Salmonella Surveillance Among Great-Tailed Grackles (Quiscalus mexicanus) and Other Urban Bird Species in Eastern Texas

Ciprofloxacin-resistant ST198 Salmonella Kentucky in a hospitalized American black bear (Ursus americanus), with evidence of subsequent nosocomial transmission

Global emergence of ciprofloxacin-resistant ST198 Salmonella Kentucky poses an important public health threat. While conducting Salmonella surveillance among wildlife patients admitted to our veterinary medical teaching hospital in central New York, we isolated multidrug-resistant (MDR) ST198 Salmonella Kentucky from an American black bear (Ursus americanus) in September 2020. The isolate was phenotypically resistant to numerous antimicrobial agents, including ceftriaxone and ciprofloxacin, and several antimicrobial resistance genes and mutational resistance determinants were detected. Between April and July 2021, the same strain of MDR ST198 Salmonella Kentucky was also isolated from seven other wildlife patients and multiple hospital environmental locations, suggesting nosocomial transmission. Ciprofloxacin resistance is conferred by triple point mutations in the quinolone resistance-determining regions (QRDRs), a genotypic profile indicative of Clade ST198.2. To our knowledge, this is the first report of this ciprofloxacin-resistant clade being identified in animals or animal products in the United States. Timely resolution of the outbreak was achieved following efforts to further enhance environmental disinfection protocols and biosecurity measures at the hospital, with no known cases or positive environmental samples after July 2021.

Indicators for climate change-driven urban health impact assessment

Climate change can cause multiply potential health issues in urban areas, which is the most susceptible environment in terms of the presently increasing climate volatility. Urban greening strategies make an important part of the adaptation strategies which can ameliorate the negative impacts of climate change. It was aimed to study the potential impacts of different kinds of greenings against the adverse effects of climate change, including waterborne, vector-borne diseases, heat-related mortality, and surface ozone concentration in a medium-sized Hungarian city. As greening strategies, large and pocket parks were considered, based on our novel location identifier algorithm for climate risk minimization. A method based on publicly available data sources including satellite pictures, climate scenarios and urban macrostructure has been developed to evaluate the health-related indicator patterns in cities. The modelled future- and current patterns of the indicators have been compared. The results can help the understanding of the possible future state of the studied indicators and the development of adequate greening strategies. Another outcome of the study is that it is not the type of health indicator but its climate sensitivity that determines the extent to which it responds to temperature rises and how effective greening strategies are in addressing the expected problem posed by the factor.

SALMONELLA ISOLATED FROM CENTRAL NEW YORK WILDLIFE ADMITTED TO A VETERINARY MEDICAL TEACHING HOSPITAL

The role of wildlife as a source of zoonotic Salmonella transmission is poorly understood, as are the clinical implications of this pathogen among wildlife species. Wildlife hospitals represent an important location to conduct Salmonella surveillance, given the wide variety of species admitted for medical and surgical care. Our objectives were to estimate the prevalence of fecal Salmonella shedding among wildlife admitted to a veterinary medical teaching hospital, to identify risk factors for infection, and to fully characterize the isolates. Voided fecal samples (birds and mammals) and cloacal swab samples (reptiles and amphibians) were collected between May 2018 and March 2020. Standard bacteriologic culture methods were used to detect Salmonella, and isolates were characterized via serotyping, antimicrobial susceptibility testing, and whole-genome sequencing. Samples were collected from 348 wildlife patients representing 74 wildlife species, and the apparent prevalence of fecal Salmonella shedding was 1.4% (5/348; 95% confidence interval, 0.5-3.3%). Four serotypes were identified, and isolates were phenotypically susceptible to all antimicrobial agents tested. Two isolates were closely related to human clinical isolates, demonstrating the overlap between wildlife and human pathogens. Fecal Salmonella shedding among hospitalized wildlife appears to be uncommon, and the risk of either nosocomial or zoonotic Salmonella transmission is presumably low. Nevertheless, the occurrence of Salmonella in wildlife, particularly among common species found in a wide array of habitats, poses a potential threat to public health and may result in transmission to more-vulnerable wildlife populations.

Vector-Borne Blood Parasites of the Great-Tailed Grackle (Quiscalus mexicanus) in East-Central Texas, USA

Great-tailed grackles (Quiscalus mexicanus) have dramatically expanded into North America over the past century. However, little is known about the blood that parasites they support. Here, for the first time, we document an assemblage of trypanosome, haemosporida, and filarial nematodes co-circulating in invasive great-tailed grackles. Between February and July, 2015, 61 individuals were captured in an urban environment of College Station, Texas. Field microscopy and molecular diagnostics indicate that 52% (24/46) were visually infected with filarioid nematodes, 24% (11/46) with avian trypanosomes, and 73% (n = 44/60) with haemosporida parasites, such as Haemoproteus (Parahaemoproteus) and Plasmodium cathemerium. Overall, 87% of great-tailed grackles were infected with blood parasites. Although 50% of individuals hosted parasites from multiple phylum, no patterns of parasite assembly were observed. Results indicate that great-tailed grackles can support a relatively high level of blood parasitism. However, the consequences for avian health remain to be determined.

European Starlings (Sturnus vulgaris) as Vectors and Reservoirs of Pathogens Affecting Humans and Domestic Livestock

European starlings are an abundant, widespread avian species frequently found in close association with human development and agriculture. The ability of starlings to carry and disperse pathogens of humans and domesticated livestock has received considerable attention, including studies of enteric bacteria, viruses, and some fungi. To investigate the importance of European starlings as disease vectors, I reviewed and assessed the available literature, comprising several hundred published papers. Although a wide variety of potential pathogens have been reported in starlings, the strongest evidence suggests that they may be responsible for harboring and dispersing some species of enteric bacteria, with Escherichia coli and Campylobacter jejuni of perhaps greatest interest, and primarily in the context of dairies, concentrated animal feeding operations, and other intensive livestock agriculture.

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.

A review of Salmonella enterica with particular focus on the pathogenicity and virulence factors, host specificity and antimicrobial resistance including multidrug resistance

Salmonella genus represents the most common foodborne pathogens frequently isolated from food-producing animals that is responsible for zoonotic infections in humans and animal species including birds. Thus, Salmonella infections represent a major concern to public health, animals, and food industry worldwide. Salmonella enterica represents the most pathogenic specie and includes > 2600 serovars characterized thus far. Salmonella can be transmitted to humans along the farm-to-fork continuum, commonly through contaminated foods of animal origin, namely poultry and poultry-related products (eggs), pork, fish etc. Some Salmonella serovars are restricted to one specific host commonly referred to as "host-restricted" whereas others have broad host spectrum known as "host-adapted" serovars. For Salmonella to colonize its hosts through invading, attaching, and bypassing the host's intestinal defense mechanisms such as the gastric acid, many virulence markers and determinants have been demonstrated to play crucial role in its pathogenesis; and these factors included flagella, capsule, plasmids, adhesion systems, and type 3 secretion systems encoded on the Salmonella pathogenicity island (SPI)-1 and SPI-2, and other SPIs. The epidemiologically important non-typhoidal Salmonella (NTS) serovars linked with a high burden of foodborne Salmonella outbreaks in humans worldwide included Typhimurium, Enteritidis, Heidelberg, and Newport. The increased number of NTS cases reported through surveillance in recent years from the United States, Europe and low- and middle-income countries of the world suggested that the control programs targeted at reducing the contamination of food animals along the food chain have largely not been successful. Furthermore, the emergence of several clones of Salmonella resistant to multiple antimicrobials worldwide underscores a significant food safety hazard. In this review, we discussed on the historical background, nomenclature and taxonomy, morphological features, physical and biochemical characteristics of NTS with a particular focus on the pathogenicity and virulence factors, host specificity, transmission, and antimicrobial resistance including multidrug resistance and its surveillance.

Prevalence of Trichomonas, Salmonella, and Listeria in Wild Birds from Southeast Texas

Infectious diseases can be a major threat to wildlife populations, especially in human-modified habitats, but infection rates in populations of wild animals are often poorly studied. Trichomonas, Salmonella, and Listeria are all pathogens known to infect birds, but their infection rates in wild bird populations are not well documented. This study documents infection rates of the three pathogens in wild bird populations inhabiting a suburban to rural gradient in Southeast Texas. Various species of wild birds were sampled at five sites in Southeastern Texas representing rural (<1 house per ha), exurban (approximately 1 house per ha), and suburban (approximately 10 houses per ha) habitat types. Birds were captured in mist nets and samples were taken from the oral cavity, crop, and vent to detect the presence of pathogens. Samples were screened for Trichomonas by examining wet mounts under a light microscope, whereas samples were screened for Salmonella and Listeria by examining colonies grown on agar plates. Pathogens detected during the initial screening were further confirmed by PCR and DNA sequencing. Infection rates for Trichomonas, Salmonella, and Listeria were 9%, 17%, and 5%, respectively. The distributions of infection rates across habitats (i.e., rural, exurban, rural) did not differ significantly from the expected null distributions for any of the three pathogens; however, the data suggested some interesting patterns that should be confirmed with a larger dataset. Infection rates for Trichomonas and Salmonella were highest at the suburban sites, whereas the infection rate for Listeria was highest at the rural site. Feeder birds were more likely to be infected by all three pathogens than non-feeder birds. Small sample sizes prevent definitive conclusions regarding variation in infection rates along the suburban to rural gradient, but the results suggest that pathogens followed the predicted patterns. For many of the bird species sampled, this study presents the first report of infection rates by these three pathogens in wild populations.

Investigation of potential risk factors associated with Salmonella presence in commercial laying hen farms in Nigeria

BACKGROUND

In 2012/13, the Federal government of Nigeria approved the surveillance of salmonellae in commercial poultry farms with the aim of generating baseline data for the development of a control programme. That baseline provided an opportunity to investigate potential risk factors in commercial layer farms.

METHODS

Five hundred and twenty-three farms were evaluated for the presence of Salmonella. Each farmer was interviewed through a structured questionnaire. Univariate analysis identified 26 variables potentially associated with Salmonella presence on the farms, with different levels of significance. To simultaneously evaluate the effect of these variables, a multivariable logistic regression model was implemented.

RESULTS

Farmers that are member of the Poultry Association of Nigeria (PAN) emerged as a risk factor, as well as being farmer as exclusive occupation. The risk of Salmonella increased in farms with a combined housing system as compared to farms with a single housing system. Moreover, in terms of farm management the use of plastic egg crates had a higher risk of Salmonella presence compared to paper crates. Higher risk of contamination was also identified in farms having regular contact with animal health workers, since this could be indicative of animal health problems requiring continuous assistance. Farms with no previous outbreak of salmonellosis were associated with an increase risk, since most of the farms in this category were newly established. With regard to feeding, the use of coccidiostats and commercial feeds were associated with the spread of Salmonella. Unexpectedly, the presence of other farms at distances further than 1 km away was associated with an increase in Salmonella presence as compared to farms which were in closer proximity. Close proximity among farms could favour the application of stricter biosecurity measures.

CONCLUSIONS

The results of the survey can be considered a baseline for implementing effective measures aimed at reducing the Salmonella prevalence in Nigerian laying hen farms.

Importance of Wild Species Kept in Captivity as Reservoirs of Salmonella Serotypes for Human in Petting Exhibitions and Zoo in Iran with Focus on Antimicrobial Resistance

Salmonella spp. is the leading cause of zoonotic enteric diseases wich represents a public health concern worldwide. The incidence of zoo-associated salmonellosis is rather high due to the high prevalence and shedding of this bacterium from wild animals specially kept in stressful conditions. To determine the potential public health risk presented by zoo animals in Semnan, we investigated the prevalence of Salmonella serovars Enteritidis and Typhimurium among wild animal species kept in the zoo and pet shops. Totally, 152 fecal samples from species in the zoo and pet shops were collected and Salmonella prevalence and identification was assessed via standard bacteriologic culture methods, serotyping, multiplex-PCR and antimicrobial susceptibility testing. Overall, 21% (32/152) of the samples were confirmed positive for Salmonella and serotyping showed 12.5% (19/32) Salmonella serovar Enteritidis and 8.5% (13/32) serovar Typhimurium, respectively. All the Salmonella isolates were sensitive to Chloramphenicole, Flurefenicole, Meropenem, Ceftizoxime, Imipenem and Ampicillin, while resistance was observed in the case of Nalidixic acid (78%) as the highest resistance, Streptomycin (28%), Oxytetracycline, Neomycin, Furazolidone (each one 15%) and Lincospectin (9.3%). The high occurrence of multidrug resistance Salmonella in zoo and pet animals represents a potential threat to public health and requires strict surveillance and application of hygienic criteria.

Prevalence of Salmonella among waterfowl along the Texas Gulf coast

Migratory waterfowl may play a role in the ecology and transmission of zoonotic pathogens, given their ability to travel long distances and their use of varied habitats. Our objectives were to estimate the prevalence of Salmonella among waterfowl along the Texas Gulf coast and to characterize the isolates. Faecal samples were collected from hunter-harvested waterfowl at four wildlife management areas from September through November, 2016. Standard bacteriologic culture methods were used to isolate Salmonella from samples, and isolates were characterized by serotyping and anti-microbial susceptibility testing. The apparent prevalence of faecal Salmonella shedding was 0.5% (2/375). Serotypes identified were Thompson and Braenderup, and both isolates were susceptible to all anti-microbial agents tested. Although faecal contamination of agricultural fields or surface waters could serve as a potential source of zoonotic Salmonella transmission, waterfowl along the Gulf coast during the fall hunting season appear to pose minimal risk.