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Mayor A, Ishengoma DS, Proctor JL, Verity R. Sampling for malaria molecular surveillance. Trends Parasitol 2023; 39:954-968. [PMID: 37730525 PMCID: PMC10580323 DOI: 10.1016/j.pt.2023.08.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 08/22/2023] [Accepted: 08/23/2023] [Indexed: 09/22/2023]
Abstract
Strategic use of Plasmodium falciparum genetic variation has great potential to inform public health actions for malaria control and elimination. Malaria molecular surveillance (MMS) begins with a strategy to identify and collect parasite samples, guided by public-health priorities. In this review we discuss sampling design practices for MMS and point out epidemiological, biological, and statistical factors that need to be considered. We present examples for different use cases, including detecting emergence and spread of rare variants, establishing transmission sources and inferring changes in malaria transmission intensity. This review will potentially guide the collection of samples and data, serve as a starting point for further methodological innovation, and enhance utilization of MMS to support malaria elimination.
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Affiliation(s)
- Alfredo Mayor
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain; Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique; Department of Physiologic Sciences, Faculty of Medicine, Universidade Eduardo Mondlane, Maputo, Mozambique.
| | - Deus S Ishengoma
- National Institute for Medical Research (NIMR), Dar es Salaam, Tanzania; Faculty of Pharmaceutical Sciences, Monash University, Melbourne, VIC, Australia; Harvard T.H. Chan School of Public Health, Harvard University, Boston, MA, USA
| | - Joshua L Proctor
- Institute for Disease Modeling in Global Health, Bill and Melinda Gates Foundation, Seattle, WA, USA
| | - Robert Verity
- MRC Centre for Global Infectious Disease Analysis, Imperial College, London, UK
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Risk based serological survey of Rift Valley fever in Tunisia (2017-2018). Heliyon 2021; 7:e07932. [PMID: 34522818 PMCID: PMC8427255 DOI: 10.1016/j.heliyon.2021.e07932] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 03/28/2021] [Accepted: 09/01/2021] [Indexed: 12/22/2022] Open
Abstract
Rift Valley fever (RVF) has been reported in the sub-Saharan region of Africa, Egypt and Arabian Peninsula - Yemen and Saudi Arabia, over the past 20 years and is a threat to both the animal and human populations in Tunisia. Tunisia is considered as a high-risk country for the introduction of RVF due to the informal movements of diseased animals already reported in the neighboring countries. The objective of this study was to assess the status of RVF in small ruminants and camels in Tunisia. A risk-based serological survey was conducted to evaluate the presence of RVF based on spatial qualitative risk analysis (SQRA). Samples were collected from small ruminants (sheep and goats) (n = 1,114), and camels (n = 173) samples, belonging to 18 breeders in 14 governorates between November 2017 and January 2018. Samples were tested using an RVF specific multispecies competitive ELISA. Out of the 1,287 samples tested for the presence of RVF IgG antibodies by ELISA, only one positive sample 0.07% (1/1 287) was detected but not confirmed with the virus neutralization test (VNT) used for confirmation. So far, no RVF outbreaks have been reported in Tunisia and our study confirmed the absence of RVF in livestock up to January 2018. Further investigations are needed to confirm the RVF-free status of Tunisia today.
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Gates MC, Earl L, Enticott G. Factors influencing the performance of voluntary farmer disease reporting in passive surveillance systems: A scoping review. Prev Vet Med 2021; 196:105487. [PMID: 34507237 DOI: 10.1016/j.prevetmed.2021.105487] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 07/26/2021] [Accepted: 09/01/2021] [Indexed: 01/06/2023]
Abstract
The impacts of exotic disease incursions on livestock industries can be mitigated by having robust surveillance systems in place that decrease the time between disease introduction and detection. An important component of this is having farmers routinely observe their animals for indications of clinical disease, recognise the existence of problems, and then decide to notify their veterinarian or animal health authorities. However, as highlighted by this literature review, farmers are believed to be underreporting clinical events due to factors such as (1) uncertainty around the clinical signs and situations that warrant reporting, (2) fear over the social and economic consequences from both positive and false positive reports, (3) negative beliefs regarding the efficacy and outcomes of response measures, (4) mistrust and dissatisfaction with animal health authorities, (5) absence of sufficiently attractive financial and non-financial incentives for submitting reports, and (6) poor awareness of the procedures involved with the submission, processing, and response to reports. There have been few formal studies evaluating the efficacy of different approaches to increasing farmer engagement with disease reporting. However, there is a recognised need for any proposed solutions to account for farmer knowledge and experience with assessing their own farm situation as well as the different identities, motivations, and beliefs that farmers have about their role in animal health surveillance systems. Empowering farmers to take a more active role in developing these solutions is likely to become even more important as animal health authorities increasingly look to establish public-private partnerships for biosecurity governance.
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Affiliation(s)
- M Carolyn Gates
- School of Veterinary Science, Massey University, Private Bag 11-222, Palmerston North, 4442, New Zealand.
| | - Lynsey Earl
- Diagnostic and Surveillance Services, Biosecurity New Zealand, Tiakitanga Pūtaiao Aotearoa, Ministry for Primary Industries, Manatū Ahu Matua, PO Box 2526, Wellington, 6140, New Zealand
| | - Gareth Enticott
- Cardiff School of Geography and Planning, Cardiff University, King Edward VII Avenue, Cardiff, CF10 3WA, United Kingdom
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Hunnam JC, Moore KM, Daniel P, Stevenson MA, Salmon SE. Classical swine fever in Victorian domestic pigs: evidence of disease freedom. Aust Vet J 2019; 97:447-451. [PMID: 31475336 DOI: 10.1111/avj.12871] [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: 01/30/2019] [Revised: 07/08/2019] [Accepted: 07/14/2019] [Indexed: 11/27/2022]
Abstract
OBJECTIVE Australia is currently regarded as free of classical swine fever (CSF), a highly contagious disease of pigs caused by a pestivirus. This study aimed to provide additional evidence that the Victorian domestic pig population is free of CSF. DESIGN A structured representative sero-prevalence survey of Victorian domestic pigs at slaughter. METHOD Three-hundred and ninety-one pigs from 23 holdings were sampled at the time of slaughter between March 2016 and October 2017. RESULTS All samples were negative for CSF virus Ab on ELISA. Because of uncertainty in the sensitivity of the CSF Ab ELISA, estimates of the true prevalence of CSF were calculated using Bayesian methods. The median and upper bound of the 95% credible intervals for the true prevalence of CSF was zero when the diagnostic sensitivity of the CSF Ab ELISA was assumed to range from 0.75 to 0.95. CONCLUSION These results provide evidence that the population of domestic pigs in Victoria in 2016-2017 was free of CSF.
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Affiliation(s)
- J C Hunnam
- Chief Veterinary Officer's Unit, Agriculture Victoria, Department of Economic Development, Jobs, Transport and Resources, 475 Mickleham Road, Attwood, Victoria, 3049, Australia
| | - K M Moore
- Chief Veterinary Officer's Unit, Agriculture Victoria, Department of Economic Development, Jobs, Transport and Resources, 475 Mickleham Road, Attwood, Victoria, 3049, Australia
| | - P Daniel
- Chief Veterinary Officer's Unit, Agriculture Victoria, Department of Economic Development, Jobs, Transport and Resources, 475 Mickleham Road, Attwood, Victoria, 3049, Australia
| | - M A Stevenson
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Victoria, 3010, Australia
| | - S E Salmon
- Chief Veterinary Officer's Unit, Agriculture Victoria, Department of Economic Development, Jobs, Transport and Resources, 475 Mickleham Road, Attwood, Victoria, 3049, Australia
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Epidemiological performance and subsequent costs of different surveillance strategies to control bovine herpesvirus type 1 in dairy farms. Prev Vet Med 2017; 139:105-114. [PMID: 28122659 DOI: 10.1016/j.prevetmed.2016.12.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 11/30/2016] [Accepted: 12/03/2016] [Indexed: 11/21/2022]
Abstract
This study aimed at comparing the surveillance program of bovine herpesvirus type 1 (BHV1) as laid down by EU Decision 2004/558/EC and 2007/584/EC ('conventional design') with an alternative design. The alternative design was based on monthly bulk-milk testing, clinical surveillance and a risk-based component that involves testing of animals that are purchased from non-free cattle herds. Scenario-tree analyses were carried out to determine sensitivities of the surveillance system (and its components) and the monthly confidence of freedom on herd-level. Also, the expected costs per surveillance design and components thereof were calculated. Results showed that the conventional (EU) and alternative surveillance designs to obtain a BHV1-free status performed equally well in terms of sensitivity. However, total costs per cattle herd to obtain a free status were highest in the conventional design. In an endemic situation and with a within-herd design prevalence of 10%, the conventional design led to a varying probability of freedom ranging from 99.6% to 100% per month. With the alternative design, in this situation, a constant probability of freedom of >99.9% per month was found. In a disease-free situation, both designs performed equally well (probability of freedom >99.9% per month). The yearly costs per farm for monitoring the disease-free status decreased by approximately 25% in the alternative design. The alternative strategy based on monthly bulk-milk monitoring therefore was deemed most cost-effective. This study showed that the surveillance regime to attain and maintain a BHV1-free status as described by EU-legislation can be improved to reduce the monitoring costs without reduction of the system's sensitivity, given a within-herd design prevalence of 10%. The assessment of various surveillance designs could be highly useful to support decision-making towards a more risk-based approach of animal health surveillance.
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Schärrer S, Widgren S, Schwermer H, Lindberg A, Vidondo B, Zinsstag J, Reist M. Evaluation of farm-level parameters derived from animal movements for use in risk-based surveillance programmes of cattle in Switzerland. BMC Vet Res 2015; 11:149. [PMID: 26170195 PMCID: PMC4499910 DOI: 10.1186/s12917-015-0468-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 07/06/2015] [Indexed: 11/25/2022] Open
Abstract
Background This study focused on the descriptive analysis of cattle movements and farm-level parameters derived from cattle movements, which are considered to be generically suitable for risk-based surveillance systems in Switzerland for diseases where animal movements constitute an important risk pathway. Methods A framework was developed to select farms for surveillance based on a risk score summarizing 5 parameters. The proposed framework was validated using data from the bovine viral diarrhoea (BVD) surveillance programme in 2013. Results A cumulative score was calculated per farm, including the following parameters; the maximum monthly ingoing contact chain (in 2012), the average number of animals per incoming movement, use of mixed alpine pastures and the number of weeks in 2012 a farm had movements registered. The final score for the farm depended on the distribution of the parameters. Different cut offs; 50, 90, 95 and 99 %, were explored. The final scores ranged between 0 and 5. Validation of the scores against results from the BVD surveillance programme 2013 gave promising results for setting the cut off for each of the five selected farm level criteria at the 50th percentile. Restricting testing to farms with a score ≥ 2 would have resulted in the same number of detected BVD positive farms as testing all farms, i.e., the outcome of the 2013 surveillance programme could have been reached with a smaller survey. Conclusions The seasonality and time dependency of the activity of single farms in the networks requires a careful assessment of the actual time period included to determine farm level criteria. However, selecting farms in the sample for risk-based surveillance can be optimized with the proposed scoring system. The system was validated using data from the BVD eradication program. The proposed method is a promising framework for the selection of farms according to the risk of infection based on animal movements.
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Affiliation(s)
- Sara Schärrer
- Veterinary Public Health Institute (VPHI), Vetsuisse Faculty, University of Bern, Bern, Switzerland.
| | | | | | - Ann Lindberg
- National Veterinary Institute (SVA), Uppsala, Sweden.
| | - Beatriz Vidondo
- Veterinary Public Health Institute (VPHI), Vetsuisse Faculty, University of Bern, Bern, Switzerland.
| | - Jakob Zinsstag
- Swiss Tropical and Public Health Institute (Swiss TPH), University of Basel, Basel, Switzerland.
| | - Martin Reist
- Federal Food Safety and Veterinary Office (FSVO), Bern, Switzerland.
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Nathues C, Hillebrand A, Rossteuscher S, Zimmermann W, Nathues H, Schüpbach G. Evaluating the surveillance for swine dysentery and progressive atrophic rhinitis in closed multiplier herds using scenario tree modelling. Porcine Health Manag 2015. [DOI: 10.1186/s40813-015-0001-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Struchen R, Reist M, Zinsstag J, Vial F. Investigating the potential of reported cattle mortality data in Switzerland for syndromic surveillance. Prev Vet Med 2015; 121:1-7. [PMID: 26032722 DOI: 10.1016/j.prevetmed.2015.04.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 04/05/2015] [Accepted: 04/19/2015] [Indexed: 11/16/2022]
Abstract
Systems for the identification and registration of cattle have gradually been receiving attention for use in syndromic surveillance, a relatively recent approach for the early detection of infectious disease outbreaks. Real or near real-time monitoring of deaths or stillbirths reported to these systems offer an opportunity to detect temporal or spatial clusters of increased mortality that could be caused by an infectious disease epidemic. In Switzerland, such data are recorded in the "Tierverkehrsdatenbank" (TVD). To investigate the potential of the Swiss TVD for syndromic surveillance, 3 years of data (2009-2011) were assessed in terms of data quality, including timeliness of reporting and completeness of geographic data. Two time-series consisting of reported on-farm deaths and stillbirths were retrospectively analysed to define and quantify the temporal patterns that result from non-health related factors. Geographic data were almost always present in the TVD data; often at different spatial scales. On-farm deaths were reported to the database by farmers in a timely fashion; stillbirths were less timely. Timeliness and geographic coverage are two important features of disease surveillance systems, highlighting the suitability of the TVD for use in a syndromic surveillance system. Both time series exhibited different temporal patterns that were associated with non-health related factors. To avoid false positive signals, these patterns need to be removed from the data or accounted for in some way before applying aberration detection algorithms in real-time. Evaluating mortality data reported to systems for the identification and registration of cattle is of value for comparing national data systems and as a first step towards a European-wide early detection system for emerging and re-emerging cattle diseases.
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Affiliation(s)
- Rahel Struchen
- Veterinary Public Health Institute, Vetsuisse Faculty, University of Bern, Schwarzenburgstrasse 155, 3003 Bern, Switzerland.
| | - Martin Reist
- Swiss Federal Food Safety and Veterinary Office, Schwarzenburgstrasse 155, 3003 Bern, Switzerland
| | - Jakob Zinsstag
- Swiss Tropical and Public Health Institute, University of Basel, Socinstrasse 57, 4051 Basel, Switzerland
| | - Flavie Vial
- Veterinary Public Health Institute, Vetsuisse Faculty, University of Bern, Schwarzenburgstrasse 155, 3003 Bern, Switzerland
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Schärrer S, Schwermer H, Presi P, Lindberg A, Zinsstag J, Reist M. Cost and sensitivity of on-farm versus slaughterhouse surveys for prevalence estimation and substantiating freedom from disease. Prev Vet Med 2015; 120:51-61. [PMID: 25724077 DOI: 10.1016/j.prevetmed.2015.01.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 01/25/2015] [Accepted: 01/30/2015] [Indexed: 10/24/2022]
Abstract
Within the framework of Swiss surveillance for epizootic diseases, dairy cattle are sampled using bulk tank milk while non-dairy cattle are sampled on the farm. The latter method is costly, time-demanding and dangerous for the personnel. However, slaughterhouses could be an alternative sampling point for this population. To assess the cost-effectiveness and sensitivity of such an approach, surveillance using slaughterhouse sampling was modelled with data from the 2012 Swiss animal movement database (AMD). We simulated a cross-sectional study for bluetongue (BT), and surveillance programmes to substantiate freedom from infectious bovine rhinotracheitis (IBR) and enzootic bovine leucosis (EBL) (combined) to compare the outcome of random on-farm sampling versus slaughterhouse sampling. We found that, under Swiss conditions, slaughterhouse sampling results in low herd-level sensitivities because animals are sent by owners to slaughter individually and not in large groups, restricting the number of samples per herd. This makes slaughterhouse sampling inappropriate for prevalence surveys at the herd-level. However, for prevalence surveys at the animal-level and for substantiation of freedom from disease, slaughterhouse surveillance is equally or more cost-efficient than on-farm sampling.
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Affiliation(s)
- Sara Schärrer
- Veterinary Public Health Institute, University of Berne, Berne, Switzerland.
| | | | - Patrick Presi
- Veterinary Public Health Institute, University of Berne, Berne, Switzerland
| | | | - Jakob Zinsstag
- Swiss Tropical and Public Health Institute, University of Basel, Basel, Switzerland
| | - Martin Reist
- Food Safety and Veterinary Office, Berne, Switzerland
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Raaperi K, Orro T, Viltrop A. Epidemiology and control of bovine herpesvirus 1 infection in Europe. Vet J 2014; 201:249-56. [PMID: 24954868 DOI: 10.1016/j.tvjl.2014.05.040] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 05/30/2014] [Accepted: 05/31/2014] [Indexed: 11/20/2022]
Abstract
Bovine herpesvirus 1 (BHV-1) causes infectious bovine rhinotracheitis (IBR), infectious pustular vulvovaginitis, abortion and balanoposthitis, as well as neurological and systemic disease in cattle. The virus is endemic in cattle populations worldwide although in Europe six countries and several regions in other countries have achieved 'IBR-free' status by implementing control measures. According to European Union (EU) directives, all member states must comply with specific requirements related to BHV-1 infection status in semen and embryos. The requirement that 'IBR-free' states restrict the importation of cattle from endemically infected regions has motivated several European countries to instigate disease eradication programmes. Despite such control measures within the EU, outbreaks of IBR persist in 'IBR-free' states contiguous with infected countries. This review presents a summary of recent research on the epidemiology of BHV-1, highlights the control measures and surveillance systems in place, and discusses the challenges facing eradication schemes.
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Affiliation(s)
- Kerli Raaperi
- Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, Kreutzwaldi 62, Tartu 51014, Estonia.
| | - Toomas Orro
- Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, Kreutzwaldi 62, Tartu 51014, Estonia
| | - Arvo Viltrop
- Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, Kreutzwaldi 62, Tartu 51014, Estonia
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Nöremark M, Widgren S. EpiContactTrace: an R-package for contact tracing during livestock disease outbreaks and for risk-based surveillance. BMC Vet Res 2014; 10:71. [PMID: 24636731 PMCID: PMC3974595 DOI: 10.1186/1746-6148-10-71] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 03/11/2014] [Indexed: 11/10/2022] Open
Abstract
Background During outbreak of livestock diseases, contact tracing can be an important part of disease control. Animal movements can also be of relevance for risk-based surveillance and sampling, i.e. both when assessing consequences of introduction or likelihood of introduction. In many countries, animal movement data are collected with one of the major objectives to enable contact tracing. However, often an analytical step is needed to retrieve appropriate information for contact tracing or surveillance. Results In this study, an open source tool was developed to structure livestock movement data to facilitate contact-tracing in real time during disease outbreaks and for input in risk-based surveillance and sampling. The tool, EpiContactTrace, was written in the R-language and uses the network parameters in-degree, out-degree, ingoing contact chain and outgoing contact chain (also called infection chain), which are relevant for forward and backward tracing respectively. The time-frames for backward and forward tracing can be specified independently and search can be done on one farm at a time or for all farms within the dataset. Different outputs are available; datasets with network measures, contacts visualised in a map and automatically generated reports for each farm either in HTML or PDF-format intended for the end-users, i.e. the veterinary authorities, regional disease control officers and field-veterinarians. EpiContactTrace is available as an R-package at the R-project website (http://cran.r-project.org/web/packages/EpiContactTrace/). Conclusions We believe this tool can help in disease control since it rapidly can structure essential contact information from large datasets. The reproducible reports make this tool robust and independent of manual compilation of data. The open source makes it accessible and easily adaptable for different needs.
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Affiliation(s)
- Maria Nöremark
- Department of Disease Control and Epidemiology, SVA, National Veterinary Institute, 751 89 Uppsala, Sweden.
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Oidtmann B, Peeler E, Lyngstad T, Brun E, Bang Jensen B, Stärk KD. Risk-based methods for fish and terrestrial animal disease surveillance. Prev Vet Med 2013; 112:13-26. [DOI: 10.1016/j.prevetmed.2013.07.008] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 07/08/2013] [Accepted: 07/12/2013] [Indexed: 11/16/2022]
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Frössling J, Ohlson A, Björkman C, Håkansson N, Nöremark M. Application of network analysis parameters in risk-based surveillance - examples based on cattle trade data and bovine infections in Sweden. Prev Vet Med 2012; 105:202-8. [PMID: 22265643 PMCID: PMC7114171 DOI: 10.1016/j.prevetmed.2011.12.011] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Revised: 12/06/2011] [Accepted: 12/11/2011] [Indexed: 11/28/2022]
Abstract
Financial resources may limit the number of samples that can be collected and analysed in disease surveillance programmes. When the aim of surveillance is disease detection and identification of case herds, a risk-based approach can increase the sensitivity of the surveillance system. In this paper, the association between two network analysis measures, i.e. 'in-degree' and 'ingoing infection chain', and signs of infection is investigated. It is shown that based on regression analysis of combined data from a recent cross-sectional study for endemic viral infections and network analysis of animal movements, a positive serological result for bovine coronavirus (BCV) and bovine respiratory syncytial virus (BRSV) is significantly associated with the purchase of animals. For BCV, this association was significant also when accounting for herd size and regional cattle density, but not for BRSV. Examples are given for different approaches to include cattle movement data in risk-based surveillance by selecting herds based on network analysis measures. Results show that compared to completely random sampling these approaches increase the number of detected positives, both for BCV and BRSV in our study population. It is concluded that network measures for the relevant time period based on updated databases of animal movements can provide a simple and straight forward tool for risk-based sampling.
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Affiliation(s)
- Jenny Frössling
- Department of Disease Control and Epidemiology, National Veterinary Institute, SE-751 89 Uppsala, Sweden.
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Reist M, Jemmi T, Stärk KDC. Policy-driven development of cost-effective, risk-based surveillance strategies. Prev Vet Med 2012; 105:176-84. [PMID: 22265642 DOI: 10.1016/j.prevetmed.2011.12.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Revised: 10/27/2011] [Accepted: 12/04/2011] [Indexed: 11/17/2022]
Abstract
Animal health and residue surveillance verifies the good health status of the animal population, thereby supporting international free trade of animals and animal products. However, active surveillance is costly and time-consuming. The development of cost-effective tools for animal health and food hazard surveillance is therefore a priority for decision-makers in the field of veterinary public health. The assumption of this paper is that outcome-based formulation of standards, legislation leaving room for risk-based approaches and close collaboration and a mutual understanding and exchange between scientists and policy makers are essential for cost-effective surveillance. We illustrate this using the following examples: (i) a risk-based sample size calculation for surveys to substantiate freedom from diseases/infection, (ii) a cost-effective national surveillance system for Bluetongue using scenario tree modelling and (iii) a framework for risk-based residue monitoring. Surveys to substantiate freedom from infectious bovine rhinotracheitis and enzootic bovine leucosis between 2002 and 2009 saved over 6 million € by applying a risk-based sample size calculation approach, and by taking into account prior information from repeated surveys. An open, progressive policy making process stimulates research and science to develop risk-based and cost-efficient survey methodologies. Early involvement of policy makers in scientific developments facilitates implementation of new findings and full exploitation of benefits for producers and consumers.
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Affiliation(s)
- M Reist
- Veterinary Public Health Institute, Vetsuisse Faculty, University of Berne, Schwarzenburgstrasse 155, CH-3097 Liebefeld, Switzerland.
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