scholarly journals Future Risk of Bovine Tuberculosis (Mycobacterium bovis) Breakdown in Cattle Herds 2013–2018: A Dominance Analysis Approach

2021 ◽  
Vol 9 (5) ◽  
pp. 1004
Author(s):  
Andrew W. Byrne ◽  
Damien Barrett ◽  
Philip Breslin ◽  
Jamie M. Madden ◽  
James O’Keeffe ◽  
...  
Keyword(s):  
Bovine Tuberculosis ◽  
Policy Development ◽  
Strong Predictor ◽  
Herd Size ◽  
Analysis Approach ◽  
Dominance Analysis ◽  
Control Programmes ◽  
Significant Spatial Variation ◽  
Future Risk ◽  
Cattle Herds

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 contribute to tailored management and policies. Here, we estimated the future risk of herd BD for the cohort of herds that were derestricted during 2013 in Ireland using multivariable logit regression models, with a dominance analysis approach. One third of herds that were derestricted in 2013 experienced a breakdown during the follow-up five year period (1469/4459; 33%). BD length was a significant predictor of future risk, primarily driven by long BDs > 230 days relative to short BDs < 130 days (OR 95%CI: 1.157–1.851), as was having had a previous BD (OR 95%CI: 1.012–1.366). Herd-size was the dominant predictor of future risk (accounted for 46% of predicted variance), suggesting significant increase in risk of future breakdown with increasing (log) herd-size (OR 95%CI: 1.378–1.609). There was significant spatial variation in future risk across counties, and it was the second most dominant predictor of future risk (25% of predicted variance). The size of index breakdowns was not a strong predictor of future risk over a 5-year period. These findings can inform a risk-based policy development.

Characteristics of Northern Irish cattle herds without bovine tuberculosis infection

2019 ◽  
Vol 184 (25) ◽  
pp. 772-772
Author(s):  
Georgina Milne ◽  
Jordon Graham ◽  
Adrian R Allen ◽  
Angela Lahuerta-Marin ◽  
Carl M McCormick ◽  
...  
Keyword(s):  
Bovine Tuberculosis ◽  
Disease Status ◽  
Herd Size ◽  
Case Control ◽  
Control Analysis ◽  
Northern Irish ◽  
Retrospective Case ◽  
Targeted Interventions ◽  
Cattle Herds ◽  
Case Control Analysis

BackgroundDespite ongoing eradication efforts, bovine tuberculosis (bTB) is endemic in cattle herds in Northern Ireland (NI). This disease has serious implications for the economy, farming and animal welfare. Previous research identified a population of herds which have remained free from bTB infection for 10 years (2004–2014). Understanding the characteristics of these herds may have important implications for eradication efforts, such as spatially targeted interventions.MethodsA cluster analysis and a retrospective case–control analysis was conducted to compare bTB- free herds with herds which experienced prolonged infection (ie, bTB breakdowns lasting more than ≥ 365 days).ResultsOnly small, localised clusters of herds which have remained free from bTB were revealed, thus limiting the potential for spatially targeted interventions. The results illustrated the importance of herd size to disease status; over 27 per cent of the bTB-free herds had up to 10 animals. However, the data also showed that there were no inward movements in the year before the bTB skin test in those herds which remained free from bTB.ConclusionsAttention should therefore be given to the cattle movement network in NI to better understand the risk associated with cattle purchasing.

scholarly journals Herd-Level Risk Factors for Bovine Tuberculosis: A Literature Review

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Robin A. Skuce ◽  
Adrian R. Allen ◽  
Stanley W. J. McDowell
Keyword(s):  
Risk Factors ◽  
Bovine Tuberculosis ◽  
Management Practices ◽  
Scientific Evidence ◽  
Epidemiological Studies ◽  
Herd Size ◽  
Herd Level ◽  
Endemic Diseases ◽  
Veterinary Profession ◽  
Cattle Herds

Bovine tuberculosis (TB), caused byMycobacterium bovis, is one of the most challenging endemic diseases currently facing government, the veterinary profession, and the farming industry in the United Kingdom and Ireland and in several other countries. The disease has a notoriously complex epidemiology; the scientific evidence supports both cattle-cattle and wildlife-cattle transmission routes. To produce more effective ways of reducing such transmission, it is important to understand those risk factors which influence the presence or absence of bovine TB in cattle herds. Here we review the literature on herd-level risk factor studies. Whilst risk factors operate at different scales and may vary across regions, epidemiological studies have identified a number of risk factors associated with bovine TB herd breakdowns, including the purchase of cattle, the occurrence of bovine TB in contiguous herds, and/or the surrounding area as well as herd size. Other factors identified in some studies include farm and herd management practices, such as, the spreading of slurry, the use of certain housing types, farms having multiple premises, and the use of silage clamps. In general, the most consistently identified risk factors are biologically plausible and consistent with known transmission routes involving cattle-cattle and wildlife-cattle pathways.

A simulation model for the spread of bovine tuberculosis within New Zealand cattle herds

1997 ◽  
Vol 32 (1-2) ◽  
pp. 57-75 ◽  
Author(s):  
N.D. Barlow ◽  
J.M. Kean ◽  
G. Hickling ◽  
P.G. Livingstone ◽  
A.B. Robson
Keyword(s):  
New Zealand ◽  
Simulation Model ◽  
Bovine Tuberculosis ◽  
Cattle Herds

scholarly journals Bovine Tuberculosis (Mycobacterium bovis) Outbreak Duration in Cattle Herds in Ireland: A Retrospective Observational Study

Pathogens ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 815
Author(s):  
Andrew W. Byrne ◽  
Damien Barrett ◽  
Philip Breslin ◽  
Jamie M. Madden ◽  
James O'Keeffe ◽  
...  
Keyword(s):  
Risk Factors ◽  
Observational Study ◽  
Mycobacterium Bovis ◽  
Bovine Tuberculosis ◽  
Animal Health ◽  
Herd Size ◽  
Policy Formation ◽  
Nitrogen Loading ◽  
Management Policy ◽  
Retrospective Observational Study

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 Models (FMM) to model the outcome parameter, and to investigate how factors were associated with duration for differing subpopulations identified. In addition to traditional risk factors (e.g., herd size, bTB history), we also explored farm geographic area, parcels/farm fragmentation, metrics of intensity via nitrogen loading, and whether herds were designated controlled beef finishing units (CBFU) as potential risk factors for increased duration. The final model fitted log-normal distributions, with two latent classes (k) which partitioned the population into a subpopulation around the central tendency of the distribution, and a second around the tails of the distribution. The latter subpopulation included longer breakdowns of policy interest. Increasing duration was positively associated with recent (<3 years) TB history and the number of reactors disclosed, (log) herd size, beef herd-type relative to other herd types, number of land parcels, area, being designated a CBFU (“feedlot”) and having high annual inward cattle movements within the “tails” subpopulation. Breakdown length was negatively associated with the year of commencement of breakdown (i.e., a decreasing trend) and non-significantly with the organic nitrogen produced on the farm (N kg/hectare), a measure of stocking density. The latter finding may be due to confounding effects with herd size and area. Most variables contributed only moderately to explaining variation in breakdown duration, that is, they had moderate size effects on duration. Herd-size and CBFU had greater effect sizes on the outcome. The findings contribute to evidence-based policy formation in Ireland.

scholarly journals Wild boar (Sus scrofa) as a possible vector of mycobacterial infections: review of literature and critical analysis of data from Central Europe between 1983 to 2001

2012 ◽  
Vol 48 (No. 3) ◽  
pp. 51-65 ◽  
Author(s):  
M. Machackova ◽  
L. Matlová ◽  
J. Lamka ◽  
J. Smolík ◽  
IMelicharek ◽  
...  
Keyword(s):  
Wild Boar ◽  
Central Europe ◽  
Cervus Elaphus ◽  
Bovine Tuberculosis ◽  
Sus Scrofa ◽  
Hawaiian Island ◽  
Brushtail Possum ◽  
Mycobacterial Infections ◽  
Control Programmes ◽  
In The Wild

Infected animals in the wild, which can act as a reservoir and/or vector for the origin of bovine tuberculosis, are a great problem for national programmes seeking to free herds of cattle from the infection. The circulation of Mycobacterium bovis in the wild animal population might cause a slow-down in the progress of control programmes through the reinfection of herds of livestock. The Eurasian badger (Meles meles) and red deer (Cervus elaphus) living in the wild in Great Britain and Ireland, brushtail possum (Trichosurus vulpecula), ferrets (Mustela putorius f. furo) in New Zealand and wild buffalo (Bubalus arnee) in Australia are among already known reservoirs and vectors of bovine tuberculosis. In 7 countries of Central Europe (Bosnia and Herzegovina, Croatia, Czech Republic, Hungary, Poland, Slovakia and Slovenia) bovine tuberculosis in ca􀄴le was controlled as part of national control programmes more than 20 years ago. In the last decade M. bovis has been diagnosed extremely sporadically in cattle and other domestic animals as well as in wild animals held in captivity or living in the wild. This favour&shy;able situation could be threatened by the mycobacteria spreading via the wild boar (Sus scrofa) which is susceptible to mycobacterial infection and very abundant in Central Europe. According to available literary data, mycobacteria were detected in 361 wild boar originating from countries other than those of Central Europe, such as Australia, Bulgaria, Germany, the Hawaiian island of Molokai, Italy and Spain. M. tuberculosis complex (33.9%) and M. bovis complex (39.8%) isolates were most frequently detected in the faeces and/or parenchymatous organs of wild boar. Of other mycobacterial species, M. intracellulare (3.8%), M. avium subsp. avium (3.8%), M. terrae (2.4%), M. fortuitum (2.2%), M. scrofulaceum (2.2%), M. gordonae (0.8%), M. simiae (0.5%), M. szulgai (0.5%), M. xenopi (0.5%), M. smegmatis (0.2%), M. vaccae (0.2%), fast-growing, further unspecified species (0.2%) and unidentified mycobacteria (8.8%) were isolated. Following the analysis of literary data and our own results, it was found that, in the area covered by the above-mentioned 7 countries of Central Europe, a total of 431 wild boar were examined for mycobacterial infections in the years 1983&ndash;2001. Tuberculous lesions in parenchymatous organs were found in 43 (10.0%) animals. M. bovis was identified in 22 (5.1%) animals, M. a. avium in 2 (0.4%), M. a. paratuberculosis in 1 (0.2%) animal and atypical mycobacteria in 27 (6.3%) animals. The wild boar may therefore represent, under certain unfavourable epizootio&shy;logical conditions, a vector of some mycobacterial infections in not only animals, but also humans.

scholarly journals Bovine tuberculosis and its risk factors among dairy cattle herds in and around Bahir Dar City, Northwest Ethiopia

2015 ◽  
Vol 19 (2) ◽  
pp. 27 ◽  
Author(s):  
Anwar Nuru ◽  
Gezahegne Mamo ◽  
Leakemariam Teshome ◽  
Aboma Zewdie ◽  
Girmay Medhin ◽  
...  
Keyword(s):  
Risk Factors ◽  
Dairy Cattle ◽  
Bovine Tuberculosis ◽  
Northwest Ethiopia ◽  
Bahir Dar ◽  
Cattle Herds

scholarly journals Assessment of the specificity of a gamma-interferon test performed with specific antigens to detect bovine tuberculosis, after non-negative results to intradermal tuberculin testing

2019 ◽  
Vol 6 (1) ◽  
pp. e000335 ◽  
Author(s):  
Anne Praud ◽  
Clémence Bourély ◽  
Maria-Laura Boschiroli ◽  
Barbara Dufour
Keyword(s):  
Bovine Tuberculosis ◽  
Gamma Interferon ◽  
Skin Tests ◽  
Negative Results ◽  
In Series ◽  
Specific Antigens ◽  
Ifn Γ ◽  
Tuberculin Testing ◽  
Cattle Herds ◽  
Higher Sensitivity

In cattle herds in France, cervical skin tests (STs) using simple intradermal tuberculin (SIT) are performed to detect bovine tuberculosis (bTB). When positive results are found on ST screening, the herd is considered to be ‘under suspicion’ and confined, raising economic issues. The suspicion can be lifted by carrying out a single intradermal cervical comparative test (SICCT) at least six weeks later.The authors conducted an experimental study in France between 2013 and 2015 to assess the accuracy of the gamma-interferon test (IFN-γ), used in series after a non-negative result to ST screening, and to study the possibility of replacing the SICCT performed six weeks later by an IFN performed within a few days. Data were collected concerning 40 infected and 1825 bTB-free animals from herds with non-negative results to ST screening. This study showed that the IFN-γ test based on specific antigens and performed within a few days of a non-negative result to the ST has higher sensitivity than the SICCT performed six weeks later and equal specificity. The IFN test is more convenient to perform; however, it is more expensive. The IFN-γ test based on MIX antigens may be a useful alternative to the SICCT, to shorten the confinement period of suspect herds without underdetecting bTB.

scholarly journals Effects of trading networks on the risk of bovine tuberculosis incidents on cattle farms in Great Britain

2020 ◽  
Vol 7 (4) ◽  
pp. 191806
Author(s):  
Helen R. Fielding ◽  
Trevelyan J. McKinley ◽  
Richard J. Delahay ◽  
Matthew J. Silk ◽  
Robbie A. McDonald
Keyword(s):  
Great Britain ◽  
Bovine Tuberculosis ◽  
Disease Risk ◽  
Herd Size ◽  
Risk Area ◽  
High Risk Area ◽  
Trading Patterns ◽  
Additional Approach ◽  
Trading Networks ◽  
Cattle Farms

Trading animals between farms and via markets can provide a conduit for spread of infections. By studying trading networks, we might better understand the dynamics of livestock diseases. We constructed ingoing contact chains of cattle farms in Great Britain that were linked by trading, to elucidate potential pathways for the transmission of infection and to evaluate their effect on the risk of a farm experiencing a bovine tuberculosis (bTB) incident. Our findings are consistent with variation in bTB risk associated with region, herd size, disease risk area and history of previous bTB incidents on the root farm and nearby farms. However, we also identified effects of both direct and indirect trading patterns, such that connections to more farms in the England High-Risk Area up to three movements away from the root farm increased the odds of a bTB incident, while connections with more farms in the England Low-Risk Area up to eight movements away decreased the odds. Relative to other risk factors for bTB, trading behaviours are arguably more amenable to change, and consideration of risks associated with indirect trading, as well direct trading, might therefore offer an additional approach to bTB control in Great Britain.

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