Cattle farming, farmer with syringe, Bovilis BTV8 vaccine, vaccination for bluetongue viral disease© John Eveson/FLPA / imageBROKER/REX Shutterstock

A rapidly spreading strain of bluetongue virus has crossed the Austrian border, taking the number of bluetongue serotype four (BTV 4)-positive countries within Europe to three.

The outbreak, limited to three farms, has consisted of four cases so far in the eastern region of Burgenland. This has left a thousand cattle susceptible since laboratory reports confirmed the disease last Friday (13 November).

See also: Map of bluetongue outbreaks in France

The infected farms currently comprise a 126-animal unit in Neusiedl, a 69-cow herd in Hartberg-Fürstenfeld and a 10-cow herd in Jennersdorf.

Elsewhere, the same serotype has been reported by several countries to the east of Austria, while France continues to report cases of serotype one in central regions.

Serotype 4 is also known to be affecting livestock in Romania, Bosnia and Herzegovina and Croatia, which also reported an outbreak of serotype 1 in the summer. Serotyping is still “pending” on cases in Hungary.

Romania has reported six cases in cattle in the past month, with a large goat herd labelled “susceptible” and farms across the country being affected.

Austrian authorities have applied a raft of control measure, including screening, zoning and movement controls. No affected livestock have been treated or vaccinated.