Re: Schmallenberg virus : new Akabane-like virus in cattle, sheep and goats in Europe
Re: Schmallenberg virus : new Akabane-like virus in cattle, sheep and goats in Europe
Published Date: 2012-03-01 22:58:05
Subject: PRO/AH/EDR> Schmallenberg virus - Europe (22): update
Archive Number: 20120301.1058045
SCHMALLENBERG VIRUS - EUROPE (22): UPDATE
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A ProMED-mail post
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In this update:
[1] UK: prediction
[2] Vaccine and serology needs
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[1] UK: prediction
Date: 1 Mar 2012
Source: Farmers Guardian [edited]
http://www.farmersguardian.com/all-of-the-uk-could-see-schmallenberg-infections/45253.article
Schmallenberg virus [SBV] is likely to be around for at least another year and could spread much further across the UK, a leading animal disease expert has warned.
At a briefing in London on Thursday [1 Mar 2012], scientists outlined 2 extreme scenarios for where disease could go from here.
It is possible, according to Professor Peter Mertens from the Institute of Animal Health, under one scenario Schmallenberg may burn out given the current high levels of infection and the fact infected animals become immune to the virus.
However, he said that was probably "too good to be true" and the major concern for farmers will come when the midge season starts again in the UK later this spring [2012].
If infected midges have over-wintered or if midges pick up the virus from animals in the UK, Schmallenberg could start spreading across the country.
"This virus has the potential to spread across the whole country," Prof Mertens said.
He also warned cattle farmers that evidence from mainland European countries showed the number of cases in calves from cows infected last year [2011] was increasing, whereas infections in sheep were decreasing. This was attributed to the cows longer gestation period compared to sheep [see comment].
Professor Wim Van Der Pol from the Central Veterinary Institute in Wageningen UR in the Netherlands said research conducted there showed it was very unlikely that the virus could infect humans.
[Byline: Alistair Driver]
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Communicated by:
ProMED-mail <promed@promedmail.org>
[Prof Mertens' warning concerning possibility of increased SBV impact in cattle deserves attention. In the Netherlands, the number of affected cattle holdings increased from 2 to 31 within one month; a similar trend has been reported from Germany and Belgium (see figures in final commentary further).
If SBV dynamics are similar to those of Akabane virus, another teratogenic orthobunyavirus of the Simbu serogroup closely related to SBV, then past observations may be predictive.
During a major Akabane epizootic in Israel, 1969/1970, the following observations were made:
In cattle:
1. Arthrogryposis was caused by infection during the 4th to 6th month of pregnancy (mean gestation period in cattle is 280 days).
2. CNS involvement (predominantly hydranencephaly) was caused by infection during the 3rd month of pregnancy.
3. Most affected calves were affected by one of the above phenomena and not by both.
4. Among abnormal calves, males outnumbered females to a significant degree.
In sheep and goats:
1. The agent caused abortions.
2. There was less distinction between Arthrogryposis and hydranencephaly; many newborns suffered from both.
3. The damage was mainly caused during the period between 30-50 days of pregnancy. Practically no damage was caused in fetuses which were older than 50 days during the viraemia.
4. In badly affected flocks, up to 50 percent of all lambs and kids were affected.
5. No clinical symptoms were seen in pregnant animals.
6. Males, twins, and goats were more affected than females, singles, and sheep. - Mod.AS]
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[2] Vaccine and serology needs
Date: Wed 29 Feb 2012
Source: New Scientist [edited]
http://www.newscientist.com/article/dn21529
A deadly, previously unknown virus that triggers abortions in sheep, goats and cattle, is spreading around Europe, causing more trouble for the beleaguered livestock industry. But farmers may have a vaccine to fight it by next year.
Virologists are meeting in Leylstad, the Netherlands this week to discuss Schmallenberg virus [SBV]. Three companies are already testing candidate vaccines. Normally, these would take years to come to market, but faster approval could stop the virus taking hold.
Since SBV was identified in Germany last November [2011], it has caused a wave of sheep abortions across northern Europe and the UK and has now spread to Italy.
The subgroup of the family to which the virus belongs includes Oropouche virus, which infects humans and is the 2nd-most common cause of fever in tropical South America after dengue. SBV's closest relatives, such as Akabane virus found in Japan, Australia and Israel, only infect ruminants, however, so it is thought unlikely to infect humans.
The last animal virus to take Europe by surprise was bluetongue, which, like SBV, is spread by biting midges and which exploded in the same regions of Germany, the Netherlands, and Belgium in 2007. Accelerated approval for a vaccine cleared bluetongue from Europe by 2010.
A sense of urgency might also stop SBV from settling in. "All the tests required for licensing a vaccine would take 2 years," says Peter Mertens, head of insect-borne viruses at the Institute for Animal Health in Pirbright, UK. If governments lift the more onerous testing requirements, vaccines might be permitted after being given to animals and observed for long enough to see whether they are safe, induce effective antibodies, and prevent infection.
In Lelystad, however, researchers will focus on better ways to detect antibodies to the virus, says Martin Beer of the Friedrich Loeffler Institute in Insel Riems, Germany, which 1st isolated the virus and proved its link to disease.
Antibodies reveal which animals have been infected. Rapid tests in time for when midges return in spring will show where the virus spreads. An antibody test can also tell researchers when the virus has caused a fetus to be malformed, says Beer. Right now, that is not clear, because the virus itself has cleared by the time the animal is delivered. The tests will also prove which animals are safe for export.
[Byline: Debora MacKenzie]
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Communicated by:
ProMED-mail <promed@promedmail.org>
[SBV data as of 1 Mar 2012, including detailed country-maps, are available from the official web-sites of Belgium, Germany and Netherlands, as follows:
Country/last update/cattle/sheep/goats/total/map at
- Belgium/1 Mar 2012/37/138/1/176/http://www.afsca.be/_pictures/users/schmallenberg_20120229.jpg
- Germany/1 Mar 2012/58/701/38/797/http://www.fli.bund.de/fileadmin/dam_uploads/tierseuchen/Schmallenberg_Virus/Karten/Map_Schmallenberg_20120301.jpg
- Netherlands/1 Mar 2012/31/99/5/135/http://www.vwa.nl/txmpub/files/?p_file_id=2201854
UK's data, as of 27 Feb 2012, are the following (the BBC map is derived from the flutrackers web-site):
- UK/27 Feb 2012/5/78/0/83/
http://www.flutrackers.com/forum/showpost.php?p=444250&postcount=100.
According to France's most recent (weekly) update, as of 23 Feb 2012, the total number of SBV-confirmed cases in France was 277; for details, see
http://agriculture.gouv.fr/maladies-animales,11003. A map is available at
http://www.flutrackers.com/forum/showpost.php?p=443608&postcount=93
A single case each has been reported from Italy and Luxembourg.
Antibody determination by a validated, reliable technique is essential for prospective determination of SBV incidence (expected number of malformed newborns within the domestic ruminants population in the affected region) and retrospective study of the virus circulation. A sero-survey covering representative numbers of animals of all age groups will help to determine how long the virus has been circulating in the region, the actual population susceptibility, and the true need of vaccine. - Mod.AS
A HealthMap/ProMED-mail map can be accessed at:
http://healthmap.org/r/1wZE.]
See Also
Schmallenberg virus - Europe (21): Update 20120225.0455
Schmallenberg virus - Europe (20): Italy, Luxembourg, OIE 20120220.0418
Schmallenberg virus - Europe (19): update, RFI 20120218.0406
Schmallenberg virus - Europe (18): OIE, guidelines, int'l trade 20120217.0400]
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