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Schmallenberg Virus - advice and opinion

"Vector research is even more important with SBV than it was with BTV8. We have to start from scratch with this one and I think that every biting insect could be a potential vector as the spread of the virus by "midge only" would have been more limited." German Cattle Breeder's email to

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Schmallenberg virus: "may cause severe congenital damage in pregnant animals, as well as premature births and reproductive disorders"
(More information below)       Updated May 2012 OIE technical factsheet - pdf

June 2012 ~ "origin is still not known and should be investigated as more information becomes available.....Currently, there is no evidence of any other route of transmission other than transplacental or vector borne routes."

June 2012 ~ AHVLA survey of sheep farmers

May 2012 ~ The OIE TECHNICAL FACTSHEET has been updated for May

May 2012 ~ Genetic reassortment between Sathuperi and Shamonda viruses of the genus Orthobunyavirus in nature: implications for their genetic relationship to Schmallenberg virus.

May 2012 ~ Letter: Culicoids as Vectors of Schmallenberg Virus

Technical Report "Schmallenberg" virus: analysis of the epidemiological data


The Central Veterinary Institute (CVI)in the Netherlands has developed a test for the demonstration of antibodies against SBV. (pdf)

Dr Ruth Watkins tells the BBC says it is 'inevitable' there will be cases in Wales and warns against culling infected animals since the animal will react to the virus with a "wonderful neutralising antibody immune response"

February 2012 ~ Schmallenberg virus: technical factsheet

SBV epidemiology

According to the epidemiological investigations, reinforced by what is already known about the genetically related Simbu serogroup viruses, SBV affects domestic ruminants. It is unlikely to be zoonotic. The spatial and temporal distribution suggests that the disease is first transmitted by insect vectors and then vertically in utero.

1. Hosts

a. Cattle, sheep, goats
b. Bison
c. No information on the susceptibly of exotic ruminants (camelids, llamas, etc), or other wild ruminants, or on other species. It is worth noting that other viruses of the Simbu serogroup affect wild ruminants and that antibodies to Akabane virus have been found in horses, donkeys, buffalo, deer, camels, and even in pigs. Some viruses of the Simbu serogroup (Mermet, Peaton, and Oropouche viruses) have also been detected in birds.
Mice and hamsters can be infected experimentally.
d. Humans: no human disease related to SBV has been reported in the affected zone so far, and the genetically most related Orthobunyaviruses do not cause disease in humans. Thus current risk assessments conclude that the virus is unlikely to cause disease in humans even if it cannot be fully excluded at this stage. Nevertheless, close collaboration between public health and animal health services is recommended for the early detection of potential human cases, particularly in farmers and veterinarians in close contact with potentially infected animals, and especially during interventions for dystocia.

2. Transmission

The transmission of SBV needs to be confirmed but hypotheses have been developed through recent epidemiological investigations and comparison with other Orthobunyaviruses:
a. It is likely to be transmitted via insect vectors (biting midges and/or mosquitoes)
b. Vertical transmission across placenta is proven
c. Direct contamination from animal to animal or animal to human is very unlikely but needs further investigation (1st experiments have been started).
Further research is still needed to confirm these transmission routes and to determine the competent insect species.

3. Viraemia and incubation period

Experimental infection in 3 calves showed mild clinical signs of acute infection at 3 to 5 days post-inoculation and viraemia at 2 to 5 days post-inoculation. No data are available for sheep and goats up to February 2012.

4. Sources of virus

- Source of transmission: likely to be infected insect vectors.
- Material found to be positive in virus isolation (up to February 2012): virus has been isolated from blood from affected adults and infected foetus and brain from infected foetus. [see comment below]
Material found PCR positive (up to February 2012): organs and blood of infected foetuses, placenta, amniotic fluid, meconium.
All these findings have to be further investigated for their role in transmission.

5. Occurrence

Only some Orthobunyaviruses had been reported in Europe, such as, Tahyna virus from the California serogroup, but viruses from the Simbu serogroup had never been isolated in Europe before.
1st phase: SBV was first detected in November 2011 in Germany from samples collected in summer/autumn 2011 from diseased (fever, reduced milk yield) dairy cattle. Similar clinical signs (including diarrhoea) were detected in dairy cows in the Netherlands where the presence of SBV was also confirmed in December 2011.
2nd phase: in early December 2011, congenital malformations were reported in newborn lambs in the Netherlands, and SBV was detected in and isolated from the brain tissue [see comment below]. Up to February 2012, Belgium, Germany, United Kingdom, and France have reported stillbirth and congenital malformations with PCR positive results. Read Update 18 at ProMed in full

February 11th 2012 ~ "It might look from this that Schmallenberg virus is definitely here to stay and spread through out Northern Europe. One cannot say without the detailed entomology of virus infection..."

February 11th 2012 ~ Video: Professor Peter Mertens, head of vector-borne diseases at the Institute for Animal Health

February 10th 2012 ~ Reactions of the virologist, Ruth Watkins, after the online discussions

February 10th 2012 ~ Farmers Guardian have their Schmallenberg web discussion today 1pm.

February 10th 2012 ~ Some of the main points made on the FWi live forum last night

advice and information

These pages are updating very frequently. Please refresh the page

OIE's weekly disease information, which includes SBV, can be found here

Farmers Guardian Schmallenberg: The Facts Jan 26th 2012

EPIZONE will organize a Satellite symposium on the topic "Schmallenberg virus" after the 6th Annual Meeting EPIZONE in Brighton on 15th June 2012 Keynote speakers will be invited for lectures on all aspects of the Schmallenberg virus, such as diagnostics, vaccine development, epidemiology, and risk assessment. More Brighton.

December 2011 Risk Assessment pdf. Potential implications for Human Health (European Centre for Disease Prevention and Control)