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Foodborne Pathogen Campylobacter
Get PDFPublication history: Accepted - 3 June 2021; Published online - 8 June 2021
Effect of selective removal of badgers (Meles meles) on ranging behaviour during a ‘Test and Vaccinate or Remove’ intervention in Northern Ireland
Get PDFPublication history: Accepted - 23 April 2021; Published online - 7 May 2021The role of the Eurasian badger (Meles meles) as a wildlife host has complicated the management of bovine tuberculosis (bTB) in cattle. Badger ranging behaviour has previously been found to be altered by culling of badgers and has been suggested to increase the transmission
of bTB either among badgers or between badgers and cattle. In 2014, a five-year bTB intervention research project in a 100 km2 area in Northern Ireland was initiated involving selective removal of dual path platform (DPP) VetTB (immunoassay) test positive badgers and vaccination followed by release of DPP test negative badgers (‘Test and Vaccinate or
Remove’). Home range sizes, based on position data obtained from global positioning system collared badgers, were compared between the first year of the project, where no DPP test positive badgers were removed, and follow-up years 2–4 when DPP test positive badgers were
removed. A total of 105 individual badgers were followed over 21 200 collar tracking nights. Using multivariable analyses, neither annual nor monthly home ranges differed significantly in size between years, suggesting they were not significantly altered by the bTB intervention
that was applied in the study area.This research was funded by the Department of Agriculture, Environment and Rural Affairs for Northern Ireland
Pre-Weaned Calf Rearing on Northern Irish Dairy Farms: Part 1. A Description of Calf Management and Housing Design
Get PDFPublication history: Accepted - 27 June 2021; Pubished online - 30 June 2021.Simple Summary: Calf health, welfare and performance in the first few months of life are important
for the lifetime productivity of dairy cows. Therefore, all aspects of management, including nutrition,
hygiene, housing and health, should be optimal to maintain productive calves. As there is little
information surrounding these areas on Northern Irish dairy farms, this study investigated 66 farms
with the objective of describing common trends and identifying factors which have the potential
to compromise calf health, welfare and performance. A large degree of variation was seen in calf
housing and other management practices across the farms. The majority of housing, in terms of
building design and functionality, was identified as sub-optimal and is likely a contributing factor
for selection of particular management practices. Regular monitoring of management practices
such as measuring quantity of feedstuffs provided and animal live weight allows farmers to assess
the effectiveness of their rearing system. However, this study highlighted a lack of appropriate
monitoring and measuring in several key areas that present a risk for calf health and performance.
Abstract: The first few months of life are of great importance to the longevity and lifetime performance of dairy cows. The nutrition, environment and healthcare management of heifer calves must
be sufficient to minimise exposure to stress and disease and enable them to perform to their genetic
potential. Lack of reporting of farm management practices in Northern Ireland (NI) makes it difficult
to understand where issues impacting health, welfare and performance may occur in the rearing
process. The objective of this study was to investigate housing design and management practices of
calves on 66 dairy farms across NI over a 3-month period and also identify areas that may cause high
risk of poor health and performance in dairy calves. An initial survey was used to detail housing
and management practices, with two subsequent visits to each farm used to collect animal and
housing-based measurements linked to hygiene management, animal health and performance. Large
variations in key elements such as weaning criteria and method, calf grouping method used, nutritional feed plane, and routine hygiene management were identified. The specification of housing,
in particular ventilation and stocking density, was highlighted as a potential limiting factor for calf
health and performance. Lack of measurement of nutritional inputs, hygiene management practices
and calf performance was observed. This poses a risk to farmers’ ability to ensure the effectiveness of
key management strategies and recognise poor calf performance and healthThis research was funded by Department of Agriculture, Environment and Rural Affairs (DAERA) project 17 1 03 with co-funding by Agrisearch
Evaluating macrophytes as indicators of anthropogenic pressures in rivers in Ireland
Get PDFPublication history: Accepted - 6 January 2021; Published online - 10 February 2021.The ability of macrophytes to indicate
pressures in rivers was assessed by comparing metrics
for nitrate (NO3), ammonia (NH4), soluble reactive
phosphorus (SRP), dissolved oxygen saturation (DO),
pH (PH) and siltation (SUBS) with direct estimates of
the pressures at 810 sites in the Republic of Ireland,
supplemented with General Linear Models (GLMs).
The bivariate and rank correlation coefficients using
the full data range and the first and fourth quartiles of
the river pressures varied between 0.22 and - 0.39 for
NO3 and DO; they were smaller or not significant for
the other four metrics. The GLMs provided evidence
for an independent association between NO3 and the
nitrate concentration and SUBS and ammonia,
indicating some specificity for these metrics. Discriminating
sites in the first and fourth quartiles produced
Type II errors between 37 (PH) and 69% (NH4), with a
mean of 50. As the pressure-impact relationships are
not precise enough (low correlation coefficients) that
evidence from a single macrophyte metric is reliable,
combining the metric with evidence from other
biological groups at one site or from three or more
sites may be the most useful approach.Environmental Protection Agency of Ireland - funding of the DETECT Project
(2015-W-LS-9)
Burnley Borough Council - funding to AB
Does agricultural cooperative membership impact technical efficiency of maize production in Nigeria: An analysis correcting for biases from observed and unobserved attributes
Get PDFPublication history: Accepted - 31 December 2020; Published online - 22 January 2021The formation of agricultural cooperatives has been widely promoted as an agricultural development policy initiative to help smallholder farmers cope with multiple production and marketing challenges. Using a nationally representative survey dataset of smallholder maize producers from rural Nigeria, this study assesses the impact of agricultural cooperative membership on technical efficiency (TE). We based our estimation approach on the combination of a newly developed sample selection stochastic production frontier model with propensity score matching to control for possible selectivity biases from both observables and unobservables. We estimate stochastic meta-frontiers to examine TE differences between cooperative members and non-members. Our results reveal that TE levels of members are consistently higher than that of non-members. This calls for continued policy incentives targeted at encouraging farmers to form as well as participate in agricultural cooperatives
Opportunities to reduce nitrous oxide emissions from horticultural production systems in Canada
Get PDFPublication history: Accepted - 26 July 2021; Published - 3 August 2021.Horticultural systems, specifically vegetable production systems, are considered intensive agricultural
systems as they are characterized by high nitrogen (N) fertilizer application rate, frequent tillage, and irrigation
operations. Accordingly, horticultural production in temperate climates is prone to N losses — mainly during
post-harvest (during fall and winter) or pre-plant (spring) periods — such as N2O emissions and nitrate leaching.
The risk for N losses is linked to low crop N use efficiency (NUE) combined with a narrow C:N and high N content
of crop residues. Here we reviewed the studies conducted in Canada and similar climates to better understand the
risk of N2O emission and potential agronomic management strategies to reduce N2O emissions from horticultural
systems. Current knowledge on N2O emissions from horticultural systems indicate that increasing crop NUE,
modifying the amount, type, time, and rate of N fertilizer inputs, and adopting cover crops in crop rotations are
some of the effective approaches to decrease N2O emissions. However, there is uncertainty related to the efficiency
of the existing N2O mitigation strategies due to the complex interactions between the factors (soil characteristics,
type of plant species, climatic conditions, and soil microbial activity) responsible for N2O production from soil.
Little research on N2O emissions from Canadian horticultural systems limits our ability to understand and manage
the soil N2O production processes to mitigate the risk of N2O emissions. Thus, continuing to expand this line of
research will help to advance the sustainability of Canadian horticultural cropping systems.Funding provided by the NSERC CREATE Climate-Smart Soils and Mitacs
Elevate programs
Social Influence of Competing Groups and Leaders in Opinion Dynamics
Get PDFPublication history: Accepted - 11 September 2020; Published online - 19 September 2020.This paper explores the infuence of two competing stubborn agent groups on the
opinion dynamics of normal agents. Computer simulations are used to investigate
the parameter space systematically in order to determine the impact of group size
and extremeness on the dynamics and identify optimal strategies for maximizing
numbers of followers and social infuence. Results show that (a) there are many
cases where a group that is neither too large nor too small and neither too extreme
nor too central achieves the best outcome, (b) stubborn groups can have a moderating, rather than polarizing, efect on the society in a range of circumstances, and (c)
small changes in parameters can lead to transitions from a state where one stubborn
group attracts all the normal agents to a state where the other group does so. We also
explore how these fndings can be interpreted in terms of opinion leaders, truth, and
campaign
A new phylodynamic model of Mycobacterium bovis transmission in a multi-host system uncovers the role of the unobserved reservoir
Get PDFPublication history: Accepted - 25 Aprl 2021; Published online - 25 June 2021.For single host pathogens, pathogen genetic data have been transformative for understanding the transmission and control of many diseases, particuarly rapidly evolving RNA
viruses. However garnering similar insights where pathogens are multi-host is more challenging, particularly when the evolution of the pathogen is slower and pathogen sampling
often heavily biased. This is the case for Mycobacterium bovis, the causative agent of
bovine Tuberculosis (bTB) and for which the Eurasian badger plays an as yet poorly
understood role in transmission and spread. Here we have developed a computational
model that incorporates M. bovis genetic data from cattle only with a highly abstracted
model of an unobserved reservoir. Our research shows that a model in which the reservoir
does not contribute to pathogen diversity, but is a source of infection in spatially localised
areas around each farm, better describes the patterns of outbreaks observed in a population-level sample of a single M. bovis genotype in Northern Ireland over a period of 15
years, compared to models in which either the reservoir has no role, disease spread is spatially extensive, or where they generate considerable diversity on their own. While this reservoir model is not explicitly a model of badgers, its characteristics are consistent with
other data that would suggest a reservoir consisting of infected badgers that contribute
substantially to cattle infection, but could not maintain disease on their own.This study was funded by the following research grants: i) Biotechnology and Biological Sciences Research Council (BB/L010569/1) was awarded to RRK and funded the work of DB, DMW, TM, CM, SM, RAS (www.bbsrc.ac.uk) ii) Biotechnology and Biological Sciences Research Council (BB/L010569/2) was awarded to RRK and funded the work of DB iii) A Wellcome Trust Senior Fellowship (081696/Z/06/Z) was awarded to RRK and funded the work of AOH (www.wellcome.ac.uk) iv) Biotechnology and Biological Sciences Research Council (BB/P010598/1) was awarded to RRK and funded his involvement v) Dept of Agriculture environment and Rural Affairs grant DARD0407 was awared to RAS and funded the work of TM, CM, SM (https://www.daera-ni.gov.uk)
A Bayesian analysis of a Test and Vaccinate or Remove study to control bovine tuberculosis in badgers (Meles meles)
Get PDFPublication history: Accepted - 13 January 2021; Published - 28 January 2021.A novel five year Test and Vaccinate or Remove (TVR) wildlife research intervention project in badgers (Meles meles) commenced in 2014 in a 100km2 area of Northern Ireland. It aimed to increase the evidence base around badgers and bovine TB and help create well-informed and evidence-based strategies to address the issue of cattle-to-cattle spread and spread between cattle and badgers. It involved real-time trap-side testing of captured badgers and vaccinating those that tested negative for bTB (BadgerBCG–BCG Danish 1331) and removal of those that tested bTB positive using the Dual-Path Platform VetTB test (DPP) for cervids (Chembio Diagnostic Systems, Medford, NY USA). Four diagnostic tests were utilised within the study interferon gamma release assay (IGRA), culture (clinical samples and post mortem), DPP using both whole blood and DPP using serum. BCG Sofia (SL222) was used in the final two years because of supply issues with BadgerBCG. Objectives for this study were to evaluate the performance of the DPP in field conditions and whether any trend was apparent in infection prevalence over the study period. A Bayesian latent class model of diagnostic test evaluation in the absence of a gold standard was applied to the data. Temporal variation in the sensitivity of DPP and interferon gamma release assay (IGRA) due to the impact of control measures was investigated using logistic regression and individual variability was assessed. Bayesian latent class analysis estimated DPP with serum to have a sensitivity of 0.58 (95% CrI: 0.40–0.76) and specificity of 0.97 (95% CrI: 0.95–0.98). The DPP with whole blood showed a higher sensitivity (0.69 (95% CrI: 0.48–0.88)) but similar specificity (0.98 (95% Crl: 0.96–0.99)). The change from BCG Danish to BCG Sofia significantly impacted on DPP serum test characteristics. In addition, there was weak evidence of increasing sensitivity of IGRA over time and differences in DPP test sensitivity between adults and cubs. An exponential decline model was an appropriate representation of the infection prevalence over the 5 years, with a starting prevalence of 14% (95% CrI: 0.10–0.20), and an annual reduction of 39.1% (95% CrI: 26.5–50.9). The resulting estimate of infection prevalence in year 5 of the study was 1.9% (95% CrI: 0.8–3.8). These results provide field evidence of a statistically significant reduction in badger TB prevalence supporting a TVR approach to badger intervention. They give confidence in the reliability and reproducibility in the DPP Whole Blood as a real time trap-side diagnostic test for badgers, and describe the effect of vaccination and reduced infection prevalence on test characteristics.The study was funded by the Department
of Agriculture, Environment and Rural Affairs in
Northern Ireland (DAERA)
Detection and characterization of chicken astrovirus associated with hatchery disease in commercial day‑old turkeys in southwestern Nigeria
Get PDFPublication history: Accepted - 25 January 2021; Published - 23 March 2021.Infectious diseases are a major obstacle to profitable poultry production in Nigeria due to the mortality and severe economic
losses they cause. In particular, they are a potent threat to attainment of the food security goals of government and national
self-sufficiency in food production. Thus, there is a need for continuous monitoring of the nation’s poultry population for
these diseases. As part of an ongoing investigation of enteric viruses associated with poor performance or hatchery diseases
in commercial poultry in southwestern Nigeria, intestinal contents from 97 condemned or runted day-old commercial turkey
poults were examined for turkey astroviruses, infectious bronchitis virus, chicken astrovirus (CAstV), avian nephritis virus,
avian rotavirus, avian reovirus, fowl adenovirus, and chicken parvovirus by virus isolation, electron microscopy (EM), polymerase
chain reaction (PCR), and reverse transcription PCR. The samples were collected from five commercial hatcheries
and five farms located in southwestern Nigeria. While all samples tested negative for other viruses, CAstV was detected in
the majority (83.5%) of the birds, although some pleomorphic virus-like particles with surface projections that appeared
fringed or fimbriated were observed in five of the cell culture samples by EM. Phylogenetic analysis revealed these CAstV
strains belonged to the Bi clade. These findings not only implicate CAstV as the major cause of hatchery condemnations in
commercial turkeys in southwestern Nigeria but also highlight the need for experimental studies to further establish its role
in this disease condition