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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 warmwell.com
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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."
Schmallenberg virus: Analysis of the Epidemiological Data and
Assessment of Impact ~ EFSA Journal 2012;10(6):2768 [89 pp.]
"It is recommended that serological investigations are continued both
in affected regions and regions neighbouring the known affected areas
in order to determine the geographic spread of SBV infection and
estimate seroprevalence. Such information would be useful to reduce
under-ascertainment and improve modelling predictions.
No data is available regarding within-herd impact. Information
concerning the number of newborns and foetuses within a holding with
arthrogryposis hydranencephaly syndrome (AHS) type clinical signs and
other consequences of SBV infection such as loss of production is
needed. This could be achieved by follow-up monitoring of selected
herds to properly evaluate the impact and magnitude of the spread of
Continued monitoring of EU ruminant adult population in affected
regions and regions neighbouring the known affected areas is necessary
in order to early detect infection with SBV. Monitoring of the
putative vector populations (distribution, abundance and SBV
detection) should be continued...."
June 2012 ~ AHVLA survey of sheep farmers
BVA is asking members to encourage clients to respond to a survey measuring the impact of SBV on sheep farms during the 2011/12 lambing season. The survey will help AHVLA better understand how SBV has affected animal health and welfare in GB. See BVA website
AHVLA is asking all sheep farmers, including those who did not have Schmallenberg in their flock/s, to answer a short online questionnaire. There are 30 questions, which should take less than 30 minutes to complete. Links to English and Welsh versions of the questionnaire can be found below:
A summary of the survey results will be published on the AHVLA website, but no individual farms will be identifiable from these results. The closing date for answering the online questionnaire is 15 July 2012. Any questions about the survey should be sent to SBVsurvey@ahvla.gsi.gov.uk.
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.
Arch Virol. 2012 May 16.
Yanase T, Kato T, Aizawa M, Shuto Y, Shirafuji H, Yamakawa M, Tsuda T.
Kyushu Research Station, National Institute of Animal Health, NARO, 2702, Chuzan, Kagoshima, 891-0105, Japan, firstname.lastname@example.org.
Abstract(Thanks for the link from http://www.flutrackers.com/forum/showthread.php?p=454488 )
The recent outbreak of malformations in ruminants in Northern Europe caused by Schmallenberg virus induced us to analyze the genetic properties of the related orthobunyaviruses and clarify their relationship.
The sequencing of three genomic RNA segments of Sathuperi, Shamonda and Douglas viruses (SATV, SHAV and DOUV) revealed that the M RNA segment of SATV and DOUV had a high degree of sequence identity with that of Schmallenberg virus, but the S and L RNA segments closely matched those of SHAV.
Phylogenetic analysis of the three genomic RNA segments indicated that Schmallenberg virus is a reassortant, with the M RNA segment from SATV and the S and L RNA segments from SHAV
May 2012 ~ Letter: Culicoids as Vectors of Schmallenberg Virus
From ProMed Posting
Read ProMed posting in full
We present evidence that culicoids captured in October 2011 in Denmark contained SBV RNA and most likely are vectors for this agent.
In autumn 2011, culicoids were collected from several sites within Denmark. One site, a chicken farm in Hokkerup [for map, refer to the original article at the source URL] was selected for study because of its location close (6 km) to the German border and proximity (less than 10 km) to an SBV-infected sheep farm in Germany, as reported on 9 Mar 2012 by the Friedrich Loeffler Institute surveillance website (http://www.fli.bund.de).
The culicoids were collected during 14-16 Oct 2011. Midges were sorted manually into 91 specimens of the _C. obsoletus_ group (comprising _C. obsoletus_, _C. chiopterus_, _C. dewulfi_, and _C. scoticus_) and 17 of the _C. punctatus sensu stricto_ group, then stored at -20 C.
Two of 22 pools tested strongly positive for the large (L) and small (S) segments of SBV RNA. Each positive sample was derived from 5 midges of the _C. obsoletus_ group. One pool produced cycle threshold (Ct) values of 26.4 and 24.5 (in the L segment- and S segment-specific assays, respectively), whereas the 2nd positive pool gave Ct values of 28.8 (L segment) and 27.6 (S segment).
These pools were negative for the internal endogenous control that targeted the bovine/ovine beta-actin mRNA. This result makes it unlikely that the detection of SBV RNA within the midges resulted from recent blood meals from infected animals remaining within the culicoids and suggests the virus has replicated within the midges.
Even if all 5 culicoids in a pool had recently taken a blood meal from a viremic animal, the Ct values observed here strongly suggest replication of SBV within the _C. obsoletus_ group midges. However, in principle, other hosts of SBV could have a much higher level of viremia than cattle and could provide the levels of SBV RNA detected. _C. punctatus_ s.s. midges cannot be ruled out as a possible vector of SBV because of the limited number of insects tested.
Our study demonstrates the presence of SBV RNA in _C. obsoletus_ group midges caught in Denmark during October 2011. The low Ct values (i.e., high SBV RNA levels) and the absence of ruminant beta-actin mRNA in these samples strongly suggest that SBV replicates in these midges and, hence, that the _C. obsoletus_ group midges are natural vectors for this virus.
[Byline: L. Dam Rasmussen, B. Kristensen, C. Kirkeby, T. Bruun Rasmussen, G.J. Belsham, R. Bodker, and A. Botner]
Technical Report "Schmallenberg" virus: analysis of the epidemiological data
European Food Safety Authority's second report on the Schmallenberg virus (SBV). It can also be downloaded here.
The report shows that
"when based on worst case scenario assumptions, the number of infected ruminants is low compared to the total number of these animals in each Member State.
The results of EFSA’s report were shared at a scientific seminar held in Brussels organised by the European Commission’s Health and Consumers Directorate General (DG SANCO) that aims to present the current state of play on the latest scientific information on SBV and the risk management approach taken by the EU.
...The data collected by Member States have allowed the Authority to analyse the current geographical distribution and impact of the disease in the European Union.
Some caution nevertheless should be exerted when interpreting the data as underreporting or lack of diagnostic confirmation may affect the picture.... EFSA will assess the overall impact of the SBV infection on animal health, animal production and animal welfare together with a characterisation of the pathogen by 31 May 2012."
The Central Veterinary Institute (CVI)in the Netherlands has developed a test for the demonstration of antibodies against SBV.
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"
From the BBC Wales website (Extract)
".....Dr Ruth Watkins warns against culling infected animals as they will become immune.
Some farms in Wales have been tested after more than 80 cases were reported in England....
"Wales may get away with either none or very few infections this year because the extent of spread in the UK seems to be associated with these plumes of midges and mosquitoes that have come over from Europe. It is worrying what will happen next year if the virus reappears here in Britain. I think if the virus reappears in Britain, I think it will be inevitable [that Wales will see cases] next year yes.
She suggested adopting the same process as the Bluetongue disease which is to grow it up in culture, inactivate the virus and make an inactivated virus vaccine.
This seems to be a very competent virus and it's caused this huge outbreak already even though it was only detected for the first time last year...
Dr Watkins described the virus as a "nightmare" for farmers dealing with the Schmallenberg virus as there is no vaccine available.
But she insists culling is not the answer.
"If you are unfortunate to have it this year, keep those animals for next year because the harm comes when the insect bites an animal and they have a primary virus infection and that's what can get passed to a.. foetus. But after that, they make this wonderful neutralising antibody immune response to viruses and it does protect them against such an event again. So that's why you should keep an infected animal.
Read in full
February 2012 ~ Schmallenberg virus: technical factsheet
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.
a. Cattle, sheep, goats
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.
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.
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..."
Readers with some scientific knowledge will be interested by the critique written by Dr Ruth Watkins, on the recent EFSA document. It concludes:
"....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 - which is mentioned but not greatly enough emphasised in the EFSA document. I think this needs to be well funded by the EU. It seems to me to be greatly lacking." Read Dr Watkins' critique and the post below about the EFSA document when it appeared.
February 11th 2012 ~ Video: Professor Peter Mertens, head of vector-borne diseases at the Institute for Animal Health
Prof Mertens tells Farmers Weekly about the work being done to tackle the Schmallenberg virus. "We don't know what's going to happen. We don't know what's going to happen next year."
IAH can detect the virus but the problem is the virus has a short viraemic period. Detecting virus outside this period means needing to be able to detect antibodies. Watch the short video at www.fwi.co.uk
February 10th 2012 ~ Reactions of the virologist, Ruth Watkins, after the online discussions
Dr Ruth Watkins, formerly Head of Diagnostic Virology at St Mary's Hospital where she was an Honorary Consultant and Senior Lecturer in the Department of Virology at St Mary's Hospital Medical School, Imperial College School of Medicine, London, is currently a sheep farmer in Wales. With her expertise in virology and first hand knowledge of farming, her views are very valuable. Her summary of points:
As usual, we are very grateful to Dr Watkins.
- All those farms on which there has been an outbreak should keep those ewes to breed next year. From experience with Akabane and the use of vaccines it is clear that immunity from the acute and short lasting infection in the adult ewe is strong and likely to provide protection against reinfection. I am not sure if sufficient ewe lambs from this summer will also have been infected on these farms but this may well be so. So these ewe lambs as yearlings put to the ram next year if infected in 2011 or early in the summer of 2012 should not have affected lambs as they will be protected against having the infection whilst pregnant.
- The concept of the susceptible period of the foetus during which a primary infection of the mother ewe will cause death or deformities was not mentioned. It should be. The farmer with her question about lambing ewes in May should have no cause for concern. Even if infected in May there should not be a problem with her lambs. (There is a possibility of meningo-encaphalitis in calves and cattle but we don't know if this will occur with Schmallenberg virus and it only seems to occur with certain strains of the Shamondo viruses, and no comment can be made on this yet. I don't think there is a need to mention it).
- It is clear that lambing in April May would be advisable next year. May would be preferable. It was very mild this year and I am not sure when midges were no longer active but they could certainly have been through November at least. I believe that Pirbirght should be able to answer this. This would mean putting rams in at the start of December. This is such an important point that I am surprised the BVA man has not grasped it. I put my rams in in November but I am going to wait until December next year if the Schmallenberg virus is shown to be active next summer in the UK.
- The best date for cattle pregnancies is going to be a problem. The period of susceptibility of calves in utero is longer than for sheep. Also dairying and so on require Spring and Autumn calving. Probably Autumn calving will be safer than Spring calving.
- There should have been absolute clarity in the answer that no product has been shown to repel midges sufficiently to prevent biting and infection. Again the BVA vet should have been absolutely clear on this- he was corrected by the Belgian farmer. (Where was he during the BTV8 outbreak?)
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
The conversation can still be seen on www.fwi.co.uk/livestock/schmallenberg-virus/schmallenberg-QandA/ advice and information
Read entire conversation on www.fwi.co.uk/livestock/schmallenberg-virus/schmallenberg-QandA/
- Notifiable disease?Ian Davies, head of AHVLA's small ruminants experts group and president of the Sheep Veterinary Society, said there were no plans to make the disease notifiable at present.
- How many in the flock affected A sheep farmer reported that around 12% of his ewes were affected. "This does not include ewes that appear to be 'missing' lambs, ie, triplets having singletons."
- Culicoides survival Peter Jones at the BVA hoped that midge' survival will be curtailed by "h this very cold spread that we are having now"
- No slaughter policy Ian Davies - AHVLA explained that there isn't a slaughter policy for Schmallenberg. (There would be no point even if it were an ethical course of action since infected animals do not themselves infect other animals.)
- livestock movement controls Johann Tasker reported that DEFRA had said it would be unlikely to impose them "On the basis that the cost to the industry would outweigh the benefits, and that there is no vector (midge) activity at present." Peter Jones BVA said movement controls including imports are not going to help because the virus is already present in the UK insect and animal population so the disruption to trade might outweigh the benefits
- Immunity and Infectivity
Peter Jones BVA
said that once immunity is in place it is very strong and the animals once recovered
are not infectious. "Whether it's lifelong is too early to tell. this is something we have to find out about this new virus."
The Belgian farmer reported that at an official meeting on Wednesday in Brussels a Belgian government vet claimed that "they expect sheep to build up immunity to the disease so that SBV can be solved within a couple of years"
- Cattle Peter Jones BVA predicted that when cows that" became pregnant last Autumn begin to calve down in the Spring we anticipate seeing cases of malformed calves as well"
- Deformed lambs - viability The sheep farmer had found that some of the less deformed lambs could be saved and "are thriving" - "provided they are able to stand and suckle they are absolutely fine." He has had a few with "rather wonky legs and deformed jaws but if they can suckle we give them a chance". Some lambs are born blind and obviously brain damaged. "We have had no cause to cull infected ewes as they are healthy and milking well, they do not appear at all unwell."
- Under reporting Peter Jones BVA said that under-reporting is an issue "especially in the early cases where reporting to the World Animal Health Org required locations of affected farms to be identified so farmers were understandably put off reporting . I believe that has now been sorted."
Falko Steinbach,Virology Dept AHVLA, confirmed that the data submitted to OIE do not contain the locations of farms.
- PCR Tests Falko Steinbach said that the AHVLA were working closely with colleagues at Friedrich Loeffel Institute "who have developed the first and now second generation of PCR tests. These are molecular tests detecting traces of the virus. These tests have been established here and at SAC/Moredun in Scotland. "
- Vaccine Peter Jones BVA added that " there is good progress in work having started on vaccine development although it will take about 18 months but this is fast compared to conventional development times." Peter Jones BVA said " we know immunity is very strong and that with effective vaccines does mean we should have a good chance of effective control."
- Cost of tests Falko Steinbach said that at present "we can offer the tests for free, which means that Defra is picking up the costs..we are encouraging farmers to inform our AHVLA offices across the country if they have suspicious cases. .. it might be that we will have to charge at some stage, but this is not my or our decision here in the lab." The sheep farmer said "I suspect that many farmers would not bother even reporting it" if they were charged for tests.
- Protecting animals Peter Jones said it is very difficult until there is a vaccine "because the virus is present in the insect population so the only way would be protection form biting midges - a very big ask really"
- Source Falko Steinbach said that imports were all across the county but since all cases we so far are in the very East of England it seems unlikely that import of animals has played any role. Ian Davies -AHVLA said that some cattle have been imported from infected areas, but "because it is thought that the infectious period for cattle is short, the risk of introducing disease by this method is low".
Ignace, the Belgian farmer, (article) said there is no problem with importing animals now... there is NO circulation of virus at this moment
- Clinical signs Falko Steinbach said clinical signs in adult sheep and cattle are generally mild and were thus often overlooked. "Most, if not to say almost all adult sheep will recover from infection2
- Serological Test Falko Steinbach:"A blood test is available now to see if sheep/cattle are infected. However, outside the midge season this is not reasonable to apply. What we are working on now is a serological test to detect a previous infection. This will take a few weeks and at first work best at herd level, not for individual animals."
- Insecticides/repellents Peter Jones BVA " I was just looking at all the products listed for control of external parasites and there are many but all for ticks and flies but none for Culicoides species...We need to look some more at this. The Belgian farmer, Ignace, said BT8 has shown that using products against midges etc. isn't 100% effective not even 50%
- Spread from infected animals?Falko Steinbach said " we have no indication of a persistent infection in ewes. Ewes infected before have cleared the virus and are immune not able to spread the disease further"
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
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
December 2011 Risk Assessment pdf. Potential implications for Human Health (European Centre for Disease Prevention and Control)