Schmallenberg: how to spot and report the disease

Sheeping lying in a field
Alan Robertson
Tuesday 14 January 2025 - 08:23

Updated guidance about Schmallenberg virus (SBV) has been published by Scottish Government to support farmers and crofters identify the illness in livestock.

(SBV) is a virus first identified in Europe in 2011. It was first detected in the UK in 2012, and then in 2016-2017 and from 2021 onwards. 

It is spread by biting midges, can infect sheep, cattle and goats and is notable for congenital malformations especially in lambs. Adult animals may show mild general signs if any at all. 

SBV is not notifiable in the UK, no restrictions are placed on premises where SBV is present and SBV is not known to be a risk to human health.

Individual herd or flock losses of neonates due to Schmallenberg vary but on average, in 2013 SBV affected flocks reported an extra 3% lamb mortality than those flocks not affected, which is relatively a low impact. However, some flocks experienced 50-60% losses due to SBV which is severe. 

The latest situation in the UK is that SBV has a low impact. England and Wales saw evidence of significant spread of Schmallenberg in 2023, with flock and herd infertility and the birth of deformed lambs and calves. Scotland has been largely unaffected until 2025, when new cases were confirmed by SRUC. However, Farmers and crofters should remain vigilant and discuss any concerns with their vet. Keepers are able to submit still-born calves and lambs to SRUC, where they will undertake SBV testing (PCR, foetal serology and histopathology) as appropriate, as part of the standard investigation work at no extra cost. 

The impact of the disease will be influenced by factors such as midge activity and the immunity status of herds and flocks.

Animals exposed to the disease seem to develop immunity, making it likely that disease will die out in areas where the disease has been present. However, immunity will fade with the turnover of livestock and disease can return. 

Full details at Schmallenberg: how to spot and report the disease - gov.scot

 (pic by A Robertson)