. We find the most support for transmission from environmental uptake rather than between-host contact and that ibis-ibis transmission alone could maintain low infection prevalence. Our analysis provides the first parameter estimates for Salmonella shedding and uptake in a wild bird and provides a key starting point for predicting how ibis response to urbanization alters their exposure to a multi-host zoonotic enteric pathogen. More broadly, our study provides an analytical roadmap to assess transmission pathways of multi-host wildlife pathogens in the face of scarce infection data.

Migratory birds along the Mediterranean – Black Sea Flyway as carriers of zoonotic pathogens

At the crossroad between Europe, Asia, and Africa, Bulgaria is part of the Mediterranean – Black Sea Flyway (MBSF) used by millions of migratory birds. In this study, bird species migrating through Bulgaria were investigated as carriers of zoonotic pathogens. In total, 706 birds belonging to 46 species were checked for the presence of various bacterial pathogens (Campylobacter, Yersinia, Salmonella, Listeria, Escherichia coli, Staphylococcus aureus, Francisella tularensis, Coxiella burnetii, Borrelia burgdorferi, and Brucella spp.). From 673 birds we investigated fecal samples, from the remaining 33, blood samples. We detected Campylobacter 16S rDNA gene in 1.3% of birds, but none were of pathogenic Campylobacter jejuni and Campylobacter coli species. Escherichia coli 16S rDNA gene was found in 8.8% of the birds. Out of 34 birds that transported Yersinia enterocolitica strains (5.05%), only 1 carried a pathogenic isolate. Three birds (0.4%) were carriers of nonpathogenic Salmonella strains. Four avian samples (0.6%) were positive for Listeria monocytogenes and 1 (0.15%) was positive for Brucella spp. None of the birds tested carried the tick-borne pathogens C. burnetii or B. burgdorferi sensu lato. Antibiotic-resistant strains were detected, suggesting that migratory birds could be reservoirs and spreaders of bacterial pathogens as well as antibiotic resistance genes.

Zoonotic Agents in Feral Pigeons (Columba livia) from Costa Rica: Possible Improvements to Diminish Contagion Risks

Most studies on zoonotic agents in pigeons have been conducted in the Palearctic region, but the scarcity of data is notorious in the Neotropical region, where these birds can breed all year around and are in close contact with humans. In this study, we used a combination of culture-dependent and culture-independent methods to identify infectious agents in 141 fecal samples from pigeons collected at four urban parks from Costa Rica. Of these we identified 34 positive samples for Salmonella enterica subsp. enterica serovar Braenderup (24.1%), 13 for Chlamydophila psittaci (9.2%), 9 for enteropathogenic Escherichia coli (6.4% eaeA, 0% stx-1 and 0% stx-2), and 2 for Campylobacter jejuni (1.4%). These populations of pigeons pose low risk for healthy adult humans, however, they may pose a health risk to immunocompromised patients or children. This study provides scientific data, which can be incorporated into educational programs aiming to reverse the public attitude toward pigeon feeding and to rationally justify population control efforts.

Potential disease transmission from wild geese and swans to livestock, poultry and humans: a review of the scientific literature from a One Health perspective

There are more herbivorous waterfowl (swans and geese) close to humans, livestock and poultry than ever before. This creates widespread conflict with agriculture and other human interests, but also debate about the role of swans and geese as potential vectors of disease of relevance for human and animal health. Using a One Health perspective, we provide the first comprehensive review of the scientific literature about the most relevant viral, bacterial, and unicellular pathogens occurring in wild geese and swans. Research thus far suggests that these birds may play a role in transmission of avian influenza virus, Salmonella, Campylobacter, and antibiotic resistance. On the other hand, at present there is no evidence that geese and swans play a role in transmission of Newcastle disease, duck plague, West Nile virus, Vibrio, Yersinia, Clostridium, Chlamydophila, and Borrelia. Finally, based on present knowledge it is not possible to say if geese and swans play a role in transmission of Escherichia coli, Pasteurella, Helicobacter, Brachyspira, Cryptosporidium, Giardia, and Microsporidia. This is largely due to changes in classification and taxonomy, rapid development of identification methods and lack of knowledge about host specificity. Previous research tends to overrate the role of geese and swans as disease vectors; we do not find any evidence that they are significant transmitters to humans or livestock of any of the pathogens considered in this review. Nevertheless, it is wise to keep poultry and livestock separated from small volume waters used by many wild waterfowl, but there is no need to discourage livestock grazing in nature reserves or pastures where geese and swans are present. Under some circumstances it is warranted to discourage swans and geese from using wastewater ponds, drinking water reservoirs, and public beaches. Intensified screening of swans and geese for AIV, West Nile virus and anatid herpesvirus is warranted.

Source tracking of Enterococcus moraviensis and E. haemoperoxidus

Enterococci were detected occasionally in 100 L samples of water abstracted from a shallow aquifer in a natural dune infiltration area for drinking water production. Enterococcus moraviensis was the species most frequently identified in these samples. Because there are no existing reports of faecal sources of E. moraviensis and the closely related E. hemoperoxidus, this study aimed to find such sources of these two species in the dunes. Faecal samples from various animal species living in the vicinity of abstraction wells, were analysed for enterococci on Slanetz and Bartley Agar. From these samples, enterococci isolates (1,386 in total) were subsequently identified using matrix assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry. E. moraviensis was found in the faeces of geese, foxes and rabbits. Also, E. haemoperoxidus was isolated from goose faeces. Using hierarchical clustering, the species composition of Enterococcus spp. isolated from abstracted water formed one cluster with the species composition found in geese droppings. A sanitary survey supported the indication that feral geese may provide a substantial faecal load in particular parts of this dune infiltration area, close to the water abstraction system. This study confirms the faecal origin of E. moraviensis and E. haemoperoxidus from specific animals, which strengthens their significance as faecal indicators.

ISOLATION AND MOLECULAR IDENTIFICATION OF POTENTIALLY PATHOGENIC Escherichia coli AND Campylobacter jejuni IN FERAL PIGEONS FROM AN URBAN AREA IN THE CITY OF LIMA, PERU

Feral pigeons (Columbia livia) live in close contact with humans and other animals. They can transmit potentially pathogenic and zoonotic agents. The objective of this study was to isolate and detect strains of diarrheagenic Escherichia coli and Campylobacter jejuni of urban feral pigeons from an area of Lima, Peru. Fresh dropping samples from urban parks were collected for microbiological isolation of E. coli strains in selective agar, and Campylobacter by filtration method. Molecular identification of diarrheagenic pathotypes of E.coli and Campylobacter jejuni was performed by PCR. Twenty-two parks were sampled and 16 colonies of Campylobacter spp. were isolated. The 100% of isolates were identified as Campylobacter jejuni. Furthermore, 102 colonies of E. coliwere isolated and the 5.88% resulted as Enteropathogenic (EPEC) type and 0.98% as Shiga toxin-producing E. coli (STEC). The urban feral pigeons of Lima in Peru can act as a reservoir or carriers of zoonotic potentially pathogenic enteric agents.

Prevalence and risk factors for Campylobacter spp., Salmonella spp., Coxiella burnetii, and Newcastle disease virus in feral pigeons (Columba livia) in public areas of Montreal, Canada

Feral pigeons (Columbia livia) can harbor a range of zoonotic pathogens. A transversal study was undertaken to estimate the prevalence of feral pigeons infected by various pathogens in public areas in Montreal, Quebec. Cloacal swabs from captured birds were cultured for Salmonella spp. and Campylobacter spp. and tested by real-time polymerase chain reaction (RT-PCR) for the detection of Coxiella burnetii. An oropharyngeal swab was also submitted to real-time reverse-transcription polymerase chain reaction (RRT-PCR) for the detection of Newcastle disease virus. Among the 187 pigeons tested from 10 public areas, 9.1% (95% CI: 3.0 to 15.2) were positive for Campylobacter spp. with all strains identified as Campylobacter jejuni. The Campylobacter status of birds was not associated with individual characteristics of birds, with the exception of body score. None of the pigeons tested positive for the other pathogens. Direct or indirect contacts with feral pigeons may constitute a potential risk for Campylobacter infection in humans.

Epidemiological survey of zoonotic pathogens in feral pigeons (Columba livia var. domestica) and sympatric zoo species in Southern Spain

A cross-sectional study was carried out to determine the prevalence of pathogenic zoonotic agents (flaviviruses, avian influenza viruses (AIVs), Salmonella spp. and Toxoplasma gondii) in feral pigeons and sympatric zoo animals from Córdoba (Southern Spain) between 2013 and 2014. Antibodies against flaviviruses were detected in 7.8% out of 142 (CI95%: 3.7-11.8) pigeons, and 8.2% of 49 (CI95%: 0.9-15.4) of zoo animals tested. Antibodies with specificity against West Nile virus (WNV) and Usutu virus (USUV) were confirmed both in pigeons and in zoo birds. Even though seropositivity to AIVs was not detected in any of the analyzed pigeons, 17.9% of 28 (CI95%: 3.7-32.0) zoo birds tested showed positive results. Salmonella spp. was not isolated in any of 152 fecal samples collected from pigeons, while 6.8% of 44 zoo animals were positive. Antibodies against T. gondii were found in 9.2% of 142 (CI95%: 4.8-13.6) feral pigeons and 26.9% of 108 (CI95%: 19.6-34.1) zoo animals. This is the first study on flaviviruses and T. gondii in feral pigeons and captive zoo species in Spain. Antibodies against WNV and USUV detected in non-migratory pigeons and captive zoo animals indicate local circulation of these emerging pathogens in the study area. T. gondii was widespread in species analyzed. This finding could be of importance for Public Health and Conservation of endangered species present in zoo parks. Pigeons and zoo animals may be included as sentinel species for monitoring zoonotic pathogens in urban areas.

High Prevalence and Genetic Diversity of Campylobacter jejuni in Wild Crows and Pigeons

The occurrence, seasonal variation and genetic diversity of Campylobacter spp. in pigeons and crows over a 1-year period were evaluated. Campylobacter spp. were isolated from 166 (34.6 %) out of 480 wild bird faecal samples. The occurrence of Campylobacter spp. in faecal samples was higher among crows (39.2 %) than pigeons (30.0 %), (P < 0.05). Campylobacter jejuni was the most common species detected among wild bird faecal samples (98.2 %). Meanwhile, Campylobacter coli prevalence in wild bird faecal samples was low-6 %. The Simpson's diversity index of C. jejuni flaA RFLP types was lower in pigeons (D = 0.88) compared with C. jejuni isolates detected in crows (D = 0.97). Obtained results revealed that C. jejuni are widely prevalent among crows and pigeons, indicating these wild birds as potential infection sources to humans. Further studies are required to determine crows and pigeons role in zoonotic transmission of Campylobacter.

Molecular Epidemiology of Novel Pathogen "Brachyspira hampsonii" Reveals Relationships between Diverse Genetic Groups, Regions, Host Species, and Other Pathogenic and Commensal Brachyspira Species

Outbreaks of bloody diarrhea in swine herds in the late 2000s signaled the reemergence of an economically significant disease, swine dysentery, in the United States. Investigations confirmed the emergence of a novel spirochete in swine, provisionally designated "Brachyspira hampsonii," with two genetically distinct clades. Although it has since been detected in swine and migratory birds in Europe and North America, little is known about its genetic diversity or its relationships with other Brachyspira species. This study characterizes B. hampsonii using a newly developed multilocus sequence typing (MLST) approach and elucidates the diversity, distribution, population structure, and genetic relationships of this pathogen from diverse epidemiological sources globally. Genetic characterization of 81 B. hampsonii isolates, originating from six countries, with our newly established MLST scheme identified a total of 20 sequence types (STs) belonging to three clonal complexes (CCs). B. hampsonii showed a heterogeneous population structure with evidence of microevolution locally in swine production systems, while its clustering patterns showed associations with its epidemiological origins (country, swine production system, and host species). The close genetic relatedness of B. hampsonii isolates from different countries and host species highlights the importance of strict biosecurity control measures. A comparative analysis of 430 isolates representing seven Brachyspira species (pathogens and commensals) from 19 countries and 10 host species depicted clustering by microbial species. It revealed the close genetic relatedness of B. hampsonii with commensal Brachyspira species and also provided support for the two clades of B. hampsonii to be considered a single species.

Global Epidemiology of Campylobacter Infection

Campylobacter jejuni infection is one of the most widespread infectious diseases of the last century. The incidence and prevalence of campylobacteriosis have increased in both developed and developing countries over the last 10 years. The dramatic increase in North America, Europe, and Australia is alarming, and data from parts of Africa, Asia, and the Middle East indicate that campylobacteriosis is endemic in these areas, especially in children. In addition to C. jejuni, there is increasing recognition of the clinical importance of emerging Campylobacter species, including Campylobacter concisus and Campylobacter ureolyticus. Poultry is a major reservoir and source of transmission of campylobacteriosis to humans. Other risk factors include consumption of animal products and water, contact with animals, and international travel. Strategic implementation of multifaceted biocontrol measures to reduce the transmission of this group of pathogens is paramount for public health. Overall, campylobacteriosis is still one of the most important infectious diseases that is likely to challenge global health in the years to come. This review provides a comprehensive overview of the global epidemiology, transmission, and clinical relevance of Campylobacter infection.

Virulence genes, antibiotic resistance and integrons in Escherichia coli strains isolated from synanthropic birds from Spain

The aim of this study was to determine the presence of virulence genes and antibiotic resistance profiles in 164 Escherichia coli strains isolated from birds (feral pigeons, hybrid ducks, house sparrows and spotless starlings) inhabiting urban and rural environments. A total of eight atypical enteropathogenic E. coli strains were identified: one in a house sparrow, four in feral pigeons and three in spotless starlings. Antibiotic resistance was present in 32.9% (54) of E. coli strains. The dominant type of resistance was to tetracycline (21.3%), ampicillin (19.5%) and sulfamethoxazole (18.9%). Five isolates had class 1 integrons containing gene cassettes encoding for dihydrofolate reductase A (dfrA) and aminoglycoside adenyltransferase A (aadA), one in a feral pigeon and four in spotless starlings. To our knowledge, the present study constitutes the first detection of virulence genes from E. coli in spotless starlings and house sparrows, and is also the first identification worldwide of integrons containing antibiotic resistance gene cassettes in E. coli strains from spotless starlings and pigeons.

PESQUISA DE SALMONELLA EM MUTUNS (Mitu mitu) MANTIDOS EM CATIVEIRO

Foram colhidas 50 amostras de fezes de mutuns do Criadouro Científico e Cultural Poços de Caldas. A amostras foram enriquecidas em meio caldo Tetrationato e Selenito-Cistina e plaqueadas em Salmonella Shigella (SS), Mac Conkey (MC), Endo-C (EC), Verde Brilhante (VB) e Eosina Azul de Metileno (EMB), a 37º C por 24h. Colônias suspeitas de Salmonella spp foram inoculadas em tubos contendo Ágar Tríplice Açúcar Ferro (TSI) e incubadas a 37 ºC por 24 h. Os tubos com crescimento característico foram submetidas ao teste de aglutinação em lâmina com soros polivalentes somático e flagelar. Os meios SS, MC e VB foram os mais eficientes para o cultivo, sendo 6% das amostras, positivas para Salmonella spp. Sabendo-se que as aves são reservatórios importantes de spp e que esta pode representar um alto risco para a saúde humana, há a necessidade de implantação de uma rotina de limpeza dos recintos para evitar contaminação entre os recintos e o consequente carreamento destes micro-organismos, pelos tratadores, até suas residências ou outros recintos. A presença da Salmonella spp em criadouros pode ser responsável pela menor eclodibilidade dos ovos, prejudicando o objetivo da entidade, que visa o estudo e a manutenção das diferentes espécies de aves silvestres.

O pombo (Columba livia) como agente carreador de Salmonella spp. e as implicações em saúde pública

Os pombos domésticos e silvestres estão distribuídos por todo o mundo e carreiam micro-organismos patogênicos ao homem e a outros animais, podendo ser um dos responsáveis pela disseminação de Salmonella spp. Este patógeno gera grande preocupação para a economia mundial, uma vez que cria transtornos para a indústria avícola quando ocorre contaminação dos plantéis e ônus para a saúde pública devido a surtos de infecção alimentar causados por esta bactéria. Dessa forma, objetivou-se realizar um levantamento acerca da participação do pombo doméstico na possível disseminação de Salmonella spp.

First identification of "Brachyspira hampsonii" in wild European waterfowl

Anseriformes deserve special attention in the epidemiology of Brachyspira spp. because diverse Anseriformes species have been described to act as highly efficient carriers of several Brachyspira spp. that can also infect livestock. The aim of this study was to investigate the prevalence and diversity of Brachyspira spp. in waterfowl that winter in Spain. Brachyspira spp. were isolated from 51 of the 205 faecal samples collected from graylag geese and mallards in the Villafáfila Lagoons Nature Reserve (Northwestern Spain). The Brachyspira species identified through phenotyping, PCR and sequencing of the nox gene were B. pilosicoli (5.9%), B. alvinipulli (11.8%), "B. hampsonii" (19.6%), B. murdochii (23.5%) and B. innocens (39.2%). The most relevant finding of this study is the description of "B. hampsonii" in specimens from birds for the first time. Phylogenetic analysis of the nox gene sequences grouped all of the obtained "B. hampsonii" isolates into a cluster with Brachyspira strains previously identified by others as "B. hampsonii" and separated from other Brachyspira spp. isolates and reference strains. Additionally, this cluster was related to clades that grouped B. murdochii and B. innocens isolates. The identification of "B. hampsonii" was also achieved in 8 of the 10 isolates by sequencing the16S rRNA gene and tlyA gene. Regardless of the species identified, no antimicrobial resistance was observed in any of the enteropathogenic isolates recovered. This is the first description of "B. hampsonii" in European waterfowl, which might represent hosts that serve as natural reservoirs of this Brachyspira species. This finding indicates that this spirochete is not limited to North America, and its presence in wild birds in Europe poses a risk of transmission to livestock.

Use of observed wild bird activity on poultry farms and a literature review to target species as high priority for avian influenza testing in 2 regions of Canada

The risk of avian influenza outbreaks in poultry is partially dependent on the probability of contact between domestic poultry and wild birds shedding avian influenza (AI) virus. The major objective of this study was to document wild bird activity on poultry farms to determine which wild bird species should be targeted for AI surveillance in Canada. We collected data in 2 major poultry producing regions of Canada, southwestern Ontario and the Fraser Valley of British Columbia, on the relative abundance of various wild bird species found on poultry farms and on how these species utilized habitat around poultry farms. We reviewed the published literature to determine what was known about AI pathobiology in the species we observed. From these results we created a list of 10 wild bird species that are a priority for further study. These species are the European starling, barn swallow, rock dove, American crow, northwestern crow, American robin, dark-eyed junco, song sparrow, horned lark, and common grackle. Abundance of these and other species varied between provinces and seasons.

Influenza A virus monitoring in urban and free-ranging pigeon populations in Germany, 2006-2008

Tracheal and cloacal swabs as well as blood samples from 408 feral urban (Columba livia forma domestica) and 170 free-ranging wood pigeons (Columba palumbus) in Germany were tested for infection with avian influenza viruses (AIVs). Neither influenza A virus was isolated in the swab samples nor influenza A virus RNA detected using real-time reverse transcriptase-PCR (RT-qPCR). In three urban feral pigeons, avian paramyxovirus (APMV) serotype 1 was isolated. Two of 123 serum samples from hunted free-ranging wood pigeons contained specific antibodies against influenza A virus but not against the subtypes H5 and H7. In conclusion, our study indicates that even after the occurrence of zoonotic highly pathogenic avian influenza virus (HPAIV) subtype H5N1 in the area of investigation in Germany, pigeons do not play a major part in the transmission of influenza viruses. The risk of AIV infection for humans from urban and free-ranging wood pigeons is, if at all, of minimal importance.

Screening of feral and wood pigeons for viruses harbouring a conserved mobile viral element: characterization of novel Astroviruses and Picornaviruses

A highly conserved RNA-motif of yet unknown function, called stem-loop-2-like motif (s2m), has been identified in the 3′ end of the genomes of viruses belonging to different RNA virus families which infect a broad range of mammal and bird species, including Astroviridae, Picornaviridae, Coronaviridae and Caliciviridae. Since s2m is such an extremely conserved motif, it is an ideal target for screening for viruses harbouring it. In this study, we have detected and characterized novel viruses harbouring this motif in pigeons by using a s2m-specific amplification. 84% and 67% of the samples from feral pigeons and wood pigeons, respectively, were found to contain a virus harbouring s2m. Four novel viruses were identified and characterized. Two of the new viruses belong to the genus Avastrovirus in the Astroviridae family. We propose two novel species to be included in this genus, Feral pigeon astrovirus and Wood pigeon astrovirus. Two other novel viruses, Pigeon picornavirus A and Pigeon picornavirus B, belong to the Picornaviridae family, presumably to the genus Sapelovirus. Both of the novel picornaviruses harboured two adjacent s2m, called (s2m)₂, suggesting a possible increased functional effect of s2m when present in two copies.

Screening for several potential pathogens in feral pigeons (Columba livia) in Madrid

Background

Pathogens with the zoonotic potential to infect humans, such as Campylobacter jejuni, Campylobacter coli and Chlamydophila psittaci, can be found in feral pigeons (Columba livia). Given the high density of these birds in the public parks and gardens of most cities, they may pose a direct threat to public health.

Methods

A total of 118 pigeons were captured in three samplings carried out in 2006-2007 in public parks and gardens in Madrid, Spain. Standard haematological and morphological analyses were carried out on the pigeons. PCR was used to screen for the presence of Campylobacter jejuni, C. coli and Chlamydophila psittaci. Positive samples were confirmed by DNA sequencing.

Results

The analyses demonstrated a high prevalence of Chlamydophila psittaci (52.6%) and Campylobacter jejuni (69.1%) among the birds captured. In contrast, Campylobacter coli was rarely detected (1.1%).

Conclusions

Pigeons in Madrid can carry Chlamydophila psittaci and Campylobacter jejuni. They may be asymptomatic or subclinical carriers of both pathogens.

Diarrheagenic Escherichia coli strains recovered from urban pigeons (Columba livia) in Brazil and their antimicrobial susceptibility patterns

Urban pigeons (Columba livia) come into close contact with humans and animals, and may contribute to the spread of infectious agents. These may include human pathogens such as diarrheagenic Escherichia coli strains, which are able to survive in pigeon feces, thus creating potential for human exposure and infection. Our objectives were to determine the occurrence of diarrheagenic E. coli strains in fresh feces from urban pigeons and their drug susceptibility patterns. E. coli strains were isolated from 100 fresh feces samples and presumptive phenotypic species identification was carried out, confirmed by amplification of specific 16S ribosomal RNA encoding DNA. Multiplex PCR was performed to characterize pathogenic strains. Drug susceptibility patterns were determined by the agar dilution method. Enteroinvasive E. coli, Shiga toxin-producing E. coli, enteropathogenic E. coli, and enterotoxigenic E. coli were detected at an overall rate of 12.1%. Among the isolated E. coli strains, 62.1% were susceptible to all tested drugs, whereas 37.9% were resistant to at least one of the antimicrobials tested. Amikacin was the less effective drug (36.8% resistance), followed by ampicillin (7.8%). No resistance was detected to gentamicin, ceftriaxone, and ceftazidime and almost all the isolates were susceptible to ampicillin-sulbactam (98.4%), levofloxacin (97.8%), and trimethoprim-sulfamethoxazole (96.1%). Since these pigeons may harbor multidrug-resistant pathogens, their presence in an urban environment could be an important component of infection spread, with impact on public health.

Comparison of Campylobacter populations in wild geese with those in starlings and free-range poultry on the same farm

Wild geese are a potential source of Campylobacter infection for humans and farm animals and have been implicated in at least two large waterborne disease outbreaks. There have been few investigations into the population biology of Campylobacter in geese, carriage rates are reported to vary (0 to 100%), and no genetic characterization of isolates has been performed. Fecal samples collected from wild geese in Oxfordshire, United Kingdom, were culture positive for C. jejuni (50.2%) and C. coli (0.3%). The C. jejuni (n = 166) isolates were characterized by using multilocus sequence typing and were compared with isolates collected from free-range broiler chickens and wild starlings sampled at the same location. A total of 38 STs, six clonal complexes, and 23 flaA SVR nucleotide STs were identified. The ST-21 and ST-45 complexes (5.4% of isolates) were the only complexes to be identified among isolates from the geese and the other bird species sampled in the same location. These clonal complexes were also identified among human disease isolates collected in the same health care region. The results indicate that large numbers of wild geese carry Campylobacter; however, there was limited mixing of Campylobacter populations among the different sources examined, and the host source could be predicted with high probability from the allelic profile of a C. jejuni isolate. In conclusion, genotypes of C. jejuni isolated from geese are highly host specific, and a comparison with isolates from Oxfordshire cases of human disease revealed that while geese cannot be excluded as a source of infection for humans and farm animals, their contribution is likely to be minor.

Susceptibility and transmissibility of pigeons to Asian lineage highly pathogenic avian influenza virus subtype H5N1

To determine whether or not pigeons are susceptible to infection with Asian lineage highly pathogenic (HP) avian influenza virus (AIV) subtype H5N1 and can serve as a transmission host for H5N1 HPAIV, we experimentally infected 187 young and adult pigeons with five different isolates of H5N1 HPAIV and co-habited some experimentally infected pigeons with susceptible specific pathogen free chickens. Results showed that all infected pigeons remained clinically healthy during the observation period. No gross lesions or histopathological changes were observed in the infected pigeons, and haemagglutination inhibition antibodies were not detected in serum samples of the infected pigeons. Additionally, all chickens placed in contact with AIV H5N1 infected pigeons remained healthy, and no virus or haemagglutination inhibition antibodies were detected in samples from the chickens. Our data suggest that pigeons are not susceptible to Asian lineage H5N1 HPAIV and do not transmit the virus to chickens.

Avian influenza virus screening in wild waterfowl in Norway, 2005

The prevalence of influenza A virus infection, and the distribution of different subtypes of the virus, were studied in 604 geese and ducks shot during ordinary hunting 2005. The study was based upon molecular screening of cloacal swabs taken by the hunters. The sampling included the following species: greylag (Anser anser), mallard (Anas platyrhynchos), wigeon (Anas penelope), teal (Anas crecca), goosander (Mergus merganser), tufted duck (Aythya fuligula), common scoter (Melanitta nigra), goldeneye (Bucephala clangula), and red-breasted merganser (Mergus serrator). The samples found to be positive in the initial pan-influenza A virus reverse transcription-polymerase chain reaction (RT-PCR) were further subtyped by using a specific H5 RT-PCR and full-length RT-PCRs for the hemagglutinin (HA) and neuraminidase genes. None of the greylag samples (0/185) were positive for influenza Avirus, whereas 19.1% of the ducks (80/419) were positive. The prevalences of influenza A virus in the different duck species were as follows: mallard, 20.4% (58/284); wigeon, 12.5% (8/64); teal, 30.9% (13/42); goosander, 0% (0/5); tufted duck, 0% (0/4); common scoter, 14.3% (1/7); goldeneye, 0% (0/11); and red-breasted merganser, 0% (0/2). H5N1 subtype was found in one mallard and H5N2 subtype in another mallard and one teal. Sequencing of the HA gene identified all three viruses as low-pathogenic strains, closely related to low-pathogenic H5 influenza A viruses evidenced in recent years in Sweden and the Netherlands. The other subtypes identified included H1N1, H2, H3N2, H3N8, H6N1, H6N2, H6N8, H8N4, H9N2, H11N9, and H12 in mallards; H3N2, H6N2, H6N8, and H9N2 in teals; and H6N2 in wigeons and common scoter.