Schmallenberg Virus (SBV)
- What is Schmallenberg virus?
Schmallenberg virus (SBV) is a newly discovered infection of sheep, cattle and goats. It was first detected in Germany and the Netherlands but has since been found in many other European countries, and has spread across England and Wales. Recently cases have also been reported in Dumfriesshire and Aberdeenshire in Scotland.
The Freidrich Loeffler Research Institute in Germany first confirmed this was a new virus, and called it Schmallenberg virus after the area where it was first found. Although there is still a lot to learn about this new virus, it is closely related to other viruses, notably Akabane virus, which is also transmitted by biting insects and causes fetal deformity. SBV is also related to two similar viruses in the same family (the orthobunyaviruses) called Aino virus and Shamonda virus. For all these viruses, adult animals do not usually show any symptoms of infection and it is only when a deformed lamb, calf or kid is born that the disease is suspected.
- What diseases does Schmallenberg virus cause?
Original reports of disease were of fever and milk drop in adult dairy cows in the summer of 2011. However, in pregnant animals the virus can also infect the developing fetus (calf, lamb or kid), attacking the brain and spinal cord, causing damage to these organs and deformity of the legs, spine and head. Deformed calves and lambs were born late in 2011 and into 2012. Most of the time, similar viruses do not cause disease in non-pregnant animals (see below), so Schmallenberg virus may be slightly different; careful surveillance will be needed in affected areas to determine how important this is.
- How is Schmallenberg virus spread?
Schmallenberg virus is almost certainly spread by infected insects, most likely to be midges in the Culicoides family.
- How did Schmallenberg virus get into the UK?
Analysis of weather records suggest that the virus probably spread to South and East England when infected midges from continental Europe were carried over the channel in the second half of 2011, by a favourable wind direction, and fed on domestic livestock.
- How can you detect Schmallenberg in animals?
A specific PCR test to detect the virus in deformed fetuses is available and Moredun is screening all suspect Schmallenberg cases in Scotland using this test. A serology test is also available to screen for antibody to the virus in blood samples which will identify animals that may have had a previous infection. Defra will continue to pay for SBV testing in areas where the disease has not been reported before.
- Can the infection be transmitted from animal to animal?
We don't think so, as other viruses closely related to Schmallenberg virus need the midge/mosquito to transmit infection. More research is being performed to find out more about Schmallenberg virus, how it is maintained within the vector and how it spreads.
- How big a problem is it in the UK?
In 2012 there were 220 confirmed premises with affected sheep, 3 premises with affected cattle and sheep and 53 premises with only cattle affected. AHVLA will soon be publishing the results of a survey of sheep farmers they conducted which will provide more information about the impact of this disease.
- Is there a vaccine available?
MSD Animal Health have been granted a Provisional Marketing Authorisation for the first vaccine against Schmallenberg, Bovilis® SBV.
- Is there a risk to human health?
Studies have determined that there is no evidence of infection of humans in close contact with infected animals and no illness has been reported to date in humans. It is therefore unlikely that Schmallenberg virus infects people but at risk groups (pregnant women, immunosuppressed people) should be advised to take suitable precautions if disease is suspected in the flock/herd.
What should farmers be doing?
Farmers are encouraged to look for and report any signs of disease such as milk drop, diarrhoea, fever and inappetance in adult animals, as well as signs of congenital deformities in newborn animals, to their vet.
|Post Movement Testing for Schmallenberg Virus - Guidance.pdf||40.82 KB|
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