Schmallenberg virus appears to have spread further north in Ireland in 2017 – Vet labs
Previously unaffected areas north of the Dundalk-Galway line could now be susceptible
A high number of suspected Schmallenberg Virus (SBV) cases in aborted lambs and calves were recorded by the Regional Veterinary Laboratories (RVL) network in the first week of this year.
A number of suspect cases particularly in lamb foetuses submitted to Sligo and Athlone RVLs have birth deformities that are very suggestive of the effects of SBV infection of ewes during pregnancy, according to an RVL report.
It says while the polymerase chain reaction (PCR) results for these submissions are still pending to date, they appear to confirm observations by RVLs last autumn of animals showing antibodies to SBV present in previously unaffected areas north of the Dundalk-Galway line (Sligo, Cavan, Leitrim and probably neighbouring counties).
Prior to this, all confirmed cases originated from the southern part of the country.
SBV infection causes only mild, unspecific clinical signs such as pyrexia, milk drop, anorexia, weight loss and diarrhoea in adults.
In pregnant animals, it can cause abortions from the early stages of pregnancy and a range of congenital deformities that primarily affect the central nervous and musculoskeletal system and may be variable in severity.
Deformities commonly include arthrogryposis, (bent limbs, fixed joints) kyphosis, scoliosis, torticollis (twisted neck, spine), brachygnathia (short jaw), hydraencephaly (domed skull), and cerebellar dysgenesis that may occur or ‘dummy’ calves if infected at certain times during pregnancy.
Congenital deformities may occur due to other toxic and viral conditions, however, SBV should be suspected if there are multiple incidences in the same herd within a short time window and if deformities are similar to those described above.