Positive antibodies for Schmallenberg virus (SBV) have been detected in some Irish dairy herds, according to a statement released by the National Disease Control Centre of the Department of Agriculture this week.

Testing undertaken by regional veterinary laboratories (RVLs) has confirmed the circulation of the virus, after the receipt of a number of reports of milk drop syndrome in dairy herds this summer.

A high rate of seropositivity or exposure to SBV was found in the samples brought in from some of these herds.

Where testing proved positive for SBV, some of the clinical signs included milk drop, diarrhoea, pyrexia (raised temperature) and apparent pregnancy loss, although not all clinical signs were present in all affected animals.

Signs

"Many of the seropositive animals had been born since 2018, which is when the virus is thought to have most recently circulated in Ireland. This indicates more recent re-emergence of the virus.

"Care must be taken in interpreting single serology results, as alone they are not diagnostic for SBV," the Department said.

However, the Department added that in some of these herds, the virus itself has been detected or very recent infection has been diagnosed using paired serology tests around the same time the clinical signs occurred, suggesting that SBV was responsible.

Farmers are advised to be vigilant for the clinical signs described and consult their veterinary practitioner for advice if they are seen.