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Development of a multivalent adjuvanted inactivated vaccine against variant arthrotropic avian reoviruses
No full textVariant avian reoviruses (ARVs) are economically important emerging pathogens of poultry, which mainly affect young broiler chickens and cause significant production losses. Currently, there are no effective commercial vaccines available for control and prevention of emerging variant ARVs. In this study, monovalent inactivated adjuvated (20% Emulsigen D) broiler breeder vaccines containing antigens from ARV genotype cluster (C) group -2, -4, -5, or -6, and a multivalent vaccine containing antigens from all the four indicated genotypic cluster groups were developed and evaluated for their efficacy in protecting broiler progenies against homologous or heterologous ARV challenge. The use of monovalent or multivalent inactivated vaccines in a prime-boost immunization strategy induced the production of ARV specific antibodies in broiler breeders. The maternal antibodies were effectively transferred to broiler progenies. Broiler progenies obtained from immunized breeders demonstrated milder clinical symptoms and reduced gross and histopathological lesions after homologous ARV challenge. More severe gross and histological lesions were observed in challenged progenies from unvaccinated broiler breeders. However, cross protection was not observed when either of the monovalent-vaccine groups were challenged with a heterologous virus. In addition, the progenies from the unvaccinated ARV challenged control or heterologous ARV challenged vaccinated groups had significantly reduced body weight gain (p < 0.01) than the unchallenged-control, challenged-multivalent, or homologous ARV-challenged monovalent vaccine groups. However, homologous ARV challenged progenies in the multivalent or monovalent vaccine groups had similar body weight gain as the control unchallenged group with significantly reduced viral load (p < 0.01) in the gastrocnemius tendon tissue. This study indicates that broad-spectrum protection of broiler progenies from variant ARV infections is feasible through the development of multivalent vaccines after proper characterization, selection and incorporation of multiple antigens based on circulating ARV genotypes in targeted regions.Chicken Farmers of SaskatchewanNatural Sciences and Engineering Research Council of CanadaSaskatchewan Agriculture Development Fun
Facile deoxygenative reduction of a bridging carbonato ligand with Silyl and Boryl 4,4’‐Bipyridinylidene reagents
No full textThe reactivity of CO2 with a previously described PCcarbeneP cobalt(I) hydroxide is reported. Insertion of CO2 into the Co−OH bond followed by a dehydration reaction releasing water results in a cobalt(I) bridging carbonate species featuring fluctional κ1: κ1 and κ1: κ2 coordination of the central carbonate moiety. The reduction chemistry of the resulting cobalt(I) bridging carbonate species is explored utilizing deoxygenative reducing agents N,N′-bis(trimethylsilyl)- and N,N′-bis(pinacolatoboryl)-4,4′-bipyridinylidene. The three-electron reduction produces the corresponding PCcarbeneP cobalt(I) siloxide or boroxide complex alongside a PCcarbeneP cobalt(0) monocarbonyl, silyl/boryl ether, and 4,4’-bipyridine
Cooperative nitrile coordination using nickel and a boron‐containing secondary coordination sphere**
No full textMetal-ligand cooperation has emerged as a versatile tool for substrate activation in chemical reactivity. Herein, we provide the synthesis and characterization of a monoboranyl-containing analogue of the ubiquitous bulky diphosphine ligand, 1,2-bis(di-tert-butylphosphino)ethane, whose reactivity has been examined using nickel. Together, the pairing of nickel and boron provides a platform that allows for the cooperative coordination of organonitriles, giving unusual examples of intermolecularly bound dinickelacycles
Nodular gill disease in Northeastern Italy: An investigation on the prevalence of the disease and the risks of introduction in rainbow trout farms
No full textNodular Gill Disease (NGD) is an emerging pathogenic condition that causes gill damage and mainly affects farmed freshwater fish, rainbow trout (Oncorhynchus mykiss) in particular, and this inevitably generates noticeable economic losses for the industry. The present study aimed to assess the prevalence of NGD in the Autonomous Province of Trento, a highly productive area located in Northeastern Italy, traditionally suited to rainbow trout production, and to identify possible risk factors for the introduction of this disease in trout farms. The necessary data were obtained through a questionnaire and the collection of fish samples. According to the data analysis, 42% of the investigated farms tested positive for NGD. The two possible risk factors identified for its introduction in farms are the presence of other diseases in the same farm (OR = 17.5; 95% CI = 2.7; 111.5) and having farms located 5 km upstream (OR = 24.8; 95% CI = 2.9; 211.1). These results highlight (i) a possible impairment of the immune system caused by other diseases as a predisposing factor to the manifestation of the pathology and (ii) the role of water in spreading pathogens
Antimicrobial use and its association with the isolation of and antimicrobial resistance in Campylobacter spp. recovered from fecal samples from Canadian dairy herds: A cross-sectional study
No full textCampylobacteriosis is one of the most common zoonotic diseases in North America. As opposed to humans, animal infections caused by Campylobacter spp. are often asymptomatic. In this study, data collected through the Canadian Dairy Network for Antimicrobial Stewardship surveillance system were used to determine the proportion of Campylobacter spp. and antimicrobial resistant isolates recovered from dairy cattle herds. Additionally, the association of antimicrobial use (AMU) with fecal carriage and antimicrobial resistance (AMR) of Campylobacter spp. were investigated. Pooled fecal samples from 5 animals from each production phase (pre-weaned calves, post-weaned heifers, lactating cows), and a manure storage sample were collected from 140 dairy herds across Canada. Samples were cultured using selective media, and Campylobacter isolates were speciated using matrix-assisted laser desorption/ionization-time of flight mass spectrometry. Antimicrobial susceptibilities were determined using the minimum inhibitory concentration test, and interpretation was made according to the Clinical and Laboratory Standards Institute. Two multilevel logistic regression models were used to investigate the association between the AMU with the isolation and antimicrobial resistance in Campylobacter spp. Of 560 samples, 63.8% were positive for Campylobacter spp., and 96% of the participating farms had at least one sample source (i.e., calves, heifers, lactating cows, or manure storage) positive for Campylobacter spp. Overall, 54.3% of the Campylobacter spp. isolates were resistant to at least one antimicrobial. Resistance to tetracycline was observed in 49.7% of the Campylobacter spp. isolates, followed by ciprofloxacin (19.9%) and nalidixic acid (19.3%). The proportion of multi-drug resistant (≥3 antimicrobial classes) Campylobacter spp. isolates was low (0.3%); however, 15.6% were resistant to two different classes of antimicrobials. Samples collected from lactating cows, heifers, and manure storage were more likely to be positive for Campylobacter spp. compared to calves. Total AMU was associated with a decreased probability of recovering Campylobacter spp. In addition, AMR to either tetracycline or ciprofloxacin had an interaction with antimicrobial use. The probability of resistance to tetracycline increased for each unit increase in the total AMU (Defined Course Dose/100 animal-years), while the probability of resistance to ciprofloxacin decreased. Campylobacter coli isolates were more likely to be resistant to ciprofloxacin and tetracycline when compared to C. jejuni. Our study demonstrated that Campylobacter spp. is widespread among Canadian dairy farms, and a higher proportion of resistance to tetracycline was identified. The total AMU was associated with increased resistance to tetracycline in Campylobacter spp. isolates; however, for ciprofloxacin the AMU was associated with decreased resistance
Relationship between quantitative real-time PCR cycle threshold and culture for detection of Streptococcus equi subspecies equi.
No full textObjective To compare PCR and culture results for the detection of Streptococcus equi subspecies equi (S. equi).
Animals Respiratory tract samples (N = 158) from horses being tested for S. equi.
Procedure Bacterial culture was carried out on samples from which S. equi was detected by quantitative real-time PCR.
Results S. equi was isolated from 12 (7.6%) samples: 4/9 (44%) samples when the PCR cycle threshold (CT) was ≤ 30, 7/30 (23%) when the CT was 30.1 to 35, and 1/119 (0.8%) when the CT was 35.1 to 40. The highest CT sample from a sample that yielded a positive culture was 36.9. The optimal Youden’s J value was at a CT of 34.2, the same value as determined by number needed to misdiagnose when the cost of a false negative is deemed to be either 5 or 10 × that of a false positive.
Conclusions Viable S. equi was only detected in a minority of quantitative PCR (qPCR) positive samples. A qPCR CT of 34.2 was a reasonable breakpoint for likelihood of the presence of culturable S. equi.
Clinical relevance Evaluation of CT values may be useful as a proxy to indicate the likelihood of cultivable S. equi being present and could be useful as part of risk assessments.journal article2023 JunimportedEquine Guelp
Field evaluation of a deep learning-based smart variable-rate sprayer for targeted application of agrochemicals
No full textThe field performance of a newly developed novel smart variable-rate sprayer was evaluated. The sprayer uses convolutional neural networks (CNNs) for target detection and spot-applications of agrochemicals within potato (Solanum tuberosum L.) fields attacked by lamb's quarters (Chenopodium album L.) and corn spurry (Spergula arvensis L.) weeds and the early blight potato disease caused by Alternaria solani Sorauer. There was a non-significant effect of treatment conditions (i.e., cloudy, partly cloudy, and sunny) on spray volume during weed and diseased plant detection experiments (p-value = 0.93 and 0.75, respectively) showing that the smart sprayer performed well during all treatment conditions. There was a significant effect of spraying application techniques on the use of spray volume (p-value ≤ 0.05) reflecting a significant saving of spraying liquid during variable-rate application (VA). On average, the sprayer reduced spray volume by 47 and 51% for weeds and diseased plant detection experiments as compared to the values of chemicals applied at constant-rate application (CA), respectively, under all treatment conditions. The analysis of water-sensitive papers (WSP) data resulted in non-significant differences between CA and VA under all field conditions. These results suggest that this sprayer has a great potential to get a suitable spot application of agrochemicals and reduce the use of plant protection products thereby ensuring farm profits and environmental stewardship.Natural Science and Engineering Research Council of Canad
Did the unemployment benefits extension between 2009-2013 deter entrepreneurship in the US? Some evidence and a model of unemployment benefits and entrepreneurship
No full textThe 2007-2008 financial crisis severely dampened the American entrepreneurial sector, and the rate of business formation remained low until 2014. This study empirically assesses whether the extensions of unemployment benefits (EUB) contributed to the delay in recovery in entrepreneurship. We then introduce a general equilibrium occupational choice model of unemployment benefits and entrepreneurship and use sharp discontinuity and variations across states in the maximum duration of benefits at the end of 2013 to identify the negative impact of EUB on startups. Eliminating the EUB increased entrepreneurship by 1.4-1.78 percentage points in 2014. Regarding the model, moderate increases in unemployment benefits primarily affect entrepreneurship through the extensive margin by deterring low-ability and necessity entrepreneurs while having little impact on decisions for high-ability agents; however, overly generous unemployment benefits can negatively impact entrepreneurship, the labor market and the overall economy
Implementation and analysis of an on-farm surveillance system for enteric bacteria in Canadian dairy herds
No full textAntimicrobial resistance (AMR) is an increasing concern for public and animal health as it diminishes the effectiveness of antimicrobials against resistant bacteria and make treatments more difficult and expensive. The research documented in this thesis aimed to describe the development and implementation of CaDNetASR, an on-farm surveillance system focused on collecting data on antimicrobial use (AMU) and AMR in enteric bacteria (E. coli, Campylobacter spp., and non-typhoidal Salmonella serovars) from Canadian dairy farms. The research also included the use of the data collected through CaDNetASR surveillance to describe the phenotypic resistance patterns of E. coli, Campylobacter spp., and Salmonella, and explore the association between AMU and AMR in Canadian dairy herds. The surveillance was implemented in the fall of 2019, and the data were collected yearly from a convenience sample of 144 dairy herds from five different provinces in Canada. Fecal samples from pre-weaned calves, post-weaned heifers, lactating cows, and manure storage were collected. Additionally, herd health, herd management and AMU information were gathered. Fecal samples were cultured for E. coli, Campylobacter spp., and Salmonella. Susceptibility testing on the stored isolates was done using the broth microdilution system method. The proportion of farms positive for Campylobacter spp. was 95.7%, suggesting that these bacteria are widespread among Canadian dairy herds. For Salmonella, the proportion of positive farms was lower ranging from 12% to 17% from 2019 to 2021. No Salmonella Dublin was identified. A higher proportion of resistance to tetracycline than other antimicrobials was observed for all three bacteria. For E. coli a low proportion of resistance was observed to highly important antimicrobials; however, for Campylobacter spp., 19.9% of the isolates were resistant to ciprofloxacin. No resistance was observed to highly important antimicrobials on Salmonella isolates, except for one isolate resistant to amoxicillin/clavulanic acid. The AMU was quantified in Defined Course Dose (DCD - the dose for a standardized complete treatment course on a standard size animal) and converted to a rate indicator - DCD/100 animal-years. The total AMU was split into systemic and intramammary routes of administration to explore the possible differences according to the administration route. Overall, the AMU varied substantially among the dairy farms. Regression models were built to explore the association of AMU and AMR in E. coli and Campylobacter spp. isolates. For Campylobacter spp., only the total AMU was associated with increased resistance to tetracycline. In E. coli, the systemic AMU was associated with increased resistance to nine antimicrobials; however, the intramammary AMU was not significantly associated with resistance. Overall, resistance in dairy farms was low compared to other food-producing animals such as poultry or swine. The findings documented in this thesis provided information that can be used in the future to develop interventions aiming to reduce the use of antimicrobials in dairy farms and promoting more sustainable and responsible husbandry practices
Occurrence and antimicrobial resistance of Salmonella species and potentially pathogenic Escherichia coli in free‐living seals of Canadian Atlantic and eastern Arctic waters
No full textSeal populations in Canadian waters provide sustenance to coastal communities. There is potential for pathogenic and/or antimicrobial-resistant bacteria to transfer to humans through inadvertent faecal contamination of seal products. The objective of this study was to investigate the occurrence and potential antimicrobial resistance of Salmonella spp., Escherichia coli and Listeria monocytogenes in faecal samples collected from grey seals (Halichoerus grypus) in the Gulf of St. Lawrence and from ringed seals (Pusa hispida) in Frobisher Bay and Eclipse Sound, Nunavut, Canada. Grey seals were harvested during commercial hunts or during scientific sampling; ringed seals were collected by Inuit hunters during subsistence harvests. Virulence genes defining pathogenic E. coli were identified by PCR, and antimicrobial susceptibility testing was performed on recovered isolates. In grey seals, E. coli was detected in 34/44 (77%) samples, and pathogenic E. coli (extraintestinal E. coli [ExPEC], enteropathogenic E. coli [EPEC] or ExPEC/EPEC) was detected in 13/44 (29%) samples. Non-susceptibility to beta-lactams and quinolones was observed in isolates from 18 grey seals. In ringed seals from Frobisher Bay, E. coli was detected in 4/45 (9%) samples; neither virulence genes nor antimicrobial resistance was detected in these isolates. In ringed seals from Eclipse Sound, E. coli was detected in 8/50 (16%) samples and pathogenic E. coli (ExPEC and ExPEC/EPEC) in 5/50 (10%) samples. One seal from Eclipse Sound had an E. coli isolate resistant to beta-lactams. A monophasic Salmonella Typhimurium was recovered from 8/50 (16%) seals from Eclipse Sound. All Salmonella isolates were resistant to ampicillin, streptomycin, sulfisoxazole and tetracycline. L. monocytogenes was not detected in any sample. These findings suggest that seals may act as important sentinel species and as reservoirs or vectors for antimicrobial-resistant and virulent E. coli and Salmonella species. Further characterization of these isolates would provide additional insights into the source and spread of antimicrobial resistance and virulence genes in these populations of free-living seals.Ministère de l'Agriculture, des Pêcheries et de l'Alimentation du QuébecGovernment of Nunavut's Department of EnvironmentNunavut Research InstituteIrving Shipbuilding Inc.Fisheries and Oceans Canada's Coastal Environmental Baseline ProgramNunavut Wildlife Management BoardCanadian Wildlife Health Cooperative, Atlantic regio