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13 result(s) for "Guelbenzu-Gonzalo, Maria"
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Epidemiology of age-dependent prevalence of Bovine Herpes Virus Type 1 (BoHV-1) in dairy herds with and without vaccination
Many studies report age as a risk factor for BoHV-1 infection or seropositivity. However, it is unclear whether this pattern refects true epidemiological causation or is a consequence of study design and other issues. Here, we seek to understand the age-related dynamics of BoHV-1 seroprevalence in seasonal calving Irish dairy herds and provide decision support for the design and implementation of efective BoHV-1 testing strategies. We analysed seroprevalence data from dairy herds taken during two Irish seroprevalence surveys conducted between 2010 and 2017. Age-dependent seroprevalence profles were constructed for herds that were seropositive and unvaccinated. Some of these profles revealed a sudden increase in seroprevalence between adjacent age-cohorts, from absent or low to close to 100% of seropositive animals. By coupling the outcome of our data analysis with simulation output of an individual-based model at the herd scale, we have shown that these sudden increases are related to extensive virus circulation within a herd for a limited time, which may then subsequently remain latent over the following years. BoHV-1 outbreaks in dairy cattle herds afect animals independent of age and lead to almost 100% seroconversion in all age groups, or at least in all animals within a single epidemiological unit. In the absence of circulating infection, there is a year-on-year increase in the age-cohort at which seroprevalence changes from low to high. The fndings of this study inform recommendations regarding testing regimes in the context of contingency planning or an eradication programme in seasonal calving dairy herds.
Combining expert knowledge and machine-learning to classify herd types in livestock systems
A detailed understanding of herd types is needed for animal disease control and surveillance activities, to inform epidemiological study design and interpretation, and to guide effective policy decision-making. In this paper, we present a new approach to classify herd types in livestock systems by combining expert knowledge and a machine-learning algorithm called self-organising-maps (SOMs). This approach is applied to the cattle sector in Ireland, where a detailed understanding of herd types can assist with on-going discussions on control and surveillance for endemic cattle diseases. To our knowledge, this is the first time that the SOM algorithm has been used to differentiate livestock systems. In compliance with European Union (EU) requirements, relevant data in the Irish livestock register includes the birth, movements and disposal of each individual bovine, and also the sex and breed of each bovine and its dam. In total, 17 herd types were identified in Ireland using 9 variables. We provide a data-driven classification tree using decisions derived from the Irish livestock registration data. Because of the visual capabilities of the SOM algorithm, the interpretation of results is relatively straightforward and we believe our approach, with adaptation, can be used to classify herd type in any other livestock system.
A Herd Investigation Tool in Support of the Irish Bovine Viral Diarrhoea Eradication Programme
Bovine viral diarrhoea (BVD) is an important endemic disease of cattle. In Ireland, an industry-led compulsory eradication programme began in January 2013. The main elements of this programme are the identification and elimination of persistently infected (PI) calves by testing all new-borns, the implementation of biosecurity to prevent re-introduction of disease and continuous surveillance. In 2016, a standardised framework was developed to investigate herds with positive results. This is delivered by trained private veterinary practitioners (PVP). The investigation's aims are 3-fold: firstly, to identify plausible sources of infection; secondly, to ensure that no virus-positive animals remain on farm by resolving the BVD status of all animals in the herd; and thirdly, agreeing up to three biosecurity measures with the herd owner to prevent the re-introduction of the virus. Each investigation follows a common approach comprising four steps based on information from the programme database and collected on-farm: firstly, identifying the time period when each virus-positive calf was exposed in utero (window of susceptibility, taken as 30–120 days of gestation); secondly, determining the location of the dam of each positive calf during this period; thirdly, to investigate potential sources of exposure, either within the herd or external to it; and finally, based on the findings, the PVP and herdowner agree to implement up to three biosecurity measures to minimise the risk of reintroduction. Between 2016 and 2020, 4,105 investigations were completed. The biosecurity recommendations issued more frequently related to the risks of introduction of virus associated with contact with neighbouring cattle at pasture, personnel (including the farmer), the purchase of cattle and vaccination. Although each investigation generates farm-specific outcomes and advice, the aggregated results also provide an insight into the most commonly identified transmission pathways for these herds which inform overall programme communications on biosecurity. The most widely identified plausible sources of infection over these years included retained BVD-positive animals, Trojan births, contact at boundaries and indirect contact through herd owner and other personnel in the absence of appropriate hygiene measures. While generated in the context of BVD herd investigations, the findings also provide an insight into biosecurity practises more generally on Irish farms.
Prevalence and risk factors for Bovine Herpesvirus Type 1 (BoHV-1) infection in Irish beef herds: results from the National Beef Welfare Scheme 2023
Infectious bovine rhinotracheitis (IBR), caused by bovine herpesvirus-1 (BoHV-1), is a highly contagious disease with significant economic impacts on the cattle industry. It can also lead to respiratory distress, reproductive losses and compromised animal welfare, and thus represents a key target for control. This study aimed to assess the prevalence and identify risk factors associated with BoHV-1 infection in Irish beef herds. Conducted under the National Beef Welfare Scheme (NBWS), the study involved testing 10,659 beef breeding herds, representing approximately 20% of the national beef herd population. A total of 189,404 animals were tested. Using a ‘snapshot’ testing strategy herd-level BoHV-1 status was determined based on the presence of antibodies to the gE glycoprotein in up to 20 randomly selected animals, preferably over 9 months of age to exclude maternally derived antibodies. Vaccination histories were not available for participating herds. Results indicated an animal-level apparent prevalence of 11.4% and a herd-level apparent prevalence based on positive snapshots of 48.8% (defined as herds with ≥ 1 positive animal). Larger herds and high rates of animal in-moves per capita (here, > 17% of herd replaced by purchases in the past year) were identified as significant risk factors for recent (within the last three years) BoHV-1 circulation. Previous studies had indicated a herd-level prevalence in Ireland of up to 80%. The lower prevalence estimates identified in this study may reflect improved biosecurity and vaccination uptake in recent years. The findings from this survey, although showing that BoHV-1 is still endemic in Irish beef herds, provide updated prevalence figures which are considerably lower, indicating that a higher number of farms would be in a position to achieve freedom from BoHV-1 in a relatively short period. These results offer essential epidemiological insights to inform the design and implementation of a national BoHV-1 control programme in Ireland.
No evidence of BoHV-1 exposure and low levels of pestivirus exposure in sera from 116 opportunistically sampled wild deer in Northern Ireland
Bovine Viral Diarrhoea Virus (BVDV), Border Disease Virus (BDV), and Bovine Herpesvirus-1 (BoHV-1, the cause of Infectious Bovine Rhinotracheitis, IBR), are economically important endemic viruses in ruminant livestock in the United Kingdom and Ireland. Deer could undermine control efforts in livestock by contributing to virus transmission and maintenance, but information on the presence of these viruses in the wild deer population is lacking. Blood samples from wild fallow and sika deer culled in Northern Ireland were collected opportunistically in the 2022–23 hunting season and tested using enzyme-linked immunosorbent assay (ELISA) for the presence of antibodies to these viruses ( n  = 116). No antibodies against BoHV-1 were detected. Antibodies against pestivirus were detected in three samples (2.6%), all from sika deer, and constitute the first report in this species in Europe. Virus strain differentiation by virus neutralization test (VNT) was inconclusive. Results therefore indicate no evidence of exposure to BoHV-1 and very low levels of pestivirus exposure in these deer populations. Based on these results there are currently no grounds to implicate deer as significant wildlife reservoirs of these viruses.
Bovine tuberculosis visible lesions in cattle culled during herd breakdowns: the effects of individual characteristics, trade movement and co-infection
Background Bovine tuberculosis (bTB), caused by Mycobacterium bovis , remains a significant problem for livestock industries in many countries worldwide including Northern Ireland, where a test and slaughter regime has utilised the Single Intradermal Comparative Cervical Tuberculin (SICCT) test since 1959. We investigated the variation in post-mortem confirmation based on bTB visible lesion (VL) presence during herd breakdowns using two model suites. We investigated animal-level characteristics, while controlling for herd-level factors and clustering. We were interested in potential impacts of concurrent infection, and therefore we assessed whether animals with evidence of liver fluke infection ( Fasciola hepatica ; post-mortem inspection), M. avium reactors (animals with negative M. bovis-avium ( b-a ) tuberculin reactions) or Bovine Viral Diarrhoea Virus (BVDV; RT-PCR tested) were associated with bTB confirmation. Results The dataset included 6242 animals removed during the 14 month study period (2013–2015). bTB-VL presence was significantly increased in animals with greater b-a reaction size at the disclosing SICCT test (e.g. b-a  = 5-9 mm vs. b-a =  0 mm, adjusted Odds ratio (aOR): 14.57; p  < 0.001). M. avium reactor animals ( b-a  < 0) were also significantly more likely to disclose VL than non-reactor animals ( b-a =  0; aOR: 2.29; p  = 0.023). Animals had a greater probability of exhibiting lesions with the increasing number of herds it had resided within (movement; log-herds: aOR: 2.27–2.42; p  < 0.001), if it had an inconclusive penultimate test result (aOR: 2.84–3.89; p  < 0.001), and with increasing time between tests (log-time; aOR: 1.23; p  = 0.003). Animals were less likely to have VL if they were a dairy breed (aOR: 0.79; p  = 0.015) or in an older age-class (e.g. age-quartile 2 vs. 4; aOR: 0.65; p  < 0.001). Liver fluke or BVDV variables were not retained in either multivariable model as they were non-significantly associated with bTB-VL status ( p  > 0.1). Conclusions Our results suggest that neither co-infection of liver fluke nor BVDV had a significant effect on the presence of VLs in this high-risk cohort. M. avium tuberculin reactors had a significantly increased risk of disclosing with a bTB lesion, which could be related to the impact of co-infection with M. avium subsp. paratuberculosis (MAP) affecting the performance of the SICCT however further research in this area is required. Movements, test history, breed and age were important factors influencing confirmation in high-risk animals.
The Irish cattle population structured by enterprise type: overview, trade & trends
Background The cattle sector is the most important economic production unit of the Irish farming and agri-food sector. Despite its relevance, there has been limited quantitative information about the structure of differing cattle production types and of the connections between them. This paper addresses this gap by providing, for the first time, an overview of the Irish cattle population structured by enterprise type. Methods & Results We collected data from the cattle register for the period 2015 to 2019 and assigned registered herds to one of 18 different herd types using a recently published herd type classification approach. This allows, for the first time, to exploring changes in enterprise types and subtypes over time, and describing the movements between these subtypes and from these subtypes to slaughter. Conclusions The overview and associated classification presented in this study will form the basis for a number of future comparative studies, including cross-sectoral assessments of profitability, estimation of the extent of animal health losses on Irish cattle farms or structural analysis of Greenhouse Gas (GHG) emissions across production systems.
Trends in Salmonella serovars and antimicrobial resistance in pigs and poultry in Northern Ireland between 1997 and 2016
BackgroundIn the EU, salmonellosis is the second most commonly reported zoonosis. This pattern is reflected in Northern Ireland. Historically, foodborne salmonellosis has largely been attributed to the consumption of poultry products, and as such a number of legislative measures have been introduced by the EC. These policies focus mainly on five target Salmonella serovars.MethodsHere the authors present a descriptive analysis of 20 years of data from the Northern Ireland National Reference Laboratory for Salmonella.ResultsThe study’s results show, for poultry submissions, a large decrease in the detection of four of the five targeted Salmonella serovars over the study period, with the fifth serovar undetected throughout the study. Additionally, there was an increase in the detection of a number of other non-regulated serovars. In pigs, S Typhimurium, which is among the most common causes of human salmonellosis, was the most commonly isolated serovar. When comparing levels of antimicrobial resistance in S Typhimurium between livestock groups, the authors found a decrease over time in poultry, but an increase in pigs, highlighting the potential significance of pigs in addressing public health concerns.ConclusionThe authors conclude that continued surveillance is important in the assessment of control measures at a national and transnational scale.
Is There a Relationship Between Bovine Tuberculosis (bTB) Herd Breakdown Risk and Mycobacterium avium subsp. paratuberculosis Status? An Investigation in bTB Chronically and Non-chronically Infected Herds
Bovine tuberculosis (bTB; ) remains a significant problem in a number of countries, and is often found where subsp. (MAP) is also present. In the United Kingdom, bTB has been difficult to eradicate despite long-term efforts. Co-infection has been proposed as one partial mechanism thwarting eradication. A retrospective case-control study of 4,500 cattle herds in Northern Ireland, where serological testing of cattle for MAP, was undertaken (2004-2015). Blood samples were ELISA tested for MAP; infection of was identified in herds by the comparative tuberculin test (CTT) and through post-mortem evidence of infection. Case-herds were those experiencing a confirmed bTB breakdown; control-herds were not experiencing a breakdown episode at the time of MAP testing. A second model included additional testing data of feces samples (culture and PCR results) to better inform herd MAP status. Multi-level hierarchical models were developed, controlling for selected confounders. A sensitivity analysis of the effect of MAP sample numbers per event and the prior timing of tuberculin-testing was undertaken. 45.2% ( = 250) of case observations and 36.0% (3,480) of control observations were positive to MAP by ELISA (45.8% and 36.4% when including ancillary fecal testing, respectively). Controlling for known confounders, the adjusted odds ratio (aOR) for this association was 1.339 (95%CI:1.085-1.652; including ancillary data aOR:1.356;95%CI:1.099-1.673). The size-effect of the association increased with the increasing number of samples per event used to assign herd MAP status (aOR:1.883 at >2 samples, to aOR:3.863 at >10 samples), however the estimated CI increased as decreased. 41.7% of observations from chronic herds were MAP serology-positive and 32.2% from bTB free herds were MAP positive (aOR: 1.170; 95%ci: 0.481-2.849). Cattle herds experiencing a bTB breakdown were associated with increased risk of having a positive MAP status. Chronic herds tended to exhibit higher risk of a positive MAP status than bTB free herds, however there was less support for this association when controlling for repeated measures and confounding. MAP co-infection may be playing a role in the success of bTB eradiation schemes, however further studies are required to understand the mechanisms and to definitively establish causation.
An Overview of Current Approaches and Challenges to the Control of Endemic Infectious Cattle Diseases in Albania
Agriculture is an important production sector in Albania that makes a significant contribution to the gross domestic product (GDP) and employment. The livestock sector contributes more than half of the agricultural GDP. The Albanian cattle population represents 50% of the total livestock units and accounts for 85% of the national milk production, the rest being supplied by small ruminants. Cattle productivity, health and welfare are hindered by infectious diseases, some of which are also transmissible to humans (zoonosis). The aim of this manuscript is to provide an overview of the control of selected regulated and non-EU regulated cattle diseases in Albania and to highlight specific challenges for the Albanian cattle industry. The most important infectious cattle diseases in Albania for which national control and eradication strategies are in place are bovine brucellosis, bovine tuberculosis, and anthrax, which are all zoonotic. Additionally, lumpy skin disease recently emerged in the Balkan region and is currently subject to controls. Most of the available funds and European Union support are allocated to the control of EU regulated zoonotic diseases. For control of non-EU regulated cattle diseases, no funds are available resulting in the lack of national control programmes (CPs). Based on research, clinical investigations and laboratory results, several non-EU regulated cattle infectious diseases appear endemic in Albanian dairy farms. While no national CPs exist for any of them, regional initiatives are available on a voluntary basis to control infectious bovine rhinotracheitis and bovine viral diarrhea. In the voluntary CPs, there is no monitored requirement to prove disease freedom of purchased animals and to re-evaluate the herd's free status after the introduction of animals into a herd. Data on animal movements that are routinely collected could potentially be used to control the risk of purchase, but quality needs to be further improved to increase its usefulness in disease CPs. This overview aims to collate existing information on the CPs implemented in Albania and to evaluate these to highlight gaps and threats in disease control, as well as opportunities and strengths through a SWOT (Strengths, Weaknesses, Opportunities, and Threats) analysis, with the goal of providing a framework for the future implementation of animal disease control measures in Albania.