Datum
21 februari 2012

noodzakelijk. Het ECDC is het eens met de risk assessment, die overeenkomt met
de inschatting die in andere aangedane EU landen is gemaakt. ECDC sprak haar
waardering uit voor de leidende rol die Nederland inneemt met betrekking tot het
uitsluiten van het risico voor de volksgezondheid én de snelle en zorgvuldige
risico inschatting die voor ECDC zeer waardevol was.

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33/2012 CIb LCI RC/AT li

Monitoring
Vraag: Vinden de deskundigen dat het huidige, passieve, monitoringsysteem
afdoende is om infecties bij mensen op te sporen?
Antwoord: Het huidige, passieve, monitoringsysteem bestaat eruit dat personen
die klachten krijgen gepaard gaande met koorts (>38 graden) binnen 14 dagen
nadat zij contact hebben gehad met besmet vee (of geboortemateriaal daarvan),
geadviseerd wordt om contact op te nemen met de lokale GGD. Dit betreft
voornamelijk veehouders en dierenartsen. Er zijn enkele meldingen geweest maar
bij geen van deze gevallen is een relatie met het Schmallenbergvirus
waarschijnlijk of vastgesteld. Omdat er op dit moment geen aanwijzingen zijn dat
het Schmallenbergvirus humane infecties kan veroorzaken, beschouwen de
deskundigen het huidige, passieve, monitoringsysteem als afdoende. De
deskundigen zijn van mening dat het niet noodzakelijk is om het huidige passieve
monitoringsysteem uit te breiden. In andere EU landen waar het
Schmallenbergvirus is aangetoond, wordt in het geheel niet op
gezondheidsklachten gemonitord; het Verenigd Koninkrijk heeft een vergelijkbaar
systeem met het Nederlandse opgezet.
Zwangere vrouwen
Vraag: Zijn er aanvullende preventieve maatregelen nodig ten aanzien van
zwangere vrouwen of zijn de huidige maatregelen afdoende?
Antwoord: Op dit moment wordt zwangere vrouwen geadviseerd om geen
verloskundige handelingen te verrichten op bedrijven met verdenking van de
aanwezigheid van het Schmallenbergvirus. Zoals eerder benoemd zijn er geen
aanwijzingen die veronderstellen dat het Schmallenbergvirus leidt tot humane
infecties, laat staan tot complicaties bij zwangeren. Ook zijn er vanuit kennis van
gerelateerde virussen en vanuit de lopende monitoring geen aanwijzingen dat
direct contact met geboortemateriaal of geïnfecteerde lammeren of kalveren een
risico vormt voor overdracht naar de mens. Het huidige preventieve beleid voor
zwangeren is dan ook opgesteld vanuit het voorzorgprincipe. De deskundigen
beschouwen deze maatregelen als afdoende en zij merken op dat bestaande
adviezen in verband met het risico op het oplopen van andere zoönosen eigenlijk
voorheen ook al van kracht waren. Wel wijzen de deskundigen op het belang van
goede communicatie over de te nemen preventieve maatregelen richting de
doelgroep.
Vraag: Is aanvullende monitoring noodzakelijk om congenitale afwijkingen bij
foetussen op te sporen?
Antwoord: Er bestaat geen actuele landelijk dekkende registratie van congenitale
afwijkingen. Bestaande registraties hebben te maken met een forse vertraging
met betrekking tot hun meldingen. Er bestaat geen centrale registratie van
afwijkingen geconstateerd op de 20-weken echo’s, dit naast het feit dat de
interpretatie van zowel afwijkingen als causaliteit complex is. De deskundigen
benadrukken dat er geen enkele aanwijzing is dat humane infecties optreden en
leiden tot complicaties bij de foetus. Congenitale afwijkingen worden ook niet
Pagina 2 van 4

Datum
21 februari 2012

beschreven voor nauw verwante virussen die wel humane infecties geven.
Mochten er toch serologische aanwijzingen zijn dat humane infecties kunnen
optreden, dan zal hierover opnieuw overleg plaatsvinden.

Ons kenmerk
33/2012 CIb LCI RC/AT li

Beheersmaatregelen ten aanzien van de vector
Vraag: Zijn er aanvullende maatregelen nodig met betrekking tot de beheersing
en bestrijding van de vector (de knut of de mug)?
Antwoord: De mogelijkheden tot het treffen van preventieve maatregelen ten
aanzien van knutten zijn zeer beperkt. De verschillende soorten knutten hebben
zeer diverse habitats en ecologische niches. Gezien deze diversiteit zijn effectieve
bestrijdingsmaatregelen niet uitvoervaar. Alleen persoonlijke
beschermingsmaatregelen kunnen gedeeltelijk effectief zijn (stal afsluiten, zeer
fijn gaas voor de ramen, insectenspray en –repellants gebruiken) echter het
effect wordt als zeer beperkt ingeschat.
Maatregelen ten aanzien van de mug zijn naar inschatting van de deskundigen
iets realistischer in hun uitvoerbaarheid en effectiviteit (persoonlijke bescherming,
muggen bestrijding). Echter, de deskundigen zijn van mening dat aanvullende
maatregelen met betrekking tot de bestrijding van de vector (knutten en
mogelijkerwijs muggen) onvoldoende zal bijdragen tot het inperken van de
uitbraak. Bovendien is de mogelijke rol van de mug als vector voor dit virus niet
opgehelderd. Dit jaar zal er onderzoek worden verricht naar het mogelijk
voorkomen van Schmallenbergvirus bij verschillende soorten knutten en muggen
in Nederland.
Onderzoek
Vraag: Staan de deskundigen achter het onderzoeksvoorstel, of ontbreekt er nog
essentieel onderzoek?
In het onderzoeksvoorstel van 15 februari wordt voorgesteld om diagnostiek te
verrichten bij personen met koorts en eventuele andere symptomen ontstaan
binnen 2 weken na blootstelling aan geboortemateriaal bij dieren met sterke
verdenking voor infectie met het Schmallenbergvirus. Dit onderzoek loopt
momenteel al. Daarnaast wordt in het onderzoeksvoorstel voorgesteld om een
seroprevalentieonderzoek te doen bij personen met een hoge à priori kans op
blootstelling en een controle groep (sera van personen waarbij bloostelling
uitgesloten/zeer onwaarschijnlijk is) te starten. Dit betekent dat op korte termijn,
bij ongeveer 200 personen (veehouders, dierenartsen) nader onderzoek zal
worden gedaan.
Antwoord: De deskundigen kunnen zich vinden in het huidige onderzoeksvoorstel.
Zij benadrukken dat het van belang is om zo spoedig mogelijk uit te sluiten dat
het Schmallenbergvirus overgedragen kan worden naar de mens. Indien het
voorgestelde onderzoek daartoe aanleiding geeft zal het deskundigenberaad
direct weer bij elkaar worden geroepen, om de interpretatie van deze bevindingen
te bespreken. Bedacht moet worden dat de interpretatie van de niet optimaal
gevalideerde serologische testen complex kan zijn. De verwachting is dat de
resultaten van het seroprevalentieonderzoek begin april beschikbaar zullen zijn.
De deskundigen onderschrijven het belang van zorgvuldige communicatie rondom
dit onderzoek.
Conclusie
De deskundigen komen tot de conclusie dat het huidige beleid, gebaseerd op de
risico-inschatting van december 2011, op dit moment afdoende is. Aanvullend
Pagina 3 van 4

Datum
21 februari 2012

serologisch onderzoek zal zo spoedig mogelijk starten om overdracht van het
Schmallenbergvirus naar de mens met zo groot mogelijke waarschijnlijkheid te
kunnen uitsluiten. Mocht er op basis van dit onderzoek daarvoor redenen zijn,
dan zal het deskundigenberaad opnieuw bij elkaar worden geroepen.

Ons kenmerk
33/2012 CIb LCI RC/AT li

Tot een nadere toelichting van deze brief ben ik gaarne bereid.

Hoogachtend,
Prof.dr. R.A. Coutinho
Directeur Centrum Infectieziektebestrijding

Bijlage 1: Deelnemerslijst
Bijlage 2: Risk assessment

Pagina 4 van 4

Bijlage 1. Deelnemers deskundigenberaad Schmallenbergvirus
15 februari 2012

1.

Dhr. R. Coutinho, Directeur CIb, RIVM (voorzitter)

2.
3.
4.
5.
6.

Mw. K.C. Leitmeyer, senior expert Preparedness en Respons, ECDC
Mw. C. Gossner, senior expert Preparedness en Respons, ECDC
Dhr. J.W.M. van der Meer, specialist interne geneeskunde, UMCN
Dhr. A. de Rooij, arbeidshygiënist, Stigas
Mw. C.J. Wijmans, arts infectieziektebestrijding, voorzitter LOI, GGD Hart
voor Brabant
Dhr. W. van der Poel, onderzoekshoofd, viroloog, CVI
Dhr. P. Vellema, hoofd afdeling Small Ruminant Health, GD
Dhr. E.J. Scholte, entomoloog, Centrum voor Monitoring Vectoren, NVWA
Mw. M. Nielen, veterinair epidemioloog, Universiteit Utrecht, Faculteit
Diergeneeskunde
Dhr. R.A.A. van Oosterom, veterinair officer, NVWA-BuRO
Dhr. P.F. de Klerk, Chief Veterinary Inspector, NVWA
Dhr. J.G. Aarnoudse, gynaecoloog, UMCG
Dhr. M.D. de Jong, viroloog, AMC Amsterdam
Mw. M.P.G. Koopmans, viroloog, hoofd afdeling virologie, RIVM
Mw. C. Reusken, viroloog, RIVM
Dhr. J.H.T.C. van den Kerkhof, arts infectieziektebestrijding, RIVM
Mw. M.A.B. van der Sande, epidemioloog, hoofd afdeling epidemiologie,
RIVM
Dhr. Van Pelt, epidemioloog, RIVM
Mw. K. Maassen, senior onderzoeker, RIVM
Mw. A. Timen hoofd Preparedness en Respons Unit, RIVM (secretaris)
Mw. L.D. Isken Beleidsmedewerker Respons, RIVM (notulist)

7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.

A. van Leeuwenhoeklaan 9
3721 MA Bilthoven
Postbus 1
3720 BA Bilthoven
www.rivm.nl
KvK Utrecht 30276683
T 030 274 91 11
F 030 274 29 71
info@rivm.nl

Risk Profile Humaan Schmallenbergvirus

A. van Leeuwenhoeklaan 9
3721 MA Bilthoven
Postbus 1
3720 BA Bilthoven
www.rivm.nl
KvK Utrecht 30276683
T 030 274 91 11
F 030 274 29 71
info@rivm.nl
Datum
21 december 2011

Prepared by Chantal Reusken and Marion Koopmans
National institute of public health and the environment, Bilthoven, The
Netherlands.

Ons kenmerk

Input from
Marieta Braks, Kitty Maassen, Hans van den Kerkhof and Roel Coutinho (RIVM).
Petra Kock, (GD)
Wim van der Poel, Johan Bongers (CVI)
Rudy Meiswinkel, (Culicoides expert)
Ab Osterhaus (Erasmus MC)
Menno de Jong (UVA, AMC)
Martin Beer (FLI, Germany)
Toos Waegemaekers (RIVM/GGD)

Situation assessment
On November 18th, 2011 scientists from the Friedrich Loeffler institute in
Germany identified the presence of viral sequences in serum from cattle affected
by a specific febrile syndrome. The sequences show homology to the L, M, and S
gene segments of viruses from the family Bunyaviridae, genus Orthobunyavirus.
Full details of the virus characterization are needed before definitive conclusions
can be drawn about the taxonomic assignment. However, based on the
preliminary data, the virus – named Schmallenberg virus- is most related to
genomic sequences of Shamonda-, Aino-, and Akabane-virus, all grouped within
the Simbu serogroup and known as viruses that may cause illness in
ruminants(1).
Based on the findings sofar, the infection is considered to be the likely cause of a
clinical syndrome that occurred in late summer in cattle (fever, decreased milkproduction, diarrhea) in Germany and the Netherlands, and more recently in
sheep in The Netherlands (intra-uterine malformations). Evidence for association
of the virus with the illness in cattle and sheep in The Netherlands comes from
the detection of viral gene sequences by RT-PCR in a significant proportion of sera
from cattle with the syndrome while 150 sera from healthy cattle were negative.
Furthermore, the virus was detected in brain material from lambs with congenital
abnormalities (Communicated by Beer, Freidrich Loeffler institute, Van der Poel,
CVI, Vellema, Kock, Mars GD)
Sofar, Schmallenberg virus has been identified in the North Rhine-Westphalia
(Germany) and the Netherlands. Based on an initial assessment of the clinical
syndrome in The Netherlands, the infection appears to be dispersed across the
country with no apparent geographic clustering.
As the family Bunyaviridae contains several medically important viruses, a risk
assessment was made to identify potential human health risks.

Pagina 1 van 8

Taxonomy
Family: Bunyaviridae
Genus: Orthobunyaviruses
Putative serogroup: Simbu serogroup (classification solely based on sequence
data!).
Virus: Schmallenberg virus.

Datum
21 december 2011
Ons kenmerk

Viruses in the family Bunyaviridae are classified into five genera:
Orthobunyavirus, Hantavirus, Nairovirus, Phlebovirus and Tospoviruses. The
Bunyaviridae are enveloped, negative sense RNA viruses whose genome
comprises three segments: small (S), medium (M) and large (L). The S segment
encodes for the nucleocapsid and a nonstructural protein, NSs. The M segment
encodes for the surface glycoproteins Gn and Gc, whereas the L segment encodes
the viral polymerase (2). The surface proteins mediate attachment, cell fusion
and haemagglutination, and therefore are thought to contain important virulence
determinants. Neutralizing antibodies are reportedly directed against epitopes on
the G1 surface glycoprotein.
Medically important viruses within the family are amongst others Oropouche virus
(genus Orthobunyavirus), Crimean-Congo hemorrhagic fever virus (genus
Nairovirus), Sandfly fever virus and Rift-Valley fever virus ((both genus
Phlebovirus), Sin Nombre virus and Puumalavirus (genus Hantavirus). At least 30
orthobunyaviruses have been associated with human disease, causing selflimiting, although sometimes severe, febrile illness (e.g. Oropouche virus).(3, 4).
For the purpose of this risk assessment, we focus on information on viruses
belonging to the Orthobunyavirus genus. This contains some 170 virus isolates,
assigned to 48 distinct species, covering 18 serogroups, including the Simbu
serogroup (5). Serogroups within the genus are based on cross-hemagglutination
inhibition and antibody neutralization relationships, and are further clustered into
5 serocomplexes. The Simbu serogroup comprises 25 viruses of which Akabane
virus, Aino virus, Shamonda virus, Shuni virus, Jatobal virus, Oropouche virus
and Iquitos virus are examples. Phylogenetic analysis has distinguished Simbu
viruses that affect ruminants (Akabane, Aino, Shamonda) from the medically
relevant viruses Oropouche and Iquitos virus, suggesting that they are
epidemiologically distinct.
Transmission cycle.
Orthobunyaviruses are mainly transmitted by mosquitoes (Culicidae) or midges
(Culicoides) and the natural life-cycles of the viruses involve a limited number of
warm-blooded vertebrates, which can act as amplifying hosts and may aid in
dissemination of virus through migration. Infection of these hosts is usually
inapparent, although the animals develop sufficient viremia for biting arthropods
to acquire infection. Humans are usually considered dead-end hosts. Exceptions
are found in the Simbu serogroup, to which the Schmallenberg virus putitatively
belongs: humans infected with Oropouche virus and Iquitos virus develop
significant viremia such that uninfected midges can acquire the virus (3). As a
consequence of this, epidemic spread of these viruses resulting in dengue-like
outbreaks has been observed, particularly in South America (Iquitos virus:
Amazon region of Peru; Oropouche virus: Brazil, Panama, Peru, and Trinidad.).
The Shamonda-, Aino-, and Akabane-viruses to which the Schmallenberg virus is
closely related at the nucleotide level (1) are all mainly transmitted by Culicoides
spp.

Pagina 2 van 8

Reservoirs.
Orthobunyaviruses, Simbu serogroup are found in a wide variety of reservoirs
including wildlife (sloths, marmosets) and livestock (cattle, pigs, goats). Akabane
virus has been found in cattle, buffalo, sheep, camels, deer goats, horses and
dogs. Zoonotic and human-to-human transmission has been described for
Oropouche virus and is suggested for Iquitos virus.

Datum
21 december 2011
Ons kenmerk

Vectors.
The Shamonda-, Aino-, and Akabane-viruses, all closely related to Schmallenberg
virus at the nucleotide level, are transmitted mainly by Culicoides spp. (1).
Mosquitoes have been implicated also, but their role is expected to be minor
compared to that of midges.
The national checklist states 26 species of Culicoides to occur in the Netherlands,
which is about half the number found in neighbouring Germany. During the recent
bluetongue outbreak, Culicoides spp. were captured in the near vicinity of cattle
throughout the Netherlands. The survey showed that C. imicola, the principal
vector for bluetongue virus in Africa and Southern Europe, is not present in the
Netherlands. Subsequently, it was demonstrated that local Culicoides involving
multiple species were responsible for the transmission of bluetongue in the
Netherlands (6, 7). Elsewhere in the world, Akabane virus, Shamonda virus and
bluetongue virus are transmitted by Culicoides belonging to at least three
subgenera, including the subgenus Avaritia. In Australia Akabane virus is
transmitted by the same Culicoides species that transmits bluetongue virus,
namely the cattle dung inhabiting C. brevitarsis (8). In Southern Europe
bluetongue virus is transmitted by C. imicola, the known vector for Shamonda
virus in Nigeria (9) and which, like C. brevitarsis, belongs also to the subgenus
Avaritia. Other virus vectors belonging to this subgenus are C. dewulfi, C.
obsoletus, C. scoticus and C. chiopterus, all implicated in the transmission of
bluetongue in Northern Europe, including the Netherlands. Other Culicoides found
quite frequently in association with cattle in the Netherlands are various species
of the subgenus Culicoides, better known as the Pulicaris Complex, and includes
C. pulicaris, which has been implicated also in the transmission of bluetongue (6,
10) .
The bluetongue outbreak in the Netherlands demonstrated clearly that endemic
Culicoides not previously implicated in the transmission of the virus, are in fact
efficient vectors
Little is known about the host preferences of midges in Europe. Two recent
studies (11, 12) conducted in northern Europe deal with the feeding habits of
midges belonging to two subgenera, i.e. Avaritia and Culicoides:
The first study involved some of the most common and abundant species of biting
midges found in Denmark, i.e. Culicoides obsoletus, C. scoticus, C. pulicaris and
C.punctatus. The blood meals of 115 freshly engorged midges were identified and
revealed that a variety of mammal and avian hosts had been attacked; these
included cattle, roe deer, horse, mallard and wood pigeon. Cattle were the
preferred host and constituted 73.9% of the total bloodmeals identified;
unexpectedly,the common wood pigeon was the next most commonly attacked
host, with a frequency of 18.3% (11).
In the second study, conducted in Germany, a total of 177 Culicoides blood meals
were analysed; 115 (65%) tested positive for vertebrate blood. Of these 63.5%
were assigned to a species; cattle again proved to be the most attractive host
(79.5%, n = 58) even in the immediate presence of other large vertebrates . Pigs
and/or horses maintained on the same farm, were attacked also by biting midges,
but at a distinctly lower rate (pigs 13.7%, horses 2.7%). Game animals appeared
to be less attractive as only a few engorged midges had taken a blood meal from

Pagina 3 van 8

red deer (4.1%). None of the 177 blood meals analysed tested positive for sheep
(12).

Datum
21 december 2011
Ons kenmerk

These results show that biting midges of the C. pulicaris and C. obsoletus species
groups feed on a wide range of vertebrate hosts, but with a distinct preference for
cattle even in the near presence of other types of livestock.
Clinical manifestation of orthobunyaviruses in human.
Currently, Schmallenberg virus has not been related to human disease.
Shamonda-, Aino-, and Akabane-virus which are genetically most related to the
Schmallenberg virus are only found in livestock. However, zoonotic potential of
this virus cannot be excluded as
1) Viruses within the Simbu serogroup (Oropouche virus and Iquitos virus)
are known to be zoonotic and cause human outbreaks (13).
2) Genetic reassortment among members of the same serogroup within the
Orthobunyavirus genus occurs in nature and has led to the emergence of
new viruses, occasionally with increased pathogenicity. This may increase
the zoonotic potential of these viruses as reassortment might lead to
change of host reservoirs (14-17).
3) Viruses within other serogroups of the genus orthobunya are zoonotic.
Examples: California encephalitis virus, La Crosse encephalitis virus,
Tahyna virus, Bataivirus, Inkoovirus, Snowshoe hare virus.

Oropouche virus, that like Schmallenberg virus is a member of the Simbu
serogroup, causes a febrile disease often associated with headache, dizziness,
photophobia, skin rash, myalgias, arthralgias and malaise, which may be long
lasting and sometimes relapsing 2-3 weeks after initial onset of symptoms (18).
Patients with Oropouche fever usually recover after 2–3 weeks of disease without
known sequelae or recorded mortality (19). The very limited information available
indicates that Oropouche virus infection is associated with viremia that declines
quickly until the fifth or sixth days of illness (18), and that the virus has been
recovered from the cerebral spinal fluid (CSF) in association with clinical
meningitis (20).
Iquitos virus, a member of the Simbu serogroup to which Schmallenberg virus
belongs, causes illness that includes symptoms of fever, general malaise,
headache, retro-orbital pain, myalgia, arthralgias and chills. Respiratory
manifestations were observed in 38% of the cases.
Gastrointestinal manifestations in 75% of the cases, including diarrhea, vomiting,
nausea (13).
There have been no reports of unusual human illness form the regions where
Schmallenberg virus has been identified. The veterinary health service indicates
that farmers from affected farms have been specifically asked for symptoms of
illness, and have reported none (Kock, pers. comm..)
Human diagnostics.
In Europe Oropouche virus diagnostics are available in Hamburg (BernhardNocht-Institut
für Tropenmedizin, dr. Schmidt-Chanasit). This includes IFA, reversetranscriptase (rt) PCR, VI. However, based on the findings sofar, it is unlikely that
these methods would be suitable to detect exposure to Schmallenberg virus in
humans.
For Oropouchovirus, real-time- (RT-) PCR showed high titers of Oropouchevirus
in acute-phase serum samples from febrile patients. A study in South America

Pagina 4 van 8

showed serological evidence for infection in 113 of 119 acutely febrile patients
with paired serum samples. Oropouche virus infections were confirmed by
seroconversion (n=76) or high antibody titers (n=37), determined both by HI
assay and IgM-ELISA (21)

Datum
21 december 2011
Ons kenmerk

Currently there is no serology available for Schmallenberg virus. A commercially
available test for detection of antibodies to Akabane virus did fail to detect
antibodies in serum from Schmallenberg virus infected cattle (Beer , pers.
comm.). This indicates that serological tests that are currently available for
Simbu serogroup viruses might not be applicable for Schmallenbergvirus .
Therefore, diagnostics currently rely on detection of viral infection by RT-PCR.
For this purpose, the Friedrich Loeffler institute has shared information with the
CVI and RIVM in The Netherlands. Validation of the use of RT-PCR for diagnosis of
infection requires more data on infection kinetics.
Scientists from the FLI have isolated the virus and are able to culture it in
hamster cells (Beer pers. comm.) This will enable the development of IFA-based
tests and neutralization assays that can be used for antibody detection.
Risk factors for human exposure.
In general, infection risk for humans of arboviruses is closely related to high
densities of infected arthropods. High population densities of the midge vector of
Oropouche virus coincide with human epidemics (22). Given the viremic phase,
blood-borne transmission of these viruses is possible.
There is no evidence for direct zoonotic transmission of Simbu serogroup viruses
from ruminants to humans. If there would be a potential for direct zoonotic
transmission, presence at or in the direct surroundings of affected farms would be
expected to be a risk factor. The birth defects in lambs have resulted in an
increased need for assistance from veterinarians during parturition (Vellema,
pers. comm.). There is no information about possible presence of virus in
amniotic fluid. From the California serogroup of orthobunyaviruses it is known
that these viruses are susceptible to common disinfectants (1% sodium
hypochlorite, 2% glutaraldehyde, 70% ethanol, formaldehyde) like all lipid
enveloped viruses. They are sensitive to heat; infectivity lost at 50-60°C for at
least 30 min) and do not survive outside the host for long periods (23).
Conclusion/recommendations.
1) Based on the considerations mentioned above, zoonotic transmission of
Schmallenbergvirus can not be excluded but is considered unlikely.
2). The clinical syndrome associated with Schmallenberg virus in cattle peaked
during the months August and September. Currently the circulation/transmission
of Schmallenberg virus in cattle seems to have faded out. The recent increase in
delivery of malformed lambs – if proven to be related to the infection- is likely
resulting from intra-uterine exposure during prior months.
3). If one would assume that Schmallenberg virus has zoonotic potential, there is
no acute risk for human population at present (December 2011) when considering
the vectorial transmission route (most likely midges). However, exposure risk
during abortion or delivery of affected ruminants due to Schmallenberg virus is
unknown.
4). There have been no reports of unusual illness in humans in the months when
the cattle syndrome peaked.

Pagina 5 van 8

5) The outbreak in cattle in Germany and the Netherlands could reoccur in the
vector season in 2012 (based on epidemiology other orthobunyaviruses and
bluetongue virus: survival in midges during winter). In this case these outbreaks
should be monitored closely from a public health perspective: an increased
awareness for putative zoonotic events is indicated, for instance by
implementation of a surveillance system.

Datum
21 december 2011
Ons kenmerk

6) We advice to initiate a monitoring system for diseases among professionals
(farmers, veterinarians) that have been in close contact with abortion products or
who conducted deliveries of affected calves/lambs. They will be advised to contact
the local municipal health services. The national center for control of infectious
diseases (LCI) will coordinate this system.
7) Currently, diagnostic methods for this virus are limited to RT-PCR, and have
not been validated. Improved diagnostic methods will be developed in the near
future. The CIb is in contact with the FLI and CVI to prepare for laboratory
response, in case such is needed.

Pagina 6 van 8

References.
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Beer M. Undiagnosed illness, bovine- germany, Netherlands (02): new
virus susp. ProMED-mail 2011;Archive nr. 20111119.3404.
2.
Walter CT, Barr JN. Recent advances in the molecular and cellular biology
of bunyaviruses. J Gen Virol. 2011 Nov;92(Pt 11):2467-84.
3.
Hart TJ, Kohl A, Elliott RM. Role of the NSs protein in the zoonotic
capacity of Orthobunyaviruses. Zoonoses Public Health. 2009 Aug;56(6-7):28596.
4.
Elliott RM. Emerging viruses: the Bunyaviridae. Mol Med. 1997
Sep;3(9):572-7.
5.
Calisher CH, editor. Histrory, classification and taxonomy of viruses in the
family Bunyaviridae. New York: Plenum Press; 1996.
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