scholarly journals When to kill a cull: factors affecting the success of culling wildlife for disease control

2019 ◽  
Vol 16 (152) ◽  
pp. 20180901 ◽  
Author(s):  
Jamie C. Prentice ◽  
Naomi J. Fox ◽  
Michael R. Hutchings ◽  
Piran C. L. White ◽  
Ross S. Davidson ◽  
...  
Keyword(s):  
Disease Control ◽  
Control Strategies ◽  
Wildlife Disease ◽  
Policy Implications ◽  
Disease Spread ◽  
Factors Affecting ◽  
Badger Culling ◽  
Population Reduction ◽  
Control Disease ◽  
The Uk

Culling wildlife to control disease can lead to both decreases and increases in disease levels, with apparently conflicting responses observed, even for the same wildlife–disease system. There is therefore a pressing need to understand how culling design and implementation influence culling's potential to achieve disease control. We address this gap in understanding using a spatial metapopulation model representing wildlife living in distinct groups with density-dependent dispersal and framed on the badger–bovine tuberculosis (bTB) system. We show that if population reduction is too low, or too few groups are targeted, a ‘perturbation effect’ is observed, whereby culling leads to increased movement and disease spread. We also demonstrate the importance of culling across appropriate time scales, with otherwise successful control strategies leading to increased disease if they are not implemented for long enough. These results potentially explain a number of observations of the dynamics of both successful and unsuccessful attempts to control TB in badgers including the Randomized Badger Culling Trial in the UK, and we highlight their policy implications. Additionally, for parametrizations reflecting a broad range of wildlife–disease systems, we characterize ‘Goldilocks zones’, where, for a restricted combination of culling intensity, coverage and duration, the disease can be reduced without driving hosts to extinction.

Further studies on epidemiological factors influencing control of banana bunchy top disease and evaluation of control measures by computer simulation

1987 ◽  
Vol 38 (2) ◽  
pp. 373
Author(s):  
RN Allen
Keyword(s):  
Disease Control ◽  
Control Measure ◽  
Significant Loss ◽  
Control Measures ◽  
Disease Spread ◽  
Disease Symptoms ◽  
Control Disease ◽  
Banana Leaves ◽  
Time Required ◽  
Apparently Healthy

The basic infection rate of bunchy top disease in established bananas averaged 0.0342 new infections per infectious plant per day, but varied seasonally with a maximum in summer. The mean distance of spread for the aphid vector was 15.2 m. The latent period was 59.8 days and correlated with the time required for the growth of 3.7 new banana leaves. A microcomputer program was written to simulate spread of banana bunchy top disease in space and time. In the absence of disease control, disease spread from an initial primary infection in July or January to 124 or 153 infected plants, respectively, in one year. When disease control was maintained by removing diseased plants whenever the number of infected plants exceeded a given threshold, the numbers of diseased plants detected each inspection were positively correlated with the infection threshold, but the numbers of inspections required to maintain control increased markedly as the infection threshold was decreased. A practice of removing apparently healthy plants within 5 m of plants detected with bunchy top disease symptoms in five or more leaves was found to locate about 30% of the remaining undetected infected plants when disease was first detected in a plantation. However, its use as a routine control measure was ineffective in reducing the number of inspections required to maintain control or in reducing the risk of disease spreading to adjoining plantations. Removal of apparently healthy plants within 5 m had some bearing on disease control when applied around plants with disease symptoms in two leaves or less, but also caused a significant loss of healthy plants.

The Effect of Farmer Capacities, Farm Business Resources and Perceived Support of Family, Friends and Associational Networks on Intentions to Invest in Renewable Energy Ventures in the UK

2013 ◽  
pp. 1072-1088
Author(s):  
Aurelian Mbzibain
Keyword(s):  
Positive Influence ◽  
Postal Survey ◽  
Policy Implications ◽  
Perceived Support ◽  
Factors Affecting ◽  
Farm Diversification ◽  
Land Tenancy ◽  
The Uk ◽  
Farm Business ◽  
Investment Intentions

The specific role of farmers and their actual or potential involvement with RE adoption and the wider community is potentially important but has not been addressed by research. This research carried out a postal survey of 2000 (response rate of 20.1%) farmers in the West Midlands region of the UK to investigate some of the factors affecting farmers’ intentions to invest in RE production and associated enterprises. Multivariate linear regressions showed that the farmer’s level of education, level of farm diversification, land tenancy status and farm business turnovers were the most important factors affecting intentions. It also emerged that perceived support of family, friends and associational networks was a significant positive influence on farmer’s investment intentions. The policy implications for these results are discussed.

scholarly journals Factors affecting the voluntary use of internal audit: evidence from the UK

2018 ◽  
Vol 33 (3) ◽  
pp. 288-317 ◽  
Author(s):  
Hazem Ramadan Ismael ◽  
Clare Roberts
Keyword(s):  
Corporate Governance ◽  
Agency Theory ◽  
Internal Control ◽  
Audit Committee ◽  
Internal Audit ◽  
Theoretical Framework ◽  
Policy Implications ◽  
Content Type ◽  
Factors Affecting ◽  
The Uk

Purpose This study aims to identify the factors that lead non-financial companies listed in the UK to use an internal audit function (IAF) as a monitoring mechanism. Although the use of an IAF in the UK is voluntary, no prior research has examined the drivers for using one. Design/methodology/approach Financial and non-financial data were collected from the annual reports of 332 UK non-financial companies listed on the London Stock Exchange (LSE) Main Market. Univariate tests and multivariate logistic regression tests were used to test the research hypotheses. A theoretical framework based on both agency theory and transaction cost economics (TCE) theory was used to explain the economic factors affecting the use of an IAF. Findings The study provides evidence that firm size, level of internal risks, agency problem between owners and managers and existence of an effective audit committee are associated with the existence of an IAF. Thus, the need to have strong internal control and risk management systems and to reduce both internal and external agency costs drives companies to have an IAF. These results suggest the importance of IAF as an internal corporate governance tool and the effectiveness of UK governance regulations in monitoring the effectiveness of internal control systems. Practical implications Given the importance of the IAF’s corporate governance role, the study provides some policy implications. Regulators should pay more attention to the issue of maintaining an IAF, especially by large companies, the relationship between the IAF and other governance parties, especially the audit committee, and the disclosure of more relevant information about the IAF’s characteristics and practices. Originality/value This is the first study to examine the factors affecting the existence of the IAF within the UK’s distinctive regulatory approach of “comply or disclose reasons”. Furthermore, it provides a theoretical framework that explains how both the agency theory and TCE theory can interpret the adoption of internal audit.

The future of controlling and eradicating TB from infected cattle herds

Livestock ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 137-141
Author(s):  
R J Sibley
Keyword(s):  
Risk Management ◽  
Disease Control ◽  
Bovine Tuberculosis ◽  
Control Strategies ◽  
Economic Problem ◽  
Infected Cattle ◽  
Novel Technologies ◽  
Specific Disease ◽  
Cattle Herds ◽  
The Uk

Bovine tuberculosis is a major economic problem for the cattle farmers of the UK, particularly the endemically infected are as of the south and west. Attempts at eradication have failed to effectively control the disease: of farms that suffer a breakdown and are then deemed clear of disease, more than half will suffer recurrence of the disease within 3 years, while a significant number of farms remain chronically infected. These herds provide a major reservoir of infection and robust, farm specific, disease control strategies are required to manage the disease from them, economically and sustainably. Novel technologies in surveillance, resilience and risk management are required to effectively control bovine tuberculosis in these endemically infected herds.

scholarly journals Disease-economy trade-offs under alternative pandemic control strategies

2021 ◽  
Author(s):  
Thomas Ash ◽  
Antonio M. Bento ◽  
Daniel Kaffine ◽  
Akhil Rao ◽  
Ana I. Bento
Keyword(s):  
Control Strategies ◽  
Coupled Systems ◽  
Disease Spread ◽  
Effective Control ◽  
Economic Losses ◽  
Coordination Failure ◽  
Economic Activities ◽  
Trade Offs ◽  
Data Driven Approach ◽  
Control Disease

AbstractPublic policy and academic debates regarding pandemic control strategies note potential disease-economy trade-offs, and often prioritize one outcome over the other. Using a calibrated, coupled epi-economic model of individual behavior embedded within the broader economy during a novel epidemic, we show that targeted isolation strategies can avert up to 91% of individual economic losses relative to voluntary isolation strategies. Notably, the economic savings from targeted isolation strategies do not impose an additional disease burden, avoiding disease-economy trade-offs. In contrast, widely-used blanket lock-downs do create sharp disease-economy trade-offs and impose substantial economic costs per additional case avoided. These results highlight the benefits of targeted isolation strategies for disease control, as targeted isolation addresses the fundamental coordination failure between infectious and susceptible individuals that drives the recession. Our coupled-systems framework uses a data-driven approach to map economic activities to contacts, which facilitates developing effective control strategies for future novel pathogens. Implementation of this framework can help control disease spread and potentially avert trillions of dollars in losses.

The Effect of Farmer Capacities, Farm Business Resources and Perceived Support of Family, Friends and Associational Networks on Intentions to Invest in Renewable Energy Ventures in the UK

2013 ◽  
Vol 2 (3) ◽  
pp. 43-58
Author(s):  
Aurelian Mbzibain
Keyword(s):  
Positive Influence ◽  
Postal Survey ◽  
Policy Implications ◽  
Perceived Support ◽  
Factors Affecting ◽  
Farm Diversification ◽  
Land Tenancy ◽  
The Uk ◽  
Farm Business ◽  
Investment Intentions

The specific role of farmers and their actual or potential involvement with RE adoption and the wider community is potentially important but has not been addressed by research. This research carried out a postal survey of 2000 (response rate of 20.1%) farmers in the West Midlands region of the UK to investigate some of the factors affecting farmers’ intentions to invest in RE production and associated enterprises. Multivariate linear regressions showed that the farmer’s level of education, level of farm diversification, land tenancy status and farm business turnovers were the most important factors affecting intentions. It also emerged that perceived support of family, friends and associational networks was a significant positive influence on farmer’s investment intentions. The policy implications for these results are discussed.

Patterns of direct and indirect contact between cattle and badgers naturally infected with tuberculosis

2013 ◽  
Vol 141 (7) ◽  
pp. 1467-1475 ◽  
Author(s):  
J. A. DREWE ◽  
H. M. O'CONNOR ◽  
N. WEBER ◽  
R. A. McDONALD ◽  
R. J. DELAHAY
Keyword(s):  
Disease Transmission ◽  
Meles Meles ◽  
Indirect Interactions ◽  
Disease Spread ◽  
Indirect Contact ◽  
Contact Patterns ◽  
Contact Behaviour ◽  
Control Disease ◽  
The Uk ◽  
South West England

SUMMARYTuberculosis (TB) due to infection with Mycobacterium bovis is transmitted between cattle and badgers (Meles meles) in the UK and Ireland but it is unclear where or when transmission occurs. We investigated direct and indirect interactions between badgers and cattle using automated proximity loggers on animals and at badger latrines located on pasture, in an area of south-west England with a high-density badger population. Direct contacts (interactions within 1·4 m) between badgers and cattle at pasture were very rare (four out of >500 000 recorded animal-to-animal contacts) despite ample opportunity for interactions to occur. Indirect interactions (visits to badger latrines by badgers and cattle) were two orders of magnitude more frequent than direct contacts: 400 visits by badgers and 1700 visits by cattle were recorded. This suggests that indirect contacts might be more important than direct contacts in terms of disease transmission at pasture. The TB infection status of individual badgers (ascribed with 93% accuracy using three diagnostic tests) did not affect the frequency or duration of their visits to latrines located on pasture grazed by cattle. Nevertheless, there was wide variation in contact behaviour between individuals, which highlights the importance of understanding heterogeneity in contact patterns when developing strategies to control disease spread in wildlife and livestock.

Corrigendum - Further studies on epidemiological factors influencing control of banana bunchy top disease and evaluation of control measures by computer simulation

1987 ◽  
Vol 38 (2) ◽  
pp. 373
Author(s):  
RN Allen
Keyword(s):  
Disease Control ◽  
Control Measure ◽  
Significant Loss ◽  
Control Measures ◽  
Disease Spread ◽  
Disease Symptoms ◽  
Control Disease ◽  
Banana Leaves ◽  
Time Required ◽  
Apparently Healthy

The basic infection rate of bunchy top disease in established bananas averaged 0.0342 new infections per infectious plant per day, but varied seasonally with a maximum in summer. The mean distance of spread for the aphid vector was 15.2 m. The latent period was 59.8 days and correlated with the time required for the growth of 3.7 new banana leaves. A microcomputer program was written to simulate spread of banana bunchy top disease in space and time. In the absence of disease control, disease spread from an initial primary infection in July or January to 124 or 153 infected plants, respectively, in one year. When disease control was maintained by removing diseased plants whenever the number of infected plants exceeded a given threshold, the numbers of diseased plants detected each inspection were positively correlated with the infection threshold, but the numbers of inspections required to maintain control increased markedly as the infection threshold was decreased. A practice of removing apparently healthy plants within 5 m of plants detected with bunchy top disease symptoms in five or more leaves was found to locate about 30% of the remaining undetected infected plants when disease was first detected in a plantation. However, its use as a routine control measure was ineffective in reducing the number of inspections required to maintain control or in reducing the risk of disease spreading to adjoining plantations. Removal of apparently healthy plants within 5 m had some bearing on disease control when applied around plants with disease symptoms in two leaves or less, but also caused a significant loss of healthy plants.

scholarly journals Quantifying the dynamics of pig movements improves targeted disease surveillance and control plans

2019 ◽  
Author(s):  
Gustavo Machado ◽  
Jason Ardila Galvis ◽  
Francisco Paulo Nunes Lopes ◽  
Joana Voges ◽  
Antônio Augusto Rosa Medeiros ◽  
...  
Keyword(s):  
Disease Control ◽  
Disease Surveillance ◽  
Control Strategies ◽  
Disease Spread ◽  
Growth Stages ◽  
Case Scenario ◽  
Modeling Framework ◽  
Worst Case ◽  
Movement Data ◽  
The Impact

SummaryTracking animal movements over time can fundamentally determine the success of disease control interventions throughout targeting farms that are tightly connected. In commercial pig production, animals are transported between farms based on growth stages, thus it generates time-varying contact networks that will influence the dynamics of disease spread. Still, risk-based surveillance strategies are mostly based on a static network. In this study, we reconstructed the static and temporal pig networks of one Brazilian state from 2017 to 2018, comprising 351,519 movements and 48 million transported pigs. The static networks failed to capture time-respecting movement pathways. Therefore, we propose a time-dependent network susceptible-infected (SI) model to simulate the temporal spread of an epidemic over the pig network globally through the temporal movement of animals among farms, and locally with a stochastic compartmental model in each farm, configured to calculate the minimum number of target farms needed to achieve effective disease control. In addition, we propagated disease on the pig temporal network to calculate the cumulative contacts as a proxy of epidemic sizes and evaluated the impact of network-based disease control strategies. The results show that targeting the first 1,000 farms ranked by degree would be sufficient and feasible to diminish disease spread considerably. Our finding also suggested that assuming a worst-case scenario in which every movement transmit disease, pursuing farms by degree would limit the transmission to up to 29 farms over the two years period, which is lower than the number of infected farms for random surveillance, with epidemic sizes of 2,593 farms. The top 1,000 farms could benefit from enhanced biosecurity plans and improved surveillance, which constitute important next steps in strategizing targeted disease control interventions. Overall, the proposed modeling framework provides a parsimonious solution for targeted disease surveillance when temporal movement data is available.

An ex-ante economic appraisal of Bluetongue virus incursions and control strategies

2015 ◽  
Vol 154 (1) ◽  
pp. 118-135 ◽  
Author(s):  
A. FOFANA ◽  
L. TOMA ◽  
D. MORAN ◽  
G. J. GUNN ◽  
S. GUBBINS ◽  
...  
Keyword(s):  
Bluetongue Virus ◽  
Control Strategies ◽  
Unit Cost ◽  
Disease Outbreaks ◽  
Cost Benefit ◽  
Vaccination Strategy ◽  
Disease Spread ◽  
Public And Private ◽  
Ex Ante ◽  
The Uk

SUMMARYThe incursion of Bluetongue disease into the UK and elsewhere in Northern Europe in 2008 raised concerns about maintaining an appropriate level of preparedness for the encroachment of exotic diseases as circumstances and risks change. Consequently the Scottish government commissioned the present study to inform policy on the specific threat of Bluetongue virus 8 (BTV8) incursion into Scotland. An interdisciplinary expert panel, including BTV and midge experts, agreed a range of feasible BTV incursion scenarios, patterns of disease spread and specific control strategies. The study was primarily desk-based, applying quantitative methodologies with existing models, where possible, and utilizing data already held by different members of the project team. The most likely distribution of the disease was explored given Scotland's agricultural systems, unique landscape and climate. Epidemiological and economic models are integrated in an ex-ante cost-benefit appraisal of successful prevention of hypothetical BTV8 incursion into Scotland under various feasible incursion scenarios identified by the interdisciplinary panel. The costs of current public and private surveillance efforts are compared to the benefits of the avoided losses of potential disease outbreaks. These avoided losses included the direct costs of alternative vaccination, protection zone (PZ) strategies and their influence on other costs arising from an outbreak as predicted by the epidemiological model. Benefit-cost ratios were ranked within each incursion scenario to evaluate alternative strategies. In all incursion scenarios, the ranking indicated that a strategy, including 100% vaccination within a PZ set at Scottish counties along the England–Scotland border yielded the least benefit in terms of the extent of avoided outbreak losses (per unit cost). The economically optimal vaccination strategy was the scenario that employed 50% vaccination and all Scotland as a PZ. The results provide an indicator of how resources can best be targeted for an efficient ex-ante control strategy.

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