Andrew W. Byrne

Department of Agriculture Food and the Marine · One Health Scientific Support Unit

Bovine tuberculosis (bTB) remains a prominent zoonotic pathogen on the world stage, with significant impacts on animal and human health, and economic well-being. Eradication is hampered by a complex epidemiology, which in many global territories involves wildlife hosts. Indeed, it is humbling to realize that despite advances in understanding gleane...

Objectives: Our objective was to review the literature on the inferred duration of the infectious period of COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus, and provide an overview of the variation depending on the methodological approach. Design: Rapid scoping review. Literature review with fixed search te...

Objectives The aim of this study was to conduct a rapid systematic review and meta-analysis of estimates of the incubation period of COVID-19. Design Rapid systematic review and meta-analysis of observational research. Setting International studies on incubation period of COVID-19. Participants Searches were carried out in PubMed, Google Scholar...

Bovine tuberculosis (bTB) continues to be a problem in cattle herds in Ireland and Britain. It has been suggested that failure to eradicate this disease is related to the presence of a wildlife reservoir (the badger). A large-scale project was undertaken in the Republic of Ireland during 1997–2002 to assess whether badger removal could contribute t...

Bovine tuberculosis (bTB), caused by Mycobacterium bovis, is a serious infectious disease that remains an ongoing concern for cattle farming worldwide. Tuberculin skin-tests are often used to identify infected animals (reactors) during test-and-cull programs, however, due to relatively poor sensitivity, additional tests can be implemented in parall...

Published findings from an AFBI, DSIB DAERA funded research project, examining Northern Irelands livestock pestiviruses.

The importance of gaining a greater understanding of the infectious diseases of wild animal populations and the impact of emerging and re-emerging pathogens has never been more sharply in focus than in the current post-COVID-19 world. The zoonotic origin of the pandemic [1], its links with damaging human impacts on nature [2] and increasing public...

Zoonotic diseases represent a significant societal challenge in terms of their health and economic impacts. One Health approaches to managing zoonotic diseases are becoming more prevalent, but require novel thinking, tools and cross-disciplinary collaboration. Bovine tuberculosis (bTB) is one example of a costly One Health challenge with a complex...

Bovine viral diarrhoea (BVD) is caused by Pestivirus A and Pestivirus B. Northern Ireland (NI) embarked on a compulsory BVD eradication scheme in 2016, which continues to this day, so an understanding of the composition of the pestivirus genotypes in the cattle population of NI is required. This molecular epidemiology study employed 5ʹ untranslate...

Free‐living amoebae (FLA) serve as hosts for a variety of endosymbionts, which are microorganisms that reside and multiply within the FLA. Some of these endosymbionts pose a pathogenic threat to humans, animals, or both. The symbiotic relationship with FLA not only offers these microorganisms protection but also enhances their survival outside thei...

Abstract Antimicrobial resistance (AMR) in animal and human pathogens is a global One-Health threat. The association between antimicrobial use (AMU) and the evolution of dissemination of AMR bacteria and their associated resistance genes highlights the importance of monitoring and control of AMU. Here we present an analysis of national monitoring d...

The European badger, Meles meles, is an important wildlife host for Mycobacterium bovis and contributes to the epidemiology of bovine tuberculosis (bTB) in cattle in several countries. The control of zoonotic diseases, such as bTB, is a central component of global One-Health strategies. Such strategies are complicated by human-wildlife conflicts, p...

Aims Antimicrobial resistance (AMR) is of significant global concern and is a major One Health issue. There is evidence to suggest that increased antimicrobial usage (AMU) can be associated with AMR patterns, and therefore, there have been efforts to reduce AMU in anticipation of reducing AMR emergence risk. The aim of this study was to investigate...

Surveillance of endemic pathogens is essential for disease control, providing an evidence base for policy and advice. Bovine Herpes Virus Type 1 (BoHV-1), the causative agent of Infectious Bovine Rhinotracheitis (IBR), has been found to have high seroprevalence within the Irish cattle population. The aim of the present study was to establish seropr...

A new Irish bovine tuberculosis (bTB) eradication strategy was launched in 2021. The strategy was formulated following extensive discussions with stakeholders, formal reviews of several aspects of the existing bTB policy and relevant inputs from the latest scientific research projects. A stakeholder discussion body, the TB Forum, had been establish...

Bovine tuberculosis (bTB), caused by Mycobacterium bovis, is one of the most challenging and persistent health issues in many countries worldwide. In several countries, bTB control is complicated due to the presence of wildlife reservoirs of infection, i.e. European badger (Meles meles) in Ireland and the UK, which can transmit infection to cattle....

European badgers are a wildlife reservoir of infection for Mycobacterium bovis on the island of Ireland. Understanding how exposure risk and badger population management is related to bovine tuberculosis epidemiology in cattle herds has led to a rich body of research. Here we review progress that has been made in the understanding of the eco-epidem...

Surveillance of endemic pathogens is essential for disease control, providing an evidence base for policy and advice. Bovine Herpes Virus Type 1 (BoHV-1), the causative agent of Infectious Bovine Rhinotracheitis (IBR), has been found to have high seroprevalence within the Irish cattle population. The aim of the present study was to establish seropr...

Dairy systems require that each cow calves annually to have an efficient milk production cycle. In systems where milk production is maximized, the male offspring from dairy breed sires tend to have poor beef production traits and, therefore, can be of low economic value. Few studies have been published on the factors impacting early slaughtering of...

Background: Zoonotic diseases represent a significant societal challenge in terms of their health and economic impacts. One Health approaches to managing zoonotic diseases are becoming more prevalent, but require novel thinking, tools and cross-disciplinary collaboration. Bovine tuberculosis (bTB) is one example of a costly One Health challenge wit...

Bovine tuberculosis (bTB) is a disease of significant economic and zoonotic importance, therefore, optimising tests for the identification of Mycobacterium bovis infected cattle is essential. The Interferon Gamma (IFN-γ) Release Assay (IGRA) can diagnose M. bovis infected cattle at an early stage, is easy to perform and can be used alongside skin t...

Bovine tuberculosis (bTB) is a costly, epidemiologically complex, multi-host, endemic disease. Lack of understanding of transmission dynamics may undermine eradication efforts. Pathogen whole-genome sequencing improves epidemiological inferences, providing a means to determine the relative importance of inter- and intra-species host transmission fo...

Slaughterhouse or meat factory surveillance to detect factory lesions (FL) at slaughter is an important part of the bovine tuberculosis (bTB) eradication program in Ireland. The objective of this study was to quantify the effectiveness of Irish slaughterhouses or factories in submitting FL and the proportion of those submitted FL confirmed as being...

Understanding the mechanisms underpinning animal movement patterns is one of the key goals of animal ecology. The motivation to move across populations can be driven by a number of factors, including finding new mates, reducing competition or exploiting new resources. The movement ecology of wildlife hosts of zoonotic diseases—e.g. European badgers...

Bovine tuberculosis (bTB), caused by Mycobacterium bovis, remains a high-priority global pathogen of concern. The role of youngstock animals in the epidemiology of bTB has not been a focus of contemporary research. Here we have aimed to collate and summarize what is known about the susceptibility, diagnosis, transmission (infectiousness), and epide...

Continual tailoring of control programmes of endemic pathogens during long-term eradication campaigns requires detailed analysis of surveillance data to inform evidence-based policy. Bovine tuberculosis is a disease where long-term control and eradication programs are in train in several countries. The primary diagnostic tool, the intradermal tuber...

Background Johne’s disease is a chronic granulomatous enteritis of cattle and other ruminants of economic, animal and public health significance, caused by Mycobacterium avium subsp. paratuberculosis. It is endemic in UK, but there is currently limited information in Northern Ireland. To address this gap, for the first time surveillance data were u...

Culling the main wildlife host of bovine tuberculosis in Great Britain (GB) and Ireland, the European badger (Meles meles), has been employed in both territories to reduce infections in cattle. In GB, this has been controversial, with results suggesting that culling induces disturbance to badger social structure, facilitating wider disease dissemin...

Disturbance ecology refers to the study of discrete processes that disrupt the structure or dynamics of an ecosystem. Such processes can, therefore, affect wildlife species ecology, including those that are important pathogen hosts. We report on an observational before-and-after study on the association between forest clearfelling and bovine tuberc...

Understanding the mechanisms underpinning animal movement patterns is one of the key goals of animal ecology. The motivation to move across populations can be driven by a number of factors, including finding new mates, reducing competition or exploiting new resources. The movement ecology of wildlife hosts of zoonotic diseases – e.g. European badge...

Human modification of landscapes and associated disturbances may facilitate the emergence and spread of zoonotic diseases. Policy‐makers need better understanding of the link between anthropogenic disturbances and wildlife disease hosts at the interface of human society and the natural environment, for example agriculture, forestry and aquaculture....

Bovine tuberculosis (BTB) remains as a persistent disease in Ireland. Historically since 2005 in Ireland, targeted badger culling has been implemented as part of the BTB control/eradication program and has reduced badger densiities in BTB endemic areas. Lowering badger densities in large areas of agricultural grassland has been shown previously to...

Objective: In the process of eradication of M.bovis in an area, quantification of the reproduction ratio parameter (R) is important to assess the current situation and to guide improvement of the eradication effort. For eradication we strive to have R<1 and thus we want to know during the process how close R is to 1. However, for an infection that...

Background Bovine Viral Diarrhoea Virus (BVDV) infection remains endemic in many countries worldwide. Ireland, in common with several other European counties, commenced an BVDV eradication programme in the last decade, Managing eradication programmes requires careful monitoring of diseases prevalence and understanding factors associated with diseas...

Farmland fragmentation is considered to be a defining feature of Northern Ireland’s (NI) agricultural landscape, influencing agricultural efficiency, productivity, and the spread of livestock diseases. Despite this, the full extent of farmland fragmentation in cattle farms in NI is not well understood, and little is known of how farmland fragmentat...

Bovine tuberculosis remains a challenging endemic pathogen of cattle in many parts of the globe. Spatial clustering of Mycoacterium bovis molecular types in cattle suggests that local factors are the primary drivers of spread. Northern Ireland’s agricultural landscape is comprised of highly fragmented farms, distributed across spatially discontinuo...

Rabbit haemorrhagic disease virus 2 (RHDV2; GI.2) is a pathogenic lagovirus that emerged in 2010, and which now has a global distribution. Outbreaks have been associated with local population declines in several lagomorph species, due to rabbit haemorrhagic disease (RHD)-associated mortality raising concerns for its potential negative impact on thr...

Bovith recene tuberculosis (bTB) continues to be a pathogen of concern in several countries globally. Analysis of areas that have higher incidences of bTB outbreaks has demonstrated how risk is not equally distributed, and local data collection, analysis and participatory engagement is required to develop tailored approaches. The Burren, an interna...

Bovine tuberculosis (bTB) remains a challenging endemic pathogen of cattle in many parts of the globe. Spatial clustering of Mycoacterium bovis molecular types in cattle suggests that local factors are the primary drivers of spread. Northern Ireland's agricultural landscape is comprised of highly fragmented farms, distributed across spatially disco...

Bovine tuberculosis (bTB) is a chronic infectious disease caused by Mycobacterium bovis which results in a significant economic cost to cattle industries and governments where it is endemic. In Ireland, the European badger is the main wildlife reservoir of infection. In this study, we investigated whether (motorway) road construction was associated...

Background Rabbit haemorrhagic disease virus (RHDV) is a Lagovirus , a subgroup of the family Caliciviridae . RHDV2 is a variant first described in France in 2010, and has since spread globally. It has been reported in several Lagomorph species (rabbits, hares, and their relatives) as well as other mammals including voles and shrews. The disease ha...

Farm fragmentation is the occurrence of numerous and often discontinuous land parcels associated with a single farm. Farm fragmentation is considered to be a defining feature of Northern Ireland’s (NI) agricultural landscape, influencing agricultural efficiency, productivity, and the spread of livestock diseases. Despite this, the full extent of fa...

Estimating population size in space and time is essential for applied ecology and wildlife management purposes; however, making accurate and precise estimates at large scales is highly challenging. An example is the European badger ( Meles meles ), a widespread and abundant mammal in Ireland. Due to their role in the epidemiology of bovine tubercul...

Background: There has been very little previous research in Ireland on the opinions of farmers regarding dairy beef integration. The need for increased dairy beef integration has assumed a greater importance in Ireland in recent years due to a rapid expansion in dairy production, and associated increase in numbers of male dairy calves born on Irish...

Objective To estimate the proportion of presymptomatic transmission of SARS-CoV-2 infection that can occur, and the timing of transmission relative to symptom onset. Setting/design Secondary analysis of international published data. Data sources Meta-analysis of COVID-19 incubation period and a rapid review of serial interval and generation time,...

Bovine tuberculosis (bTB) remains a significant endemic pathogen of cattle herds, despite multi-decadal control programmes being in place in several countries. Understanding the risks of future bTB breakdown (BD) and the associated characteristics of herds and index breakdowns could help inform risk categorisation. Such risk categories could then c...

Objectives The aim of this study was to determine the relative infectiousness of asymptomatic SARS-CoV-2 infected persons compared with symptomatic individuals based on a scoping review of available literature. Design Rapid scoping review of peer-reviewed literature from 1 January to 5 December 2020 using the LitCovid database and the Cochrane lib...

Objectives The aim of this study was to determine the relative infectiousness of asymptomatic SARS-CoV-2 infected persons compared with symptomatic individuals based on a scoping review of available literature. Design Rapid scoping review of peer-reviewed literature from 1 January to 5 December 2020 using the LitCovid database and the Cochrane libr...

Background: There has been very little previous research in Ireland on the farmers' opinions regarding calf welfare issues. Calf welfare, particularly for male dairy calves, has assumed greater importance in Ireland in recent years due, in part, to an increase in the number of dairy cattle over the past decade. The objective of this study was to ex...

The ability to accurately identify infected hosts is the cornerstone of effective disease control and eradication programs. In the case of bovine tuberculosis, accurately identifying infected individual animals has been challenging as all available tests exhibit limited discriminatory ability. Here we assess the utility of two serological tests (ID...

Background Bovine tuberculosis (bTB) is a costly epidemiologically complex, multi-host, endemic disease. Lack of understanding of transmission dynamics may undermine eradication efforts. Pathogen whole genome sequencing improves epidemiological inferences, providing a means to determine the relative importance of inter- and intra- species host tran...

Bovine viral diarrhoea virus (BVDV) and border disease virus (BDV) can cause significant health problems in ruminants and economic impacts for farmers. The aim of this study was to evaluate pestivirus exposure in Northern Ireland sheep and goat flocks, and to compare findings with a previous study from the region. Up to 20 animals were sampled fro...

Decisions around animal health management by stakeholders are often subject to resource limitation, therefore prioritization processes are required to evaluate whether effort is attributed appropriately. The objectives of this study were to develop and apply a surveillance prioritization process for animal health surveillance activities in Ireland....

There are a paucity of data quantifying on-farm management practices such as the frequency of intraherd cattle movements, use of consolidated or spatially fragmented grazing pastures, and duration of time cattle spend at grass with respect to biosecurity and disease transmission. Such movement dynamics are important when attempting to understand th...

Post-mortem surveillance in Ireland discloses skin-test negative cattle with presumptive evidence of infection of Mycobacterium bovis (lesions at routine slaughter (LRS)), the causative agent of bovine tuberculosis (bTB). Laboratory confirmation of lesions has impacts on trade restrictions for herds, therefore if laboratory capacity was diminished,...

The serial interval is the time between symptom onsets in an infector–infectee pair. The generation time, also known as the generation interval, is the time between infection events in an infector–infectee pair. The serial interval and the generation time are key parameters for assessing the dynamics of a disease. A number of scientific papers repo...

The COVID-19 pandemic, a singular disruptive event in recent human history, has required rapid, innovative, coordinated and collaborative approaches to manage and ameliorate its worst impacts. However, the threat remains, and learning from initial efforts may benefit the response management in the future. One Health approaches to managing health ch...

Bovine tuberculosis (bTB) outbreaks, caused by Mycobacterium bovis infection, are a costly animal health challenge. Understanding factors associated with the duration of outbreaks, known as breakdowns, could lead to better disease management policy development. We undertook a retrospective observational study (2012–2018) and employed Finite Mixture...

Bovine tuberculosis (bTB) can be spread between and among cattle and wildlife hosts e.g. European badger (Meles meles). The majority of cattle in the UK and Ireland are grazed during the summer, potentially exposing them to Mycobacterium bovis. 18 farms were surveyed (39% dairy, 61% beef; fields n = 697) for one grazing season (May-November 2016, n...

Reactivation of latent Gammaherpesvirus in the genital tract can lead to reproductive failure in domestic animals. Nevertheless, this pathophysiology has not received formal study in wild mammals. High prevalence of Mustelid gammaherpesvirus 1 (MusGHV-1) DNA detected in the genital tracts of European badgers (Meles meles) implies that this common p...

Bovine tuberculosis (bTB) outbreaks, caused by Mycobacterium bovis infection, are a costly animal health challenge. Understanding factors associated with the duration of outbreaks, known as breakdowns, could lead to better disease management policy development. We undertook a retrospective observational study (2012-2018) and employed Finite Mixture...

Objectives: The aim of this study was to conduct a scoping review of estimates of the relative infectiousness of asymptomatic persons infected with SARS-CoV-2 compared with symptomatic individuals. Design: Rapid scoping review of literature available until 8th April 2020. Setting: International studies on the infectiousness of individuals infected...

Background The transmissibility of SARS-CoV-2 determines both the ability of the virus to invade a population and the strength of intervention that would be required to contain or eliminate the spread of infection. The basic reproduction number, R 0 , provides a quantitative measure of the transmission potential of a pathogen. Objective Conduct a...

Bovine tuberculosis surveillance in Northern Ireland includes Multiple-Locus Variable number tandem repeat Analysis (MLVA) to determine the Mycobacterium bovis genetic type present in both cattle and the predominant wildlife host, the European badger (Meles meles). These data are useful for investigating clusters of infection and understanding the...

Bovine tuberculosis surveillance in Northern Ireland includes Multiple-Locus Variable 20 number tandem repeat Analysis (MLVA) to determine the Mycobacterium bovis genetic type present 21 in both cattle, and the predominant wildlife host, the European badger (Meles meles). These data are 22 informative for investigating clusters of infection and und...

Bovine tuberculosis (bTB), caused by Mycobacterium bovis, remains an endemic pathogen of significant socio-economic impact within the Republic of Ireland. The control of the pathogen is complex due to the chronic nature of infection, the characteristics and performance of available tests, and the presence of wildlife hosts. In Ireland, the primary...

Objectives Coronavirus disease (COVID-19) caused by the SARS-CoV-2 virus is spreading rapidly worldwide and threatening the collapse of national health care systems. The development of effective resource models are critical for long term health planning. The aim was to evaluate the available literature, to consider parameters affecting hospital res...

Background: Understanding the extent of virus transmission that can occur before symptom onset is vital for targeting control measures against the global pandemic of COVID-19. Objective: Estimation of (1) the proportion of pre-symptomatic transmission of COVID-19 that can occur and (2) timing of transmission relative to symptom onset. Design: Secon...

Background: The serial interval is the time between symptom onsets in an infector infectee pair. The generation time, also known as the generation interval, is the time between infection events in an infector infectee pair. The serial interval and the generation time are key parameters for assessing the dynamics of a disease. A number of scientific...

Objectives: Our objective was to review the literature on the inferred duration of the infectious period of COVID-19, caused by SARS-COV-2 virus, and provide an overview of the variation depending on the methodological approach. Design: Rapid scoping review. Literature review with fixed search terms, up to 1st April 2020. Central tendency and varia...

Background: Reliable estimates of the incubation period are important for decision making around the control of infectious diseases. Knowledge of the incubation period distribution can be used directly to inform decision-making or as inputs into mathematical models. Objectives: The aim of this study was to conduct a rapid systematic review and meta...

The colonization of Ireland by mammals has been the subject of extensive study using genetic methods and forms a central problem in understanding the phylogeography of European mammals after the Last Glacial Maximum. Ireland exhibits a depauperate mammal fauna relative to Great Britain and continental Europe, and a range of natural and anthropogeni...

Bovine tuberculosis (BTB) remains as a costly disease of cattle-herds in the Republic of Ireland (ROI). And, this persistence is partially attributable to the presence of M. bovis infection, in a wildlife reservoir, the European badger (Meles meles). Thus, both area-wide and limited-area targeted-badger-culling have been part of the ROI-BTB control...

Background Despite rigorous controls placed on herds which disclose ante-mortem test positive cattle to bovine tuberculosis, caused by the infection of Mycobacterium bovis , many herds in Northern Ireland (NI) experience prolonged breakdowns. These herds represent a considerable administrative and financial burden to the State and farming community...