segunda-feira, 7 de maio de 2012

SCHMALLENBERG VIRUS - EUROPE (37): EPIDEMIOLOGY

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[1]
Date: Fri, 4 May 2012
Source: EFSA supporting Publication 2012:EN-277 [edited]
<http://www.efsa.europa.eu/en/supporting/pub/277e.htm>

"Schmallenberg" virus: analysis of the epidemiological data  (April 2012)
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Summary
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Following a request from the European Commission, the European Food
Safety Authority (EFSA) issued a technical report in February 2012 on
likely epidemiological scenarios in Europe in relation to a recently
detected virus provisionally named "Schmallenberg" virus (SBV) (Simbu
serogroup, Bunyaviridae family, genus Orthobunyavirus), found in
ruminants. The report also included guidance on data to be collected
in Member States, with harmonised case definitions and reporting
guidelines for a minimum dataset at herd/flock level and an extended
dataset at animal level. This second epidemiological report presents
the analysis of the submitted data (1 Aug 2011 - 16 Apr 2012),
updating the previously published report on the epidemiological
situation of SBV.

At present, 8 Member States (Belgium, France, Germany, Italy,
Luxembourg, the Netherlands, Spain and United Kingdom) have confirmed
cases of SBV. All affected Member States have reported the number of
confirmed herds following viral detection by PCR, virus neutralisation
test or serological confirmation and France, Italy, Luxembourg, the
Netherlands, Spain and United Kingdom, have also reported the number
of suspect herds. Switzerland reported herds where malformed offspring
were tested by RT-PCR and the dams by serological testing, all results
were negative. Ireland reported surveillance testing of herds and all
herds were negative. Estonia reported that there have been no suspect
or confirmed herds in the country. Moreover Demark and Norway reported
suspect herds, in all herds foetuses/neonates were tested by RT-PCR
and the results were negative. The total number of SBV confirmed herds
in Europe as of the 16 April 2012 is 3444. No confirmed acute cases
have been reported in adult animals in the year of 2012.

The data shows a decrease in the number of reports of SBV confirmed
herds following a peak in week 9 (27 February - 4 March) of 2012. The
decrease after week 9 is clearly observed in sheep in both numbers of
confirmed and suspect herds. However in cattle there is no clear
decrease and any drop in confirmed and suspect herds could be due to
incomplete reporting for the month of April. The decrease in number of
confirmed herds is most probably linked to the end of the lambing
season in affected countries, the fact that lambs and goat kids born
in April would have been in a stage of gestation potentially
vulnerable to SBV when vector levels were low and other factors
including reporting priorities in Member States.

The data available only allows an impact assessment based upon the
comparison between the number of SBV confirmed herds and the total
number of herds in each affected country by species. For all affected
countries, the number of herds with at least one SBV confirmed animal
is low in comparison with the total number of herds. This analysis
should be interpreted cautiously since under-reporting or lack of
diagnostic confirmation may affect the ratio.

The data provided allows an understanding of the temporal and
geographical distribution of the SBV outbreak. In order to fully
characterise the outbreak and the epidemiology of SBV in Europe,
efforts to obtain comparable data on the number of herds tested, the
number of newborns and foetuses within a herd with arthrogryposis
hydranencephaly syndrome (AHS) type clinical signs and the number of
animals within the herd tested by either direct or indirect laboratory
methods are required. This could be achieved by following up selected
herds or by performing a survey to properly evaluate the impact and
magnitude of the spread of SBV infection. As more data becomes
available the impact assessment for SBV (in particular within herd and
local impact) could be subject to change.

--
Communicated by:
Sabine Zentis
Gut Laach
52385 Nideggen
Germany

[The Report's table of contents is the following:

Summary: p1  
Table of contents: p3 
Background as provided by European Commission: p4 
Terms of reference as provided by the European Commission: p4 
Scope: p4 
Assessment: p5  
1.  Introduction: p5  
2.  Data collection activities in Member States and reporting to EFSA:
p5 
3.  Minimum dataset - herd level: p6 
3.1.  Number of affected herds: p6 
3.2.  Temporal spread: p8 
3.3.  Spatial spread: p13 
3.4.  Characterization of affected herds: p15 
3.5.  Impact analysis: p18  
4.  Recommendations: p22 
Appendix: p23
A.  SBV Data Reporting Guidelines: p23  
Glossary: p31
Abbreviations: p31

Subscribers are encouraged to download the full report at the source
URL. -Mod. AS].

******
[2]
Date: Sat, 5 May 2012
Source: Veterinary Record 2012;170:453 doi:10.1136/vr.e3155 - News &
Reports, Emerging Diseases [edited]
<http://veterinaryrecord.bmj.com/content/170/18/453.1.full>
(subscription)

Serological ELISA for SBV currently being evaluated
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Recent developments in the disease situation surrounding Schmallenberg
virus (SBV) in northern Europe are discussed in the latest outbreak
assessment from the International Disease Monitoring (IDM) team at
Defra. 

In the assessment, which was published on 23 Apr 2012, the IDM team
says that AHVLA laboratories are currently validating a serological
ELISA that has become commercially available in Europe. Defra is
considering how the test could be used for surveillance and whether
there is a potential cost-benefit to such use. The team adds that the
geographical distribution of the disease is still restricted to
north-west Europe, but that this could still change as more cattle
that were infected last year continue to give birth, or as serological
surveillance gives a clearer picture of past exposure. 

The assessment also notes that infected midges, including _Culicoides
dewulfi_ and _Culicoides obsoletus_, have been identified in Belgium,
Denmark and Italy. Germany has reported finding antibodies to SBV in
red and roe deer but, the IDM team says, the significance of this in
terms of a potential wild reservoir host for SBV is not yet known.
Meanwhile, investigations at the Robert Koch Institute in Germany of
60 sheep farmers who had been in close contact with infected animals
had found no evidence of infection using an immunofluorescent antibody
test and a serum neutralisation test. [In the meantime, human
involvement has been further excluded by Dutch investigations; see
ProMED archive number 20120501.1119639. - Mod.AS].

Regarding the pattern of infection, the IDM team notes that Germany,
the Netherlands and Belgium continue to report outbreaks in cattle,
but there have been fewer reports of affected sheep. The same pattern
has been seen in the UK, it says, and coincides with the end of the
lambing season in at-risk areas. 

Noting that all of the cases confirmed in the UK have been found in
counties that were within zones at risk of the incursion of infected
midges in 2011, the IDM team adds: 'It should be noted that it is
possible native midges also became infected at the same time over last
summer and could have contributed to some of the infections'.

The AHVLA reported on its website that, by 30 Apr 2012, 254 farms in
England had reported cases of SBV. Of these, 219 were sheep farms and
35 were cattle farms. [The respective figures as of 4 May were 256,
220 and 36. - Mod.AS].  

The IDM team's latest outbreak assessment is available at
.

--
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