November 26, 2012

European Food Safety Authority gives update on EU's Schmallenberg virus

A report analysing the latest epidemiological data available on the incidence of the 'Schmallenberg' virus in Europe was published by the European Food Safety Authority (EFSA).

The report outlines that by the end of October 2012, the virus, affecting domestic and wild ruminants, was reported by 14 countries. The most recent data reported in this latest publication show that 'Schmallenberg' virus (SBV) has continued to circulate within Europe with newly affected herds being identified in new regions by October 2012. Approximately 6,000 holdings have had the presence of SBV confirmed by laboratory tests.

EFSA reiterates that the number of affected herds is low compared to the total number of herds with a maximum proportion of confirmed SBV herds per region being 6.6% for sheep and 4% for cattle. The Authority does not have data at this time to assess the impact on affected herds.

In August 2012, 294 herds were reported with AHS symptoms in cattle. In September and October the number of herds with AHS symptoms decreased however acute cases in adults (adult animals where clinical signs were observed and SBV diagnosis confirmed) were reported in August, September and October. It is important to note that the number of countries reporting acute adult cases is limited and it is likely that adult cases are not diagnosed considering the transitory and non-specific nature of the clinical signs observed. An increase of the number of AHS cases is likely to occur in the coming months resulting of infection of previously unexposed animals in the susceptible period of gestation.

At the time of publication of the last EFSA epidemiological update in May 8 member states (Belgium, France, Germany, Italy, Luxembourg, the Netherlands, Spain and UK) had reported confirmed cases of SBV. During the summer SBV confirmed cases were reported in new countries; including Denmark, Finland, Poland, Sweden and Switzerland, and in new regions in France, UK and Germany. Other epidemiology reporting services indicate that SBV has also been detected in Austria and Ireland. SBV is continuing to spread to new areas of Europe, and it is likely that new SBV cases will be observed in Southern and Eastern regions of Europe in 2013.

The data available only allows a between herd impact assessment based upon the comparison between SBV confirmed herds and the total number of herds in each affected region by species. For all affected countries, the number of SBV confirmed herds is low compared with the total number of herds. The maximum proportion of confirmed sheep herds per region is 6.6% and 4% for cattle herds. Nevertheless, these comparisons should be interpreted cautiously since under reporting or lack of confirmation may affect the ratio. No information is available to assess within herd impact.