France has reported a single case of BTV-4, a different strain of bluetongue to the more common BTV-8, in a bovine in Haute Savoie region of the country.

The animal in question tested positive for virus under the framework of pre-movement testing and has been humanely destroyed.

French authorities has put disease control measures are in place around the farm of origin, including surveillance and mandatory vaccination in the surrounding 20km control and 100km prevention zones and surveillance in the additional 50km surveillance zone.

The location of the holding of origin is close to the Italian and Swiss borders, and the respective authorities in each country have been notified as the zones also cover part of their territory.

The Department for Environment, Food and Rural Affairs (DEFRA) reports that the French Authorities have said the animal in question was a 15-day old veal calf which had been born in the Haute Savoie and then moved to a fattening farm in Allier region, where testing was carried out, prior to being moved to Spain. The animals at the fattening farm are also being tested.

Disease origin

Meanwhile, the origin of disease is not known. DEFRA reports that BTV-4 has been circulating at high levels on the islands of Corsica and Sardinia this year and was present earlier in the year in northeast Italy. Vaccination is mandatory on Corsica and particularly for any animals which leave the restriction zone.

The cases in northeast Italy were likely a result of spread from the neighbouring countries in the Balkans and southeast region of Europe, where disease was circulating widely in previous years.

Surveillance around the infected calf’s place of origin is being carried out and DEFRA said it will be interesting to understand the origin and infection status of the dam.

BTV-4 is not known to be transplacentally transmitted, unlike BTV-8 (Darpel et al., 2009), but without understanding the full viral characteristics it is too early to speculate, according to DEFRA.

Risk level

This new outbreak in France has no impact on the current risk level for the UK, DEFRA stated.

Although inactivated BTV-4 vaccine is authorised for use in the EU, it is not currently available for distribution in the UK, except under a special import certificate, but if the risk increases, the UK Veterinary Medicines Directorate are able to grant a marketing authorisation should the need arise.

DEFRA will continue to monitor the current situation in France and disseminate any further updates from the French Authorities, particularly with regards to the most recent cases and the BTV-4 situation.

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