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Published Date: 2013-02-09 18:12:31
Subject: PRO/AH> Schmallenberg virus - Europe (14): update
Archive Number: 20130209.1536928

SCHMALLENBERG VIRUS - EUROPE (14): UPDATE
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In this posting:
[1] Clinical cases, Swedish calves
[2] SBV in Welsh lambs
[3] SBV engineered SBV genome

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[1] Clinical cases, Swedish calves
Date: Fri 8 Feb 2013
Source: UNT.SE, Sweden [mach. transl., edited]
http://www.unt.se/sverige/schmallenberg-hos-svenska-kalvar-2265275.aspx

Schmallenberg in Swedish calves
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For the 1st time, Schmallenberg virus [SBV] has been detected in Swedish calves, one in Skane and one in Uppland, reports the agricultural magazine ATL online. The virus has spread rapidly during last year across the country.

SBV is spread by midges and has for the past year been widely distributed across the country. It infects cloven-hoofed animals, including sheep and goats, and can induce females to abort their fetuses or cause birth defects in their offspring.

The virus was 1st detected in Schmallenberg in Germany in autumn 2011.

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[2] SBV in Welsh lambs
Date: Fri 8 Feb 2013
Source: BBC News Wales [summarised, edited]
http://www.bbc.co.uk/news/uk-wales-21377317

Schmallenberg virus cases increase in Welsh lambs
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A virus that leads to birth defects in lambs is being increasingly detected in Wales, say farmers and vets. The Schmallenberg virus [SBV] is carried by insects and was 1st detected in Germany 18 months ago. But some farmers in lowland areas of south Wales say it is now clear the disease has reached Wales.

UK government officials believe there are now more than 1200 cases of the infection in Wales and England, but they say it poses no human threat. However, it is a growing concern for Welsh sheep farmers who are becoming increasingly worried about the disease's impact on flocks.

Colin Evans, who farms at Pant y Goitre farm in the Usk Valley in Monmouthshire, said between 20 and 25 lambs born to his 800 ewes appeared to have been affected by SBV -- up to 5 per cent of the flock.

"There are very few [farmers] that I speak to who haven't had a case, so we understand it now and are quite concerned by it because unless we find a control for this through a vaccine, we are concerned that our 3 to 5 per cent loss might become 20 per cent by next year," Mr Evans said.

Dylan Morgan, deputy director of the National Farmers' Union (NFU) Cymru, said more and more sheep farmers were likely to be affected, and there were concerns for cattle farmers too. "I think cattle is more of a worry than sheep," he said.

The disease has reached as far west as Swansea and Gower, where vet Ifan Lloyd said there had been lamb losses. But because there is no legal requirement to notify authorities about the virus, he said it is difficult to get a clear idea about how many cases are being death with in Wales.

"We saw the 1st case, the 1st confirmed case, back at the end of the summer and we've certainly seen more cases in late autumn, mid-winter particularly back in December in ewes that were lambing," said Mr Lloyd.

Scientists and vets fear that many farmers prefer to either keep quiet in case it harms the industry -- or are simply guessing they've had SBV, with an unusually high number of lambs being born with abnormalities.

A potential vaccine for the disease is currently being tested by the Veterinary Medicines Directorate but, as yet, there is no timescale for when it could be approved or introduced.

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[3] SBV engineered SBV genome
Date: 5 Feb 2013
Source: Vetscite.org [edited]
http://www.vetscite.org/publish/items/007776/index.html

Schmallenberg virus genome engineered to understand how to reduce disease caused by the virus
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"Scientists engineer the Schmallenberg virus genome to understand how to reduce disease caused by the virus. Researchers from the MRC Centre for Virus Research at the University of Glasgow in Scotland have developed methods to synthesize and change the genome of Schmallenberg virus (SBV). SBV is a recently discovered pathogen of livestock such as cattle, sheep and goats. The researchers have laid bare important ways by which this virus causes disease. The full report about the study published on 10 Jan 2013 in the Open Access journal, PLOS Pathogens. SBV is of great concern because it causes stillbirths, abortions and fetal defects in pregnant cows and ewes. It has spread rapidly throughout Europe since its discovery in Germany less than 18 months ago (in October 2011).

"The new study describes researchers' use of molecular biological methods to design and assemble the viral "genome" completely in a test tube in a form that can be easily introduced and replicated in cultured cells. From these cells the researchers recovered virus with identical infection properties to the 'natural' SBV. This approach, known as "reverse genetics", allowed them to control the viral genome and identify a gene (called NSs) involved in protecting the virus against the immune response of infected animals.

"The researchers made viruses missing the NSs gene and found they made mice in the laboratory less sick than viruses containing the NSs gene. The researchers also discovered that SBV rapidly grows in the brain and spinal cord of aborted lambs and calves. The virus prefers to infect cells called neurons, which explains why it infects and damages the brain. This also results in muscular defects such as abnormally flexed legs often seen in stillborn animals when virus is transmitted from an SBV infected mother to the calves or lambs in the uterus during pregnancy. Scottish researchers, led by Massimo Palmarini and Alain Kohl, suggest that the ability to engineer and control the SBV genome will allow the future development of new vaccines for this virus that is of great concern to European farmers."

[byline: Science Daily]

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[The citation for the paper, referred to in item 3 above, is:
Varela M, Schnettler E, Caporale M, Murgia C, Barry G, et al. Schmallenberg Virus Pathogenesis, Tropism and Interaction with the Innate Immune System of the Host. PLoS Pathog 2013; 9(1): e1003133. doi:10.1371/journal.ppat.1003133. The paper is available online at http://www.plospathogens.org/article/info%3Adoi%2F10.1371%2Fjournal.ppat.1003133. - Mod.AS

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