sexta-feira, 24 de fevereiro de 2012

Schmallenberg Spreads Relentlessly Across Europe

EU - Over the last few months Schmallenberg has spread to seven EU countries, affecting more than 1000 animals. This week Italy and Luxembourg report their first cases. Charlotte Johnston, TheCattleSite editor gives an overview of the virus to date, but keep in mind more and more cases are being reported every day so the number of animals affected will change.

The virus was first detected in Germany by the Friedrich-Loeffler-Institute, in November 2011.

The virus is not contagious from one animal to another, but is transmitted by insects, most likely midges, and presents no harm to human health.

There are no on-farm tests or vaccines available to protect livestock. Farmers are being urged to continue to check their animals and report any suspicious symptoms to their vet, the more information available the quicker a solution can be found.

In sheep the virus is mainly identified through malformed lambs with brain dysfunctions. The abnormalities are a consequence of infection at an earlier stage in the pregnancy.

Few cases have been found in cattle yet, but the main calving season for Europe is around March/ April and it is suspected that more cases will crop up.

Gwyn Jones, vice chairman of the Copa Animal Health and Welfare Group which represents all EU farming unions, said collaborative action would be essential to stamp out the disease.

Schmallenberg Cases in EU

Cattle Sheep Goats Total
Germany 25 577 27 629
France 3 164 0 167
UK 4 48 0 52
Belgium 10 116 1 127
Netherlands 4 94 4 102
Luxembourg 0 1 0 1
Italy 0 0 1 1
Total 46 1000 33 1079

In Germany the virus has been detected on 629 farms. Of the affected are 25 cattle, 577 sheep and 27 goats.

The OIE has reported this week that the Schmallenberg virus has been identified in Italy, in Vento, which is near the Austrian/ Slovenian border.

Only one breeding goat has tested positive with the virus, and that goat was born on the farm in Italy last February. A pregnant goat delivered one healthy small sized kid and due to some complications died the day after. At necropsy a dystocic malformed foetus was found, which resulted positive. It was not possible to perform diagnostic examinations on the dead goat.

To date there have been 52 cases of Schmallenberg in the UK, all in the South of the country. Farms in the South West and South East are likely to be at a higher risk of contracting the virus. Of the total cases in the UK, only four cattle have been identified with the virus.

This week, Luxembourg has announced that a sheep in Clervaux has tested positive for the virus.

It appears that much of France was infected with the virus last year, although it went relatively unnoticed. Earlier in February, France reported 164 sheep have been affected by the virus in over 25 states.

102 farms in the Netherlands have been affected.

Belgium has seen the second highest amount of cattle affected, with 10 positive cases.

Schmallenberg Virus
Schmallenberg virus gets its name from the German, Winterberg, where the virus was first identified in cattle in November 2011. After testing ruled out various other illness's, the orthobunyavirus (Schmallenberg virus) was identified by metagenomic analysis and virus isolation of infected cattle in Germany.

The Schmallenberg virus is related to the Simbu serogroup viruses, in particular Shamonda, Akabane, and Aino virus.

So far, research confirms that the virus is vector-borne, spread by insects, mainly flies/ midges.

The virus affects cattle, bison, sheep and goats. To date (February 2011) the disease has mostly been recognised in small ruminants around the time of partuition, with offspring showing signs of brain damage or malformations.

There is no risk to human health, says the OIE.

Clinical symptoms

Manifestation of clinical signs varies by species: bovine adults have shown a mild form of acute disease during the vector season, congenital malformations have affected more species of ruminants (to date: cattle, sheep, goat and bison). Some dairy sheep farms have also reported diarrhoea.

Adults (cattle)
-Probably often inapparent, but some acute disease during the vector-active season
-Impaired general condition
-Reduced milk yield (by up to 50%)
-Recovery within a few days for the individuals, 2-3 weeks at the herd scale

Malformed animals and stillbirths (calves, lambs, kids)
-Arthrogryposis (abnormal joints)
-Hydrocephaly (build up of fluid in skull)
-Brachygnathia inferior (overshot jaw)
-Ankylosis (stiff joints)
-Torticollis (twisted neck)
-Scoliosis (deformed spine)

As of yet there is no vaccine for the virus, which will take some times, perhaps up to two years, to develop. Farmers are urged to stay vigilant and report any suspected cases.

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