DAERA funded Evidence & Innovation Projects

Area of Expertise:

AFBI Veterinary Sciences Division undertakes a number of Evidence &Innovation Projects for DAERA

The role of endemic diseases and other factors in the occurrence of bovine tuberculosis

Recent research has indicated that the occurrence of concurrent infections (hosts with more than one viral/bacterial/parasitic infection during a given period) can affect the infectious status of cattle herds with regards bovine tuberculosis (bTB).

Concurrent infections may affect the immune system of their host in a way that could cause the misdiagnosis or exacerbation of infection. In human medicine, a wide range of co-factors have been implicated in changing the patterns and development of human tuberculosis.  These include viral infections (e.g. HIV), parasitism (e.g. fluke), exposure to environmental mycobacteria and macro- and micro-nutrient balances. 

The project seeks to assess whether there are significant effects of three major endemic diseases of cattle (liver fluke, Johne’s Disease and Bovine Viral Diarrhoea (BVD)) on the disclosure of bTB in cattle in Northern Ireland. Epidemiological studies will compare animals and herds with and without evidence of co-infection to assess if there are differences in terms of the probability of herds “breaking down” with bTB and the size of those breakdowns.

Knowledge of the relative role of concurrent infections in the epidemiology of bTB will be an important step forward for the bTB eradication scheme. With such knowledge, new strategies aimed at identifying more infected animals could be developed, while also opening up the possibility of integrated management of interrelated endemic diseases.

Investigations into antimicrobial resistance and veterinary antimicrobial prescribing practice in Northern Ireland

Antimicrobial resistance is a term used for microorganisms with the ability to withstand antimicrobial treatments. The emergence and spread of microorganisms with antimicrobial resistance can render treatments ineffective and pose a serious risk to public and animal health. A well known example of a bacterium that has acquired resistance to multiple antibiotics is Meticillin-resistant Staphylococcus aureus (MRSA).

There has been concern about the possibility of the transfer of resistant bacteria and/or resistance genes from animals to humans through food. This study is assessing the levels of antimicrobial resistance in commensal (normal) E. coli carried by dairy cattle in Northern Ireland and the antimicrobial resistance genes present.

The project is developing advanced molecular DNA platforms within the Veterinary Sciences Department (VSD) of AFBI to enable the detection and characterisation of antimicrobial resistance genes. This technology can be used to monitor changes in antimicrobial resistance patterns in bacterial populations.

The work also includes a review of currently published guidance on responsible use of antimicrobials in animals. The collective outcomes of this study will be used to inform DAERA policy in this area.

An assessment of commercially available serological tests for the detection of cattle infected with bovine tuberculosis

Recently, commercially available antibody tests have been released onto the market, claiming advances in antibody detection and capacity to improve diagnosis of bovine TB.  Front line tests in current use include the skin test and interferon gamma test, but these fail to identify all cattle infected with M. bovis, the organism responsible for bovine TB.

There are some indications that serology tests may be most effectively applied when animals are in the late stages of disease and when they are most infectious. This study will determine the usefulness of antibody detection in the NI disease control programme through evaluation of new antibody tests and their potential advantages such as the greater time between sampling and testing, potential for high throughput as well as cost savings.

This study will validate antibody tests using animals with confirmed disease status in order to define relative specificity and sensitivity as well as measure the impact of the skin test on subsequent tests. The effectiveness of these tests will be measured against the skin test and the interferon gamma assay.

An assessment of farmers’ understanding of biosecurity measures, the consequences of not applying biosecurity measures and their attitudes towards applying biosecurity measures when dealing with diseases

This project is seeking to address the knowledge gap surrounding what farmers (specifically cattle and sheep farmers) think about disease control and biosecurity measures. A literature review was conducted that described what practices are being undertaken internationally with respect to biosecurity and the economic impact of the failure to control disease.

A survey was has been conducted that sought the views of cattle and sheep farmers in Northern Ireland on animal disease management and control including biosecurity measures. Responses have been analysed and a stakeholder event has enabled engagement with interested parties in order to interpret and inform the analysis of results.

The project will help to inform DAERA policy decision on biosecurity measures locally.

An evaluation of the role of multiple reactor and chronic breakdown herds in the epidemiology of bovine tuberculosis in Northern Ireland

Bovine tuberculosis is widely regarded as one of the most complex animal diseases that the government, the agricultural industry and the veterinary profession in Northern Ireland is facing. In addition to the consequences for animal and human health, bovine TB also has significant financial implications with an estimated 25 million pounds per year government spend on bovine TB control in Northern Ireland alone.

Data exploration conducted for other studies by AFBI and DAERA suggest very significant clustering of bovine TB infection in a small percentage of herds in Northern Ireland. The aim of this project is to undertake an evaluation of the incidence and significance of cattle herds in Northern Ireland that have multiple reactors and/or have suffered from prolonged breakdowns.

The aim of the project is also to utilise an important resource unique to Northern Ireland, high resolution (VNTR) strain typing data, to help understand how chronic herds cluster in space and time. The exposure to possible risk factors, including wildlife, will be evaluated in this study.

The overall outcome of this project will be to provide information on understanding the spatio-temporal epidemiology of chronic herds, and improving the strategy as in how to deal with these multiple reactor and or chronic breakdown herds in the future.

Investigating TB transmission dynamics using genome epidemiology

In order to improve bovine TB control, it remains fundamental to describe and explain the basic biological processes of TB maintenance and transmission (source and spread).

AFBI has developed high-resolution DNA “fingerprinting” (strain typing) methods which allow the identification and tracking of genetically distinct M. bovis strains, allowing epidemiologically-linked cases and herds to be more accurately identified.  

These genetic tests differentiate TB bacteria at different geographic and evolutionary scales. These analyses show that TB bacteria are specific to particular regions.

At a local scale these tests facilitate studies on disease maintenance and spread by tracking the transmission of particular TB bacteria molecular types or strains. 

In this project, AFBI, working in collaboration with disease ecology experts at the University of Glasgow, will use a combination of molecular typing, bacterial whole-genome sequencing and mathematical modelling to investigate TB transmission dynamics in TB-affected cattle and badgers within a defined study area. Such analyses should inform our understanding of how TB maintains and spreads in the landscape.

An evaluation of interferon-gamma (IFN-g) testing for bovine TB in Northern Ireland

The aim of this project is to evaluate the blood based interferon-gamma (IFN-g) test for bovine tuberculosis as it is currently used in NI.

The study includes an evaluation of factors that influence test result such as animal age, sex, and breed as well as herd factors such as bovine TB test history and size.  To achieve this, laboratory and animals data have been extracted from APHIS and laboratory records and are being analysed to describe the relative numbers of animals testing positive categorised by sex, age and production type using more than one test cut-off. 

These results have been compared to the skin test results using both standard and severe interpretations.  Test results have also been compared to post mortem findings to assess the relative performance of each test and combination of tests. 

The project consists of a series of different epidemiological outputs. These include a multivariable analysis of risk factors affecting the likelihood of post-mortem positive result to bovine tuberculosis under field conditions in Northern Ireland; estimates of sensitivity and specificity of SICTT, gamma interferon test and meat inspection using Bayesian latent class modelling and a survival analysis of skin test negative/gamma interferon positive and negative animals that remain on-farm.