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Shaukat W, de Jong E, McCubbin KD, Biesheuvel MM, van der Meer FJUM, De Buck J, Lhermie G, Hall DC, Kalbfleisch KN, Kastelic JP, Orsel K, Barkema HW. Herd-level prevalence of bovine leukemia virus, Salmonella Dublin and Neospora caninum in Alberta, Canada, dairy herds using ELISA on bulk tank milk samples. J Dairy Sci 2024:S0022-0302(24)00849-X. [PMID: 38825106 DOI: 10.3168/jds.2023-24611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2023] [Accepted: 04/14/2024] [Indexed: 06/04/2024]
Abstract
Endemic infectious diseases remain a major challenge for dairy producers worldwide. For effective disease control programs, up-to-date prevalence estimates are of utmost importance. The objective of this study was to estimate the herd-level prevalence of bovine leukemia virus (BLV), Salmonella Dublin, and Neospora caninum in dairy herds in Alberta, Canada using a serial cross-sectional study design. Bulk tank milk samples from all Alberta dairy farms were collected 4 times, in December 2021 (n = 489), April 2022 (n = 487), July 2022 (n = 487), and October 2022 (n = 480), and tested for antibodies against BLV, S. Dublin, and N. caninum using ELISAs. Herd-level apparent prevalence was calculated as positive samples divided by total tested samples at each time point. A mixed effect modified Poisson regression model was employed to assess the association of prevalence with region, herd size, herd type, and type of milking system. Apparent prevalence of BLV was 89.4, 88.7, 86.9 and 86.9% in December, April, July, and October, respectively, whereas for S. Dublin apparent prevalence was 11.2, 6.6, 8.6, and 8.5%, and for N. caninum apparent prevalence was 18.2, 7.4, 7.8, and 15.0%. For BLV, S. Dublin and N. caninum, a total of 91.7, 15.6, and 28.1% of herds, respectively, were positive at least once, whereas 82.5, 3.6, and 3.0% of herds were ELISA-positive at all 4 times. Compared with the north region, central Alberta had a high prevalence (prevalence ratio (PR) = 1.13) of BLV-antibody positive herds, whereas south Alberta had a high prevalence (PR = 2.56) of herds positive for S. Dublin antibodies. Furthermore, central (PR = 0.52) and south regions (PR = 0.46) had low prevalence of N. caninum-positive herds compared with the north. Hutterite colony herds were more frequently BLV-positive (PR = 1.13) but less frequently N. caninum-positive (PR = 0.47). Large herds (>7,200 L/day milk delivered ∼ > 250 cows) were 1.1 times more often BLV-positive, whereas small herds (≤3,600 L/day milk delivered ∼ ≤ 125 cows) were 3.2 times more often N. caninum-positive. For S. Dublin, Hutterite-colony herds were less frequently (PR = 0.07) positive than non-colony herds only in medium and large stratum but not in small stratum. Moreover, larger herds were more frequently (PR = 2.20) S. Dublin-positive than smaller herds only in non-colony stratum but not in colony stratum. Moreover, N. caninum prevalence was 1.6 times higher on farms with conventional milking systems compared with farms with an automated milking system. These results provide up-to-date information of the prevalence of these infections that will inform investigations of within-herd prevalence of these infections and help in devising evidence-based disease control strategies.
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Affiliation(s)
- Waseem Shaukat
- Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Ellen de Jong
- Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Kayley D McCubbin
- Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada; One Health at UCalgary, University of Calgary, Calgary, Alberta, Canada
| | - Marit M Biesheuvel
- Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
| | | | - Jeroen De Buck
- Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Guillaume Lhermie
- Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada; The Simpson Centre for Food and Agricultural Policy, The School of Public Policy, University of Calgary, Calgary, AB, Canada
| | - David C Hall
- Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
| | | | - John P Kastelic
- Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Karin Orsel
- Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Herman W Barkema
- Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada; One Health at UCalgary, University of Calgary, Calgary, Alberta, Canada; Department of Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
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Velasquez-Munoz A, Castro-Vargas R, Cullens-Nobis FM, Mani R, Abuelo A. Review: Salmonella Dublin in dairy cattle. Front Vet Sci 2024; 10:1331767. [PMID: 38264470 PMCID: PMC10803612 DOI: 10.3389/fvets.2023.1331767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 12/19/2023] [Indexed: 01/25/2024] Open
Abstract
Salmonella enterica serovar Dublin (S. Dublin) is a bacterium host-adapted to cattle with increasing prevalence in dairy facilities. It can severely affect cattle health, producing high morbidity and mortality in young calves and reducing the performance of mature animals. Salmonella Dublin is difficult to control and eradicate from herds, as it can be shed from clinically normal animals. In addition, S. Dublin is a zoonotic bacterium that can be lethal for humans and pose a risk for human and animal health due to its multi-drug resistant characteristics. This review provides an overview of S. Dublin as a pathogen in dairy facilities, the risk factors associated with infection, and current strategies for preventing and controlling this disease. Furthermore, current gaps in knowledge are also discussed.
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Affiliation(s)
- Ana Velasquez-Munoz
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI, United States
- Departamento de Ciencias Veterinarias y Salud Pública, Universidad Católica de Temuco, Temuco, Chile
| | - Rafael Castro-Vargas
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI, United States
| | - Faith M. Cullens-Nobis
- Agriculture and Agribusiness Institute, Michigan State University Extension, Michigan State University, East Lansing, MI, United States
| | - Rinosh Mani
- Veterinary Diagnostic Laboratory, College of Veterinary Medicine, Michigan State University, East Lansing, MI, United States
| | - Angel Abuelo
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI, United States
- Agriculture and Agribusiness Institute, Michigan State University Extension, Michigan State University, East Lansing, MI, United States
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3
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Perry KV, Kelton DF, Dufour S, Miltenburg C, Umana Sedo SG, Renaud DL. Risk factors for Salmonella Dublin on dairy farms in Ontario, Canada. J Dairy Sci 2023; 106:9426-9439. [PMID: 37641251 DOI: 10.3168/jds.2023-23517] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 07/01/2023] [Indexed: 08/31/2023]
Abstract
Salmonella Dublin is an emerging pathogen on dairy farms in Canada. In Ontario, Salmonella Dublin has been increasingly isolated from diagnostic laboratory samples. The objective of this observational cross-sectional study was to identify management practices associated with herd positivity for Salmonella Dublin. A convenience sample of 100 dairy farms was visited in Ontario, Canada, from April to August 2022. Farms were visited once to collect blood samples from 20 heifers between 4 and 24 mo old, sample bulk tank milk, and administer an in-person questionnaire on management practices. An additional bulk tank milk sample was collected before the visit by milk transporters. All bulk tank and serum samples underwent ELISA testing to determine Salmonella Dublin positivity (≥35% positivity on ELISA). Of the 1,990 heifers sampled, 44 (2.2%) animals were seropositive for Salmonella Dublin. At least one seropositive heifer was identified on 24% of participating farms. Based on the bulk tank milk samples collected during both sampling periods, 4% of farms were positive for Salmonella Dublin. Overall, of the 100 farms visited, 25% were classified as Salmonella Dublin positive, meaning at least one serum or bulk tank sample was interpreted as positive. A multivariable logistic regression model identified 5 factors associated with herd-level positivity for Salmonella Dublin. Specifically, introducing purchased animals within the last 2 years increased the likelihood that farms were positive for Salmonella Dublin (odds ratio [OR] = 4.6). Farms that had at least one animal leave the premises for a cattle show, embryo collection center, or loan to another farm and return within the last 2 years were also at a higher risk for Salmonella Dublin (OR = 4.9). Farms that removed manure from the surface of bedding in calving pens twice per month or after every calving were at greater risk for Salmonella Dublin than farms that removed manure less frequently (OR = 8.5). Farms that added bedding material to calving areas once or twice weekly were at lower risk for Salmonella Dublin compared with farms that added bedding less than once weekly (OR = 0.1). In addition, farms that kept 3 cows or less per pen in the calving area were at lower risk for Salmonella Dublin. Test positivity for Salmonella Dublin among Ontario dairy farms sampled is high, and dairy producers should consider avoiding management practices that are associated with an increased risk of Salmonella Dublin infection.
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Affiliation(s)
- K V Perry
- Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - D F Kelton
- Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - S Dufour
- Department of Pathology and Microbiology, Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, QC, Canada H3T 1J4
| | - C Miltenburg
- Ontario Ministry of Agriculture, Food and Rural Affairs, Elora, ON, Canada N1G 4Y2
| | - S G Umana Sedo
- Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - D L Renaud
- Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada N1G 2W1.
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Pedersen L, Houe H, Rattenborg E, Nielsen LR. Semi-Quantitative Biosecurity Assessment Framework Targeting Prevention of the Introduction and Establishment of Salmonella Dublin in Dairy Cattle Herds. Animals (Basel) 2023; 13:2649. [PMID: 37627440 PMCID: PMC10451256 DOI: 10.3390/ani13162649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 08/12/2023] [Accepted: 08/15/2023] [Indexed: 08/27/2023] Open
Abstract
An increasing average herd size and complexity in farm structures call for a higher level of biosecurity. It can reduce the risk of introducing and establishing pathogens with multiple-pathway and indirect spread mechanisms, such as Salmonella Dublin, a pathogen with an increasing occurrence in dairy cattle farms across different countries and continents. Therefore, this study aimed to use existing knowledge to develop a framework with a supporting tool allowing for a time-efficient, yet comprehensive, assessment of biosecurity measures that can help prevent the introduction and establishment of S. Dublin in dairy herds. Based on the literature review, a seven-step biosecurity assessment framework was developed and evaluated in collaboration with biosecurity experts. The resulting framework includes a weighted semi-quantitative assessment method with a scoring guide in an electronic supporting tool for 12 biosecurity sections assessed through on-farm observations and farmer interviews. The framework and tool provide a novel approach to comprehensively assess the overall (mainly external) on-farm biosecurity level by a trained biosecurity assessor. They can be used for systematic data collection in epidemiological studies on risk factors for the introduction and establishment of S. Dublin in dairy farms. Preliminary interrater reliability testing indicated moderate reliability between assessors with varying biosecurity skills.
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Affiliation(s)
- Lars Pedersen
- Department of Veterinary and Animal Sciences, Section for Animal Welfare and Disease Control, University of Copenhagen, 1870 Frederiksberg, Denmark; (H.H.); (L.R.N.)
- SEGES Innovation P/S, 8200 Aarhus, Denmark;
| | - Hans Houe
- Department of Veterinary and Animal Sciences, Section for Animal Welfare and Disease Control, University of Copenhagen, 1870 Frederiksberg, Denmark; (H.H.); (L.R.N.)
| | | | - Liza Rosenbaum Nielsen
- Department of Veterinary and Animal Sciences, Section for Animal Welfare and Disease Control, University of Copenhagen, 1870 Frederiksberg, Denmark; (H.H.); (L.R.N.)
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Henderson K, Mason C, Brülisauer F, Williams P. Determining the prevalence of antibodies to Salmonella Dublin in dairy herds in Great Britain by quarterly bulk tank testing. Prev Vet Med 2022; 208:105776. [DOI: 10.1016/j.prevetmed.2022.105776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 09/30/2022] [Accepted: 10/04/2022] [Indexed: 11/16/2022]
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de Knegt LV, Kudirkiene E, Rattenborg E, Sørensen G, Denwood MJ, Olsen JE, Nielsen LR. Combining Salmonella Dublin genome information and contact-tracing to substantiate a new approach for improved detection of infectious transmission routes in cattle populations. Prev Vet Med 2018; 181:104531. [PMID: 30220483 DOI: 10.1016/j.prevetmed.2018.09.005] [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: 05/16/2018] [Accepted: 09/04/2018] [Indexed: 10/28/2022]
Abstract
This study presents a new method for detection of between-herd livestock movements to facilitate disease tracing and more accurately describe network behaviour of relevance for spread of infectious diseases, including within-livestock business risk-carrying contacts that are not necessarily recorded anywhere. The study introduces and substantiates the concept of grouping livestock herds into business-units based on ownership and location in the tracing analysis of animal movement-based contact networks. To test the utility of this approach, whole core genome sequencing of 196 Salmonella Dublin isolates stored from previous surveillance and project activities was combined with information on cattle movements recorded in the Danish Cattle Database between 1997 and 2017. The aim was to investigate alternative explanations for S. Dublin circulation in groups of herds connected by ownership, but without complete records of livestock movements. The EpiContactTrace R-package was used to trace the contact networks between businesses and compare the network characteristics of businesses sharing strains of S. Dublin with different levels of genetic relatedness. The ownership-only definition proved to be an unreliable grouping approach for large businesses, which could have internal distances larger than 250 km and therefore do not represent useful epidemiological units. Therefore, the grouping was refined using spatial analysis. More than 90% of final business units formed were composed of one single cattle property, whereas multi-property businesses could reach up to eight properties in a given year, with up to 15 cattle herds having been part of the same business through the study period. Results showed markedly higher probabilities of introduction of infectious animals between proposed businesses from which the same clone of S. Dublin had been isolated, when compared to businesses with non-related strains, thus substantiating the business-unit as an important epidemiological feature to consider in contact network analysis and tracing of infection routes. However, this approach may overestimate real-life contacts between cattle properties and putatively overestimate the degree of risk-contacts within each business, since it is based solely on information about property ownership and location. This does not consider administrative and individual farmers behaviours that essentially keep two properties separated. Despite this, we conclude that defining epidemiological units based on businesses is a promising approach for future disease tracing tasks.
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Affiliation(s)
- Leonardo Víctor de Knegt
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Grønnegårdsvej 8, 1870 Frederiksberg C, Denmark.
| | - Eglė Kudirkiene
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Grønnegårdsvej 8, 1870 Frederiksberg C, Denmark
| | | | - Gitte Sørensen
- National Food Institute, Technical University of Denmark, Kemitorvet, Building 204, 2800 Kgs, Lyngby, Denmark
| | - Matthew James Denwood
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Grønnegårdsvej 8, 1870 Frederiksberg C, Denmark
| | - John Elmerdahl Olsen
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Grønnegårdsvej 8, 1870 Frederiksberg C, Denmark
| | - Liza Rosenbaum Nielsen
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Grønnegårdsvej 8, 1870 Frederiksberg C, Denmark
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7
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Queiroz O, Ogunade I, Weinberg Z, Adesogan A. Silage review: Foodborne pathogens in silage and their mitigation by silage additives. J Dairy Sci 2018; 101:4132-4142. [DOI: 10.3168/jds.2017-13901] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 11/27/2017] [Indexed: 11/19/2022]
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8
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Peek SF, Mcguirk SM, Sweeney RW, Cummings KJ. Infectious Diseases of the Gastrointestinal Tract. REBHUN'S DISEASES OF DAIRY CATTLE 2018. [PMCID: PMC7152230 DOI: 10.1016/b978-0-323-39055-2.00006-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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9
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Ågren ECC, Frössling J, Wahlström H, Emanuelson U, Sternberg Lewerin S. A questionnaire study of associations between potential risk factors and salmonella status in Swedish dairy herds. Prev Vet Med 2017. [PMID: 28622788 DOI: 10.1016/j.prevetmed.2017.05.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In this study associations between potential risk factors and salmonella status in Swedish dairy herds were investigated. A case-control study design was used, including existing as well as new cases. Herds were assigned a salmonella status on the basis of antibody analysis of bulk milk samples. Information on potential risk factors was collected from registry data and from farmers via a questionnaire. Univariable and multivariable logistic regression analyses were used to investigate associations between salmonella status and potential risk factors. In addition, multivariate analysis with Additive Bayesian Network (ABN) modelling was performed to improve understanding of the complex relationship between all the variables. Because of the difficulty in identifying associations between potential risk factors and infections with low prevalence and a large regional variation, exposure of potential risk factors in the high-prevalence region (Öland) were compared to exposure in other regions in Sweden. In total 483 of 996 (48%) farmers responded to the questionnaire, 69 herds had test-positive bulk milk samples. The strongest association with salmonella status was 'presence of salmonella test-positive herds <5 km' (OR 4.3, 95% CI 2.0-9.4). Associations with salmonella status were also seen between 'feeding calves residue milk only' (OR 2.4, 95% CI 1.2-4.6), 'certified organic herds' (OR 2.5, 95% CI 1.2-4.9) and 'frequently seeing signs of rodents' (OR 0.4, 95% CI 0.13-0.97). The ABN model showed associations between Öland and four of the variables: salmonella status, presence of test-positive herds <5km, shared pastures and providing protective clothing for visitors. The latter is probably a reflection of increased disease awareness in Öland. The ABN model showed associations between herd size and housing as well as several management procedures. This provides an explanation why herd size frequently has been identified as a risk factor for salmonella by other studies. The study confirms the importance of local transmission routes for salmonella, but does not identify specific components in this local spread. Therefore, it supports the use of a broad biosecurity approach in the prevention of salmonella. In Öland, some potential risk factors are more common than in other parts of Sweden. Theoretically these could contribute to the spread of salmonella, but this was not confirmed in the present study. The study also highlights the difficulty in identifying associations between potential risk factors and infections with low prevalence and large regional variation.
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Affiliation(s)
- Estelle C C Ågren
- Department of Epidemiology and Disease Control, National Veterinary Institute, SE-751 89 Uppsala, Sweden; Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden.
| | - Jenny Frössling
- Department of Epidemiology and Disease Control, National Veterinary Institute, SE-751 89 Uppsala, Sweden; Department of Animal Environment and Health, Swedish University of Agricultural Sciences, P.O. Box 234, SE-532 23 Skara, Sweden.
| | - Helene Wahlström
- Department of Epidemiology and Disease Control, National Veterinary Institute, SE-751 89 Uppsala, Sweden.
| | - Ulf Emanuelson
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden.
| | - Susanna Sternberg Lewerin
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden.
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11
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O'Connor AM, Sargeant JM, Dohoo IR, Erb HN, Cevallos M, Egger M, Ersbøll AK, Martin SW, Nielsen LR, Pearl DL, Pfeiffer DU, Sanchez J, Torrence ME, Vigre H, Waldner C, Ward MP. Explanation and Elaboration Document for the
STROBE
‐Vet Statement: Strengthening the Reporting of Observational Studies in Epidemiology – Veterinary Extension. Zoonoses Public Health 2016; 63:662-698. [DOI: 10.1111/zph.12315] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2016] [Indexed: 01/10/2023]
Affiliation(s)
- A. M. O'Connor
- Department of Veterinary Diagnostic and Production Animal Medicine Iowa State University Ames IA USA
| | - J. M. Sargeant
- Centre for Public Health and Zoonoses University of Guelph Guelph ON Canada
- Department of Population Medicine Ontario Veterinary College Guelph ON Canada
| | - I. R. Dohoo
- Centre for Veterinary Epidemiological Research University of Prince Edward Island Charlottetown PEI Canada
| | - H. N. Erb
- Department of Population Medicine and Diagnostic Sciences Cornell University Ithaca NY USA
| | - M. Cevallos
- Institute of Social and Preventive Medicine University of Bern BernSwitzerland
| | - M. Egger
- Institute of Social and Preventive Medicine University of Bern BernSwitzerland
| | - A. K. Ersbøll
- National Institute of Public Health University of Southern Denmark Copenhagen Denmark
| | - S. W. Martin
- Department of Population Medicine Ontario Veterinary College Guelph ON Canada
| | - L. R. Nielsen
- Section for Animal Welfare and Disease Control University of Copenhagen Copenhagen Denmark
| | - D. L. Pearl
- Department of Population Medicine Ontario Veterinary College Guelph ON Canada
| | - D. U. Pfeiffer
- Department of Production and Population Health Royal Veterinary College London UK
| | - J. Sanchez
- Department of Health Management University of Prince Edward Island Charlottetown PEI Canada
| | - M. E. Torrence
- Food and Drug Administration Center for Food Safety and Applied Nutrition College Park MD USA
| | - H. Vigre
- National Food Institute Technical University of Denmark Lyngby Denmark
| | - C. Waldner
- Department of Large Animal Clinical Sciences Western College of Veterinary Medicine University of Saskatchewan Saskatoon SK Canada
| | - M. P. Ward
- Faculty of Veterinary Science The University of Sydney Sydney NSWAustralia
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12
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O'Connor AM, Sargeant JM, Dohoo IR, Erb HN, Cevallos M, Egger M, Ersbøll AK, Martin SW, Nielsen LR, Pearl DL, Pfeiffer DU, Sanchez J, Torrence ME, Vigre H, Waldner C, Ward MP. Explanation and Elaboration Document for the STROBE-Vet Statement: Strengthening the Reporting of Observational Studies in Epidemiology-Veterinary Extension. J Vet Intern Med 2016; 30:1896-1928. [PMID: 27859752 PMCID: PMC5115190 DOI: 10.1111/jvim.14592] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2016] [Revised: 06/24/2016] [Accepted: 08/29/2016] [Indexed: 01/15/2023] Open
Abstract
The STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) statement was first published in 2007 and again in 2014. The purpose of the original STROBE was to provide guidance for authors, reviewers, and editors to improve the comprehensiveness of reporting; however, STROBE has a unique focus on observational studies. Although much of the guidance provided by the original STROBE document is directly applicable, it was deemed useful to map those statements to veterinary concepts, provide veterinary examples, and highlight unique aspects of reporting in veterinary observational studies. Here, we present the examples and explanations for the checklist items included in the STROBE-Vet statement. Thus, this is a companion document to the STROBE-Vet statement methods and process document (JVIM_14575 "Methods and Processes of Developing the Strengthening the Reporting of Observational Studies in Epidemiology-Veterinary (STROBE-Vet) Statement" undergoing proofing), which describes the checklist and how it was developed.
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Affiliation(s)
- A M O'Connor
- Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, IA
| | - J M Sargeant
- Centre for Public Health and Zoonoses, University of Guelph, Guelph, ON, Canada.,Department of Population Medicine, Ontario Veterinary College, Guelph, ON, Canada
| | - I R Dohoo
- Centre for Veterinary Epidemiological Research, University of Prince Edward Island, Charlottetown, PEI, Canada
| | - H N Erb
- Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, NY
| | - M Cevallos
- Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland
| | - M Egger
- Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland
| | - A K Ersbøll
- National Institute of Public Health, University of Southern Denmark, Copenhagen, Denmark
| | - S W Martin
- Department of Population Medicine, Ontario Veterinary College, Guelph, ON, Canada
| | - L R Nielsen
- Section for Animal Welfare and Disease Control, University of Copenhagen, Copenhagen, Denmark
| | - D L Pearl
- Department of Population Medicine, Ontario Veterinary College, Guelph, ON, Canada
| | - D U Pfeiffer
- Department of Production and Population Health, Royal Veterinary College, London, UK
| | - J Sanchez
- Department of Health Management, University of Prince Edward Island, Charlottetown, PEI, Canada
| | - M E Torrence
- Food and Drug Administration, Center for Food Safety and Applied Nutrition, College Park, MD
| | - H Vigre
- National Food Institute, Technical University of Denmark, Lyngby, Denmark
| | - C Waldner
- Department of Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - M P Ward
- Faculty of Veterinary Science, The University of Sydney, Sydney, Australia
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13
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Ågren EC, Sternberg Lewerin S, Wahlström H, Emanuelson U, Frössling J. Low prevalence of Salmonella in Swedish dairy herds highlight differences between serotypes. Prev Vet Med 2016; 125:38-45. [DOI: 10.1016/j.prevetmed.2015.12.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 12/21/2015] [Accepted: 12/21/2015] [Indexed: 11/30/2022]
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Herd- and individual-level prevalences of and risk factors for Salmonella spp. fecal shedding in dairy farms in Al-Dhulail Valley, Jordan. Trop Anim Health Prod 2015; 47:1241-8. [DOI: 10.1007/s11250-015-0854-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 05/18/2015] [Indexed: 10/23/2022]
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15
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Stockmarr A, Bødker R, Nielsen LR. Dynamic changes in antibody levels as an early warning of Salmonella Dublin in bovine dairy herds. J Dairy Sci 2013; 96:7558-64. [PMID: 24140322 DOI: 10.3168/jds.2012-6478] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 09/09/2013] [Indexed: 11/19/2022]
Abstract
Salmonella Dublin is a bacterium that causes disease and production losses in cattle herds. In Denmark, a surveillance and control program was initiated in 2002 to monitor and reduce the prevalence of Salmonella Dublin. In dairy herds, the surveillance includes herd classification based on bulk tank milk measurements of antibodies directed against Salmonella Dublin at 3-mo intervals. In this study, an "alarm herd" concept, based on the dynamic progression of these repeated measurements, was formulated such that it contains predictive power for Salmonella Dublin herd classification change from "likely free of infection" to "likely infected" in the following quarter of the year, thus warning the farmer 3 mo earlier than the present system. The alarm herd concept was defined through aberrations from a stable development over time of antibody levels. For suitable parameter choices, alarm herd status was a positive predictor for Salmonella Dublin status change in dairy herds, in that alarm herds had a higher risk of changing status in the following quarter compared with nonalarm herds. This was despite the fact that both alarm and nonalarm herds had antibody levels that did not indicate the herds being "likely infected" according to the existing classification system in the present quarter. The alarm herd concept can be used as a new early warning element in the existing surveillance program. Additionally, to improve accuracy of herd classification, the alarm herd concept could be incorporated into a model including other known risk factors for change in herd classification. Furthermore, the model could be extended to other diseases monitored in similar ways.
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Affiliation(s)
- A Stockmarr
- National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, DK-1870 Frederiksberg C, Denmark; Department of Applied Mathematics and Computer Science, Technical University of Denmark, Matematiktorvet, Building 303B, DK-2800 Lyngby, Denmark.
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Nielsen LR, Dohoo I. Time-to-event analysis of predictors for recovery from Salmonella Dublin infection in Danish dairy herds between 2002 and 2012. Prev Vet Med 2013; 110:370-8. [PMID: 23473853 DOI: 10.1016/j.prevetmed.2013.02.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 02/11/2013] [Accepted: 02/12/2013] [Indexed: 11/25/2022]
Abstract
Salmonella Dublin infections reduce gross margins and compromise animal health and welfare in dairy cattle herds. Despite on-going control efforts in several countries the duration and risk factors of a persistent infection have been difficult to study due to a lack of suitable data. This study utilised the unique opportunity to extract systematically collected repeated bulk-tank milk antibody measurements from all the Danish dairy herds during a 10-year period to perform a time-to-event analysis of the factors that affect the duration of test-positivity and the hazards of recovery from S. Dublin at herd level. Recovery was defined as a shift from test-positive to test-negative between two year-quarters followed by at least three more test-negative year-quarters. The average duration of infection was approximately 2 years. Predictors of recovery were tested in a multivariable Cox proportional hazard model allowing herds to recover from infection multiple times over the 10-year surveillance period. The model results were based on 36,429 observations with data on all the predictors, representing 3563 herds with a total of 3246 recoveries. Sixty-seven herds (2.4%) remained test-positive throughout the study period. The rest of the 317 herds that did not have any recoveries were censored, mainly due to a cessation of milk production. Prior recovery from test-positivity turned out not to be a significant predictor of recovery in the model. The effect of the duration of infection on the conditional probability of recovery (i.e. the hazard) was time-dependent: early in the study period, long durations of infection were predictive of a low hazard of recovery. Later in the control programme the effect of duration of infection was reduced indicating a desired effect of an intensified control programme. There was an increasing tendency towards longer durations and lower hazard of recovery with: (i) increasing herd sizes, (ii) increasing bulk-tank milk somatic cell counts, (iii) increasing local prevalence within a 5 km radius, (iv) organic farming and (v) recent purchase of cattle from test-positive herds. Participation in a voluntary paratuberculosis control programme reduced the duration of infection, and there were indications that recovery from S. Dublin infection was stimulated by a centrally organised and targeted control campaign. This is the first large-scale study that investigated duration of infection and predictors of recovery from S. Dublin in cattle herds over an extended period of time. The results provide useful knowledge for the design of control programmes for S. Dublin.
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Affiliation(s)
- Liza Rosenbaum Nielsen
- Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Grønnegårdsvej 8, DK-1870 Frederiksberg C, Denmark.
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Nielsen TD, Green LE, Kudahl AB, Østergaard S, Nielsen LR. Evaluation of milk yield losses associated with Salmonella antibodies in bulk tank milk in bovine dairy herds. J Dairy Sci 2013; 95:4873-4885. [PMID: 22916892 DOI: 10.3168/jds.2011-4332] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Accepted: 04/16/2012] [Indexed: 11/19/2022]
Abstract
The effect of Salmonella on milk production is not well established in cattle. The objective of this study was to investigate whether introduction of Salmonella into dairy cattle herds was associated with reduced milk yield and determine the duration of any such effect. Longitudinal data from 2005 through 2009 were used, with data from 12 mo before until 18 mo after the estimated date of infection. Twenty-eight case herds were selected based on an increase in the level of Salmonella-specific antibodies in bulk-tank milk from <10 corrected optical density percentage (ODC%) to ≥70 ODC% between 2 consecutive three-monthly measurements in the Danish Salmonella surveillance program. All selected case herds were conventional Danish Holstein herds. Control herds (n=40) were selected randomly from Danish Holstein herds with Salmonella antibody levels consistently <10 ODC%. A date of herd infection was randomly allocated to the control herds. Hierarchical mixed effect models with the outcome test-day yield of energy-corrected milk (ECM)/cow were used to investigate daily milk yield before and after the estimated herd infection date for cows in parities 1, 2, and 3+. Control herds were used to evaluate whether the effects in the case herds could be reproduced in herds without Salmonella infection. Herd size, days in milk, somatic cell count, season, and year were included in the models. Yield in first-parity cows was reduced by a mean of 1.4 kg (95% confidence interval: 0.5 to 2.3) of ECM/cow per day from 7 to 15 mo after the estimated herd infection date, compared with that of first-parity cows in the same herds in the 12 mo before the estimated herd infection date. Yield for parity 3+ cows was reduced by a mean of 3.0 kg (95% confidence interval: 1.3 to 4.8) of ECM/cow per day from 7 to 15 mo after herd infection compared with that of parity 3+ cows in the 12 mo before the estimated herd infection. We observed minor differences in yield in second-parity cows before and after herd infection and observed no difference between cows in control herds before and after the simulated infection date. Milk yield decreased significantly in affected herds and the reduction was detectable several months after the increase in bulk tank milk Salmonella antibodies. It took more than 1 yr for milk yield to return to preinfection levels.
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Affiliation(s)
- T D Nielsen
- Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Grønnegårdsvej 8, DK-1870 Frederiksberg C, Denmark.
| | - L E Green
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - A B Kudahl
- Faculty of Agricultural Sciences, Institute of Animal Health and Bioscience, University of Aarhus, Denmark
| | - S Østergaard
- Faculty of Agricultural Sciences, Institute of Animal Health and Bioscience, University of Aarhus, Denmark
| | - L R Nielsen
- Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Grønnegårdsvej 8, DK-1870 Frederiksberg C, Denmark
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Kirchner M, McLaren I, Clifton-Hadley FA, Liebana E, Wales AD, Davies RH. A comparison between longitudinal shedding patterns of Salmonella
Typhimurium and Salmonella
Dublin on dairy farms. Vet Rec 2012; 171:194. [DOI: 10.1136/vr.100865] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- M. Kirchner
- Department of Bacteriology; Animal Health and Veterinary Laboratories Agency; Woodham Lane, New Haw Addlestone Surrey KT15 3NB UK
| | - I. McLaren
- Department of Bacteriology; Animal Health and Veterinary Laboratories Agency; Woodham Lane, New Haw Addlestone Surrey KT15 3NB UK
| | - F. A. Clifton-Hadley
- Department of Bacteriology; Animal Health and Veterinary Laboratories Agency; Woodham Lane, New Haw Addlestone Surrey KT15 3NB UK
| | - E. Liebana
- Department of Bacteriology; Animal Health and Veterinary Laboratories Agency; Woodham Lane, New Haw Addlestone Surrey KT15 3NB UK
| | - A. D. Wales
- Department of Bacteriology; Animal Health and Veterinary Laboratories Agency; Woodham Lane, New Haw Addlestone Surrey KT15 3NB UK
| | - R. H. Davies
- Department of Bacteriology; Animal Health and Veterinary Laboratories Agency; Woodham Lane, New Haw Addlestone Surrey KT15 3NB UK
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Willeberg P, Nielsen LR, Salman M. Designing and evaluating risk-based surveillance systems: Potential unwarranted effects of applying adjusted risk estimates. Prev Vet Med 2012; 105:185-94. [DOI: 10.1016/j.prevetmed.2011.12.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Revised: 12/04/2011] [Accepted: 12/08/2011] [Indexed: 11/28/2022]
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Nielsen LR, Dohoo I. Survival analysis of factors affecting incidence risk of Salmonella Dublin in Danish dairy herds during a 7-year surveillance period. Prev Vet Med 2012; 107:160-9. [PMID: 22749522 DOI: 10.1016/j.prevetmed.2012.06.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 05/14/2012] [Accepted: 06/03/2012] [Indexed: 11/28/2022]
Abstract
A national surveillance programme for Salmonella Dublin, based on regular bulk-tank milk antibody screening and movements of cattle, was initiated in Denmark in 2002. From 2002 to end of 2009 the prevalence of test-positive dairy herds was reduced from 26% to 10%. However, new infections and spread of S. Dublin between herds continued to occur. The objective of this study was to investigate factors affecting incidence risk of S. Dublin infection in Danish dairy herds between 2003 and 2009. Herds were considered at risk when they had been test-negative for at least four consecutive year-quarters (YQs), either at the start of the study period or after recovery from infection. Survival analysis was performed on a dataset including 6931 dairy herds with 118,969 YQs at risk, in which 1523 failures (new infection events) occurred. Predictors obtained from register data were tested in a multivariable, proportional hazard model allowing for recurrence within herds. During October to December the hazard of failures was higher (hazard ratio HR=3.4, P=0.0005) than the rest of the year. Accounting for the delay in bulk-tank milk antibody responses to S. Dublin infection, this indicates that introduction of bacteria was most frequent between July and October. Purchase from test-positive cattle herds within the previous 6 months was associated with higher hazard of failures (HR=2.5, P<0.0001) compared to no purchase and purchase from test-negative herds. Increasing local prevalence, herd size and bulk-tank milk somatic cell counts were also associated with increasing hazard of failures. The effect of prior infection was time-dependent; the hazard of failures was reduced following a logarithmic decline with increasing time at risk. The hazard was markedly higher in herds with prior infections the first year after becoming at risk again, and then approached the hazard in herds without known prior infections 2-3 years after becoming test-negative. This showed that herds with prior infections need to maintain a high level of biosecurity for at least 3 years after becoming test-negative for S. Dublin to prevent recurrence. Furthermore, general recommendations for dairy herds wishing to protect their herds against S. Dublin include avoidance of purchase from and contact to test-positive herds. Large herds, herds with test-positive neighbours and herds with high somatic cell counts need to obtain and maintain a high level of biosecurity.
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Affiliation(s)
- Liza Rosenbaum Nielsen
- Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Grønnegårdsvej 8, DK-1870 Frederiksberg C, Denmark.
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Age-structured dynamic, stochastic and mechanistic simulation model of Salmonella Dublin infection within dairy herds. Prev Vet Med 2012; 105:59-74. [DOI: 10.1016/j.prevetmed.2012.02.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Revised: 02/05/2012] [Accepted: 02/06/2012] [Indexed: 11/23/2022]
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Nielsen T, Vesterbæk I, Kudahl A, Borup K, Nielsen L. Effect of management on prevention of Salmonella Dublin exposure of calves during a one-year control programme in 84 Danish dairy herds. Prev Vet Med 2012; 105:101-9. [DOI: 10.1016/j.prevetmed.2012.01.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Revised: 12/31/2011] [Accepted: 01/18/2012] [Indexed: 11/25/2022]
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Nielsen LR, Nielsen SS. A structured approach to control of Salmonella Dublin in 10 Danish dairy herds based on risk scoring and test-and-manage procedures. Food Res Int 2012. [DOI: 10.1016/j.foodres.2011.02.027] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Ersbøll AK, Nielsen LR. Spatial patterns in surveillance data during control of Salmonella Dublin in bovine dairy herds in Jutland, Denmark 2003-2009. Spat Spatiotemporal Epidemiol 2011; 2:195-204. [PMID: 22748178 DOI: 10.1016/j.sste.2011.07.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Salmonella Dublin is the most commonly isolated Salmonella serotype in Danish cattle and leads to economic and welfare losses in infected herds. Furthermore, it leads to high mortality in human cases. A national surveillance program for Salmonella Dublin was initiated in Denmark in October 2002. This study aimed at modelling the progress and spatial patterns during the control of Salmonella Dublin in dairy herds in the Jutland peninsula in Denmark, especially differences between regions and years. A total of 6331 dairy herds were included during 2003-2009. Antibody measurements of bulk-tank milk samples were used for testing herd-level Salmonella status in these dairy herds. Risk maps were estimated as prevalence intensity maps. Spatial clustering was analysed using scan statistics and SMR was estimated. In 2003, the prevalence of Salmonella Dublin test-positive dairy herds was 24%. It decreased to 12% in 2009. Prevalence intensity maps showed large differences in the reduction of Salmonella Dublin test-positive herds. The number of clusters reduced during the study period. However, throughout the study period two clusters remained significant. Differences were seen in the progress of the control between regions over the years. The implementation and effectiveness of the control program was different between regions. The progress of control was seen to vary not only between regions, but also over time influencing infection dynamics. Thus, recommendations and regionally targeted efforts during control campaigns are needed.
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Affiliation(s)
- Annette Kjær Ersbøll
- University of Southern Denmark, National Institute of Public Health, Øster Farimagsgade 5A, DK-1353 København K, Denmark.
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Nielsen LR, Dohoo I. Culling decisions of dairy farmers during a 3-year Salmonella control study. Prev Vet Med 2011; 100:29-37. [PMID: 21481960 DOI: 10.1016/j.prevetmed.2011.03.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2010] [Revised: 03/10/2011] [Accepted: 03/10/2011] [Indexed: 11/28/2022]
Abstract
Salmonella enterica subsp. enterica-serotypes lead to periodically increased morbidity and mortality in cattle herds. The bacteria can also lead to serious infections in humans. Consequently, Denmark has started a surveillance and control programme in 2002. The programme focuses on Salmonella Dublin which is the most prevalent and most persistent serotype in the Danish cattle population. A field study in 10 dairy herds with persistent Salmonella infections was carried out over three years to gain experience with control procedures including risk assessment, targeted control actions and test-and-cull procedures. From autumn 2003 until end of 2006 quarterly milk quality control samples from all lactating cows and biannual blood samples from all young stock above the age of three months were tested using an indirect antibody ELISA. The most recent and previous test results were used to categorise all animals into risk groups. These risk groups and all individual ELISA-results were communicated to the farmers as colour-coded lists four to six times per year. Farmers were advised to manage the risk of Salmonella transmission from cattle with repeatedly high ELISA results (flagged as "red") or cows with at least one recent moderately high ELISA result (flagged as "yellow") on the lists. Risk management included, e.g. culling or separation of the cows at calving. We analysed culling decisions using two models. For heifers a hierarchical multivariable logistic model with herd as random effect evaluated if animals with red and yellow flags had higher probability of being slaughtered or sold before first calving than animals without any risk flags. For adult cows a semi-parametric proportional hazard survival model was used to test the effect of number of red and yellow flags on hazards of culling at different time points and interactions with prevalence in the herd while accounting for parity, stage of lactation, milk yield, somatic cell count and the hierarchical structure of the data with animals clustered at herd level. This study illustrates how investigation of culling decisions made by herd managers when they have access to test-status of individual animals and overall apparent prevalence during control of an infection can lead to useful new knowledge. Overall herd managers were more likely to cull cattle with increasing number of yellow and red flags than animals with no flags. However, cattle were more likely to be culled with yellow and red flags during times with low or medium high within-herd seroprevalence than at times with high seroprevalence. These results are valuable knowledge for modelling and planning of control strategies and for making recommendations to farmers about control options.
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Affiliation(s)
- L R Nielsen
- Department of Large Animal Sciences, Faculty of Life Sciences, University of Copenhagen, Frederiksberg C, Denmark.
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26
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Prevalence and risk factors for Salmonella in veal calves at Danish cattle abattoirs. Epidemiol Infect 2010; 139:1075-80. [DOI: 10.1017/s0950268810002591] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
SUMMARYThe study's objectives were to determine herd- and animal-level prevalence and herd-level risk factors for Salmonella in dairy-bred veal calves at slaughter in Denmark. In total, 1296 faecal samples were collected at five cattle abattoirs in Denmark during 2007–2008. The animals came from 71 randomly selected specialized veal-calf producers that delivered more than 100 animals to slaughter per year. Salmonella Dublin bacteria were isolated from 19 samples from 12 herds and Salmonella Typhimurium was isolated from one sample. The apparent prevalence of herds delivering Salmonella-shedding animals to slaughter was 18% (95% CI 9–27). The overall estimated true prevalence of shedding calves at slaughter was 1·3%. Veal-calf herds that purchased animals from herds not classified as low risk in the Danish Salmonella surveillance programme had significantly (P=0·03) higher risk of delivering Salmonella-shedding calves to slaughter. The results emphasize the importance of efforts in the dairy industry to ensure food safety for consumers.
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Cummings KJ, Warnick LD, Elton M, Gröhn YT, McDonough PL, Siler JD. The effect of clinical outbreaks of salmonellosis on the prevalence of fecal Salmonella shedding among dairy cattle in New York. Foodborne Pathog Dis 2010; 7:815-23. [PMID: 20353290 DOI: 10.1089/fpd.2009.0481] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The objective of this study was to determine if the within-herd prevalence of fecal Salmonella shedding is higher in dairy herds with clinical outbreaks of disease, as compared to herds with subclinical infections only. Data were collected prospectively from dairy herds throughout New York that had at least 150 lactating cows and that received clinical service from participating veterinarians. After enrollment, Salmonella surveillance consisted of both environmental screening and disease monitoring within the herd. Herds positive by either environmental or fecal culture were sampled during three visits to estimate the within-herd prevalence of Salmonella. We characterized isolates by serovar and antimicrobial resistance pattern. Among 57 enrolled herds, 44 (77%) yielded Salmonella-positive samples during the study period; 27 (61%) of the positive herds had Salmonella isolated from environmental samples only, and 17 (39%) had one or more laboratory-confirmed clinical cases. The within-herd prevalence of fecal Salmonella shedding ranged from 0 to 53%. Salmonella Cerro was the predominant serovar, accounting for 56% of all isolates. Antimicrobial resistance ranged from zero to nine drugs, and 14 (32%) of the positive farms generated multidrug-resistant isolates. Herds with laboratory-confirmed clinical cases had a higher prevalence of fecal Salmonella shedding than herds that only generated positive environmental samples, as estimated by a Poisson regression model (prevalence ratio, 2.7; p = 0.01). An association between dairy herd outbreaks of salmonellosis and a higher prevalence of asymptomatic shedding should help guide strategies for reducing the public health threat of Salmonella, as the ability to recognize high-risk herds by clinical laboratory submissions presents an obvious opportunity to maximize food safety at the preharvest level. This is in contrast with other foodborne zoonotic pathogens, such as Campylobacter jejuni and Escherichia coli O157:H7, which occur widely in adult cattle without accompanying clinical disease.
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Affiliation(s)
- Kevin J Cummings
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, USA.
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Cummings KJ, Warnick LD, Elton M, Rodriguez-Rivera LD, Siler JD, Wright EM, Gröhn YT, Wiedmann M. Salmonella enterica serotype Cerro among dairy cattle in New York: an emerging pathogen? Foodborne Pathog Dis 2010; 7:659-65. [PMID: 20187753 DOI: 10.1089/fpd.2009.0462] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The focus of this study was Salmonella enterica serotype Cerro, a potentially emerging pathogen of cattle. Our objectives were to document the within-herd prevalence of Salmonella Cerro among a sample of New York dairy herds, to describe the antimicrobial resistance patterns and pulsed-field gel electrophoresis types of the isolates, and to elucidate the status of this serotype as a bovine pathogen. Data were collected prospectively from dairy herds throughout New York that had at least 150 lactating cows and that received clinical service from participating veterinarians. Following enrollment, Salmonella surveillance consisted of both environmental screening and disease monitoring within the herd. Herds positive by either environmental or fecal culture were sampled during three visits to estimate the within-herd prevalence of Salmonella. Among 57 enrolled herds, 44 (77%) yielded Salmonella-positive samples during the study period. Of these, 20 herds (46%) were positive for Salmonella Cerro. Upon follow-up sampling for estimation of prevalence, Cerro was identified in 10 of the 20 herds; the median within-herd Cerro prevalence was 17%, with a maximum of 53%. Antimicrobial resistance ranged from zero to nine drugs, and eight (40%) of the Cerro-positive farms generated drug-resistant isolates. Eight XbaI pulsed-field gel electrophoresis types were represented among 116 isolates tested, although 89% of these isolates shared the predominant type. Among herds with clinical cases, cattle that had signs consistent with salmonellosis were more likely to test positive for Cerro than apparently healthy cattle, as estimated by a logistic regression model that controlled for herd as a random effect (odds ratio: 3.9). There is little in the literature concerning Salmonella Cerro, and published reports suggest an absence of disease association in cattle. However, in our region there has been an apparent increase in the prevalence of this serotype among cattle with salmonellosis. Other Salmonella serotypes important to bovine health have emerged to become leading causes of human foodborne disease, and close monitoring of Cerro is warranted.
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Affiliation(s)
- Kevin J Cummings
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, USA.
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Nielsen T, Nielsen L, Toft N, Houe H. Association between bulk-tank milk Salmonella antibody level and high calf mortality in Danish dairy herds. J Dairy Sci 2010; 93:304-10. [DOI: 10.3168/jds.2009-2528] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Accepted: 09/20/2009] [Indexed: 11/19/2022]
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Barkema HW, Green MJ, Bradley AJ, Zadoks RN. Invited review: The role of contagious disease in udder health. J Dairy Sci 2009; 92:4717-29. [PMID: 19762787 DOI: 10.3168/jds.2009-2347] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Contagious diseases are a threat to animal health and productivity, both nationally and at the farm level. This makes implementation of biosecurity measures to prevent their introduction and spread within countries and farms a necessity. Mastitis is the most common and costly contagious disease affecting dairy farms in the western world. The major mastitis pathogens are endemic in most countries, and biosecurity measures to prevent introduction and transmission must therefore be implemented at farm level. The 40-yr-old mastitis control plan remains a solid foundation to prevent the spread of contagious intramammary infections. Contagious diseases that do not affect the mammary gland directly may have an indirect effect on mastitis. This is true for list A diseases such as foot and mouth disease, for which biosecurity measures may need to be taken at national level, and for other infections with nonmastitis pathogens such as bovine viral diarrhea virus and Mycobacterium avium ssp. paratuberculosis. Maintaining a closed herd decreases the risk of introduction of pathogens that affect udder health directly or indirectly. If animals are purchased, their udder health history should be evaluated and they should be examined and tested for contagious diseases. Transmission of infections by and to humans and nonbovine animals may occur. Contact with visitors and nonbovine animals should therefore be minimized. Because of globalization and heightened consumer awareness, the importance of biosecurity now supersedes individual farms, and increased pressure to control transmission of contagious diseases can be expected at industry or government levels in western countries and elsewhere.
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Affiliation(s)
- H W Barkema
- Department of Production Animal Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
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31
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Cummings KJ, Warnick LD, Alexander KA, Cripps CJ, Gröhn YT, McDonough PL, Nydam DV, Reed KE. The incidence of salmonellosis among dairy herds in the northeastern United States. J Dairy Sci 2009; 92:3766-74. [PMID: 19620658 PMCID: PMC7094388 DOI: 10.3168/jds.2009-2093] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The objectives of this study were to estimate the incidence of salmonellosis among a large sample of dairy herds in the northeastern United States (both at the animal level and the herd level), to describe the serotypes and antimicrobial resistance profiles of the positive samples, and to determine whether various herd-level factors were important predictors of incidence. Participating veterinarians enrolled 831 dairy herds and submitted fecal samples from 2,565 female dairy cattle for Salmonella culture because of suspicion of clinical disease. Estimates of animal-level incidence rates were calculated for each age group as the number of cases per animal time at risk, and an estimate of herd-level incidence rate was calculated as the number of positive herds per herd time at risk. Descriptive analysis of serotype data and level of antimicrobial resistance was performed, and Poisson regression analysis was used to study associations between the within-herd incidence of salmonellosis and certain predictor variables (herd size, housing type, vaccination status, and prior history of Salmonella infection). Salmonella was isolated from 576 (22.5%) samples representing 93 herds. The animal-level incidence rates for preweaned female calves, heifers, and adult cows were 8.1, 0.04, and 1.8 cases per 1,000 animal-years, respectively. The herd-level incidence rate was 8.6 positive herds per 100 herd-years. Salmonella Newport was the predominant serotype, accounting for 41% of the cases, followed by Salmonella Typhimurium. Over 68% of all isolates were resistant to 5 or more antimicrobial agents. Herd size was the only significant predictor of the incidence of salmonellosis in a multivariable model; herds with at least 400 female dairy cattle had a higher incidence rate than smaller herds. Our results shed light on the impact of salmonellosis on the dairy industry in the northeastern United States, and they help clarify the role of dairy cattle as a source of Salmonella serotypes that are also important human pathogens.
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Affiliation(s)
- K J Cummings
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
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Adhikari B, Besser T, Gay J, Fox L, Davis M, Cobbold R, Berge A, McClanahan R, Hancock D. Introduction of new multidrug-resistant Salmonella enterica strains into commercial dairy herds. J Dairy Sci 2009; 92:4218-28. [DOI: 10.3168/jds.2008-1493] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Adhikari B, Besser T, Gay J, Fox L, Davis M, Cobbold R, Berge A, Hancock D. The role of animal movement, including off-farm rearing of heifers, in the interherd transmission of multidrug-resistant Salmonella. J Dairy Sci 2009; 92:4229-38. [DOI: 10.3168/jds.2008-1494] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Cummings KJ, Warnick LD, Alexander KA, Cripps CJ, Gröhn YT, James KL, McDonough PL, Reed KE. The duration of fecal Salmonella shedding following clinical disease among dairy cattle in the northeastern USA. Prev Vet Med 2009; 92:134-9. [PMID: 19665243 DOI: 10.1016/j.prevetmed.2009.07.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2008] [Revised: 06/29/2009] [Accepted: 07/07/2009] [Indexed: 11/30/2022]
Abstract
The objectives of this study were to determine the duration of fecal Salmonella shedding among dairy cattle in the northeastern United States following laboratory-confirmed clinical disease and to evaluate whether age group or serotype was associated with either shedding period or mortality. Study farms included 22 dairy herds that had at least two previous salmonellosis cases confirmed by fecal culture. Veterinarians continued to submit culture samples from clinical suspects following herd enrollment, and fecal samples from positive cattle were collected monthly until three sequential negative results were obtained or until loss to follow-up. There were 357 culture-positive clinical cases that each involved a single serotype during the shedding period. The Kaplan-Meier median duration of fecal Salmonella shedding was 50 days, and the maximum was 391 days. S. Newport was the predominant serotype, accounting for 51% of the cases. Age group and serotype were not significant predictors of Salmonella shedding duration in a Cox proportional hazards model, when stratifying by herd. However, the proportion of adult cows shedding for at least two consecutive monthly samples was significantly greater than the proportion of female calves shedding for this duration (Fisher's exact test p-value<0.01). Age group was also associated with mortality in this study; calves with salmonellosis were more likely to die than cows as estimated by a logistic regression model which controlled for herd as a random effect (p-value=0.04).
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Affiliation(s)
- K J Cummings
- Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, NY 14853, United States.
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Wegener HC. Danish initiatives to improve the safety of meat products. Meat Sci 2009; 84:276-83. [PMID: 20374786 DOI: 10.1016/j.meatsci.2009.06.025] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2009] [Revised: 06/11/2009] [Accepted: 06/12/2009] [Indexed: 10/20/2022]
Abstract
During the last two decades the major food safety problems in Denmark, as determined by the number of human patients, has been associated with bacterial infections stemming from meat products and eggs. The bacterial pathogens causing the majority of human infections has been Salmonella and Campylobacter, and to a lesser extent Yersinia, Escherichiacoli O157 and Listeria. Danish initiatives to improve the safety of meat products have focused on the entire production chain from the farm to the consumer, with a special emphasis on the pre-harvest stage of production. The control of bacterial pathogens which are resistant to antibiotics has been a new area of attention in the recent decade, and recently, the increasing globalization of the domestic food supply has called for a complete rethinking of the national food safety strategies. The implementations of a "case-by-case" risk assessment system, as well as increased international collaboration on surveillance, are both elements in this new strategy.
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Affiliation(s)
- Henrik C Wegener
- National Food Institute, Technical University of Denmark, Mørkhøj Bygade 19, DK-2860 Søborg, Denmark.
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Wilhelm B, Rajić A, Waddell L, Parker S, Harris J, Roberts KC, Kydd R, Greig J, Baynton A. Prevalence of Zoonotic or Potentially Zoonotic Bacteria, Antimicrobial Resistance, and Somatic Cell Counts in Organic Dairy Production: Current Knowledge and Research Gaps. Foodborne Pathog Dis 2009; 6:525-39. [DOI: 10.1089/fpd.2008.0181] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Barbara Wilhelm
- Laboratory for Foodborne Zoonoses, Public Health Agency of Canada, Guelph, Ontario, Canada
| | - Andrijana Rajić
- Laboratory for Foodborne Zoonoses, Public Health Agency of Canada, Guelph, Ontario, Canada
- Department of Population Medicine, University of Guelph, Guelph, Ontario, Canada
| | - Lisa Waddell
- Laboratory for Foodborne Zoonoses, Public Health Agency of Canada, Guelph, Ontario, Canada
- Department of Population Medicine, University of Guelph, Guelph, Ontario, Canada
| | - Sarah Parker
- Department of Large Animal Clinical Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Janet Harris
- Laboratory for Foodborne Zoonoses, Public Health Agency of Canada, Guelph, Ontario, Canada
| | - Karen C. Roberts
- Laboratory for Foodborne Zoonoses, Public Health Agency of Canada, Guelph, Ontario, Canada
| | - Robyn Kydd
- Department of Preventive and Social Medicine, University of Otago, Dunedin, New Zealand
| | - Judy Greig
- Laboratory for Foodborne Zoonoses, Public Health Agency of Canada, Guelph, Ontario, Canada
| | - Ashley Baynton
- Laboratory for Foodborne Zoonoses, Public Health Agency of Canada, Guelph, Ontario, Canada
- Department of Population Medicine, University of Guelph, Guelph, Ontario, Canada
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Ersbøll AK, Nielsen LR. The range of influence between cattle herds is of importance for the local spread of Salmonella Dublin in Denmark. Prev Vet Med 2008; 84:277-90. [PMID: 18242741 DOI: 10.1016/j.prevetmed.2007.12.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The objective of the study was to estimate the range of influence between cattle herds with positive Salmonella Dublin herd status. Herd status was a binary outcome of high/low antibody levels to Salmonella Dublin in bulk-tank milk and blood samples collected from all cattle herds in Denmark for surveillance purposes. Two methods were used. Initially, a spatial generalised linear mixed model was developed with an exponential correlation function to estimate the range of influence simultaneously with the effect of potential risk factors. An iteratively reweighted generalised least squares procedure was used as a second method for verifying the range of influence estimates. With this iterative procedure, deviance residuals were calculated based on a generalised linear model and the range of influence was estimated based on the residuals using an exponential semivariogram. The range of influence was estimated for six different regions in Denmark using both methods. The analyses were performed on data collected during 1 year after initiation of the Salmonella Dublin surveillance program providing herd classifications for the 4th year-quarter of 2003 and 2 years later for the 4th year-quarter of 2005. The prevalence of dairy herds with a positive Salmonella Dublin herd classification status in this period had decreased from 22.1 to 17.0%. In non-dairy herds, the prevalence was nearly unchanged during the same period (3.4 and 3.7% in 4th quarter of 2003 and 2005, respectively). For all cattle herds, the range of influence was 2.3-6.4 km in 2003 and 1.5-8.3 km in 2005. There seemed to be no association between the range of influence and the density of herds in the different regions.
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Affiliation(s)
- A K Ersbøll
- University of Copenhagen, Faculty of Life Sciences, Department of Large Animal Sciences, Veterinary Epidemiology, Grønnegårdsvej 8, DK-1870 Frederiksberg C, Denmark.
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Modelling a national programme for the control of foodborne pathogens in livestock: the case of Salmonella Dublin in the Danish cattle industry. Epidemiol Infect 2008; 136:1521-36. [PMID: 18177521 DOI: 10.1017/s0950268807000179] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
A 'virtual hierarchy' model is described for studying the spread of pathogens between herds of livestock. This novel approach to simulating disease has animals, herds, and geographic regions in a national livestock industry arranged as a hierarchy of objects in computer memory. Superimposed on all objects is an infection-recovery cycle, a control programme, and surveillance based on test results and animal movement. The model was applied to predicting progress in the control of Salmonella Dublin in the Danish dairy cattle industry over a 10-year period. More frequent testing of bulk tank milk for antibodies to S. Dublin was less effective than improved herd biosecurity. Restricting cattle movement between regions provided a strong benefit to those regions initially with a low prevalence of infection. Enhanced control within infected herds was of intermediate benefit. A combination of strategies was highly effective although cost and feasibility of this option needs further exploration.
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