A more detailed knowledge of midges' behaviour could lead to the development of accurate modelling and provide better protection against the spread of certain livestock diseases.

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Research by scientists from the Centre for Ecology and Hydrology, working with others from the Pirbright Institute, the Met Office and the Institute for Animal Health, demonstrates how a better understanding of midge activity can be used to reduce disease risk from viruses in sheep and cattle. At times when there is a risk of midge-borne disease – such as Schmallenberg Virus, which was discovered in 2011 and caused widespread consternation in Europe – farmers must ensure cattle movements are conducted when the risk of transmission is low, the researchers said.

Midges are inactive over winter, but the length of the inactive period varies in different regions and between different species of midge. The researchers believe they may be able to predict in advance how different environmental conditions will affect midges' activity, and organise livestock movements accordingly, which will reduce the risk of transmitting disease.

The researchers warned that current EU disease surveillance policy has a weakness in that it treats all midge species as one group, whereas looking at individual species allows for more accurate predictive models to be developed.

In addition to the Schmallenberg virus, the CEH experts said that five different strains of bluetongue virus (BTV), which is also transmitted by midges, have entered Europe since 2006.

Lead author Dr Kate Searle from the Centre for Ecology & Hydrology (CEH) commented, "At present the effectiveness of the movement restrictions is limited because they are applied collectively to a group of midge species (comprising the subgenus Avaritia) with no accommodation for seasonal differences in the activity of individual midge species, or their relationship with environmental conditions.

"We found that the length of the period for which midges were absent as adults over winter varied substantially between species by up to eight weeks, but also differed between years. These differences seem to be caused by subtle changes in climate as well as differences in the local availability of livestock and land use types such as pasture."

More information is available from Centre for Ecology and Hydrology here.