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In at the deep end

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NEWS that Schmallenberg virus (SBV) is still circulating in Great Britain may not be surprising but is worrying nonetheless. The question is, what happens next? As a new disease, SBV presents challenges in itself. Having arrived at a time when Defra's budget is reducing and the department and the livestock industry are having to devise ways of sharing responsibilities for animal health, it also presents challenges for the new ways of working, which, while still evolving, are now being put to the test.

Steps being taken by the Government in relation to SBV were outlined in a recent letter to Veterinary Record from the deputy chief veterinary officer, Alick Simmons (VR, August 4, 2012, vol 171, p 130). Following enhanced surveillance for the virus earlier this year, these include: six-month studies on the pathogenesis of the virus by the AHVLA and vector studies at the Institute for Animal Health (IAH); collaborative studies with other EU member states under a research programme funded by the European Commission; and an online questionnaire survey of sheep farmers, responses to which are still being analysed. In addition, Defra will be carrying out surveillance in counties in England and Wales in which the virus has not yet been found, by testing a number of samples currently being taken from sheep as part of the annual Brucella testing programme, as well as by testing certain acute clinical cases in cattle.

In his letter, Mr Simmons pointed out that SBV is a ‘non-notifiable, low-impact disease for which there are no appropriate control measures’ and that, in responding to new and emerging threats, ‘government needs to take a measured response, considering the cost-benefits of any actions and the impact of the disease, and align these with its other priorities for resource and funding’. This, in nutshell, is what lies at the heart of the discussions about responsibility and cost sharing, which have been going on for some years now and, judging from all the noises emanating from government, seem set to provide the model for approaches to disease control efforts in the future.

He also pointed out that, by working collaboratively and taking the actions it had done, Defra was ‘helping address the unknowns about SBV and making available to industry what is currently known’. No-one can fault Defra, the AHVLA and research institutes such as the IAH and others further afield in making information about SBV available, and in doing so quickly. The question, and one which might equally apply to other diseases in the future, is what is the industry going to do with it?

This question is particularly apposite in the case of SBV because, despite a fair amount having been learnt in a relatively short time, there is still much that is not known and, although work on a vaccine is progressing, this is unlikely to be available soon. This midgeborne virus may be considered to be of low impact at European and national level, but it is undoubtedly distressing to farmers whose animals are affected. News that the virus is still circulating will be of particular concern in areas that were previously unaffected, where animals will not have immunity and farmers face the prospect of losing lambs and calves. If SBV behaves like Akabane virus, to which it is related, it could, given the right circumstances, spread rapidly among sheep that have not been exposed to it previously. Meanwhile, experience in northern Europe suggests that, if it infects sheep during a critical period of gestation, this can lead to fetal abnormalities. Potentially, therefore, farmers in the previously unaffected areas in northern England, Scotland and Wales who decide to tup their ewes in late summer might be putting them at risk of infection at a dangerous time. Although studies so far have indicated that there is a good level of immunity in previously infected animals, the degree of protection is still not known, so there will be a need to remain vigilant for new cases in previously affected areas.

All this serves to emphasise the continuing importance of surveillance, monitoring and reporting of cases, as well as for research into animal diseases. It also underlines the need to make information widely available, so farmers can make informed decisions about managing their animals. This may be the approach to be adopted in the future, and plans for new ways of working had to be tested at some stage, but the uncertainties and complexities of SBV mean that it may not have been the easiest example with which to start.

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