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Schmallenberg virus and surveillance

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THE emergence of Schmallenberg virus can certainly not be described as welcome. Nevertheless, it is both salutary and timely, as it comes at a time when arrangements for surveillance in England and Wales are under review (VR, January 14, 2012, vol 170, p 34). It is precisely this kind of emerging disease threat that scanning surveillance aims to detect – and it is also this kind of disease threat that might not be detected promptly if, for whatever reason, arrangements for surveillance fall short of the mark. With funding for surveillance in England and Wales set to reduce, the emergence and detection of Schmallenberg virus provides an important reminder of why surveillance is so vital.

The new virus provides a reminder, too, that surveillance is not just a local issue, and that robust networks are also needed nationally and internationally, with international cooperation playing a crucial role. Suspicions were raised in Germany and the Netherlands between October and November last year, with reports of signs in cattle including fever, reduced milk yield, inappetence, loss of condition and diarrhoea. In November, after ruling out other pathogens, scientists in Germany isolated and sequenced viral genetic material from clinically ill cattle and identified the new virus. Since then, there have been reports of deformities in newborn ruminants (mostly sheep, but also cattle and goats) in Germany, the Netherlands, Belgium and, most recently, the UK, where, on January 23, the AHVLA reported that the virus had been detected in samples from sheep with clinical signs consistent with Schmallenberg virus infection on four farms in Norfolk, Suffolk and East Sussex. The virus is thought likely to be transmitted by insect vectors and the affected farms in the UK were all in counties that had been identified as having been at risk from infected midges blown across the English Channel from affected areas on the Continent.

It is still too early to say how the outbreak will progress, but, as the lambing season gets underway, it is all too possible that more cases will emerge. On January 31, the AHVLA reported that the presence of the virus had been identified on a further seven farms in England, bringing the total to 11; as well as farms in Norfolk, Suffolk and East Sussex, it had been found in Essex and Kent.

Although the disease is not notifiable, vets who are aware of suspicious signs on their clients' farms are being encouraged to report them to the AHVLA in England and Wales, the SAC in Scotland and DARD in Northern Ireland, which are keen to investigate potential cases. That they are in a position to do so is due in no small part to collaboration with colleagues elsewhere in Europe with, for example, the Friedrich Loeffler Institute in Germany having made protocols and virus material available for use by other EU member states to help advance knowledge of this new disease. This kind of cooperation is commendable and highlights the importance of collaboration between investigating laboratories and the need for surveillance and other efforts to combat disease to be firmly underpinned by research.

Schmallenberg virus is not the first new disease to be detected by scanning surveillance, nor will it be the last. It was scanning surveillance that identified the emergence of BSE in the late 1980s and, in more recent years, it has been responsible for, among other things, the early detection of pandemic H1N1 influenza in pigs, four notifiable avian disease outbreaks, bovine TB in non-bovine species, antimicrobial resistance in Salmonella and virulent psoroptic mange in cattle. The AHVLA has noted that the value of its surveillance programme has greatly exceeded the cost in recent years, with monetised benefits having been estimated at over £200 million a year (VR, January 14, 2012, vol 170, p 34).

The review being undertaken in England and Wales aims to find ways of carrying out surveillance more effectively and at lower cost to the taxpayer. With spending on the scanning surveillance programme being cut from £10 million in 2009/10 to £6 million by 2014, this is not just a theoretical exercise. Ultimately, the shape of surveillance in England and Wales will be determined by the outcome of the debate on partnership working and responsibility and cost sharing. Progress in this debate has so far been slow but, as far as surveillance is concerned, the need for a solution is pressing. One of the problems with surveillance is that, very often, you are trying to find something you don't know is there until you've looked for it. It can be hard to persuade people to make the necessary investment in this and there must be concern about whether the mechanisms devised for responsibility and cost sharing will ever be able to make up for the imminent shortfall in funding.

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