Global knowledge gaps in the prevention and control of bovine viral diarrhoea ( BVD ) virus

Abstract

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.

Epidemiological factors and mitigation measures influencing production losses in cattle due to bovine viral diarrhoea virus infection: A meta‐analysis

“…In contrast to vaccination, biosecurity reduces BVDV production losses more effectively (Table ). This may be related to the fact that farmers often fail to apply the vaccine correctly, vaccines are not proven to be fully protective (Evans et al, ), e.g., in the prevention of in‐utero transmission of the virus (Moennig & Brownlie, ), the BVDV vaccine does not provide life‐long immunity and hence periodic vaccination is required (Weldegebriel, Gunn, & Stott, ), live BVDV vaccine could be contaminated with other viruses (Lindberg, ), and/or a critical vaccination coverage rate should be reached to prevent new PI animals (Scharnböck et al, ). In the present multivariate‐regression, testing and culling was not identified as a significant factor in changing the mean annual production losses per animal due to BVDV infection.…”

“…Large epidemiological studies and detailed documentation of production data are rare. Richter et al, () demonstrated that production losses vary considerably in the literature due to uncertainty and knowledge gaps regarding the epidemiology of BVDV infections (Evans et al, ). Although different epidemiology and mitigation situations were taken into account, the estimated mean annual production losses per animal in this work can only give rough indications of the true annual economic impact of BVDV on production due to the uncertainty of how representative individual studies actually are for the whole cattle population.…”

“…Depending on the time and duration of infection, BVDV can cause a considerable number of direct losses, such as morbidity and mortality due to immunosuppression, reduced reproductive performance (e.g., first service conception, extended calving intervals), stillbirth and abortion, congenital deformities and malformations, growth retardation, reduced milk production and average daily weight gain (Burgstaller et al, ; Houe, ; Marschik et al, ; Richter et al, ). Mitigation measures may comprise (a) preventing BVDV transmission by control of cattle trade such as testing of cattle before movements and/or reduced replacement rate of cattle possibly carrying persistently infected (PI) foetuses (Houe, Lindberg, & Moennig, ), (b) application of a vaccine, (c) biosecurity strategies such as cleaning of equipment, protective clothing, double fencing and (d) general prevention of contact with potential PI animals (Evans et al, ) as well as (e) testing and culling to eradicate BVDV. The economic impacts of BVDV for cattle farms have prompted many countries to implement mitigation programmes and the success of these programmes on the reduction of BVDV prevalences in the global cattle population has been reported elsewhere (Scharnböck et al, ).…”

A survey of biosecurity measures and serological status for bovine viral diarrhoea virus and bovine herpesvirus 1 on dairy cattle farms in north‐west and north‐east Spain

“…32 Therefore, farmers need to be motivated both to change existing behaviours and to implement effective biosecurity practices to reduce the risk of disease introduction. [33][34][35] MCA and TSCA show that there are three main farm typologies in relation to the implementation of biosecurity measures differentiated mainly by region (which implies different implementation of BVDV and BoHV-1 control programmes) and herd size. Although some biosecurity limitations were common, others were more specific to each cluster, similar to the observation made by Sarrazin and others.…”

Veterinarians’ Knowledge, Attitudes and Practices Associated with Bovine Viral Diarrhoea Virus Control and Prevention in South-East Australia

“…Biosecurity is defined as actions that are implemented to prevent pathogens from entering a herd and minimise the spread of pathogens within a herd [18][19][20]. Increased herd immunity can be achieved by vaccination or exposure of naïve cattle to PI cattle (often termed "deliberate exposure" when used as a control method) [21][22][23]. Pestigard ® , an inactivated vaccine, is the only commercially available vaccine within Australia [24].…”