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Published Date: 2012-02-11 00:03:45
Subject: PRO/AH/EDR> Schmallenberg virus - Europe (16): update, OIE
Archive Number: 20120211.1038921

SCHMALLENBERG VIRUS - EUROPE (16): UPDATE, OIE
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A ProMED-mail post
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ProMED-mail is a program of the
International Society for Infectious Diseases
http://www.isid.org

In this update:
[1] Germany, update
[2] France, update
[3] UK, OIE follow-up report
[4] EFSA technical supporting report and forecast
[5] UK, media-derived overview

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[1] Germany, update
Date: Fri 10 Feb 2012
Source: FLI web-site, news [edited]
http://www.fli.bund.de/en/startseite/current-news/animal-disease-situation/new-orthobunyavirus-detected-in-cattle-in-germany.html

Current Information on Schmallenberg virus - last updated 10 Feb 2012
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In Germany animals from 434 holdings have been tested positive for Schmallenberg virus [SBV] so far. The cases occurred in 13 cattle holdings, 402 sheep holdings and 19 goat holdings. Affected federal states are North Rhine-Westphalia (7 cattle, 185 sheep, 6 goat holdings), Lower Saxony (1 cattle, 62 sheep, 3 goat holdings), Hesse (41 sheep holdings, 2 goat), Schleswig-Holstein (1 cattle, 44 sheep holdings), Rhineland-Palatinate (2 Bison, 24 sheep, 3 goat holdings), Baden-Wuerttemberg (1 cattle, 3 sheep, 4 goat holdings), Brandenburg (7 sheep holdings), Thuringia (10 sheep holdings), Saxony-Anhalt (4 sheep holdings), Hamburg (1 cattle, 4 sheep holdings), Bavaria (9 sheep holdings), Saxony (9 sheep holdings) and Mecklenburg-Western Pomerania (1 goat holding).

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[2] France, update
Date: Fri 10 Feb 2012
Source: French Ministry of Agriculture - Animal Diseases - News [machine-transl, summarised, edited]
http://agriculture.gouv.fr/maladies-animales

Schmallenberg virus [SBV] identified in northern France on sheep
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The presence of SBV has just been confirmed on 44 additional farms, in lambs. In total, 94 farms have been found affected so far, in 18 districts mainly in northern France. The districts are 02 (Aisne), 08 (Ardennes), 10 (Aube), 14 (Calavados), 50 (Manche), 52 (Haute-Marne), 54 (Meuthe-et-Moselle), 55 (Meuse), 57 (Moselle), 59 (Nord), 60 (Oise), 62 (Pas-de-Calais), 67 (Bas-Rin), 76 (Seine-Maritime), 80 (Somme), 86 (Vienne), 87 (Haute-Vienne), 88 (Vosges).

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[A map of France with the district numbers, indicating the locations of all SBV outbreaks as of 6 Feb 2012, is available in slide 5 of the French presentation to SCFCAH (meeting of 7 Feb 2012) ; see at
http://ec.europa.eu/food/committees/regulatory/scfcah/animal_health/presentations/0708022012_schmallenberg_virus_france.pdf.

The presentations of the other 4 affected countries as well as of EFSA are similarly available at
http://ec.europa.eu/food/committees/regulatory/scfcah/animal_health/presentations_en.htm#0708022012. - Mod.AS]

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[3] UK, OIE follow-up report
Date: Fri 10 Feb 2012
Source: OIE-WAHID interface, Weekly Disease Information Vol.25 - No.7
http://web.oie.int/wahis/public.php?page=single_report&pop=1&reportid=11612

Schmallenberg virus, United Kingdom
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Information received on 10 Feb 2012 from Dr Nigel Gibbens, Chief Veterinary Officer, Department for Environment, Food and Rural Affairs, Department for Environment, Food and Rural Affairs, LONDON, United Kingdom

Summary
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Report type: Follow-up report No. 2
Start date: 14 Jan 2012
Date of 1st confirmation of the event: 23 Jan 2012
Report date: 10 Feb 2012
Date submitted to OIE: 10 Feb 2012
Reason for notification: Emerging disease
Morbidity: 1.76 percent
Mortality: 0.31 percent
Zoonotic impact: No
Causal agent: Schmallenberg virus

[For the full details of each of the 18 affected farms in 6 of England's south-east districts (Norfolk, Hertfordshire, East Sussex, Kent, Suffolk, West Sussex) please refer to the source URL. Of the 18 positive farms, 12 kept sheep only, 5 had mixed populations (sheep and cattle), one had cattle only. As can be seen in the total (see further), there was -- so far -- only one positive calf, namely on the cattle farm in Hertfordshire. - Mod.AS]

Summary of outbreaks
Total outbreaks: 18
Total animals affected
Species/ Susceptible*/ Cases**
Sheep/ 5752/ 79
Cattle/ 731/ 1
*The number of susceptible animals is the number of breeding sheep present on the farm.
**Cases= New lambs born with limb deformities.

Outbreak statistics
Species/ Apparent morbidity rate/ Apparent mortality rate Apparent case fatality rate Proportion susceptible animals lost*
Sheep/ 1.37 percent/ ***/ ***/ ***
Cattle 0.14 percent/ ***/ ***/ ***

*** Not calculated because of missing information

Epidemiology
Source of the outbreak(s) or origin of infection: Unknown or inconclusive

Epidemiological comments: All farms are in the 'at risk' areas for vector incursion from continental Europe.
Geographical coordinates of the affected establishments were anonymised by placing the coordinates on a public place in the nearest town. The map provides only an overview about the geographical distribution of the virus to assist in epidemiological analysis.
All outbreaks were confirmed by real-time PCR.

Control measures:
Measures applied: No vaccination, No treatment of affected animals

Measures to be applied: No other measures

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[Commendably, the UK report includes only breeding ewes under "susceptible population." The above follow-up report No 2 includes a map showing the approximate locations of the 18 outbreaks.

An interactive map map with all 29 outbreaks accumulated so far is available at http://web.oie.int/wahis/public.php?page=event_summary&reportid=11539. - Mod.AS]

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[4] EFSA technical supporting report and forecast
Date: 6 Feb 2012
Source: EFSA (European Food Safety Agency) web-site, Supporting Publications 2012:EN-241 [edited]
http://www.efsa.europa.eu/en/supporting/pub/241e.htm

"Schmallenberg" virus: likely epidemiological scenarios and data needs (Question number: EFSA-Q-2012-00232)
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Summary
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Since autumn 2011, a previously unknown virus, provisionally named as "Schmallenberg" virus (SBV), has been reported in ruminants (cattle, sheep and goats) from Germany, The Netherlands, Belgium, the United Kingdom and France. In January 2012, the European Commission requested scientific assistance from EFSA under the provisions of Article 31 of Regulation (EC) No 178/2002. Among others, a preliminary analysis of the likely epidemiological scenarios that could be observed in the next months was requested, based on the existing knowledge of viruses of the Simbu virus serogroup and other vector borne epidemics in the region. This report provides likely epidemiological scenarios and data needed to improve the understanding of the disease spread and impact of SBV.

The report mainly focuses on animal health aspects. Current knowledge suggests that it is unlikely that SBV can cause disease in humans and as stated in the rapid risk assessment carried out by ECDC (ECDC, 2011). No additional information has since become available to invalidate this assessment. However, EFSA and ECDC are closely monitoring the situation in order to address public health concerns should these arise.

There is currently very limited knowledge specifically related to SBV. Available information on the SBV genome suggests that this virus is part of the Simbu serogroup of the Bunyaviridae family. SBV has been detected in ruminants. Main clinical signs observed in cattle are fever, loss of appetite, up to 50 percent reduction in milk yield and, in rare cases, severe diarrhoea, for approximately one week. SBV has also been detected in association with a variety of congenital abnormalities observed in stillborn or newborn lambs and calves.

In the absence of SBV specific knowledge regarding pathogenesis of SBV infection, an analogy was made with knowledge on Akabane virus, another representative of the Simbu serogroup. It is known that the pathogenic effects of infection with Akabane virus are only seen when the virus exceeds the geographical boundaries of the endemic area and infects susceptible animals in early stage of pregnancy. Such a situation is likely to occur at the edges of an endemic area and may be due to the movement of either infected hosts or infected vectors.

Without knowing the susceptibility to SBV in animal populations throughout the EU, and assuming that SBV induces a strong immunity similar to Akabane virus, 3 types of epidemiological situations can be envisaged: i) areas where a recent incursion might have occurred in populations not previously exposed to the pathogen, that is naive populations, causing clinical disease in adult animals and, at a later date as consequence of infection of dams, malformation in foetuses; ii) areas where incursion occurred in the past and part of the ruminant population is immune and where congenital malformations are not observed or observed at a low level (mainly not reported); and iii) areas where no virus incursion occurred but a susceptible population is present. Surveillance data, as proposed in this report, should be collected by and shared between Member States in order to assess the immune status of animal populations, the impact of SBV infection, and further spread throughout EU. This should include data from serological surveillance also in areas where SBV has yet not been reported.

Due to limited information on the epidemiology of SBV, EFSA used a bluetongue virus (BTV8) model to assess under which conditions SBV could spread into susceptible populations. BTV8 was chosen because; i) BTV8 is an exclusively vector transmitted diseases as are other Simbu serogroup viruses ii) BTV8 and SBV are circulating in the ruminant population iii) information is available regarding BTV8 in Europe whereas there has only been one case report for viruses of the Simbu serogroup in Europe. Assuming that SBV is a non-direct transmissible, vector borne, infectious disease, that vector parameters for the spread of SBV are those for BTV8, and using indications on SBV viraemia given by a preliminary experimental infection in cattle, the hypothetical scenarios show that, depending on the temperature and the number of vectors, SBV might spread further in susceptible populations. Whenever the number of vectors per host and the temperature are above a specific threshold there is a possibility of a wider disease epidemic affecting more Member States. EFSA proposes a coordinated data collection in all Member States in 2012 on the incidence and prevalence of the disease, number of malformed foetuses, as well as the presence of the virus in dams.

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Communicated by:
Sabine Zentis
Castleview Pedigree English Longhorns
Gut Laach
52385 Nideggen
Germany

[The full technical report (31 pages) is available at http://www.efsa.europa.eu/en/supporting/doc/241e.pdf. It includes part 5 "Uncertainties" which is herewith copied for the convenience of subscribers:

"Viraemia duration in naturally infected animals and the range of susceptible species is currently unknown. At this stage it is impossible to exclude other routes of transmission such as direct transmission and the epidemiological role of transplacental transmission on the spread of disease but we also do not know if SBV can be transmitted vertically (i.e. transmitted from parent to offspring) in the vector.

The importance of risk factors related to animal production and management such as exposure to vectors or gestation period at the time of infection are also not fully understood. The current epidemiological situation is unclear for several reasons. Our knowledge on the geographical distribution of the disease is based on the reported cases, mainly of lambs, calves and kids showing malformations of the AHS type with laboratory confirmation of SBV infection by RT-qPCR.

It cannot be excluded that a much larger geographical area is affected due to under reporting. At a European level, notification is currently not obligatory in all MS. Case definitions, if available, vary between countries but are generally based on the identification of malformations in newborns or stillborn animals. Diagnostic confirmation is done by RT-qPCR, a test which is not completely validated. A 1st assay from the FLI-Institute was updated by a 2nd test with an optimized performance; both assays are under further validation. However, the tests proved to be sensitive and specific as well as reproducible as repeatable in several laboratories and were used for the testing of several hundreds of samples including samples from the 1st animal experimental infection trials. Antibody detection is at the moment restricted to the virus neutralisation test and the indirect immune-fluorescence test (iIF) hence a high throughput antibody detection serological tool to be used in large scale surveys is not available. Therefore, at this point in time, the prevalence of infection cannot be estimated."

The technical report provides the following information on the early stages of the event: "The detection of SBV in 2011 has been associated with clinical signs in adult cattle, which were observed in summer and early autumn, and with congenital malformations in newborn animals, mainly lambs, starting from mid-December 2011."

The earliest information on the emerging syndrome was posted by ProMED-mail on 15 Nov 2011, based upon rumors published in a provincial Dutch newspaper, reporting an undiagnosed ephemeral clinical disease in dairy cattle, characterised by temperature elevation, milk production drop, and diarrhea in some of the affected cattle. It was stated by the Germans and Dutch authorities that the said signs had started in August 2011. From an Internet search it becomes apparent that a significant number of dairy farms indeed suffered the said disease already in early August 2011; see, for example, at http://www.agrar.de/landfrauen/forum/index.php?topic=39331.0 where a German blogger communicated, on 17 Aug 2011, "a new cattle disease in northern Germany, reported by the NDR (North German Broadcasting)." More than 66 cattle holdings were mentioned as affected ("and certainly there are more; I have talked to a feeding consultant, and only within his company's clientele there were 60 affected farms"). The said information seems to have remained "under the radar" of international animal-disease surveillance bodies (including ProMED-mail) for more than 2 months. - Mod.AS]

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[5] UK, media-derived overview
Date: Fri 10 Feb 2012
Source: Financial Times [edited]
http://www.ft.com/cms/s/2/ecaeb6c0-5203-11e1-a30c-00144feabdc0.html#axzz1m1lJkh8A

British lambs face viral danger
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A new livestock disease -- 1st detected 6 months ago in Germany -- threatens farmers in northern Europe, including Britain. It causes a high level of miscarriage and birth defects in lambs and calves.

Veterinary scientists are scrambling to understand Schmallenberg virus, which is named after the site of an early outbreak. They believe the virus is spread by midges -- like bluetongue fever, another serious disease of ruminants.

Schmallenberg has hit several hundred farms in Germany, the Netherlands, Belgium and north-east France. Infected midges, blown across from the continent, are probably responsible for the dozen or so outbreaks reported in Britain. All the UK farms affected are in south-east England and East Anglia.

"Everyone is wondering whether the cases detected so far are just the tip of the iceberg and this will turn out to be a serious threat to livestock farmers -- or whether it will soon disappear again," says Paul Mertens, head of the vector-borne diseases programme at the UK Institute for Animal Health.

Although the virus can cause symptoms in adult livestock, such as fever, diarrhoea and reduced milk yield, its main impact is on the growing foetus. Horrific malformations and miscarriages occur in an estimated third to a half of cases when the mother is infected. Experts, therefore, fear that many more cases will be reported during the spring lambing and calving seasons.

According to an initial assessment by public health authorities in the Netherlands and a follow-up analysis by the European Centre for Disease Prevention and Control, the risk to humans from Schmallenberg virus is very low. But the UK Animal Health and Veterinary Laboratories Agency points out that there are still some uncertainties, so farmers and vets are advised to "take sensible hygiene precautions when working with livestock."

Schmallenberg is a member of a large viral family transmitted mainly by insects and affecting ruminant animals, called the orthobunyavirus group. Few are known to cause serious human disease. When bluetongue emerged suddenly as a serious threat to European livestock in 2006/07, animal health researchers in the public and private sectors moved very fast to develop and use a vaccine against the viral strains responsible. "Bluetongue was an almost perfect scenario for stopping a disease through vaccination," says Mertens. "It has been eradicated in the UK."

Whether it will be technically possible to develop a Schmallenberg vaccine so fast -- and whether the disease is serious enough to justify a crash programme to do so -- remains to be seen.

[Byline: Clive Cookson]

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[The appearance of SBV in the news columns of leading national and international newspapers such as the FT, as well as the inauguration of a dedicated web-site of EFSA, an EU agency (see at http://ec.europa.eu/food/animal/diseases/schmallenberg_virus/index_en.htm) are indicative of SBV gaining public attention. Different case definitions and reporting criteria are applied by the affected countries (compare the examples further); planning coordinated surveillance, control and research activities deserve to include streamlined reports. A common European map, similar to the one used to follow-up the BTV-8 epizootic, will help.

Germany's SBV map as of 10 Feb 2012 is available at
http://www.fli.bund.de/fileadmin/dam_uploads/tierseuchen/Schmallenberg_Virus/Karten/Map_Schmallenberg_20120210.jpg. The data included are:
Cattle (blue dots; positive 13). The cattle data include the cases of clinical disease during the late summer/early fall of 2012.
Sheep (red dots; positive 402).
Goats (green dots; positive 19).

Netherlands' SBV map as of 10 Feb 2012 is available at http://www.vwa.nl/onderwerpen/dierziekten/dossier/schmallenbergvirus. The respective table is available at http://www.vwa.nl/txmpub/files/?p_file_id=2201855. The data included are:
Cattle (blue dots): complaints 281, tested 207, positive 4 (in difference wit Germany, only farms with congenital malformations included, thus excluding the positive clinical cases in summer/fall 2011),
Sheep (red dots): complaints 172, tested 151, positive 89.
Goats (yellow dots): complaints 21, tested 19, positive 5.

Belgium's SBV map as of 10 Feb 2012 is available at http://www.afsca.be/_pictures/users/Schmallenberg_20120210_004.jpg.
The data included are:
Cattle (green dots; positive 7).
Sheep (blue dots; positive 95).
Goats (red dots; positive 1).

Totally, up to 10 Feb 2012, at least 758 farms have been affected in the 5 counties combined, including 708 sheep farms, and 25 each cattle and goat farms, with Germany by far the most severely affected country (402 reported sheep farms). - Mod.AS.]

See Also