One case in Tipperary involved a calf, while there were two outbreaks in sheep in Co. Wexford. SBV, which is carried by wind-borne infected midges, was first detected in Ireland in 2012. In Ireland, as with other affected countries, the impact of the disease was short-term, after immunity built up in cattle and sheep (through exposure and vaccination), according to the DAFM. Since then, there has been a small number of outbreaks; this has been a low-impact disease overall, except on a small number of farms. On these farms, animals were infected at the stage of pregnancy when the foetus in utero is most susceptible to the effects of the virus, this unfortunately resulted in the birth of deformed off-spring.
While Schmallenberg continues to be regarded as a low-impact virus, the RVLs are emphasising the value of ensuring that deformed calves and lambs are submitted to them for testing, to increase the intensity and sensitivity of surveillance for both Schmallenberg virus and the potentially more impactful bluetongue virus (BTV). Both viruses can result in the birth of deformed offspring. Bluetongue has been detected in the UK and in Europe in the past year. Bluetongue can cause wide spectrum of clinical presentations, and it would risk causing significant animal welfare impacts as well as trade challenges if it became established here.
Both viruses can cause a wide variety of birth deformities, especially deformed limbs (arthrogryposis), spinal curvature (scoliosis), torticollis (twisted neck), shortened lower jaw (brachygnathia inferior), and domed skulls (hydranencephaly).
Some of these birth deformities can make natural calving or lambing very difficult and farmers should be alert to an increased risk of these ill effects in this season.
Bluetongue virus could come to Ireland through the wind-borne spread of infected midges, through the importation of infected animals or contaminated fomites or animal derived biological material (e.g. blood, semen).
Farmers are advised to be vigilant and to ask their vet to refer any birth deformities in sheep or cattle to the nearest RVL for investigation.