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Brunton L, Enticott G. Is badger culling associated with risk compensation behaviour among cattle farmers? Vet Rec 2024; 194:e4152. [PMID: 38808965 DOI: 10.1002/vetr.4152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 03/19/2024] [Accepted: 04/05/2024] [Indexed: 05/30/2024]
Abstract
BACKGROUND Risk compensation theory suggests that behaviours are modified in response to interventions that remove risks by substituting them with other risky behaviours to maintain a 'risk equilibrium'. Alternatively, risk reduction interventions may result in spill-over behaviours that seek to minimise risks further. This paper assessed evidence for these behavioural risk responses among farmers in response to badger culling that seeks to remove the risk of bovine tuberculosis in cattle. METHODS Data from the UK's randomised badger culling trial were re-analysed, comparing farmers' cattle movement practices in proactive and reactive culling areas and control areas. Analysis compared cattle movements during and after the trial using zero-inflated negative binomial regression. RESULTS The analysis found no strong evidence of risk compensation behaviours among farmers who experienced proactive culling. However, strong evidence for a reduction in cattle movements in reactive culling areas was found. The results indicate high levels of inertia within farming systems in relation to cattle purchasing. LIMITATIONS Data do not account for the risk of cattle purchases and reflect previous policy regimens. Evidence from recent badger culling interventions should be analysed. CONCLUSION Proactive badger culling was not associated with risk compensation behaviours, while reactive badger culling was associated with decreased risk taking among farmers.
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Affiliation(s)
- Lucy Brunton
- Veterinary Epidemiology, Economics and Public Health Group, Royal Veterinary College, Hatfield, UK
| | - Gareth Enticott
- School of Geography and Planning, Cardiff University, Cardiff, UK
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2
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Pozo P, Isla J, Asiain A, Navarro D, Gortázar C. Contribution of herd management, biosecurity, and environmental factors to the risk of bovine tuberculosis in a historically low prevalence region. Animal 2024; 18:101105. [PMID: 38417216 DOI: 10.1016/j.animal.2024.101105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 01/30/2024] [Accepted: 02/01/2024] [Indexed: 03/01/2024] Open
Abstract
Eradication of bovine tuberculosis (bTB) in certain historically low-prevalence regions remains elusive. A complete characterisation of the husbandry practices, biosecurity, and environment where farms are located is crucial to implement targeted in-farm risk mitigation protocols. Here, a detailed survey performed in 94 dairy cattle farms located in Navarra, a low-prevalence region of Spain between 2016 and 2020 was carried out. Data on 73 biosecurity, farm-, and environmental-level factors potentially associated with the risk of bTB occurrence were evaluated using an ordinal logistic regression model: farms were classified based on their prevalence index, a score linked to each farm to account for the severity and recurrence of bTB cases: 22.3% of the farms had a score of 1, 21.3% a score of 2, 26.6% a score of ≥ 3, and 29.8% were negative herds. A statistically significant association between a higher prevalence index and the frequency of badger sightings along with the lease of pastures to sheep during Winter was identified. Farms that detected badgers on a monthly to daily basis in the surroundings and those that leased pastures for sheep flocks during Winter were four [odds ratio, 95% CI (4.3; 1.1-17.5)] and three (3.1; 1.0-9.9) times more likely to have the highest prevalence index, respectively (predicted probabilityprevalence index≥3 = 0.7; 95% CI 0.3-0.9). Conversely, farms that used a vehicle to transport animals from holdings to pastures were less likely (0.1; <0.1-0.3) to present higher levels of prevalence index compared with farms that used none (on foot). Results suggested that the combined effect of farm- and environmental-level risk factors identified here may be hampering disease eradication in Navarra, highlighting the need to implement targeted protocols on farms and grazing plots. An increased awareness of monitoring sheep and wildlife in direct or indirect contact with cattle herds in historically low bTB prevalence areas should be raised.
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Affiliation(s)
- P Pozo
- Grupo SaBio. Instituto de Investigación en Recursos Cinegéticos, IREC. CSIC-UCLM, 13071 Ciudad Real, Spain.
| | - J Isla
- Sabiotec. Edificio Polivalente UCLM, local 1.22, UCLM, 13005 Ciudad Real, Spain
| | - A Asiain
- Sección de Sanidad Animal. Departamento de Desarrollo Rural y Medio Ambiente. Gobierno de Navarra, 31002 Pamplona, Spain
| | - D Navarro
- Negociado de Epizootiología-Servicio de Ganadería. Departamento de Desarrollo Rural y Medio Ambiente. Gobierno de Navarra, 31002 Pamplona, Spain
| | - C Gortázar
- Grupo SaBio. Instituto de Investigación en Recursos Cinegéticos, IREC. CSIC-UCLM, 13071 Ciudad Real, Spain
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Hussein HA, Ahmed JM, Musse AH, Gizaw Y. Prevalence and risk factors of bovine tuberculosis in cattle in selected districts of Fafan pastoral settings, Eastern Ethiopia. Heliyon 2024; 10:e24998. [PMID: 38312611 PMCID: PMC10835366 DOI: 10.1016/j.heliyon.2024.e24998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 12/16/2023] [Accepted: 01/18/2024] [Indexed: 02/06/2024] Open
Abstract
Cross-sectional study was conducted from October 2021 to August 2022 to investigate the prevalence and associated risk factors of bovine tuberculosis in cattle in selected districts of the pastoral settings of Fafan zone, Somali region, eastern Ethiopia. A comparative intradermal tuberculin test was performed using purified protein derivatives. Animal-related characteristics, and the owner's knowledge on the importance of BTB were collected using a structured questionnaire. The prevalence was 11.24 % (95 % CI, 8.61-14.35) and 43.3 % (95 % CI, 33.27-53.75) at the individual and herd levels, respectively. There were statistically significant differences in the proportions of positive reactor animals according to body condition score (P = 0.000), age (P = 0.048), seasonal migration (P = 0.038), parity number (P = 0.005), and reproductive status (P = 0.037). Animals with poor body condition scores had a significantly higher likelihood of testing positive, with their odds being 11.4 times greater (COR = 11.408, CI = 3.43-37.94, P < 0.001). In multivariate logistic regression, poor body condition score remained significantly associated with the odds of a positive reaction to tuberculosis (AOR = 0.137, CI = 0.053-0.356, P < 0.001). Similarly, the analysis showed that seasonal migration (AOR = 2.882, CI = 1.155-7.191, P = 0.023) and parity number (AOR = 11.64, CI = 1.818-74.464, P = 0.010) were significant predictors of bovine tuberculosis infection in cattle. According to the questionnaire, 14.2 % (17 of 120) and 13.3 % (16 of 120) of the respondents were knowledgeable about bovine tuberculosis and its transmission from animals to humans, and vice versa, respectively. The general judgment of herders' understanding of bovine tuberculosis transmission methods to humans was very low. The study findings showed a high prevalence of bovine tuberculosis in the study area, emphasizing the need for an effective control and prevention strategy.
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Affiliation(s)
- Hassan Abdi Hussein
- College of Veterinary Medicine, Department of One Health, Jigjiga University, P.O. Box, 1020, Jigjiga, Ethiopia
| | - Juhar Mohamed Ahmed
- College of Veterinary Medicine, Department of One Health, Jigjiga University, P.O. Box, 1020, Jigjiga, Ethiopia
| | - Abdi Hussein Musse
- College of Veterinary Medicine, Department of One Health, Jigjiga University, P.O. Box, 1020, Jigjiga, Ethiopia
| | - Yonas Gizaw
- College of Agriculture and Environmental Science, Arsi University, P.O. Box, 193, Asella, Ethiopia
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Byrne AW, Barrett D, Breslin P, Fanning J, Casey M, Madden JM, Lesellier S, Gormley E. Bovine tuberculosis in youngstock cattle: A narrative review. Front Vet Sci 2022; 9:1000124. [PMID: 36213413 PMCID: PMC9540495 DOI: 10.3389/fvets.2022.1000124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 08/30/2022] [Indexed: 11/26/2022] Open
Abstract
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 epidemiology to M. bovis in youngstock (up to 1-year of age). Youngstock are susceptible to M. bovis infection when exposed, with the capacity to develop typical bTB lesions. Calves can be exposed through similar routes as adults, via residual infection, contiguous neighborhood spread, wildlife spillback infection, and the buying-in of infected but undetected cattle. Dairy systems may lead to greater exposure risk to calves relative to other production systems, for example, via pooled milk. Given their young age, calves tend to have shorter bTB at-risk exposure periods than older cohorts. The detection of bTB varies with age when using a wide range of ante-mortem diagnostics, also with post-mortem examination and confirmation (histological and bacteriological) of infection. When recorded as positive by ante-mortem test, youngstock appear to have the highest probabilities of any age cohort for confirmation of infection post-mortem. They also appear to have the lowest false negative bTB detection risk. In some countries, many calves are moved to other herds for rearing, potentially increasing inter-herd transmission risk. Mathematical models suggest that calves may also experience lower force of infection (the rate that susceptible animals become infected). There are few modeling studies investigating the role of calves in the spread and maintenance of infection across herd networks. One study found that calves, without operating testing and control measures, can help to maintain infection and lengthen the time to outbreak eradication. Policies to reduce testing for youngstock could lead to infected calves remaining undetected and increasing onwards transmission. Further studies are required to assess the risk associated with changes to testing policy for youngstock in terms of the impact for within-herd disease control, and how this may affect the transmission and persistence of infection across a network of linked herds.
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Affiliation(s)
- Andrew W. Byrne
- One-Health and Welfare Scientific Support Unit, National Disease Control Centre, Department of Agriculture, Food and the Marine, Dublin, Ireland
- *Correspondence: Andrew W. Byrne ;
| | - Damien Barrett
- One-Health and Welfare Scientific Support Unit, National Disease Control Centre, Department of Agriculture, Food and the Marine, Dublin, Ireland
- ERAD, Department of Agriculture, Food and the Marine, Dublin, Ireland
| | - Philip Breslin
- ERAD, Department of Agriculture, Food and the Marine, Dublin, Ireland
| | - June Fanning
- One-Health and Welfare Scientific Support Unit, National Disease Control Centre, Department of Agriculture, Food and the Marine, Dublin, Ireland
| | - Miriam Casey
- Centre for Veterinary Epidemiology and Risk Analysis (CVERA), School of Veterinary Medicine, University College Dublin (UCD), Dublin, Ireland
| | - Jamie M. Madden
- Centre for Veterinary Epidemiology and Risk Analysis (CVERA), School of Veterinary Medicine, University College Dublin (UCD), Dublin, Ireland
| | - Sandrine Lesellier
- Nancy Laboratory for Rabies and Wildlife (LRFSN), ANSES, Technopole Agricole et Vétérinaire, Malzéville, France
| | - Eamonn Gormley
- Tuberculosis Diagnostics and Immunology Research Laboratory, School of Veterinary Medicine, University College Dublin (UCD), Dublin, Ireland
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Milne G, Graham J, McGrath J, Kirke R, McMaster W, Byrne AW. Investigating Farm Fragmentation as a Risk Factor for Bovine Tuberculosis in Cattle Herds: A Matched Case-Control Study from Northern Ireland. Pathogens 2022; 11:pathogens11030299. [PMID: 35335623 PMCID: PMC8954255 DOI: 10.3390/pathogens11030299] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 02/16/2022] [Accepted: 02/21/2022] [Indexed: 02/04/2023] Open
Abstract
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 discontinuous land parcels, and these highly fragmented farms are thought to facilitate localised spread. We conducted a matched case control study to quantify the risks of bovine tuberculosis breakdown with farm area, farm fragmentation, fragment dispersal, and contact with neighbouring herds. Whilst our results show small but significant increases in breakdown risk associated with each factor, these relationships were strongly confounded with the number of contiguous neighbours with bovine tuberculosis. Our key finding was that every infected neighbour led to an increase in the odds of breakdown by 40% to 50%, and that highly fragmented farms were almost twice as likely to have a bTB positive neighbour compared to nonfragmented farms. Our results suggest that after controlling for herd size, herd type, spatial and temporal factors, farm fragmentation increasingly exposes herds to infection originating from first-order spatial neighbours. Given Northern Ireland’s particularly fragmented landscape, and reliance on short-term leases, our data support the hypothesis that between-herd contiguous spread is a particularly important component of the region’s bovine tuberculosis disease system.
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Affiliation(s)
- Georgina Milne
- Agri-Food and Biosciences Institute (AFBI), Belfast BT4 3SD, UK;
- Correspondence:
| | - Jordon Graham
- Agri-Food and Biosciences Institute (AFBI), Belfast BT4 3SD, UK;
| | - John McGrath
- Department of Agriculture, Environment and Rural Affairs (Area Based Scheme), Londonderry BT48 6AT, UK;
| | - Raymond Kirke
- Department of Agriculture, Environment and Rural Affairs (Veterinary Service Animal Health), Limavady BT49 9HP, UK;
| | - Wilma McMaster
- Department of Agriculture, Environment and Rural Affairs (Land Parcel Identification System), Ballymena BT43 6HY, UK;
| | - Andrew William Byrne
- One-Health Unit, Department of Agriculture, Food and the Marine, D02 WK12 Dublin, Ireland;
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Barroso P, Breslin P, McGrath G, Madden JM, Tratalos JA, More SJ, Ryan E, Byrne AW, Barrett D. Is there an association between road building and bovine tuberculosis herd risk? A three time-point study in Ireland, 2011-2019. Prev Vet Med 2021; 198:105542. [PMID: 34798305 DOI: 10.1016/j.prevetmed.2021.105542] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 11/09/2021] [Accepted: 11/11/2021] [Indexed: 10/19/2022]
Abstract
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 with an increased risk of bTB in associated cattle herds. For this study, we considered three observation periods: pre-construction (2011-2014), construction (2015-2017) and post-construction (2018-2019). We selected 1543 herds situated, based on proximity, between >50 m and <5 km of the roadworks, and extracted information about their herd-size, herd-type, inward animal movements, bTB history, and distance to the roadworks. Generalized linear mixed models were performed, whose outcome were whether a herd experienced a bTB breakdown with ≥1 or ≥3 standard reactor/s, respectively. Herds located at a distance of >3 km from the roadworks were found to be at reduced risk of a bTB breakdown over the construction period compared with those situated within 1 km of the roadworks for ≥1 reactor/s (>3 km and construction vs. <1 km: OR: 0.595, 95 % Confidence Interval (CI): 0.354-0.999) or ≥3 reactors (>3 km and construction vs. <1 km: OR: 0.431, 95 % CI: 0.174-1.067). Other previously reported risk factors such as inward movements, herd-size and herd-type were also associated with bTB risk in the final models (≥1 reactor/s and ≥3 reactors). These findings appear to be consistent with bTB breakdowns being a consequence as opposed to coincident to road construction, given the temporal and spatial consistency of the evidence. The potential for badger social group disturbance leading to the spatial spread of infection to cattle herds, as previously described in the United Kingdom, could be a hypothetical mechanism to explain these findings. However, our findings are not consistent with previous Irish studies, including recent work from another road construction project, albeit running alongside and cross over an existing road rather than construction of a new road as in this case, or experiences from national targeted badger removal. Further research is warranted to verify this pattern occurs elsewhere, and the underlying biological mechanism. Until further data are available, we recommend that badgers are vaccinated, as a precautionary measure, in advance of the commencement of major roadworks.
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Affiliation(s)
- Patricia Barroso
- Grupo SaBio, Instituto de Investigación en Recursos Cinegéticos (UCLM-CSIC), Ciudad Real, Spain.
| | - Philip Breslin
- Ruminant Animal Health Division, Department of Agriculture, Food and the Marine (DAFM), Backweston, Co. Dublin, Ireland
| | - Guy McGrath
- Centre for Veterinary Epidemiology and Risk Analysis (CVERA), School of Veterinary Medicine, University College Dublin, Belfield, Dublin D04 W6F6, Ireland
| | - Jamie M Madden
- Centre for Veterinary Epidemiology and Risk Analysis (CVERA), School of Veterinary Medicine, University College Dublin, Belfield, Dublin D04 W6F6, Ireland
| | - Jamie A Tratalos
- Centre for Veterinary Epidemiology and Risk Analysis (CVERA), School of Veterinary Medicine, University College Dublin, Belfield, Dublin D04 W6F6, Ireland
| | - Simon J More
- Centre for Veterinary Epidemiology and Risk Analysis (CVERA), School of Veterinary Medicine, University College Dublin, Belfield, Dublin D04 W6F6, Ireland
| | - Eoin Ryan
- Ruminant Animal Health Division, Department of Agriculture, Food and the Marine (DAFM), Backweston, Co. Dublin, Ireland
| | - Andrew W Byrne
- One Health Scientific Support Unit, National Disease Control Centre (NDCC), Department of Agriculture, Food and the Marine (DAFM), Agriculture House, Dublin 2, Ireland
| | - Damien Barrett
- One Health Scientific Support Unit, National Disease Control Centre (NDCC), Department of Agriculture, Food and the Marine (DAFM), Agriculture House, Dublin 2, Ireland
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7
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Brock J, Lange M, Tratalos JA, More SJ, Graham DA, Guelbenzu-Gonzalo M, Thulke HH. Combining expert knowledge and machine-learning to classify herd types in livestock systems. Sci Rep 2021; 11:2989. [PMID: 33542295 PMCID: PMC7862359 DOI: 10.1038/s41598-021-82373-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 01/13/2021] [Indexed: 11/20/2022] Open
Abstract
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.
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Affiliation(s)
- Jonas Brock
- Department of Ecological Modelling, PG Ecological Epidemiology, Helmholtz Centre for Environmental Research GmbH-UFZ, Leipzig, Germany. .,Animal Health Ireland, Carrick-on-Shannon, Co., Leitrim, Ireland.
| | - Martin Lange
- Department of Ecological Modelling, PG Ecological Epidemiology, Helmholtz Centre for Environmental Research GmbH-UFZ, Leipzig, Germany
| | - Jamie A Tratalos
- Centre for Veterinary Epidemiology and Risk Analysis, UCD School of Veterinary Medicine, University College Dublin, Dublin, D04 W6F6, Ireland
| | - Simon J More
- Centre for Veterinary Epidemiology and Risk Analysis, UCD School of Veterinary Medicine, University College Dublin, Dublin, D04 W6F6, Ireland
| | - David A Graham
- Animal Health Ireland, Carrick-on-Shannon, Co., Leitrim, Ireland
| | | | - Hans-Hermann Thulke
- Department of Ecological Modelling, PG Ecological Epidemiology, Helmholtz Centre for Environmental Research GmbH-UFZ, Leipzig, Germany
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Djafar ZR, Benazi N, Bounab S, Sayhi M, Diouani MF, Benia F. Distribution of seroprevalence and risk factors for bovine tuberculosis in east Algeria. Prev Vet Med 2020; 183:105127. [PMID: 32905887 DOI: 10.1016/j.prevetmed.2020.105127] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 08/19/2020] [Accepted: 08/20/2020] [Indexed: 11/15/2022]
Abstract
Despite the difficulties and the absence of credible scientific information concerning bovine tuberculosis in Algeria, our cross-sectional and inferential study, which is estimated to be a first in Algeria, affected three major semi-intensive regions in East of Algeria, by analyzing 21 holdings which grouped 516 cattle in an intensive and semi-intensive breeding character over a period of 12 months, in order to estimate the seroprevalence and the risk factors those influence the emergence of the disease in these regions. A serological test (ELISA) was carried out on all collected sera, after a stratified two-level sampling. A generalized linear mixed model was used to identify risk factors associated with animal-level positivity. A multivariate descriptive analysis (MCA) was used to identify farm clusters associated with bTB seroprevalence. The results obtained allow us to classify Algeria on the epidemiological level in the field of bovine tuberculosis, in an intermediate situation with a seroprevalence rate of 3.49 % (95 % CI : 1,91, 507); between industrialized countries where the seroprevalence is mostly very low below 0,1% and developing countries with very high seroprevalence such as African-Asian countries. This intermediate epidemiological position is influenced by certain risk factors that are integrated into the three mechanisms commonly known by the scientific community: "contamination by the introduction of an animal"; "neighborhood contamination"; "recurrence". But what characterizes this study is the obtaining of a "Animals purchased from a country listed as not OTF" factor that has returned as a highly protective factor and contributed to the decrease in this seroprevalence, and put Algeria in an intermediate epidemiological situation according to our study, and this is due to a purchase channeled by the state which is exclusive of the countries certified OTF by the OIE.
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Affiliation(s)
- Zehaira Romeissa Djafar
- Laboratory of Improvement and Development of Plant and Animal Production (ADPVA), 19000, Sétif, Algeria; University of Sétif1, Faculty of Sciences, 19000, Sétif, Algeria
| | - Nabil Benazi
- Institut PASTEUR Algérie, Annexe, M'sila, 28000, Algeria.
| | - Sabrina Bounab
- Laboratory of Physics and Chemistry of Materials, Faculty of Sciences, University of M'sila, 28000, M'sila, Algeria
| | - Maher Sayhi
- Laboratory of Epidemiology and Veterinary Microbiology (LEMV), Pasteur Institute of Tunis, LR11IPT03, Tunis-Belvédère 1002, Tunisia; Faculty of Sciences of Tunis, University of Tunis El Manar, Tunisia; Université Tunis El Manar, Tunis, 1068, Tunisia
| | - Mohamed Fethi Diouani
- Laboratory of Epidemiology and Veterinary Microbiology (LEMV), Pasteur Institute of Tunis, LR11IPT03, Tunis-Belvédère 1002, Tunisia; Université Tunis El Manar, Tunis, 1068, Tunisia
| | - Farida Benia
- Laboratory of Improvement and Development of Plant and Animal Production (ADPVA), 19000, Sétif, Algeria; University of Sétif1, Faculty of Sciences, 19000, Sétif, Algeria
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Fielding HR, McKinley TJ, Delahay RJ, Silk MJ, McDonald RA. Effects of trading networks on the risk of bovine tuberculosis incidents on cattle farms in Great Britain. ROYAL SOCIETY OPEN SCIENCE 2020; 7:191806. [PMID: 32431877 PMCID: PMC7211880 DOI: 10.1098/rsos.191806] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 03/23/2020] [Indexed: 06/11/2023]
Abstract
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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Affiliation(s)
- Helen R. Fielding
- Environment and Sustainability Institute, Mathematics and Physical Sciences, University of Exeter, Penryn Campus, Penryn TR10 9FE, UK
- The Royal (Dick) School of Veterinary Studies and The Roslin Institute, University of Edinburgh, Easter Bush Campus, Midlothian EH25 9RG, UK
| | - Trevelyan J. McKinley
- College of Engineering, Mathematics and Physical Sciences, University of Exeter, Penryn Campus, Penryn TR10 9FE, UK
| | - Richard J. Delahay
- Animal and Plant Health Agency, Woodchester Park, Nympsfield, Stonehouse GL10 3UJ, UK
| | - Matthew J. Silk
- Environment and Sustainability Institute, Mathematics and Physical Sciences, University of Exeter, Penryn Campus, Penryn TR10 9FE, UK
| | - Robbie A. McDonald
- Environment and Sustainability Institute, Mathematics and Physical Sciences, University of Exeter, Penryn Campus, Penryn TR10 9FE, UK
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Romero MP, Chang YM, Brunton LA, Parry J, Prosser A, Upton P, Rees E, Tearne O, Arnold M, Stevens K, Drewe JA. Decision tree machine learning applied to bovine tuberculosis risk factors to aid disease control decision making. Prev Vet Med 2019; 175:104860. [PMID: 31812850 DOI: 10.1016/j.prevetmed.2019.104860] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 11/26/2019] [Accepted: 11/27/2019] [Indexed: 12/19/2022]
Abstract
Identifying and understanding the risk factors for endemic bovine tuberculosis (TB) in cattle herds is critical for the control of this disease. Exploratory machine learning techniques can uncover complex non-linear relationships and interactions within disease causation webs, and enhance our knowledge of TB risk factors and how they are interrelated. Classification tree analysis was used to reveal associations between predictors of TB in England and each of the three surveillance risk areas (High Risk, Edge, and Low Risk) in 2016, identifying the highest risk herds. The main classifying predictor for farms in England overall related to the TB prevalence in the 100 nearest cattle herds. In the High Risk and Edge areas it was the number of slaughterhouse destinations and in the Low Risk area it was the number of cattle tested in surveillance tests. How long ago the last confirmed incident was resolved was the most frequent classifier in trees; if within two years, leading to the highest risk group of herds in the High Risk and Low Risk areas. At least two different slaughterhouse destinations led to the highest risk group of herds in England, whereas in the Edge area it was a combination of no contiguous low-risk neighbours (i.e. in a 1 km radius) and a minimum proportion of 6-23 month-old cattle in November. A threshold value of prevalence in 100 nearest neighbours increased the risk in all areas, although the value was specific to each area. Having low-risk contiguous neighbours reduced the risk in the Edge and High Risk areas, whereas high-risk ones increased the risk in England overall and in the Edge area specifically. The best classification tree models informed multivariable binomial logistic regression models in each area, adding statistical inference outputs. These two approaches showed similar predictive performance although there were some disparities regarding what constituted high-risk predictors. Decision tree machine learning approaches can identify risk factors from webs of causation: information which may then be used to inform decision making for disease control purposes.
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Affiliation(s)
- M Pilar Romero
- Animal and Plant Health Agency, Woodham Lane, Addlestone, Surrey, KT15 3NB, United Kingdom; Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire, AL9 7TA, United Kingdom.
| | - Yu-Mei Chang
- Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire, AL9 7TA, United Kingdom
| | - Lucy A Brunton
- Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire, AL9 7TA, United Kingdom
| | - Jessica Parry
- Animal and Plant Health Agency, Woodham Lane, Addlestone, Surrey, KT15 3NB, United Kingdom
| | - Alison Prosser
- Animal and Plant Health Agency, Woodham Lane, Addlestone, Surrey, KT15 3NB, United Kingdom
| | - Paul Upton
- Animal and Plant Health Agency, Woodham Lane, Addlestone, Surrey, KT15 3NB, United Kingdom
| | - Eleanor Rees
- Animal and Plant Health Agency, Woodham Lane, Addlestone, Surrey, KT15 3NB, United Kingdom
| | - Oliver Tearne
- Animal and Plant Health Agency, Woodham Lane, Addlestone, Surrey, KT15 3NB, United Kingdom
| | - Mark Arnold
- Animal and Plant Health Agency, Woodham Lane, Addlestone, Surrey, KT15 3NB, United Kingdom
| | - Kim Stevens
- Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire, AL9 7TA, United Kingdom
| | - Julian A Drewe
- Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire, AL9 7TA, United Kingdom
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11
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Prevalence of bovine tuberculosis and its associated risk factors in the emerging dairy belts of regional cities in Ethiopia. Prev Vet Med 2019; 168:81-89. [PMID: 31097127 PMCID: PMC10364076 DOI: 10.1016/j.prevetmed.2019.04.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 03/22/2019] [Accepted: 04/22/2019] [Indexed: 11/23/2022]
Abstract
Bovine tuberculosis (BTB) has become an economically important disease in dairy herds found in and around Addis Ababa City and is emerging in regional cities like Gondar, Hawassa and Mekelle because of the establishment of dairy farms in the milk sheds of these cities. A cross-sectional study to estimate the prevalence of BTB and identify associated risk factors was conducted between February 2016 and March 2017. A total of 174 herds comprising of 2,754 dairy cattle in the cities of Gondar, Hawassa and Mekelle were tested using the Single Intradermal Comparative Cervical Tuberculin (SICCT) test. Data on herd structure, animal origin, body condition, housing condition, farm hygiene, management and biosecurity practices were collected using a pre-tested structured questionnaire. Generalized Linear Models (GLM) and Generalized Linear Mixed Models (GLMM) were used to analyze the herd and animal level risk factors, respectively. The herd prevalence was 22.4% (95% CI: 17-29%) while the animal prevalence was 5.2% (95% CI: 4-6%) at the cut-off >4 mm. The herd prevalence rose to 65.5% (95% CI: 58-72%) and the animal prevalence rose to 9% (95% CI: 8-10%) when the severe interpretation of >2 mm cut-off was applied. The mean within-herd prevalence in positive farms at the cut-off >4 mm was 22.7% (95% CI: 15-31%). At the herd level, the analysis showed that herd size, farm hygiene, feeding condition and biosecurity were significantly associated with BTB status, while new cattle introductions showed only borderline significance and that age of farm, housing condition, farmers' educational status and animal health care practice were not significant. At the animal level, the results showed that age and animal origin were identified as significant predictors for BTB positivity but sex and body condition score were not related to BTB status. Descriptive analysis revealed that herds having 'BTB history' showed slightly higher likelihood of being BTB positive compared to farms having no previous BTB exposure. In conclusion, this study showed relatively lower average prevalence in the emerging dairy regions as compared to the prevalence observed in and around Addis Ababa City, warranting for implementation of control program at this stage to reduce or possibly stop further transmission of BTB.
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12
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Li M, Yu W, Tian W, Ge Y, Liu Y, Ding T, Zhang L. System dynamics modeling of public health services provided by China CDC to control infectious and endemic diseases in China. Infect Drug Resist 2019; 12:613-625. [PMID: 30936725 PMCID: PMC6422414 DOI: 10.2147/idr.s185177] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Infectious and endemic diseases are a serious public health concern worldwide, and their prevention and treatment are globally controversial. This study aimed to establish an system dynamics (SD) model to analyze the factors influencing public health services provided by the Chinese Centers for Disease Control and Prevention (China CDC) to implement infectious and endemic disease control in China, by establishing more effective interventions to provide public health services and thus achieving the goal of controlling infectious and endemic diseases. MATERIALS AND METHODS An SD model was constructed using the Vensim DSS program. Intervention experiments were performed using the SD model, which reflected the influences on disease control by adjusting the governmental investment and compensation level for public health products. RESULTS The experimental results showed that increasing the governmental investment in China CDC and compensation level for public health products will significantly increase the public health product rate provided by China CDC. DISCUSSION Problems with infectious and endemic disease prevention and treatment are the result of the system's incomplete functioning and limited health resources. To address the current problems and improve the system, the government should increase its investment in the public health service system and improve the compensation system to ensure smooth implementation of infectious and endemic disease prevention and treatment and, ultimately, improve public health in China.
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Affiliation(s)
- Meina Li
- Department of Military Health Service Management, College of Military Health Service Management, Second Military Medical University, Shanghai, China,
| | - Wenya Yu
- Department of Military Health Service Management, College of Military Health Service Management, Second Military Medical University, Shanghai, China,
| | - Wei Tian
- Medical Care Department, Dalian Rehabilitation Center of PLA, Dalian, China
| | - Yang Ge
- School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yuan Liu
- Department of Military Health Service Management, College of Military Health Service Management, Second Military Medical University, Shanghai, China,
| | - Tao Ding
- Department of Military Health Service Management, College of Military Health Service Management, Second Military Medical University, Shanghai, China,
| | - Lulu Zhang
- Department of Military Health Service Management, College of Military Health Service Management, Second Military Medical University, Shanghai, China,
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13
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Byrne AW, McBride S, Graham J, Lahuerta-Marin A, McNair J, Skuce RA, McDowell SW. Liver fluke (Fasciola hepatica) co-infection with bovine tuberculosis (bTB) in cattle: A retrospective animal-level assessment of bTB risk in dairy and beef cattle. Transbound Emerg Dis 2018; 66:785-796. [PMID: 30484969 DOI: 10.1111/tbed.13083] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 10/08/2018] [Accepted: 11/07/2018] [Indexed: 11/30/2022]
Abstract
Bovine tuberculosis (bTB), caused by Mycobacterium bovis, remains a persistent problem for cattle industries in endemic countries. The frequency, quality, and performance of tests, and the presence of wildlife reservoirs, have been identified as impediments to eradication. Recently, exposure to helminth infection (Fasciola hepatica) has been associated negatively with the disclosure of bTB. Here, for the first time, we assess impact of concurrent infections of Fasciola hepatica and the disclosure of bTB at the animal-level using large surveillance datasets. We utilized a dataset of 138,566 animal records from an abattoir from Northern Ireland (2011-2013). The presence of F. hepatica infection was assessed from macroscopic tissue inspection at abattoir. Multivariable models were developed to assess co-infection associations with bTB status based on: Single Intradermal Comparative Tuberculin Test (SICTT), lesion, bacteriological confirmation, including either all animals, or only skin-test negative animals (lesions at routine slaughter; LRS; confirmed nonreactors at routine slaughter; cNRs) or positive (reactors) animals alone, respectively. The relationship between skin tuberculin reaction sizes and fluke status was also explored for a subset of animals with field recordings (n = 24,680). Controlling for known risk factors (e.g., climatic, herd, and individual level characteristics), we did not find significant associations between the SICTT (standard or severe interpretation), lesion, nor confirmation status of animals and their liver fluke status. The only exception was a negative association between liver fluke positivity, and LRS or cNRs, respectively; though effect-sizes were small (e.g., LRS Odds-Ratio: 0.87; 95% CI: 0.76-1.00). There was limited evidence of a relationship between tuberculin reaction sizes during SICTT testing and liver fluke infection status. These data do not support the contention that the detection of bTB using skin-tests or reactor postmortem follow-up may be compromised by co-infection at a population level, but the relationship with lesion formation (pathogenesis) may indicate an impact for postmortem surveillance.
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Affiliation(s)
- Andrew W Byrne
- AFBI Stormont, Agri-Food and Biosciences Institute (AFBI), Belfast, UK.,School of Biological Sciences, Queen's University Belfast, Belfast, UK
| | - Stewart McBride
- AFBI Stormont, Agri-Food and Biosciences Institute (AFBI), Belfast, UK
| | - Jordon Graham
- AFBI Stormont, Agri-Food and Biosciences Institute (AFBI), Belfast, UK
| | | | - Jim McNair
- AFBI Stormont, Agri-Food and Biosciences Institute (AFBI), Belfast, UK
| | - Robin A Skuce
- AFBI Stormont, Agri-Food and Biosciences Institute (AFBI), Belfast, UK
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14
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Brunton LA, Prosser A, Pfeiffer DU, Downs SH. Exploring the Fate of Cattle Herds With Inconclusive Reactors to the Tuberculin Skin Test. Front Vet Sci 2018; 5:228. [PMID: 30324110 PMCID: PMC6173137 DOI: 10.3389/fvets.2018.00228] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 09/04/2018] [Indexed: 01/30/2023] Open
Abstract
Bovine tuberculosis (TB) is an important animal health issue in many parts of the world. In England and Wales, the primary test to detect infected animals is the single intradermal comparative cervical tuberculin test, which compares immunological responses to bovine and avian tuberculins. Inconclusive test reactors (IRs) are animals that demonstrate a positive reaction to the bovine tuberculin only marginally greater than the avian reaction, so are not classified as reactors and immediately removed. In the absence of reactors in the herd, IRs are isolated, placed under movement restrictions and re-tested after 60 days. Other animals in these herds at the time of the IR result are not usually subject to movement restrictions. This could affect efforts to control TB if undetected infected cattle move out of those herds before the next TB test. To improve our understanding of the importance of IRs, this study aimed to assess whether median survival time and the hazard of a subsequent TB incident differs in herds with only IRs detected compared with negative-testing herds. Survival analysis and extended Cox regression were used, with herds entering the study on the date of the first whole herd test in 2012. An additional analysis was performed using an alternative entry date to try to remove the impact of IR retesting and is presented in the Supplementary Material. Survival analysis showed that the median survival time among IR only herds was half that observed for clear herds (2.1 years and 4.2 years respectively; p < 0.001). Extended Cox regression analysis showed that IR-only herds had 2.7 times the hazard of a subsequent incident compared with negative-testing herds in year one (hazard ratio: 2.69; 95% CI: 2.54, 2.84; p < 0.001), and that this difference in the hazard reduced by 63% per year. After 2.7 years the difference had disappeared. The supplementary analysis supported these findings showing that IR only herds still had a greater hazard of a subsequent incident after the IR re-test, but that the effect was reduced. This emphasizes the importance of careful decision making around the management of IR animals and indicates that re-testing alone may not be sufficient to reduce the risk posed by IR only herds in England and Wales.
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Affiliation(s)
- Lucy A. Brunton
- Veterinary Epidemiology, Economics and Public Health Group, Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, London, United Kingdom
| | - Alison Prosser
- Data Systems Group, Department of Epidemiological Sciences, Animal and Plant Health Agency, Weybridge, United Kingdom
| | - Dirk U. Pfeiffer
- Veterinary Epidemiology, Economics and Public Health Group, Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, London, United Kingdom
- College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon Tong, China
| | - Sara H. Downs
- Epidemiology Group, Department of Epidemiological Sciences, Animal and Plant Health Agency, Weybridge, United Kingdom
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15
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Factors Affecting Herd Status for Bovine Tuberculosis in Dairy Cattle in Northern Thailand. Vet Med Int 2017; 2017:2964389. [PMID: 28553557 PMCID: PMC5434264 DOI: 10.1155/2017/2964389] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 02/25/2017] [Accepted: 03/22/2017] [Indexed: 11/17/2022] Open
Abstract
The objective of this case-control study was to identify farm-level risk factors associated with bovine tuberculosis (bTB) in dairy cows in northern Thailand. Spatial analysis was performed to identify geographical clustering of case-farms located in Chiang Mai and Chiang Rai provinces in northern Thailand. To identify management factors affecting bTB status, a matched case-control study was conducted with 20 case-farms and 38 control-farms. Case-farms were dairy farms with at least single intradermal tuberculin test- (SIT-) reactor(s) in the farms during 2011 to 2015. Control-farms were dairy farms with no SIT-reactors in the same period and located within 5 km from case-farms. Questionnaires were administered for data collection with questions based on epidemiological plausibility and characteristics of the local livestock industry. Data were analyzed using multiple logistic regressions. A significant geographic cluster was identified only in Chiang Mai province (p < 0.05). The risk factor associated with presence of SIT-reactors in dairy herds located in this region was purchasing dairy cows from dealers (OR = 5.85, 95% CI = 1.66-20.58, and p = 0.006). From this study, it was concluded that geographic clustering was identified for dairy farms with SIT-reactors in these provinces, and the cattle movements through cattle dealers increased the risks for SIT-reactor farm status.
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16
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Raphaka K, Matika O, Sánchez-Molano E, Mrode R, Coffey MP, Riggio V, Glass EJ, Woolliams JA, Bishop SC, Banos G. Genomic regions underlying susceptibility to bovine tuberculosis in Holstein-Friesian cattle. BMC Genet 2017; 18:27. [PMID: 28335717 PMCID: PMC5364629 DOI: 10.1186/s12863-017-0493-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2016] [Accepted: 03/16/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The significant social and economic loss as a result of bovine tuberculosis (bTB) presents a continuous challenge to cattle industries in the UK and worldwide. However, host genetic variation in cattle susceptibility to bTB provides an opportunity to select for resistant animals and further understand the genetic mechanisms underlying disease dynamics. METHODS The present study identified genomic regions associated with susceptibility to bTB using genome-wide association (GWA), regional heritability mapping (RHM) and chromosome association approaches. Phenotypes comprised de-regressed estimated breeding values of 804 Holstein-Friesian sires and pertained to three bTB indicator traits: i) positive reactors to the skin test with positive post-mortem examination results (phenotype 1); ii) positive reactors to the skin test regardless of post-mortem examination results (phenotype 2) and iii) as in (ii) plus non-reactors and inconclusive reactors to the skin tests with positive post-mortem examination results (phenotype 3). Genotypes based on the 50 K SNP DNA array were available and a total of 34,874 SNPs remained per animal after quality control. RESULTS The estimated polygenic heritability for susceptibility to bTB was 0.26, 0.37 and 0.34 for phenotypes 1, 2 and 3, respectively. GWA analysis identified a putative SNP on Bos taurus autosomes (BTA) 2 associated with phenotype 1, and another on BTA 23 associated with phenotype 2. Genomic regions encompassing these SNPs were found to harbour potentially relevant annotated genes. RHM confirmed the effect of these genomic regions and identified new regions on BTA 18 for phenotype 1 and BTA 3 for phenotypes 2 and 3. Heritabilities of the genomic regions ranged between 0.05 and 0.08 across the three phenotypes. Chromosome association analysis indicated a major role of BTA 23 on susceptibility to bTB. CONCLUSION Genomic regions and candidate genes identified in the present study provide an opportunity to further understand pathways critical to cattle susceptibility to bTB and enhance genetic improvement programmes aiming at controlling and eradicating the disease.
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Affiliation(s)
- Kethusegile Raphaka
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, Scotland, UK.
| | - Oswald Matika
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, Scotland, UK
| | - Enrique Sánchez-Molano
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, Scotland, UK
| | - Raphael Mrode
- Scotland's Rural College, The Roslin Institute Building, Easter Bush, Midlothian, EH25 9RG, Edinburgh, UK
| | - Mike Peter Coffey
- Scotland's Rural College, The Roslin Institute Building, Easter Bush, Midlothian, EH25 9RG, Edinburgh, UK
| | - Valentina Riggio
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, Scotland, UK
| | - Elizabeth Janet Glass
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, Scotland, UK
| | - John Arthur Woolliams
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, Scotland, UK
| | - Stephen Christopher Bishop
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, Scotland, UK
| | - Georgios Banos
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, Scotland, UK.,Scotland's Rural College, The Roslin Institute Building, Easter Bush, Midlothian, EH25 9RG, Edinburgh, UK
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17
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Picasso C, Alvarez J, VanderWaal KL, Fernandez F, Gil A, Wells SJ, Perez A. Epidemiological investigation of bovine tuberculosis outbreaks in Uruguay (2011-2013). Prev Vet Med 2017; 138:156-161. [PMID: 28237231 DOI: 10.1016/j.prevetmed.2017.01.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 11/28/2016] [Accepted: 01/16/2017] [Indexed: 11/18/2022]
Abstract
Bovine tuberculosis (bTB) is a chronic disease of cattle caused by infection with the Mycobacterium bovis. While bTB prevalence in Uruguay has been low (<11 outbreaks/year) for the past 50 years as a consequence of a national control program, annual incidence increased in 2011 through 2013-15, 26 and 16 infected herds each year, raising concerns from livestock stakeholders and the government. The goal of this study was to assess the spatial dynamics of bTB in Uruguay from 2011 to 2013 and the association between bTB and potential demographic and movement risk factors at the herd level using data provided by the Uruguayan Ministry of Livestock, Agriculture, and Fisheries. Clustering of incident outbreaks was assessed using the Cuzick-Edwards' test and the Bernoulli model of the spatial scan statistic, and a conditional multivariable logistic regression model was used to assess risk factors associated with bTB in a subset of Uruguayan dairy farms. Significant (P<0.05) global clustering was detected in 2012, while high-risk local clusters were detected in southwestern (2011, 2012, 2013), northwestern (2012), and southeastern (2012) Uruguay. Increased risk of bTB in different regions of Uruguay suggests a potential role of animal movements in disease dissemination. Larger herds, higher numbers of animals purchased, and incoming steers to the farm were associated with increased odds of breaking with bTB, in agreement with previous studies but also suggesting other additional sources of risk. These results will contribute to enhanced effectiveness of bTB control programs in Uruguay with the ultimate objective of preventing or mitigating the impact of the disease in the human and animal populations of the country.
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Affiliation(s)
- Catalina Picasso
- Department of Veterinary Population Medicine, University of Minnesota, 1365 Gortner Avenue, St. Paul, MN, 55108, United States; Animal Health Bureau, Ministry of Livestock, Agriculture, and Fisheries, 1476 Constituyente, Montevideo, 11200, Uruguay.
| | - Julio Alvarez
- Department of Veterinary Population Medicine, University of Minnesota, 1365 Gortner Avenue, St. Paul, MN, 55108, United States.
| | - Kimberly L VanderWaal
- Department of Veterinary Population Medicine, University of Minnesota, 1365 Gortner Avenue, St. Paul, MN, 55108, United States.
| | - Federico Fernandez
- Animal Health Bureau, Ministry of Livestock, Agriculture, and Fisheries, 1476 Constituyente, Montevideo, 11200, Uruguay.
| | - Andres Gil
- Facultad de Veterinaria, Universidad de la Republica,1550 Alberto Lasplaces, Montevideo, 11100, Uruguay.
| | - Scott J Wells
- Department of Veterinary Population Medicine, University of Minnesota, 1365 Gortner Avenue, St. Paul, MN, 55108, United States.
| | - Andres Perez
- Department of Veterinary Population Medicine, University of Minnesota, 1365 Gortner Avenue, St. Paul, MN, 55108, United States.
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18
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Winkler B, Mathews F. Environmental risk factors associated with bovine tuberculosis among cattle in high-risk areas. Biol Lett 2016; 11:rsbl.2015.0536. [PMID: 26559511 DOI: 10.1098/rsbl.2015.0536] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Our research shows that environmental features are important predictors of bovine tuberculosis (bTB) in British cattle herds in high-prevalence regions. Data from 503 case and 808 control farms included in the randomized badger culling trial (RBCT) were analysed. bTB risk increased in larger herds and on farms with greater areas of maize, deciduous woodland and marsh, whereas a higher percentage of boundaries composed of hedgerows decreased the risk. The model was tested on another case-control study outside RBCT areas, and here it had a much smaller predictive power. This suggests that different infection dynamics operate outside high-risk areas, although it is possible that unknown confounding factors may also have played a role.
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Affiliation(s)
- B Winkler
- Hatherly Laboratories, Biosciences, College of Life and Environmental Sciences, University of Exeter, Prince of Wales Road, Exeter EX4 4PS, UK
| | - F Mathews
- Hatherly Laboratories, Biosciences, College of Life and Environmental Sciences, University of Exeter, Prince of Wales Road, Exeter EX4 4PS, UK
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19
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Marsot M, Béral M, Scoizec A, Mathevon Y, Durand B, Courcoul A. Herd-level risk factors for bovine tuberculosis in French cattle herds. Prev Vet Med 2016; 131:31-40. [DOI: 10.1016/j.prevetmed.2016.07.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 07/05/2016] [Accepted: 07/07/2016] [Indexed: 11/25/2022]
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20
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A review of risk factors for bovine tuberculosis infection in cattle in the UK and Ireland. Epidemiol Infect 2016; 144:2899-2926. [DOI: 10.1017/s095026881600131x] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
SUMMARYBovine tuberculosis (bTB) is an important disease of cattle caused by infection withMycobacterium bovis, a pathogen that may be extremely difficult to eradicate in the presence of a true wildlife reservoir. Our objective was to identify and review relevant literature and provide a succinct summary of current knowledge of risk factors for transmission of infection of cattle. Search strings were developed to identify publications from electronic databases to February 2015. Abstracts of 4255 papers identified were reviewed by three reviewers to determine whether the entire article was likely to contain relevant information. Risk factors could be broadly grouped as follows: animal (including nutrition and genetics), herd (including bTB and testing history), environment, wildlife and social factors. Many risk factors are inter-related and study designs often do not enable differentiation between cause and consequence of infection. Despite differences in study design and location, some risk factors are consistently identified, e.g. herd size, bTB history, presence of infected wildlife, whereas the evidence for others is less consistent and coherent, e.g. nutrition, local cattle movements. We have identified knowledge gaps where further research may result in an improved understanding of bTB transmission dynamics. The application of targeted, multifactorial disease control regimens that address a range of risk factors simultaneously is likely to be a key to effective, evidence-informed control strategies.
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Dejene SW, Heitkönig IMA, Prins HHT, Lemma FA, Mekonnen DA, Alemu ZE, Kelkay TZ, de Boer WF. Risk Factors for Bovine Tuberculosis (bTB) in Cattle in Ethiopia. PLoS One 2016; 11:e0159083. [PMID: 27404387 PMCID: PMC4942063 DOI: 10.1371/journal.pone.0159083] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 06/27/2016] [Indexed: 11/22/2022] Open
Abstract
Bovine tuberculosis (bTB) infection is generally correlated with individual cattle's age, sex, body condition, and with husbandry practices such as herd composition, cattle movement, herd size, production system and proximity to wildlife-including bTB maintenance hosts. We tested the correlation between those factors and the prevalence of bTB, which is endemic in Ethiopia's highland cattle, in the Afar Region and Awash National Park between November 2013 and April 2015. A total of 2550 cattle from 102 herds were tested for bTB presence using the comparative intradermal tuberculin test (CITT). Data on herd structure, herd movement, management and production system, livestock transfer, and contact with wildlife were collected using semi-structured interviews with cattle herders and herd owners. The individual overall prevalence of cattle bTB was 5.5%, with a herd prevalence of 46%. Generalized Linear Mixed Models with a random herd-effect were used to analyse risk factors of cattle reactors within each herd. The older the age of the cattle and the lower the body condition the higher the chance of a positive bTB test result, but sex, lactation status and reproductive status were not correlated with bTB status. At herd level, General Linear Models showed that pastoral production systems with transhumant herds had a higher bTB prevalence than sedentary herds. A model averaging analysis identified herd size, contact with wildlife, and the interaction of herd size and contact with wildlife as significant risk factors for bTB prevalence in cattle. A subsequent Structural Equation Model showed that the probability of contact with wildlife was influenced by herd size, through herd movement. Larger herds moved more and grazed in larger areas, hence the probability of grazing in an area with wildlife and contact with either infected cattle or infected wildlife hosts increased, enhancing the chances for bTB infection. Therefore, future bTB control strategies in cattle in pastoral areas should consider herd size and movement as important risk factors.
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Affiliation(s)
- Sintayehu W. Dejene
- Resource Ecology Group, Wageningen University, Wageningen, the Netherlands
- College of Agriculture and Environmental Sciences, Haramaya University, Dire Dawa, Ethiopia
| | | | | | - Fitsum A. Lemma
- College of Veterinary Medicine, Haramaya University, Dire Dawa, Ethiopia
| | - Daniel A. Mekonnen
- College of Veterinary Medicine, Haramaya University, Dire Dawa, Ethiopia
| | - Zelalem E. Alemu
- College of Agriculture and Environmental Sciences, Haramaya University, Dire Dawa, Ethiopia
| | - Tessema Z. Kelkay
- College of Agriculture and Environmental Sciences, Haramaya University, Dire Dawa, Ethiopia
| | - Willem F. de Boer
- Resource Ecology Group, Wageningen University, Wageningen, the Netherlands
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22
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Broughan J, Maye D, Carmody P, Brunton L, Ashton A, Wint W, Alexander N, Naylor R, Ward K, Goodchild A, Hinchliffe S, Eglin R, Upton P, Nicholson R, Enticott G. Farm characteristics and farmer perceptions associated with bovine tuberculosis incidents in areas of emerging endemic spread. Prev Vet Med 2016; 129:88-98. [DOI: 10.1016/j.prevetmed.2016.05.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 05/10/2016] [Accepted: 05/13/2016] [Indexed: 10/21/2022]
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23
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Ghebremariam MK, Rutten VPMG, Vernooij JCM, Uqbazghi K, Tesfaalem T, Butsuamlak T, Idris AM, Nielen M, Michel AL. Prevalence and risk factors of bovine tuberculosis in dairy cattle in Eritrea. BMC Vet Res 2016; 12:80. [PMID: 27225267 PMCID: PMC4881182 DOI: 10.1186/s12917-016-0705-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 05/22/2016] [Indexed: 11/20/2022] Open
Abstract
Background The prevalence of bovine tuberculosis (BTB) in dairy cattle in the three major milk producing regions of Eritrea was assessed by subjecting 15,354 dairy cattle, 50 % of Eritrea’s dairy cattle population, to the single intradermal comparative tuberculin test (SICTT). Skin test results were interpreted according to guidelines of the World Organization for Animal Health (OIE) with >4 mm as cutoff in skin thickness increase. In addition, we studied the relation between ‘physiological’ variables related to pregnancy and lactation, and the variable ‘region’ on the probability to be skin test positive. Results The BTB prevalences at animal and herd levels were: 21.5 % and 40.9 % in Maekel, 7.3 % and 10 % in Debub, and 0.2 % and 1.6 % in the Anseba region, respectively. Overall, in the regions included, prevalence was 11.3 % (confidence interval (CI) 95 % CI, 11.29 – 11.31 %) and 17.3 % (95 % CI, 17.27–17.33 %), at animal and herd level, respectively. Considering positive herds only, the animal BTB prevalence was 36.8 %, 30.1 %, and 1.8 %, in Maekel, Debub and Anseba, respectively, and the overall animal prevalence within these herds was 32 %. In adult dairy cattle the probability of positive reactivity in the SICTT test was highest in pregnant animals as compared to the other categories. Conclusion This study reports persistent prevalence of BTB as defined by positive SICTT in the dairy sector of Eritrea, especially in the regions of Maekel and Debub that are located in the central highlands of the country. To our understanding this is the first report that has encompassed all the major dairy farms in Eritrea and it will be instrumental in advocating future BTB control programs in the dairy sector. Electronic supplementary material The online version of this article (doi:10.1186/s12917-016-0705-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Michael K Ghebremariam
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands. .,Department of Veterinary Sciences, Hamelmalo Agricultural College, Keren, Eritrea.
| | - V P M G Rutten
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.,Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
| | - J C M Vernooij
- Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - K Uqbazghi
- Veterinary Services, Ministry of Agriculture (MOA), Mendefera, Debub Region, Eritrea
| | - T Tesfaalem
- National Animal and Plant Health Laboratory, MOA, Asmara, Eritrea
| | - T Butsuamlak
- Veterinary Services, MOA, Keren, Anseba Region, Eritrea
| | - A M Idris
- Veterinary Services, MOA, Asmara, Maekel Region, Eritrea
| | - M Nielen
- Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - A L Michel
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
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O'Hagan MJH, Matthews DI, Laird C, McDowell SWJ. Herd-level risk factors for bovine tuberculosis and adoption of related biosecurity measures in Northern Ireland: A case-control study. Vet J 2016; 213:26-32. [PMID: 27240911 DOI: 10.1016/j.tvjl.2016.03.021] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 03/22/2016] [Accepted: 03/23/2016] [Indexed: 12/13/2022]
Abstract
Bovine tuberculosis (bTB) is a zoonotic disease which is endemic in Northern Ireland. As it has proven difficult to eradicate this disease, partly due to a wildlife reservoir being present in the European badger (Meles meles), a case-control study was conducted in a high incidence area in 2010-2011. The aim was to identify risk factors for bTB breakdown relating to cattle and badgers, and to assess the adoption of bTB related biosecurity measures on farms. Face-to-face questionnaires with farmers and surveys of badger setts and farm boundaries were conducted on 117 farms with a recent bTB breakdown (cases) and 75 farms without a recent breakdown (controls). On logistic regression at univariable and multivariable levels, significant risk factors associated with being a case herd included having an accessible badger sett within the farm boundaries in a field grazed in the last year (odds ratio, OR, 4.14; 95% confidence interval, CI, 1.79, 9.55), observation of live badgers (OR 4.14; 95% CI 1.79, 9.55), purchase of beef cattle (OR 4.60; 95% CI 1.61, 13.13), use of contractors to spread slurry (OR 2.83; 95% CI 1.24, 6.49), feeding meal on top of silage (OR 3.55; 95% CI 1.53, 8.23) and feeding magnesium supplement (OR = 3.77; 95% CI 1.39, 10.17). The majority of setts within the farm boundary were stated to be accessible by cattle (77.1%; 95% CI 71.2, 83.0%) and 66.8% (95% CI 63.8, 69.7%) of farm boundaries provided opportunities for nose-to-nose contact between cattle. Adoption of bTB related biosecurity measures, especially with regards to purchasing cattle and badger-related measures, was lower than measures related to disinfection and washing.
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Affiliation(s)
- M J H O'Hagan
- Veterinary Sciences Division, Agri-Food and Biosciences Institute, Stoney Road, Belfast BT4 3SD, United Kingdom. Maria.O'
| | - D I Matthews
- Biometrics & Information Systems Branch, Agri-Food and Biosciences Institute, 18A Newforge Lane, Belfast BT9 5PX, United Kingdom
| | - C Laird
- Veterinary Sciences Division, Agri-Food and Biosciences Institute, Stoney Road, Belfast BT4 3SD, United Kingdom
| | - S W J McDowell
- Veterinary Sciences Division, Agri-Food and Biosciences Institute, Stoney Road, Belfast BT4 3SD, United Kingdom
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25
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Rossi G, De Leo GA, Pongolini S, Natalini S, Vincenzi S, Bolzoni L. Epidemiological modelling for the assessment of bovine tuberculosis surveillance in the dairy farm network in Emilia-Romagna (Italy). Epidemics 2015; 11:62-70. [PMID: 25979283 DOI: 10.1016/j.epidem.2015.02.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 02/11/2015] [Accepted: 02/25/2015] [Indexed: 10/23/2022] Open
Abstract
Assessing the performance of a surveillance system for infectious diseases of domestic animals is a challenging task for health authorities. Therefore, it is important to assess what strategy is the most effective in identifying the onset of an epidemic and in minimizing the number of infected farms. The aim of the present work was to evaluate the performance of the bovine tuberculosis (bTB) surveillance system in the network of dairy farms in the Emilia-Romagna (ER) Region, Italy. A bTB-free Region since 2007, ER implements an integrated surveillance strategy based on three components, namely routine on-farm tuberculin skin-testing performed every 3 years, tuberculin skin-testing of cattle exchanged between farms, and post-mortem inspection at slaughterhouses. We assessed the effectiveness of surveillance by means of a stochastic network model of both within-farm and between-farm bTB dynamics calibrated on data available for ER dairy farms. Epidemic dynamics were simulated for five scenarios: the current ER surveillance system, a no surveillance scenario that we used as the benchmark to characterize epidemic dynamics, three additional scenarios in which one of the surveillance components was removed at a time so as to outline its significance in detecting the infection. For each scenario we ran Monte Carlo simulations of bTB epidemics following the random introduction of an infected individual in the network. System performances were assessed through the comparative analysis of a number of statistics, including the time required for epidemic detection and the total number of infected farms during the epidemic. Our analysis showed that slaughterhouse inspection is the most effective surveillance component in reducing the time for disease detection, while routine surveillance in reducing the number of multi-farms epidemics. On the other hand, testing exchanged cattle improved the performance of the surveillance system only marginally.
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Affiliation(s)
- Gianluigi Rossi
- Dipartimento di Bioscienze, Università di Parma, Parco Area delle Scienze 11/A, I-43124 Parma, Italy.
| | - Giulio A De Leo
- Stanford University, Hopkins Marine Station, Pacific Grove, CA 93950, USA
| | - Stefano Pongolini
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia-Romagna, Via dei Mercati, 13/A, Parma I-43122, Italy
| | - Silvano Natalini
- Servizio Veterinario e Igiene Alimenti Assessorato Politiche per la Salute Regione Emilia-Romagna, Viale Aldo Moro 21, Bologna I-40127, Italy
| | - Simone Vincenzi
- Center for Stock Assessment Research, Department of Applied Mathematics and Statistics, University of California, Santa Cruz, CA 95064, USA; Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Via Ponzio 34/5, I-20133 Milan, Italy
| | - Luca Bolzoni
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia-Romagna, Via dei Mercati, 13/A, Parma I-43122, Italy; Department of Biodiversity and Molecular Ecology, Research and Innovation Centre - Fondazione Edmund Mach, San Michele all'Adige, Trento, Italy
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26
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Cowie CE, Marreos N, Gortázar C, Jaroso R, White PCL, Balseiro A. Shared risk factors for multiple livestock diseases: a case study of bovine tuberculosis and brucellosis. Res Vet Sci 2014; 97:491-7. [PMID: 25267287 DOI: 10.1016/j.rvsc.2014.09.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 09/02/2014] [Accepted: 09/08/2014] [Indexed: 11/15/2022]
Abstract
Livestock diseases can result in reduced farm productivity. The bacterial diseases tuberculosis (TB) and brucellosis may share some transmission characteristics which, if managed in common, would result in more cost-effective management. Here, we identify risk factors shared between these diseases using a case-control approach and information theoretic modelling. One-hundred cattle farmers in Atlantic Spain were interviewed about farm characteristics and management practices. The risk factor shared between both diseases was intra- and inter-herd contact between cattle. Disease-specific risk factors were the presence of wildlife for TB, and cattle movement between farms for brucellosis. An integrated approach to disease management needs to consider cattle movement and farm biosecurity, reinforced by an education campaign to increase farmer awareness. This would be likely to bring benefits in reducing both diseases and improve the efficiency of any interventions.
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Affiliation(s)
- C E Cowie
- Environment Department, University of York, Heslington, York YO10 5DD, UK; SaBio-IREC Wildlife Research Institute (CSIC-UCLM-JCCM), Ronda de Toledo s/n., 13005 Ciudad Real, Spain.
| | - N Marreos
- SaBio-IREC Wildlife Research Institute (CSIC-UCLM-JCCM), Ronda de Toledo s/n., 13005 Ciudad Real, Spain
| | - C Gortázar
- SaBio-IREC Wildlife Research Institute (CSIC-UCLM-JCCM), Ronda de Toledo s/n., 13005 Ciudad Real, Spain
| | - R Jaroso
- SaBio-IREC Wildlife Research Institute (CSIC-UCLM-JCCM), Ronda de Toledo s/n., 13005 Ciudad Real, Spain
| | - P C L White
- Environment Department, University of York, Heslington, York YO10 5DD, UK
| | - A Balseiro
- SERIDA, Centro de Biotecnología Animal, Camino de Rioseco, 1225, La Olla, Deva, Gijón, Asturias 33394, Spain
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Bovine tuberculosis in Northern Ireland: Risk factors associated with time from post-outbreak test to subsequent herd breakdown. Prev Vet Med 2014; 116:47-55. [DOI: 10.1016/j.prevetmed.2014.06.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Revised: 04/30/2014] [Accepted: 06/17/2014] [Indexed: 11/21/2022]
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28
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Bekara MEA, Azizi L, Bénet JJ, Durand B. Spatial-temporal Variations of Bovine Tuberculosis Incidence in France between 1965 and 2000. Transbound Emerg Dis 2014; 63:101-13. [PMID: 24735092 DOI: 10.1111/tbed.12224] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Indexed: 11/29/2022]
Abstract
We analysed the spatiotemporal variations of bovine tuberculosis (bTB) incidence between 1965 and 2000 in France at the department level (95 areas). Using a Bayesian space-time model, we studied the association between the evolution of bTB incidence and changes of cattle population structure and of herd management practices. Several spatiotemporal hierarchical Bayesian models were compared, and the deviance information criterion was used to select the best of them. Southern France remained a high-risk area over the analysed period, whereas central and western regions were low-risk areas. Besides the frequency of tuberculin skin testing (fixed according to bTB incidence in the preceding years), four factors were associated with an increased risk of bTB: the average herd density and size, the percentage of dairy cows in the cattle population, and the percentage of permanent grassland in cultivated surfaces area. These four factors are linked to the progressive professionalization and specialization of cattle farming, with the disappearance of family farms and of the intensification of breeding systems (especially in dairy farms after the application of the milk quota system in the 1980s). Both trends probably played a significant role in reducing the risk of bTB in France between 1965 and 2000, besides mandatory detection and control procedures.
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Affiliation(s)
- M E A Bekara
- University Paris-Est, French Agency for Food, Environmental and Occupational Health and Safety (Anses), Epidemiology Unit, Animal Health Laboratory, Maisons-Alfort, France
| | - L Azizi
- Animal Epidemiology Unit, INRA Clermont-Ferrand-Theix/MRC Biostatistics Unit, Cambridge, UK
| | - J-J Bénet
- University Paris Est, National Veterinary School of Alfort (ENVA), EpiMAI unit, Maisons-Alfort, France
| | - B Durand
- University Paris-Est, French Agency for Food, Environmental and Occupational Health and Safety (Anses), Epidemiology Unit, Animal Health Laboratory, Maisons-Alfort, France
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29
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Vial F, Miguel E, T. Johnston W, Mitchell A, Donnelly CA. Bovine Tuberculosis Risk Factors for British Herds Before and After the 2001 Foot-and-Mouth Epidemic: What have we Learned from the TB99 and CCS2005 Studies? Transbound Emerg Dis 2013; 62:505-15. [DOI: 10.1111/tbed.12184] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Indexed: 11/28/2022]
Affiliation(s)
- F. Vial
- Department of Infectious Disease Epidemiology; MRC Centre for Outbreak Analysis and Modelling; School of Public Health; Imperial College London; London UK
| | - E. Miguel
- Department of Infectious Disease Epidemiology; MRC Centre for Outbreak Analysis and Modelling; School of Public Health; Imperial College London; London UK
| | - W. T. Johnston
- Department of Health Sciences; University of York; York UK
| | - A. Mitchell
- Animal Health and Veterinary Laboratories Agency (AHVLA); New Haw Addlestone UK
| | - C. A. Donnelly
- Department of Infectious Disease Epidemiology; MRC Centre for Outbreak Analysis and Modelling; School of Public Health; Imperial College London; London UK
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30
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Mycobacterium bovis infection: Everything but the cow. Vet J 2013; 198:303-4. [DOI: 10.1016/j.tvjl.2013.09.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 09/03/2013] [Indexed: 11/19/2022]
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31
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White PW, Martin SW, De Jong MC, O’Keeffe JJ, More SJ, Frankena K. The importance of ‘neighbourhood’ in the persistence of bovine tuberculosis in Irish cattle herds. Prev Vet Med 2013; 110:346-55. [DOI: 10.1016/j.prevetmed.2013.02.012] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 01/19/2013] [Accepted: 02/03/2013] [Indexed: 01/28/2023]
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32
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Szmaragd C, Green LE, Medley GF, Browne WJ. Factors associated with herd restriction and de-restriction with bovine tuberculosis in British cattle herds. Prev Vet Med 2013; 111:31-41. [PMID: 23608481 DOI: 10.1016/j.prevetmed.2013.03.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 03/15/2013] [Accepted: 03/18/2013] [Indexed: 10/26/2022]
Abstract
The incidence of herd breakdown (HBD) with bovine tuberculosis (bTB) has continued to increase year on year since the 1980s in Great Britain. The management of bTB constitutes a major challenge for government and the cattle industry. Whilst various factors have been implicated with the risk of HBD with bTB, factors involved in recovery are less well described. In this paper, we used a multilevel multistate model to identify the factors affecting the probability of a herd being placed under restriction following a bTB outbreak and the factors involved in those restrictions being lifted. By modelling both transitions within the same model, we control for unobserved herd-specific characteristics, and investigate the frequency of change between the restricted and derestricted states. There were two patterns of herd breakdown: transient (characterised by fast cycling between restricted and derestricted states) and continuous (characterised by rare changes between the two states). The risk of a herd being placed under restriction was dominated by predictors related to cattle movements. The probability of derestriction increased with more regular testing. Some risks affected both transitions, namely loge mean size of neighbouring herds in the test-year, whether the herd bred its own replacements and the foot and mouth disease indicator of whether a bTB test was done between February 2002 and January 2003, possibly because the underlying true state of the herd, as infected or not, meant that these factors increased or reduced the risk of HBD. These results highlight that management of bTB is dependent on the true underlying herd status of bTB infection and that some confusion of the benefits or otherwise of some management practices, e.g. using home bred replacements can be explained by this underlying status.
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Affiliation(s)
- Camille Szmaragd
- School of Veterinary Sciences, University of Bristol, Langford BS40 5DU, UK.
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33
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Beltman M. A novel twist to uterine torsion and abomasal displacement in dairy cows. Vet J 2013; 196:284-5. [PMID: 23294568 DOI: 10.1016/j.tvjl.2012.11.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2012] [Accepted: 11/27/2012] [Indexed: 11/27/2022]
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34
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Green L, Carrique-Mas J, Mason S, Medley G. Patterns of delayed detection and persistence of bovine tuberculosis in confirmed and unconfirmed herd breakdowns in cattle and cattle herds in Great Britain. Prev Vet Med 2012; 106:266-74. [DOI: 10.1016/j.prevetmed.2012.04.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Revised: 04/23/2012] [Accepted: 04/27/2012] [Indexed: 10/28/2022]
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Herd-level risk factors for bovine tuberculosis: a literature review. Vet Med Int 2012; 2012:621210. [PMID: 22966479 PMCID: PMC3395266 DOI: 10.1155/2012/621210] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Accepted: 04/14/2012] [Indexed: 11/17/2022] Open
Abstract
Bovine tuberculosis (TB), caused by Mycobacterium 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.
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