Novel diagnostic tools for improved control, monitoring and prevention strategies for the key endemic diseases of livestock in Scotland

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

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.