Novel diagnostic tools for improved control, monitoring and prevention strategies for the key endemic diseases of livestock in Scotland
Project Lead
Challenges
Improving the detection and diagnosis of infectious, endemic diseases is a key step to reducing the impacts on animal health and welfare. This enables the implementation of appropriate control measures and integrated management strategies. In addition, the targeted use of existing veterinary products via informed diagnostic decisions can reduce their unnecessary use, limiting environmental contamination and prolonging their efficacy for the future. This will generate positive impacts on the productivity, efficiency, and economic impact of livestock production. Over the long-term, this will improve the sustainability of the Scottish livestock sector. The wider public will directly benefit through increased food safety and security and improved animal welfare.
The key challenges for this project are:
- Current endemic disease diagnostics lack accuracy and specificity
- Developing diagnostic tools that can detect resistance to drugs used to control disease in livestock as well as new and emerging infections
- Exploiting novel technologies to develop new and improved diagnostic platforms
Questions
- What novel diagnostic tools could be developed to improve control, monitoring and prevention strategies for important endemic diseases of livestock in Scotland?
Solutions
Developing novel diagnostic tools for improved control, effective quarantine and targeted treatment of sheep scab
Sheep scab represents a major animal welfare concern and a significant economic burden for the sector in Scotland. The sheep scab ELISA (a serological test) is a significant new tool for improved disease control. However, the antigen used in the test is also part of a prototype scab vaccine. This limits our ability to differentiate vaccinated and infested animals. We are working on a second-generation test and exploring its potential in a pen-side format.
Identifying pathogens associated with bovine respiratory disease (BRD) complex
BRD complex is an important cause of death, disease, and antibiotic usage in calves. We require accurate and specific diagnostics. Clinical signs cannot distinguish the cause. We are identifying the major and novel BRD pathogens to directly develop improved diagnostics with greater pathogen coverage.
Developing a novel diagnostic tool for improved control of Johne’s disease (JD)
Mycobacterium avium subspecies paratuberculosis (MAP) caused JD which is a worldwide production and welfare issue. Although diagnostic tests are available, they lack specificity and/or sensitivity. These issues lead to misdiagnosis, underreporting, reduced user confidence. We are developing a serum ELISA that will help improve the identification of MAP.
Developing a new pen-side, point-of-care (PoC) diagnostics for management of ovine abortions
Diagnostic and surveillance schemes rely on tests performed at specialised labs with long turnaround times. PoC assays provide practical on-farm solutions for rapid assessment of disease outbreaks for livestock management. We are focusing on single or multiplexed PoC tests to reduce costs and delivers a comprehensive approach to field diagnosis.
Improving detection of endemic veterinary pathogens
We require improved diagnostic tests for many veterinary pathogens. These must be sensitive and specific and able to differentiate infected from vaccinated animals. New diagnostics have been developed for many veterinary pathogens. We are evaluating the suitability of one of these new platforms, SHERLOCK, for three priority endemic diseases: i) ovine pulmonary adenocarcinoma, ii) Louping-ill virus, and iii) MAP.
Improving diagnostic rate in livestock abortions
Livestock abortions are a significant health and welfare issue leading to economic losses. Several infectious causes of abortion also present a zoonotic risk. Currently, in a significant proportion of abortion cases submitted for diagnosis an infectious agent cannot be identified. We are investigating the potential use of a deep learning computational image analysis algorithm to identify infectious-agent specific changes in samples of placenta. This will improve the likelihood of reaching a diagnosis of an infectious cause of abortion when other testing is unrewarding.
Improving sequence and serological typing of bovine viral diarrhoea virus (BVDV) infection
Next generation sequencing has potential for diagnostic application, particularly in support of surveillance and disease eradication for BVD. We are designing novel strategies for BVDV genome analysis, supporting infection tracing when BVDV eradication is almost complete.
Detecting macrocyclic lactone insensitivity in the cattle lungworm
Cattle lungworm infections cause significant health and welfare issues and losses in productivity. It can be controlled through pasture management, vaccination and anthelmintics. However, over-use of anthelmintics is linked to anthelmintic resistance (AMR). Little is known about AMR in lungworm in UK cattle but there are anecdotal accounts of lungworm infections persisting following treatment. We are developing less invasive, cheaper, and more rapid diagnostic tests.
Project Partners
Progress
Developing novel diagnostic tools for sheep scab
We aim to develop a blood test using a novel antigen (Pso-EIP-1) providing DIVA capacity (differentiating between infected and vaccinated animals) for integration with a sheep scab vaccine. A serum panel collated from naïve and infested animals, including clinical field cases have been assessed with test performance showing high levels of sensitivity/specificity with excellent discrimination between positive and negative cases.
Identifying pathogens associated with the BRD complex
A natural exposure study was planned, reproducing the most common causes of BRD complex by bringing together unvaccinated calves from multiple sources. A project license application was submitted to the Home Office, but we experienced significant delays in processing the application leading to a delay in the trial, which will now take place in Year 2. Efforts to build an archive of BRD complex lung samples from surveillance submissions have continued, with more than 60 bovine lung samples having been collected.
Developing a novel diagnostic tool for Johne's disease
Moredun holds a serum panel from Johne's affected animals collected from heavily infected and disease-free farms. These will be used to test the diagnostic potential of synthetic mycolic acids. Samples were collated, and the mycolic acid assay is optimized for sample screening.
Developing a pen-side, PoC diagnostic for management of ovine abortions
Collection of ovine abortion tissues with associated metadata is complete and the sample database has been finalised.
Improving the detection of endemic veterinary pathogens
Development of a CRISPR-based molecular diagnostic test for endemic pathogens are underway, with Year 1 focussing on the development of reagents required for test validation, including generation of pathogen-specific guide sequences which will be used for future test development.
Improving diagnostic rate in livestock abortions
The Project aims to improve the accuracy of histopathological diagnosis of livestock abortions by applying digitisation and deep learning methods. Different strategies were evaluated for updating existing surveillance databases, and to identify suitable cases for inclusion into this Work Package. Discussions have been held with Moredun IT to improve the surveillance database.
Improving sequence and serological typing of BVDV infections
This Work Package focusses on the analysis of complete Scottish BVDV genome sequences, including designing new methods for whole genome sequencing of multiple pathogens. The approach was benchmarked on major UK BVDV types (including BVD1a strains) with six BVDV strains having been completed.
Detecting macrocyclic lactone (ML) insensitivity in the cattle lungworm
Developing a test to characterise ML sensitivity in Dictyocaulus larvae. Efforts have focused on optimising sample transportation and development conditions and communication with industry to obtain material from suspected inefficacy cases.
Impacts resulting from the outputs generated in this Project
Policy: The sheep scab blood test is now available as a diagnostic test within the National Testing Programme. This provides resources for diagnostic testing performed by individuals and groups of farmers, working collectively to deal with disease in a sustainable manner. These approaches are being benchmarked in control programmes across the UK, including a project on Lewis and Harris, funded by Scottish Government.
Industry: Direct knowledge exchange impacts delivered to industry through events such as the Royal Highland Show and direct industry meetings (e.g., Elanco, Zoetis and Bimeda). Discussions with diagnostic providers are ongoing to increase availability of the sheep scab test, including changing to a new diagnostic antigen developed in Work Package 1. The test is available through Biobest Labs and Wales Veterinary Science Centre, with SAC and APHA offering the test in 2023. Talks with industry is ongoing to develop a pen-side scab test, which is due in Year 4. Engagement activities in Work Package 8 have leveraged funds from the Veterinary Medicines Directorate (VMD) to fund industry stakeholder workshop on cattle lungworm in March 2023.
Public and Professional: As part of Work Package 8 academia, veterinarians and pharmaceutical stakeholders will come together to develop future recommendations for assessing and treating cattle with suspect ML insensitivity in lungworm and identifying research knowledge gaps. Information from the workshop will be fed back to the Control of Worms Sustainably (COWS) group, which promotes sustainable control of cattle parasites. Research from the project has also been presented at national and international conferences.
Related Projects
To develop novel tools and approaches to improve diagnosis of the most economically important endemic diseases of livestock in Scotland, the UK and Europe. The research will lead to the development of new and more versatile technologies for the accurate diagnosis of infectious disease and investigation of complex disease syndromes (such as reproductive and respiratory diseases...
- Animal Disease
- Water
- 2016-2022