Bluetongue - Europe (05)

International Society for Infectious Diseases
<http://www.isid.org>

[1]&[2] Netherlands
[3] France, OIE
[4] Belgium, OIE

*****
[1] Netherlands

Bluetongue disease was first suspected in the Netherlands on 14 Aug
2006, as a result of classical clinical signs in infected sheep. The
Central Institute for Animal Disease Control (CIDC-Lelystad)
identified BTV infection by RT-PCR (targeting genome segment 10),
confirming these results by detection of BTV specific antibodies in
serum samples collected on 14 Aug 2006. New samples taken from the
field on 15 Aug 2006 and examined at CIDC-Lelystad confirmed BTV
infection, again by PCR and detection of antibodies. The European
Community Reference Laboratory (CRL), at the Institute for Animal
Health at Pirbright in the UK, also demonstrated antibodies to the
bluetongue virus, in sera from animals in the Netherlands.

Since these animals had been raised there, this gives conclusive
evidence of virus transmission in the region, over 500 km further
north within Europe than where it had been detected before. RT-PCR
assays targeting conserved viral genes (segments 1, 5, 7, and 10)
were used to detect the virus in blood samples from seropositive
animals. Sequence analyses of the cDNA products from segment 5, the
NS1 gene, indicated that the virus involved in the outbreak had a
western origin (from Africa or the Americas) and was distinct from
both the previous European [field] strains and the live attenuated
vaccine [strains] recently used to combat the disease in the
Mediterranean region.

The virus serotype is controlled by proteins on the virion surface
(VP2 and VP5). These are encoded by genome segments 2 and 6,
respectively. The virus was isolated on Fri 25 Aug 2006 at Pirbright,
from Netherlands samples directly into Culicoides cells (KC cells,
supplied by colleagues from USDA at The University of Wyoming in
Laramie USA). Viral RNA was extracted from the infected KC cells,
providing a target for RT-PCR assays to detect and identify genome
segment 2 of the new isolate. These assays used 32 new primer sets
that were designed to be specific for the 24 different serotypes of
BTV. Early on morning of Sat 26 Aug 2006, a positive result was
obtained with 3 sets of primers that are specific for BTV-8, a
serotype never previously seen in Europe. Subsequent sequencing of
the cDNA products confirmed the virus as type 8 as well as its
western origin, demonstrating that it belongs to a sub-Saharan
lineage, although this only increases the mystery about how it arrived !
in Northern Europe. See:
< http://www.iah.bbsrc.ac.uk/dsRNA_virus_proteins/BTV-8-Seg-2-tree.htm>.

The Belgian and the French reference laboratories for bluetongue
(BT), namely the Veterinary and Agrochemical Research Center
(CODA-CERVA-VAR, Ukkel, Belgium, Dr Kris de Clercq) and the AFSSA
(Agence francaise de securite sanitaire des aliments, UMR
Afssa/INRA/ENVA, Maisons-Alfort, France, S. Zientara) joined forces
and confirmed independently but in full collaboration by
virus-neutralisation test that the strain of bluetongue virus (BTV)
involved in the current epidemic affecting Belgium, The Netherlands
and Germany was BTV-8.

The VAR isolated the virus on BHK-21 cells on Fri, 25 Aug 2006
(ProMED-mail, 27-28 Aug 2006) and AFSSA isolated the virus from a
different sample also coming from a bluetongue-affected area in
Belgium on Mon, 28 Aug 2006. Both laboratories observed a complete
virus neutralisation with the reference serum against serotype 8 and
a cross-neutralisation with serotype 18. Virus neutralisation assays
at the CRL in Pirbright have now also confirmed the identity of the
Netherlands virus as BTV-8, although there was also some
cross-reaction with type 18.

This cross-reaction is not surprising since it had already been
demonstrated (Reference 1).

Previous sequencing studies of genome segment 2 from the reference
strains of different BTV serotypes have demonstrated a close
relationship between types 8 and 18 (References 2, 3). See:
<http://www.iah.bbsrc.ac.uk/dsRNA_virus_proteins/btv-seg-2.htm>.

In addition, initial sequence analyses of genome segment 6, showed
100 percent identity in a 300 aa region, with the reference strains
of type 8 and type 18. This may also have some influence on the
serological cross reactions detected between these viruses.

Blood samples received by the CRL from outbreaks in Germany (from
Friedrich-Loeffler-Institut, Institute of Diagnostic Virology) have
been tested by real time RT-PCR confirming the presence of BTV.

References:
1. Erasmus B.J. (1990). Bluetongue virus. In Virus infections of
ruminants, Vol. 3 (Z. Dinter & B. Morein, eds.) Elsevier, Amsterdam
and New York, 227-237.

2. S. Maan, N.S. Maan, A.R. Samuel, R. O'Hara, A.J. Meyer, S. Rao &
P.P.C. Mertens (2005). Completion of the sequence analysis and
comparisons of genome segment 2 (encoding outer capsid protein VP2)
from representative isolates of the 24 bluetongue virus serotypes.
Veterinaria Italiana, 40, 484-488.

3. Maan S., Maan N.S, Samuel A.R., Rao S, Attoui, H., & Mertens P.P.C
Analysis and Phylogenetic Comparisons of Full-Length VP2 Genes of the
Twenty-Four Bluetongue Virus Serotypes. Journal of General Virology
(submitted).

--
Peter Mertens
CRL Institute for Animal Health Pirbright, UK

Kris De Clercq
Veterinary and Agrochemical Research Center (CODA-CERVA-VAR)
Ukkel, Belgium

Stephan Zientara
Agence francaise de securite sanitaire des aliments
UMR Afssa/INRA/ENVA
Maisons-Alfort, France

Eugene van Rooij
Central Institute for Animal Disease Control (CIDC)
Lelystad, Netherlands

Bernd Hoffmann
Friedrich-Loeffler-Institut (FLI)
Greifswald-Insel Riems, Germany.

******
[2] Netherlands
Source: Press release, Dutch Ministry of Agriculture, Nature and Food
Safety, 15 Sep 2006 [translated, edited]
< http://www9.minlnv.nl/servlet/page?_pageid=104&_dad=portal30&_schema=PORTAL30&p_item_id=131114>

From the beginning of next week, certain animals will be allowed to
exit infected premises situated within the 20-km zones in Zuid
Limburg and Noord-Brabant provinces. The decision has been taken by
the Minister of Agriculture, Dr Veerman, taking into account animal
welfare issues and the prevention of bottlenecks.

Detailed guidelines and conditions of the restrictions which will
remain valid in the 47 affected farms with ruminants (sheep, goats
and cattle), are to be published soon.

To control the spread of bluetongue in the Netherlands, 2 kinds of
zones have been applied: the "20-km zone" and the "restriction zone".
Originally, a 20-km zone was established in Zuid Limburg. Since 12
Sep 2006, there is a 2nd 20-km zone, namely around Best, in the
province Noord Brabant, following the detection of bluetongue there. [Map at
<http://www.multimap.com/map/browse.cgi?lat=51.5122&lon=5.3929&scale=500000&icon=x>].

Transport of animals between the 2 20-km zones is not allowed.
Netherlands in its entirety has been declared a restriction zone
since 8 Sep 2006.

In the restriction zone, stringent rules are applied to movement of
ruminants; all animals on holdings within this zone have to be
identified and checked for bluetongue by national authorities. The
relevant, official EU legislation is included in Commission Decision
2005/393/EC, updated 14 Sep 2006. The said decision is available at
< http://ec.europa.eu/food/animal/diseases/controlmeasures/com_dec_2005393.pdf>.

The prescribed restrictions are applied to animal movement, not to
the movement of meat. This 150-km restriction zone covers at present
all of Belgium and the Netherlands, areas in the German federal
states of North Rhine Westphalia, Rhineland-Palatinate, Saarland and
Hessen, all of Luxembourg, and parts of France bordering the Benelux
countries.

******
[3] France, OIE
Source: OIE Disease Information, 14 Sep 2006, Vol. 19 - No. 37 [edited]
< http://www.oie.int/eng/info/hebdo/A_CURRENT.HTM#Sec1>


BLUETONGUE IN FRANCE: Follow-up report No. 1

Translation of information received on 7 Sep 2006 from Dr Monique
Eloit, Deputy Director General, General Directorate for Food (DGAL),
Ministry of Agriculture, Food, Fisheries and Rural Affairs, Paris:

End of previous report period: 31 Aug 2006 (see Disease Information,
19 [35], 636, dated 31 Aug 2006).

End of this report period: 7 Sep 2006.

Identification of agent: bluetongue virus. Serotyping in progress.

Date of start of the event: 28 Aug 2006.

Clinical disease: yes.

New outbreaks: 3 new outbreaks involved cattle are reported. On 31
Aug, a farm with 143 susceptible cattle at Beaurieux, Nord division
was positive. Two cattle farms in the Ardennes division at Hierges
(517 susceptible cattle) and Tailly (200 susceptible cattle) were
found positive on 1 Sep 2006.

For maps see:
Hierges (50.10N 4.74E)
at
<http://maps.google.com/maps?q=50.10+4.74+(Hierges)&amp;ll=50.10,4.74&spn=05.0,05.0&amp;t=k&hl=en>
Tailly (49.43N 5.08E)
at
<http://maps.google.com/maps?q=49.43+5.08+(Tailly)&amp;ll=49.43,5.08&spn=05.0,05.0&amp;t=k&hl=en>

Description of affected population:

- outbreak in Beaurieux: the infection was detected within the
framework of reinforced surveillance measures (serological
investigations). No clinical signs in the herd. Only one animal has
been identified as infected (negative results for 37 animals).

- outbreak in Hierges: the infection was detected within the
framework of reinforced surveillance measures (serological
investigations). No clinical signs in the herd. Only one animal has
been identified as infected (negative results for 92 animals).

- outbreak in Tailly: the case was identified following a clinical
suspicion in one animal (salivation, nasal discharge, pyrexia and
mouth congestion).

Laboratories where diagnostic tests were performed:

1) French Agricultural Research Centre for International Development
(CIRAD-EMVT), Montpellier.

Results: ELISA on 4 Sep 2006 was positive
2) Study and Research Laboratory for Animal Pathology and Zoonoses
(LERPAZ, AFSSA(2)), Maisons-Alfort, France

Results: PCR on 31 Aug - 1 Sep and 5 Sep 2006 was positive

Source of outbreaks or origin of infection: vectors.

******
[4] Belgium, OIE
Source: OIE Disease Information, 14 Sep 2006, Vol. 19 - No. 37 [edited]
<http://www.oie.int/eng/info/hebdo/A_CURRENT.HTM#Sec2>

BLUETONGUE IN BELGIUM: Follow-up report No. 2

Translation of information received on 8 Sep 2006 from Dr Luc Engele,
Chief Veterinary Officer, Federal State Service for Public Health,
Food Chain Safety and Environment, Animal and Plant Health Policy
Department, Brussels:

End of previous report period: 1 Sep 2006 (see Disease Information,
19 [36], 641, dated 7 Sep 2006).

End of this report period: 8 Sep 2006.

Identification of agent: bluetongue virus serotype 8.

Date of start of the event: 18 Aug 2006.

Clinical disease: yes.

New outbreaks: 23 new outbreaks were reported in Liege (18 farms),
Limburg (2 farms), Luxembourg (2 farms) and Vlaams Brabant. 4 of the
farms in Liege and the farm in Vlaams Brabant were sheep farms, the
others had cattle. There was a total of 1774 susceptible cattle with
39 cases and 4 deaths. There was a total of 117 susceptible sheep
with 6 cases and 3 deaths. Most farms had one or two animals with
clinical signs with the exception of two farms in Liege which had 3
clinical animals on each farm and one farm that had 12 affected animals.

<http://www.oie.int/cartes/1937_BEL.png> Location of the outbreaks

Laboratory where diagnostic tests were performed: Veterinary and
Agrochemical Research Centre (national laboratory)

Results: In both bovine and ovine specimens: ELISA and RT-PCR were
positive on 18 Aug 2006.

Source of outbreaks or origin of infection: vectors.

The outbreak in France seems to be contained near the border at this
point. In Belgium the outbreak continues to involve new herds, many
of which are in Liege and Limburg in the northeastern parts of the
country near Netherlands and Germany. However, the new outbreaks this
week include the provinces of Luxembourg [Belgium] and Brabant, which
indicates some geographic spread south and centrally. For an outline
map of the provinces please see
<http://www.oultwood.com/localgov/belgium/brabantflemish.htm> and
for an outline map of the affected farms see the links given within
the OIE reports.

This outbreak is a very good example highlighting the value of
information which could have been provided by GIS based information
and mapping systems. Since this disease is spread by _Culicoides_
species, it would be useful to track the spread among farms in more
quantitative terms. We could begin to answer questions about
differences in clustering among the different countries involved as
well as near the borders and we could examine nearest neighbor risks
to mention a few analyses. We would be interested to know if such
studies are under way, as the spread of this new strain of BT virus
would be particularly instructive for patterns and possibilities.

[So far, 210 outbreaks of bluetongue have been reported from the 4
affected European countries. The following data have been derived
from the 15 Sep 2006 update of table 11 (Animal disease situation per
country and per disease), provided by EU's ANIMAL DISEASE
NOTIFICATION SYSTEM (ADNS), available at
<http://ec.europa.eu/food/animal/diseases/adns/table_11_2006/adns_150906_en.pdf>.

Number of bluetongue outbreaks confirmed from 1 Jan 2006 to 15 Sep
2006 (in brackets, last date of confirmation).

Belgium - 88 (14 Sep 2006).
Germany - 71 (13 Sep 2006)
France - 4 (4 May 2006)
Netherlands - 47 (14 Sep 2006).

The disease is expected to disappear when temperatures drop and the
vectors disappear. It remains to be seen if the virus is able to
survive the (northern) European winter.