Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 63
Filtrar
Mais filtros

Bases de dados
Tipo de documento
Intervalo de ano de publicação
1.
Curr Microbiol ; 79(12): 356, 2022 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-36245036

RESUMO

Bovine viral diarrhea virus (BVDV) is an important animal pathogen and has a negative economic impact on cattle industries worldwide. In this study, the BVDV strain named BJ175170 was detected, isolated, and identified from cattle in Beijing, China, during herd screening by BVDV antigen-ELISA and indirect immunofluorescence assay (IFA). To investigate its genomic features, the characteristic 5'UTR region of the isolates were sequenced and BLAST analyzed. BVDV BJ175170 belongs to the BVDV-1c subtype, which differs from the Beijing prevalent BVDV strains. The BVDV particles were further observed by transmission electron microscopy (TEM). To evaluate the virulence of the BVDV BJ175170, the BVDV seronegative rabbits were intraperitoneally inoculated with the virus suspension. Blood samples were analyzed for changes in leukocyte number and antibody titer, and tissue samples were taken for histopathology analysis. These data confirmed again that rabbits could act as the reservoir of BVDV, which poses a small but non-zero risk of re-infection for BVDV-free cattle herds. To our knowledge, this is the first report of pathological changes in rabbits after exposure to BVDV-1c subtype, which could act as experimental reference. Meanwhile, the results of this study indicate that rabbits could act as a potential model for studying the mechanism of BVDV in vivo.


Assuntos
Doença das Mucosas por Vírus da Diarreia Viral Bovina , Vírus da Diarreia Viral Bovina Tipo 1 , Vírus da Diarreia Viral Bovina , Regiões 5' não Traduzidas , Animais , Doença das Mucosas por Vírus da Diarreia Viral Bovina/genética , Doença das Mucosas por Vírus da Diarreia Viral Bovina/prevenção & controle , Bovinos , Diarreia , Vírus da Diarreia Viral Bovina Tipo 1/genética , Vírus da Diarreia Viral Bovina/genética , Filogenia , Coelhos , Virulência
2.
Prev Vet Med ; 204: 105662, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35525066

RESUMO

Countries have implemented control programmes (CPs) for cattle diseases such as bovine viral diarrhoea virus (BVDV) that are tailored to each country-specific situation. Practical methods are needed to assess the output of these CPs in terms of the confidence of freedom from infection that is achieved. As part of the STOC free project, a Bayesian Hidden Markov model was developed, called STOC free model, to estimate the probability of infection at herd-level. In the current study, the STOC free model was applied to BVDV field data in four study regions, from CPs based on ear notch samples. The aim of this study was to estimate the probability of herd-level freedom from BVDV in regions that are not (yet) free. We additionally evaluated the sensitivity of the parameter estimates and predicted probabilities of freedom to the prior distributions for the different model parameters. First, default priors were used in the model to enable comparison of model outputs between study regions. Thereafter, country-specific priors based on expert opinion or historical data were used in the model, to study the influence of the priors on the results and to obtain country-specific estimates. The STOC free model calculates a posterior value for the model parameters (e.g. herd-level test sensitivity and specificity, probability of introduction of infection) and a predicted probability of infection. The probability of freedom from infection was computed as one minus the probability of infection. For dairy herds that were considered free from infection within their own CP, the predicted probabilities of freedom were very high for all study regions ranging from 0.98 to 1.00, regardless of the use of default or country-specific priors. The priors did have more influence on two of the model parameters, herd-level sensitivity and the probability of remaining infected, due to the low prevalence and incidence of BVDV in the study regions. The advantage of STOC free model compared to scenario tree modelling, the reference method, is that actual data from the CP can be used and estimates are easily updated when new data becomes available.


Assuntos
Doença das Mucosas por Vírus da Diarreia Viral Bovina , Doenças dos Bovinos , Vírus da Diarreia Viral Bovina , Animais , Teorema de Bayes , Doença das Mucosas por Vírus da Diarreia Viral Bovina/epidemiologia , Doença das Mucosas por Vírus da Diarreia Viral Bovina/prevenção & controle , Bovinos , Doenças dos Bovinos/epidemiologia , Liberdade
3.
Viruses ; 12(10)2020 09 23.
Artigo em Inglês | MEDLINE | ID: mdl-32977581

RESUMO

Approximately 60% of Australia's beef cattle are located in the vast rangelands of northern Australia. Despite the often low stocking densities and extensive management practices of the observed herd, animal prevalence of BVDV infection and typical rates of transmission are similar to those observed in intensively managed herds in southern Australia and elsewhere in the world. A recent large three- to four-year study of factors affecting the reproductive performance of breeding herds in this region found that where there was evidence of widespread and/or recent BVDV infection, the percentage of lactating cows that became pregnant within four months of calving was reduced by 23%, and calf wastage was increased by 9%. BVDV is now considered the second most important endemic disease affecting beef cattle in northern Australia, costing the industry an estimated AUD 50.9 million annually. Although an effective killed vaccine was released in Australia in 2003, the adoption of routine whole herd vaccination by commercial beef farmers has been slow. However, routine testing to identify persistently infected replacement breeding bulls and heifers has been more widely adopted.


Assuntos
Doença das Mucosas por Vírus da Diarreia Viral Bovina/epidemiologia , Doença das Mucosas por Vírus da Diarreia Viral Bovina/prevenção & controle , Animais , Austrália , Cruzamento , Bovinos , Feminino , Masculino , Prevalência , Vacinação
4.
Prev Vet Med ; 182: 105092, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32745776

RESUMO

Bovine viral diarrhoea virus (BVDV) is a prevalent pathogen in the New Zealand cattle industries, yet few studies to date have evaluated the economics of BVDV in pastoral dairy and beef herds to help inform management decisions. To address this knowledge gap, we developed stochastic individual-based simulation models to represent the transmission dynamics of BVDV in typical spring-calving dairy and beef farms in New Zealand. The models conservatively estimated the direct losses due to a BVDV outbreak at NZ$ 22.22 and NZ$ 41.19 per mixed-age cow per year for a naïve dairy and beef farm, respectively, over a 5-year period. The greatest economic impacts for the dairy farm occurred when persistently infected replacement heifers joined the lactating cow group and caused transient infection of cows to drop in milk production, whereas the greatest impacts for the beef farm was through the loss of fattening stock for sale due to lowered pregnancy rates. Various combinations of diagnostic testing, vaccination, and biosecurity measures were then explored to evaluate the cost-efficiency of different strategies for controlling BVDV at the farm-level. Providing farmers with the estimates of economic impacts of BVDV in their herds may further encourage the uptake of control measures, but close collaboration with a veterinarian to determine the optimal strategy for their unique farm circumstances is still required.


Assuntos
Criação de Animais Domésticos/economia , Doença das Mucosas por Vírus da Diarreia Viral Bovina/prevenção & controle , Controle de Doenças Transmissíveis/economia , Surtos de Doenças/veterinária , Animais , Doença das Mucosas por Vírus da Diarreia Viral Bovina/economia , Doença das Mucosas por Vírus da Diarreia Viral Bovina/epidemiologia , Bovinos , Indústria de Laticínios/economia , Vírus da Diarreia Viral Bovina/fisiologia , Surtos de Doenças/economia , Surtos de Doenças/prevenção & controle , Feminino , Modelos Econômicos , Nova Zelândia/epidemiologia , Prevalência , Processos Estocásticos
5.
J Dairy Sci ; 103(7): 6454-6472, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32359990

RESUMO

A quantitative risk assessment model was developed to estimate the annual probability of introducing bovine viral diarrhea virus (BVDV) and bovine herpesvirus 1 (BoHV-1) at the farm level through animal movements. Data from 2017 official animal movements, biosecurity questionnaires, scientific literature, and expert opinion from field veterinarians were taken into consideration for model input parameters. Purchasing or introducing cattle, rearing replacement heifers offsite, showing cattle at competitions, sharing transport vehicles with other herds, and transporting cattle in vehicles that have not been cleaned and disinfected were considered in the model. The annual probability of introducing BVDV or BoHV-1 through infected animals was very heterogeneous between farms. The median likelihoods of BVDV and BoHV-1introduction were 12 and 9%, respectively. Farms that purchased cattle from within their region (i.e., local movements) and shared transport with other farms had a higher probability for BVDV and BoHV-1 introduction. This model can be a useful tool to support decision-making on biosecurity measures that should be prioritized to reduce the probability of introduction of these 2 diseases in dairy herds.


Assuntos
Doença das Mucosas por Vírus da Diarreia Viral Bovina/prevenção & controle , Controle de Doenças Transmissíveis/métodos , Vírus da Diarreia Viral Bovina , Infecções por Herpesviridae/veterinária , Herpesvirus Bovino 1 , Criação de Animais Domésticos , Animais , Anticorpos Antivirais , Bovinos , Feminino , Infecções por Herpesviridae/prevenção & controle , Medição de Risco
6.
Transbound Emerg Dis ; 66(6): 2426-2439, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31328411

RESUMO

Infection with bovine viral diarrhoea virus (BVDV) is associated with a loss in productivity in cattle farms. Determining which factors influence monetary losses due to BVDV could facilitate the implementation of mitigation measures to reduce the burden of BVDV. Mixed-effect meta-analysis models were performed to estimate the extent to which the costs of mean annual BVDV production losses per animal may be influenced by epidemiological factors such as BVDV introduction risk, initial prevalence, viral circulation intensity and circulation duration (trial 1). Additionally, changes in mean annual BVDV production losses per animal due to specific mitigation measures (i.e., biosecurity, vaccination, testing and culling, cattle introduction or contact with neighbouring cattle herds) were analysed (trial 2). In total, 19 studies were included in the meta-analysis to assess mean annual BVDV production losses. The mean annual direct losses were determined to be €42.14 per animal (trial 1). The multivariate meta-regression showed that four of the previously mentioned epidemiological factors significantly influenced the mean annual BVDV production losses per animal. Indeed, the per animal costs increased to €67.19 when these four factors (trial 1) were considered as "high or moderate" compared to "low". The meta-regression analysis revealed that implementation of vaccination and biosecurity measures were associated with an 8%-12% and 28%-29% decrease in BVDV production losses on average, respectively, when simulated herds were compared with or without such mitigation measures (trial 2). This reduction of mean annual BVDV production losses per animal due to mitigation measures was partially counteracted when farmers brought new cattle on to farm or allowed contact with neighbouring cattle herds. The influencing mitigation factors presented here could help to guide farmers in their decision to implement mitigation strategies for the control of BVDV at farm level.


Assuntos
Doença das Mucosas por Vírus da Diarreia Viral Bovina/economia , Doença das Mucosas por Vírus da Diarreia Viral Bovina/prevenção & controle , Custos e Análise de Custo , Criação de Animais Domésticos/economia , Animais , Doença das Mucosas por Vírus da Diarreia Viral Bovina/epidemiologia , Bovinos , Vírus da Diarreia Viral Bovina , Vacinação/economia
7.
J Vet Med Sci ; 81(4): 577-585, 2019 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-30828031

RESUMO

Bovine viral diarrhea (BVD) is a chronic disease of cattle caused by infection with BVD virus (BVDV) and can result in economic losses within the livestock industry. In Japan, the test and culling policy is a basic control measure, and implementation of an adequate vaccination program is recommended as a national policy. In addition, optional control measures, including compulsory testing of introduced animals and bulk tank milk (BTM) testing as a mass screening method, are used in several provinces, but their efficacy has not been completely assessed. We evaluated these control measures using the scenario tree model of BVD in Japan, developed in the previous study. The model outputs indicated that compulsory testing of all introduced cattle, rather than only heifers and/or non-vaccinated cattle, was cost effective and reduced the risk of BVDV introduction due to animal movement and that BTM testing could effectively monitor most part of the cattle population. Vaccination coverage and BVDV prevalence among introduced cattle could also affect the cost effectiveness of compulsory testing of targeted cattle, particularly under low vaccination coverage or high BVDV prevalence. However, even with the implementation of a highly effective monitoring scheme for many years, BVD risk could not be eliminated; it instead converged at a very low level (0.02%). Disease models with a cost-effective output could be a powerful tool in developing a control scheme for chronic animal diseases, including BVD, with the consent of relevant stakeholders.


Assuntos
Doença das Mucosas por Vírus da Diarreia Viral Bovina/prevenção & controle , Análise Custo-Benefício , Vírus da Diarreia Viral Bovina/isolamento & purificação , Leite/virologia , Animais , Doença das Mucosas por Vírus da Diarreia Viral Bovina/economia , Doença das Mucosas por Vírus da Diarreia Viral Bovina/epidemiologia , Bovinos , Feminino , Japão/epidemiologia , Modelos Estatísticos , Prevalência , Vacinação/veterinária , Vacinas Virais/uso terapêutico
8.
Vet J ; 245: 55-60, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30819426

RESUMO

The outcomes of a voluntary bovine viral diarrhoea virus (BVDV) control programme that has been in place in the Netherlands since 1997 were analysed. This 'BVDV-free' programme was studied in dairy herds in the period 1 August 2007 to 1 August 2013. The programme was based on a test and cull approach at the herd level, after which the BVDV status was monitored by testing young stock for antibodies against BVDV or by antigen testing of newborn calves. One of the challenges of the programme was that, without any legislation or subsidies, farmers had to be motivated to pay all costs involved, with eradication of BVDV from their farm as the only incentive. During the study period, the percentage of dairy farms with a 'BVDV-free' status in the Netherlands increased from 13% to 24%, while the prevalence of active BVDV infections in Dutch dairy herds decreased. This may be related to the increasing number of participants in the 'BVDV-free' programme.


Assuntos
Doença das Mucosas por Vírus da Diarreia Viral Bovina/prevenção & controle , Animais , Anticorpos Antivirais/sangue , Antígenos Virais/sangue , Doença das Mucosas por Vírus da Diarreia Viral Bovina/diagnóstico , Doença das Mucosas por Vírus da Diarreia Viral Bovina/epidemiologia , Bovinos , Indústria de Laticínios/economia , Indústria de Laticínios/métodos , Vírus da Diarreia Viral Bovina/genética , Vírus da Diarreia Viral Bovina/imunologia , Fazendas , Feminino , Leite/virologia , Países Baixos/epidemiologia , Programas Voluntários
9.
Transbound Emerg Dis ; 66(2): 640-652, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30415496

RESUMO

The significant economic impacts of bovine viral diarrhoea (BVD) virus have prompted many countries worldwide to embark on regional or national BVD eradication programmes. Unlike other infectious diseases, BVD control is highly feasible in cattle production systems because the pathogenesis is well understood and there are effective tools to break the disease transmission cycle at the farm and industry levels. Coordinated control approaches typically involve directly testing populations for virus or serological screening of cattle herds to identify those with recent exposure to BVD, testing individual animals within affected herds to identify and eliminate persistently infected (PI) cattle, and implementing biosecurity measures such as double-fencing shared farm boundaries, vaccinating susceptible breeding cattle, improving visitor and equipment hygiene practices, and maintaining closed herds to prevent further disease transmission. As highlighted by the recent DISCONTOOLS review conducted by a panel of internationally recognized experts, knowledge gaps in the control measures are primarily centred around the practical application of existing tools rather than the need for creation of new tools. Further research is required to: (a) determine the most cost effective and socially acceptable means of applying BVD control measures in different cattle production systems; (b) identify the most effective ways to build widespread support for implementing BVD control measures from the bottom-up through farmer engagement and from the top-down through national policy; and (c) to develop strategies to prevent the reintroduction of BVD into disease-free regions by managing the risks associated with the movements of animals, personnel and equipment. Stronger collaboration between epidemiologists, economists and social scientists will be essential for progressing efforts to eradicate BVD from more countries worldwide.


Assuntos
Doença das Mucosas por Vírus da Diarreia Viral Bovina/prevenção & controle , Vírus da Diarreia Viral Bovina/fisiologia , Erradicação de Doenças/métodos , Síndrome Hemorrágica Bovina/prevenção & controle , Animais , Bovinos , Análise Custo-Benefício , Erradicação de Doenças/economia
11.
N Z Vet J ; 66(6): 273-280, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30091684

RESUMO

The major impacts of bovine viral diarrhoea (BVD) on cattle health and production have prompted many countries to embark on national elimination programmes. These programmes typically involve identifying and removing persistently infected (PI) cattle in infected herds and implementing biosecurity measures, such as pre- or post-movement testing. In order to design a systematic national control programme to eliminate BVD in New Zealand, which achieves the greatest benefits to the industries at the lowest cost to individual farmers, an accurate understanding is necessary of the epidemiology, economics and social motivation for BVD control in New Zealand. In this article we briefly review the pathogenesis of BVD, transmission and diagnosis of BVD virus infection, and effectiveness of vaccination. We summarise the current state of knowledge of the prevalence, risk factors for transmission, and financial impacts of BVD in New Zealand. We describe control programmes in Europe and then discuss the challenges that must be addressed to design a cost-effective national control programme to eliminate BVD in New Zealand.


Assuntos
Doença das Mucosas por Vírus da Diarreia Viral Bovina/epidemiologia , Doença das Mucosas por Vírus da Diarreia Viral Bovina/prevenção & controle , Criação de Animais Domésticos , Animais , Doença das Mucosas por Vírus da Diarreia Viral Bovina/diagnóstico , Doença das Mucosas por Vírus da Diarreia Viral Bovina/economia , Bovinos , Vírus da Diarreia Viral Bovina , Europa (Continente) , Feminino , Masculino , Nova Zelândia/epidemiologia , Gravidez , Prevalência , Pesquisa , Fatores de Risco , Vacinas Virais
12.
Ecohealth ; 15(2): 302-316, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29435773

RESUMO

The maintenance of livestock health depends on the combined actions of many different actors, both within and across different regulatory frameworks. Prior work recognised that private risk management choices have the ability to reduce the spread of infection to trading partners. We evaluate the efficiency of farmers' alternative biosecurity choices in terms of their own-benefits from unilateral strategies and quantify the impact they may have in filtering the disease externality of trade. We use bovine viral diarrhoea (BVD) in England and Scotland as a case study, since this provides an example of a situation where contrasting strategies for BVD management occur between selling and purchasing farms. We use an agent-based bioeconomic model to assess the payoff dependence of farmers connected by trade but using different BVD management strategies. We compare three disease management actions: test-cull, test-cull with vaccination and vaccination alone. For a two-farm trading situation, all actions carried out by the selling farm provide substantial benefits to the purchasing farm in terms of disease avoided, with the greatest benefit resulting from test-culling with vaccination on the selling farm. Likewise, unilateral disease strategies by purchasers can be effective in reducing disease risks created through trade. We conclude that regulation needs to balance the trade-off between private gains from those bearing the disease management costs and the positive spillover effects on others.


Assuntos
Criação de Animais Domésticos/métodos , Doença das Mucosas por Vírus da Diarreia Viral Bovina/prevenção & controle , Controle de Doenças Transmissíveis/métodos , Fazendeiros , Gestão de Riscos/métodos , Abate de Animais/economia , Abate de Animais/métodos , Criação de Animais Domésticos/economia , Animais , Doença das Mucosas por Vírus da Diarreia Viral Bovina/transmissão , Bovinos , Controle de Doenças Transmissíveis/economia , Efeitos Psicossociais da Doença , Humanos , Gado , Modelos Econômicos , Gestão de Riscos/economia , Índice de Gravidade de Doença , Reino Unido , Vacinação
13.
Vet J ; 231: 19-29, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29429483

RESUMO

This study evaluated the voluntary and compulsory implementation of a bovine viral diarrhoea virus (BVDV) eradication programme in the Austrian Federal State of Styria, Austria, from an economic point of view using ex-post assessment of costs and benefits (disease losses avoided). An economic net benefit (benefit:cost ratio, BCR=1.18) of the programme was demonstrated during the voluntary programme phase (January 1998-July 2004). The break-even point was reached in 2003. If investments in the compulsory programme (August 2004-December 2016) were taken into account, a net economic loss (BCR=0.16) was demonstrated. In contrast to on-going annual testing of all cattle herds, annual testing in accordance with a revised sampling scheme could reduce total surveillance costs by more than 77%. A Bayesian structural time series model was applied to analyse a hypothesised positive impact of the compulsory BVDV programme on the Styrian cattle export market. The average number of exported cows and bulls increased significantly by 42% (P=0.03) and 47% (P=0.01), respectively, and the producer price increased by 14% (P=0.00) and 5% (P=0.16), respectively, during the compulsory programme period compared with the period prior to intervention. This equates to an average revenue increase of €29,754 for cows and €137,563 for bulls per month. These results justify the implementation of eradication programmes, which initially may not appear to be economically viable, particularly if trade effects are not included in the calculations.


Assuntos
Doença das Mucosas por Vírus da Diarreia Viral Bovina/economia , Doença das Mucosas por Vírus da Diarreia Viral Bovina/prevenção & controle , Análise Custo-Benefício , Erradicação de Doenças/economia , Monitoramento Epidemiológico/veterinária , Programas de Rastreamento/veterinária , Animais , Áustria , Teorema de Bayes , Bovinos , Vírus da Diarreia Viral Bovina/fisiologia , Feminino , Masculino , Programas de Rastreamento/economia
14.
Vaccine ; 36(1): 55-65, 2018 01 02.
Artigo em Inglês | MEDLINE | ID: mdl-29174676

RESUMO

Saponin-based adjuvants are promising adjuvants that enhance both humoral and T-cell-mediated immunity. One of the most used natural products as vaccine adjuvants are Quillaja saponaria bark saponins and its fraction named Quil A®. Despite that, its use has been restricted for human use due to safety issues. As an alternative, our group has been studying the congener species Quillaja brasiliensis saponins and its performance as vaccine adjuvants, which have shown to trigger humoral and cellular immune responses comparable to Quil A® but with milder side effects. Here, we studied a semi purified aqueous extract (AE) and a previously little characterized saponin-enriched fraction (QB-80) from Q. brasiliensis as vaccine adjuvants and an inactivated virus (bovine viral diarrhea virus, BVDV) antigen co-formulated in experimental vaccines in mice model. For the first time, we show the spectra pattern of the Q. brasiliensis saponins by MALDI-TOF, a novel and cost-effective method that could be used to characterize different batches during saponins production. Both AE and QB-80 exhibited noteworthy chemical similarities to Quil A®. In addition, the haemolytic activity and toxicity were assessed, showing that both AE and QB-80 were less toxic than Quil A®. When subcutaneously inoculated in mice, both fractions promoted long-term strong antibody responses encompassing specific IgG1 and IgG2a, enhanced the avidity of IgG antibodies, induced a robust DTH reaction and significantly increased IFN-É£ production in T CD4+ and T CD8+ cells. Furthermore, we have proven herein that AE has the potential to promote dose-sparing, substantially reducing the dose of antigen required for the BVDV vaccines and still eliciting a mixed Th1/Th2 strong immune response. Based on these results, and considering that AE is a raw extract, easier and cheaper to produce than commercially available saponins, this product can be considered as candidate to be escalated from experimental to industrial uses.


Assuntos
Doença das Mucosas por Vírus da Diarreia Viral Bovina/imunologia , Imunidade Celular/imunologia , Extratos Vegetais/imunologia , Quillaja/química , Saponinas/imunologia , Vacinas Virais/imunologia , Adjuvantes Imunológicos/administração & dosagem , Adjuvantes Imunológicos/efeitos adversos , Adjuvantes Imunológicos/química , Animais , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Formação de Anticorpos/imunologia , Doença das Mucosas por Vírus da Diarreia Viral Bovina/prevenção & controle , Linfócitos T CD8-Positivos , Bovinos , Vírus da Diarreia Viral Bovina Tipo 1/imunologia , Relação Dose-Resposta Imunológica , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Camundongos , Extratos Vegetais/administração & dosagem , Extratos Vegetais/efeitos adversos , Extratos Vegetais/química , Folhas de Planta/química , Saponinas de Quilaia/administração & dosagem , Saponinas de Quilaia/efeitos adversos , Saponinas de Quilaia/imunologia , Saponinas/química , Saponinas/economia , Saponinas/isolamento & purificação , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Equilíbrio Th1-Th2 , Vacinas Virais/administração & dosagem
15.
Prev Vet Med ; 145: 1-6, 2017 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-28903865

RESUMO

Since 2008, the Swiss veterinary service has been running a mandatory eradication program for Bovine Viral Diarrhea (BVD) that is focused on detecting and eliminating persistently infected (PI) animals. Detection was initially based on antigen testing from ear tag samples of the entire cattle population, followed by antigen testing of all newborn calves until 2012. Since then, bulk milk serology (dairy herds) and blood sample serology (beef herds) have been used for the surveillance of disease-free herds. From 2008 to 2012, the proportion of newborn PI calves decreased from 1.4% to less than 0.02%. However, this success was associated with substantial expenditures. The aim of this study was to conduct an economic evaluation of the BVD eradication program in the Swiss dairy sector. The situation before the start of the program (herd-level prevalence: 20%) served as a baseline scenario. Production models for three dairy farm types were used to estimate gross margins as well as net production losses and expenditures caused by BVD. The total economic benefit was estimated as the difference in disease costs between the baseline scenario and the implemented eradication program and was compared to the total eradication costs in a benefit-cost analysis. Data on the impact of BVD virus (BVDV) infection on animal health, fertility and production parameters were obtained empirically in a retrospective epidemiological case-control study in Swiss dairy herds and complemented by literature. Economic and additional production parameters were based on benchmarking data and published agricultural statistics. The eradication costs comprised the cumulative expenses for sampling and diagnostics. The economic model consisted of a stochastic simulation in @Risk for Excel with 20,000 iterations and was conducted for a time period of 14 years (2008-2021). The estimated annual financial losses in BVDV infected herds were CHF 85-89 per dairy cow and CHF 1337-2535 for an average farm, depending on the production type. The median net present value (NPV) was estimated at CHF 44.9 million (90% central range: CHF 13.4 million-69.4 million) and the break-even point to have been reached in 2015. Overall, the outcomes demonstrate that the Swiss BVD eradication program results in a net benefit for the dairy sector. These findings are relevant for planning similar BVD control programs in other countries.


Assuntos
Doença das Mucosas por Vírus da Diarreia Viral Bovina/economia , Doença das Mucosas por Vírus da Diarreia Viral Bovina/prevenção & controle , Animais , Animais Recém-Nascidos , Doença das Mucosas por Vírus da Diarreia Viral Bovina/diagnóstico , Estudos de Casos e Controles , Bovinos , Análise Custo-Benefício , Vírus da Diarreia Viral Bovina , Feminino , Estudos Retrospectivos , Fatores de Risco
16.
Vet Rec ; 181(13): 347, 2017 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-28851755

RESUMO

Bovine viral diarrhoea (BVD) is a significant drain on efficient and successful cattle production in both dairy and beef systems around the world. Several countries have achieved eradication of this disease, but always through the motivation of stakeholders who accept the benefits of eradication. These include increased cattle welfare and fitness of cattle to withstand other diseases, and decreased costs of production, the latter resulting from both decreased costs spent on managing the disease and decreased losses. This paper provides a systematic review of 31 papers, published between 1991 and 2015, that address the economic impact of BVD. Each paper takes a different approach, in either beef or dairy production or both. However with the breadth of work collated, a stakeholder engaged in BVD eradication should find an economic figure of most relevance to them. The reported economic impact ranges from £0 to £552 per cow per year (£2370 including outliers). This range represents endemic or subclinical disease situations seen in herds with stable BVD virus infection, and epidemic or severe acute situations, most often seen in naïve herds. The outcome of infection is therefore dependent on the immune status of the animal and severity of the strain. The variations in figures for the economic impact of BVD relate to these immune and pathogenicity factors, along with the variety of impacts monitored.


Assuntos
Doença das Mucosas por Vírus da Diarreia Viral Bovina , Fazendeiros , Médicos Veterinários , Animais , Doença das Mucosas por Vírus da Diarreia Viral Bovina/economia , Doença das Mucosas por Vírus da Diarreia Viral Bovina/epidemiologia , Doença das Mucosas por Vírus da Diarreia Viral Bovina/prevenção & controle , Bovinos , Diarreia , Vírus da Diarreia Viral Bovina , Feminino
17.
Prev Vet Med ; 137(Pt A): 77-92, 2017 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-28040270

RESUMO

Infection with bovine viral diarrhea virus (BVDV) results in major economic losses either directly through decreased productive performance in cattle herds or indirectly, such as through expenses for control programs. The aim of this systematic review was to review financial and/or economic assessment studies of prevention and/or mitigation activities of BVDV at national, regional and farm level worldwide. Once all predefined criteria had been met, 35 articles were included for this systematic review. Studies were analyzed with particular focus on the type of financially and/or economically-assessed prevention and/or mitigation activities. Due to the wide range of possible prevention and/or mitigation activities, these activities were grouped into five categories: i) control and/or eradication programs, ii) monitoring or surveillance, iii) prevention, iv) vaccination and v) individual culling, control and testing strategies. Additionally, the studies were analyzed according to economically-related variables such as efficiency, costs or benefits of prevention and/or mitigation activities, the applied financial and/or economic and statistical methods, the payers of prevention and/or mitigation activities, the assessed production systems, and the countries for which such evaluations are available. Financial and/or economic assessments performed in Europe were dominated by those from the United Kingdom, which assessed mostly vaccination strategies, and Norway which primarily carried out assessments in the area of control and eradication programs; whereas among non-European countries the United States carried out the majority of financial and/or economic assessments in the area of individual culling, control and testing. More than half of all studies provided an efficiency calculation of prevention and/or mitigation activities and demonstrated whether the inherent costs of implemented activities were or were not justified. The dairy sector was three times more likely to be assessed by the countries than beef production systems. In addition, the dairy sector was approximately eight times more likely to be assessed economically with respect to prevention and/or mitigation activities than calf and youngstock production systems. Furthermore, the private sector was identified as the primary payer of prevention and/or mitigation activities. This systematic review demonstrated a lack of studies relating to efficiency calculations, in particular at national and regional level, and the specific production systems. Thus, we confirmed the need for more well-designed studies in animal health economics in order to demonstrate that the implementation and inherent costs of BVDV prevention and/or mitigation activities are justified.


Assuntos
Doença das Mucosas por Vírus da Diarreia Viral Bovina/economia , Vírus da Diarreia Viral Bovina , Animais , Doença das Mucosas por Vírus da Diarreia Viral Bovina/prevenção & controle , Bovinos , Custos e Análise de Custo
18.
J Dairy Sci ; 98(11): 7699-716, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26364098

RESUMO

Bovine viral diarrhea virus (BVDV) is an important endemic infection. However, no information was available on whether it would be economically beneficial to implement a national control program in the Netherlands. Therefore, a stochastic simulation model was developed in which control scenarios were added to compare the epidemiological and economic consequences of BVDV control in Dutch dairy herds in the next 10 yr. In the epidemiological part of the model, herds could be classified as susceptible, infectious, recovered, or vaccinated. The outputs of the epidemiological module served as input for the economic module. Net costs that could be attributed to bovine viral diarrhea consisted of production losses, costs for testing, and culling persistently infected cattle in the present voluntary Dutch BVDV control program and costs for vaccination. Four different control scenarios were simulated, involving testing and culling of persistently infected (based on serum or ear-notch testing), and monitoring BVDV statuses and vaccination and were derived from BVDV control programs that are currently executed in Europe. The costs and benefits of BVDV control in the current situation and in each of the simulated control scenarios were evaluated assuming an annual discount rate of 2%. The model estimated a mean BVDV herd prevalence of 18.0% in 2014 and showed a slightly decreasing prevalence over time. The outputs seemed realistic for the present situation in the Netherlands when compared with actual survey data. The average annual net costs associated with bovine viral diarrhea were estimated at €27.8 million for the dairy industry. Two control scenarios were beneficial in controlling BVDV during the study period (between 2015 and 2025). In the scenario where tracing and removing of PI animals and monitoring of the subsequent status was obligatory, the benefit to cost (B/C) ratio was 1.5 (€1.5 benefit for each invested euro). In the scenario in which the BVDV status of all herds was determined, followed by voluntary measures before control measures became obligatory, the B/C ratio was 1.1. The B/C ratio of the scenarios included could be even higher when it was assumed that nondairy herds participated in the control program as well. The model provided the opportunity to compare the effect of voluntary and mandatory control scenarios on the BVDV prevalence and costs and benefits relative to the current situation in the Netherlands. The model was used to support policy makers in their decisions about a BVDV control program.


Assuntos
Doença das Mucosas por Vírus da Diarreia Viral Bovina/economia , Doença das Mucosas por Vírus da Diarreia Viral Bovina/prevenção & controle , Custos e Análise de Custo , Vírus da Diarreia Viral Bovina/isolamento & purificação , Animais , Doença das Mucosas por Vírus da Diarreia Viral Bovina/epidemiologia , Bovinos , Tomada de Decisões , Modelos Econômicos , Países Baixos/epidemiologia , Prevalência , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Vacinação/economia
19.
Vet Clin North Am Food Anim Pract ; 31(3): 367-80, vi, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26210765

RESUMO

Bovine viral diarrhea virus (BVDv) is associated with bovine respiratory disease complex and other diseases of feedlot cattle. Although occasionally a primary pathogen, BVDv's impact on cattle health is through the immunosuppressive effects of the virus and its synergism with other pathogens. The simple presence or absence of BVDv does not result in consistent health outcomes because BVDv is only one of many risk factors that contribute to disease syndromes. Current interventions have limitations and the optimum strategy for their uses to limit the health, production, and economic costs associated with BVDv have to be carefully considered for optimum cost-effectiveness.


Assuntos
Criação de Animais Domésticos , Complexo Respiratório Bovino/prevenção & controle , Doença das Mucosas por Vírus da Diarreia Viral Bovina/prevenção & controle , Vírus da Diarreia Viral Bovina/isolamento & purificação , Comportamento Alimentar , Animais , Complexo Respiratório Bovino/economia , Complexo Respiratório Bovino/transmissão , Doença das Mucosas por Vírus da Diarreia Viral Bovina/economia , Doença das Mucosas por Vírus da Diarreia Viral Bovina/transmissão , Bovinos , Reservatórios de Doenças/veterinária , Risco
20.
Anim Health Res Rev ; 16(1): 78-82, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26050576

RESUMO

Programs for control and eradication of bovine viral diarrhea virus (BVDV) are often considered prudent when the expense of a control program within a specified time frame effectively prevents loss due to disease and the expense of control does not exceed the costs associated with infection. In some geographic areas, concerns about animal welfare or desires to reduce antibiotic usage may motivate BVDV control even when control programs are associated with a lack of financial return on investment. In other geographic areas, concerns about financial return on investment may be the key motivating factor in considering implementation of BVDV control programs. Past experiences indicate that systematic, well-coordinated control programs have a clear potential for success, while voluntary control programs in cultures of distributed decision-making often result in notable initial progress that ultimately ends in dissolution of efforts. Segmentation of the cattle industry into cow-calf producers, stocker/backgrounders, and feedlot operators amplifies the distribution of decision-making regarding control programs and may result in control measures for one industry segment that are associated with significant costs and limited rewards. Though the host range of BVDV extends well beyond cattle, multiple eradication programs that focus only on testing and removal of persistently infected (PI) cattle have proven to be effective in various countries. While some individuals consider education of producers to be sufficient to stimulate eradication of BVDV, research surrounding the adoption of innovative health care procedures suggests that the process of adopting BVDV control programs has a social element. Collegial interactions and discussions may be crucial in facilitating the systematic implementation necessary to optimize the long-term success of control programs. Compulsory control programs may be considered efficient and effective in some regions; however, in a nation where individual identification of cattle remains voluntary, the likelihood of effective compulsion to control BVDV within a farm or ranch appears to be very unlikely. While currently available diagnostic tests are sufficient to support BVDV eradication via systematic, well-coordinated programs, the development of a diagnostic procedure to safely and consistently detect the gestation of a PI fetus after 5 months of gestation would be a valuable research breakthrough. This desired testing modality would allow diagnosis of PI calves, while the dam continues to provide biocontainment of the infected fetus. This development could speed the progress of control programs in achieving the goal of BVDV control and eventual eradication.


Assuntos
Doença das Mucosas por Vírus da Diarreia Viral Bovina/prevenção & controle , Controle de Doenças Transmissíveis/organização & administração , Animais , Bovinos , Controle de Doenças Transmissíveis/economia , Vírus da Diarreia Viral Bovina/isolamento & purificação , Programas de Rastreamento/veterinária , Estados Unidos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA