Bovine viral diarrhoea virus control in Finland 1998–2004

Abstract. Several European countries have initiated national and regional control-and-eradication campaigns for bovine viral diarrhea virus (BVDV). Most of these campaigns do not involve the use of vaccines; in Germany, vaccination is used only in states in which it is considered necessary because of high BVDV prevalence. In European countries without organized BVDV control programs, vaccination is commonly used to control BVDV. Diagnostic test strategies are fundamental to all control-and-eradication campaigns; therefore, the purpose of this review is to describe how the available diagnostic tests are combined into test strategies in the various phases of control-and-eradication campaigns in Europe. Laboratory techniques are available for BVDV diagnosis at the individual animal level and at the herd level. These are strategically used to achieve 3 main objectives: 1) initial tests to classify herd status, 2) follow-up tests to identify individual BVDV-infected animals in infected herds, and 3) continued monitoring to confirm BVDVfree status. For each objective or phase, the validity of the diagnostic tests depends on the mode of BVDV introduction and duration of infection in test-positive herds, and on how long noninfected herds have been clear of BVDV. Therefore, the various herd-level diagnostic tools-such as antibody detection in bulk milk or in blood samples from young stock animals, or BVDV detection in bulk milk-need to be combined appropriately to obtain effective strategies at low cost. If the individual diagnostic tests are used with due consideration of the objectives of a specific phase of a BVDV control program, they are effective tools for controlling and eradicating BVDV in regions not using vaccination and where vaccination is a part of the control or eradication program.

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“…38,44 In herds with . 50% antibody-positive animals, the seronegative animals were tested for virus.…”

Section: Herd Reinfection If a Pi Animal Or A Dam Carrying A Pimentioning

confidence: 99%

Test Strategies in Bovine Viral Diarrhea Virus Control and Eradication Campaigns in Europe

Houe¹,

Lindberg

Moennig³

2006

J VET Diagn Invest

166

140

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“…Regardless of the prerequisites like legal support and varying initial prevalences of herds with PI animals, it has taken the Scandinavian countries approximately ten years to reach their final phases (Hult and Lindberg, 2005;Nyberg et al, 2004;Rikula et al, 2005;Voss, 2004). …”

Section: Introductionmentioning

confidence: 99%

BVD eradication in Switzerland—A new approach

Presi

Heim

2010

Veterinary Microbiology

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Diverse concepts for BVD eradication or control have been applied in several countries with varying success. Results of previous studies conducted in Switzerland have shown that the prevalence of antibody-positive animals is high and that BVDV is wide spread in the country causing serious economic losses. A new approach to eradicate BVD in the cattle population in Switzerland was chosen. It consists in testing the whole Swiss cattle population for virus detection in a short period of time, without initial antibody screening.Identified persistently infected (PI) animals have to be slaughtered, and new herd infections should be avoided by movement restrictions. Ear-notches are collected using special tags for labeling the animals, and are analyzed using ELISA or rtRT-PCR Methods. Confirmatory tests if needed are performed on blood samples using rtRT-PCR.The eradication program is divided in four phases: 1) Pre-pasturing phase: all young bovines going to transhumance in summer have to be negative tested before. 2) Initial phase: all non-tested bovines have to be tested. Movement restrictions are effective at the same time. 3) Calves phase: all new-borne calves have to be tested 4) Surveillance phase: several strategies will be compared using a modeling approach.After the pre-pasture phase already 595'230 animals (37% of the livestock) have been tested within four months. A prevalence of 1.1% of PI's was observed. The average age of infected animals is 403 days compared to 794 days for non-infected animals, with the oldest PI animal being over 11 years old. On average PI animals are slaughtered within 18 days after the last positive result.The pre-pasture phase has shown that sampling and testing a high number of animals in a short time is challenging but possible. The next phase will deal with a double amount of animals in a similar time frame. The coordination between all partners as well as the collaboration of farmers is the key factor for ensuring the success of the program.

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“…This situation could be erroneously interpreted as a recently acquired infection. Such discrepancies could be explained by varying contributions of individual cows to the BTM, different milk yields of antibody negative and positive cows or could even reflect the incorporation of new seropositive animals (Rikula et al 2005) in farms that were less committed to the control program. These factors should therefore be considered when interpreting BTM Ab-ELISA results, especially if the farm in question is small.…”

Section: Discussionmentioning

confidence: 99%

Monitoring bovine viral diarrhea virus (BVDV) infection status in dairy herds

Dieguez¹,

Yus²,

Sanjuán³

et al. 2008

Pesq. Vet. Bras.

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588Pesq. Vet. Bras. 28(12):588-592, dezembro 2008 RESUMO.-[Monitoramento do estado de infecção pelo vírus da diarrhéia viral bovina (BVDV) em rebanhos bovinos leiteiros.] Os objetivos do presente estudo foram avaliar a relação entre os níveis de anticorpos frente ao vírus da diarréia viral bovina (BVDV) no tanque de leite e a prevalência de animais seropositivos em cada rebanho; e também avaliar a eficiência da medição dos ní-veis de anticorpos no tanque de leite como método de monitoramento do status de infecção frente ao BVDV. Nos rebanhos estudados, obtiveram-se amostras de soro de todos os animais com idade superior a um ano, assim como uma amostra de tanque coletivo de leite. As amostras de soro e leite foram analisados por um teste ELISA de bloqueio baseado na detecção de anticorpos anti-p80. Posteriormente coletaram-se mais duas amostras do tanque de leite em cada exploração com intervalos de nove meses entre as coletas. This study was designed to assess the relationship between antibodies against bovine viral diarrhea virus (BVDV) determined in the bulk tank milk (BTM) and the within-herd seroprevalence. We also assessed the efficiency of measuring antibody levels in BTM samples to monitor BVDV infection status in a herd. In the 81 farms included in the study, BTM samples were obtained and blood samples withdrawn from all cattle older than one year. The infection status was then determined in serum and milk using a commercial blocking ELISA based on the detection of anti-p80 antibodies. Apart from these baseline serum and milk samples, another BTM sample was collected from each herd 9 months later, and a third BTM sample obtained 9 months after this. In these second and third milk samples, anti-BVDV antibodies were determined using the same ELISA kit. Statistical tests revealed good agreement between herd seroprevalences (% seropositive animals in the herd) and the antibody levels detected in the BTM samples. During the 18 months of follow-up, the farms with persistently infected cattle at the study outset (14.8% of the herds) showed a significant decrease in BTM antibody titers after virus clearance. Conversely, a significant increase in BTM antibody levels was observed in the herds infected with BVDV during the follow-up period. Our findings indicate that monitoring antibody levels in the BTM is a useful method of identifying changes in the BVDV infection status of a herd.

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Bovine viral diarrhoea virus control in Finland 1998–2004

Cited by 26 publications

References 3 publications

Test Strategies in Bovine Viral Diarrhea Virus Control and Eradication Campaigns in Europe

Test Strategies in Bovine Viral Diarrhea Virus Control and Eradication Campaigns in Europe

BVD eradication in Switzerland—A new approach

Monitoring bovine viral diarrhea virus (BVDV) infection status in dairy herds

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