Fears mount as Schmallenberg outbreak spreads further north

There are fears that the area affected by the Schmallenberg virus (SBV) has increased and spread further north in 2017, according to the Department of Agriculture, Food and the Marine.

A department spokesperson confirmed to AgriLand that the Regional Veterinary Laboratory (RVL) network has reported an increase in the number of suspected SBV cases in aborted lambs and calves submitted this past week.

The increase has been particularly prevalent in aborted lambs.

A number of suspect cases submitted this week, and at the end of last week, to Sligo and Athlone RVLs have birth deformities that are very suggestive of the effects of SBV infection of ewes during pregnancy.

Results of the polymerase chain reaction (PCR) test are currently being awaited from these submissions – which are suspected to have SBV.

But these submissions – from counties Sligo, Cavan and Leitrim – tend to confirm observations, made last autumn by RVLs, of animals showing antibodies to SBV in new areas north of the Dundalk-Galway line, the spokesperson for the department said.

It also supports the hypothesis that the SBV-affected area has now increased, and includes counties Cavan, Leitrim, Sligo and probably some neighbouring counties, the spokesperson added.

Up until now, all confirmed cases, and the vast majority of suspect cases, came from the southern part of the country. But this appears to have changed in 2017 – with strong circumstantial evidence of a spread of the virus to new areas in the north midlands and north-west.

“The department’s advice to Irish farmers on SBV remains essentially unchanged since its first incursion.

“SBV is a low-impact disease, with the potential to cause significant losses in individual herds/flocks. Particularly where a substantial number of susceptible animals are infected, for the first time, at a vulnerable stage of gestation – especially where breeding is synchronised,” the department spokesperson explained.

Response

The department continues to offer free post-mortem examinations and SBV screening for deformed ruminant foetuses/neonates where SBV is suspected.

This service is offered through its network of RVLs, with specialised supports and PCR testing provided by the General Virology Division Backweston.

As it is not a regulated or statutorily controlled disease entity, there is no active surveillance programme for SBV, the department spokesperson said.

Meanwhile, the department also explained that the PCR test is for viral genetic material (RNA) and needs to be interpreted with caution. The presence of viral DNA is not definitive proof of a causal link; a negative does not prove the absence of SBV viral involvement, the spokesperson concluded.

More information on the disease is available on the department’s website.

Figures from the department show that between the beginning of 2016, and the end of last year, there were 67 positive SBV cases confirmed.

A total of 35 of these positive cases were detected in bovine animals, after 1,025 samples had been tested. The remaining 32 cases originated in ovine animals, after 218 samples were tested.