Survey reveals midge-borne virus activity in south-west

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Signs of the deadly Schmallenberg virus (SBV) have been identified in the south-west of Scotland.

A survey carried out by SAC Consulting Veterinary Services, in conjunction with Livestock Health Scotland, found that the midge-borne disease was circulating in Dumfries and Galloway in autumn 2017.

The survey, which is ongoing, involves monitoring bulk milk samples from 50 dairy herds across Scotland.

SBV, which first entered the UK in 2011, is capable of causing deformities in both calves and lambs.

Initial infection causes symptoms including reduced appetite, raised temperature, milk drop and scour. Cattle and sheep getting infected in the earlier stages of pregnancy often results in infection in the foetus and skeletal deformities in the lambs and calves when born.

George Caldow, who heads up SAC Consulting Veterinary Services, said foetal deformities caused by the disease were detected in southern Scotland and northern England last year.

Cases were seen in lambs from the middle of January until early May, suggesting a potential infection window of between the middle of September and the middle of December in 2016.

“Each farm acts only as sentinel to SBV virus activity in the local area and circumstances vary from farm to farm with regard to virus spread and midge activity,” said Mr Caldow.

“The results of the study so far can therefore only act as a guide, but do suggest that there has been some active transmission of the SBV virus in Dumfries and Galloway in the autumn of 2017.

“This could potentially lead to the birth of deformed lambs and calves. However, in other areas of the country, particularly north of the central belt, we expect the disease risk to be much lower. Farmers concerned about potential SBV risk should speak to their vets in the first instance.”

Livestock Health Scotland chairman and former NFU Scotland president Nigel Miller said the survey highlighted the value of targeted disease surveillance.

He said: “The positive bulk milk samples from the south-west not only provide an early warning of possible problems ahead, during the 2018 calving and lambing period, but also increase our understanding of the ability of the Schmallenberg virus and its vectors to persist and spread under Scottish climatic conditions.”

animal health